Jack is an important device for lifting heavy objects f […]
Jack is an important device for lifting heavy objects from the ground, usually used to disassemble or adjust the car wheels. Almost all the drivers of heavy-duty vehicles or light vehicles carry Scissor Jack 2 Ton for the simple reason that they can only play the role of several people in an emergency situation. The screw jack is a simple machine, such as a pulley or lever, used to raise the load with a little manpower.
A simple screw jack includes a thick solid rod in which the threads have been cut, in which the rotatable substrate, and the threads pass through the blocks or nuts. The block is shaped in such a manner that it is hooked on the underside of the vehicle. The block is slowly raised or lowered when the screw is rotated by means of a Tommy bar through a screw hole.
The thread is a screw cut made on the rod so that the screw can be considered a helical tilt plane. For each complete rotation of the screw, its advance is equal to the pitch of the screws. The spacing of the screws is the distance between the adjacent ridges of any tow of the thread. The screw with a diameter of three-quarters of the screw can have six threads per inch, so the thread pitch is one-sixth the inch.
Even if the threads of the screw are kept clean and lubricated well, there is still a considerable amount of friction between the screw and the lifting block and the base plate. Thus, by one of the four wheels of an ordinary household car, the weight of 225 kg, which is weight. If there is no friction, it can boost the effort of 1.25 kg. But in fact, this effort will be between 3.4 kg and 4.5 kg. In other words, it is an ideal machine, it does not need energy to move its parts, because the speed ratio is equal to the mechanical advantages.
The screw jack is one of the kinds of manual lifting tools, its compact structure, the rational use of rocker swing, so that the pinion rotation, the operation of a pair of conical gear, driven screw rotation, pushing the lift sleeve, so heavy or decline.