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Series 1999SEMC Semelex® Safetimeter
6380 Brockway Rd, Peck, Michigan 48466 • Phone: 248-435-0700
3.9: Set Press Counterbalance
The Gemco Semelex II Safetimeter has the capability of checking both down and up stop times to aid in setting the
press’s counterbalance. For best results, the down stop time test should be initiated at 90 degrees and the up stop
time test at 270 degrees. It is important to stop the ram before engagement of the dies on the down stroke, and
before top dead center on the up stroke. However, on some presses, the ram may take longer than 90 degrees to
come to a complete stop. Test this condition as follows:
1. On the downward stop time test, increase the Control Start Point (CSP) setting to initiate a stop between 0 and 90
degrees. Continue increasing the CSP and testing the press until a down stop of the ram can be made before the
dies have fully engaged.
2. On the upward stop time test, decrease the CSP setting to initiate a stop between 180 degrees and 270 degrees.
Continue decreasing the CSP and testing the press until an upward stop of the ram can be made before the top
stop.
NOTE: It is important to test both the down and up stop times using the same press control. Typically, an inch
button or two-hand control in the inch mode will be used since an up stop time test is not possible in the single
stroke mode using a two-hand control. Adjust the counterbalance to obtain equal down and up stop times. This
sets the counterbalance at the optimum point. Always follow the press manufacturer’s recommendations when
setting the counterbalance. Several safety distance and/or stop time tests must be performed after the setting of the
counterbalance to ensure safe press operation and guarding.
3.10: Test Full Revolution Clutch Presses
Calculating the safety distance of a full revolution clutch press per OSHA 29 CFR 1910.217(c)(3)(viii)(c) is as follows:
Dm=63 inches/second x Tm; where:
Dm=Minimum safety distance (inches);
63 inches/second = hand speed constant:
and
Tm = the maximum time the press takes for die closure after it has been tripped (seconds). For full revolution clutch
presses with only one engaging point, Tm is equal to the time necessary for one and one-half revolutions of the
crankshaft.
For full revolution clutch presses with more than one engaging point, Tm shall be calculated as follows:
Tm = [1/2 + (1 / Number of engaging points per revolution)] x time necessary to complete one revolution of the
crankshaft (seconds).
The Safetimeter can aid in calculating safety distance of a full revolution clutch press by measuring the time
necessary to complete one revolution of the crankshaft.
Perform the following steps:
1. Set the FULL REV/PART REV switch to FULL REV.
2. Set the TIME UP/TIME DOWN switch to TIME UP.
3. Set the STOP TIME/SAFETY DISTANCE switch to STOP TIME.
4. Position the P/V transducer as described in Section 3.1: Placement of Position/Velocity (P/V) Transducer.
5. Push the Safetimeter power switch to ON.
6. Cycle the press. The Safetimeter will begin counting when the ram begins to travel down and will stop counting
when the ram stops on the up stroke. The Safetimeter will display the time for one stroke of the press.
