US3488987A

US3488987A - Method and apparatus for producing smooth-edge blanked sheet metal parts

Info

Publication number: US3488987A
Application number: US688930A
Authority: US
Inventors: Oscar W Stoeckli
Original assignee: OSCAR W STOECKLI
Current assignee: OSCAR W STOECKLI
Priority date: 1967-12-07
Filing date: 1967-12-07
Publication date: 1970-01-13
Anticipated expiration: 1987-01-13
Also published as: SE351574B; DE1811649A1

Description

Jan. 13, 1970 o. W. STOECKLI METHOD AND APPARATUS FOR PRODUCING SMOOTH-EDGE BLANKED SHEET METAL PARTS 7. 1967 3 Sheets-Sheet l Filed Deo.

Jan. 13, 1970 O. W. STOECKLI METHOD AND APPARATUS FOR PRODUCING SMOOTH-EDGE BLANKED SHEET METAL PARTS Filed Dec. 7, 1967 5 Sheets-Sheet 2 'Le i x 14 ,lo 8l l 48 8 1 "lo l, e l o a4 "ig be 9a O @5 1g m O 58 sa "-25 BB' i O di l 10j nl O se @um mf@ 80 a@ I4 f A H' 2 l ma *n 4 ,i E

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METHOD AND APPARATUS FOR PRODUCING SMOOTH BLANKED SHEET METAL PARTS Filed Dec. 5 Sheets-Sheet 3 MN5/v70?, 0504,@ /14 570504/ BY @MMC/ww United States Patent O 3,488,987 METHOD AND APPARATUS FOR PRODUCING SMOOTH-EDGE BLANKED SHEET METAL PARTS Oscar W. Stoeckli, 130 Theodore Fremd Ave., Rye, N.Y. 10580 Filed Dec. 7, 1967, Ser. No. 688,930 Int. Cl. B21d 31/02 U.S. Cl. 72-329 ABSTRACT OF THE DISCLOSURE A method and means for forming sheet metal parts by a machine which includes compound dies. As the machine operates, its stroke moves a punch and die relatively toward one another to blank the outside contour of the sheet metal parts. A further punch and die thereafter shaves the outer edges of the blanked part to provide a smooth edge surface. The blanking and shaving are performed during a single stroke of the machine, and, if it is desired to have internal holes in the part, a piercing operation can also be performed during such single stroke.

This invention relates to the fabrication of parts formed from sheet metal or the like and more particularly it relates to a method and apparatus wherein the parts are blanked to the desired configuration, and thereafter, the edges of the blanked parts are shaved to provide a smooth outer edge which is free from burrs.

There are many well known forms of blanking devices for producing sheet metal parts and one satisfactory form of such apparatus is shown in my prior U.S. Patent No. 3,216,299, issued Nov. 9, 1965. In general, all such prior devices, including the one shown in my aforementioned patent, utilize punch and die arrangements for forming a particularly shaped part out of a larger piece of metal. Basically, the sheet of metal to be blanked is interposed between a punch and a punching die and these members are moved relatively to each other to thus blank out a part of a particular configuration. The configuration is determined by the particular shape of the punch and the punching die. In many instances, it is often desired to provide one or more apertures or perforations within the part being blanked out from the sheet of metal, and accordingly, means are often provided to perform such a piercing operation simultaneously with the blanking operation.

Naturally, it will be understood that once a part or series of parts have been punched or blanked from a large sheet of metal, the outside edges of the individual parts often have burrs, tangs and other imperfections. It is thus desirable to shave or otherwise smooth these outer edge surfaces to provide a clean and even edge on the final part. Of course, it is possible to smooth the edges by a separate sanding or smoothing operation after the blanking has been completed, but such a procedure is more expensive since it involves a separate machining operation. Thus, it would naturally be desirable and beneficial to accomplish the smoothing or shaving operation in cornbination with the blanking or punching operation.

In my aforementioned patent, there was described an arrangement, which, in its most basic sense, accomplished the punching or blanking operation during a downstroke of the apparatus and accomplished the shaving operation during the upstroke of the apparatus. In contrast to the arrangement of my prior patent, however, the present invention accomplishes both the punching and shaving operations during a single unidirectional stroke of the apparatus.

Claims "ice The prime object of the present invention is to provide a method and apparatus which produces blanked and shaved metal parts and which accomplishes both the blanking and shaving operations during a single stroke of the apparatus, preferably, the downstroke.

Another object of the present invention is to provide an improved method and means for accomplishing a seriatim punching and shaving operation to provide smooth edged blanked metal parts.

Another object of the present invention is to provide a combination punching and shaving apparatus for producing sheet metal parts, such apparatus being operable in a simple yet efficient manner to assure that such parts are produced with smooth edges and with the minimum degree of movement of the apparatus itself.

Another object of the present invention is to provide a method and apparatus for punching and shaving sheet metal parts with a higher degree of speed and eiciency than was heretofore possible.

Other objects, advantages and salient features of the present invention will become apparent from the following detailed description which, taken in conjunction with the annexed drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

FIGURES 1-5 are diagrammatic side elevational views, partly in section, showing the progressive operation of apparatus in accordance with the present invention and caapble of performing the method aspects thereof; and,

FIGURE 6 is a top plan view of the apparatus of FIG- URES 1-5.

With continued reference to the drawings, there is shown in FIGURE 1, apparatus in accordance with the principles of the present invention, and suitable for carrying out the method aspects thereof. Such apparatus is generally designated 10 and it includes a generally flat base plate 12 having a pair of spaced apart upstanding guide posts or columns 14. A head plate 16 is mounted in spaced relationship above the base plate 12 and apertures are provided within the head plate so that the guide columns 14 can pass therethrough. As a result, the head plate 16 can be moved toward and away from the base plate 12, with such movement being guided by the columns 14. In considering the stroke of the apparatus 10, if it is assumed that the base plate 12 is fixed, then movement of the head plate 16 toward the base plate can be regarded as the downstroke and movement of the head plate away from the base plate can be considered as the upstroke.

The head plate 16 carries four spaced apart laterally extending pins 18 which serve as pivot pins for mounting four lock mechanisms generally designated 20. The details of these lock mechanisms will be described shortly hereinafter. For the present, it is sufficient to state' that the locking mechanisms 20 releasably engage laterally extending pins 22 which project from a pair of linkage members 24 disposed above the head plate 16.

Each linkage member 24 carries the locking pins 22, extending laterally from opposite sides thereof, and additionally, each member 24 carries a pair of laterally extending pivot pins 26 which serve to mount four depending connecting links links 28. The links 28, in turn, are pivotally mounted at 30 to a Shaving die mounting plate 32 which carries therewithin, a shaving die 34, which is thus more or less suspended by the connecting links 28. Preferably, the shaving die 34 is removably attached to the shaving die mounting plate 32 to enable such die to be replaced, if desired.

A blanking die 36 is carried on the underside of the head plate 16 in spaced relation above the shaving die 34 and the strip of stock material, designated S, from which 3 the parts are to be formed is interposed in the spaced between these dies 34 and 36.

The head plate 16 also carries a pair of centrally disposed and laterally spaced apart upstanding guide posts 38 whose purpose is to position a movable shaving punch guide plate 40. A series of bolts 42 extends between the guide plate 40 and the head plate 16 and compression springs 44 are disposed in surrounding relationship to the bolts 42 to assure that the

plate

16 and 40 are normally urged away from each other.

As can be noted, the shaving punch guide plate 40 is provided along its edges with a pair of raised ridges or `beads 46 which nest cooperatively in grooves or channels 48 formed in the linkage members 24. The guide plate 40 also has a threaded central aperture 50 which receives the end of an elongated bolt 52. A top plate means 54 is provided above the linkage members 24 so that the lower edge of the top plate means 54 abuts against the upper edge of the linkage members 24. The top plate 54 is maintained in position due to the fact that the elongated bolt 52 extends therethrough and threads into the aperture 50 of the shaving punch guide plate 40.

The central axis of the apparatus can be generally considered as the axis passing along the elongated bolt 52. As such, the die openings and punches are positioned along this central axis. More specically, there is provided a shaving punch mounting plate 56 attached beneath a spacer 58 carried on the underside of the shaving punch guide plate 40. Bolts 60 connect from this mounting plate 56 into the enlarged, shoulder portion of a shaving punch 62. A blanking punch 64 is mounted upon the base plate 12 in coaxial alignment with the shaving punch 62. The cross sectional configuration of the punches 62 and 64 is substantially the same, and, quite naturally, openings must be provided within the shaving and blanking dies 34 and 36 respectively to accommodate these punches. Thus a die opening 66 is provided in the shaving die 34 to act as a relief for the piece after it passes through shaving. A similar die opening 68, provided in the blanking die 36, is the die clearance necessary for blanking.

The shaving punch 62 carries a spring loaded pin 70 which functions to strip the blanked piece from the punch to prevent the piece from sticking to the punch after the machining operations have been completed. If it is desired to form the part with one or more holes or apertures therein, a piercing means must be provided to accomplish the piercing operation concurrently with the kblanking operation. To this end, a piercing punch 72 can be provided. This piercing punch is mounted within the shaving punch mounting plate 56 and depends through a bore in the shaving punch 62. An aligned bore 74 must be provided in the blanking punch 64 for receiving the end of the piercing punch 72 during the piercing operation, as will be described in greater detail hereinafter. The bore 74 can extend right through the base plate 12 so that the slugs or pierced pieces from the strip S can drop into a suitable scrap pile.

It will be noted that the base plate 12 includes a series of recesses 76, each of which carries a compression spring 78 aligned generally beneath the connecting links 28. Also, it will be noted that a series of upstanding release pins 80 are carried by the base plate 12, such release pins being engageable with the lock mechanisms for the purpose of operating the same in a manner to be described in greater detail hereinafter.

With the foregoing description in mind, it is believed that the koperation of the apparatus 10 now can be described. In this connection, attention is directed generally to FIGURES 1 through 5. Let it -be assumed that the apparatus is initially in the condition shown in FIGURE 1 and the strip stock S is inserted into the position shown in this figure. As the apparatus starts to operate and the movable assembly starts to descend toward the base plate 12, which is normally fixed in position, the apparatus starts to move from the position of FIGURE 1 to that shown in FIGURE 2. Thus it will be noted from FIGURE .4 2 that the shaving die mounting pate 32 contacts the upstanding compression springs 78 extending above the base plate and starts to compress the same. Naturally, at the same time, the shaving die 34 is moved downwardly past the blanking punch 64 so that the upper surface of the blanking punch 64 passes through the die opening 66 in the shaving die 34 and contacts the underside of the strip stock S.

By the time that the apparatus 10 fully reaches the position shown in FIGURE 2, the blanking punch 64 will have moved to at least the underside of the blanking die 36. Such movement will have forced the strip stock S up into the opening 68 in the blanking die thereby serving to blank the particular piece or part out of the remainder of the strip stock. Also, the piercing punch 72 will pass through the strip stock S and into the opening 74 in the blanking punch thereby forming a suitable hole or aperture in the part being blanked. The shaving punch 62 is elevated, by an amount equal to the thickness of the strip stock S and such elevation necessarily reduces the space or gap 110 between the top of the shaving punch 62 and the bottom of the shaving punch mounting plate 56. Thus, by the time that the apparatus reaches the position shown in FIGURE 2, the blanking and piercing operations will have been completed and the piercing punch 72 itself is projected through the blanked out piece to thus generally maintain the piece in position and prevent it from shifting.

As the downstroke of the apparatus continues from the position shown in FIGURE 2 toward the position shown in FIGURE 3, the release pins start to release or unlock the lock mechanisms 20. At this point, it might be well to consider the specic details of the lock members 20. As can be seen, each lock mechanism 20 includes a body member 82 pivotally mounted upon the pins 18. The body member 82 includes a groove or channel 84 for receiving the locking pins 22 on the linkage members 24. A release arm 86 is pivotally mounted by a pivot pin 88 at the bottom of the body member 82 and the pivot pin 88 is generally aligned beneath the pivot pin 18 which mounts the entire lock mechanism 20. The body member 82 carries a spring biased plunger 90 which is urged against one end of the release arm 86 to normally maintain the same in the position shown in FIGURES 1 and 2. At the opposite end of the release arm 86, an upstanding link plate 92 is provided. The link plate 92 is pivotally mounted at its lower end to the release arm 86, and at its upper end, the link plate 92 carries a roller 94 which engages between the back of the body member 82 `and a lock back-up plate 96 attached by bolts 98 to the edges of the head plate 16. The back of the body member 82 is cut away at its lower portion, as indicated by the reference numeral 100, and an adjustable stop member 102 is carried by the release arm 86 for purposes of limiting the pivotal motion thereof to a predetermined amount.

As can be noted from FIGURE 3, continuing downstroke of the mechanism causes the inner portion of the release arms 86, on the lock mechanisms 20, to come into engagement with the release pins 80 mounted on the base plate 12. Thereafter, as the downstroke continues, the release pins 80 cause the release arms 86 to pivot against the action of the spring biased plungers 90 and as a result. the link plate 92 and the roller 94 are moved downwardly until the roller 94 enters the undercut portion 100 of the lock body. At this time, the lock body 82 is released so that the same can pivot about its pivot pin 18.

Simultaneously, it will be noted that the space or gap between the top of the shaving punch 62 and the bottom of the shaving punch mounting plate 56 gradually diminishes from the size shown in FIGURE 2, when blanking has been completed, to zero as shown in FIG- URE 4 when the locks are completely open. This gap 110 is provided for the purpose of assuring a time lapse between completion of the blanking operation and commencement of the shaving operation.

As will be understood by a comparison of the apparatus in FIGURE 3 with that of FIGURE 4, as soon as the lock bodies 82 have been pivoted far enough to release the lock engaging pins 22 from the lock grooves or channels 84, the full force of the compression springs 78 is directed through the connecting links 28 to the linkage members 24. This causes the linkage members 24 to move from the position shown in FIGURE 3 to that shown in FIGURE 4. Additionally, the shaving die '34 and blanking die 36 are forced toward one another `to thereby clamp the blanked out strip stock S therebetween to prevent it from moving and inadvertently fouling the apparatus.

If attention will now be directed to FIGURE 4, the shaving operation performed by the present invention can now be described. It will be noted from AFIGURE 4 that as the downstroke of the apparatus continues, the top plate 54 presses against the inner ends of the disengaged linkage members 24. It will be noted that the blanked out piece P is now solidly held between the Vshaving punch 62 and the blanking punch 64 and that there is no further gap between the shaving die 34 and the blanking die 36. Instead, it will be seen that between the base plate 12 and the shaving punch guide plate 40, there is asolid column of material formed by the spacer 58, the shaving punch mounting plate 56, the shaving punch 62, the blanked out piece of material P and the blanking punch' 64. This solid column forms a support which applies maximum pressure to the blanked out piece during the shaving operation and prevents anyflexing or twisting thereof, The side ridges or beads 46 on the shaving punch guide plate 40 act as pivot hinges for the linkage members 24.

Thus, as the downstroke of the apparatus continues and enters its final stage, the continued force which the top plate 54 applies to the inner end of the linkage members 24, causes the linkage members 24 to pivot and thereby raise or lift the connecting links 28 in a direction opposite to the downstroke. As the connecting links28 thus move upwardly, the shaving die mounting plate 32 and the shaving die 34 supported thereby are also moved upwardly. This draws the shaving die opening 66 across the outer surface of the blanked out piece P' and such movement continues until, as shown in FIGURE 4, the combined downstroke of the apparatus and upward stroke of the shaving die 34 causes the outer edge of the blanked out piece P to be completely shaved and causes the remainder of the metal strip or stock S to be positively retained between the shaving die 34 and the blanking die 36.

Once the entire downstroke has been completed, the piece P will not only be blanked out from the strip stock S, but the outer edges of the piece will be shaved and any internal openings will have been pierced. As the return or upstroke of the apparatus begins, the springs 44 cause the shaving punch guide plate 40 to be pushed upwardly, thereby pivoting the linkage members 24 outwardly and hence lowering the connecting links 28, the shaving die mounting plate 32 and the shaving die 34 carried thereby. Likewise, the springs 106 react against the bolts 60 which carry the shaving punch 62 and this causes the gap 110 to open again. Thus, the piercing punch 72 is drawn into the shaving punch 62 and this relative movement causes the blanked out piece P to be stripped off of the piercing punch or punches 72. Since the speed of reaction of the springs 44 and 106 is somewhat faster than the return or upstroke of the press, the springs 78 serve as a resisting force which tends to hold the upper part of the apparatus in the position of FIGURE 4.

After the entire return stroke or upstroke has been completed, the linkage members 24 again are re-locked by having the locking pins 22 engage with the grooves or channels 84 in the lock members 20. Thus, as can be seen from FIGURE 5, when the cycle is completed, the final or finished blanked out piece P is resting freely on the top of the blanking punch 64. This piece P, of course, has been blanked, shaved and pierced, and the same can then be removed by an air blast or by some mechanical means, or less advantageously, even removed manually. The slug 112 from the piercing operation drops through the bore 74 in the blanking die 64 and base plate 1`2, while the remaining scrap rests upon the top of the shaving die 34. Since this scrap is usually integrally connected with the remaining part of the strip stock S, the scrap itself can be removed from the apparatus merely by suitably advancing the strip stock until an imperforate part is disposed over the shaving die 34. Then, the foregoing operation can be repeated and a new piece will be blanked, shaved and pierced. Of course, if desired, the Operation of the apparatus, and hence the performance of the method, can be made sequential or automatic by any well known type of control device.

After reading the foregoing detailed description, it should be apparent that the objects set forth at the outset of the specification have been successfully achieved by the present invention.

What is claimed is:

1. In the method of producing formed parts from sheet stock by moving first and second means relatively toward one another as the strip stock is interposed therebetween, the improvement which comprises:

providing a blanking punch assembly on one of said means;

providing a blankingdie assembly on the other of said means;

moving one of said means in a given direction toward the other of said means until said blanking punch assembly contacts said sheet stock and forces at least a portion thereof partially into said blanking die assembly to thereby blank a part out of said sheet stock;

providing a shaving assembly for smoothing the edges of said blanked out part;

moving at least a part of said shaving assembly in a direction opposite to said given direction while Continuing to move said one of said means in said given direction to thereby shave said blanked out part; and

moving said one of -said means in a direction opposite to said given direction after said shaving assembly ceases moving, thereby separating said means and providing a formed part having shaved edges.

2. The improvement defined in claim 1 further including the step of piercing said part as said part is being blanked out of said sheet stock.

3. Apparatus for producing formed parts from sheet material, comprising:

a first plate member including a blanking punch;

a second plate member including an opening aligned with said blanking punch;

guide means between said rst and second plate members to permit one to be moved relatively to the other While maintaining said opening in alignment with said blanking punch;

blanking die means interposed between said first and second plate members;

shaving die means interposed between said blanking die means and said first plate member;

said blanking die means and shaving die means each including a die opening aligned with said blanking punch;

a shaving punch extended through said second plate member opening and at least partially through said blanking die opening;

mounting means coupling said blanking die means and said shaving die means to said second plate member in a manner which permits relative movement between said blanking die means and said shaving die means; and

operating means coupled with said mounting means for moving said blanking die means and shaving die means relative to each other;

said sheet material being insertable between said blanking and shaving die means in alignment with their respective die openings;

said apparatus being operable by moving said first and second plate members relative to one another to cause said Iblanking punch to pass through said shaving die opening into contact with said sheet material to force said sheet material at least partially into said blanking die opening, thereby blanking a part from said sheet material; said operating means being operable after said part has been blanked from said sheet material to move said shaving die means toward said blanking die means thereby moving said shaving punch at least partially into said shaving die opening to smooth the edges on the blanked part while it remains retained in position between said shaving and blanking punches.

4. Apparatus as defined in claim 3 further including a piercing punch movably mounted within said shaving punch and projectable beyond the end of said shaving punch and a bore means formed within said blanking punch in alignment with said piercing punch, whereby, as said piercing punch is projected, it passes through the part retained between said blanking and shaving punches and at least partially into said bore means, thereby piercing an aperture in said part.

5. Apparatus as defined in claim 3 wherein said operating means includes movable linkage means and wherein said mounting means includes connecting link means operatively connected between said linkage means and said shaving die means.

6. Apparatus as defined in claim 5 further including a shaving punch mounting plate which has at least one portion which engages said linkage means and acts as a fulcrum therefor.

7. Apparatus as defined in claim 6 wherein said operating means further includes an additional plate member juxtaposed to said shaving punch mounting plate and engaged with said linkage means, said additional plate member being movable relative to said shaving punch mounting plate to pivot said linkage means about said fulcrum to thereby move said connecting link means and thus move said shaving die means toward said blankng die means for smoothing the edges of said part.

8. Apparatus as defined in claim 7 further including lock means mounted on said second plate member, said lock means including an engaging portion which operatively abuts against said linkage means to prevent said pivotal movement thereof, said lock means further including a lock release means which releases said engaging portion from operative abutting against said linkage means so that said linkage means can pivot.

9. Apparatus as defined in claim 8 further including means carried by said first plate member which actuates said lock release means when said first and second plate members havel been moved relatively to one another for a preselected amount.

10. Apparatus as defined in claim 3 further including compression lspring means carried by said first plate member in alignment with said mounting means for exerting a biasing effect on said mounting means when said first and second plate members have been moved relatively to one another for a preselected amount.

References Cited UNITED STATES PATENTS 1,192,066 7/1916 Jaffe 72-328 2,312,749 3/ 1943 Bullock 72-327 2,985,128 5/1961 Henrickson 72-328 3,216,299 11/1965 Stoeckli 83-160 3,236,088 2/1966 Moller 72-328 3,372,569 3/1968 Bozek 72-335 3,274,818 9/1966 Henrickson 72--336 CHARLES W. LANHAM, Primary Examiner E. M. CoMBs, Assistant Examiner U.S. Cl. X.R.