US2777518A - Machine tool - Google Patents

Description

Jan. 15, 1957 H. NADERHOFF MACHINE TOOL Filed Feb. l2, 1952 QQQL .mllhbl (lvm United States Patent Gf 2,777,518` Y' MACHINE TOOL Heinrich Naderhoif, Goppingen, Wurttemberg, Germany, assignor to L. Schuler A. G., Goppingen, Wurttemherg, Germany Application February 12, 1952, Serial No..271,125 Claims priority, application Germany March 1, 1951 Claims. (Cl. 164-50) ment, are also'started by hand, and iinallythe tool and the work feed are brought to rest after completed workk operations.

The present invention, however, consists in providing A an electrical control system having a press button startblank, in the case of a groove 'punching machine, a fast return travel of the guide frame for the work blank, and lautomatic switching olf means for the fast return travel ing switch for switching on a power driven fast return f travelof the feed means after the insertion of a work when said feed means reaches its end position, automatic f switching on means for the tool movement and means dependent on said movement for the stepwise work feed at the end of a work operation. The great manual exertion required for the return movement of the feed means, in the case of groove punching machines, the holder frame, vand the manual starting, are all overcome by the electrical control system'according to the present invention. The. starting now takes place without any physical strain by mere Iactuation of an electrical hand or pedal switch, whereupon the return travel of the feedl means to its initial position and its reversal take place automatically, Machines inv accordance with the invention are therefore most suitable for loperation by younger and unskilled operators, particularly lesser physical strength.

young persons of According to another feature of the invention, the

power drive means for the fast return travel comprises an electric motor, a -disc coupling actuated by an; electromagnet in rdependency on the control system to engage and disengage `said motor, and means for operating said electromagnet including a circuit breaker and yindependent switch-on and switch-off press-button switches. The invention also comprises the inclusion inthe sys- 20 moves in the direction of the arrow 20.

phase vnetwork RST, through fuses 5, an electric motor 'i The press button switch 3 serves for switching on and p the switch 4 for switching off th-e motor 1.

The motor drives, through an electromagnetically koperated plate clutch 6, a shaft 37 and al pinion 3S, the

diagrammatioally indicated work carrier 7 ofthemachine and guides it back into the starting position shown in broken lines. For the purpose of operating the clutch 6, there are a push-button switch 9, y.an eng-aging relay 8, a transformer 1li, and a rectifier 11. An electromagnet 12, which is switched on when the relay is closed, is falso connected to the engaging relay 8. The armature of this magnet is in operative connection, through a rod system (not shown), with a rod 2l) in such manner that when the magnet 12 is switched on the rod 20 is so connected, through a locking rod system consisting of a `two-armed lever 31, 32 rockably mounted locks the feed device in the advanced position, that when the magnet 12 is switched on the locking is cancelled.

A limit switch 13 is provided at the end of the return travel of the feed means, which switch 13 is connected tothe `circuit breaker S and also to a magnet 14 controlling the tool movement andthe work feed movement. This magnet 14 is operatively connected to a rod which transmits the movement to operate a second switch-off magnet 17. To the rod there are connected two switches 15 and 18 in such a manner that the switch 15 when the rod is in disengaged position is inthe switchon position and at the same time the switch 18 is held in switch-off position, whereas when the rod is in engagement the switchl 15'is held in switch-off position and the switch 18 in switch-on position. IThe switch 15 lies in ythree-armed lever receives an oscillating movement from 'a cam 22 which makes one rotation with the shaft 29 during lthe punching of each groove. The arm 26 of the three-armed lever carries a roller 27 engaging the periph-ery of the cam 22. This cam 22 is also provided in one side'face with a cam groove 23 controlling a switch 21 in such a manner lthat the switch is held closed during the angle `ofrotation determined by the groove tem of a circuit breaker actuated by the switoh-onpressf button switch, said circuit breaker controlling the fast return travel coupling, for example, by means of a transformer feeding t-he coupling actuating the electromagnet througha rectifier, and a magnetic release means for a locking `device adapted to hold the work feed means in its working and end positions, the larrangement being such that the circuit breaker receiv-esoperating voltage over a switch dependent onthe tool engaging and disengaging movements, which switch is closed. when the drive` ofthe tool tand of the work feed means is disengaged.rv

Further features will beapparent rfrom the following description in conjunction with 'the claims and thedrawing which illustrates diagrammatically the control system faccordingto the present invention. v 'f In the system illustrated there is connected to a three- 23.l The rod 20 in operative connection with the magnet 12 also acts on the arm 24 of the three- armed lever 24, 25 and 25, which is mounted to rock 4about pivot 28. The arm 26 of the three-armed lever bears through the roller 27 against the periphery of the cam disc 22, Which turns once with the crankshaft driving the ram 39 during-.the kstamping-out of a slot and imparts a pendulum movement to the three-armed lever24, 25 and 26. On

the crankshaft 29 a crankdisc 40 is fastened, by which a lp-awl ratchet mechanism 41 is driven for the stepwise advance of the guide frame 7.

The operation ofthe saidV system is as follows:

In the villustrated position of the parts, the work feed means is in its foremost position in which the guide frame 7 of the feed means holds the limit switch 16 closed. 'Ihe rod for actuating the work feed and the tool move- Patented'Jan. 15, 1.957

The rodl 3 ment is in disengaged position, so that upon the closing of the switch 1S the circuit breaker 8 is pre-set for actuation. Before the switch-on switch 9 is closed, the motor 1 is switched on by the press button 3 over the circuit break-y er 2, which is Yshown in switch-cti position. The motor movement is`at .first not transmitted further becausefthe,4 disc coupling 6 -is open. `By closing the `switch 9 they electromagnet which energizes 'the-disc coupling over y end of the lfast return stroke, the frame 7 actuates the limit switch 13 whereby the circuit breaker 8 is de-energized and returns into `its switch-off` position so that the coupling 6 is again de-energized. The limit switch 13 also energizes the engaging magnet 14 so thatY now the stepwise operating work feed and tool movement are initiated. At the beginning of the work stroke the switch 13, for example by the ,action of a spring not shown, returns to the illustrated position in which the closing of the circuit breaker 8 again becomes-possible. When mechanism after insertion of a `blank workpiece, and means operative for automatically switching-on the high speed return and then switching-off the high speed return on reaching the end position, automatically switching-on the drive for a tool and, dependently thereon, the intermittent working feed.

2. An electrical control Aarrangernent according to claim l, wherein an electric motor is provided for the power I drive for the high speed return and adapted to be coupled such closing takes place, `the switch 15 is opened, and

the switch 18 closed. The closing of the switch 18 prepares for the actuation of the disengaging magnet` 17. This takes place when the frame 7 at .the end of its work stroke again closes the limit switch 16, or when the switch 21 .inparallelvwith the switch 16 is closed by the action of the cam groove 23, as long as the rod 20 occupies a position in which the switch 19 also `is`closed.

This is the case when the locking means forthe feed means, which is actuated by the rod 2G and, forexample,

may consist of a holder pin, has nct `arrived in the loclr- Y.

ing position.` The cam groove 23 `holds theiswitch 21 closed for a time corresponding tothe period cf locking; on unlocking, the rod 20 is shifted in the direction'V end of this punch feed, the cam disc 22 is again in the angular position which permits the' retraction of the rod l 20 and simultaneous engagement of the locking means. Should the locking means fail to operate so that the rod 20 does not return, then the switch 19 would still be` closed and the switch 21 would be closed byv the 4cam groove 23, and thereby the disengaging magnet 17 energized. The parts 19and 21 to 2S thus constitute a safety device preventing operation of the punching when the feed means is not locked.

The magnet 17 when itfis energized by the lim-it switch A 16 .or overthe safety switch 19, disengages the feed means i and the tool movement. If the disengaging magnet is energized by the limit switch 16, then the parts, after the disengagement, are returned to the illustrated position, except for the still running motor 1. After insertion of `a new blank in the guide frame, closing the switch 9 will initiate a new work operation inthe manner hereinbefore described.

I claim: l, l. An electrical control `arrangement for a `slotting or` the like machine of the kind in which a worl: carrier or feed mechanism therefor `is moved back to a starting position afterrthe completion of a pre-determined numberof intermittent slotting `or punching work operations, comprising a push button switch for switching-on a pc-wer driven high speed return of the work carrier :or feed and uncoupled through a plate clutch operated electroi magnetically in dependence on the control arrangement, said motor being adapted to be switched on and ott` through a relay operated by independent switching-on and switching-olf buttons.

3. An electrical control arrangement according to claim l, wherein an electric motor is provided for the power drive for thehigh speed return and adapted to be coupled and uncoupled through a plate clutch operated electromagnetically in dependence on the control arrangement, said motor being adapted to be switched on and ofi through` a relay operated by independent switching-on and switching-off b-uttons, and in which-a switch relay is provided operated bythe engaging switch and by means of which the high speed return `clutch is controlled feeding the clutch magnet withxt-he aid of a rectifier, and in which aA magnetic release device is provided for a locking means holding the feed device in the working and end positions, while `the working voltage is supplied to the switch relay through a switch dependent on the engagement and disengagement ofthe tool, said last-mentioned switch being closed when the drive of the tool and ofthe working feed is disconnected.

4. A-n electrical control arrangement according to claim 1, wherein an electric motor is provided for the power drive for the high speed return and adapted to be coupled and uncoupled through a plate clutch operated electromagnetically in dependence on the` control arrangement, said motor being adapted to be switched on and ot through a relay operated by independent switching-on and switching-off buttons, and in which a switch relay is provided operated by the engaging switch and by means of which the high speed return clutch is controlled feeding the clutch magnet with the Vaid of a rectifier, and in which a magnetic release device is provided for a locking means holding the feed device in the working and end positionsfwhile lthe working voltage is supplied to the switch relay througha switch dependent on the engagement and disengagement of the tool, said last-mentioned switch being closed when the drive of the tool and of the Working feed is disconnected and a second switch provideddependent on the engagement and disengagement of the tool including the switch by which the engaging relay is `connected to voltage when disengagement occurs, said additional switch being closed in the engaged posi- `tion and is in the circuit of a disconnecting magnet so that the latter becomes operative as soon as further switches inthe same circuit are closed including a switch automatically closed by the `feed* device at the end of the workcycle.

5. `fnzcelectrical control arrangement according to claim 1, wherein an'electric motor is provided for the power drive for the high speed return and adapted to be coupled and uncoupled` through a plate clutch operated electromagnetically in dependence on the control arrangement, saidmotor being adapted to be switched on and off through a relay operated by independent switching-on and switching-olf buttons, and in which a switch `relay is provided operated by the engaging switch and by means of which `the high speed return clutch is. controlled `feeding the c lutch magnet'withthe' aid of a rectifier, and in which a magnetic release deviceis provided for a lock ing means holding the feed device in the working and end positions, while the working voltage is supplied to the switch relay through a switch dependent on the engagevment and disengagement of the tool, said last-mentioned switch being closed when the drive of the tool iand of 'che References Cited in the le of this patent working feed is disconnected, and a switch operated by UNITED STATES PATENTS the feed device at the end of lthe high speed return of 1 257 507 Malocsay Feb' 26 1918 the latter provided for a magnet effecting the engagement 638:662 Rothwell May 19 1953 of the tool and working feed drive `and at the same time 5 releases the engaging relay.

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