Full slewing gantry crane. Portal crane and its role in the work of the port. Varieties of portal cranes

29.03.2022

Gantry cranes

Portal jib cranes are the most common type of concrete placing crane used in hydraulic engineering to supply buckets of concrete mix from an overpass to building blocks. Being installed in the main mechanization area, these cranes serve all the preparatory work of the concrete complex, and are also used in open areas for servicing the enlarged assembly and reloading operations.

The portal-jib crane is a supporting structure - a portal moving along rail tracks with a swivel crane part installed on it. The portal is the main difference between portal jib cranes and jib cranes of other designs. The rotary crane part is unified for installation on various mobile support structures (Fig. 31). The crane portal can block several railway tracks (one-, two-, three- and multi-track portals).

The lifting capacity of building-type gantry cranes reaches 20/30 g at a reach of 50/20 m, which ensures the supply of concrete mix in tubs with a capacity of 6 m3.

The depth of lowering the hook below the head of the crane rail depends on the height of the concrete trestle and reaches 70 m or more; lifting height of the hook above the crane rail 36 m.

Portal-jib cranes of building type are made only with hook cranes. Their portals have a large height, since under them reinforcing trusses and other construction goods of large dimensions can be transported along the overpass.

Construction cranes have the same high lifting speeds as transfer cranes. However, their turning speeds and departure changes are somewhat less than those of reloading ones, which is necessary to reduce the swaying of the load, which usually hangs on long ropes.

The lifting capacity of special type gantry cranes reaches 100 tons and a reach of up to 50 m.

A general view of the construction portal-jib crane is shown in fig. 32. The main components of the crane are: boom, frame, swivel frame, slewing device, portal, mechanisms for rotating the swivel part, lifting the load and changing the reach, the crane control cabin.

The movement of the crane is carried out by electric motors located on the drive trolleys of the portal, from where the rotation is transmitted through the gearbox to the wheels. The individual drive is convenient in operation and repair and is not so sensitive to damage to the portal.

Rice. 31. Schemes of portal-jib cranes:
a - portal; b - semi-portal; c - on a triangular stand (sloping); g - moving along the portal; d - clamshell with a bunker; 1 - loading hopper; 2 - conveyors; 3 - sleeves

Taking into account that these cranes in the conditions of hydraulic engineering construction are usually installed on high concrete racks, and also bearing in mind the large windward area of the crane and cargo, the number of driving wheels of the crane is normally taken equal to 50%, and sometimes 100% of their total presence, which eliminates the risk of slipping.

On fig. 33 shows typical undercarriages of portal-jib cranes with a lifting capacity of 3-25 tons of the plant named after. Kirov. The portal leg of the three-ton crane rests directly on the trolley; for five-ton cranes, the pressure of the portal leg is transmitted to the same trolley and additionally to the third wheel; for 10- and 15-ton cranes, the portal leg through the balancer rests on the drive and idle bogies.

Rice. 32. Construction portal-jib crane: o - with a curved trunk and a flexible brace; b - with a straight trunk and a rigid brace

Rice. 33. Types of undercarriages of portal-jib cranes: a - two-wheeled; b and e - three-wheeled; in - four-wheeled; g - eight-wheeled

To ensure the correct movement of the portal along the paths, it is necessary to observe:
a) one-line installation of the strips of each side of the portal and the parallelism of the lines of the wheels of both sides of the portal to each other;
b) equality of diameters of all driving wheels;
c) the correct profile of the wheels. Failure to comply with these conditions leads to a violation of the geometry of the crane portal and to premature wear of its movement mechanism.

Portal boom cranes are distinguished mainly by the arrangement of booms, which are the most characteristic elements that determine both the design of cranes and their performance.

Boom devices, as a rule, have a horizontal movement of the load and are made with straight or articulated booms of various types.

Articulated booms with a balanced mechanism for changing the reach ensure the horizontal trajectory of the movement of the load suspended on the hook, which at the same time creates conditions for the balance of the load relative to the mechanism itself.

The most common are articulated arrows with horizontal movement of the end blocks, made according to one of the following schemes: a) an arrow with a flexible jib brace (see Fig. 32, a) and b) an arrow with a rigid jib brace (see Fig. 32.6 ).

The booms are supported by the lower hinges, which connect the booms to the swivel frame, and the boom rods, which connect the booms with the mechanisms for changing the reach and balancing them with counterweights.

For inspection and maintenance of the jib end blocks, the booms are equipped with a ladder with railings and a platform.

Crane booms are balanced by movable counterweights, which are selected so that the moment created by their weight relative to the axis of rotation of the lever, for all positions of the booms, is equal to the moment on the same axis created by the total weight of the booms (boom, jib and guy). With this arrangement, the arrows are always in a state of indifferent equilibrium, and little effort is required to change their projection.

Since when changing the angle of inclination (departure) of articulated booms, the load moves almost horizontally, when performing this operation, additional energy is not expended on lifting the load.

The use of articulated and balanced booms makes it possible to easily and safely change the reach of a crane with a load, using this movement as the main working one, along with lifting and turning movements.

Departure change mechanisms usually have a rigid kinematic connection with the boom device in order to exclude spontaneous movements of booms under the action of horizontal forces (wind, inertia forces, deviation of cargo ropes from the vertical, etc.).

Rice. 34. Types of departure change mechanisms

On fig. 34 shows the main types of departure change mechanisms: rack (a) with gear or pinion rails, screw (b) with a rotating nut or screw, hydraulic (c), sector (d), sector-crank (e) and crank-rod (e), in which the stepper is connected directly to the arrow or to the yoke. The rack and pinion mechanism is the simplest of all types, easy to manufacture and is increasingly used.

The rotary part of the crane (Fig. 35) rests on a slewing device in the form of wheel, roller or ball bearings with a centering pin (column) fixed in the metal structure of the portal. On the frame of the rotary part there are lifting winches, mechanisms for turning and changing: takeoff, electrical equipment and a cabin with a control panel.

The turning mechanisms of portal-boom cranes consist of a turntable supporting and centering the turning part of the crane, and a drive that rotates the turning part.

Rice. 35. The rotary part of the portal-jib crane on the turntable:
1 - lever with boom counterweight; 2 - rack-and-pinion mechanism for changing the departure; 3 - winch; 4 - turning mechanism

Depending on the type of slewing device, cranes are distinguished with a device mounted on turning circles (wheel, roller and ball valves) and mounted on rotary columns. Slewing mechanisms usually have torque limit clutches and open controlled brakes. Recently, the hydraulic drive has also been used.

The lifting mechanisms of ortal-jib cranes are very diverse. The main parts of the lifting mechanism are load gripping devices, rope pulley blocks, drive winch, control system and signal and safety devices. The layout and design of load handling devices, winches and other units, as well as the rope reeving scheme depend on the lifting capacity, the purpose of the crane and the type of its boom device.

All gantry cranes are equipped with load limiters and boom departure indicators.

Portal-boom full-rotation self-propelled cranes are most widely used when laying concrete mix from concrete-carrying racks in the middle and high parts of structures. These cranes are especially important when combining construction and installation work in the construction of hydroelectric structures, where, along with concrete laying, a large amount of work is carried out on the installation of metal structures of the switchboard compartment and embedded parts of hydraulic units. With the correct location of the cranes in relation to the shield compartment and suction pipes, it seems possible to serve them with the entire front of laying the concrete mix and installation work on the power plant building.

The installation of the crane must be carried out under the guidance of an experienced specialist according to a pre-designed project for the organization of installation work. The method of mounting depends primarily on the mounting means available, their load capacity and lifting height.

During the operation of gantry cranes, the main attention should be paid to the condition of the rail tracks, compliance with the established rules for lifting the load, ensuring the stability of the crane in the idle state and compliance with safety regulations. During the operation of cranes, a system of preventive and routine repairs, regular inspection of cranes, adjustment and lubrication of individual components and parts in accordance with the factory instructions, systematic supervision of the state of the supporting structure of the crane and its mechanisms are mandatory.

Checking the stability of the portal-boom crane, raising (or lowering) the maximum load, is carried out taking into account the influence of inertial forces and wind pressure directed towards the load with the design head for the operating state of the crane.

For a crane without a load, the stability check is carried out taking into account the action of the wind with the design head for the idle state of the crane.

To category: - Masts, chevres, portals and mast-jib cranes

A gantry crane is a material handling equipment with a large lifting capacity. A massive swivel structure is installed on the portal, which moves along the rails. This technique is used in open areas, because it has a large weight and large dimensions. Depending on the design, portal cranes have different applications.

Use of portal cranes

Maskus is a portal for the sale of equipment, where you can find various equipment for warehouse work. The catalog presents a variety of container handling equipment and other warehouse machines that allow you to increase work efficiency. New and used warehouse forklifts, stackers and order pickers without running time and used ones can be bought and sold through our portal.

Features of port portal cranes

Mobile port cranes are used for containers and other heavy loads. Among their features:

load capacity - 1.5-2 tons;
departure - 15-40 m;
availability of replacement equipment.

As a rule, machines with a lifting capacity of more than 3 tons are equipped with hooks for piece cargo and grabs. Grabs are used to a limited extent, most lifts are equipped with a hook only. The load capacity usually remains constant on all departures.

Among modern mobile cranes, universal models are most in demand, which are suitable for any port work. They are characterized by high efficiency and productivity, cope with heavy loads quickly and efficiently.

Purchase and sale of special equipment

Port cranes are complex and expensive equipment, which is indispensable when working in the port. You can find different types of such equipment on the Mascus portal, where both new and used forklifts are available. Offers from individuals and companies will help you find exactly the option that suits you.

You can select equipment by manufacturer, cost, location and other parameters. A special filter will help you navigate in a wide range. Delivery from other countries and across Russia is carried out by partner transport companies. Choose on the Maskus portal advantageous offers for the purchase and sale of special equipment!

3 PORTAL CRANES. DESCRIPTION. CHARACTERISTICS

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 - Portal cranes with a bunker (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 swivel. 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 erection 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 trestle. 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 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 the lifting or lowering of the load when changing the reach require very powerful mechanisms for changing the reach, therefore 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 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 gantry 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 due to the coverage of 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 diversity of the 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

in
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 portal 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 portal 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 start-up 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 runways

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.

Figure 3.1 - Portal crane. General form.

1-way trolley;

3-support rotary device;

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

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.

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.

Figure 3.5 - Portal cranes with a bunker (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 swivel. 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.

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