ADJUSTING VALVE STEM CLEARANCE

TM 94940-539-14&P

of the fluid pressure being applied against the balls which creates sufficient pressure to seal the seat.

Bearing this in mind, it will be noted that in order to open the valve it is necessary to push the ball away from the valve

seat. This is accomplished by using a left hand thread on the valve stem and bushing. By turning the valve handle to the

left (Normal valve opening practice) the tip of the valve stem contacts the ball and pushes it off the seat, resulting in an

open valve. By turning the valve handle to the right, the valve stems move away from the ball, allowing the spring to push

the ball against the seat, resulting in a closed valve.

ADJUSTING VALVE STEM CLEARANCE

Each valve knob is equipped with a stop pin located on its back side, which contacts a stationary mating pin in the

pump base after one revolution. This limits the valve opening to one turn, which is desirable. However, the valve must be

adjusted to insure proper closing and opening. To adjust proceed as follows:

Loosen the socket head screw holding the valve knob and valve stem together, then remove the knob. Using a

screwdriver, turn the valve stem left-handed, until it just touches the valve ball. The spring which keeps the valve against

its seat will offer resistance. Now turn the valve stem, right-handed, one fourth turn. Next, install the valve knob so that

the stop pins are engaged and the valve is at the RAM DOWN position. At this position, lock the valve knob and valve

stem together.

When properly adjusted, the valve knob will turn I/4 turn to the left before pushing the ball off its seat. This represents

3/4

about 0.016' clearance between the end of the valve stem and the valve seat ball. The remaining revolution of the knob,

before striking the stop pins, will open the valve fully.

K. PRESS CYLINDER

The cylinder is of the single acting type, using a leather cup to seal the fluid which extends the ram. Retraction of the

ram is accomplished by springs, when the cylinder fluid is allowed to escape to reservoir.

The ram bushing is equipped with "O" rings which serve as static seals to hold a small amount of oil in the lower end of

the cylinder which is intended as a lubricant to the ram.

Also there is incorporated in the ram assembly a travel limit valve intended to stop the ram travel at a predetermined

point to protect the cylinder assembly. This is accomplished in the following manner (see detail of cylinder assembly

parts):

A pin in a hole drilled at right angle to the ram contacts the cylinder bushing at the end of the normal ram travel (7'

or 14'). This in turn lifts a push rod which raises a ball off its seat, allowing fluid to escape from the upper end of the

cylinder into the lower cylinder area, then to the pump reservoir by way of a drain hose.

L. MOVABLE CYLINDER

The press cylinder can be moved and locked to the extreme sides of the frame. This feature permits a variety of

accommodations such as being able to work on the end of some long parts. Also, temporarily idle fixtures can be left on

one side of the press while working on the other side.

To move cylinder, turn cam locks l/4 turn to release the clamping action furnished by the cylinder retracting springs.

Adjustable push rods are used to facilitate this clamping and releasing feature.