Using Jacks.

Use And Care Of Handtools And Measuring Tools
Page Navigation
65

(2) Ratchet Lever Jacks. A vertical ratchet lever jack (figure 48 on

the following page) has a rack bar that is raised or lowered through a

ratchet lever. Some of these jacks are equipped with a double socket; one

for lowering, one for raising.

Others have one socket as well as an

automatic lowering feature.

An outrigger ratchet jack is ratchet-operated

and has an extra reverse ratchet handle and a base plate.

(3) Vertical Hydraulic Jacks.

A hydraulic jack (figure 49 on the

following page) operates through pressure applied to one side of a hydraulic

cylinder which moves the jack head. These jacks are automatically lowered

or released by releasing the pressure. Vertical hydraulic jacks are issued

in a variety of types, in capacities from 3 to 100 tons, having different

extended heights.

(4) Push-Pull Hydraulic Jacks.

A push-pull hydraulic jack (figure

49) consists of a pump and ram connected by a hydraulic or oil hose. These

jacks are rated at 3, 7, 20, 30, and 100 ton capacities and have diversified

applications.

c. Using Jacks.

(1) Lifting Vehicles.

Vertical jacks are used to lift one side or

the end of a vehicle to permit removal of the wheel or tires, or to effect

repairs that would not be possible with the vehicle standing on its wheels.

The jack can be used on each side alternately by jacking up one side of the

vehicle, blocking it, and moving the jack to the other side, continuing this

operation until the vehicle has been raised to the desired height.

(2) Miscellaneous Lifting. The jack can also be used to raise heavy

crates, small buildings, or other items too heavy to be raised by prying

with wrecking bars. It is essential that the jack be placed on solid ground

or on a plank to spread the weight so that it will not give way or tip when

being used.