GB707089A - Improvements in or relating to movable back gauges for cutting machines - Google Patents

Abstract

707,089. Control of two motors. LAWSON, CO., Inc., E. P. Aug. 29, 1951, No. 20433/51. Class 38(3) [Also in Groups VIII and XL(b)] Two motors 34, 36, Fig. 2, are used to drive a feed member for moving a paper stack intermittently to cutting position in a guillotine cutting machine (see Group VIII), the motors being controlled by photo-electric means and operating through sun-and-planet gearing so as automatically to move the stack at high speed until near cutting position and then at low speed until it is stopped for the cut to be made. The feed member 61, Fig. 1, is engaged by a screwed spindle 10 which is rotated by the gearing comprising two sun gears 16, 25 meshing with two sets of planetary pinions 14, 15 carried on an arm 12 keyed to the spindle. The gear 16 is connected to a casing 19 carrying a pulley 22 driven by a belt 35a from the twospeed reversible motor 36, and the gear 16 is connected to a pulley 27 driven by a belt 33a from the reversible motor 34. The motor 34 also drives a pulley 39 on a shaft 40 journaled in an arm 45 suspended from the bushing 30 of the spindle 10; a clutch gear 43, normally clutched to the shaft 40 by a clutch member 47 operated by a solenoid 51, gears through an idler 55 with a gear 57 connected by an over-running clutch 59 with the pulley 22. As the motors are being brought to a stop during forward movement of the feed member, the clutch 59 provides for the gear train 43, 55, 57 to act with a braking action upon the motor 36 and by preventing its speed dropping more rapidly than that of the motor 34 avoids any reversal in the direction of drive of the spindle 10. A clutch 60 provided between the gears 16, 25 similarly prevents the motor 34 from over-running the motor 36 when they are coming to a stop in the reverse direction. The photo-electric device comprises a light source 79, Fig. 1, and light sensitive medium 78 which are mounted on a carriage 63 movable relatively to an apertured or other control strip 80 by a cable connected with the feed member 61. In operation, each forward step of the member 61 is initiated either by the depression of a push button or automatic closure of a switch at the end of the return stroke of the knife so as to complete a circuit whereby the motors move the feed member and photoelectric device forward rapidly until the light beam is intercepted by an aperture or other control indication 81 on the control strip. The circuit is then automatically adjusted to effect drive of the motor 36 at slow speed while the motor 34 continues as before and the feed member and photo-electric device move forward slowly until the control indication is no longer effective to pass the light beam. At this stage, a circuit including a plugging switch 37, Fig. 2, adapted to be closed when the motor 36 is operating, causes the terminals of the motors to be reversed to bring about a rapid retardation of their speeds; when the motor 36 reaches a predetermined low speed, the switch 37 automatically opens and the motors stop. When, after a succession of cuts, the feed member has reached its most forward position, it can be returned by depressing a reverse button to operate the motors in reverse, the solenoid 51, Fig. 4, being automatically energized to disengage the clutch member 47. The actuation of a reverse limit switch when the feed member reaches its initial position again causes the motor terminals to be reversed and the plugging switch opens to bring the motors to a stop. Specification 707,090, [Group VIII], is referred to.