J&M 220 Operating And Maintenance Manual - page 57

MODEL 220 

HYDRAULIC 

IMPACT HAMMER 

VI. ELECTRICAL 

CIRCUITRY 

B.  STROKE RANGE SELECT 

With the diesel engine running and the MAIN POWER switch ON, turning the 

Clamp switch (OPEN-CLOSE) to OPEN energizes the open-clamp solenoid (OPEN 

SOL).  This extends the variable stroke cylinder, fully extending this cylinder puts 

the hammer in minimum stroke mode.  Release the switch to the neutral position, 

for regular operation.  This is the recommended starting position. 

With the diesel engine running and the MAIN POWER switch ON, turning the 

Clamp switch (OPEN-CLOSE) to CLOSE energizes the close-clamp solenoid 

(CLOSE SOL) on the clamp valve (V1).  This retracts the variable stroke cylinder, 

fully retracting this cylinder puts the hammer in full stroke mode.  Returning the 

switch to the neutral position.  De-energizes the close clamp solenoid and holds the 

stroke control cylinder at the desired position. 

Adjusting the position of the variable stroke cylinder to where the stroke length most 

adequately suits the job conditions.  This can be done at any time as described 

above. 

NOTE: The pressure switch (PS1) shown in the stroke control portion of the 

electrical schematic is not used in the operation of the Model 220 hydraulic 

impact hammer.  The adjustment of this switch should remain at the setting 

required for a Vibratory Driver/Extractor. 

C. HYDRAULIC HAMMER 

With the diesel engine running and the MAIN POWER switch ON, turning the 

hammer switch (FORWARD-REVERSE) to FORWARD energizes the hammer-start 

solenoid (V2A) on the DIRECTIONAL CONTROL valve.  The DIRECTIONAL 

CONTROL valve shifts, sending hydraulic oil to the hammer and the hammer 

begins to run.  Turning the hammer switch to the OFF position will stop the hammer 

from lifting again. 

D.  REMOTE - LOCAL CONTROL 

Located on the control panel.  Turning the LOCAL-REMOTE switch to LOCAL 

activates only the hammer and stroke control switches located on the control panel.  

Turning the LOCAL-REMOTE switch to REMOTE only permits operation of the 

hammer from the control pendant.  The EMERGENCY STOP button, on the 

pendant, is functional at all times. 

VI-2