Jack – a device for lifting a variety of goods. The principal difference from the other jack lifting gear (winches, cranes and so on. D.) Is the fact that the jack is located below and not from above lifted load, eliminating the need for various support structures, chains and ropes.
Hydraulic jacks, as the name implies, run on liquid. Their operating principle is based on the movement of the piston (plunger) jack via creating a working fluid pressure (hydraulic oil) driving the pump, due to what is happening and lift the load. It lowers the load when pumping liquid from the beaker to the pump reservoir.
Hydraulic jacks feature: large load capacity combined with a small operating force due to high transmission ratio between the cross-sectional areas of the cylinder and the plunger pump; high efficiency, smoothness, rigidity and compact design. However, the initial lifting height they are much higher than the mechanical jacks. Another problem – it is impossible to accurately adjust the height lowering. In addition, these tools may occur much more serious damage than the mechanical lifting devices. Capacity of hydraulic jacks ranges from 1 to 1000 tonnes Variations referred to a variety of devices -. Is the classic bottle (odnoshtokovye and telescopic), and podkatnye, and special jacks – rombovye, duplex, and the engagement.
Hydraulic bottle type jack odnoshtokovy distinguished by simplicity of design and ease of use that extends the scope of application and can effectively perform work of any complexity. It is actively used for mounting and dismounting in any industry (engineering, construction, and so on. D.), It is suitable for the repair of vehicles, wheelsets of railway wagons, as well as the power unit presses, benders, cutters, and other similar tools. It should be remembered that it is necessary in the vertical position as possible in the other position during transportation of oil leakage to prevent leakage of hydraulic fluid from a reservoir to store and transport the bottle jack.
The design of the hydraulic jack dvuhshtokovogo (telescopic) is similar to the design odnoshtokovogo device, it features only the presence of a telescopic rod. This feature allows you to lift the load to a great height, as compared with the classic type of bottle jack.
Pneumatic jacksPneumatic jacks are used to lift (displacement) of cargo during installation, maintenance and rescue operations. They are indispensable in the case of a small gap between the support and load, with small movements, precise installation, if you have to work on loose, rough, or marshy ground. Pnevmodomkraty used for joining pipes of large diameter (up to 1200 mm), centering them in the housings and installation of supports, as well as the installation and alignment of large capacity tanks, carrying out repair and construction work on all sites.A pneumatic jack is a flat rubber-reinforced shell of a special fabric, increasing in height when applying it to the compressed air (gas). The source of compressed air (gas) can be stationary or mobile compressors and automobile compressors (pumps) or the cylinders with compressed air or inert gas.The main drawback of pneumatic jacks – their high cost. On it is influenced by the relative complexity of the design, related mainly to the sealing compounds, expensive technology of manufacturing sealed envelopes and, finally, small industrial batch release. It should also be noted that pnevmodomkrat not be used in decayed engine and it is not safe while deflating, capacity of this device is determined by the operating pressure in the actuator.