If you look to the hilt in the illustration, you can see the partition in the end of the tube. If necessary, lower the car or other cargo down the tubular valve handle is placed on the screw, and sliding is in the groove of the screw – something like a screwdriver to the contrary. Rotate the handle around its axis, the user rotates accordingly and the screw, relieving pressure in the working cylinder and lowering the load to the desired height. Most often movable jacks can be found on the tire plants – they are ideal for lifting one side of the car fast enough to work and installation. Disadvantages such design stems from the name – for movable jack requires a hard, flat surface, asphalt or concrete. Besides – a significant size and weight, to carry this unit in the car is not very convenient. So what is the place for them – and tire service stations. There is another type of movable jacks – transmission.
Pick-up of the jack is equipped with a special rotating frame. Here in all its beauty proves to accuracy and smoothness hydraulic jacks. Mounted or dismantled vehicle transmission can be accurately recorded in the vertical and horizontal planes in position. Pneumatic jack. Unlike hydraulic, pneumatic jack as a working body uses air. Structurally, this is a pneumatic pump and the same piston in a cylinder or a pneumatic cushion. In the automotive repair these jacks are used little, the nature of the working body – the air is able to shrink and make it more difficult than the liquid, keep in a closed volume.