US3390877A - Magazine for sheet metal blanks - Google Patents

Description

uly 2. 1968 r B. 1. WALLIS 3,390,877

MAGAZINE FOR SHEET METAL BLANKS Filed March 11, 1966 5 Sheets- Sheet 1 o N V v? v m 8 Li 2 1 N a I: \9

INVENTOR BERNARD J.WAu.as

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MAGAZINE FOR SHEET METAL BLANKS Filed March 11', 1966 5 Shets-Sheet 2 s 8 :g 8 g co/ (\1- 3 iwf 9."- u; 2"

s; 6-K g INVENTOR.

BERNARD J. WALIJS ATTORNEY B. J. WALLIS MAGAZINE FOR SHEET METAL BLANKS July 2. 1968.

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BERNARD J. WALL\5 ATT'O RNEY United States Patent 3,390,877 MAGAZINE FOR SHEET METAL BLANKS Bernard J. Wallis, Livernois Engineering Co., 25200 Trowbridge Ave., Dearborn, Mich. 48124 Filed Mar. 11, 1966, Ser. No. 533,505 22 Claims. (Cl. 271-44) ABSTRACT OF THE DISCLOSURE A device for stripping sheet metal blanks from the bottom of a stack which includes a pair of pivotally supported, spring biased jaws adapted to engage opposite edge portions of the blanks at the lower end of the stack so as to apply a downward and inward pressure to these blanks and thereby maintain the lowermost l lanks in a substantially flat condition to facilitate stripping them from the bottom of the stack. Means are provided for pivoting the jaws upwardly out of engagement with the edges of the blanks after each blank is stripped from the bottom of the stack so as to permit the stack as a whole to shift downwardly between successive strokes of a blank stripper.

This invention relates to a magazine for retaining a plurality of sheet metal blanks in a stack and for dispensing them one at a time from the lower end of the stack.

In many punch press operations involving the stamping of sheet metal workpieces, it is necessary to feed sheet metal blanks one at a time to the press. Frequently the blanks are arranged in a stack and are fed one at a time from the stack of blanks to the press. From the practical standpoint, it is often desirable to feed the blanks from the bottom of the stack and to replenish the stack with blanks from the upper end thereof. However, when the sheet metal blanks are in the form of relatively thin stock or when the blanks are otherwise inherently flimsy because of their shape, size, etc., feeding of the blanks from the lower end of the stack presents problems.

Sheet metal blanks which have been die cut from larger pieces of stock are frequently bowed, slightly bent, or otherwise distorted. When such blanks are arranged in a stack, they normally do not assume a close packed condition; edge portions of the blanks-are spaced from the adjacent blanks and thus render it difficult to strip the lowermost blank in the stack in order to feed it to the press. In'such arrangements the blank pushing or stripping device for removing the lowermost blank in the stack demands that the blanks be in a fiat tightly-compacted condition.

One attempt to solve this problem has been the provision of a spring or other biasing means at the upper end of the magazine for applying a downward compressive force against the upper end of the stack of blanks so as to retain them in a flattened condition. This solution is not entirely satisfactory because if there are numerous blanks in the stack, the compressive force required to flatten the lowermost blanks is excessive and the friction resulting therefrom on the lowermost blank requires 'a relatively large force to withdraw such blank from the lower end of the stack. In addition, when the compressive force is applied to the upper end of the stack, it becomes necessary to remove the device for applying such force when it is desired to add to the supply of blanks in the stack from above.

The present invention has for its primary object the provision of a magazine for sheet metal blanks which eliminates the problems described above.

More specifically, it is an object of the present invention to provide a magazine of the type described wherein the blanks adjacent the lower end of the stack are main- 'ice tained in a flat compacted condition by applying inwardly and downwardly directed forces to the periphery of the stack of blanks adjacent its lower end.

The means for applying the downwardly and inwardly directed forces to the periphery of the stack adjacent its lower end are preferably in the form of pivotally supported jaws which are shaped to engage the edges of the blanks adjacent the lower end of the stack and which are spring biased to apply a downward and inward force to the edges of said blanks. More specifically, each jaw is in the form of a pivotally supported block which carries a slidable jaw element. The blocks themselves are biased to rotate in a direction downwardly and toward the stack of blanks, and the jaw elements are biased in a downwardly and inwardly inclined direction. This arrangement assures an effective gripping of the jaws with the blanks at the lower end of the stack and a uniform downward pressure on such blanks so that they remain flat and are readily stripped from the lower end of the stack by the blank pusher. Means are provided for intermittently moving the jaws out of engagement with the periphery of the stack in response to reciprocation of the blank pusher so that the blanks will gravitate progressively downwardly in the stack.

In the drawings:

FIGURE 1 is a top plan view of a magazine constructed in accordance with the present invention.

FIGURE 2 is a side elevational view, partly broken away and with the upper portion of the magazine shown in section taken generally along the line 22 in FIG. 1.

FIGURE 3 is an end View of the magazine.

FIGURE 4 is a sectional view taken along the line 44 in FIG. 2.

FIGURE 5 is a sectional view along the line 55 in FIG. 1.

FIGURE 6 is a sectional view along the line 6-6 in FIG. 1 and showing the blank pusher in the advanced position wherein the lowermost blank has been stripped from the stack.

FIGURE 7 is a view similar to FIG. 6 showing the blank pusher in the retracted position, that is, in the position just prior to stripping a blank from the bottom of the stack.

FIGURE 8 is a fragmentary view on an enlarged scale showing one of the spring biased jaws in the position it assumes when the parts are in the relation illustrated in FIG. 7.

FIGURE 9 is a view similar to FIG. 8 and showing the jaws in the position it assumes when the parts are in the relation shown in FIG. 6.

FIGURE 10 is a fragmentary top view of the two slide plates on which the stack of blanks is supported.

Referring first to FIGS. 1 and 2, the magazine of the present invention includes a base 10 comprising a base plate 12 with a pair of upstanding side walls 14 to the inside faces of which are fixedly secured hinge blocks 16. A support plate 18 spans and is rigidly mounted on the upper ends of side walls 14. The magazine also includes a head 20 comprising a pair of side plates 22 fixedly interconnected at each end by end plates 24 and pivotally supported on hinge blocks 16 by means of pins 26. On the inner faces of each side wall 22 there is mounted in the central portion thereof a guide block 28 which, in the case of blanks having a circular periphery, are fashioned with curved inner faces as shown. On each guide block 28 there are mounted two upright guide rods 30 which cooperate to form a vertical guideway for a stack of blanks. A rear jaw 32 is fixedly mounted on one end wall 24 by gussets 34 and front jaw 36 is mounted on the front wall 22 by similar gussets 34 (FIGS. 3 and 6). laws 32 and 36 have their inner opposed ends arcuately shaped to form arcuate segments of the circle defined by the inner curved surfaces of guide blocks 28. Within the head section 20 there is also pivotally supported as by pins 40 a pair of rocking jaw assemblies 42.

Referring now to FIGS. 3 and 4, a pair of parallel, laterally spaced gib plates 44 are fixedly mounted on support plate 18 of base 10. The overhanging edges of gib plates 44 overlie the opposite longitudinal edges of a bearing plate 46. Bearing plate 46 is slidably supported on a pair of wear plates 48 fixedly secured on support plate 18. Bearing plate 46 is secured as by screws 50 (FIG. 1) to the underside of the horizontally extending slide portion 52 of a draw bar 54. The vertically extending portion 56 of draw bar 54 has a rod 58 connected thereto. Rod 58 is adapted to be reciprocated by a mechanism, not illustrated. In order to permit horizontal reciprocation of the vertically extending portion 56 of draw bar 54, support plate 18 is fashioned with a central longitudinally extending slot 60 (FIG. 1).

On the top side of the horizontal slide portion 52 of draw bar 54 there are supported two adjacently positioned and abutting slide plates, a forward plate 62 and a rear plate 64. Rear plate 64 has a thickness which exceeds the thickness of forward plate 62 by approximately the thickness of one of the blanks adapted to be stacked in the magazine. The abutting ends of slide plates 62, 64 are arcuately shaped as indicated at 66 in FIG. 10 and the step between these two plates is defined by a carbide insert 68 which has its forward edge correspondingly curved to conform with the periphery of the blanks stacked in the magazine. As mentioned previously, in the particular arrangement illustrated, the magazine is designed to accomodate blanks of circular configuration.

There is also mounted on the horizontal slide portion 52 of draw bar 54 a lifter cam 70 having a downwardly offset central portion 72 secured within a notch 74 (FIG. 1) on the underside of slide portion 52 by a screw 76. Lifter cam 70 also includes a pair of cars 78 ofliset upwardly and extending laterally from the central portion 72 in opposite directions and terminating adjacent the inner faces of the side walls 22 of head section 20 (FIG. 4).

Referring now to FIGS. 2, and 8, each jaw assembly 42 comprises a U-shaped block 80 closed at its upper end by acap 82. Each block 80 is centrally apertured through the bight portion thereto to form a bore 84 which receives a sliding jaw 86 having a jaw plate 88 fixed to the lower end thereof. The inner opposed edges of the two jaw plates 88 are provided with arcuately shaped carbide inserts 90. The upper end of each sliding jaw is fashioned with a flange 92 which serves as a stop to limit downward movement of each jaw 86 in response to the biasing effect of a compression spring 94. Each block 80 is biased by a pair of springs 96 to rotate about the pivot pins 40 such that the carbide inserts 90 are urged in a direction inwardly and downwardly. Thus, as illustrated in FIG. 2, the forward jaw assembly 42 is biased by springs 96 to rotate in a clockwise direction; and the rear jaw assembly 42 is biased to rotate about its pivot pin 40 in a counterclockwise direction.

Fixed jaws 32, 36 are provided on the lower side thereof with jaw plates 98 at inner opposed edges of which are secured arcuately shaped carbide inserts 100. The carbide inserts 90 on jaw plates 88 are generally vertically aligned with the carbide inserts 100 on jaw plates 32, 36. Jaw plates 98 have their lower faces disposed in a plane slightly above the top face of the rear slide plate 64 (FIG. 9).

On each side of the forward pivoted jaw assembly 42 there is mounted an arm 102 which extends down below jaw plates 88. Referring to FIGS. 6 and 7, each arm 102 is fashioned with a head 104 at the lower end thereof, head 104 having a rounded upper end 106 and a detent 108 at its lower end. The detents 108 normally rest upon the top faces of gib plates 44. Adjacent each detent 108 head 104 is formed with a horizontally extending edge 110 and an upwardly and outwardly inclined cam edge 112. The rear pivoted jaw assembly 42 is also provided with an arm 114 on the opposite side faces thereof. Each arm 114 has a generally horizontal inwardly projecting extension 116 which overlies head 104 of the opposite arm 102 and rests upon the rounded upper end 106 thereof.

As is illustrated in FIGS. 6 and 7, when draw bar 54 is retracted from its advanced position, illustrated in FIG. 6, the laterally extending ears 78 on the lifter cam 70 engage the inclined cam edges 112 on the two arms 102 as the draw bar approaches the end of its retraction stroke to elevate the head 104 of arms 102. Since the inward extension 116 on arms 114 rest upon the heads 104, when the ears 78 engage the inclined edges 112 of arms 102, the forward jaw assembly 42 is pivoted in a counter-clockwise direction against the bias of springs 96 and the rear jaw assembly 42 is pivoted clockwise against the bias of springs 96. Thus, since the jaw plates 88 at the lower ends of the sliding jaws 86 are disposed in a plane above the pivot pins 40, the inserts 90 at the inner edges of jaw plates 88 are caused to rock in a direction upwardly and away from one another.

In operation, a plurality of blanks are deposited in the form of a stack 118 within the vertical guideway formed by guide rods and guide blocks 28. With draw bar 54 in the advanced position shown in FIGS. 2, 6 and 9 the lowermost blank 120 in stack 118 rests upon the top supporting face of slide plate 64 as shown in FIG. 9. In this condition of the magazine, the ears 78 of lifter cam 70 are disposed in the position illustrated in FIGS. 2 and 6. Thus springs 96 are bias the front and rear jaw assemblies 42 to the positions shown in FIGS. 2 and \6, wherein the detents 108 engage the top faces of gibs 44 and the inner ends 116 of arms 114 rest upon the curved upper ends 106 of heads 104. Jaw plates 88 at the lower ends of slidin jaws 86 are dimensioned such that in the position of the jaw assemblies shown in FIGS. 2 and 6 the carbide inserts engage the peripheral edges of the blanks in stack 118 above the lower end of the stack. It will be appreciated with the jaw plates 88 engaging the stack 118 of blanks as shown in FIG. 9, the peripheral flange 92 at the upper end of each sliding jaw 86 is spaced slightly above the stop face 122 at the bight portions of blocks 80. Springs 94 in each jaw assembly thus urge the sliding jaws in a direction downwardly and inwardly toward each other such that the inserts 90 exert an inwardly and down wardly directed force against the lower blanks in the stack 118, the resultant of this force being designated by the arrow 124 in FIG. 9. Since the jaw plates 88 are acting only upon the blanks at the lower end of stack 118, it will be appreciated that the amount of force necessary to maintain the blanks below jaw plates 88 in a flat, tightly-compacted condition is substantially less than the force that would be required to maintain these blanks in a flat, tightly-compacted condition if the force were applied to the upper end of the stack 118 rather than adjacent the bottom of the stack.

Thereafter when draw bar 54 is retracted from the position shown in FIG. 6 to that shown in FIG. 7, the two slide plates 62, 64 are shifted to the right; and as the draw bar approaches the end of its retraction strokes, the cars 78 of lifter cam 70 engage the inclined cam edges 11.2 on the heads 104 of arms 102 to pivot to the two jaw assemblies 42 upwardly and away from one another. When the jaws are so pivoted, the peripheral flanges 92 on the sliding jaws 86 bottom against the stop surface 122 on blocks 80, and the carbide inserts 90 swin-g upwardly and outwardly out of engagement with the peripheral edges of the blanks in the stack.

When draw bar 54 is in the fully retracted position shown in FIG. 7, the step between the two sliding plates 62, 64, defined by the carbide insert 68, has been displaced beyond the insert in the fixed rear jaw 32. Thus since the spring :biased jaws are out of engagement with the edges of blanks in the stack (FIG. 8), the blanks are free to gravitate downwardly so that the lowermost blank 120 is now restin on the top face of the forward slide plate 62. The blanks at this time may be in a loosely-compacted condition in the stack. However, when draw bar 54 is thereafter advanced, the initial movement thereof causes the ears 78 on litter cam 70 to move out of engagement with the heads 104 of arms 102. This occurs before the insert 68 engages the edge of the lowermost blank resting on slide plate 62 or at least before insert 68 advances .past the insert 100 on rear jaw 32. When the cam ears 78 move out of engagement with arms 102, springs 96 rock the two jaw assemblies 42 downwardly and inwardly. However, before detents 108 engage the top faces of gib plats 44, inserts 90 on jaw plates 88 engage the periphery of the stack of discs. Thus continued pivotal movement of jaw assemblies 42 under the bias of springs 96 (which are stronger than springs 94) compresses springs 94 and results in the application of a downwardly and radially inwardly directed force against the edges of the blanks at the lower end of the stack 118. In this connection it is important to note that the inward rocking action of jaw assemblies 42 contribute substantially to the application of a downward force to the blanks at the lower end of the stack. It is also important to note that since the two jaw assemblies 42 act upon the blanks at diametrically opposite edge portions which are aligned with the direction of travel of draw bar 54, these two edge portions of the blanks at the lower end of the stack will be flattened and vertically compressed even though the balnks may be slightly bowed in the direction of draw bar travel.

Upon continued advance of draw bar 54 insert 68 at the leading edge of slide plate 64 engages the lowermost blank resting on the top side of slide plate 62 and strips this blank 120 from the bottom of the stack and advances it with the draw bar. Inthe fully advanced position of draw bar 54 shown in FIG. 9, the stripped blank 120 on the top face of slide plate 62 underlies fixed jaw 36. Suitable friction means such as spring detents or the like (not illustrated) may be provided on the under side of jaw 36 to prevent the stripped blank 120 from being retracted with draw bar 54. Then as previously described, when draw bar 54 is again retracted jaw plates *88 are pivoted out of engagment with the stack of discs as the draw bar approaches its fully retracted position and the blanks are permitted to shift downwardly in the stack.

Thus it will be seen thatthe magazine construction herein described effectively eliminates the problems encountered when a stack of blanks in a magazine are subjected to a compressive force from the upper end of the stack. Since the two jaw plates 88 exert pressure against the edges of the blanks only at the lower end of the stack, the force required to maintain the blanks at the bottom of the stack in a flat, tightly-compacted condition is relatively slight as compared with the force that would be required if it were applied to the top of the stack. Since the upper end of the stack is unobstructed, additional blanks can be deposited on the stack while the magazine is in operation. As pointed out above, another desirable feature of the magazine herein described resides in the application of a flattening force to edge portions of the discs in the stack which are in line with the direction of travel of the draw bar. This is especially important in the case of discs formed of relatively thin flimsy stock which would have a tendency to bow byv reason of the force applied to the edges thereof by the jaw plates 88 themselves. With the above described arrangement, if there is a tendency for the blanks to bow slightly, it will not interfere with the ability of the insert 68 at the leading edge of slide plate 64 to strip the lowermost blank 120 from the bottom of the stack.

I claim:

1. A magazine for dispensing sheet metal blanks one at a time from a stack of such blanks comprising a support, guide means on said support for retaining a plurality of. blanks in a stack, a movable blank pusher adjacent the lower end of, the guide means arranged when actuated to strip the lowermost blank in the stack laterally out of the stack, means positioned to engage the peripheral edges only of blanks adjacent the lower end of the stack 'for applying only a downward and radially inwardly directed force to the blanks adjacent the lower end of the stack to maintain said lower blanks in a generally fiat, compacted condition and means for releasing said force applying means after each blank is stripped from the lower end of the stack.

2. The combination called for in claim 1 wherein said blank pusher comprises a slide on said support shiftable in a direction transversely of the axis of the guide means, said slide being provided with a vertical step therein having a height substantially no greater than the thickness of one of the blanks in the stack, said step dividing said slide into two blank supporting portions of different heights, one of said supporting portionssunderlying the lower end of the stack in one position ofthe slide and the other supporting portion underlying the lower end of the stack in another position of the slide, said step being adapted to engage the edge of the lowermost blank supported on the lower portion of the slide and displace it laterally in the direction of slide movement when the slide is actuated.

3. The combination called for in claim 1 wherein said force applying means comprises a pair of generally opposed, movably supported jaw'assemblies and means for biasing'said jaw assemblies to move in a direction inwardly and downwardly toward the bottom of the stack in said guide means.

4. The combination called for in claim 3 wherein said jaw assemblies are arranged to engage generally diametrically opposite edge portions of one or more blanks in the stack spaced intermediate the upper and lower ends of thestack.

5. The combination called for in claim 3 wherein said jaw assemblies are pivotally supported.

' 6. The combination called for in claim 3 including means for moving said jaw assemblies in a direction upwardly and outwardly away from the lower end of the stack of blanks during a portion of the movement of the blank pusher to thereby release the blanks in the stack from said jaw assemblies.

7. The combination called for in claim 3 wherein each jaw assembly comprises a movably supported member and a jaw member movably mounted on said movably supported member, said biasing means comprising a first spring means biasing the first movably supported member a direction inwardly toward the stack of blanks in the guide means and a second spring means biasing said jaw member downwardly on the movably supported member, said jaw member being shaped to engage the periphery of the blanks in the stack.

8. The combination called for in claim 7 wherein said first member is pivotally supported and said jaw member is slidably supported on said pivotally supported member.

9. The combination called for in claim 7 wherein said jaw member is supported on said pivotally supported member for movement in a direction downwardly and inwardly of the stack of blanks in said guide means.

10. The combination called for in claim 9 wherein said jaw member is slidably supported on said pivotally supported member.

11. The combination called for in claim 7 wherein the first spring means have a greater biasing effect than the second spring means.

12. The combination called for in claim 7 wherein, said blank pusher is adapted to reciprocate in a rectilinear path and said pivotally supported member is arranged for pivotal movement about an axis extending transversely of the direction of reciprocation of the blank pusher.

13. The combination called for in claim 3 wherein each jaw assembly comprises a pair of movably interengaged members, said biasing means comprising a first spring means biasing one of said members generally inwardly toward the blanks in the guide means and a second spring means biasing the other member generally downwardly toward the lower end of the stack of blanks in the guide means, one of said members having a jaw portion adapted to engage the peripheral edge of the blanks.

14. The combination called for in claim 3 wherein said guide means includes means forming a pair of generally oppositely disposed, fixed jaws located above said blank pusher and adapted to prevent lateral displacement of the second lowermost blank in the stack when the lowermost blank is stripped from the bottom of the stack by the blank pusher.

15. The combination called for in claim 14 wherein said jaw assemblies are disposed above said fixed jaws.

16. The combination called for in claim 2 wherein said blank pusher is adapted to be reciprocated between advanced and retracted positions, the higher portion of the slide being located to support the stack of blanks when the slide is in the advanced position and the lower portion of the slide being adapted to support the stack of blanks when the slide is in the retracted position, said step on said slide being adapted to strip the lowermost blank from the stack when the slide is shifted from the retracted to the advanced position.

17. The combination called for in claim 16 wherein said means for releasing said force applying means from engagement with the blanks in the stack are actuated as the slide approaches the end of its retraction stroke.

18. The combination called for in claim 17 including means for re-engaging said force applying means when the slide begins to move in the advance direction from the retracted position and prior to engagement of said step with the edge of the lowermost blank.

19. In a magazine of the type wherein a plurality of blanks are adapted to be supported as a stack and means are provided for stripping the blanks one at a time from the bottom of the stack, that improvement which comprises means positioned above the lower end of the stack and adapted to engage generally opposite peripheral edge portions of one or more blanks which are disposed intermediate the upper and lower ends of the stack, said blank engaging means being movable in a direction inwardly and downwardly toward the lower end of the stack, means biasing said blank engaging means in said direction to maintain said intermediate blanks and the blanks therebelow in a fiat compacted condition and means for releasing said blank engaging means from engagement with the stack after each blank is stripped from the bottom of the stack.

20. The combination called for in claim 19 wherein said blank engaging means comprises a pair of movably interengaged members, said biasing means comprising a first spring means biasing one of said members generally inwardly toward the blanks in the stack and a second spring means biasing the other member generally downwardly toward the lower end of the stack.

21. The combination called for in claim 19 wherein said blank engaging means comprises a pair of generally diametrically opposite jaw assemblies, each jaw assembly comprising a pivotally supported member adapted to rotate in a direction inwardly of and toward the lower end of the stack of blanks and a jaw member arranged for sliding movement on the pivotally supported member at an angle inclined inwardly of and toward the lower end of the stack, said sliding jaw member having a blank engaging portion, said biasing means comprising a first spring means biasing said pivotally supported member and a second spring means biasing said sliding jaw in said respective directions.

22. The combination called for in claim 21 wherein said first spring means have a greater biasing effect than the second spring means.

RICHARD E. AEGERTER, Primary Examiner.

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