10-06-2017, 07:14 AM
howtodesign mechanical floor jack
Abstract: - A jack is a device that uses force to lift heavy loads. The primary mechanism with which force is
applied varies, depending on the specific type of jack, but is typically a screw thread or a hydraulic cylinder.
Jacks can be categorized based on the type of force they employ: mechanical or hydraulic. Mechanical jacks,
such as car jacks and house jacks, lift heavy equipmentand are rated based on lifting capacity (for example, the
number of tons they can lift). Hydraulic jacktend to be stronger and can lift heavier loads higher, and include
bottle jacks and floor jacks. HYDRAULIC JACKSdepend on force generated by pressure. Essentially, if two
cylinders (a large and a small one) are connected and force is applied to one cylinder, equal pressure is
generated in both cylinders. However, because one cylinder has a larger area, the force the larger cylinder
produces will be higher, although the pressure in the two cylinders will remain the same. Hydraulic jacks
depend on this basic principle to lift heavy loads: they use pump plungers to move oil through two cylinders.
The plunger is first drawn back, which opens the suction valve ball within and draws oil into the pump chamber.
As the plunger is pushed forward, the oil moves through an external discharge check valve into the cylinder
chamber, and the suction valve closes, which results in pressure building within the cylinder.