The Pulling Jack.—The pulling jack, [Fig. 139], is used in connection with travelling cranes over wheel presses, quartering machines, planers, drill presses and lathes. Its operation is the reverse of lifting jacks.
This Jack has an improved force-pump on the outside, worked by a lever, which draws the liquid from the upper end and forces it into the space on the opposite side of the piston. The piston rod has one of the rings attached at the end.
By this operation the rings are drawn together and with them the body to be lifted or moved, for it will be understood that this style of jack works either in a horizontal or vertical position. Hooks are furnished instead of rings when desired.
The liquid is introduced into a hole in the side of cylinder, care, being observed to push the piston into the cylinder. The proportions of filling liquid are proof alcohol two parts and water three parts.
To use this jack extend it as far as it can be pulled apart, first opening the valve in the side of force-pump. Now close this valve and work the pump lever.
This jack appeals particularly to the marine engineer, to be attached to the trolley over the engine for the purpose of raising pistons, rods and lifting various parts of the machinery.
Fig. 140.
Horizontal Jack.—The accompanying engraving, Fig. 140, shows a horizontal type for pulling armatures on to shafts, putting in cranks pins, and marine work. The directions given for the care and handling of the regular hydraulic jack apply also to this as well as other devices of the same description.