US2014758A - Safety device for punch presses - Google Patents

Description

Sem. M, w35.' P. E. BOYD SAFETY DEVICE FOR PUNCH PRESSES Filed July 24, 1933 #WE/v faq- UNITED STATES YPATENT OFFlCE SAFETY DEVICE FOR PUNCH PRESSES Percy E. Boyd, Detroit, Mich.

Application July 24, 1933, Serial No. 681,957

'7 Claims. v(01.192-24) It is a well known fact that there has always existed a great difficulty with the operation of punch presses in general, which not only increases `the cost of operating and maintaining this class of machinery, but the diiiculty is likewise unreliable and dangerous for the operator.

As the press begins to wear after prolonged use and due to the present construction, the square corners of the jaws of the bull gear and likewise the jaws of the clutch head of the'press become rounded from repeated engagement of these elements, and the corners of the jaws of the clutch being rounded will have a tendency to engage the jaws ofthe bull gear continually when the latterris idling and with a ypronounced.

clattering or pounding eiect, thereby causing a rapid wear and rounding of Aall corners of both sets of jaws, and to an extent whereby all of the jaws must be removed and replaced with new ones, which requires considerable delay and expense at regular intervals for this purpose.

With this difliculty also, the crank of the press will not be caused to stop precisely at high dead center, as it should do when the same is operating correctly, on the contrary the crank will stop approximately from ve to-fteen degrees before high dead center is reached. This condition prevailing the crankwill have the tendency to, andl very frequently does drop to low dead center, simultaneously operating the press at an unex- ,pected time'and without warningY to the operator,

and if the operators hand would happen to be near the dies a serious accident could not be averted.

The principal object of thisinvention is to provide a device that is coordinatedwith the trip mechanism of the press, for the purpose of retaining adequate clearance intermediate the jaws of the clutch head and the jaws of the bull gear at all times when 'the press is idling, and as the square cornersvof both sets of jaws begin to Wear,

Van adjustment is pro-vided to overcome the extent of this worn condition, which is in a positive manner so that the press will operate smoothlyY with safety and greatly prolong the life of the jaws,`thereby effecting a decided economy in repeated loss of time and expense in the general o-peration and maintenance of this class of machinery.

The invention possesses further'advantag'es, all of which will be obviously apparent during the vcourse of the following detailed description, illustrated throughout `the accompanying drawing, Yand more fully pointed out in the appended claims.. Y Y

'end of coil spring 8.

With reference to the drawing:

Figure 1 is a reduced View of a portion of a punch press showing the same equipped with the device and indicating the proper clearance intermediate the jaws of the clutch head and the jaws 5 of the bull gear.

Figure 2 is a similar reduced sectional view, showing lthe device in the act of releasing the jaws of the clutch head from those of the bull gear. Y 10 Figure 3 is a front elevation of the device and showing the same secured to the trip bracket of the press.

Figure 4 is Y a full size longitudinal section through the center of one of the principal units 15 of the device. l

Figures 5, 6 and 'l are greatly enlarged sections of both sets of jaws of the press, and Figure 5 clearly indicating the sharp corners of the jaws when they are new and Vnot worn; Figure 6 dis- 20 'closes a worn condition of the jaws, and Figure 'l shows an advanced state of worn jaws, or approximately the limit to this extent.

In the following the letters will indicate various Yelements of the press, while the numerals will 25 have reference directly to the respective portions V which is adapted to engage a similar threaded 'aperture 3 within machined face A of press frame B. `The opposite end of said stud also has an externally threaded portion as at fl, which is 'adapted to engage a similarly threadedv elongated 40 sleeve 5, with preferably a castellated nut 6 where clearly indicated in Figure 4.

It is Valso observed that sleeve Eis provided with flanged head l so as to accommodate one Said spring is operatively 45 disposed over stud l, the opposite end of the spring bearing upon freely disposed collar 9 upon the said stud. Trip bracket C is a part of the press and is altered for coordination with the Vinvention by providing openings Ill therethrough, 50 and said openings being of a somewhat greater diameter than studs l so as to accommodate the tilting motion of the bracket relative to press frame l5N duringthe operation ofthe device. said studs being permanently xed with frame B. 55

Referring to Figures 5, 6 and '7, D indicates the jaws of clutch head E, and F likewise indicates the jaws of bull gear G, and in Figure 1 the portion of the press shown in the view indicates a press having new jaws in the clutch head and bull gear and normally having sharp corners as shown in Figure 5. In Figure 2 trip bracket C is shown actuating cam H and in the act of releasing or disengaging jaws D from jaws F. It is to be understood that when jaws D and F are new and with sharp corners, coil springs 8 are closely compressed, and in the degree that both sets of said jaws become worn, as for example the illustration in Figure 6, the compression of springs 8 is released by backing nuts S of the four units uniformly, thereby releasing the respective sleeves 5 which oppose the tension of said springs. The major purpose of springs 8 is to provide therein ample tension to resist or overcome the tension of springs J within clutch head E, and in this manner and with the proper adjustment of springs 8, consistent with the worn condition of jaws D and F, springs 8 will positively cause clutch head E to be positively and promptly disengaged from bull gear G at the precise instant when crank K of crank shaft L is at high dead center; thus the press is safely in a neutral position while bull gear G remains idling. In accomplishing this purpose ample clearance is obtained intermediate jaws D and F at all times when the press is neutral and said bull gear idling.

In the normal operation of the press it is understood that cam H automatically disengages the clutch by virtue of its operative relation with roller N, and when the press is idling the jaws of the clutch head and the jaws of the bull gear are positively cleared as in Figure l. If the jaws are worn there is nothing to prevent the jaws of the clutch head from lagging against the jaws of the bull gear and trying to force entrance therein because of the pressure exerted upon the clutch head jaws by springs J. Inasmuch as springs 8 are compressed to maximum tension when the jaws are new and unworn, and that they are very much more powerful than springs J, in this condition there is a xed relation between the tension of both sets of springs referred to, and it is here to be emphasized that this relation is disturbed in the degree that the jaws are worn. As the jaws wear springs J become elongated, tending to force jaws of the clutch' head to meet jaws of the bull gear, consequently it is necessary to release springs 8 by backing olf nuts 6, thereby releasing sleeves l, so that springs 8 will compensate for the changed tension of springs J brought about by the wearing of the clutch jaws, and in this manner the relation between the tension of springs 8 and springs J will be maintained same as when the jaws are new as previously described.

In the use of this device the press becomes dependable, accurate and safe at all times, which is an important improvement and advantage in the operation of the same.

Another marked advantage of the invention is that in view of the extreme simplicity thereof, the same may be installed in connection with the press for a remarkably low cost in time and material, and the invention being very substantial in construction, the same should satisfactorily endure for an indenite period, consequently effecting a decided saving in tima-material and delay.

It may be Well to state herein that the invention is a proven discovery, in that several presses .of said studs, the unxed end of said studs have been equipped with this device and have been in continuous operation for a period of eighteen months, and upon examination of jaws D and F it was revealed that the square corners of the same were almost intact, or free from 5 wear, and during the entire period all clattering or pounding of the jaws as previously explained, was unknown.

It is of course further understood that wearing of the corners of jaws D and F is occasioned 10 by reason of worn elements of the press, such as roller N and cam H, and in this worn condition the customary trip bracket used fails to disengage jaws D from jaws F to provide a proper clearance between both sets of jaws when the press is neutral, consequently jaws D will have the tendency to engage jaws F, but can not engage any more than to pound until the press is tripped in a normal manner.

Under the burden of strenuous operation of punch presses it is known that both sets of jaws were subjected to such severe wear that it became actually necessary to install new jaws in both the clutch head and bull gear at regular intervals of two months during the period of such strenuous activity. It is needless to add that this was accomplished at a great cost in time and material with the ensuing delay necessary for this purpose.

The bracket C will assume the tilted position shown in Figure 2 of the drawing due to the fact that the lowermost pair of coil springs 8 will be compressedY before the upper pair of coil springs are compressed, when the cam H is actuated by the trip mechanism to release the jaws of the clutch head from engagement with the jaws of the bull gear.

Having thus described my invention, what I claim as new is: Y

1. In combination with the trip bracket of a punch press, four principal units, each of said units comprising an elongated stud, one end of said stud being adapted to `threadedly engage the frame of the press and be disposed at right angles thereto, yieldable means whereby said studs are coordinated with said bracket, for purpose of providing a clearance between the clutch head and the bull gear after their release.

2. In combination with the trip bracket of a punch press, four principal units, each of said units comprising a stud, said studs being permanently xed with the frame of the press, a sleeve for each of said studs, said sleeves threadedly engaging the outer end portions of said studs respectively, the aforesaid bracket having 50 openings for the passage of said studs respectively, and yieldable means intermediate the aforesaid sleeves and bracket for returning the latter to normal position after operation of the tripl. ping mechanism of the press.

3. In combination with the trip bracket of a punch press, four principal units, each of said units comprising a stud that is permanently xed with the frame of the press, a sleeve for each 5 threadedly engaging said sleeves respectively, said bracket having openings, said studs adapted to pass freely through said openings, a collar freely disposed upon each of said studs, said collars being adjacent the aforesaid bracket, a spring mounted upon each of aforesaid studs, said spring being intermediate the aforesaid sleeve and collar, means for adjusting the tension of said springs, said means comprising a nut threadedly engaging the outer end of each of aforesaid studs.

4. In combination with the trip bracket of a punch press, a plurality of units adapted to be coordinated with the trip bracket, each of said units comprising a stud permanently fixed with the face of the press frame, a nut, sleeve, spring and collar for each of said studs, said collars mounted upon said studs adjacent said trip bracket, said sleeves threadedly engaging the free ends of said studs, said nuts threadedly engaging the said studs and adjacent said sleeves and upon the eXtreme free ends of the studs, said springs being interposed between said sleeves and collars, the specific relation of the elements named constituting means in cooperation with the aforesaid bracket for providing clearance between the clutch head and the bull gear of the press after same has been normally operated,

5. The combination with the frame, bull gear, clutch head, including the coacting jaws associated therewith, and the trip mechanism including the movable trip bracket, of a punch press; of yieldable means associated with the frame and the trip bracket for assisting in the releaseV of the clutch head from the bull gear and maintaining said coacting jaws clear of one another when the press is idling said yieldable means including studs projecting outwardly from the frame through the movable bracket, and coil springs encircling the outer end portions of the studs and bearing against the trip support bracket.

press; of yieldable means associated with the 5 frame of studs projecting outwardly from the frame and passing freely hrough the aforesaid bracket, a member threaded on the outer end of each stud, and a coil spring encircling the projecting portion of each stud and bearing against the movable bracket, said coil spring assisting in l the release ofthe clutch head from the bull gear and maintaining clearance between the coacting jaws when the press is idling.

7. The combination with the frame, bull gear, clutch head, includingthe coacting jaws associated therewith, and the trip mechanism including the movable trip bracket, of a punch press; of yieldable means associated with the frame of studs projecting outwardly from the frame and passing freely through the aforesaid bracket, a member threaded on the outer end of each stud, a longitudinally adjustable member secured on the outer end of each stud, a collar freely disposed upon each stud adjacent the bracket, and a coil spring encircling each stud and interposed between said adjustable member and the collar for normally assisting in the release of the clutch head from the bull gear and maintaining clearance between the coacting jaws when the press is idling. Y

PERCY E. BOYD.

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