TM 9-243
TYPES AND USES - Continued
RATCHET LEVER JACKS
A vertical ratchet lever jack has a rack bar that is raised
or lowered through a ratchet lever. Some are equipped
with a double socket, one for lowering, one for raising.
Others have one socket and have an automatic lowering
feature.
An outrigger ratchet jack is ratchet operated and has an
extra reverse ratchet handle and a base plate.
HYDRAULIC JACKS
A push-pull hydraulic jack consists of a pump (1) and
ram (2) connected by a hydraulic or oil hose (3). These
jacks are rated at 3, 7, 20, 30, and 100-ton capacities
and have many different applications.
The push-pull hydraulic jacks are furnished with an
assortment of attachments that enable you to perform
countless pushing, pulling, lifting, pressing, bending,
spreading, and clamping operations. The pump is hand
operated. Simply turn the control valve (4) on the side of
the pump clockwise, stroke the hand lever (5) up and
down and the ram will extend. The flexible hydraulic or
oil hose allows you to operate the ram from a safe
distance in any desired position.
The ram retracts automatically by turning the control
valve counterclockwise. The attachments can be
threaded to the end of the plunger, to the ram body, or
into the ram base.
A hydraulic jack operates through pressure applied to
one side of a hydraulic cylinder which moves the jack
head. These jacks are automatically lowered by releas-
ing the pressure. Vertical hydraulic jacks come in a
variety of types, in capacities from 3 to 100 tons, having
different extended heights.
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