초록 ▼

A controller for an electric clamp closes the clamp rapidly at first, then runs at a slower speed while contacting the workpiece, and speeds up again after contacting it, to close with full clamping force. Arrival of the clamp at the position for slowing down is directly detected by means of a proxi

A controller for an electric clamp closes the clamp rapidly at first, then runs at a slower speed while contacting the workpiece, and speeds up again after contacting it, to close with full clamping force. Arrival of the clamp at the position for slowing down is directly detected by means of a proximity sensor, as are arrivals at other positions. The speed of operation is relatively insensitive to the voltage of its AC electrical power source because an open-loop compensating signal controls the pulse duration of rectified DC pulses that drive the motor. The controller has dynamic braking that is applied between individual pulses of pulse trains of motor current; this results in sigfificant increase in swings of current values for a given motor speed, that reduces harmful effects of mechanical friction. Two jogging speeds are selectable.

대표청구항 ▼

A controller for an electric clamp which is driven open and closed by an electric motor to which power is connected upon commands, comprising in combination: (a) means responsive to a command to close the clamp, for providing high-speed travel during a run-up in the closing direction; (b) proximity

A controller for an electric clamp which is driven open and closed by an electric motor to which power is connected upon commands, comprising in combination: (a) means responsive to a command to close the clamp, for providing high-speed travel during a run-up in the closing direction; (b) proximity sensing means for directly detecting when the clamp reaches a predetermined position, and for initiating thereupon an interval during which the speed of travel is lower; (c) means for terminating the lower-speed travel after a predetermined time; (d) means for providing higher power to the clamp thereafter during completion of its closing; (e) sensing means for directly sensing that the clamp has reached a closed position and for interrupting power flow to the motor thereupon.