US1918037A - Punch press guard - Google Patents

Description

y 1933. E. D. HOWELL 1,918,037

PUNCH PRES S GUARD Filed May 19, 1928 3 Sheets-Sheet 1 IV ENTOR A m/m0 flQ/Voh/HL.

ATTOR E July 11, 1933; E D HOWELL PUNCH PRESS GUARD Filed May 19, 1928 3 Sheets-Sheet 2 lNVENTOR TTORNE July 11, 1933. D E L PUNCH PRES S GUARD Filed May 19, 1928 3 Sheets-Sheet 3 INVENTOR gwvn/m Q Hon/ELL MTORNEY. i

Patented July 11, 1933 UNITED STATES r ."r ,rricn.

EDWARD D. HOWELL, 0F SPRINGFIELD GARDENS, ZNEVI" YORK, ASSIGNOR, BY ASSIGNMENTS, TO SPERRY GYROSCOPE COMPANY, INC 015 BROOKLYN, NEW YORK, A

CORPORATION OF NEW YORK PUNCH PRESS GUARD 7 Application filed May 19, 1928. Serial No. 279,091.

My invention relates to safety devices on power machines and is particularly designed in this case to guard the hands of the operator of a power press. The object of such a guard is to make it impossible for the opera tor to put his hands beneath the operating ram of such a machine. V 7

Accident records show that more injuries occur on power presses or punches than on any other machine, with perhaps one eXception,-the circular saw. In practically all press accidents the operators fingers are caught under the ram at the point of operation. This is due to (1) the press repeating, (2) the operator leaving hishand beneath the dies as the ram descends, or an unexpected stroke caused by accidental tripping of the treadle which serves to connect the ram to the power shaft.

One of the objects of my invention is the provision of a suitable guard, which when in effective position will prevent access by the operator to the operating element of the machine.

A further object of my invention is the provision of means whereby operation of the machine is prevented until the guard has been moved to effective position, thus pre venting accidental operation of the machine.

A further object of my invention is the provision of a guard of the type described, which may be actuated to effective and ineffective positions and which may be readily removed from. the machine if desired to permit certain classes of work, with which it might otherwise interfere, to be performed- Another object of my invention is the pro vision of a guard of the type described, which is adjustable to accommodate itself to work of various thicknesses and shapes.

In the accompanying; drawings in' which I have shown what I nowconsider to be the preferred form of the invention,

Fig. 1 is a front view of my invention applied to a power punch press.

Fig. 2 is an end view of the Fig. 1 device.

Fig. 3 is a View of a portion of the end opposite to that of. Fig. 2;

Fig. a is a view of another portion of the same end as Fig. 3, showing the power-operating shaft and the trigger for releasing the same.

Fig. 5 is a view similar to Fig. 4 showing.

a modified form of trigger control.

Fig. 6 is a front elevation of the guard or safety device on a larger scale than Fig. 1,

parts being removed for clearness.

Fig: 7 is a detail showing the/same parts as 2 but with the operating handle in a different position. I

I have illustrated my invention as applied to a power punch press but it'will be clear from the following description that it is capable of a much broader application than the one illustrated. Asshown, the guardis applied to the usual power punch press comprising the heavyl'ip-ri 'ht frame 5 support ing a- Crank shaft 6, having the usual power wheel 7. The crank shaft has suitably mounted thereon for reciprocatory movement a ram 8 adapted to have secured-thereto one member of the die 9, which is adapted to cooperate with the other member 10 of the die secured to a platform or baseplate 11' of themachine. The usual. trip lever treadle 12 is provided for operating the trigger 13 of the machine through connecting rods 14 whereby release of the trigger serves to clut lithe shaft 6 to the power drive 7 to operate the punch or rain.

The safety guard which I provide may be secured to the stationary frame 5 bymeans of a suitable bracket 15 supporting a shaft 16 to telescope within the arms and be locked therein in any suitable manner so as to allow the swingingguard frame 23, carried by said extensions, to cover completely the front of the lower die so' as to prevent the operator from putting his hands beneath the die or to permit the swinging frame to be raised to accommodate work of varying thickness and shape which projects outwardlybeneath said frame. The extensions 21 and 22 fit over suitable pins in the swing guard v23 and a spring member 2 holds them secure tosaid frame so that should it be desired to remove the guard it is only necessary to withdraw the said spring member.

The guard is normally held inthe ineffectlve position shown in full lines in Fig; 1.

' and in dotted lines in Fig. 6 byimeans such as a spring 32 fastened to face plate 17 and. en-.

gaging one of the supporting arms, 131111131 adapted to be moved to the effective position shown in dotted lines in Fig. 1 and in full line in Fig. 6. The means for operating the guard to effective position may comprise the shaft 16 to. which is secured hand-operated levers 25 and 26 on each end of the shaft to permit operation by either hand. One of said levers, such as 25, may be provided with a cam finger 27 (see Figs. 2 and 7 adapted to extend forwardly and engage a locking lever 28 pivoted upon plate 17. Said lever 28 may be provided with two arms 29 and 30, the latter having a link 31 connecting it to one of the swingingarms (here shown as arm 18), whereby said arms 18 and 19 and the guard 23 may be operated to effective position against the pressure of spring 32 which normally tends to maintain said guard in ineffective position.

As hereinbefore stated, it is one of the principal objects of my invention to prevent operation of the ram or punch unless or until the guard is in its effective position. To accomplish this ob ect, I provide a locklng means 40 in the form of a lun er normall pressed by a spring 41 into engagement with the lower side of trigger 13 to prevent release of said trigger when the operator steps upon the treadle 12 and draws down upon link 14. It willbe understood that the trigger normally abuts against the spring clutch member 52 on the crank shaft 6 and thus releases the shaft from the power wheel 7, but that as soon as the trigger is released from engagement with said member 52, the shaft 6 is connected to the power wheel and the ram or punch is operated. It will be understood that the spring 52 is normally maintained compressed by the rotation of the flywheel 7 with which the collar 152 has frictional engagement, and that as soon as the member 52 is released by the catch 13, spring 52 forces the catch forwardly, rotating the same and bringing a tooth thereon (not shown) into engagement with internal teeth (not shown) on the hub 7 of the flywheel. Such clutches are well known in the art and need not be further described. By providing the detent 40, I take the initial control of said clutch mechanism away from the treadle 12 and by connecting said detent 40 with the guard mechanism make the functioning of the clutch mechanism dependent upon the operation of the guard mechanism. For this purpose I have shown upon, shaft 16 an arm which fits into a slot 39 in the outer end of detent member 40 so that when handle 25 or 26 is operated to move the guard to its effective poistion the said arm 33 will be rocked and the detent 40 moved from under the trigger 13 until the point where the guard has reached its effective position, whereupon detent 40 will disengage trigger 13 to permit said trigger-to be actuated by operation of the treadle. Thus it will be seen that not until the guard has reached its effective position can the operator cause actuation of the press by stepping upon the treadle. Accidental operation of the press without the guard mechanism being in protective position. is thus rendered impossible. V a

In Fig. 5, I have disclosed a modified form of detent for preventing actuation of the trigger 13 by the treadle mechanism. In this form, instead of a spring pressed detent, I preferto employ a detent 40, which is one end of a bell crank 53, the otherarm 54 of which is weighted so as normally to main; tain the detent in looking position. The operation of the Fig. 5 form is in other respects the same as in the Fig. 4 form of the invention. In both forms the trigger is shown as operating between an upper limit stop 49 and a lower stop 50, the latter of which may be in the form of an adjusting screw 51 whereby to adjust the limit of downward movement.

For certaintypes of work continuous operation of the punch press is desirable and, therefore, I provide means whereby the guard may be maintained in its lowermost or effective position without the operator pressing down handles 25 and 26. For this purpose the lever carrying one of said handles, such as handle 25, may be provided at its opposite end with a nose or cam 34 which cooperates with a cam lever 35 having a han dle 36, which when operated downwardly to its lower positions, as shown in dotted lines in Fig. 2, or in full lines in Fig. 7 will cause the nose 34 to ride up on the face of cam 35 and thus operate guard 23 to lowermost position where it is maintained until handle 36 is raised.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of my invention, together withthe apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results ou lined, and the invention extends to such use. Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In an attachment for-machine tools having a driving shaft, an operating. member,

7 means including a trigger whereby said memsaid hard in inefiective )osition and means actuated by the movement of said guard into effective position for rendering said lastnamed means inoperative to permit release of said trigger by the operator.

' movable to effective and ineffective positions,

means normally maintaining said guard in ineifective position, and means actuated by the movement of said guard into effective position for rendering said trigger releasepreventing means inoperative to permit release of said trigger by said treadle.

3. An attachment for machine tools having a driving shaft, an operating member, and means including a trigger whereby said member may be connected to said shaft, comarising a guard for preventing access to said member by an operator, means for moving said guard to effective and ineffective positions, a wedge adapted to engage under said trigger to prevent release thereof, means whereby said wedge normally locks saidtrigger, and means whereby said guard operating means releases said wedge to disengage the same when said guard is moved to efiective position.

f. A power punch or the like having a driving shaft, a work-engaging member, means including a trigger whereby said member may be connected to said shaft, a guard for preventing access to said member by an operator, means for moving said guard to effective position, means normally maintaining said guard in ineffective position, a locking means normally engaging said trig- I ger to prevent its release, and a handle to move said guard to its operative position to release said locking means thereby permitting said trigger to be operated by the normal punch operating mechanism only when the guard is in the effective position.

5. In combination, a. machine having a driving shaft, an operating member, means including a trigger whereby said member may be connected to said shaft, springpressed means normally maintaining said trigger in position to prevent said connection, a guard for preventing access to said member by an operator means for moving said guard to effective and ineffective positions, locking means directly engaging said trigger whereby release of said trigger is prevented if said springpressed means fails, and means whereby said guard operating means actuates said locking means to disengage the same from said trigger when said guard is moved to effective position.

6. In combination, a machine having a driving shaft, an operating member, means including a trigger whereby said member may be connected to said shaft, springpressed means normally maintaining said trigger in position to prevent said connection, a guard for preventing access to said member by an operator means for moving said guard to effective and ineffective positions, locking means directly engaging said trigger and interposed between said trigger and said spring-pressed means whereby release of said trigger is prevented if said springpressed means fails, and means whereby said guard operating means actuates said locking means to disengage the same from said trigger when said guard is moved to effective position.

7. A power punch or the like having a driving shaft and a work-engaging member, means including a trigger whereby said member may be connected to said shaft, a treadle adapted to be actuated by the operator for releasing said trigger, a lock normally preventing release of said trigger by said treadle, and a handle adjacent the work for temporarily releasing said lock whereby said means is only operated when both said handle and treadle are operated.

8. A power punch or the like having a driving shaft and a work-engaging member,

'means including a trigger whereby said member may be connected to said shaft, a treadle adapted to be actuated by the operator for releasing said trigger, a lock normally preventing release of said trigger by said treadle, a handle adjacent the work for temporarily releasing said lock whereby said means is only operated when both said handle and treadle are operated, and means for locking said handle down for continuous operation through the treadle.

9. A power punch or the like having a driving shaft and a work-engaging member, means whereby said membe may be connected to said shaft, a guard for preventing access to said member by an operator, means for pivoting the guard above the work whereby it may be swung to one side of and above the work in its ineffective position, means for normally maintaining said guard in such ineffective position, manual means for moving said guard to effective position, and means whereby said first-named means is maintained inoperative until said guard is in its effective position.

In testimony whereof I have aiiixed by signature.

EDWARD D. HOWELL.

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