Do-it-yourself mechanisms for lifting loads. Garage: homemade lifting devices

Lifting heavy loads to a height, even if not very high, is a very difficult task for a person. However, quite a lot of different mechanisms and devices have been invented to facilitate this process. The chain hoist should be included among such mechanisms without fail. In our article, we will talk in more detail about this device, and also talk about the technology for creating a chain hoist at home.

How to make lifting easier

The chain hoist is a system that consists of fixed and movable blocks connected to each other by chain or cable drives. This device was invented a long time ago, because even the ancient Greeks and Romans used similar mechanisms. Over the next millennia, the components of this apparatus and its purpose have not changed much. To date, this device is used almost in its original form, with only minor changes.

Scheme of operation of the chain hoist

Polyspasts are mainly used in boom mechanisms of building cranes. For chain hoists, despite all their diversity, there are two main requirements: an increase in speed (high-speed mechanisms are responsible for this) and an increase in strength (the so-called power chain hoists). Elevators usually use the former, while the latter have found use in cranes. It should be noted that the important fact is that the circuits of power and high-speed devices are almost completely mutually inverse.

A conventional chain hoist is a device, the main components of which are:

system of blocks with movable axes;
blocks with fixed axes;
wrapping drums;
bypass blocks.

Due to the effective interaction of blocks and ropes, it becomes possible to significantly gain in strength. In strength, we win as many times as we lose in length. This is one of the fundamental rules of mechanics, thanks to which an ordinary person can easily lift heavy masses with a minimum of physical effort.

It is much more profitable to purchase this device or make it yourself, rather than renting cranes or similar mechanisms. The peculiarity of the device is that one of the sides, which is fixed on the load, is in a movable state, while the second side, attached to the support, is static. It is the movable blocks that provide such a significant gain in strength. Static blocks are required to control the trajectory of the rope and the load itself.

There are various types of chain hoists, which differ in multiplicity, parity and complexity. The multiplicity indicator determines how many times you will gain in strength using this device. So, buying a mechanism with a multiplicity of 6, you theoretically have a gain in strength of 6 times.

Simple and complex chain hoists - we understand their design

First, let's talk about simple mechanisms. You can get such a device by adding blocks to the load and support. An even chain hoist is a device in which a rope is attached to a support. If an odd number is required, then the rope is installed on the moving point of the object being lifted. Adding a block increases the instrument's magnification by two points.

So, in order to manually make a chain hoist for a conventional winch, the multiplicity of which is 2, it is enough to use only one movable block attached to the load. The rope is attached to the support. As a result, we will have an even chain hoist with a multiplicity of 2. Complex chain hoists include several simple mechanisms. Naturally, such a device gives a significantly greater gain in strength, which can be calculated by multiplying the multiplicity of each of the chain hoists used. At the same time, one should not forget about the friction force, due to which there is a small loss in the power of the device.

There are several ways to reduce the friction force of a rope. The most effective is to use rollers with as large a radius as possible. After all, the larger the radius, the less friction force has on the rope and the lifting mechanism as a whole.

How rope affects work efficiency

You can avoid pinching and twisting the rope if you use additional devices, for example, mounting plates, which allow you to spread the rollers relative to each other. We strongly do not recommend the use of stretchable ropes in chain hoists, since, in comparison with conventional static products, they lose very seriously in efficiency. When assembling a block for lifting loads, specialists use both a load and a separate rope, which are attached to the object independently of the lifting device.

The operation of individual ropes offers some advantage. The bottom line is that a separate rope provides an opportunity to pre-assemble or pre-assemble the entire structure. In addition, the passage of knots can be greatly facilitated, since the entire length of the rope is used. The only drawback is the inability to fix the load in automatic mode. Cargo ropes, on the other hand, can boast of just such a feature, so if it becomes necessary to auto-fix the load, use the cargo rope.

The reverse is important. This effect is inevitable, since at the moment of removal, as well as when intercepting the rope or stopping for a rest, the load will certainly move in the opposite direction. The quality of the blocks used, as well as the entire device as a whole, determines how much the load will go back. You can prevent this phenomenon from occurring if you purchase special rollers that allow the rope to pass in only one direction.

Let's talk a little about how to properly attach the cargo rope to the lifting mechanism. Far from always, even the most prudent master has a rope of the required length, which is required to fasten the dynamic part of the block. Therefore, several methods of fastening the mechanism have been developed:

With gripping knots. These knots are tied in five turns from cords, the cross section of which does not exceed 8 mm. The use of such nodes is the most effective and, accordingly, common. According to experts, the knots are very strong and reliable. Only a load of more than 13 kN can lead to slipping of such a node. The important thing is that even when slipping, the knot does not deform the rope in any way, leaving it safe and sound.
The use of general purpose clamps. These devices can be used even in difficult climatic conditions, for example, on wet or icy ropes. A load of 7 kN can cause the clamp to slip, resulting in damage to the rope, although not very severe.
Personal clips. They are used only for small jobs, since a load of more than 4 kN causes the clamp to slip and subsequently break the rope.

Reservation - we study the most popular schemes

This technological operation is designed to change the distance between the blocks, as well as to change the position of these blocks. The need for reeving is due to a change in the height or speed of lifting objects by setting a specific scheme for the passage of the rope through the blocks and rollers of the mechanism.

The scheme used depends largely on the type of lifting device. Reserving for winches is carried out only for the purpose of changing the length of the boom. It is performed by changing the relative position of the guide blocks. Very often, such an operation is carried out in cargo cranes, where it is required to prevent such an effect as the curvilinearity of the movement of weights.

Stocks, depending on the schemes used, are divided into the following categories:

Single. This type has found application in shooting type cranes, where the hook must be brought on one rope rope. After that, it is required to sequentially carry out static blocks. In the final stage, the hook is wound on the drum. As practice shows, this type of reeving is the most inefficient.
Double. This type is used in cranes that are equipped with a beam and a lifting boom. In this case, it is required to install fixed blocks on the boom head, while the other end of the rope is attached to the cargo winch.
Quadruple. It is in demand among chain hoists, which are used to lift objects of huge mass. Usually, one of the reeving schemes that were described earlier is used, with the only difference being that they are used separately for each hook block.

We make a chain hoist from paper cups and gears

The devices used in construction are very complex, which is logical, because here you need to lift large loads to a sufficiently high height. Understanding their design features can be very problematic. What can not be said about home chain hoists, which are used in everyday life. They are so simple and understandable that anyone can build a chain hoist with their own hands. To do this, we need the following devices:

1. several glasses of paper;
2. scissors;
3. lace or strong thread acting as a rope;
4. plasticine;
5. plastic hangers.

First of all, you need to make a basket in which the cargo will move. For these purposes, we will use paper cups through which we thread the rope. We collect the pulley block from hangers. We fix the rope or thread on the top of the hanger, after which we wind it around the crossbar several times. The basket obtained from the glasses should be hung on the bottom hanger by the hook. In principle, this collection of pulley blocks can be considered completed. To lift loads, you just need to use the mechanism correctly. To do this, you need to pull on the free end of the thread, which will lead to the connection of the hangers. Now you can try to lift heavy objects to a height.

There is another way to make a chain hoist with your own hands, which is somewhat more complicated, but differs in greater efficiency and reliability of the design. Here we need bearings, a gear, a hook, cables with blocks, and a threaded stud. First, we fix the bearings on the stud, after which we install the gear on the end of the stud, so that it is more convenient and easier to use a home-made chain hoist. It remains only to throw the cable over the gears and fix it, while the free end will be equipped with a hook, which is necessary for lifting objects.

Finally, we recall that when working with any chain hoists bought in a store or made at home, be sure to remember safety precautions. It is necessary to carefully check the design for strength and integrity. The loads themselves should be lifted smoothly and carefully, without being located under a suspended object at this time.

On the roof or upper floors, and without special devices, this is very difficult. We will describe the process of assembling with our own hands a simple and reliable construction hoist, which alone can lift up to 300 kg.

The device, assembled according to the above scheme, is absolutely mobile and can be brought to the construction site without any problems even by a car with a top trunk.

For assembly you will need:

glued timber 60x40 mm - 10 m;
timber 40x40 - 9 m;
board 25x80 - 16 m;
rigging block with bearing - 2 pcs.;
roller on a bearing with an axis - 4 pcs.;
kapron cable - 12 m;
plywood 15 mm - less than 1 m 2.

Assembly of guides

The lift is a trolley sliding on rollers between two T-rails. To make them, you need good quality wood with a moisture content of not more than 12%: a 60x40 beam and a 25x80 board. Any curvature is undesirable, the tree should not have defects.

The bar in the guide plays the role of a spacer that sets the distance between the shelves of the brand. It should be 2-3 mm larger than the diameter of the rollers, if necessary, plan the beam along the narrow end and bring it to the desired thickness.

To assemble the guide, you need to put a beam between the boards and align them along one edge. In order for the structure to be completely monolithic, it is recommended to coat the contacting edges with PVA glue before assembly.

Fold the parts, align them under the square and fix them with clamps. Then fasten the boards and the beam with white anodized self-tapping screws 55 mm long, screw them in a checkerboard pattern with a step in each row of 30-35 cm. Both boards must be fastened with screws, so the guides will be less susceptible to warping.

If you want to make the guides longer than the available lumber, lay the beams and boards with an overlap of half the length. With proper splicing, the structure will turn out to be exceptionally strong, it remains only to bring the internal joints of the boards to zero for smooth movement of the rollers.

After assembling both guides, cover them with two layers of drying oil. Check the width of the gap under the rollers, if necessary, finish with emery cloth. At a distance of 30 mm from the end in the center of the bar in the brand, make a through hole with a diameter of 14 mm. Use it to bolt the rails to the crossbars, place wide washers under the nut and bolt head. To avoid shifting the diagonals, make a half-tree join with a hem.

Trolley design

Start by assembling the frame: insert three crossbars 75 cm long between 130 cm pieces of timber 40x40 mm. Set the middle crossbar 40-45 cm from the bottom edge. Fasten the joints with self-tapping screws, or better, assemble the frame on the spiked joints.

Attach two pieces of timber 80 cm each to the lower beam perpendicular to the frame, insert a crossbar 75 cm long between their ends and fasten the structure. To strengthen the pallet, make two inclined scarves 60 cm long from a bar or board, cut the edges at an angle of 45 °. Fasten the scarf to the pallet at a distance of 40 cm from the corner.

Cut a sheet of plywood with dimensions of 83x84 cm and drill holes 20 mm from each edge in increments of 7 cm. Through the holes made, screw the bottom of the pallet to the frame with self-tapping screws 45 mm long.

If you plan to increase the carrying capacity of your trolley, the junctions of the pallet frame and gussets must be reinforced with patch plates and corners, and the plywood at the bottom with metal brackets. Attach padlock loops with a tail length of at least 70 mm to the upper corners of the frame. Insert an M14 bolt into the holes and screw a self-locking nut onto it. Under the bolts, you need to skip a piece of cable about 2 meters long and tie it into a loop, to which a traction rope will be attached through a carabiner or thimble.

Brackets for blocks

On the upper and lower crossbars, one rigging block must be fixed between the guide posts. Fastening is possible only by means of a bolted connection with the obligatory installation of wide washers under the nuts, and preferably metal plates.

It is recommended to purchase climbing pulleys with a bearing or rigging pulleys with a groove. Most products have a solid body with tightly fitting cheeks, therefore, it is not possible to throw the cable off the pulley.

If you're trying to adapt your existing rollers, fit them with a comforter lug. Roll the steel wire 6 mm thick until a loop is formed, and then bend the edges of the structure to the required distance for fastening under the nut to the axis of the block. If you equip the pulley with a swivel, it will be more convenient to lift the load and the cable will last longer.

Rollers and their fastening

For smooth sliding of the trolley, it should be equipped with four roller wheels mounted on the sides 20-25 cm from the corners. Purchase rollers with a maintenance-free bearing and a one-sided steel axle at least 20 mm long. Instead of standard rollers, ball bearings with a closed cage and a cage width of at least 25 mm or wheels from old roller skates can be used.

The roller axis must be removed and a hole drilled under its diameter in the center of the plate 40x80 mm. After inserting the axle into the hole, install it strictly perpendicular to the plate and weld it, then make four holes in the corners for the M8 bolt.

How to upgrade the lift

A very useful addition, which significantly increases the safety of use, will be the device of landing pockets for fixing the front wheels of the trolley in a raised position. This is not only very convenient when unloading, but also makes it possible to use the lift yourself.

To arrange pockets, it is necessary to cut out a part of the rear board of the guide, on which the rollers of the trolley rest. When lifting, the wheel will slip into the formed opening and stop on a U-shaped block assembled from three bars. To prevent accidental popping of the wheel, leave a small ledge on the board. After unloading, the trolley can be easily removed from the landing pockets and lowered down, holding the cable.

To lift more at once, you can strengthen the vertical frame of the cart and install a moving block on it, but this will increase the length of the rope by 1.5 times. The traction rope, in this case, is attached to one of the corners between the guide and the connecting crossbar, is passed into the movable block on the trolley, then fits into the fixed upper and lower pulleys.

It is also possible to install the gate as on a well for convenient winding of the traction rope. It can be made from a cut of a bar 100x100 mm, brought to a hexagon by a planer. To install the gate, you will need additional L-shaped racks and replacing the bolts of the lower crossbar with studs of the appropriate length. The released bolts must be used for oblique pairing of racks with guides.

Using the gate implies increased danger, because a person is always at the lift. In order to prevent the trolley from breaking and falling, it is recommended to install the simplest jumar from climbing equipment next to the upper block.

Lifting machines are designed to help a person lift something heavy to a height. Most lifting mechanisms are based on a simple system of blocks - a chain hoist. He was already familiar to Archimedes, but now many do not know about this brilliant invention. Remembering the physics course, find out how such a mechanism works, its structure and scope. Having understood the classification, you can proceed to the calculation. To make it work - your attention to the instructions for constructing a simple model.

Block system - theory

The invention of the chain hoist gave a huge impetus to the development of civilizations. The block system helped to build huge structures, many of which have survived to this day and are bewildering to modern builders. Shipbuilding was also improved, people were able to travel great distances. It's time to figure out what it is - a chain hoist and find out where you can find application for it today.

Simplicity and efficiency of the mechanism

The structure of the lifting mechanism

The classic chain hoist is a mechanism that consists of two main elements: a pulley; flexible connection

The simplest scheme: 1 - movable block, 2 - fixed, 3 - rope

A pulley is a metal wheel that has a special groove for the cable along the outer edge. As a flexible connection, a conventional cable or rope can be used. If the load is heavy enough, synthetic fiber cables or steel ropes and even chains are used. In order for the pulley to rotate easily, without jumps and jamming, roller bearings are used. All elements that move are lubricated.

One pulley is called a block. Polyspast is a system of blocks for lifting loads. Blocks in the lifting mechanism can be fixed (rigidly fixed) and movable (when the axis changes position during operation). One part of the chain hoist is attached to a fixed support, the other to the load. The movable rollers are located on the side of the load.

Fixed block

The role of the fixed block is to change the direction of the rope movement and the action of the applied force. The role of mobile is to gain a gain in strength.

Movable block

The principle of operation - what is the secret

The principle of operation of a chain hoist is similar to a lever: the force to be applied becomes several times less, while the work is performed in the same volume. The rope plays the role of a lever. In the work of the chain hoist, the gain in strength is important, so the resulting loss in distance is not taken into account.

Depending on the design of the chain hoist, the gain in strength can be different. The simplest mechanism of two pulleys gives approximately two times the gain, three - three times, and so on. The increase in distance is calculated according to the same principle. For the operation of a simple chain hoist, a cable is needed twice as long as the lifting height, and if a complex of four blocks is used, then the length of the cable increases in direct proportion to four times.

The principle of operation of the block system

In what areas is the block system used?

Polyspast is a faithful assistant in a warehouse, in production, in the transport sector. It is used wherever you need to use force to move all kinds of goods. The system is widely used in construction.

Despite the fact that most of the hard work is done by construction equipment (crane), the chain hoist has found a place in the design of load-handling mechanisms. The block system (polyspast) is a component of such lifting mechanisms as a winch, a hoist, construction equipment (cranes of various types, a bulldozer, an excavator).

In addition to the construction industry, chain hoists are widely used in the organization of rescue operations. The principle of operation remains the same, but the design is slightly modified. Rescue equipment is made of durable rope, carabiners are used. For devices of this purpose, it is important that the entire system is quickly assembled and does not require additional mechanisms.

Polyspast as part of a crane hook

Classification of models according to different characteristics

There are many versions of one idea - a system of blocks, united by a rope. They are differentiated depending on the method of application and design features. Get to know the different types of lifts, find out what their purpose is and how the device differs.

Classification depending on the complexity of the mechanism

Depending on the complexity of the mechanism, simple ones are distinguished; complex; complex polyspasts.

An example of even models

A simple chain hoist is a system of rollers connected in series. All movable and fixed blocks, as well as the load itself, are connected by one cable. Differentiate even and odd simple chain hoists.

Even called those lifting mechanisms, whose end of the cable is attached to a fixed support - the station. All combinations in this case will be considered even. And if the end of the rope is attached directly to the load or the place where the force is applied, this construction and all derivatives from it will be called odd.

Scheme of an odd chain hoist

A complex chain hoist can be called a chain hoist system. In this case, not individual blocks are connected in series, but whole combinations that can be used on their own. Roughly speaking, in this case, one mechanism sets in motion another similar one.

Combining a two-fold and six-fold simple chain hoist gives a complex six-fold option

The complex chain hoist does not belong to either one or the other type. Its distinguishing feature is the rollers moving towards the load. The composition of the complex model can include both simple and complex chain hoists.

Classification according to the purpose of the lift

Depending on what they want to get when using the chain hoist, they are divided into:

Power;

High-speed.

A - power option, B - high-speed

The power option is used more often. As the name implies, its task is to ensure a gain in strength. Since a significant gain requires an equally significant loss in distance, a loss in speed is inevitable. For example, for a 4:1 system, when lifting a load one meter, you need to pull 4 meters of cable, which slows down the work.

The high-speed chain hoist, by its principle, is a reverse power structure. It does not give a gain in strength, its goal is speed. It is used to speed up work to the detriment of the applied effort.

Multiplicity is the main characteristic.

The main indicator that is paid attention to when organizing the lifting of goods is the multiplicity of the chain hoist. This parameter conditionally indicates how many times the mechanism allows you to win in strength. In fact, the multiplicity shows how many branches of the rope the weight of the load is distributed.

Kinematic multiplicity

The multiplicity is divided into kinematic (equal to the number of bends of the rope) and power, which is calculated taking into account the overcoming of the friction force by the cable and the non-ideal efficiency of the rollers. The reference books contain tables that display the dependence of the power multiplicity on the kinematic for different block efficiency.

As can be seen from the table, the force multiplicity differs significantly from the kinematic one. With a low efficiency of the roller (94%), the actual gain in the pulley block strength of 7: 1 will be less than the gain of a six-fold pulley block with a block efficiency of 96%.

Schemes of chain hoists of different multiplicity

How to make calculations for a chain hoist

Despite the fact that theoretically the design of the chain hoist is extremely simple, in practice it is not always clear how to lift the load using blocks. How to understand what multiplicity is needed, how to find out the efficiency of the lift and each block separately. In order to find answers to these questions, you need to perform calculations.

Single block calculation

The calculation of the chain hoist must be performed due to the fact that working conditions are far from ideal. Friction forces act on the mechanism as a result of the movement of the cable along the pulley, as a result of the rotation of the roller itself, no matter what bearings are used.

In addition, a flexible and pliable rope is rarely used on a construction site and as part of construction equipment. A steel rope or chain is much more rigid. Since additional force is required to bend such a cable when running onto a block, it must also be taken into account.

For calculation, the moment equation for the pulley about the axis is derived:

SrunR = SrunR + q SrunR + Nfr (1)

Formula 1 shows the moments of such forces:

- Srun - the force from the side of the escaping rope;

– Sraid – effort from the side of the oncoming rope;

- q Sraid - force for bending / unbending the rope, taking into account its rigidity q;

– Nf is the friction force in the block, taking into account the friction coefficient f.

To determine the moment, all forces are multiplied by the shoulder - the radius of the block R or the radius of the sleeve r.

The force of the incoming and outgoing cable arises as a result of the interaction and friction of the rope threads. Since the force for bending / unbending the cable is significantly less than the others, when calculating the impact on the axis of the block, this value is often neglected:

N = 2 Sraid×sinα (2)

In this equation:

– N – impact on the pulley axis;

- Srun - force from the side of the oncoming rope (assumed to be approximately equal to Srun;

– α is the angle of deviation from the axis.

Pulley block

Block efficiency calculation

As you know, efficiency is a coefficient of performance, that is, how effective the work was done. It is calculated as the ratio of the work performed and the work expended. In the case of a pulley block, the formula is applied:

ηb = Srun / Srun = 1/(1 + q + 2fsinα×d/D) (3)

In the equation:

– 3 ηb – block efficiency;

- d and D - respectively, the diameter of the bushing and the pulley itself;

- q - coefficient of rigidity of the flexible connection (rope); f is the coefficient of friction;

– α is the angle of deviation from the axis.

From this formula it can be seen that the efficiency is affected by the structure of the block (through the coefficient f), its size (through the ratio d / D) and the material of the rope (factor q). The maximum efficiency value can be obtained using bronze bushings and rolling bearings (up to 98%). Plain bearings will give up to 96% efficiency.

The diagram shows all the forces S on different branches of the rope

The lifting mechanism consists of several blocks. The total efficiency of the chain hoist is not equal to the arithmetic sum of all the individual components. For the calculation, a much more complex formula is used, or rather, a system of equations, where all forces are expressed through the value of the primary S0 and the efficiency of the mechanism:

– S1=ηп S0;

– S2=(ηп)2 S0; (- 4)

S3=(ηп)3 S0; ….

– Sn=(ηп)n S0.

The efficiency of the chain hoist at different multiplicity

Since the efficiency value is always less than 1, with each new block and equation in the system, the value of Sn will rapidly decrease. The total efficiency of the chain hoist will depend not only on ηb, but also on the number of these blocks - the multiplicity of the system. According to the table, you can find ηп for systems with a different number of blocks for different values of the efficiency of each.

How to make a do-it-yourself lift

In construction, during installation work, it is far from always possible to adjust the crane. Then the question arises, how to lift the load with a rope. And here a simple chain hoist finds its application. For its manufacture and full-fledged work, you need to make calculations, drawings, choose the right rope and blocks.

Different schemes of simple and complex lifts

Base preparation - diagram and drawing

Before proceeding with the construction of a chain hoist with your own hands, you need to carefully study the drawings and choose a suitable scheme for yourself. You should rely on how it will be more convenient for you to place the structure, what blocks and cable are available.

It happens that the carrying capacity of the chain hoist blocks is not enough, and there is no time and opportunity to build a complex multiple lifting mechanism. Then double chain hoists are used, which are a combination of two single ones. This device can also lift the load in such a way that it moves strictly vertically, without distortions.

Drawings of a dual model in different variations

How to choose rope and block

The most important role in building a chain hoist with your own hands is played by a rope. It is important that it does not stretch. Such ropes are called static. Stretching and deformation of the flexible connection gives a serious loss of work efficiency. For a homemade mechanism, a synthetic cable is suitable, the thickness depends on the weight of the load.

The material and quality of the blocks are indicators that will provide home-made lifting devices with an estimated load capacity. Depending on the bearings that are installed in the block, its efficiency changes and this is already taken into account in the calculations.

But how to lift the load to a height with your own hands and not drop it? To protect the load from a possible reverse motion, you can install a special locking block that allows the rope to move in only one direction - the desired direction.

Roller on which the rope moves

Step-by-step instructions for lifting a load through the block

When the rope and blocks are ready, the scheme is selected, and the calculation is made, you can start assembling. For a simple double chain hoist you will need:

- roller - 2 pcs.;

– bearings;

- bushing - 2 pcs.;

- holder for the block - 2 pcs.;

- rope; hook for cargo suspension;

- slings - if they are needed for installation.

Carabiners are used for quick connection

Step-by-step lifting of the load to a height is carried out as follows:

1. Connect the rollers, bushing and bearings. Combine it all in a cage. Get a block.

2. The rope is launched into the first block;

3. The clip with this block is rigidly attached to a fixed support (reinforced concrete beam, pole, wall, specially mounted extension, etc.);

4. Then the end of the rope is passed through the second block (movable).

5. A hook is attached to the clip.

6. The free end of the rope is fixed.

7. Sling the load to be lifted and connect it to the chain hoist.

A homemade lifting mechanism is ready to use and will provide a double gain in strength. Now, to lift the load to a height, it is enough to pull the end of the rope. By bending around both rollers, the rope will lift the load without much effort.

Is it possible to combine a chain hoist and a winch

If you attach an electric winch to the homemade mechanism that you build according to this instruction, you get a real do-it-yourself crane. Now you don’t have to strain at all to lift the load, the winch will do everything for you.

Even a hand winch will make lifting the load more comfortable - no need to wash your hands on the rope and worry about the rope slipping out of your hands. In any case, turning the winch handle is much easier.

Chain hoist for winch

In principle, even outside the construction site, the ability to build an elementary chain hoist for a winch in field conditions with a minimum of tools and materials is a very useful skill. It will be especially appreciated by motorists who were lucky enough to get stuck in a car somewhere in an impassable place. A chain hoist made in haste will significantly increase the performance of the winch.

It is difficult to overestimate the importance of the chain hoist in the development of modern construction and engineering. Everyone should understand the principle of operation and visually imagine its design. Now you are not afraid of situations when you need to lift a load, but there is no special equipment. A few pulleys, a rope and ingenuity will allow you to do without involving a crane.

Chain hoist - a system of movable and fixed blocks connected by a flexible connection (ropes, chains) used to increase the force or speed of lifting loads. A chain hoist is used in cases where it is necessary to lift or move a heavy load with minimal effort, to provide tension, etc. The simplest chain hoist consists of only one block and a rope, while it allows you to halve the pulling force required to lift the load.

Usually, power chain hoists are used in hoisting mechanisms, which allow to reduce the tension of the rope, the moment from the weight of the load on the drum and the gear ratio of the mechanism (hoists, winches). High-speed chain hoists, allowing you to get a gain in the speed of movement of the load at low speeds of the drive element. They are used much less frequently and are used in hydraulic or pneumatic lifts, loaders, telescopic crane extension mechanisms.

The main characteristic of the chain hoist is the multiplicity. This is the ratio of the number of branches of the flexible body, on which the load is suspended, to the number of branches wound on the drum (for power chain hoists), or the ratio of the speed of the leading end of the flexible body to the driven one (for high-speed chain hoists). Relatively speaking, the multiplicity is a theoretically calculated gain in strength or speed when using a chain hoist. The change in the multiplicity of the chain hoist occurs by introducing or removing additional blocks from the system, while the end of the rope, with an even multiplicity, is attached to a fixed structural element, and with an odd multiplicity, on a hook clip.

Depending on the number of rope branches attached to the drum of the hoisting mechanism, single (simple) and double chain hoists can be distinguished. In single chain hoists, when winding or winding a flexible element due to its movement along the axis of the drum, an undesirable change in the load on the drum supports is created. Also, in the absence of free blocks in the system (the rope from the hook block goes directly to the drum), the load moves not only in the vertical, but also in the horizontal plane.

To ensure a strictly vertical lifting of the load, double chain hoists are used (consisting of two single ones), in this case both ends of the rope are fixed on the drum. To ensure the normal position of the hook suspension with uneven stretching of the flexible element of both chain hoists, a balancer or leveling blocks are used. Such chain hoists are mainly used in overhead and gantry cranes, as well as in heavy tower cranes in order to be able to use two standard cargo winches instead of one large-sized large power, as well as to obtain two or three lifting speeds.

In power chain hoists with an increase in the multiplicity, it is possible to use ropes of reduced diameter, and as a result, reduce the diameter of the drum and blocks, reduce the weight and dimensions of the system as a whole. An increase in the multiplicity allows to reduce the gear ratio of the gearbox, but at the same time requires a longer rope length and rope capacity of the drum.

High-speed chain hoists differ from power ones in that in them the working force, usually developed by a hydraulic or pneumatic cylinder, is applied to a movable cage, and the load is suspended from the free end of a rope or chain. The gain in speed when using such a chain hoist is obtained as a result of an increase in the height of the load.

When using chain hoists, it should be borne in mind that the elements used in the system are not absolutely flexible bodies, but have a certain rigidity, so the oncoming branch does not immediately fall into the stream of the block, and the escaping branch does not straighten immediately. This is most noticeable when using steel ropes.

Once upon a time, a working option for building my house was a bar. And calculating the savings, I worked out various options, including how to assemble a wooden house alone. Of course, this is not very convenient, but the budget was very limited. I refused the "zakidnyak" technology, therefore, I thought about the lifting device, I was looking for suitable solutions around and on the Internet.

Lifting logs of 100-150 kg can be done by one person using simple devices. And if there are forest trees and a crane on the site, it is difficult to do without such devices.

For example, this log house was assembled by a person completely alone. At the same time, the crane did not rearrange, it stood all the time in one place.