Port cranes: a big story about powerful technology. Gantry Crane Gantry Jib Crane

Port portal cranes

Port portal cranes usually have a lifting capacity of 3 to 15 tf with a total dead weight of 60 to 200 tf and the weight of the heaviest mounting element from 6 to 30 tf. The lifting capacity of shipbuilding portal cranes ranges from 30 to 75 tf and higher with a total crane weight of 300-700 tf.

Gantry cranes are mounted using mounting booms, portals or portal cranes existing in the port, as well as large floating cranes. Mounting booms and portals are mainly used in cases where there are no portal or floating cranes of the required lifting capacity in the port, and the booms are used for mounting single cranes, and the portals are mainly used for serial installation. The mounting boom is used in an inclined version, and the crane portal moves along the tracks during the assembly process. The carrying capacity of the mounting boom usually does not exceed 20, less often 30 tf, and therefore it does not allow significant enlargement of the blocks.

Rice. 1. Scheme of sequential operations of mounting a portal crane on a turntable by the superstructure method

On fig. 1 shows a typical sequence (positions 1-12) of mounting a gantry crane with a slewing ring by the superstructure method, carried out using mounting means of limited capacity. As can be seen from the figure, here the portal is assembled from two pre-enlarged facade frames (position 2) with the subsequent installation of gratings (position 3), the upper platform of the portal (position 4) and a rotary frame (position 5). The assembly of mechanisms and frame (position 6-5) on the swing frame is carried out at the design level, the boom (position 8-11) is installed in the assembly with the trunk, but without the truss. By the time the boom is attached to the counterweight levers, the ballast of the latter

in the amount of at least 50% has already been put in place. The question of the moment of installation of fixed counterweights of the rotary part (before or after the installation of the boom) is usually decided according to the instructions of the manufacturer, based on the condition of ensuring the stability of the crane during installation. Here, the largest lifting height is determined by the installation condition of the truss (position 12), and the largest weight is determined by the weight of the crane turntable.

On fig. 2 shows the installation sequence of a 5-ton slewing-string crane with flanged field joints.

Rice. 158, but reflects the assembly of one of the legs of the portal with a cross beam; rice. 2, b - installation of a leg with a cross beam on the undercarriage, their temporary reinforcement with a spacer and the attachment of the remaining three legs to the cross beam; rice. 2, c - installation of the annular head of the portal; rice. 2, d, installation of the lower part of the rotary column, assembled into an enlarged block by the elements of the machine platform; rice. 2.5 - installation of the upper part of the column with a drive mechanism for changing the departure; rice. 2, e - installation of the mechanisms of the rotary part, the crane operator's cabin and the machine cabin; rice. 2, g - installation of counterweight levers, installation of the counterweight and lifting of the boom using a mounting chain hoist driven by a crane winch.

Rice. Fig. 2. Scheme of sequential operations for mounting a portal crane on a swivel column by the superstructure method

Mounting portals with a lifting capacity of up to 150 tf at a height of 30-40 m allow the installation of portal cranes of all sizes in large units. In these cases (Fig. 159), both assembly and installation work are carried out under the mounting portal, in connection with which the crane portal, after its assembly, is removed from under the mounting portal and inserted under it after lifting the rotary part to install the latter.

If large floating cranes (with a lifting capacity of 100-200 tf) are available, gantry cranes are assembled at zero using caterpillar tracks in two or three enlarged blocks, which are then installed by a floating crane. Due to the high rents of heavy-duty floating cranes, they are brought to the site only for the final lifts.

Rice. 3. Scheme of installation of a portal crane with pre-aggregated blocks

In the case of using portal cranes existing in the port for installation, they tend to work with twin cranes, which makes it possible to enlarge the units up to a weight of 20-30 g (with 10-15-ton cranes).

Assembly work on the portal and the turning part can be carried out relatively independently.

The assembly of the portal is usually carried out directly on the working path or on a section of the assembly path. In both cases, the track on which the portal is assembled must meet the crane runway tolerance standards, and first of all, in terms of gauge accuracy and equal height of the rail heads under the portal bogies. Since the path may sag during the installation process, its marks are periodically checked by leveling.

The portal is assembled directly on its undercarriages, which are pre-arranged on the crane runway so that all right or all left flanges of the wheels of all bogies are pressed against the rail. This position is controlled throughout the assembly of the portal in order to maintain the correct gauge of the bogies.

Before the final connection of the mounting joints of the portal, the following are checked: the dimensions of the track along the front and rear bogies, the equality of the diagonals of the portal at the level of the bogies and the equality of the diagonals along its faces. In addition, the upper face of the portal (if it is assembled from several elements) is checked for flatness in the area where the turntable rests on it.

The assembly of the portal for cranes with a slewing circle ends with the installation of the slewing drum (if it is made as a separate mounting element). When installing the drum, turntable with the help of a thickness gauge placed on the central pin, the following tolerances are checked: concentricity of the pin to the lantern ring, fluctuations in the height of the lantern flanges; the correctness of the circumference of a circular rail - only for a conical rail; rail flatness. In addition, the pitch of the pins at the joints of the drum is checked using a caliper.

Rice. 4. To check the assembly of the crane turntable drum

For cranes on a slewing ring, after the swivel assembly or slewing platform is installed on the portal, the slewing ring and the engagement of the crown with the sprocket are checked. To do this, the platform is slowly rotated, observing the resistance to rotation, the conditions of engagement (side clearance) of the sprocket and the lantern ring, as well as the conditions of contact between the support wheels with the rail or the rollers with the top tires.

At the end of the assembly, the lower part of the column is inserted into the crane portal on the slewing column and the following adjustments of the slewing device are made. First, the position of the horizontal support wheels relative to the annular rail is adjusted in order to obtain the smallest clearance between them and the rail. At the same time, if possible, the operation of the engagement of the crown pair is also checked, since the lateral clearance in the engagement is associated with the installation of the wheels.

Rice. 5. Schemes of checks of the assembly of support bases (on the portal) of the crane slewing column

When assembling the frames of the rotary part of cranes with articulated booms, the actual positions and relative distortions of the holes for the hinges of the jib kinematic system are controlled.

A special place in the installation of portal cranes is occupied by the installation of jibs, and first of all, jibs of an articulated type. The main scheme for installing such jibs is the scheme shown in fig. 6, a. Here, the jib assembly with spacers between its links is installed on the crane in the position of the smallest overhang, which allows you to keep the counterweight of the boom also in the position of the smallest overhang. In this case, a significant lifting height of the mounting means is required, which ensures the suspension of the jib above its center of gravity.

Rice. 6. Schemes for installing articulated jibs

With a limited lifting height of the mounting means, the boom can be installed in the position of the longest reach (Fig. 6, b), but then the counterweight lever must also be preliminarily raised to the position of the longest reach, which often presents known difficulties. The boom can also be mounted on a crane with an outreach exceeding the maximum working one (Fig. 6, c), which requires an even lower lifting height and allows you to keep the counterweight in the position of the smallest outreach, but necessitates the use of a special chain hoist P to bring the boom to the position of the smallest outreach .

In cases where the lifting capacity of the mounting devices is insufficient to lift the jib in its entirety, the truss can be lifted separately, and sometimes (especially heavy jibs) the boom is raised in three steps (the root part, the top with the trunk and the truss). Installing the trunk on the boom at the design level, due to the difficulty of this operation, is avoided.

Lifting the boom by the end of the trunk, which is used when the lifting height of the mounting means is insufficient, is not recommended, as this often leads to accidents caused by the twisting of the booms.

Mounting movements of portal cranes between parallel tracks are usually carried out along a temporary perpendicular path, for which the portal carts are turned 90 °.

Movements between non-parallel paths, as well as rotations of the portal relative to the vertical axis, are carried out due to the movement of the crane along curves.

Rice. 7. Scheme of inscribing a four-wheeled crane trolley into a curved rail of the mounting track

Rice. 8. Scheme of inscribing the crane portal on the transition section of the curvilinear mounting path

Rice. 9. Portal crane: 1 - legs, 2 - undercarriages, 3 - swivel frame, 4 - upper portal assembly, 5 - boom, 6 - cab, 7 - brace, 8 - frame, 9 - counterweight, 10 - stationary counterweight, 11 - control post (cabin)

A gantry crane is a universal intermittent handling machine, usually with an electric drive powered by the shore electrical network. The portal crane got its name because its base is made in the form of a letter. The main elements of the portal are legs resting on undercarriages connected in the upper part by a span structure. The wheels of the trolleys rest on the crane runways along which the crane moves. The dimensions of the portal are selected in such a way that trains can pass between its legs. Depending on the number of railway tracks laid under the portal, single-track, double-track and three-track portals are distinguished.

Sometimes the portal is replaced by a semi-portal, which has only two legs. The superstructure through a pair of running carts rests on a rail laid on the wall of the warehouse. The rollers or rollers of the swivel frame with the frame fixed on it rotate around the vertical axis (baller) installed on the portal. This axis prevents the possibility of radial shift of the rotary part of the crane. The control station is located on the side of the boom; on the opposite side, a fixed counterweight is attached to the frame.

The portal crane has the following movements: lifting (lowering) the load, changing the outreach of the boom, turning around the stock, moving the portal along the crane tracks.

Accordingly, the gantry crane has a lifting mechanism, a luffing mechanism, a slewing mechanism, and a traveling mechanism. The lifting mechanism (the main mechanism of the crane) is also called a lifting winch and consists of an electric motor, a gearbox, a cargo drum on which the cargo rope is wound, and a braking device. If there is only one drum, the winch is called single-drum. Two-drum winches are widely used, which can rotate simultaneously or separately, which allows the crane operator to control the grab or other attachment to grab the load.

The rotary mechanism and the mechanism for changing the reach of the boom are also located on the rotary part of the crane. Movement mechanisms are usually installed in undercarriages.

When changing the reach, the boom moves along a certain radius, while the load moves only horizontally. This is achieved by using various special devices. On the crane shown in Fig. 9, such a device is a jib hinged at the end of the boom and a flexible brace.

The main parameters of cranes are carrying capacity, the magnitude of the maximum reach of the boom, operating speeds.

The lifting capacity of cranes is standardized. In mass transshipment operations, there are portal cranes with a lifting capacity of 5, 10, 15 tons. Cranes with a lifting capacity of 5 tons are used mainly for reloading basic cargo. For reloading heavyweights, equipment, bulk bulk cargo, cranes with a lifting capacity of 10 and 15 tons are used.

The boom outreach is measured from the axis of rotation of the crane, usually its maximum value is 25-30 m.

Its performance depends on the operating speeds of the crane, however, design considerations force them to be limited to the following limits: load lifting speed 45-80 m / min, turning speed 1.5-2 rpm, boom change speed 50-60 m / min, portal movement speed 20-30 m/min.

Cranes with lower lifting capacity have higher speeds.

TO category: - Port handling vehicles

The park of portal cranes of the USSR since the post-war period has been replenished in two ways: manufacturing at its own factories and obtaining cranes from imports. As sad as it is to admit, there were more gantry cranes imported into the USSR than our own production. Not many times, but more. The main suppliers were the factories of the GDR and Hungary. During the war, cranes made in the USA appeared. In the 1950s, cranes came from Italy and France; from the 60s, cranes from Finland began to appear. But cranes from these countries came in small quantities, not comparable with Hungarian and German ones. The supply of imported cranes to Russia and the states of the former USSR has practically ceased since the beginning of the 90s. In this article, imported cranes will not be considered.

In the USSR, there was a parent enterprise for the production of gantry cranes - the S.M. Kirov Lifting and Transport Equipment Plant, leading its history from the mechanical workshops of St. Petersburg - the Warsaw Railway (the third largest in Russia). The plant was located on the Obvodny Canal in Leningrad, and when creating associations in the early 70s of the twentieth century, it became part of the Podyemtransmash association. From the beginning of the 90s, production fell sharply, and by the beginning of the 2000s, only a few portals were being assembled per year using parts from old stocks. The last known gantry was shipped from the factory in 2001. Further, the fate of the plant is quite typical - the formation of several small firms on its basis, the sale of the territory, a business center was organized in one building, the rest were demolished with the construction of a hypermarket and a parking lot in their place.

If ZPTO named after Kirov in the period 1948-2001 produced portal cranes constantly, then there were a number of enterprises that produced portal cranes for a certain period of time. Unfortunately, the history of the production of portal cranes on them now has more mysteries than answers, so we cannot describe them in detail. So far, the following enterprises are known: "Zhdanovmash", Zhdanov (now - Mariupol, the enterprise - "Azovmash"); "Sibtyazhmash", Novosibirsk; "Kommunar" and Plant of mining equipment, Perm; Bureysky mechanical (crane) plant. It is possible that there were a number of other enterprises that produced portal cranes until the 1990-2000s, but there is no information on them and it is unlikely that the number of cranes produced by them was more than a few. In the 2000s, half a dozen enterprises in Russia and Ukraine began to manufacture portal cranes, but they were far from even together in Soviet times to the volume of production of ZPTO named after Kirov in Soviet times.

The current marking of portal cranes consists of 3 letters and numbers (according to the old system 4 letters):
TO- Tap;
P- portal;
P / M / D- reloading / assembly / docking;
G / TO- clamshell / hook (old designation system).
Numerical indexes usually indicate: 1 - maximum load capacity of the main hook / at maximum outreach; 2 - maximum departure; 3 - portal track. With variable values ​​​​of carrying capacity at different departures, the carrying capacity and departure can be indicated by two digits through a fraction - at the maximum reach and at the departure of the maximum carrying capacity.

Now let's take a closer look at the classification of portal cranes by purpose:
1) Transfer crane (the most massive type of crane). Load capacity varies between 5 - 30 tons for different models. It can be equipped with a bulk grab, a magnetic washer for scrap metal, or a hook suspension for piece cargo. Grab cranes usually have two identical winches for grapple operation. When operating such cranes with a hook, only one winch is used.

2) Mounting crane. Widely used in ports, shipyards, shipyards. It is structurally identical to the transfer crane and is distinguished by the presence of a jib on the trunk and low speeds of the hook. The winch is either one or two different - for the main and auxiliary lifts. G / p in the range of 12.5 - 160 tons for various models.

3) A slipway crane. This type is one of the smallest. At its core, this is an assembly crane and is used exclusively in shipbuilding enterprises. Designed for mounting the ship's hull. Design features are a very high portal and a trolley current lead. A feature of the mode of operation, it should be noted quite often the retention of loads close to the maximum, on weight for a long time (usually, the installation of a section of the vessel takes several days). It has a large carrying capacity and low landing speeds. Usually the capacity is in the range of 30 - 160 tons.

4) Dock portal crane. Due to the specifics of the work performed, it has a relatively small carrying capacity. The design features are: a narrow portal (since the width of the dock tower is limited), the presence, in addition to anti-theft grips, also rollover protection. It has limitations on the ability to work in waves.

So, we figured out the purpose and the correct name, now you can get acquainted in more detail with the main structural elements of the type of cranes in question.
Portal. The main purpose is to reduce the weight of the counterweights (and, accordingly, the weight of the crane itself) by increasing the area, projecting onto which the center of mass does not cause the crane to tip over. The second purpose is to pass between the legs of road or rail transport, travel over mechanisms or structures. It should be noted that not all portal cranes allow (not necessary) the passage of vehicles, and passage over mechanisms and structures is extremely rare, since it is impossible at the working site and is allowed only when moving from the working site to the repair one. The portal consists of legs and a head. The legs can be placed symmetrically, but usually the portal is not a square in plan, but is elongated along one coordinate. The most common cranes with a symmetrical portal are "Kirovtsy" (cranes ZPTO named after S.M. Kirov) with a passage distance of 10.5 m (two railway tracks). Usually, ties, ladders and other equipment are located between the legs located along the rail.

Leg- the element of the portal (usually 4, but in older designs there are portals with 3 legs) at the bottom ends with one or more carts. Carts are motor or idle. There is no engine on the idle bogie. Typically, a gantry crane has four travel motors, i.e. one for each leg. In this case, the leg ends with a trolley with two wheels, one of which is powered by an engine. There are cranes with only two legs motorized, but these are very light cranes and this option is very rare.
There are also portal cranes with 8 or 16 (very rare) movement engines. These are heavy cranes, they have up to 4 (four) trolleys per leg, and sometimes the inner extreme trolleys of adjacent legs have an additional connection in the form of a balancer. Combinations of motor and idle carts on one leg in this case may be the most bizarre.
End carts must necessarily end with buffers. Anti-theft grips are required on trolleys, their minimum number is one per leg, and more if the mass of the crane is such that one on the leg may not be enough to hold the mass of the crane at the calculated wind load. On dock gantry cranes, in addition to anti-theft grips, roll restraint devices are provided, which are also usually mounted on a trolley. The inside of the leg is usually used for cable management. Ladders for the driver inside the legs are not placed, only outside.

portal head- the top of the "stool". It serves to connect the legs, the main purpose is to receive loads from the rotary part on the support bearing. In the head there is electrical equipment that ensures the movement of the crane. It happens in different forms. For example, on the old "Kirovtsy" it had a square shape in plan, on the later ones it was round.

Travel distance it is standardly considered in railway tracks - 1, 2 or 3. Most common on 2 tracks (10.5 meters). Portal cranes that do not work with vehicles inside the gantry may have a different width. Thus, building portal cranes usually have a reduced passage width.

current lead there are two performances. The most common is the cable drum and flexible cable, which is wound or unwound as the crane travels. The cable drum is usually located on one of the legs, or together with anti-theft grips on the crossbar connecting the two legs. Requires minimal capital costs, reliable. It is mainly used in ports. A rather rare option is a trolley current lead, which is a long room below the level of the tracks, in which trolleys are stretched, and the crane has a special rod with current collectors. It is used in shipyards, where there is a risk of damage to the flexible cable, and the possibility of crossing the tracks by transport is necessary at any place.

Upper swivel structure consists of a rotary part connected with the portal by means of turntables of various designs, an arrow and a counterweight.

Slewing device for domestic cranes manufactured by ZPTO named after Kirov, the roller swivel device on the slewing ring was most widely used. With this design, the turntable rests on rollers that are in contact with two horizontal rails placed on the portal and on the turntable.
A good example of a slewing device on a column is the KPPG-5 crane. This design consists of two nodes: upper and lower. The upper node is a system of horizontal rollers (depending on the loads - single or double on the balancer) mounted on the column and transferring the load to the portal in any direction of the vertical moment M. The lower node perceives vertical pressure from the weight of the rotary part with the load and horizontal from the moment M.

Boom devices in gantry cranes, the change in reach is a working, not an installation movement, i.e. performed with a load at high speeds of its horizontal movement. The working nature of the change in departure determines the two most important requirements for boom devices:
1) The boom device must be fully balanced relative to the swing axis of the boom, which is achieved with the help of movable counterweights;
2) When changing the departure, the cargo must move along a trajectory that differs little from the horizontal.

The main types of arrows are:
- straight booms, both with devices that allow the load to move horizontally, and without them. An example of a dock crane and a KPPG-5 crane
- Articulated booms with a jib cable guy, used in the period 1930-1990s.
Articulated booms with a rigid jib brace have the advantage of being partially unloaded from torsion during transverse swinging of the load.

Departure change mechanisms - there are:
- Rod type (the most common), they can be used with gear racks or screw rods;
- Hydraulic;
- Polyspast, where the departure change occurs by tightening the movable and fixed clips;
- Sector, used in the early designs of cranes, where the counterweight was at the lower end of the boom;
- Crank, provide reciprocating motion of the boom.

This is a lifting equipment with a rotating part installed on a mobile metal structure, running on rails and capable of passing railway cars and other vehicles under it. Gantry cranes are widely used in the construction of power buildings, locks, dams, hydroelectric power stations and other important facilities. They are actively used in ship docks and cordon warehouses, when working with bulk, responsible piece, bulk cargo.

Portal crane device

In general, it consists of the following mechanisms:

Leg - an element with a trolley at the bottom (idle or motorized), providing movement along the crane track. The number of legs varies depending on the model and can be either 3 or 4 (classic version), or 8 or even 16. All trolleys are equipped with an anti-theft grip, each has an individual drive (if they are motorized), and the extreme ones are necessarily buffered .

Head - a platform for connecting legs, square or round. In addition to the final formation of the portal, with a passage of 10.5 m (standard for 2 tracks) or some other, it is also a connection point for electrical equipment - all bogie drives. Plus, the head is also a supporting element that receives loads from the rotary device.

Current lead - a cable, flexible or on a drum, which is attached to one of the legs or to the connecting crossbar, and is wound / unwound when the crane moves. Also, current can be supplied using a trolley, but this is a rather costly option, which is used only when it is impractical to lay a cable on a work site due to the high probability of its breakage or damage.

Rotary device - a column or a circle on the rollers in contact with the head. Supports and centers the drive that ensures the rotation of the gantry crane. Transfers loads and vertical pressure to the head.

Boom device - with a gripping mechanism that performs the operations of vertical and horizontal (if the reach can be changed) movement of goods. It is equipped with a system of movable counterweights, thanks to which, during operation, balance is achieved with respect to the swing axis.

Classification of portal cranes

By appointment distinguish:

According to the type (scheme) of the arrow, there are:

• straight lines - the departure remains unchanged;
• articulated - with a flexible or rigid guy, a straight or profiled trunk, leveling blocks or tackles - all this is aimed at changing the departure;

According to the design of the portal, cranes are classified into:

• lattice - each leg is a separate structure;
• frame - the legs are connected in pairs and thus attached to the crossbar through the head;
• frame-tower - similar to the previous ones, but only reach the head;
• frame-diagonal - each leg is pivotally attached to the crossbar.

According to the number of supports (legs) there are:

• three-
• four-
• multi-support.

According to the number of connection of legs with the upper crossbar, portal cranes:

• two-
• four-
• multi-rack.

In this case, the nature of the connection of the legs with the upper crossbar can be:

• rigid - the legs do not move;
• hinged - the supports can change their position (after the head).

According to the undercarriage, portal cranes are:

• on rails - they move exclusively along the laid path;
• pneumatic-wheeled - more mobile, even their turns on the spot are possible.

3.1 Portal cranes.

A gantry crane is a complex hoisting and transport machine, the design complexity of which is determined by the complexity of technological operations and increased requirements for the accuracy of execution and operation of the crane.

Figure 3.1 - Portal crane. General form.
1-way trolley;

4-fixed counterweight;

5-cabin control;

6-cabin for mechanisms;

7-mechanism for changing departure;

8-movable counterweight;

10-hard guy;

12-shift working equipment;

3.2 Classification of portal cranes according to their purpose

According to their functional purpose, portal cranes are divided into: reloading, assembly, construction, shipbuilding (Fig. 3.2)

Figure 3.2 - Block diagram of the classification of portal cranes
3.3 Portal cranes

Port cranes. The lifting capacity of cranes used in ports for loading bulk cargo ranges from 1.5 to 20 tons. With a carrying capacity of more than 3 tons, they are usually supplied with interchangeable equipment - grabs for handling bulk cargo and hooks for handling piece cargo. For cranes with a lifting capacity of up to 3 tons, inclusive, the use of grabs is very limited, they are mainly used to supply coastal and river ships with coal. Therefore, in order to simplify the lifting mechanism, such cranes are usually made only with hooks. For specialized sea berths with large amounts of bulk cargo, it is advisable to use grab cranes with a lifting capacity of up to 25 tons.

Port cranes usually have a constant lifting capacity on all outreaches. Depending on the width of cordon warehouses and serviced vessels, port cranes have a maximum reach of 15 to 40 m (and 30 m is usually 25). The minimum overhang is taken from design considerations. In order to serve the largest area from one crane installation, one should strive to have this overhang as short as possible. The gauge of the portal (the distance between the axes of the crane rails depends on the number of railway tracks blocked by the portal. Usually, the portals are made single-track, three-track, double-track and. In some cases, the portals are replaced by L-shaped semi-portals, in which the horizontal frame of the metal structure on one side rests directly on the undercarriages, rolling on crane rails laid on the supporting structures of cordon warehouses (Fig. 3.3) or on special flyovers.

Figure 3.3 - Semi-portal crane
at different levels (Fig. 3.4). This makes it possible to bring the axis of rotation of the crane closer to the ship being unloaded, without resorting to the construction of expensive massive embankment walls. With large fluctuations in the water level in the river during floods, the undercarriages running along the lower rail and part of the metal structure of the semi-portal often work under water.

The turning part of the crane on a single-track portal is installed in the middle of its span; on a double-track portal, it sometimes shifts to one of the crane rails, depending on the operating conditions of the crane. The rotary part of the crane on a three-way portal is sometimes movable, which increases the serviced area, but complicates the design of the crane.

Due to the high cost of the construction of crane runways and embankments, the pressure on the running wheels of cranes is usually limited to 20-30 tons. Depending on this pressure, the number of running wheels is determined.

Figure 3.4 - Portal crane on a semi-gantry of a special design
Possibilities of using gantry cranes for a wide range of operations:

▬ transshipment of piece cargo with the help of a cargo hook;

▬ work with heavy loads;

▬ bulk cargo handling with a grab;

▬ work with a magnet;

▬ handling of scrap metal using a rectangular grab;

▬ handling of containers using a spreader.

Cranes with a bunker (cranes of the "kangaroo" type) on the portal (Fig. 5) are used to unload bulk cargo from ships with a stable cargo flow.

Rotation is eliminated from the crane's duty cycle, thereby increasing productivity. The movement of the grab from the hold to the bunker and back is provided only by the mechanisms for lifting and changing the departure. From the grab

Figure 3.5 - Gantry cranes with a hopper (kangaroo type)
the cargo is poured into the bunker and delivered to the warehouse by conveyors, one or two of which are mounted on a crane. The dimensions of the bunker in plan, taking into account the rocking of the grab on the ropes, are significant. To reduce swinging, the length of the suspension should be as short as possible. When moving the crane along the vessel, the bunker should not protrude towards the shore rail beyond the size of the portal. In the crane of the plant PTO them. S. M. Kirov (Fig. 3.5, a) the bunker is made rotary. When unloading cargo from the ship, the hopper is installed horizontally, and when the crane moves along the pier - vertically; at the same time, the bunker does not touch the ship's superstructures. In the Kampnagel crane, for the same reasons, the bunker is made mobile (Fig. 5, b). This allows you to reduce the length of the movement of the grab and the weight of the boom system.

3.4 Assembly shipbuilding and ship repair cranes

Mounting cranes are designed for work with critical piece cargo. Shipbuilding and ship repair cranes are usually mounted on high portals to better serve ship erection and repair work. Gantry cranes installed on the embankments of shipyards for completion of ships afloat are called outfitting cranes. They are also used in the repair of ships at repair embankments and in dry docks.

Portal cranes used to assemble ship hulls on slipways are called slipway cranes (Fig. 3.6). The modern technology of building ships provides for the assembly of the ship's hull with large units, so the lifting capacity of slipway and outfitting cranes reaches 80 tons or more.

Figure 3.6 - Stave crane

The lifting height of the hook above the head of the crane rails of mounting cranes (Fig. 3.7) reaches 50 m. They are usually installed on special high portals (Fig. 3.7) and, starting with a lifting capacity of 20 tons or more, are equipped with two hooks - main and auxiliary.

Often erection cranes have a variable lifting capacity depending on the reach. The speeds of the working movements of such cranes, unlike reloading cranes, are assigned small.

For the convenience of installing the mounted equipment, the main lift mechanism, and sometimes other crane mechanisms, have an additional low (landing) speed. The maximum outreach of erection cranes sometimes reaches 35-40 m.

A special group is made up of dock cranes installed on the sides of floating docks (Fig. 3.8, 3.9 and 3.10), which serve to perform work inside the docks. They move along the dock wall along tracks with very little

Figure 3.7 - Mounting crane

Figure 3.8 - Dock crane with a lattice boom
gauge-3.0 to 4.5 m. In this regard, it is necessary to take special measures to ensure the stability of the cranes. The stability of the crane is provided by counterweights on the turning part and, if necessary, by pouring concrete into

Figure 3.9 - Dock crane with a box-type boom

Figure 3.10 - Application of dock cranes on floating docks (Riga shipyard)
portal supports. In addition to anti-theft grips, dock cranes are equipped with anti-tilt grips (toncer grips) that constantly cover the heads of crane rails and protect the crane from possible tipping during overloads and hold the crane when

side hurricane wind. Crane rails on the dock must be securely fastened to resist tearing forces. Sometimes the booms of dock cranes must be stowed in the stowed position for the duration of transportation on the high seas. Dock cranes are designed taking into account the roll and trim of the dock.

3.5 Construction portal cranes

Construction portal cranes are used for mechanization of construction works. The use of gantry cranes in construction due to their high cost is only advisable when reloading large quantities of materials, when the crane works for a long time in one place.

Figure 3.11 - Construction portal cranes on a concrete rack
At present, portal cranes are widely used in the construction of dams, locks and power buildings of large hydroelectric stations (Fig. 11) for laying concrete supplied in buckets along a concrete rack. The crane unloads the buckets, which are brought along the overpass under the crane portal, and delivers them to the blocks, where the buckets are emptied and loaded back onto vehicles. With the help of gantry cranes, formwork (in the form of panels), reinforcing trusses, slabs, shells, embedded parts of gates and turbines, etc. are installed and installed. At the end of construction, these cranes are used to mount the main equipment.

Construction portal cranes usually have a lifting capacity of 10-20 tons. Depending on the reach of the boom, it can be variable. The value of the maximum reach of these cranes depends on the width of the dams and reaches 50 m, the height of the hook above the head of the crane rails is 36 m. The depth of lowering the hook below the head of the crane rail depends on the height of the overpass and reaches 70 m or more.

To ensure high productivity at such high lifting heights, construction cranes have the same high lifting speeds as transfer cranes. However, the rate of turn and change

Figure 3.12 - Construction gantry crane with increased lifting capacity in the port of Baltimore, USA
departures for construction cranes are somewhat less than for reloading cranes, due to the need to reduce the swinging of the load, which usually hangs on long ropes. Construction cranes are made only with hook cranes. Their portals are of great height, since under them reinforcing trusses and pipeline shells to turbines can be transported along the overpass (Fig. 3.12).

When considering various types of portal cranes, it is most correct to distinguish them according to the kinematic schemes of the booms, which determine both the design of the crane as a whole and its performance.

Figure 3.13 - Simple lifting boom
A simple lifting boom is shown in (Fig. 3.13). Such an boom does not provide horizontal movement of the load when changing the reach.

The imbalance in the weight of the boom and lifting or lowering the load when changing the reach require very powerful mechanisms for changing the reach, so such booms are found only in older types of cranes. Cranes with simple booms have reduced productivity, since it takes a lot of time to set the load in the right position.

At present, fully or partially balanced booms are used for portal cranes, which ensure the movement of cargo along a trajectory that is close to horizontal. The power of the engines of the mechanisms for changing the reach of such arrows is spent only on overcoming friction in the arrow hinges, rolling the ropes over the blocks and overcoming wind and inertial resistances. Usually a small part of the power is spent on a small lifting and lowering of the load due to the deviation of its trajectory from the exact horizontal line and on overcoming the unbalanced part of the moment from the weight of the boom.

Figure 3.14 - Articulated boom with a profiled trunk and a flexible guy
A large number of schemes of booms with horizontal movement of the load with a change in reach have been proposed and implemented. Below are four schemes that have received the most widespread use.

The first scheme is articulated arrows with a profiled trunk and a flexible brace (Fig. 3.14). The boom consists of boom 3, trunk 1 and cable guy 2. The curved part of the trunk is profiled so that the horizontal movement of the load is ensured. The trajectory of the end of the trunk depends on the position of the cargo rope. If the rope is parallel to the axis of the arrow, then the end of the trunk moves horizontally. With the help of such an arrow, it is possible to obtain the closest approximation of the trajectory of the movement of the cargo to the horizontal when changing the departure.

The second scheme is articulated arrows with a straight trunk (Fig. 3.15) and with a rigid or flexible brace.

Rigid trunk brace, having a sufficient width in the lower part, significantly reduces the twisting of the arrow under the action of inertia forces applied to the end of the trunk, and keeps the trunk from tipping over in the event of a load break. Due to these properties, a rigid guy is widely used in high-speed portal cranes and cranes.

Figure 3.15 - Articulated boom with a straight trunk and a rigid guy line.
with a large load capacity (75-100 tons). The lifting capacity of floating cranes equipped with jibs of this type reaches 350 tons.

When the trunk is flexible, the weight of the arrow is reduced, but the risk of twisting the arrow and tipping over the trunk increases.

The design of the boom with an additional hinge, which ensures the rotation of the trunk in the transverse direction, has been developed. The brace of the trunk in this arrow is made in the form of one branch of the rope.

When transverse forces occur at the end of the trunk, the latter rotates without twisting the arrow.

The disadvantages of arrows with a straight trunk include a large length of the trunk, a large weight and a large windage in the presence of a rigid brace.

The third scheme is arrows with equalizing chain hoists. Such arrows provide the movement of the load along a line close to the horizontal. To reduce the length of the cargo rope, shortened leveling chain hoists are sometimes used (Fig. 3.16).

Arrows with leveling pulleys are light, easy to manufacture, easy to install and allow you to easily lay them in the stowed position.

Figure 3.16 - Boom with a shortened leveling chain hoist
The disadvantages of these booms include the large length of the ropes from the load to the boom head at low overhangs and, as a result, a large swaying of the load, as well as increased consumption of cargo ropes due to their large length and additional wear from rolling over blocks when the overhang changes.

The fourth scheme is booms with leveling blocks located on a swinging lever and pulling the cargo rope when the departure changes (Fig. 3.17). The trajectory of the movement of the load of such arrows deviates significantly from the horizontal. The improvement of this trajectory usually causes a significant complication of the boom device. Balancing the own weight of the arrows in all four schemes is achieved by a movable counterweight, which is located on a swinging rocker arm connected by a rigid rod to the arrow, or on a cable suspension, an arrow connected to the arrow.

Figure 3.17 - boom with leveling block

3.7 Departure change mechanisms

The mechanisms for changing the outreach of portal cranes must have a rigid kinematic connection with the boom in order to exclude spontaneous movements of the latter under the action of horizontal forces (wind, inertia forces, deviation of cargo ropes from the vertical, etc.).

The main types of departure change mechanisms are: rack and pinion (Fig. 3.18, a) with gear or pinion rails; screw with a rotating nut (Fig. 3.18, b) or with a rotating screw, hydraulic (Fig. 3.18, c), sector (Fig. 3.18, d); sector-crank (Fig. 3.18, e) and crank, in which the connecting rod is connected directly to the boom or to the rocker (Fig. 3.18, f).

Figure 3.18 - The main types of departure change mechanisms: rack and pinion; b - screw; c - hydraulic; e - sector-crank; e - crank.

Of the above types, the rack mechanism is the lightest in weight and simple to manufacture and is increasingly used by crane manufacturers.

The screw mechanism is not heavier than the rack and pinion mechanism, but it is more difficult and expensive to manufacture and requires careful maintenance and monitoring of the state of the nut and screw threads during the operation of the cranes.

The hydraulic mechanism can provide very smooth starts and stops of the mechanism, but it is complicated and expensive to manufacture. During operation, it requires qualified care and supervision.

The sector mechanism is bulky, heavy and difficult to manufacture.

The sector crank mechanism is intermediate between the sector and the crank mechanism, it is simpler and lighter than the sector mechanism.

The crank mechanism, provided that the extreme positions of the boom correspond to the dead points of the mechanism, is reliable and safe in operation, since it does not require end protections and excludes the possibility of the boom falling or tilting onto the crane when it goes beyond the extreme positions. By weight, this is one of the heaviest mechanisms.

3.8 Travel mechanisms

3.8.1 Rail travel system.

In the vast majority of modern portal cranes, the movement mechanisms are carried out with individual drives for each drive trolley. Synchronization of drives is not carried out electrically, but due to the rigidity of the portals.

The number of driving wheels is usually 25-100% of the total number of driving wheels. A small number of drive running wheels is permissible only when the crane moves along a strictly horizontal path laid on a reliable foundation, and with a small windward area of ​​\u200b\u200bthe crane and load. If these conditions are not observed, slipping of the wheels of lightly loaded crane supports may occur.

There are a large number of different chassis designs. The most common designs with 16 running wheels - 8 drive and 8 idle, but they can be arranged in different ways. The first option involves only two drive carts located diagonally on the legs of the portal. The engine of each cart drives four drive wheels. In the second version, there are four drive bogies located under all four legs, the engine of each bogie drives two drive wheels.

Installing two engines of high power with appropriate control equipment is cheaper than four engines of the same total power, but with four drive wheels from one engine, a very long kinematic chain is obtained (10 gears and a worm pair). With two drive wheels from one engine, the kinematic chain can be significantly shortened (3 gears and a worm pair), which largely compensates for the additional costs of installing four engines instead of two.

With two engines, the drive is less reliable, since if one of them fails, the crane cannot move, while temporary operation on three engines instead of four is quite possible. With two engines, there are often cases of overloading one of the engines when working on uneven crane tracks, when the support on which the other engine is installed is switched off due to uneven subsidence of the tracks.

Heavy gantry cranes use undercarriages with a large number of running wheels. Figure 3.19 shows such a trolley of a 75 ton portal crane of the PTO plant named after. Kirov on 10 wheels with two

Figure 3.19 - Undercarriage of a 75-ton crane of the PTO plant named after S. M. Kirov
engines. A characteristic feature of this trolley is the availability for inspection or repair of any running wheel. These wheels are mounted in removable corner boxes, each of which is attached to the frame with two bolts. To remove any wheel (bogie), it is necessary to release it from the load using a hydraulic jack and a special device, after which it is enough to lift the wheel by 2-3 mm and roll it out to the side.

3.8.2 Pneumatic wheel running system.

Kranbau Eberswalde has made its cranes mobile. The process of moving away from the shackling system on rails began in cooperation with I-BAU from Hamburg with crawler cranes, with the first mobile container cranes of the FEEDER SERVER system in Ho Chi Minh City and with the production of two mobile conveyor cranes. Mobility is now also provided for the high performance crane, the Articulated Harbor Crane AHC.

The design of the AHC rail-mounted crane with extremely high handling capacity, safety and reliability is adapted to market requirements based on the proven equipment of the Kirova brand travel mechanism.

In order not to interfere with the traffic flow in the port, the advantages of a high portal are retained. Optimum loading into wagons is possible by spanning two or more rail tracks. Two chassis options are available:

▬ for driving in a straight line and a small frequency of movement in a curve. Chassis based on a modified design of the RTG type crane (Fig. 3.20).

Figure 3.20 - Pneumatic wheeled undercarriages that provide movement along a straight path
▬ For complete flexibility, a running gear offering the ability to turn in place. Proven equipment of the Kirov arch, reused in the field of means for transporting heavy loads. A novelty on a global scale - FEEDER server ". (Fig. 3.21).

Figure 3.21 - The FEEDER SERVER running system provides full mobility: a - front view; b - side view
Advantages of the FEEDER SERVER system:

▬ Light steel supporting structure and crane trolley;

▬ Standardized machine units;

▬ Modular drive units;

▬ Short installation time;

▬ Low investment costs;

▬ Low operating costs;

▬ Mobility;

▬ High efficiency;

▬ Low noise level;

▬ Versatile application possibilities.

3.9 Portal structures

The variety of design of portals is explained by the variety of requirements for portals and cranes, the difference in the traditions and experience of crane-building enterprises and the little knowledge of the boundaries of the rational use of portal structures. Portals differ in the type of attachment of supports to the upper crossbar (hinged and rigid) in the number of connections with the part (three- and four-support) in the way the structure is formed (lattice, frame (see Fig. 3.22 a, b) frame-tower (Fig. 3.22 , c), frame-diagonal (Fig. 3.22, d), according to the number of attachments of supports to the upper crossbar: two- (Fig. 3.22, 6) and four-column (Fig. 3.22, a), etc. The design of the portal is affected by type of slewing ring: on a multi-roller circle, on a rotary column and on a ball slewing circle.

Figure 3.22 - Portals: a - four-post frame; b - frame two-column; in - frame-tower; g - frame-diagonal
Four-column portals are more metal-intensive than two-column portals, but are less prone to deformation, which is important for erection cranes. In the designs of cranes produced in recent years, frame-tower portals are widely used, in which a cylindrical (Fig. 3.22, c), cylindrical or pyramidal tower is attached to a frame

Figure 3.23 - Schemes of portals: a - single-track; b - double-track; c - three-way

Figure 3.24 - Frame four-column portal of a box-shaped design
designs. According to statistics, the use of double-column and frame-tower portals is expanding, while four-column portals are declining.

3.10 Rotation mechanisms

The gantry crane slewing mechanism consists of a slewing device supporting and centering the slewing part, and a drive that rotates the slewing part. Depending on the type of slewing device, cranes are distinguished on a column and on a turntable.

Slewing devices for cranes on a column.

Portal cranes on the column are used in two types - with a fixed or rotary column (Fig. 3.25).

In the first case (Fig. 3.25, a), the column serves as a continuation of the portal, and the turning part rotates around it. The weight of the rotary part with the load is perceived by the thrust bearing at the top of the column, and the overturning moment - by the radial supports at the top of the column and at its base.

In cranes with a swivel column (Fig. 3.25, b), the latter is integral with the swivel part. In this case, the weight of the rotary part with the load is taken by the bearing located at the bottom of the column, and the overturning moment is taken by the radial supports at the bottom of the column and in the upper part of the portal. Cranes with a rotary column are the most widely used.

Figure 3.25 - Scheme of crane support on a column: a - with a fixed column; b - with a rotary column

Slewing bearings for cranes on a turntable.

Portal cranes on the slewing circle are used in two types: with wheeled and with roller (or ball) slewing devices.

A wheeled slewing device usually has four supports, and depending on the load, either one wheel or a two-wheeled balancing cart is installed in each support.

Roller slewing devices are made with conical or cylindrical rollers (Fig. 3.26). In the first case, it is a large tapered roller bearing, in which both rings are machined into a cone so that the generatrix of these cones and the axis of rotation of the rollers intersect at one point on the axis of rotation of the turning part, while the rollers roll along the rails without slipping. In the second case, the rollers have a cylindrical shape, the surfaces of the rings are two planes, and the rollers roll with sliding.

Ball slewing devices. Two types of ball bearings are used: those that perceive only vertical load and those that perceive vertical load, horizontal forces and overturning moment. In all cases of using ball devices for their normal operation, it is necessary to provide a significantly greater rigidity of heads, portals and turntables than with roller and wheel devices.

Figure 3.26 - Schemes of roller slewing devices: a - with conical rollers; b - with cylindrical rollers

3.11 Lifting mechanisms

In grab cranes, the most common are lifting mechanisms, consisting of two independent winches - lifting and closing, having neither mechanical nor electrical connection, each of which is controlled by its own controller. The handles of the controllers of these winches are installed so that they can be controlled separately or together (with one hand).

Winches are made from separate unified blocks (electric motor, brake, gearbox, drum, main bearing of the drum, couplings), which are installed on a common frame. This design of winches ensures their convenient assembly with almost no adjustment work, and the interchangeability of individual blocks greatly simplifies the organization of repair work.

As can be seen from Figure 3.27, the axes of the electric motor, the input and output shafts of the gearbox and the drum of these winches lie on the same straight line. Such a so-called coaxial scheme has a number of significant advantages compared to a scheme with parallel axes, namely: smaller winch dimensions in the plan, the ability to install two winches side by side while maintaining easy access to all their parts for maintenance, a significantly simplified design of winch frames, reduction gear gearbox weight.

Figure 3.27 - Grab crane lifting winch

Hook crane lifting mechanisms. Figures 3.28 and 3.29 show the winch of a 10 ton hook gantry crane. It consists of the same separate blocks as the clamshell winch (Fig. 3.27), but unlike it, here the engine axis and the drum axis are parallel to each other. The speed control required for hook cranes is carried out electrically.

Figure 3.28 Hook crane hoist device: 1 - brake, 2 - drum, 3 - engine, 4 - gearbox.

Figure 3.29 - Kinematic diagram of a winch with a microdrive

For assembly gantry cranes used in shipbuilding, ship repair, construction and installation works and in other similar cases, a wider range of speed control is required. In this regard, winches with the so-called microdrive (Fig. 3.29) are widely used on mounting cranes.

3.12 Working equipment

Work equipment includes; spreaders, double-jaw grabs, electromagnets, multi-jaw grabs, hook hangers, traverses.
A
b

V
G

Figure 3.30 - Working equipment: a - spreader; b - double jaw grab; c - electromagnet; g - multi-jaw grab

A
b

Figure 3.31 - Working equipment: a - hook suspension; b - traverse

3.13 Cabins

Control cabins. Portal crane control cabins (Fig. 3.32 and 3.33) are usually located on the swing frame, in front of it. To ensure good visibility from the cab, it is most convenient when its axis coincides with the axis of symmetry of the crane.

A seat for the crane operator is installed in the control cabin and control devices and equipment for lighting the crane (commander controllers, transformers, lighting panel, etc.) are placed in the rear part of the control cabin.

Figure 3.32 - The control cabin of the crane ZPTO them. S. M. Kirova

Figure 3.33 - Cabin version

management
Electrical equipment that can be a source of heat (resistors, starters, switching equipment), as a rule, is located in the cab of mechanisms. The floor of the control cabin must be covered with a rubber mat.

Cabins of mechanisms. The mechanisms of the rotary part of portal cranes are located in closed, waterproof, unheated cabins (Fig. 3.34). The mechanism for changing the reach of the jib is often installed in a special cabin placed on the platform above the cabin of the mechanisms or

Figure 3.34 - Cabin of crane mechanisms ZPTO them. S. M. Kirova

in the upper part of the frame, and in cranes with a column - inside the latter. In addition to mechanisms, panels and resistances are placed in the cockpit.

An I-beam is usually bolted to the frame of the machinery cab overlap, along which a hand truck with a hoist moves to service the mechanisms and equipment installed in the cab.

3.14 Safety devices

The main safety device of the gantry crane is the load limiter device, which consists of a force-measuring cell, a measuring amplifier and an electronic device for receiving signals, showing through the indicator device (light board) the values ​​of the load lifted by the gantry crane. The most important task of the electronic device of the lifting capacity of the crane is to prohibit the overload of the portal crane in the event of the lifting of excessive loads that exceed the permissible lifting capacity of the crane and allows only lowering the lifted load to the ground.

Other important crane safety devices include an anemometer, which continuously measures and records wind pressures. The principle of operation of the applied anemometer is based on a blade device for measuring wind speed. When the wind speed value set in the device is reached and when the permissible wind speed value is exceeded, the anemometer device first issues an alert, warning signal, and then issues a command to stop movements and turn off the crane. If the wind pressure exceeds the pressure value taken into account when designing the crane, the anemometer device activates the rail anti-theft grippers and stops the crane travel mechanism.

The portal crane has a special system of electrical protection of the electrical devices and equipment used, which, in the event of a network failure, serves to protect electrical devices and equipment.

Further protection and safety devices for the crane include various blocking devices, mechanical protection devices, limit switches and limit switches, the operation of which occurs under the action of and together with the programmable control system of the crane drive devices, they mainly play the role of protecting mechanisms and components of the crane and in the event of extreme or emergency situations, they limit the extreme positions or issue a signal to prohibit the performance of a particular function.

In the event of an emergency situation on the portal crane, its operation can also be stopped by the emergency stop button from the crane operator's cab, which, in turn, also means a kind of protective measure to protect the crane devices.

In the interests of safe operation of the portal crane, the following safety and signaling devices are used on it:

Mechanical protections:

▬ electric rail anti-theft grab device

Crane electrical protection devices:

▬ touch protection system

▬ overcurrent protection system

▬ protection against short circuit currents

▬ zero voltage protection

▬ internal lightning protection

▬ crane overload protection

▬ protection against zero position of controllers

▬ emergency switches

▬ protection against starting in the closed state of rail anti-theft grippers (travel mechanism, portal)

Limit stops:

▬ Limit switches for the upper and lower limit positions of the load

▬ Longest and shortest reach end positions

▬ Collision limiter for two cranes traveling on the same crane runway

Measuring devices used on the crane:

▬ voltmeter

▬ ammeters

▬ wind pressure anemometer

▬ load meter (load limiter)

Crane alarms:

▬ sound and light alarm when moving the crane

▬ signal horn

▬ alarm siren

▬ indicator device (display) and operator panel on the crane control panel (for the purpose of the function of checking modes and operating parameters, indicating errors and system malfunctions).

The Baltiysky Zavod in St. Petersburg, one of the oldest Russian shipyards, which experienced hard times until recently, is now busy with work. Two sisterships of the already launched Arktika, the world's newest and most powerful nuclear-powered icebreaker, are being built here. The names of the future ships are "Ural" and "Siberia".

What did not learn in the USSR?

Step by step, the hulls of icebreakers are built up by newly attached sections, each of which has impressive dimensions and weight. Such work cannot be done without high-capacity gantry assembly cranes. They are called portal not because they work in the port (as some people think), but because they are installed on the portal - a platform on widely spaced supports rolling along rails. The rails are laid along the sides of the icebreakers under construction, and cranes, moving from place to place, supply more and more new parts to the construction site. At the shipyard you can see the entire history of portal cranes in our country over the past decades. Here is an experienced Soviet-built crane, worked out at the Kirov plant. Here is a fresher car - a crane made in Finland. This is already the era of the extinction of domestic production: then we thought that we would buy the best abroad, and our shipyards and ports were given to the products of German and Finnish companies. And here is a novelty of recent years - the SMM-4500 crane. This machine, outstanding in many respects, was made by the St. Petersburg company SMM, which at one time grew out of a repair enterprise. The production of portal cranes returned to Russia.

The construction of a nuclear icebreaker is carried out with the help of giant portal cranes, including the Russian novelty SMM-4500 with a lifting capacity of 100 tons

“Cranes of this class of load-carrying capacity were never made in the USSR,” says Alexander Zhuravlev, chief designer of the SMM company, “so we can talk not about the return of the production of portal cranes to Russia, but about a qualitatively new step in this area. The maximum load capacity of our SMM-4500 is 100 tons, the outreach is 60 m. You can count on the fingers of world manufacturers who know how to build such equipment - mostly Finns and Germans. More China lately.”

Almost like the subway

The point, in fact, is not in the numbers as such, but in the requirements of the customer. “The SMM-4500 is the only crane in our company that, thanks to the reach of the boom, can deliver cargo not only to the near side of the ship under construction, but also to the opposite side,” explains Nikolai Drozdov, head of the workshop servicing portal cranes. “We can say that we are able to fulfill the current order precisely because we have such a machine.”

SMM manufactures both erection (mainly for shipbuilding) and transfer cranes (for work in the port). The diagram shows how the SMM-4500, an erection portal crane of the Baltic Plant, is arranged.

The work of the crane takes place somewhere up there, at eye level, only the lower parts of the portal supports. The machine stops, transfers the load, gives a signal and slowly rolls to a new position. For an assembly portal crane, unlike a port reloading crane, speed is not so important. Each of the four supports is placed on eight steel wheels; they are distinguished from the railway ones by the presence of a second flange. The rails are also special, crane rails are wider and more massive. Eight wheels are distributed between four bogies, which are connected to the support by a pivot-balancing system. “No matter how accurately you lay the crane track,” says Alexander Zhuravlev, “some irregularities will still remain. If they are within the framework of GOST, it’s okay, however, by connecting the wheeled bogies to the support not rigidly, but through a pivot-balancing system, we enable our chassis to work out these irregularities. For example, do not allow the wheel to hang over the rail, in which the remaining wheels will experience an off-design load. The wheels are driven by electric motors, which are mounted directly on the carts. The power supply system on the SMM-4500 resembles, oddly enough, the one used in the subway. As you know, the subway electric train receives energy from the contact rail with the help of current collectors installed on wheeled bogies. Here, next to one of the rails, a trench was made, covered for safety with flexible rubber curtains. Three current-carrying busbars are laid inside the trench. With the help of a special current collector, the crane moves the shutter and removes a three-phase current of 380 volts with a shoe contact.

steps-petals

The engine room, electronics and automation, the crane operator's cabin - all this is located at the height of a 12-13-story building. The way there is exclusively on foot. First, you need to climb the steep, ship-like ladders to the upper platform of the portal, and then climb the spiral staircase inside the column on which the crane stands. While you are walking up this staircase, you do not raise your eyes - it is scary to think how many more steps there are ahead. When you go down, it seems that the steps below turn into the petals of a rotating flower. This optical illusion makes me dizzy. Phew! Upstairs, inside the platform of the engine room, there is a large round hall where the mechanisms for turning the crane installation are installed. The winches of the main and auxiliary lifting are located one floor above. The ends of the cables disappear into a crack in the ceiling. Above the engine room, on the rack, a rack-and-pinion mechanism for changing the reach of the boom is installed.

The resemblance to birds - a crane or a heron - is given to portal cranes by an articulated boom system. Another element is attached to the main boom on a hinge - it is called the “beak”, “goose”, and sometimes the “trunk”. Such a system was invented in the late 1930s in Germany. When the main boom changes reach (that is, it rises or falls), the load suspended from it also inevitably changes height. In an articulated system, the “trunk” performs a compensating movement, holding the load at a given height. This does not require the work of a lifting winch, that is, no extra energy is wasted. Both during installation and reloading work, keeping the load at the same level is an important safety factor.

The crane operator's cabin is located at the height of a 12-13-story building, and the way there is not easy: first, climbing steep ladders, then many steps along a spiral staircase.

And finally, the cabin, from which all this machinery is controlled. Immediately pay attention to the panoramic glazing. The cockpit offers an excellent view of the territory of the famous plant, the ships under construction and the entire Vasilyevsky Island. Somewhere in the distance, the still unfinished tower of the Lakhta Center rises. At the workplace of the crane operator (more precisely, the crane operator - giant cranes at the Baltic Shipyard are mainly operated by ladies) there is a comfortable chair, two joysticks on the sides, and a parametric display opposite.

“Comfort and ergonomics of the cab are priority tasks for us,” says Alexander Zhuravlev, “as they are directly related to work safety. In the old days, little attention was paid to this - there were uncomfortable seats in the cabs, on which it was hard to work for hours, there were no air conditioners. Cranes were then controlled using a relay-contactor system, and the movement of the controller required considerable effort from the crane operator. Now everything is different. The workplace is equipped with a comfortable ergonomic chair. Frequency control of electric drives allows the crane operator to perform smooth and precise movements using two joysticks. To increase the safety of work, we install special sensors that prevent, for example, the collision of booms - and this sometimes happens, especially when handling cranes are operating in the port. On the other hand, hanging the entire crane with sensors would also be wrong: it simply will not be able to work due to the constant reinsurance of automation. Still, the control of the machine is still largely in the hands of a person, not a computer. Although the emergence of unmanned cranes is probably a matter of the near future.”

At the virtual abyss

SMM-4500 is no longer the largest erection crane produced in Russia. The machine, built for another legendary shipyard - SevMash in Severodvinsk, has characteristics that, perhaps, have no equal in Europe. Load capacity - 160 tons, boom reach - 80 m, lifting height - 75 m. “These figures may not impress an uninitiated person,” Alexander Zhuravlev explains, “but behind every meter of increase in boom reach there is a most difficult engineering task. The longer the "arm" of the crane, the more difficult it is to balance it. A heavier counterweight is needed, but the total mass of the machine cannot be increased indefinitely. You can't save on reducing the weight of the portal: it provides stability and should not be very light. The main way is to reduce the mass of the boom system while maintaining high strength. This is work with new materials, steel grades, welding technologies.”

Next to the new Russian gantry crane SMM-4500, which has been in operation since 2014, machines made in the USSR (left) and Finland (right) are working on the construction of nuclear icebreakers.

At SMM, cranes are designed using 3D modeling. The model created on the computer is tested in software environments that simulate different loads. If weaknesses are identified, the model is sent to the designer for revision, then returned to new virtual tests. There can be many such iterations. The virtual revolution has not bypassed the training system for crane operators and service personnel. SMM is developing a VR simulator that allows not only to master the control of a crane in an extremely realistic mode, but also to actually see each of its nodes, to understand how it works. Putting on virtual reality goggles and picking up a joystick, I tried - no, not to work on the crane, but simply to travel on it. And here I was at a high altitude, next to the railing of the fence. And I was scared: the railing was virtual, and the height ... the height was frightening. It was a very strange feeling.