J&M 220 Operating And Maintenance Manual - page 30

MODEL 220 

HYDRAULIC 

IMPACT HAMMER 

III. OPERATING 

INSTRUCTIONS 

E.  OPERATION OF THE HAMMER (CONTINUED) 

4. Stroke 

Setting 

Stroke setting is controlled by the CLAMP OPEN-CLOSE switch.  The full stroke 

mode is the normal hammer mode.  The hammer will run in at any stroke length 

as long as the clamp switch remains in the middle, neutral position.  To reduce 

stroke setting, turn the clamp switch to the OPEN position briefly.  This will 

extend the variable stroke cylinder shortening the stroke.  When stroke is at the 

length required, release the clamp switch.  The switch will spring return to its 

neutral position.  To lengthen the stroke turn the clamp switch to the CLOSE 

position briefly.  This will retract the variable stroke cylinder lengthening the 

stroke.  When stroke is at the length required, return the clamp switch to its 

neutral position.  The stroke length may be changed while hammer is in 

operation. 

The operation of the hydraulic hammer can be controlled directly from the 

control panel, by the remote-control pendant or with the radio control unit.  

These control locations have identical switches for hammer stop/start, egine 

RPM and stroke setting. 

The hammer is controlled by three, two-way switches.  These switches are 

labeled CLAMP OPEN-CLOSE, FORWARD-REVERSE and FAST/SLOW.  The 

switches are labeled in this manner because  Model 175 also operates J&M 

Earth Augers and Vibratory Hammer. 

III-5