24-04-2017, 11:23 AM
Mechanical Jacks
In contrast to hydraulic jacks, mechanical jacks use only physical means of lifting and lowering their loads. Using the mechanical advantage, these cats are commonly seen in the automotive industry to lift vehicles and other loads.
A common type of mechanical jack is known as a "screw". With the use of a motor, or a lever that is operated by an operator, a screw uses the shape of its threads to raise or lower the jack. Depending on the type of jack, the screw itself may raise or lower the load, or a displacement nut rises while the screw rotates in place.
These cats have many applications that include mobile platforms in stages, configuration changes in wood machinery, and adjustments of radio telescopes. Other applications also involve the use of mechanical jacks and provide some advantage over hydraulic systems.
Mechanical systems are often self-locking. This means that when the cat power is removed, the screw remains in the same position until the power is applied again. Self-locking properties make these jacks safer to use than hydraulic units, as operators do not need to worry about power loss.
The drawbacks of a mechanical system include the fact that they are not able to lift the same loads as hydraulic lifts. In addition, the levers that provide mechanical advantage for manual operations can only reach a certain length before bending and rendering useless.