US1991457A - Press for cutting metal and other sheets - Google Patents

Description

Feb. 19, 1935. GRIFFITHS 991,457

PRESS FOR CUTTING METAL AND OTHER SHEETS Filed Oct. 27, 1954 s sheets-sheet 1 Feb. 19, 1935. H., A. GRIFFITHS PRESS FOR CUTTING METAL AND OTHER SHEETS Filed Oct. 27, 1934 5 Sheets-Sheet 2 5 Sheets-Sheet 5 H. A. GRIFFITHS PRESS FOR CUTTING METAL AND OTHER SHEETS Filed'Ocfi. 27, 1954 an& Ha a W T w Feb. 19, 1935.

Patented Feb. 19, 1935 7' UNITED STAT E.

PaEss FOR CUTTING METALANID OTHER SHEETS Harry Albert Griffiths, Edgbaston, Birmingham, England Application October 2'7,

1934; SerialNo. 750,377

In Great Britain September 8, 1933 V 11 Claims.

This invention has for its object to provide an improved pressicr use in the cutting or" circular or other blanks from metal or .other sheets.

Theinvention comprises the combination with 5 an, inclined guide and a work holder slidable on the guide, of means for imparting intermittent upward movements to the .slide along the guide, and means for effecting intermittent downward movements of the slide along the guide under the action of gravity. g

Also the invention comprises thecombination with the said inclined guide, of means for ima parting to it intermittent lateralmovements as hereinafter described. I

In the three accompanying-sheets of explanatory drawings:

Figure 1 is a sectional side elevation and 'Figure 2 a plan illustrating" a mechanism constructed in accordancewith this invention.

Figure 3 is a front elevation showingthe' hori zontal guide and associated parts, whilst Figure 4 is a side elevation of the inclined guide and associated parts.

In carrying theinvention into effect in the manner illustrateda fixed horizontal guide bar a is arranged on the main frame I) of-the machine at thefront or one side'of the cutting tools. These latterare not shown but they are of the usual form consisting of a punch and 'die, and their axis is arranged at an angle of about 30 to the vertical. On the guide a is arranged a slide carrying an inclined bed (1, the plane of movement of this bedv being at right angles to the axis of the tools; On the inclined bed is mounted 5 a guide bar e which carries a slide 7 serving as the sheet holder, the sheets to be out being held by any convenient form of grippers indicated in Figure 2 by g. The slide 1 is moved upwardly on the inclined guide 6 by mechanical means to be hereinafter described, and the downward movement is effected by gravity. The slide 0 and bed d in addition tobeing carried on the guide bar a are also supported by fixed guide bars thebedd.

I On the slide 0 there is arranged a notched rack g' which is engaged by a pivoted locking pawl lo carried by a fixed bracketl on the bed of the 0 machine. The pitch of the rack notches is equal to the spacing of the rows of blanks to'be cut from the sheet,an d the engagement of the pawl with any of the notches serves-to hold the slide 0 and bed don the guides a and h'while a row 55. ofblanks is beingcut from the sheet. After, a

employedfor reciprocatingthe movable rack p."

h with which engage rollers 12 mounted beneath row of blanks-has been cut and prior to the] cutting of'the next row, the slide is moved along the guides, and is then 'heldfby the re-engagement of the pawl with another notch..

The intermittent movements'of'the slid 5 the horizontalguidesj a and 71. towards the tools afterthe completion of each row. is effected by suitable means as hereinafter described. The" return movement of the slide is'efiected by a 4 weight m after disengagement of the locking pawl 10 is. The weight also serves to hold one side of each rack. notch in turn firmly in "contact with the pawl. 70 for accurately locatingthe sheetrelatively to the tools. t I

On the guide e carriedbyqtheinclined bed d" are arranged two fixed racks/n, 0', anda recipro eatery rack p. Each of thesev is enga'ged'by a pawl] q, r, s, respectively on the slide'jsj Any convenj ient means suchas are hereafter described are 20.

In its upward movements-the rack 10 carries the slide 1 and sheet from one position to thenext .in the operation of cutting out arow of blanks.

During the return movements of the; rack the slide is, held by the pawl q engagingthefiiied rack. n,f the pawl being held firmly against fa notch in the rack by the action of gravity'lon the: slide during the cutting operation. After the slide has reached the upper limit. of its moven1ent,.the guide 0 with bed dare movedito the next position on the horizontal slidesv a, h, and the twopawls r and ,q engaging the reciprocatory rack 10 and thefixed rack n'respectively areput out 01" action. The inclined: slide now returns step by step under thev action'of gravity to itsv lower limit-of movement/for the cutting out of the next {row of b1anks.' j This movement is controlled by the third. pawl s which 'en'gages'" the other. 'fi ied rack o, the pawlbeingfmo-f mentarilyandsuccessivelyl raised outof engagee ment with any one of the notchesin'the rack] and allowed immediately afterwards to ..engag'e' the next not'chf Further details" of this device are described below; After all the blanks have been cutout from the sheet, the horizontal slide cand bed d' are; movedby theweight mabove-mentionedto their, initial position in readiness. for action on'the, next sheet. After the cutting operations the scrapportion of ,the sheet falls away bygravity or, is ejected at the back of 'thepress, ,7

Reverting to the means for actuating the slide H 1, this slide as already: mentioned receives its intermittent movements up the bedd from the reciprocatory rack p. This rack as shown in Figures 1 and 2 is supported at its upper end by a bearing t on the bed (2!. At its lower end it is secured adjustably to a bar a slidable on bearings at the underside of the bed [2. This bar a is formed with a projection 71 which engages and can slide along a grooved channel w carried on a pair of slides :1: which are reciprocated continuously by cranks y through links 2, the cranks receiving their motion from any convenient part of the driving mechanism of the press and being coordinated with the movements of the tools. By the reciprocation of the rack 10 which is correlated with the action of the cutting tools, the slide 1 together with the sheet to be acted on by the tools are carried upwards along the bed at with a step-by-step motion. In each interval of rest a blank is cut from the sheet, and return movement of the slide is prevented by, the engagement of the pawl q with the fixed rack n. When the slide 1 reaches the upper end of its travel the pawls q and r are put out of action. This is efi'ected by a lever 2 on one side of the slide which can engage a tappet'3 on the bed (1. While moving relatively to the tappet the lever is rocked and thereby caused to actuate through a link 4 a pair of cams 5 which lift the pawls against the action of springs 6. The slide f is now free, but return motion is prevented by the engagement of the pawl s with the rack 0. When it is desired to cut out the blanks in certain rows in staggered relation to the blanks in the pre ceding row the notches in the rack o are so arranged that after the pawls r, q, have been released the slide 7 is allowed to fall back immediately through a distance equal to one half of the pitch of the blank and is arrested at the end of this movement. by the engagement of the pawl s with the first notch in the rack 0. To effect the intermittent return of the slide 1 along the bed d under the action of gravity, the pawl s is intermittently released. This is effected by. a bar '7 (Figures 1, 2 and 4) carried at its ends by levers 8 to which is attached another bar 9. The latter is moved longitudinally by a lever 10, a lever 11 and a striking bar 12 attached to the front of the channel w. During the movement'of thebar 12 in the direction of the arrow (Figure 4) the lever 11 moves the lever 10 and bar 9 in the direction for lifting the bar 7 and so raising the pawl s away from the rack. The slide f can move by gravity along the bed d until it is arrested by're-engagement of the pawl s with the next notch in the rack. Meanwhile the lifting bar 7 and its operating means have returned to their initial position, or they are returned by the pressure of the pawl s under the action of the spring 13 acting on the pawl. During the return motion of the bar 12 it again strikes the lever 11, but this action isjinefiective owing to .the provision of a pin and slot or other lost motion connection'between the levers 10 and 11. A blank is out from the sheet during each interval of rest.

It will be understood that the mechanism associated with the rack o is working continuously owing to its permanent connection with the levers y, but the said mechanism is only efiective during the descending movement of the slide f on the bed (1, as during the upward movement the slide is controlled by the pawls q and 1'.

When the slide f reaches its lower position, it is arrested by a stop 14, but immediately prior to reaching the stop the lever 2 is engaged by another tappet 15 causing the lever 2 to be rocked in the opposite direction to that above described and the pawls q and r to be again brought into action. The slide now recominences its upward movement and at the same instant the bed d is given another movement on the guides a, h, and the above described cycle of operations is repeated.

As regards the means for moving the slide 0 and bed (2 on the guides a, h, this is shown in Figures 1, 2 and.3. Along one side of the slide 0 (of which only a small piece is shown in Figure 3 to avoid confusion with other parts required to be illustrated in that view), there is secured a rack 7' as already mentioned, and this is engaged by a locking pawl k. Parallel with the rack is mounted on the bed of the machine a reciprocatory bar 16 on which is pivoted a pawl 17 adapted to engage any one of a number of notches in the rack 7'. The bar 16 is continuously reciprocated by a bell crank 18 acting through a link '19, the crank 18 receiving its motion from any convenient part of the driving mechanism of the press. Alongside and between the rack 9' and bar 16 is arranged a bar 20 the purpose of whichis to control the pawl 1'7. The bar 20 as shown in Figure 3 is carried at itsends by levers whe eby longitudinal movement of the bar is accompanied by an upward and downward movement. The said bar 29 is reciprocated only when the slide J reaches either the top or the bottom of its travel, and the motion of the bar is derived from a suitably timed cam or other means actuated by the driving mechanismv of the press and coordinated with the travel of the slide 7. As shown in Figure 3 the pawl 17 is out of action. When the bar 20 is moved to the right it allows the pawl to drop into engagement with the rack 7' and movement is through the pawl when the -bar 16 moves'towards the left. The locking pawl is does not'interfere with this movement as the notches in the rack bar 1/ are each formed at one side with an inclined edge. When the bar 16 is moving towards the right, the rack 7' is held by the pawl k and is pulled tightly against one side of that pawl by the wei ht m. At the same time the bar 20 returns towards the left and raises the pawl 17 out of action so that further movement cannot be given to the bed (1 until the slide f reaches the other limit of its travel.

When the bed cZ reaches the end of its travel.

along the guides at, in the manner above described, and the scrap portion of the sheet has been removed, the bed is returned to its initial position prior to the insertion of another sheet. The return movement of the bed is effected by the weight m after the release of the locking pawl k. This release is efiiected in the following manner. The pawl k at the side opposite that which engages the rack is acted on by a bar 22 which is attached to the pawl (Figure 1). This bar is urged in the upward direction for engaging the pawl with the rack by a spring 23. The bar is moved in the opposite direction for releasing the' pawl by a bell crank lever 24 (Figure 3) which is actuated momentarily by a rod 25 connected to a cam or other means driven by the mechanism of. the press and suitably co-ordinated withthe movement of the bed it. After the bar 22 has been moved in the downward direction it is held by a spring controlled catch lever 26 pivoted on the bracket Z and arranged to swing over the top or" the bar. The-latter cannot now move again until the bed under the action of the Weight m has reached its initial position, or nearly so, when the tappet 27 on the then given to the rack thereby absorbed. I

bed strikes -the catch and withdraws-it from en-;

to. its activeposition in readinessfor repetition of the movements above described.

' To minimize shock-when the bed reaches its initial position, there is mounted on the bed a buffer piece 28 acted on by a strong spring29 and arranged. to engage an inclined surface 30 on'the stop collar carried by the bar a. While the buffer is moving along that surfacethe spring is compressed and the momentum of the bed is To enable the machine to be readily adapted for cutting out blanks of difierent sizes, involving different spacings of the rows in the sheet, all

the racks are made readily removable so that suitable racks can easily be mounted in the machine, and the lockingpawl k: is mounted adjustably on the bed of the machine, }the bracketl being movable on its support by a screw 32.

It sometimes is required to be able to lower the slide I along the bed d while the pawls q, r, are out of action, as for example when setting up the machine, and to enable this to be done there is combined with the pawl s a handlever 33 acting through a link 34 on a cam 35. By movement of the hand lever the pawl can be lifted out of action and the slide is then free. I

By this invention I 'am able to simplify greatly the design and construction of machines of the kind to which the invention relates, to accelerate the normal rate of working and also to obviate obstruction to free movement of the blanks and the scrap away from the machine. I

Having thus described my invention what I claim as new and desire to secure by Letters Patent is: V 1. In presses for cutting metal and other sheets, the combination of a longitudinally inclined guide, a work holder slidable along the guide, a pair of fixed racks and a reciprocatory rack carried and arranged longitudinally on the guide, pawls on the work holder for engaging the racks, meansassociated with one of the fixed racks for intermittently raising out of action the pawl engaging that rack, and means for putting the other two pawls out of action throughoutthe downward travel of the work holder, the arrangement of the parts being such that engagement of the two latter pawls with their racksserves to effect and control the movement of the work holder in the upward direction on the guide, whilst .the return motion is effected by gravity under the control of the other rack and pawl, substantially as described.

2. The combination with mechanism as claimed in claim 1, of means for raising out of action the two pawls which are operative during the upward movement of the work holder when the latter reaches the upper end of its travel and for reengaging the pawls with the racks when the work holder reaches the lower end of its travel, subfor raising said pawls out of action against the springs, and tappets on the slide for automatically actuating the said device at each end of the travel of the work holder, substantially as bar, the rising movements being utilized for lifting the operating pawl out of action, and the falling movements allowing the operating pawl'to described. I 4. In mechanism, as claimed in claim 1, operating means for the reciprocatory rack, comprising an Ioscillatorv lever, a slide actuated by thez said lever, a channel member arrangedtranse;

versely' to the direction of motion; of the said slide, and another slide arranged parallel with the firstslide and actuated by engagement; with, f the'said. channel membe1-,,the vsecond slide be- I rack, substantially ashdeing connected tothe scribed.

5. The; combination with the mechanism claimed in claim 1, of a pawl controlling bar situated alongside the rack associated with the gravity movements of the work holder, a spring for holding the corresponding pawl in engagement with the last mentioned rack, and means for im parting longitudinal and rising: and falling move-@ ments to the said bar, the bar by its rising move; ment being adapted to raise the pawl out of action against the force of said'spring, substantially as described.

6. In mechanism as claimed in claim 1,;the combination with the rack associated with the gravity movementsof the work holder and the pawl engaging that rack, of a longitudinally ar ranged pawl controlling bar, levers carrying said 7 bar, a lever device for imparting rising and falling as well as longitudinal movements to the said bar through the said levers, and a reciprocatory member for actuating the said lever device, the'latter being such that movement of the reciprocatory member in one direction only is ,utilized to operate the device, substantially as described.

7. In mechanism as claimed in claim 1, the combination with the rack associated with the gravity movements of the work holder and the pawl engaging that rack, of a pawl controlling bar, levers carrying the bar adapted to impart thereto rising and falling as well as longitudinal movements, a lever device for actuating the bar throughthe said levers, a reciprocatory member member in one direction only is utilized to operate the device, and hand operated means for.

putting'the pawl out of action, substantially as described.

8. In presses for cutting metal and other sheets, the combination with mechanism as claimed in claim 1, of means for imparting intermittent lateral movements to the inclined guide, sub-,

stantially as described.

9. In mechanism as claimed in claim 1, the combination of a fixed horizontal guide, a rack mounted on the inclined guide, a locking pawl engaging the rack, a reciprocatory bar, an operat- .4 for actuating the said lever device, the latter being such that movement of the reciprocatory.

said guide to its initial position after the move ments under the action of the operating pawl have been completed, substantially as described.

10. In mechanism as claimed in claim 1, the combination of a fixed horizontal guide, a rack mounted on the inclined guide, a locking pawl' engaging the rack,a reciprocatory'bar, an operating pawl carried by the bar and adapted to engage the rack, a bar for controlling the latter 3 pawl, and means for imparting longitudinal and. rising and falling movements to the controlling scribed.

11. In mechanism as claimed in claim 1, the

combination of a fixed horizontal guide, the in-' clined guide being slidable on the horizontal guide, a rack mounted on the inclined guide, a

1,991,457" be eng'aged' with the rack, substantially as dieing the pawl from the rack, a spring for moving the bar in the opposite direction, a spring controlled catch for securing the bar with the pawl out of action, means co-ordinated with the movements of the inclined slide for actuating the said lever, and a tappet on the slide for releasing the catch when the slide is returned to its initial position, substantially as described.

HARRY ALBERT GRIFFITHS.

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