A person is not very strong for lifting large loads, but he has come up with many mechanisms that simplify this process, and in this article we will discuss pulleys: the purpose and design of such systems, and we will also try to make the simplest version of such a device with our own hands.
A cargo pulley is a system consisting of ropes and blocks, thanks to which you can gain effective strength while losing in length. The principle is quite simple. In length we lose exactly as many times as we win in strength. Thanks to this golden rule of mechanics, large masses can be built without much effort. Which, in principle, is not so critical. Let's give an example. Now you have won 8 times in strength, and you will have to stretch a rope 8 meters long to lift the object to a height of 1 meter.
The use of such devices will cost you less than renting a crane, and besides, you can control the gain in strength yourself. The pulley has two different sides: one of them is fixed, which is mounted on a support, and the other is movable, which clings to the load itself. The gain in strength occurs thanks to the movable blocks, which are mounted on the movable side of the pulley. The fixed part serves only to change the trajectory of the rope itself.
Types of pulleys are distinguished by complexity, parity and multiplicity. In terms of complexity, there are simple and complex mechanisms, and the multiplicity means a multiplication of force, that is, if the multiplicity is 4, then theoretically you gain 4 times in strength. Also rarely, but still used, a high-speed pulley hoist; this type gives a gain in the speed of moving loads at very low speeds. low speed drive elements.
Let's first consider a simple assembly pulley. It can be obtained by adding blocks to a support and a load. To get an odd mechanism, you need to secure the end of the rope to a moving point of the load, and to get an even one, we fasten the rope to a support. When adding a block, we get +2 to strength, and a moving point gives +1, respectively. For example, to get a pulley for a winch with a multiplicity of 2, you need to secure the end of the rope to a support and use one block that is attached to the load. And we will have an even type of device.
The operating principle of a chain hoist with a multiplicity of 3 looks different. Here the end of the rope is attached to the load, and two rollers are used, one of which we attach to the support, and the other to the load. This type of mechanism gives a gain in strength of 3 times, this is an odd option. To understand what the gain in strength will be, you can use simple rule: how many ropes come from the load, such is our gain in strength. Typically, pulleys with a hook are used, on which, in fact, the load is attached; it is a mistake to think that it is just a block and a rope.
Now we will find out how a complex type chain hoist works. This name refers to a mechanism where several simple options of this cargo device, they pull each other. The gain in strength of such constructions is calculated by multiplying their multiplicities. For example, we pull one mechanism with a multiplicity of 4, and another with a multiplicity of 2, then the theoretical gain in force will be equal to 8. All of the above calculations take place only for ideal systems that have no friction force, but in practice things are different .
In each of the blocks there is a small loss in power due to friction, since it is still spent on overcoming the friction force. In order to reduce friction, it is necessary to remember: the larger the bend radius of the rope, the less frictional force will be. It is best to use rollers with a larger radius where possible. When using carabiners, you should make a block of identical options, but rollers are much more effective than carabiners, since the loss on them is 5-30%, but on carabiners it is up to 50%. It is also useful to know that the most effective block must be located closer to the load to obtain maximum effect.
How do we calculate the real gain in strength? To do this, we need to know the efficiency of the units used. Efficiency is expressed by numbers from 0 to 1, and if we use a rope large diameter or too hard, then the efficiency of the blocks will be significantly lower than indicated by the manufacturer. This means that it is necessary to take this into account and adjust the efficiency of the blocks. To calculate the actual gain in strength simple type lifting mechanism, it is necessary to calculate the load on each branch of the rope and fold them. To calculate the gain in strength of complex types, it is necessary to multiply the real forces of the simple ones of which it consists.
You should also not forget about the friction of the rope, since its branches can twist among themselves, and the rollers under heavy loads can converge and pinch the rope. To prevent this from happening, the blocks should be spaced relative to each other, for example, you can use a circuit board between them. You should also purchase only static ropes that do not stretch, since dynamic ones give a serious loss in strength. To assemble the mechanism, either a separate or a cargo rope can be used, attached to the load independently of the lifting device.
The advantage of using a separate rope is that you can quickly assemble or prepare a lifting structure in advance. You can also use its entire length, this also makes it easier to pass knots. One of the disadvantages is that there is no possibility of automatic fixation of the lifted load. The advantages of a cargo rope are that automatic fixation of the lifted object is possible, and there is no need for a separate rope. The important thing about the disadvantages is that it is difficult to pass through the knots during operation, and you also have to spend a cargo rope on the mechanism itself.
Let's talk about the reverse motion, which is inevitable, since it can occur when the rope is caught, or at the moment of removing the load, or when stopping to rest. To reverse did not arise, it is necessary to use blocks that allow the rope to pass in only one direction. At the same time, we organize the structure so that the blocking roller is attached first from the object being lifted. Thanks to this, we not only avoid backtracking, but also allow us to secure the load while unloading or simply rearranging the blocks.
If you are using a separate rope, the locking roller is attached last from the load being lifted, and the locking roller should be highly effective.
Now a little about attaching the lifting mechanism to the cargo rope. It's rare that we have a rope at hand required length to secure the moving part of the block. Here are several types of mechanism mounting. The first method is using grasping knots, which are knitted from cords with a diameter of 7-8 mm, in 3-5 turns. This method, as practice has shown, is the most effective, since a gripping knot made of 8 mm cord on a rope with a diameter of 11 mm begins to slide only under a load of 10-13 kN. At the same time, at first it does not deform the rope, but after some time, it melts the braid and sticks to it, beginning to play the role of a fuse.
Another way is to use a clamp general purpose. Time has shown that it can be used on icy and wet ropes. It begins to crawl only with a load of 6-7 kN and slightly injures the rope. Another method is to use a personal clamp, but it is not recommended, since it begins to creep with a force of 4 kN and at the same time tears the braid, or can even bite the rope. These are all industrial designs and their application, but we will try to create a homemade chain hoist.
Any industrial production to one degree or another associated with the installation of large and complex loads. In many cases, a person cannot do such work on his own. For this purpose, rigging means, mechanisms and devices are used. With their help, moving, unloading, loading objects of any configuration and weight becomes possible.
Rigging work
They represent operations related to lifting, holding and moving various objects - parts, assemblies, equipment. The key difference between these works and conventional loading and unloading is the use special devices. Often rigging equipment have a specific configuration. Their use is determined by the impossibility of moving objects due to their size and weight by other means. The timing of the work, as well as its cost, are determined by the complexity of the operations, the nature of the cargo, as well as the presence of specialized organizations in the region.
Purpose
Rigging mechanisms - devices, used for transporting large equipment. The main task of work using special equipment is not to eliminate human participation in them, but to increase the efficiency of operations. The services of riggers are used industrial enterprises. Rigging devices allow you to move machines, workbenches and other large equipment in the shortest possible time. In addition, special equipment makes it possible to increase the safety of operations and ensure the safety of cargo. Rigging devices are used not only in industry, where transportation of equipment is one of the most important parts of the work process. Special equipment is often used in the domestic sphere. For example, the services of specialized organizations are resorted to when it is necessary to transport safes, musical instruments, furniture, etc.
Rigging devices
Enterprises offering relocation services use in their work various devices. All of them are united by the term “equipment”. In practice, the following are mainly used:
- Slings.
- Blocks.
- Hooks.
- Ropes.
- Eyelets.
- Pulley hoists.
- Chains.
- Clamps.
Ropes
As a rule, steel, nylon and hemp cables are used. The latter can be tar or white. They differ in production technology. Hemp threads impregnated with resin are considered more practical. In addition, they have high strength. White ropes are more flexible. They have a smaller safety margin and are not used for mechanisms equipped with a machine drive. For installation work such ropes are rarely used. Steel cables differ in cross-sectional shape and are classified according to design characteristics. As a rule, round and flat ropes with single, double, triple lay are used.
Slings
These are represented by sections of ropes of different configurations. Slings are used to securely and quickly secure the transported cargo. They can be electronic or manual. Slings are used for direct loading/unloading. The maximum height to which the load can be lifted is 3 m. The maximum weight of objects for which slings are used is up to 10 tons. Jacks are used to lift to a small height. They can be screw, rack and pinion, wedge, hydraulic.
Pulley hoists and blocks
These mechanisms, as a rule, are part of various lifting equipment. The chain hoist is the simplest lifting device, consisting of blocks. The latter are connected by a rope. The blocks differ in the number of rollers (single and multi-roller).
Winch
Its design includes blocks or pulleys. With the help of these elements, the load is directly lifted. Winches are distinguished by type of drive. It can be electric or manual.
Support structures
Often, rigging involves hanging and holding a load on a structure that can support its weight. In this case, hoists are used. If the work is carried out indoors, they are fixed to ceilings and other building elements. If they are missing, then special equipment is installed - supporting structure. As a rule, it is a metal vertical stand, which is held in place by special guy wires. A heavy slab is provided as a support in the structure.
Safety
In production rigging work quite heavy objects are lifted and moved. Their weight can be up to several tons. Experts have developed safety rules for using rigging devices. The requirements take into account all hazards during operations. Employees of the organization providing rigging services undergo mandatory training and advanced training courses. To perform work, you must obtain a special permit and undergo a medical examination.
equipment requirements
To maintain performance, regularly carry out inspection rigging equipment, mechanisms, devices. The inspection is carried out within the established time frame. Traverses are inspected at least once every six months, containers, pliers and other grips - 1 r/month, slings - 1 r/10 days (except for those rarely used).
Extraordinary full technical certification of equipment must be carried out without fail after repair of metal elements with replacement of design parts and assemblies, reconstruction, overhaul, replacement of hook and other similar operations. The results of the procedure are recorded in the journal of rigging mechanisms and devices.
After replacing worn-out ropes, when they are reattached, the reliability of fastening and correct reeving is checked, and the cables are covered with a working load.
Technical certification and accounting of rigging equipment, mechanisms and devices carried out by an engineer and technical worker performing supervisory functions at the enterprise, with the participation of an employee responsible for the good condition of the equipment. The latter can independently check the reliability of the ropes and the correctness of the reeving, tightening with the load after repositioning or replacing the ropes. The form of the logbook for recording rigging equipment and devices corresponds to Appendix 9 to the Safety Rules when working at height (approved by Order of the Ministry of Labor No. 155n dated March 28, 2014).
Safety precautions
Rigging work involves the use of slings, with the help of which it is carried out to the lifting mechanism. Before slinging, the specialist must know the entire object. As a rule, the weight of the load is indicated on a plate attached to the frame. If the object is packed, the weight is marked on the box or lining. Lifting and moving objects is carried out in strict compliance with the following rules:
- Slinging of the cargo, which is accompanied by a passport and instructions, is carried out according to the specified technology. The slings are secured in the eyelets provided for them using special hooks on the equipment.
- Slinging should be carried out taking into account the factors of balance and stability of the load during its lifting and subsequent movement. Mechanisms and equipment mounted on the same frame are raised after securing the slings to a common platform. Sheet packaged material is moved using special lifters, which are suspended on a traverse.
- Slinging of channels, angles and other profiled metal products is carried out using universal devices. In sharp corners, pads are placed under the slings.
Classification of objects
All cargo that is transported is divided into certain groups depending on weight:
- Lightweight - up to 250 kg.
- Heavy - 250-50000 kg.
- Very heavy - more than 50 tons.
There is another category - dead weights. They are objects frozen to the ground, dug into it, fixed to a foundation, pressed against other objects. The mass of such cargo is usually unknown. The use of cranes to lift them is strictly prohibited. Objects are also classified by their size and can be oversized or oversized. In the first, the parameters do not exceed the standards defined in the traffic rules (motor transport), or correspond to the dimensions of the rolling stock (for railway transport). These indicators exceed established standards.
Conclusion
One of the key factors in ensuring safety is the high professionalism of the company’s personnel performing rigging work. The employee must have a good knowledge of the equipment he uses and the features of its operation. The work is controlled by the foreman. He is responsible for fulfilling established rules and normal. Special instructions are being developed for personnel, deviation from which is fraught with serious consequences.
Once upon a time, the working option for building my house was timber. And calculating the savings, I worked out different variants, including how to assemble a wooden house alone. Of course, this is not very convenient, but the budget was very limited. I abandoned the “kidney” technology, so I thought about a lifting device and looked for suitable solutions around and on the Internet.
One person can lift logs weighing 100-150 kg using simple tools. And if there are forest trees on the site and a crane is not suitable, it is difficult to do without such devices.
For example, this log house was assembled entirely by a man alone. At the same time, he did not move the crane, he stood in one place all the time.
Drawings of another device, light and mobile:
And here is their embodiment in matter :)
The same thing, but when, in addition to “putting it on” on the wall, there is also the opportunity to install it on a plane:
Device drawings:
An original solution made from improvised means, along which the log “rides” to the top like on a bicycle :)
Materials for the crane were mainly found in scrap metal. We only had to buy bearings, a winch, and order parts for the turning mechanism from a turner.
And I also had to pay the welder, since I myself welding work I can’t do it because of some vision problems.
In general, this crane cost 5,000 rubles, which cannot be compared with the amount of work that I managed to complete with its help, because the “cheapest” helper in our region costs 800 rubles per day.
I’ll immediately make a reservation that during operation, my faucet revealed some shortcomings, which I will point out and advise on how to correct them. So your faucet will be a little different from mine.
Let's start with the rotating mechanism
It consists of six parts that need to be ordered by a turner, and two bearings.
As you can see, there are no dimensions in the drawing. The fact is that Exact size, like mine, you don’t have to follow it at all. After all, we make the faucet from available material, and I cannot know what size channel or I-beam, or what kind of pipe you will have at hand.
A little more or a little less doesn’t matter in my design. And you will understand this from further instructions. And having generally estimated what materials and parts you have, determine what dimensions to take for the manufacture of the rotating mechanism.
The mechanism has two bearings. At the top, between the housing and the base, there is a support bearing. Below, again between the housing and the base, there is a simple radial bearing.
Or rather, the housing should be mounted on the bearing, and the base should fit into it. Thus, both of these parts are connected. For more reliable fixation of the radial bearing, a nut is screwed onto the housing from below. The thickness of the threaded and retaining parts of the nut is at your discretion, but not less than 3 mm.
Then this unit is attached to the platform with a bolt (I have an M 26), which attracts the base to the platform. Thus, it turns out that the platform and base are a stationary part of the mechanism, and the body with the nut is rotating.
Now a little about what practice has shown. Towards the end of the season, the radial bearing weakened a little, and a barely noticeable play formed in the turning mechanism.
But with a boom length of 5 meters, this play became noticeably noticeable, so I recommend installing a hub bearing, 36 mm wide, instead of a radial bearing.
Here in Kazan, support and wheel bearings can be bought for 500 rubles both. And to tighten the bolt securing the base to the platform, you will need a spanner with an extension, and definitely two washers - a flat one and a lock washer.
Our next node will be the rack.
To make it you will need a piece of pipe (I have d140) and four pieces of channel. The height of the stand needs to be estimated so that finished form she was just the thing for you. Even two centimeters lower. Then it will be convenient to turn the winch when operating the crane.
Since God is unlikely to send you a piece of pipe with an evenly cut end, you will have to cut one end yourself. To do this, we take a car clamp, or make a clamp from a strip of tin, and tighten it on the pipe.
When tightened, the clamp will try to position itself on the pipe as evenly as possible, and if you help it a little (by eye), you will get a fairly even line around the circumference of the pipe, which you just have to draw, then remove the clamp, and cut the pipe along this line using a grinder .
Then, the rotating mechanism platform is welded to this flat end of the pipe. Now it’s clear why I didn’t give the dimensions in the drawing? You still have to order the rotating mechanism. And you can find a tuba. This means the diameter of the platform can be ordered according to the diameter of the pipe.
Now the legs. They need to be welded so that the stand does not collapse. How to do it? Firstly, they need to be cut to the same length.
Then hang the pipe with the welded platform, passing the rope through the hole in the center of the platform, and place your legs diagonally towards the pipe, so that in the end, the pipe remains hanging evenly, and your legs rest against it on all four sides.
As soon as the balance is found, you need to draw by eye the corners of the channels that abut the pipe, and trim them with a grinder as shown in the photo.
After trimming the corners, lean your legs against the pipe again, catch your balance, check with a rack and tape so that they form an even cross, and secure them with welding. After tacking, check the cross again, and you can weld.
All that remains is to make the support cross itself. It can be made from any rigid profile. At first there was an idea to put it on wheels made of bearings, but time was running out, and it didn’t come to the wheels, but actually it would have been nice. The unit turned out to be quite heavy, and it was difficult to move it.
The length of the arms of the cross is 1.7 meters, although as operation has shown, this cross does not play a particularly large role in the stability of the crane. The main stability is provided by balance, which we will talk about later.
The cross is not welded to the legs, but is attached with M 10 bolts and nuts. This was done for ease of possible transportation. The legs were reinforced in anticipation of installing wheels, but they never got around to it, although the idea of installing them is still there.
The stand with the rotating mechanism is ready, now let's move on to the crane platform, on which the counterweight, winches, and boom will be installed. I found a one and a half meter I-beam, 180 mm wide, for the platform. But I think you can use a channel and even a 150 x 200 beam under it.
At first I even wanted to use timber, but since I found an I-beam, I chose it. The platform is attached to the rotary mechanism body with four bolts and M 10 nuts.
If you use timber instead of an I-beam, then you will need to make additional platforms for it, above and below. You can “encircle” it with two pieces of channel and tighten everything with bolts.
But we’ll wait with the bolts for now, since the place where the platform is attached to the rotating mechanism will need to be selected based on balance. That is, the crane boom must be balanced by a block for counterweights and a winch. That is, the crane must stand confidently on the stand and not fall over.
Next will be the counterweight block.
I have it made from pieces of the same channel as the platform, but it can be made from anything, and in any way. The main thing is to have a container in which you can install loads, so that if necessary, you can increase the counterweight.
Now about the winch. My winch is installed with a capacity of 500 kg, with a brake. And once again, as practice has shown, such power was not enough to lift a load of about 100 kg.
That is, you can lift it, but you have to lean so hard on the handle that when lifting to a height of more than 5 meters, you get tired very quickly. For such a crane you need a winch of 1 - 1.5 tons.
There was also supposed to be a second winch for lifting the boom, but it was at that time, having visited a bunch of shops and markets, that I could find only one winch with a brake, which you see in the photo. Therefore, instead of a second winch, a temporary tension cable was made, the length of which is still changed using clamps.
Unfortunately, there is nothing more permanent than a temporary structure. I still recommend that you install a winch instead, preferably a worm one. Its speed is low, and the brake, whether up or down, is dead. That's what an arrow needs.
All that remains is to make an arrow, which is what we will do. The boom consists of a mount with a shaft, a beam 150 x 50, and a tip with a pulley.
First, the mounting body. It is better to make it from a piece of channel wood.
Any round timber with a diameter of 20 to 30 mm will do for the shaft. For example, I cut off a piece of the rotor shaft of some old engine. Then we bend it in a vice, put two brackets around this shaft and fasten it to the channel, into which the beam will then be inserted.
We buy two simple bearings, so that they fit tightly onto the shaft, and cut out a seat in the mounting body.
Of course, you can dream up how to secure the bearings in the housing. Besides mine, there are probably a dozen more ways. And I found an ebonite plate, 10 mm thick, from which I made these fasteners.
The boom itself is a beam 150 x 50, 5 meters long. It is inserted into a channel 80 mm wide and 2.5 meters long. True, I had to trim it a little so that it would go inside the channel. I have a channel installed, 3.5 meters long, but this is only because I didn’t have it at hand at the time good timber, with small knots. I simply played it safe, which, unfortunately, increased the weight of the arrow.
The timber is secured to the channel with ties made from a metal strip 3 mm thick.
At the end of the boom, you need to attach a pulley for the cable. Mine is made from a wheel from a trolley bag. For skilled hands, I think there are plenty of options for attaching the pulley. At first it was fastened between two pieces of plywood, but then I made a fastening from a channel.
Now you can assemble the arrow, if not for one “but”. During operation, the brackets that secure the shaft to the channel turned out to be rather weak. So I made them stronger.
And one more addition. My reinforcing part is secured with four bolts. You need to add two more on top to make the knot more rigid. Although mine works fine with four bolts. Otherwise I would have added it long ago.
Now you can assemble the entire crane platform, that is, install a winch on it, a block for counterweights under the winch, and at the other end - a boom lifting body with a boom. If there is, then a second winch, if not, then a guy rope, like mine.
All this is assembled in a lying position, and upon completion it is raised vertically, onto some kind of support. For example, I stacked several pallets on top of each other and placed the assembled platform on them so that the counterweight hung freely downwards.
Then we fasten swivel mechanism to the counter. The most important thing remains - install the platform on the stand so that the boom and counterweight balance each other.
Unfortunately, I don’t have any photographs of the structure that I built for this, well, I’ll try to explain it this way.
This design is a tripod with a block at the top. The height of the tripod is approximately three meters. It is made from 100 x 50 timber. As you probably already guessed, the assembled crane platform needs to be suspended and raised so that a stand can be placed under it.
The platform will be raised using its own winch. To do this, we pass the winch cable through the block and hook it to the boom lifting body, which is located at the opposite end of the platform.
Now, if you operate the winch upward, the entire platform will rise. But during the rise, the arrow, raised up, begins to collapse, so you need to either call a couple of assistants who will fix the arrow in a vertical position, or make another tripod (as I did) with a block 6 meters high, and tie rope to the end of the arrow, let it through the block, and pull it up as the platform rises.
Having suspended the platform in this way and placed a stand under it, you can lower and raise the platform and move the stand to find a position in which the counterweight will balance the boom.
In this position, drill 4 through holes and bolt the platform to the rack. OK it's all over Now. The tap is ready. You can start testing.
Well, a couple of examples of operation:
General view of my faucet:
If the article does not answer your question, ask it in the comments. I will try to answer as quickly as possible.
Wish labor successes, as well as the ability to lift and move everything you need and where you need it.
During the construction process, it is very often necessary to move all kinds of cargo, building materials, parts, etc. The most labor-intensive of these movements is vertical. For example, lifting bricks, buckets of mortar, blocks scaffolding or on the ceilings of the second floor. Such movements require large physical and time expenditures.
Of course, the simplest solution is to invite a crane to the construction site. But this is expensive and does not always solve the problem. So, you can’t lift a lot of bricks onto scaffolding, they simply won’t hold up. And if you lift it little by little - taking into account the cost of the crane and the speed of laying this brick - the brick wall will simply become golden.
With this article I want to remind you only of simple and well-known techniques for a quick and, in general, not too labor-intensive way of moving building materials at a construction site.
The simplest of them is a block. Everyone knows what he looks like and I’m not even giving a photo of him, just diagrams. The meaning of the block is to change the direction of application of force. For example, for block 1 in the diagram (the simplest case, called a fixed block), in order to lift the load up, you need to pull the cable down. And this will make it possible to use the worker’s own weight to lift the load. For example, you can make several loops on the cable, then the worker steps on them as if on rope ladder can easily lift up a load of 50-70 kilograms with almost no effort!
Block 2 (in the diagram, moving block) has one end of the cable fixed motionless and already allows the force to be doubled, and a worker using such a block will already be able to lift a load of 100 kilograms. The disadvantage is that the cable also needs to be pulled up. But if you combine block 2 with block 1, the lifted load can reach double the weight of the worker, which can now be used again!
Such a combination of several blocks of type 1 and 2 is called a chain hoist. The chain hoist gives a gain in strength equal to the number of blocks. Those. to lift a load weighing 1000 kg, having a chain hoist with 6 movable and 6 fixed blocks, an effort of only 85 kg will be required!
A pulley block is a rather complex device, so a block with two pulleys is often used different diameters or a block on a thick axle that serves as a second block.
So block type 3 (in the diagram) gives a gain in strength equal to the ratio of the radii of the large and small blocks. The well-known gate in a well is constructed in approximately the same way. You remember that the log or pipe on which the chain or rope is wound is much smaller than the wheel (or the radius of the handle) with which the gate rotates. This allows even children to lift a full bucket of water from the well with ease.
Blocks and pulleys of all types are readily available. However, they have one significant drawback - they move loads only vertically. Therefore, the so-called crane - rocker arm should be recognized as a more valuable lifting and transport mechanism.
The crane represents nothing other than the famous lever of Archimedes. Although he was known much earlier than Archimedes, back in the very ancient Egypt. With the help of cranes, Egyptian workers pumped Nile water into canals and ditches.
The beauty of the crane is its simplicity, extreme cheapness and very high efficiency. I had to use it myself. It so happened that much more rubble was poured into the basement than required and it was necessary to lift the excess. How? Carrying buckets up the stairs? The work is extremely unproductive, hard and thankless. I had to urgently make a crane from discarded boards and poles. The easiest way turned out to be to hang the boom (yoke) of the crane on strong cable(for transporting the car). Now lifting a bucket of crushed stone (more than 20 kg!) took 2-3 seconds! (it took longer to load).
The crane also uses the weight of the worker himself. In addition, counterweights can be used, which also makes lifting heavy objects easier.
But the most valuable quality is that it also moves the load horizontally! Within the range of your arrow, of course. Therefore, sometimes it makes sense to use a crane not only for lifting, but also to move cargo from place to place.
The crane is also useful if you need to lift the load to a sufficiently high height. In this case, the crane's arrow is hung quite high, and so that the worker below can operate it, a strong rope or small pole is tied to the butt. A crane is installed at the end of the arrow fixed block with a long rope. This will allow 1 person to lift loads completely freely, for example, to the second floor. And this is instead of carrying them along stairs or walkways.
Such simple lifting and transport mechanisms can significantly speed up and facilitate rigging and construction works without any special additional costs to their organization. Apply them on your construction and you will feel the difference!
