Greenlee 940-M3 Operation, Service And Parts Instruction Manual page 8

The 940 Hydraulic Pump with Control Valves
940-TA Pump
This pump is equipped with a four-way control valve,
panel-mounted, for operating double-acting rams. This
valve has two 3/8" NPT outlet ports. The lower port is
for the forward, or advance, stroke with a maximum
pressure of 10,000 psi. The upper port is for the return
stroke of the ram at a maximum pressure of 200 psi.
The control handle has three positions: Advance (turn
handle counterclockwise to extreme position), Return
(turn handle clockwise to extreme position), Neutral is
in the middle of these two positions.
This is a positive seat type valve and therefore position-
ing of the valve in the advance position must be done
firmly to make the seating effective. If stopping the ram
and holding the ram pressure during the advance
operation is required, snap the starting switch on motor
to OFF. The pressure should then be held for a sus-
tained period. (See page 9 for TA valve 501 2106.5,
Key E.)
Note: This valve is designed to return the ram piston
only when there is no load on the ram. If the
operation requires the return of the piston while
sustaining a load the TB control valve should be
used.
940-SA Pump
This pump is equipped with a control valve for operating
single-acting rams. It has one 3/8" NPT outlet port. This
model is used when the ram has spring, manual, or
gravity return. It also has a holding feature, whereby the
ram is held stationary under pressure (with motor
running) when the control handle is in Neutral position.
The control valve has three positions. Advance (turn
control handle counterclockwise to extreme position),
Neutral, or Hold, (turn control handle clockwise to
middle position), and Return (turn control handle
clockwise to extreme position). When the control handle
is in Neutral position the pump is unloaded but the ram
pressure is held. (See page 7 for SA Valve 501 5644.6,
Key D.)
Greenlee Textron / Subsidiary of Textron
940 Series Hydraulic Power Pump
940-TB Pump
This pump is equipped with a 1704 spool valve with
sub-plate panel-mounted, and is used for operating
double-acting ram.
The spool is spring-returned to Neutral from Advance
and Return positions. The sub-plate has two 3/8" NPT
ports, marked Cyl. 1 and Cyl. 2. Cylinder 1 port is the
high pressure port and should be connected to the
advance port in the ram. Cylinder 2 is the return port,
750 psi maximum, and should be connection to the
return port in the ram.
To advance the ram, push the control lever forward
(toward the valve body) to its extreme position. To
return the ram, pull the control lever away from the
valve body. Because of the balanced design of this
valve it will be noted that it operates as easily under full
load as at no load. At no time is great effort required to
move the lever.
The above 1704 spool valve and 501 2256.8 sub-plate
with relief valve are standard equipment on the 940-TB
pump. On special order the pump can be supplied
with a 501 2441.2 sub-plate without relief valve which
will deliver 10,000 psi through both cylinder ports. Also
available on special order is the 1717 4-way control
valve in which the spool is detent held in position.
(See page 7 for Valve 1704 [F] and Sub-Plate
501 2256.8[G].)
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4455 Boeing Dr., Rockford, IL 61109-2988 815/397-7070