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THE BASIC PRINCIPLE - The Junkin Guard is based on the principle of the interlocking switch which is familiar to most of us. The basic provision of this principle being that one mechanical motion must be complete before the second is at all possible. One of the most common applications of this principle is the elevator or subway door which must be closed before it is possible to start the car in motion. Applying this principle to the Junkin Guard, the gate must be completely down in a protective position before it is possible to trip the press. Thus a hand in the danger zone prevents the gate from reaching the complete protective position and acts as a key which locks the interlock and prevents the press from being tripped.

Three major assemblies combined with various small fittings and rods make the Junkin Guard one of the most unique and simple devices for the protection of press operators.

THE INTERLOCK - The mechanical interlock is interposed between the foot pedal and the clutch mechanism of the press. It controls the action of the barrier gate and is in turn controlled by the position of the gate. It acts as a positive lock on the clutch mechanism except when the gate is in the complete protective position. The non-repeat feature of the Junkin Guard is an intrinsic part of this assembly.

THE BARRIER GATE - The reciprocating barrier gate which is mounted on a pivot shaft through the press frame is controlled by a interlock and lifter disc and controls by its position the action of the interlock. It falls vertically by gravity from the latched position to the protective position before the point of operation, remains in this position during the working stroke of the ram, and is then raised by the lifter disc to the original latched position.

THE LIFTER DISC - The lifter disc assembly is mounted on the left hand end of the main crankshaft. It serves primarily as a means of raising the barrier gate from the protective position to the latched position. Through the action of the gate it controls the action of the non-repeat mechanism.

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