Principle of operation
Lifting mechanisms are widely used in production, construction, service enterprises. The most common of these are hoists and winches.
Having a similar principle of operation, these devices differ in the direction of movement of the load. Tali are designed to lift and hold loads. The purpose of the winches is to move in the vertical and horizontal direction.
The action of these mechanisms is based on the transformation of the rotational movement of the drum, on which the cable or chain is wound, into the translational movement of the load attached to this cable or chain.
The variety of types of winches and hoists is based on different types of drives and gearboxes that transform their movement. Structurally, these products consist of a body or frame, a drum for winding a chain or cable, a gearbox, a brake and a drive device.
Types of winches
According to the type of drive, mechanisms are distinguished with manual or electric drive. In the first case, the muscular strength of a person is used to move the load, in the second case, the rotational energy of the electric motor.
Manual mechanisms are divided into:
In devices with a worm drive, the rotation of the drum is carried out using the «endless screw» of Archimedes. For mechanisms with a worm gear, a large gear ratio is characteristic.
Drum mechanisms transmit the rotation of the handle to the drum through a gearbox of several gears.
Such mechanisms are distinguished by simplicity of design and high reliability.
The chain drive converts the movement of the chain thrown over the drive wheel into rotational movement of the shaft. These hoists are highly efficient and allow the hoist to be hung from a beam, driving the chain from floor level.
In lever devices, the drum is driven by the translational movement of the lever and a ratchet mechanism (ratchet). Lever devices have a minimum weight and dimensions.
When using an electric drive, the rotation of the drum is performed by an electric motor through a gearbox. The composition of such units additionally includes switching equipment for controlling and protecting the electric motor, limit switches and a push-button control post.
The electric motor can be either 220V or three-phase 380V.
Depending on the traction element, winches and hoists are divided into:
Less commonly, a textile tape is used as a traction element.
Specifications of winches
- Traction force on the cargo drum. Characterizes the load capacity of the mechanism, usually 200-25000kgf;
- Rope capacity of the drum. It ranges from 10 to 630 running meters;
- Rope winding speed. It is in the range of 0.03-2m/s. For units with a large rope capacity, 2 values \u200b\u200bare indicated — on the first and last turns;
- Number of speeds;
- Rope diameter. Usually ranges from 6 to 40 mm;
- Unit weight. Depending on the carrying capacity, it ranges from several kilograms to tons;
- Dimensions. Determined by load capacity and design;
- Execution. Versions are available for indoor and outdoor use, explosion-proof design, etc.
- The force on the handle or lever at rated load. This value is tens of Newtons (only for lever or drum devices);
- Type of electrical network, power consumption of the electric motor.
Depending on the load capacity, electric motors with a power of hundreds of watts to tens of kilowatts are used (only for units with an electric drive).
For hoists, the characteristics are also indicated:
- lift height. It ranges from units to tens of meters;
- Traction and load chain parameters. The diameter and size of the chain link is determined primarily by the load capacity of the fixture.
Functionally, both devices are designed to move goods. However, there is some specification.
Waists are mainly designed to lift and hold objects. They can also be used for horizontal movement. In this case, the hoist is attached to a special carriage moving along an I-beam.
In this design, the lifting mechanism is called a hoist. The trolley drive in this case can be mechanical or electric.
Winches are used to move loads in any direction. Functionally, the following groups are distinguished:
- Traction. Designed for lifting or moving loads;
- Shunting. They are used when it is necessary to move freight cars at railroad warehouses;
- Auxiliary and drilling. Specialized units for lifting equipment to drilling sites from receiving bridges, working with casing pipes;
- Scraper. They are used to move parts of rocks during mining.
In the minimum version, the winch package includes packaging, a passport and, of course, the mechanism itself. Moreover, in some cases, the kit does not include a traction element — a cable or a chain, they are purchased separately, taking into account the required length and section.
Separate models are additionally equipped with clamps or brackets for mounting to a surface or a metal beam. Fasteners are available for I-beams and round pipes.
Winches and hoists are offered by manufacturers in a complete set sufficient for work, but additional accessories are used to expand the functionality.
- cables and chains — replacement of failed ones (cable break), and to increase the working stroke;
- hooks and slings, used to lift massive and dimensional objects, cargo of complex shape;
- magnetic grippers designed for fixing loads made of ferromagnetic materials;
- grips — used to hang the device to pipes and I-beams;
- blocks are used to increase the load capacity of the device;
- movable carriages and carriages with an electric drive are used for suspension of a hoist to I-beams for horizontal movement of goods.
Each lifting mechanism is designed for its purpose and scope. At the same time, solutions aimed at solving problems in this area are laid down in the design. However, devices of different types have characteristic features.
First of all, the scope and efficiency of application is determined by the type of drive.
Devices with a mechanical drive do not require electricity and are used in the field, they do not have an electrical part, their design is simpler and, therefore, has a lower price.
The advantage of an electric drive lies in its high efficiency. If frequent use is required, moving massive objects over long distances without an electric drive is not advisable.
Modern winches and hoists are reliable, however, in the process of working with them, there are some disadvantages that complicate operation:
- the use of gearboxes with a worm gear sometimes leads to jamming caused by the relative sliding of the worm turns and the teeth of the mating gear;
- low quality of the metal leads to bending and deformation of parts, especially at maximum loads;
- insufficient quality of welds at maximum loads causes their divergence, and the failure of the winch;
- some manufacturers do not have a lifting rope in the package, it is purchased separately;
- insufficient lever length for lever-type devices, significant effort is required to lift the load;
- devices with an electric drive have insufficient cable length to the control panel, the installation height of the drive must correspond to the cable length;
- low-power winches with an electric drive for connection to a 220V network are equipped with a short cord that needs to be lengthened;
- electric drives tend to overheat during active use, this is especially evident at maximum loads;
- when purchasing a lifting mechanism, the maximum load capacity and the length of the cable are incorrectly estimated, lay a certain margin of load capacity.
How to choose a winch
When choosing a lifting device, first of all, pay attention to the parameters of the load and the height (distance) of the lift. At the same time, a certain margin of carrying capacity of the winch or hoist is provided.
The load capacity margin is 15-30% of the nominal value.
It is also required to take into account that when using a winch, for lifting loads, the value of the load capacity is 2 times less than the pulling force.
The length of the traction element is selected in accordance with the required lifting or moving height. The stock of cable or chain on the drum should be 5-10 turns. A larger supply of the traction element leads to an increase in the mass of the unit and the cost.
Decide on the frequency of use, and the required speed of work. In the case of frequent use of the winch, an electric drive cannot be dispensed with; if it is supposed to lift loads from time to time, limit yourself to a manual drive.
In addition to energy independence, a manual winch is more reliable in operation and much cheaper.
When using an electric drive, it is required to check the compliance of the electrical network with the power consumption and the number of phases of the electric drive, or take care to purchase an autonomous generator of the appropriate power.
In the case of choosing a device with a manual drive, it must be taken into account that the worm gearbox is slower than the gear one. The installation height is also taken into account — only chain-driven devices can be suspended at a height, gear and lever devices require direct force on the lever or handle.
When choosing between a cable and a chain, the lifting height is taken into account; chains are used when lifting loads to a height of 3-5 meters.
An important factor when choosing is the weight and dimensions of the device.
Especially pay attention to the weight of the mechanism if it is intended to be used non-stationary or at height.
Overall (installation) dimensions must be checked if it is necessary to fasten the winch to the supporting surface.
Considering the design of the lifting device, pay attention to the following points:
- diameter of the drum, it should not be too small to prevent damage and breaks in the rope;
- the reliability of fastening the cable to the drum, the cable must be securely held in the unwound state;
- body material, drum, fastening parts, brake parts must be of high quality, their breakage and deformation lead to the failure of the load;
- quality of welds, unevenness and other welding defects are not allowed;
- threaded connections must be fully tightened using lock washers and nuts to prevent unraveling;
When choosing an electric drive, pay attention to the control panel — an emergency stop button is required, it is desirable that the buttons be covered with a silicone cover to protect against dust and moisture.
Which lifting device is better
It is impossible to determine the best device, the best lifting device is the one corresponding to the task being solved with the best price-quality ratio.
The load capacity of the mechanism is selected from the condition of operation with a load of 70-85% of the nominal, which corresponds to the optimal ratio of cost to load capacity. For an actively used mechanism, the use of an electrically driven device would be the best solution.
In terms of product durability, purchasing products from European brands or reputable Russian manufacturers will be the right choice.
Instructions for the operation of lifting mechanisms are given by the manufacturer in the passport or instruction manual for each specific product.
General maintenance instructions include periodic inspection and tightening of threaded connections, lubrication of friction components and parts, inspection of cables and rigging.
When operating lifting devices, it is necessary to observe certain safety measures:
- observe the general safety regulations when working with lifting mechanisms;
- before use, inspect and check all components of the unit, special attention to the cable or chain;
- for stationary winches or hoists, the fastening elements are checked;
- it is impossible to allow overloads exceeding the nominal (passport) values;
- it is strictly forbidden to use winches and hoists with a faulty brake;
- do not unwind the rope to the last turn;
- when using an electric drive, the electric motor is connected only to the electrical network corresponding to the passport data; the electric drive must not be connected bypassing the standard protection circuits.
When operating lifting mechanisms, special attention is paid to the correct slinging of the load. The material, quantity and slinging points are determined based on the shape and weight of the load.
Each manufacturer indicates the terms of the warranty in the passport for the product. The warranty does not apply to consumables and products with mechanical damage. The warranty period for lifting mechanisms is from 12 months.
Winches are very reliable devices, but malfunctions occur during operation:
- traction element damage – a damaged cable or chain must be replaced;
- gear jamming — shift of the shafts due to the loosening of bolted connections, bolted connections must be tightened and locked;
- increase in the required force on the lever or handle — check the condition of the lubricant and, in its absence, lubricate the parts;
- loud noise in the gearbox — check the condition of the lubricant, wash and lubricate the gearbox.
Malfunctions when using an electrically driven device:
- electric motor does not starta possible reason — the circuit breaker in the protection circuit has tripped, low voltage in the network or the contactor coil is faulty;
- when the remote control is off, the electric motor continues to work — sticking of the magnetic system of the contactor, sticking of the limit switches;
- undervoltage — check the cross section of the supply cable, the voltage on the input shield;
- current or thermal protection trips — first exclude the possibility of overloading the drive, check the elements of the electrical circuit for burning.
- motor hums but does not rotate under load — the motor runs on two phases (if three-phase), in the event of a hum from a single-phase motor (applies to three-phase motors as well) — it is possible that the bearing is worn, as a result, under load, locking (jamming) occurs;
- very hot brake pads — check the uniformity of the fit of the pads, the clamp and, if necessary, adjust;
- spontaneous lowering of the load — a malfunction is caused by weak clamping of the brake pads or their oiling. The surface of the pads is washed and the clamping is adjusted;
- electromagnetic brake noise caused by a gap between the armature and the core of the electromagnet, eliminated by adjusting the gap;
Minor repairs and maintenance are carried out directly during the operation of the winch or hoist. In case of a serious malfunction requiring disassembly of the gearbox, brake mechanism or electric drive, it is better to contact a specialized organization.
Repair of the electrical part of the device is carried out only by a specialist with the appropriate electrical safety approval group.
The replacement of loaded parts must be carried out only with parts supplied by the manufacturer of the device.
At the moment, many Western and CIS manufacturers represent their products on the market. The range and features of the products of some of them are presented below.
DENZEL is a German brand of hand and power tools. Lifting equipment of this brand is represented by cable hoists with an electric drive with a lifting capacity of up to 1 t and a lifting height of up to 12 m.
The kit includes fasteners for fixing on the pipe. For horizontal movement, a carriage with an electric drive is offered for installation on an I-beam.
Einhell is a German tool manufacturer. The company produces cable hoists with an electric drive with a nominal value of up to 1000 kg and a cable length of 11.5 m.
The complete set includes fastenings for installation on steel beams. The control panel is protected by a silicone casing that prevents the ingress of dust and moisture.
Fit is a manufacturer of electric, pneumatic and hand tools. Lifting equipment of this brand is represented by:
- manual lever winches with a lifting capacity of up to 4t and a cable up to 3m;
- drum winch with manual drive with a lifting capacity of 1 t and a cable of 9.5 m
Hand winches are offered in a reinforced version — with two symmetrical gears. For greater convenience and safety, the stopper is placed closer to the lever.
Jet is an international concern producing machine tools, hand tools, lifting equipment. The range of lifting equipment includes:
- manual cable hoists with a lifting capacity of up to 10 tons and a lifting height of up to 12 m;
- manual lever hoists with a lifting capacity of up to 3 tons and a lifting height of up to 12 m;
- electric hoists with a load capacity of up to 400/800 kg and a lifting height of up to 18/9 m;
- lever winches with a lifting capacity of up to 3 tons;
- electric winch with a lifting capacity of 250 kg and a lifting height of up to 60 m;
- tourist winch with electric drive with a pulling force of 450 kg and a rope up to 4.5 m
Some winches do not include a rope, sold separately. Lever winches have a telescopic arm design with a shear pin that acts as an overload protector.
The company offers additional equipment: electric carriages for electric hoists, movable carriages, clamps for fixing the hoist on an I-beam.
Kraftool is a German brand of professional hand and construction tools. The company produces manual chain hoists. The range includes mechanisms with a nominal value from 1 to 5 tons and a lifting height of up to 5 m.
Hoists of this company are made of high quality carbon steel, lifting parts of tool alloy steel. Products of this company are distinguished by compact dimensions and low weight. The locking mechanism with self-return ensures high reliability of operation.
Prorab is a Russian brand representing electrical and construction tools. The company offers under its own brand hoists with electric drive up to 1t, lifting height up to 6m and speed 4m/min.
Sorokin is a Russian tool manufacturer specializing in car service equipment. The company mass-produces several types of lifting equipment, covering the entire range of lifting capacities.
The range includes manual winches:
- drum up to 1.3t and cable length up to 15m.
- lever up to 3t and cable length up to 1m.
- traction up to 5.4t and cable length up to 20m.
The trademark also presents a line of hoists and hoists:
- lever hoists up to 9t and up to 1.5m high;
- chain hoists up to 20t and up to 3m high;
- mobile chain hoists up to 10t and up to 3m high (the chain hoist is combined with a carriage for installation on an I-beam);
- hoists with electric drive up to 5t and lifting height up to 15m.
In addition, automobile winches are produced for:
- for SUVs with a carrying capacity of up to 7.7 tons;
- for installation on ATVs with a carrying capacity of up to 2 tons;
- hydraulic electric winches for tow trucks with a lifting capacity of up to 9 tons.
Products of this manufacturer are made of high quality materials, which ensures reliability and durability. The design allows you to replace regular cables or chains with traction elements of increased length.
Some models use a textile tape as a traction element. In addition to the main units, the line includes additional accessories: consoles, blocks, slings, ropes and chains.
ZUBR is another Russian brand. In the segment of lifting devices, the range is quite wide. A stationary winch with a manual drive up to 900 kg, lever automobile winches with a lifting capacity of 2 and 4 tons are serially produced.
Among the hoists are available mechanisms with a chain drive up to 5t and a lifting height of up to 12m and with a lever drive up to 5t and a lifting height of up to 1.5m. Lifting mechanisms of this company are simple in design and reliable in operation.
The key to their durability is the quality of the materials used — all parts are made of high quality carbon steel, and the chains are made of hardened tool steel. The gear ratio is optimally matched, which ensures efficient operation with little effort on the traction chain.
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