Rigging, machinery, equipment and rigging. Rigging equipment and lifting mechanisms
2.7.2. Purpose and types of rigging
Rigging is the work of tying equipment units with flexible hangers (slinging), lifting them and transporting them to the installation site. Rigging works are performed using various lifting means and mechanisms, devices and machines.
Equipment and structures are most often transported from the manufacturing plant to the assembly site and along it by rail, less often by road or water transport. The transverse dimensions of goods delivered by rail must not exceed the all-Union dimensions of the outline of the rolling stock. The transportation of oversized cargo is coordinated with the management of the railway in accordance with the rules of the Ministry of Railways.
When transporting non-rail vehicles, goods weighing up to 12 tons are transported by motor vehicles, over 12 tons - on heavy trucks - trailers towed by tractors or a tractor.
To move loads during installation, the most effective use of standard means - tractors, mobile cranes, pipe-layers, forklifts, etc., in the absence of this equipment, use electric winches, mounting blocks, chain hoists, hoists, as well as the simplest devices - sledges, boards and rollers or a metal sheet with a bent front end and loops welded to it for a traction rope.
When performing rigging work, especially when lifting loads, slinging is a very important and responsible operation. Especially carefully it is necessary to tie together large units of equipment with a large mass.
Rice. 107. Classification of rigging equipment
All corners of the equipment, where the slings touch, must be twisted with special safety pads (Fig. 108). Slinging can be divided into two types:
1) by tying the goods with ropes, slings or chains;
2) by tying the slinging ropes on tides, trunnions, legs, eye bolts and other parts specially provided on the equipment for its lifting and transportation.
The most commonly used cargo strapping units (pull units) are shown in Fig. 109.
When slinging, it is important to correctly determine the center of gravity of the load. The slinging must be done so that the center of gravity of the load and the axis of the hook block of the lifting device are on the same vertical.
The mass of enlarged units and units of equipment should not exceed the carrying capacity of the lifting equipment available at the assembly site, and the overall dimensions should not exceed the dimensions of the assembly openings. When installing large and heavy equipment, two or more cranes can be used simultaneously. Such work is carried out with the written permission of the chief engineer of the SMU or the head of the site under the guidance of an experienced specialist.
2.7.3. Rigging equipment and accessories
Rigging means and devices include steel and hemp ropes, chains, slings, traverses, grips, blocks, pulleys, hoists, winches, jacks.
Slings (fig. 111) are called pieces of ropes or chains, connected in rings or equipped with special suspension devices that provide quick, convenient and safe fastening of the load. The number of sling branches on which the load is suspended is selected depending on the weight of the load and the diameter of the rope.
In order to increase productivity and safety of work, semi-automatic slings are used (Fig. 112), which allow unstitching of the raised load without rising to a height. To sling the load, the upper loop of the rope 1 is thrown onto the crane hook, and the load is wrapped around the two freely hanging ends of the sling rope. The rope loops with thimbles 3 are put on the locking pin 6, which is pulled to the left by the cable 4 for this. After inserting the loops into the bracket 7, the cable is released, the pin, under the action of the spring 5, locks the loop and the load slinging is completed. To protect the rope from damage during bends on the sharp edges of the lifted load, special inventory pads 2 are attached to it, which, if necessary, can be moved along the rope.
Rice. 108. Installation of safety pads under the sling when tying equipment units:
a - wooden; b - from a cut pipe with welded grandmothers;
c, d - bent from pipes; d, f - curved sheet metal
Rice. 109. Pull knots:
a - straight line; b - reef; c - knitting into a loop; g - bramshkot;
d - dead loop; e - bleached; g - double bleached;
h - sea knot; and - double sea knot; k - carpentry knot (stranglehold); l - noose with an overlap; m - bayonet; n - half-bayonet
To release the slings, it is necessary to loosen the tension of the cargo rope and pull on the cable, which, overcoming the force of the spring, will compress it and pull the pin to the extreme left position. This will release the free end of the sling (loop).
In addition to semi-automatic slings, semi-automatic slings are also used for remote slinging of the load raised to the design position.
To connect the ends of the ropes or form a loop, clamps or clamps of various designs are used (Fig. 113).
Apply at least three clamps. The distance between them is usually taken at least three. The distance between them is usually taken at least 6 diameters of the rope. The nut on the rods of all clamps should be tightened with the same force using torque wrenches so that the compressed diameter of the rope is 0.6 of its original diameter.
Rice. 111. Slings: a - simple; b - with one loop; c - with two loops; g - universal; d - lightweight with a loop; e - lightweight with a hook
Rice. 112. Semi-automatic slings: a - general view; b - slinging diagram; c - a bracket with a semi-automatic lock; d - strap for lifting pipes and shafts; 1 - rope loop; 2 - inventory linings; 3 - a loop with a thimble; 4 - pull-back cable; 5 - spring; 6 - locking pin; 7- bracket
Rice. 113. Clamps for fastening steel ropes: a - forged; b - arc
The ends of the ropes are fixed with clamps, usually through the thimble, which serves to hook onto the hook and protects the rope from flattening and delamination of strands and wires at bends. The thimbles are stamped from sheet metal or made from cast iron.
The clamps should be placed on the rope so that the tightening nuts are located on the side of the working branch of the rope. This provides the latter with straightness, and the end tending to slip will be better clamped.
For tensioning steel ropes in rigging, screw ties (towbars) are used. The brace is a frame with two screws - with right and left threads. As the frame rotates, the screws move closer or apart.
When reloading and transporting sheet and section metal, pipes, refractory blocks and other piece goods, grippers of various designs are used (Fig. 114).
Rice. 114. Grippers: a - eccentric for transporting sheet steel; b - tick-borne; c, d - semi-automatic for lifting, respectively, light and heavy (reinforced concrete) columns; d - friction sling for the installation of reinforced concrete columns; e - for transportation of rectangular goods weighing 10 tons
Rice. 115. Traverses: a - for slinging cargo at four points; b - equal-armed; c - for installation with two pulley blocks
For transportation of bulky and long loads, traverses are used (Fig. 115). Their main purpose is to protect the lifted elements from the impact of compressive forces arising in them when the slings are tilted. The traverse, designed for slinging the load at four points (Fig. 115, a), consists of a balancing beam 1 with a shackle 2 for the hook of the lifting mechanism and two roller clips 3, suspended from the ends of the beam, with slings 5. In the clips of the rollers there are clamping screws 4, one of which (on the cheek piece) prevents the sling from sliding, and the other (installed at the end of the cage) presses the roller, preventing its rotation. The clamping screws allow the load to be lifted with some inclination, which makes it easier to install it in the design position at an angle.
If the load is lifted by two paired cranes of different carrying capacity (or by two trolleys of one crane), then an equal-arm traverse is used (Fig. 115, b).
The place of the traverse hook is determined by the ratio of its shoulder, taking into account the lifting capacity of each crane.
For the installation of heavy equipment with paired cranes, a balancing traverse is used (Fig. 115, c). The traverse consists of two I-beams 6, connected by cross members 5. At the ends of the traverse there are suspensions 1 for attaching assembly cranes to the cargo chain hoists. Sheet pads 4 are welded from the ends of the traverse. The strapping of the load being lifted is carried out using an automatic gripper 7. The cable 3 for strapping passes through the diverter roller 2.
Blocks are used to lift or move the load, as well as to change the direction of the ropes. Depending on the number of rollers, the blocks are divided into single-roll and multi-roll. Single-sided blocks are usually used as branch blocks and for lifting light loads, multi-sided ones - for lifting heavy loads. The rollers of the blocks rotate on an axle fixedly installed in the cheeks, to which a hook or earrings are attached through a traverse. The blocks are equipped with devices that protect the rope from slipping. Single-spool pulleys are often made with folding cheeks for quick separation of the rope from the pulley without unstitching.
To reduce tractive effort, pulley blocks are used. The polyspast (Fig. 116, a) consists of a fixed block 1 and a movable block 2; block 3 (diverting) serves to divert the runaway branch of the rope, usually associated with the winch drum. Depending on the pattern of the chain hoist, the runaway branch can escape from a moving or stationary block. The number of threads of the chain hoist can be even (Fig. 116, b) and odd (Fig. 116, c).
Force in the ropes required to lift the load Q, determined by the formula
,
(34)
where η is the efficiency of one roller; η = 0.96 when installed on sleeve bearings; η = 0.98 when installed on rolling bearings; m is the frequency of the chain hoist. º
For a rope wound on a winch drum when lifting a load to a height, h is equal to l = mh.
Packing of blocks of chain hoists must be carried out with a minimum initial distance between the blocks, followed by their stretching (for example, with a tractor). When packing, the direction of bending of the rope, obtained by it during coiling into a coil, should be maintained.
The fixed end of the rope from the plane of the roller should not exceed 6º, and the distance from the winch drum to the deflection roller should not be less than 20 drum diameters.
In the absence of blocks of the required carrying capacity, free pulley blocks are used, which can operate with a drive from one (Fig. 116, d) or from two (Fig. 116, e) winches. A double chain hoist with one winch is calculated as two independently operating chain hoists. The force in the winch rope is determined from the condition of half the weight of the load being lifted.
Hand hoists, crampons, electric hoists (telphers), winches and jacks are widely used as lifting mechanisms in assembly work.
The hand hoist is a worm or gear hoist, including a chain hoist with a hand drive from an endless chain or a lever ratchet. Lifting capacity is accepted for hoists up to 3 tons.
For manual movement of goods along an I-section overhead monorail track, crampons with a carrying capacity of up to 5 tons are used.
Electric hoists (electric hoists) are designed for lifting and moving loads along a monorail track using an electric drive. The lifting capacity of the electric hoists is 0.25-5.0 tons.
Mounting winches are used with manual and electric drives. Hand-operated lever winches (fig. 118) with a lifting capacity of 1.5–3.0 tons, which are widely used for lifting and moving loads on a horizontal and inclined plane.
An electrically driven winch is divided according to its purpose into lifting, traction and rotary (for rotating assembly cranes); by the method of installation - on mobile and stationary; by the number of drums - for one, two and three reels. The drums can be smooth or grooved. Electric assembly winches are reversible. The lifting capacity of the winches is 0.5–12.5 tons, the rope capacity is 80–800 m.
An important condition for the safe operation of the winch is its reliable fastening. The winch must be secured to an anchor or some anchoring device. Anchors are called fixed anchor structures - earthen (embedded in the ground) or ground, designed to secure mounting devices - winches, pulleys, cables, cable ties, etc. Winch fastening schemes are shown in Fig. 119.
Rice. 116. Polystyrene: a - with a block for diverting a running rope branch; b - with an even number of threads; c - with odd; d - doubled with a drive from one winch; d - double, driven by two winches
When calculating the fastening of the winch, the required weight of the balancing load on the frame or the force in the anchor bolts is determined from the condition of the load stability of the winch. The coefficient of cargo stability is determined by the formula
,
(35)
where M in - restoring moment; M o - overturning moment.
Rice. 118. Manual lever winch: a - general view; b - application diagram; 1 - rope; 2 - cargo hook; 3, 5 - levers; 4 - case; 6 - hook for suspension to the support
Rice. 119. Schemes for securing winches: a - using an earth anchor; b - using a ground anchor
Rice. 119. Schemes for securing winches: c - for the column of the building; d - to the reinforced concrete or metal crossbar of the building floor; d - to a brick wall; e - a diagram for calculating the fastening of the winch
The moments M in and M o are determined from the condition that the overturning of the winch can occur around the point A of the stop of the front frame element in the anchor:
,
,
(36)
where Q is the force in the rope; G 1 - winch weight; G 2 - the force for which the anchor bolts must be calculated, or the weight of the balancing weight; a is the distance from the center of gravity of the winch to the tipping point; b is the distance from the tipping point to the anchor bolt attachment point or to the center of gravity of the balance weight; h is the distance from the rope to the tipping point.
After transformations we get
.
(37)
In addition to calculating the winch for tipping, it is necessary to calculate the winch anchor for strength and stability against horizontal displacement under the action of a shear force
,
(38)
F tr = fG 1 ,
where: F tr is the friction force of the frame on the ground; f - coefficient of friction of the frame on the ground, f = 0.3 - 0.5.
For the mechanization of installation and rigging works, hydraulic, screw, rack and pinion and wedge jacks are used.
Hydraulic jacks come with a built-in pump and are powered by a separate pump. Their carrying capacity is 200 tons or more. For the installation of equipment in the plan (for example, the frame of the balancers of the cones of the blast furnace), small-sized lightweight jacks are used. Such jacks are also convenient for aligning equipment.
Screw jacks and rack and pinion jacks are mainly used when it is necessary to move them frequently and in cramped conditions.
Wedge jacks are used mainly for aligning equipment during installation.
Rigging is the lifting of large and very heavy loads for the purpose of unloading, loading and moving. When rigging work, you need to use special mechanisms, tools and devices. Most often, rigging is used for loads that cannot be lifted and moved manually due to their heavy weight and complex configuration. Basically, such work has to be carried out in manufacturing and construction, when it is necessary to move heavy equipment. The use of rigging greatly facilitates work, and the loading process becomes clearly organized. In addition, the use of such means guarantees the safety of the equipment being moved.
Rigging mechanisms, devices and means include chains, cases, containers, traverses, slings, cables, jacks, ropes, hoist hooks, pulleys, hooks, winches, blocks and others. Here http://www.taurus-2000.com.ua/catalog/takelazh you can order rigging. If during rigging it is necessary to change the direction of the rope and reduce the force when lifting, then blocks are suitable for this. They consist of a loop, a load hook, load rods, rope rollers, and a metal clip (photo 1).
If the load needs to be lifted vertically and moved horizontally, then a winch is used. It is electric and manual. The most common today are electric winches. They have two-shoe brakes equipped with short-stroke or long-stroke magnets, gear loudspeakers and controller control (photo 2).
Rigging includes pulleys. They allow you to lift bulky loads that cannot be moved with a single block. This is a simple lifting device that consists of only 2 blocks connected by a rope. The use of a chain hoist significantly reduces the load on the winch, and also reduces the speed of moving a heavy load. The upper fixed block of the chain hoist is attached to a beam, tripod or mast, and the movable lower block is attached to the load (photo 3).
The main types of rigging are cables and chains made of stainless steel. So, stainless steel cable is used to lift, hold, and move heavy elements or loads, as well as to increase the shoulder force. Manufactured from A4 steel. Hoists are also used to move loads. It is a portable device. Sell electric and manual hoists (photo 4).
If you need to lift a large-sized load, then a jack will do it well. They are hydraulically driven, screw and rack-and-pinion. The latter have a steel or wooden case, inside which a toothed rack is placed. The screw jack has a steel body. There is a hole at the top. There are screws, trapezoidal thread, head and ratchet lever. The hydraulic jacks are powered by a hand pump (photo 5).
The elements of the rigging mechanisms are nuts. Nuts are available in any size and type. For rigging, a traverse is also used - a rigid element that is located between the load and the hook. The load is attached to the traverse (photo 6).
Slings are often used to secure the load. They help maintain the position of the load when lifting. A sling is part of a chain or rope in the form of a circle. At the ends it has special devices for hanging, strapping and securing the load. Made from different materials. Steel slings are considered strong, and for goods weighing 1.5 tons, slings made of synthetic and hemp ropes are used (photo 7).
Rigging and installation equipment
Rigging work during the installation of equipment is the most difficult and time-consuming and often reaches 50% of the total volume of work. Self-propelled boom cranes, auto and electric loaders are widely used to perform installation and rigging works. Also, auxiliary mechanisms are used, such as: mounting blocks and mounting pulley blocks, hand and electric winches, hand and electric hoists, crampons.
Blocks designed for lifting a load, changing the direction of the traction end of the rope and the device of chain hoist systems (Fig. 1.3).
Polyspast- a lifting device consisting of several groups of blocks, assembled in clips, sequentially bent around by a rope. Polyspast is designed to reduce strength S applied for lifting a load weighing G... Polyspasts have two block holders: the upper A and lower V... Clamps of blocks are equipped with a lifting shackle or hook, as well as a ring for fastening the end of the rope WITH... The multiplicity of the gain in the power of the chain hoist is approximately equal to the number of working threads of the chain hoist multiplied by the efficiency of the chain hoist (efficiency). The number of working threads can be 2, 3, 4, 5, 6, etc. With an even number of threads, the end of the rope is attached to the upper cage of blocks, and with an odd number, to the lower cage of blocks.
Pulling rope S depending on the number of working lines of the chain hoists when lifting a load with a weight G taking into account the efficiency of the pulley block:
The appearance of the cage of pulley blocks is shown in Figure 1.4.
The upper and lower blocks of the blocks can be either with a hook or with a bracket. The number of blocks in the cage depends on the number of working threads of the chain hoist.
Hand and electric winches used to create tractive effort when performing installation work outside the range of cranes. A typical appearance of the winches is shown in Fig. 1.5 and 1.6.
Cats(Figure 1.7) is used for horizontal movement of suspended loads along an I-beam or a tensioned rope.
Hand hoists(fig. 1.8) is used for lifting a load to a low height. Depending on the gear used, there are worm and gear hoists. The person lifting the load must be at the bottom. The lifting mechanism is driven by a chain.
Before working on the hoist, the hook, load chain, braking device and hoist lubrication should be carefully checked. For safe work, adhere to the following rules:
It is forbidden to lift a load exceeding the rated lifting capacity of the chain hoist;
It is forbidden to use the hoist chain for tying the load;
It is forbidden to work with a hoist with a twisted chain;
Working or moving under a raised load is strictly prohibited;
If the pull chain does not move, do not use excessive force, stop work and inspect the hoist;
It is allowed to use the hoist only for vertical lifting of the load. It is forbidden to drag the load to be lifted on the ground.
Electric hoists (telphers) with single-speed mechanisms for lifting and moving the load (Fig. 1.9) are designed to lift, lower the load and move it horizontally along a single-rail overhead track. Often they are equipped with beam cranes with a lifting capacity of up to 5 tons.
The lifting of loads, depending on the design solution, is provided by winding a cable or chain onto a drum. The control is usually carried out using the control panel, which is located below, and from it control cables go to the motors of the lifting and horizontal movement mechanism. Regardless of whether the hoist is chain or rope construction, it can be stationary or mobile. In addition, the industry produces radio control devices that electric hoist becomes an even more convenient lifting device.
Slings, grabs and traverses used for gripping and lifting loads during the installation of equipment. Rope and textile slings are more often used, less often chain ones. Textile slings have a higher breaking force-to-weight ratio than rope slings and even more so with chain slings. Textile and rope slings smooth out dynamic loads better and are more reliable.
Textile slings are safe and easy to use, they do not damage the surface of any load. Textile slings have a long service life and slow wear, since textile slings do not corrode and are irreplaceable, for example, when working in a humid environment where metal slings rust.
But there are also some disadvantages of textile slings:
They cannot be kept under ultraviolet rays for a long time and it is recommended to store them away from sunlight so that the slings retain their quality;
They are adversely affected by hot metal, fire and some other factors.
Slings are loop, circular, single and multi-branch. For hanging loads, slings can have a loop (ring) on one side and a pull hook on the other end. Figure 1.8 shows the preferred textile slings for installation work.
Grips (Figure 1.9) are the most advanced and safe lifting devices designed to reduce manual labor. Due to the wide variety of loads to be moved, there are many different gripper designs.
Traverses are removable lifting devices designed to prevent damage to the cargo during loading and unloading operations. They protect the loads being lifted from the compressive forces that occur when using slings.
By design, traverses are plane and spatial.
Plane traverses (fig. 1.10, a) used for slinging long loads. The main part of the traverse is a beam, or truss, which takes bending loads. Slings are suspended from the beam .
Spatial traverses (fig. 1.10, b) used for slinging bulk structures, machines, equipment.
Each sling, gripper, traverse must have a tag with the designation of the carrying capacity and the date of the test.
The choice of the branches of the slings is made by force
, (1.7)
where m g is the weight of the cargo, kg;
n is the number of sling branches;
α - the angle of inclination of the branches of the sling to the vertical (Figure 1.10 a).
The lifting capacity of the sling must be greater than that calculated by the formula (1.7)
When installing the equipment, they are also used jacks screw, rack and pinion and hydraulic.
Rigging works are carried out to lift various cargoes for the purpose of their further loading, unloading, transportation, movement. Rigging differs from ordinary loading and unloading operations in that they use special means and devices.
Often, such work is carried out in cases where, for some reason, it is difficult or impossible to manually load or unload items, goods, equipment. For example, when loading bulky goods, heavy loads, items of non-standard configuration.
Rigging works are mainly used in the field of moving construction materials and transporting various types of production equipment. The use of lifting equipment and devices when lifting equipment greatly facilitates the work of people. But this is not the only advantage that rigging has. Thanks to special equipment, the process of loading parts of complex equipment becomes clearly organized. In addition, it takes much less time and guarantees the safety of the equipment moved during loading and unloading.
Rigging means, devices and mechanisms include blocks, winches, pulleys, hoists, jacks, cables, carbines, ropes, chains, hooks, ropes, slings, traverses, containers, cases and others.
- Blocks are used to change the direction of the rope and reduce the force applied during lifting.
- The winch is used to lift cargo vertically and move horizontally. There are manual and electric winches.
- Polyspasts are a system of blocks and allow you to lift loads of significantly larger mass than when using one block.
- The hoists are also designed for lifting loads, are a portable device and combine chain hoists and drive mechanisms (hand hoists) or electric motors (electric hoists).
- Jacks are used to lift and move loads over short distances. Jacks are rack, screw and hydraulically driven. Ropes, carabiners, hooks, ropes are used for securing loads.
- The traverse is a rigid element between the hook and the load. The load is not attached to the hook, but to the traverse.
Some goods are transported, lifted and moved in a special container equipped with loops for slinging.
The sling for securing the load is used to maintain the position of the load in space during lifting, movement, transportation. Such devices are successfully used for transporting lumber to a homemade sawmill, in more detail. A sling is a part of a rope or chain, made in the form of a circle or with special devices at the ends for fastening, strapping or hanging a load. The lashing sling can be made of various materials.
For goods with a smooth surface and weighing less than 1.5 tons, slings made of hemp or synthetic ropes are used. These slings must not be used with metal end pieces to avoid chafing the rope.
Steel slings for securing cargo, that is, slings made of steel rope, are very strong and durable. From them you can easily determine the degree of wear. But such slings are not suitable for securing loads if the line needs to be bent or bent at an acute angle. When reused in such conditions, steel slings are bent again, the wires that make up the rope break and the slings become unusable.
Conversely, chain slings are suitable for sharp corners. In addition, unlike the two previous types, they withstand high temperatures. However, they are heavy, often do not withstand dynamic loads, and it is difficult to detect defects in them.
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