Control system for a punch press

Claim 2

A punch press control system wherein a pair of push buttons must both be depressed to complete a first electric circuit which, when completed, causes operation of means for moving a bolster plate of the punch press from a loading to a work position, limit switch means responsive to the bolster plate reaching the work position partially completes a second electric circuit which, when completed, causes operation of a means for effecting reciprocation of a ram of the punch press through one cycle, and release of both push buttons completes the second circuit, said system being characterized in that time delay means are provided to prevent completion of the second circuit if the release of one of the push buttons is delayed beyond a predetermined time after release of the other push button.

Claim 3

A punch press control system as claimed in claim 1 wherein the system includes a relay having a coil in a circuit energized concurrently with the first circuit and a normally open contact in the second circuit, said contact closing upon energization of the coil, said coil being associated with the time delay means thereby to delay deenergization of the relay coil upon opening of the first circuit.

Claim 4

A punch press central system as claimed in claim 2 wherein the time delay means includes a diode and a capacitor connected in series and parallel, respectively, with the coil.

Claim 5

In a control system for a punch press of the type having a bolster plate reciprocatable between a loading position and work position and a ram reciprocatable through a cycle from a first to a second relatively displaced position and back to the first position, said control system comprising: first, second and third electromagnetic relays each having an energizing circuit; a bolster-in solenoid having an energizing circuit and operative when energized to cause the bolster plate to move from the loading position to the work position; a bolster-out solenoid having an energizing circuit and operative when energized to cause the bolster plate to move from the work position to the loading position; a ram solenoid having an energizing circuit and operative when energized to cause the ram to reciprocate through said cycle; a pair of depressible and releasable push buttons each having a normally open and a normally closed contact, the normally open contacts of the push buttons being connected in series with each other in a circuit forming part of the energizing circuits for the first and second relays and the bolster-in solenoid, the energizing circuits for the first and second relays being completed upon closure of the normally open contacts of both push buttons when the bolster plate is in the loading position; a normally open contact of the first relay in the energizing circuit for the bolster-in solenoid which contact when closed completes the energizing circuit for the bolster-in solenoid through the normally open contact of the push buttons when those contacts are closed and the bolster plate is not in the work position; the normally closed contacts of the push buttons being connected in series with each other in a circuit forming part of the energizing circuits for the third relay and the ram and bolster-out solenoids; a normally open contact of each of the first and second relays being connected in series with each other in a circuit forming part of the energizing circuits of the ram solenoid and the third relay; a normally open contact of the third relay being interposed in the energizing circuit for the ram solenoid; the energizing circuit for the third relay being completed when the normally closed contacts of the push buttons are closed and The first and second relays are energized and the energizing circuit for the ram solenoid being completed upon energization of the third relay; normally closed of the second and third relays being in series with each other in the energizing circuit for the bolster-out solenoid and in series with the normally closed contacts of the push buttons, the improvement which comprise means to provide a time interval in the drop-out of the second relay so that both push buttons must be released simultaneously or within a predetermined time of each other to open their normally open contacts and to close their normally closed contacts thereby to cause energization on the ram-solenoid.

Claim 6

In a control system for a punch press of the type having a bolster plate reciprocatable between a loading position and work position and a ram reciprocatable through a cycle from a first to a second relatively displaced position and back to the first position, said control system comprising: first, second and third electromagnetic relays each having an energizing circuit; a bolster-in solenoid having an energizing circuit and operative when energized to cause the bolster plate to move from the loading position to the work position; a bolster-out solenoid having an energizing circuit and operative when energized to cause the bolster plate to move from the work position to the loading position; a ram solenoid having an energizing circuit and operative when energized to cause the ram to reciprocate through said cycle; a pair of depressible and releasable push buttons each having a normally open and a normally closed contact, the normally open contacts of the push buttons being connected in series with each other in a circuit forming part of the energizing circuits for the first and second relays and the bolster-in solenoid, the energizing circuits for the first and second relays being completed upon closure of the normally open contacts of both push buttons when the bolster plate is in the loading position; a normally open contact of the first relay in the energizing circuit for the bolster-in solenoid which contact when closed completes the energizing circuit for the bolster-in solenoid through the normally open contact of the push buttons when those contacts are closed and the bolster plate is not in the work position; the normally closed contacts of the push buttons being connected in series with each other in a circuit forming part of the energizing circuits for the third relay and the ram and bolster-out solenoids; a normally open contact of each of the first and second relays being connected in series with each other in a circuit forming part of the energizing circuits of the ram solenoid and the third relay; a normally open contact of the third relay being interposed in the energizing circuit for the ram solenoid; the energizing circuit for the third relay being completed when the normally closed contacts of the push buttons are closed and The first and second relays are energized and the energizing circuit for the ram solenoid being completed upon energization of the third relay; normally closed of the second and third relays being in series with each other in the energizing circuit for the bolster-out solenoid and in series with the normally closed contacts of the push buttons, the improvement which comprise means to provide a time interval in the drop-out of the second relay so that both push buttons must be released simultaneously or within a predetermined time of each other to open their normally open contacts and to close their normally closed contacts thereby to cause energization on the ram-solenoid.