The mechanical Floor Jack Low Profile uses a screw mech […]
The mechanical Floor Jack Low Profile uses a screw mechanism to apply force to the jack body and lift the vehicle. The short thread distance of the screw gives the mechanical advantages, allowing for moderate effort to increase the heavy load. The compromise is that the screws must be turned many times to achieve a small number of elevators. These are the type of jacks that you found in the vehicle roadside auxiliary toolbox.
The handle of the floor jack low profile is positioned so that the hinge gives the user a great mechanical advantage from the very beginning. For each lap force applied to the floor jack handle, a large amount of force is applied to the hydraulic piston system to exponentially. The hydraulic system consists of a reservoir, two different diameter cylinders and various flow control valves. The mechanical force from the jack handle is applied to the small hydraulic piston and is then enlarged to a greater force due to the difference in diameter of the hydraulic chamber.
Fluid Dynamics is called Fascal's law that the pressure applied anywhere in a closed incompressible fluid is uniformly delivered in all directions of the entire fluid so that the pressure change (initial difference) remains constant. Ha ha! Well, basically this means that when you push fluid from a chamber into a larger chamber, the pressure in both hydraulic chambers remains the same. However, this is an important part, in the large cylinder, the pressure distribution in the larger piston surface area, resulting in greater force.
When the floor jack low profile is in the lift mode, the valve system is considered to be closed (usually, the valve is closed by twisting the right jack handle). In this mode, the function of the jack is as follows: jack handle is raised, the liquid through a check valve (one way) into the small hydraulic cylinder, out from the tank. Jack handle is pushed down, the pressure accumulated in the small cylinder, forcing the hydraulic oil through another check valve into the large cylinder. The pressure generated in the large cylinder moves the large piston with a large force. Note that although the output is high, but the distance traveled by the large piston is much smaller than the distance of the small piston. This is because the jack handle must be raised and dropped many times to lift the jack a short distance. The piston of the large cylinder is attached to the lift arm in such a way as to provide another lever to further increase the mechanical advantages and to raise the saddle horizontally.