Jacks are devices designed to lift loads, adjust parts to each other and carry out maintenance.
Jack-type lifting devices have a wide range of designs using various operating principles for operation.
The need to lift the load to a certain height periodically arises in specific types of industries and in the repair of mechanisms.
The most widespread use of lifting devices has received to ensure:
- lifting loads in the conditions of auto repair shops and car maintenance services;
- installation of structures according to the level during construction and repair work;
- lifting an object of large mass to a small height;
- workflow in warehouse-type organizations;
- carrying out individual car maintenance.
Jacks differ in the type of drive they use, the following types of drives are used.
- Mechanical jack – lifting the load is carried out as a result of the application of a significant force (manual, foot);
- Pneumatic jack – requires a source of compressed air to work. On the one hand, this creates inconvenience, on the other hand, it ensures that the load is lifted to a predetermined height with minimal effort;
- Hydraulic jack – lifts an object using pressure (liquid) and is characterized by low effort required to lift loads.
- Electric jack – for actuation, access to the mains is required, which limits the use on the road by the capacitive characteristics of the battery.
According to the principle of action:
Screw jacks are performed:
- with trapezoidal thread;
- lever-screw devices.
When possible to move:
Characteristics of jacks
Screw structures, are used as standard vehicle components for repair work. The device consists of several screws with trapezoidal threads that lift or lower the load, depending on the direction of rotation of the bevel gears triggered by the handle.
The mechanism is mounted in a cylindrical body and contains a folding type pickup in the design, made in the form of a rod or a support platform.
In the process of work, the pick-up is focused on the lower surface of the object being lifted. When the handle is rotated, the gears rotate, which drive the threaded screws in translational motion.
The use of trapezoidal threads on screws is explained by:
- its inherent self-braking function;
- no need to use additional fixation when lifting;
- ensuring its reliability of holding the load.
The load capacity of screw devices is in the range of 0.5-10t.
The specifics of the use of the lift is the need for careful study of the labeling of the product.
This measure is necessary to select the maximum lifting height that would allow the change of the rear and front wheels of the machine. This is necessary, based on the specifics of the rear suspension device, for some types of vehicles, which are characterized by a large value of free play.
Due to the large amount of stroke, it is not possible to raise the rear wheels even when the maximum possible lift is reached. However, these types of lifting devices are included in the complete set of all-terrain vehicles, which require lifting to a height of about 0.5 m.
Among the screw structures of jacks, vertical-type mechanisms and a diamond-shaped horizontal principle of operation stand out.
Rhombic jacks, are produced in two versions: with mechanical and hydraulic drives. They consist of four levers connected by hinges in the form of a rhombus, lifting or lowering the load occurs when the angles of the levers change.
In the design of the jack, a groove is provided on the surface of the support platform to stop the stiffening rib located on the lower surface of the body. This detail ensures the stability of the system while ensuring lifting performance.
Modern models of rhombic-type lifting devices consist of several articulated arms moving in opposite directions, driven by compression of the clamp. The design has become more widespread than the vertical type screw mechanism and is included in most cars.
The lifting force of the mechanisms provided by the design features of the bearing elements ranges from 0.7 to 2 tons, the wheel lift is 7 cm.
Lever screw jacks consist of several rods, on the lower arm there is a support plane and an emphasis for a screw with a hinged type of fastening, and on the upper arm a pickup and a power screw are mounted.
When the mechanism is rotated by the handle, the rods move along the power screw, as a result of a change in the angle between them, a change in height occurs. The model combines the features of a rhombic and lever type of lifting devices, but has a greater carrying capacity than the latter.
The mechanism allows lifting loads weighing up to 1 ton. The total lifting height reaches 40cm. when the wheel surface is separated from the ground by 10 cm.
Rack-and-screw structuresconsisting of two main elements: a large-diameter screw and a housing, are available in two versions: with one and two screws.
Mechanisms with one large-diameter screw and a lifting platform on it are driven by a handle. It drives the support nut through the rotation of several bevel gears, resulting in the movement of the carrier.
Devices with two screws are characterized by the fact that in them the fixture body acts as a support nut, and the screw part consists of two elements. The device consists of one large screw, into which another element is screwed, having a large thread in the opposite direction.
The handle acts on a ratchet mechanism that drives a large-diameter screw that exits the housing, and another element moves from the screw device, thereby changing the height of the load.
These structures are capable of providing lifting force in the range from 0.8 to 3 tons.
It is practiced to equip medium-sized machines with such lifting devices, which are widely used for the transportation of goods.
rack and pinion jacksthe principle of operation is to move the ratchet mechanism along the surface of a vertically located rail, on which notches, holes or teeth are applied.
The design provides for the movement of the pickup in the vertical direction by means of a toothed rotating gear or a rocking arm. In order to fix the load in the device, a locking stopper is provided, located on one of the gears.
- for heavy vehicles, provides lifting to a height of up to 1m;
- in regions with poor roads to retrieve vehicles stuck in the mud.
Rack lever models are distinguished by the fact that a swinging rod acts as a drive mechanism, acting on the rail and causing a change in height.
The carrying capacity of rack-type structures ranges from 0.5-2.5 to 5 tons and more.
Designs have the ability to use the mechanism to perform the functions of a hand-operated winch. For this, lugs are provided on the upper surface of the rail and the pickup.
The rack and pinion (High-Jack) jack is convenient to use, but requires a special type of recess on the car to install it. This design is close to the surface of the body, which can be dangerous in use.
A group of hydraulic type lifting devices are characterized by:
- high efficiency;
- high load capacity;
- smoothness during lifting.
Among them stand out bottle jacks, made with a single stem or telescopic type.
Single rod designs consist of a housing, which is both a container for the working fluid and performs the function of a cylinder and a piston. A lifting platform is mounted on the piston, which has the ability to change the vertical coordinate.
When the lever is actuated, fluid is forced into the cylinder. The cylinder, when the pressure rises, extends the rod, changing the height.
The design is equipped with suction and discharge valves of locking action to overcome the flow of liquid from the cylinder volume into the pump cavity. If it is necessary to lower the load, the locking needle is removed, as a result of which the liquid is pumped through the pump into the reservoir under the action of the mass.
There are models with a foot, manual or pneumatic drive of the hydraulic pump.
Since hydraulic structures provide lifting forces up to several hundred tons, they are recommended for vehicles or heavy vehicles.
Taking into account the specifics of the use of hydraulic jacks, the design of these mechanisms provides for additional security measures:
- the use of hardened steel for the manufacture of support parts with high strength to prevent breakage;
- the use of corrugation on the supporting surface to eliminate the possible sliding of goods;
- equipping the device of hydraulic lifting devices with pressure gauges to control the generated force.
Double stem bottle design telescopic type is based on the use of several rods. The mechanism of a two-rod jack contains a small piston that allows the device to be used in a horizontal and vertical position.
The hydraulic cylinder actuates the lifting arm, which lifts the object. This type of jacks is capable of providing a greater height compared to single-rod devices.
Hydraulic rolling jack works on the principle of a bottle, however, the axis of the rod is in the horizontal axis, and the piston is not connected to the pickup. The principle of operation is that the design in the form of a trolley on wheels is driven by the movement of a lever.
Pressure reduction is achieved using a tubular type handle that rotates the screw on the valve. Transmission lifting devices are distinguished by the fact that they are equipped with a swivel-type frame. The latter mechanisms are a kind of rolling devices and are used to repair the gearbox and transmission.
The mechanisms are used at tire stations and in maintenance services.
According to the load capacity parameter, there are three types of rolling jacks:
- mechanisms used for passenger cars can withstand a weight load of up to 3 tons.
- devices used in car repair shops and technical services with a load capacity of up to 4t are characterized by the fact that they have the ability to use a quick lift pedal, the purpose of which is to preliminarily lift to provide the necessary for further pickup and rise to a greater height;
- devices used for maintenance of large machines with a lifting force of up to 20 tons, equipped with a preliminary lifting pedal and a mechanism for lifting one side of the technical tool.
With a small clearance value, the use of a rolling jack with a low pickup is practiced.
Prior to the operation of the plunger mechanism of the pump, a special stand is placed under the bottom of the car, the preliminary lifting lever of the lifting heel is activated and is used to change the initial height of the object. The maximum allowable increase in lift height is 9.3cm.
Electric lifting structures are the result of synthesis in one mechanism of mechanically moving parts and electric drive from a motor with a gearbox. The lifting force of such devices is a maximum of 2t.
The power supply of the jack is carried out from the electrical network of the car, the connection to which is made through the cigarette lighter. The current consumption is 20A, with a poor-quality battery, the reliability of the device is a big question.
Pneumatic jacks are used:
- when carrying out precise installation of equipment;
- during repair and rescue work;
- in conditions of shaky soil;
- on soils of swampy and loose types;
- for alignment and subsequent sealing of pipelines with a diameter of up to 12cm.
The pneumatic jack is connected to the compressor using a special connector, after which, by pressing the lever, air is supplied to the receiver and the object begins to rise. Often, in appearance, small lifting devices of this type resemble a pillow, which, by pumping air, lifts a technical tool.
portable inflatable jack, is a rubber container with strong elastic walls, filled with air or vehicle exhaust gases. To start work and perform lifting of the load, it is required to create an air cushion by pumping air into the jack.
It can be injected using a compressor or a pump powered by a car. Despite the apparent fragility of the device, this type of lifting mechanism is capable of providing a lifting force of 3-4 tons.
Pneumatic rolling jack is a structure equipped with wheels and locking elements with a lifting height of not more than 35-40 cm. The figures given take into account the parameters of both the rolling device itself and additional elements.
It is used in specialized centers for the maintenance of technical equipment. The lifting device is connected to a high-pressure compressor, which allows you to lift the machine to a height of up to half a meter within a few seconds.
To the advantages of screw jacks with trapezoidal thread includes the possibility of providing a high value of lifting force while maintaining:
- simplicity of design,
- ease of use,
- high operational reliability,
- light weight,
- low price.
Advantages of rhombic structures screw-type jacks consists in the presence of a sufficiently long drive handle, which allows to reduce the required effort to lift the technical tool and eliminate the possibility of damage to the hands.
The advantages include low weight while ensuring a load capacity of 2 tons, sufficient stability of the lifting mechanism.
The ability to service machines with low ground clearance, the lack of exactingness to the installation site are also among the strengths of this type of mechanism.
Lever screw jacks have low cost and good lifting height, small size and light weight.
Rack-screw mechanisms have good stability indicators and the ability to provide the necessary rigidity during operation, which positively affects the reliability of this type of fixture.
Advantages of rack-type structures consist in ease of operation, the possibility of its use in horizontal and vertical directions, high lifting force (up to 20 tons), maintainability, high efficiency (85%).
Bottle type hydraulic attachments are characterized by excellent indicators of rigidity of the connection in the process of work. They are distinguished by the need to apply minimal effort for lifting and small indicators of the initial installation height.
This type is characterized by smooth running during operation and the ability to lift loads weighing up to 100 tons.
Jacks of rolling hydraulic structures characterized by good stability parameters, low initial installation height, the need for little effort to actuate. During the work provide good indicators of rigidity and reliability.
Electric jacks are characterized by ease of operation, the ability to operate from a generator or a vehicle battery, good performance when working in extreme conditions.
Characteristic features for pneumatic models are the provision during operation of the design of a low pick-up and the presence of a supporting surface of a significant size, which ensures convenience and reliability of operation.
This type is characterized by noiselessness and extremely high speed of operation, the ability to lift massive loads, unpretentiousness to the conditions of the installation site, high efficiency (85%), ease of installation.
Inconvenience when using a screw jack with a trapezoid thread is that it has a small area of the supporting surface.
The need to install it on the frame structure is also inconvenient, since this area can not only become dirty, but also rust, which is a risk factor when working with this device.
Complicate the operation of a rhombic screw-type model there may be a small margin of working stroke in the presence of a low pickup, low efficiency of the device (30-40%), low stability in connection with which additional fixation and a lifting force limited by one and a half tons are required.
For lever-screw structures of lifting type characteristic disadvantages are: poor stability and uncomfortable drive handle.
Rack screw jacks have a large mass and increased lift height, which limits the versatility of their use. Separately, mechanisms with one screw are characterized by small lift values.
To the shortcomings of rack-type devices may be attributed to excessive weight and dimensions, there is a possibility of overturning as a result of strong gusts of wind.
Disadvantages of bottle type hydraulic devices – significant weight, high price and complex design. This type is characterized by a large value of the initial lifting height, low speed, frequent maintenance. Strict regulation of the position of the jack during transportation can create inconvenience.
A separate disadvantage of single-rod models is the small stroke of the rod.
Disadvantages of rolling type lifting devices are limitations in use due to their inherent significant weight and large dimensions.
Problems associated with the operation of the lifting device on the electric drive associated with limited energy resources, on tourist routes or travel.
For pneumatic type structures the following disadvantages are characteristic:
- high price,
- device complexity,
- inability to work with the engine off,
- the need for a source of compressed air or vehicle exhaust gas,
- accumulation in the chamber of sediment when using exhaust gas.
How to choose a jack
Conventionally, the technical parameters of lifting devices can be divided into critical and secondary, although when making a choice, the boundary between groups in the classification is blurred.
The critical indicators that determine the operation of the lifting device include the following nuances.
The lifting force of the device is one of the most important indicators, important both from the point of view of the possibility of lifting a particular technical device, and from the point of view of the reliability of the system. Reliability, in turn, is inextricably linked with the design features of devices.
The required lifting capacity of the jack is calculated by adding the weight of the used vehicle with 200-300kg, which are provided to ensure reliability when using this lifting mechanism.
The vertical movement parameter provided by the design is one of the critical parameters for hoisting machines. It is important to ensure that the installation height is sufficient for the required amount of work. However, when choosing a lifting mechanism, it is necessary to take into account the amount of free play of the damping system and ease of operation.
Based on this, it is recommended to give preference to devices with a small power reserve in installation height.
If it is necessary to provide a larger value of this value, it is recommended to use additional elements in the form of linings, stands. Sometimes a rack jack is used for these purposes, which has several times the height of the lift.
The minimum height of the beginning of the lifting of the vehicle (pickup), is limited by the overall parameters of the machine design.
The pickup provides for the free placement of the lifting mechanism under the bottom or body of the serviced vehicle.
The same indicator partially includes the convenience of access to the handle to start the mechanism and manipulate it. When choosing a jack, you need to know the ground clearance of the car and compare it with the pickup height parameters of the proposed models.
When choosing a jack, it is also important to take into account secondary technical parameters that do not directly affect the operation of the device, but are important from the point of view of design convenience during operation and maintenance.
These characteristics include:
- Overall dimensions of the product, which should ensure the possibility of using it in a set with a technical tool. On the other hand, they should be compact enough to be conveniently located in the trunk or passenger compartment with a minimum amount of space they occupy.
- The weight of the device is important from the point of view of the strength of the parts of the supporting structures, which must be made of high-quality material with a significant mass. On the other hand, the weight of the device is important in the conditions of using the limited load capacity of the machine itself.
In this case, this device parameter should tend to the minimum possible values.
- The quality of the product, which can have a direct impact on the values of the basic characteristics of the jack in case of poor-quality manufacture.
In the process of choosing a device, it is important to pay attention and check:
- smooth running of the parts of the mechanism in a given range of values;
- the presence or absence of a power reserve in the mechanism or free gaps;
- stability characteristics in the folded and deployed state;
- the presence or absence of sources of gas or liquid leakage in pneumatic and hydraulic jacks;
- reliability of fastenings of parts and components of the mechanism.
Which is better
In practice, a rhombic-type jack with a lifting force of 1.5-2 tons is enough to complete passenger cars.
To service technical equipment of a larger mass, it is better to use hydraulic and pneumatic devices of rolling types with a lifting weight of up to 8 tons.
To perform most of the technical maintenance work, a sufficient value for the vertical movement parameter is 30-50cm.
In the case of using vehicles with a ground clearance of 15 cm, for the full maintenance of the machine, rolling-type structures or screw models with a pick-up height of 6-9 cm can be used.
How to use
Lifting precautions include:
- Ensuring the operation of the device when installed on a solid horizontal surface.
- The implementation of the lifting of the technical means exclusively in the neutral position of the gear lever.
- Ensuring smooth lifting with the help of uniform and uniformly accelerated movements in the case of using a mechanical drive of the jack.
- It is necessary after completing the lift to test the stability by gently rocking the machine in various directions, which ensures that it does not accidentally fall when gusts of strong winds are strong.
- In the case of lifting both wheels, for example the front ones, it is necessary to block the movement of the rear ones, and vice versa.
- It is recommended to use additional fixing structures, such as stops, stands, bars, etc.
Depending on the manufacturer and its marketing policy, guarantees for jacks of various designs are provided for a period of 6 to 24 months.
The warranty is provided if during this period there is a malfunction of the product or a change in its performance that has a significant impact on the operation of the product.
When these conditions occur, the manufacturer, depending on the conditions specified in the warranty card, may replace the defective device or pay monetary compensation.
As a rule, the conditions under which the manufacturer’s liability arises include:
- Defects that arose during the manufacture of the product, associated with the materials used or the technology used.
- Defects resulting from improper transportation or storage of goods until the moment of sale.
To select a lifting device, it is important to first familiarize yourself with the most successful manufacturers of this type of product from the samples on the market.
Firm AE&T (Automotive Equipment & Tools – equipment and tools for car service) specializes in the production of lifting, tire fitting, press equipment. With a reasonable ratio of price and product quality, the company has a wide network of dealerships.
Manufacturer of car accessories AIRLINE specializes in the production of jacks, tools for maintenance of technical equipment, compressors and other devices.
From the point of view of marketing and product promotion, the company concentrated most of its efforts on organizing online stores, being less represented in the real market.
Firm Autoprofi specializes in the production of car accessories such as seat covers and floor mats, car chemicals, car noise insulation, batteries, rims, windshield wipers and compressors. The company is dynamically advancing in the service market, providing high quality goods, implementing a system of discounts and expanding its coverage to the global network.
Company FIT has a wide range of specialization in the range from the production of building materials to tools for garden, construction, transport, pneumatic types (welding machines, drills, spray guns, lawn mowers, etc.). The dynamic development of the company is explained by the quality of its products and a well-thought-out marketing strategy.
Firm Forsage is engaged in the production of various accessories for cars. The company has a worldwide reputation and has its own market share in many countries, thanks to the quality and reliability of their products.
Firm specialization Kraft is a manufacturer of components for braking systems, engines, alloy wheels, suspension and steering of machines. The products of this manufacturer are in demand due to their reasonable price, but because of this, they become the object of a large number of fakes.
Manufacturer Matrix specializes in the production of tools for car maintenance. The company’s products have received a fairly wide distribution and recognition of consumers, due to the good quality of the material used and the high precision of the tool.
Firm STAYER produces a wide range of tools for automotive, carpentry, repair work and is characterized by a good quality of services, thanks to which it not only occupies its niche in the market, but also gradually expands its boundaries.
The field of activity of the company STELS is the production and sale of equipment for lifting goods and equipment for warehouse equipment.
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