Part revolution mechanical press
Revolution Clutch, as defined by OSHA, [29
CFR 1910.211(d)(6)], is a
type of clutch that can be disengaged at any point before the
crankshaft has completed a full revolution and the press slide has
The majority of part revolution presses are air clutch and brake.
They are designed to trap air in a chamber or tube. When compressed
air is put into these chambers, the clutch is engaged and
the brake is disengaged. The press then makes a single stroke. To
stop the press, the reverse takes place.
This type of press is not as dangerous as the full
revolution clutch press. However, hazards still exist. Here, the operator must keep the operating controls depressed
throughout the machine stroke. A release of either
control will stop the press action.
Many older models of part
revolution clutch presses use a mechanical-friction clutch. These types of presses are generally not as safe but can be updated by adding a properly sized air
cylinder to the part revolution control.
For a printable sample form of a periodic inspection record for
partial revolution power presses, please see Appendix
The biggest hazard when
working with either full or part revolution mechanical power presses
is the point of operation. A hand or any body part in this
result in crushed or severed limbs or even fatalities.
The following are OSHA and ANSI
recognized methods for safeguarding the point of operation on part
revolution clutch mechanical power presses: