US3357078A - Apparatus for punching interlocking tabs in steel strips - Google Patents

Description

D 12, F. J. MOLTCHAN APPARATUS FOR PUNCHING INTERLOCKING TABS IN STEEL STRIPS Filed Aug. 1, 1966 cJ. M01522? Floyd 7 ATTORNEY.

United States Patent l 3,357,078 APPARATUS FOR PUNCHlNG INTERLOCKING TABS IN STEEL STRIPS Floyd J. Moltchau, 4450 Lake Park Road, Youngstown, Ohio 44512 Filed Aug. 1, 1966, Ser. No. 569,144 4 Claims. (Cl. 29--21.1)

This invention relates to strip material handling apparatus and more particularly to apparatus for joining the leading end of one section of steel strip to the trailing end of an adjacent section so that the joined sections can continue through a processing or production line in a continuous manner.

The principal object of the invention is the provision of apparatus for forming interlocking tabs in steel strips and shaping the interlocking tabs so as to decrease the relative size thereof sufiiciently to permit the shaped interlocking tabs to move freely out of the apparatus.

A further object of the invention is the provision of a simple inexpensive and quick acting apparatus for punching interlocking tabs in steel strips arranged to deflect the steel strips to be joined by the interlocking tabs downwardly into one part of the apparatus where the interlocking tabs are formed and interlocked and subsequently, elevating the steel strips and interlocked tabs out of that part of the apparatus so as to permit the joined steel strips to move freely relative to said apparatus.

Several methods of joining adjacent end portions of steel strips to one another have been heretofore known and used in the metal working arts. Primarily, these have comprised devices for welding the strips to one another and such devices work effectively but are relatively expensive and require a considerable time pause in the portions of the strips to be joined which necessitate large loop sections in the strip to accommodate the same particularly in a continous mill or production line set up.

Other proposals heretofore made have included devices for stitching or forming interlocking tabs. These have generally failed due to the inherent problem of freeing the interlocking tabs or stitched portion of the strip material from the forming or stitching apparatus. The present invention provides a unique apparatus having a relatively wide pass line or area therethrough through which the strips to be joined may freely pass. At such time as the superimposed adjacent ends of two sections of the steel strip are present in the apparatus the appara tus moves toward the strips, engages the same, punches the interlocking tabs and deflects them downwardly while altering the transverse shape and size of the same so as to make possible the immediate freeing of the deflected interlocked tabs from the apparatus which performed the actual interlocking operation.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination arrangement of parts and in the details of construction hereinafter described and claimed, it being the intention to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

The invention is illustrated in the accompanying drawing, wherein:

FIGURE 1 is a side elevation of the apparatus for punching interlocking tabs in steel strips showing the same in fully engaged tab forming position.

FIGURE 2 is a side elevation of the interlocked steel strips.

FIGURE 3 is a top plan view of the interlocked steel stri s.

P IGURE 4 is a side elevation of the interlocked steel 3,357,078 Patented Dec. 12, 1967 strips showing the interlocking tabs under tension and their relative movement responsive thereto.

FIGURE 5 is an expanded cross section on line 5-5 of FIGURE 2.

FIGURE 6 is an expanded cross section similar to FIGURE 5 showing a modified transverse configuration of the interlocking tabs.

By referring to the drawings and FIGURE 1 in particular, it will be seen that a die 10 is illustrated positioned below a horizontal pass line and includes a vertical opening 11 therein in which a punch 12 is adapted to be engaged when the same is moved downwardly by a punch retainer 13 which in turn is carried by a movable top die shoe as will be understood by those skilled in the art. The die 10 is mounted on a bottom die shoe 14 which is partially illustrated and which slidably positions a spring retainer 15 in which a suitable spring device 16 is located. The upper end of the spring retainer 15 supports a vertically movable ejector 17 which is positioned alongside a form steel 18 which is also located in the die 10 and in the vertical opening 11 thereof. A stripper 19 which is apertured as at 20 is positioned in spaced relation above the die 10 and below the punch retainer 13 and arranged so that the punch 12 is reciprocal through the opening 20.

In FIGURE 1 of the drawings broken lines illustrate a pair of superimposed steel strips. The leading end 21 of one of the strips is shown positioned on the trailing end 22 of the other of steel strips. When the apparatus for punching interlocking tabs in these steel strips is actuated and the interlocking tabs formed thereby the apparatus including the punch 12 and the form steel 18 and the ejector 17 are in the position illustrated in FIG- URE 1 and a pair of superimposed tabs 23 and 24 are formed respectively in the strips 21 and 22 and deflected downwardly in the forming operation. The punch 12 has an angular concave metal shaping surface, the uppermost portion of the concave surface being indicated by the numeral 25 and the form steel 18 has an angularly disposed convex metal shaping surface 26 generally matching the concaveconfiguration 25 in the punch 12. Thus, when the punch 12 engages the superimposed steel strips 21 and 22 it first punches the tabs 23 and 24 therefrom in a punching action and then moves on downwardly to shape the tabs 23 and 24 by means of the configurations 25 and 26. The concave configuration 25 and the convex configuration 26 in the punch 12 and form steel 18, respectively, are such that the metal of the tabs 23 and 24 is humped upwardly in their center longitudinal section as best seen in the cross section in FIGURE 5 of the drawings or in the side elevation of FIGURE 2 of the drawing whereby the effective overall width of each of the tabs 23 and 24 is reduced relative to the openings in the strips 21 and 32 from which the tabs were punched.

Those skilled in the art will observe that tabs 23 and- 24 are not completely separated from the strips 21 and 22 but remain joined thereto along their foremost edges. The tabs are themselves deflected to an angular position below the superimposed strips 21 and 22 and the longitudinal centrally positioned hump shape formed in the tabs 23 and 24 extends from their point of junction with the strips 21 and 22 downwardly through substantially their entire length. -By creating the longitudinal hump in the tabs 23 and 24 their effective width is reduced and they are, therefore, relatively free of the surrounding die 10 and in a position and shape so that the ejector 17 moved by the spring device 16 lifts them upwardly and out of the opening 11 in the die 10 as soon as the punch 12 is retracted upwardly. The stripper 19 prevents the strip 21 from following the punch 12 upwardly when it retracts as it is positioned in fixed relation to the pass line by suitable supporting arms 27.

By referring now to FIGURES 2 and 3 of the drawings, a side elevation and a top plan view of the strips 21 and 22 may be seen, and it will be observed that the tabs 23 and 24 are shown after the same have moved out of the apparatus for punching the interlocking tabs therein and that they are still in the as formed relation.

By refrring now to FIGURE 4 of the drawings, it will be seen that the tension on the trailing end of the strip 22 moves the same relative to the strip 21 and thus shifts the position of the interlocking tabs 23 and 24 and that in such shifted position the tab 23 underlies a portion of the strip 22 and thereby holds the leading end of the strip 21 in fixed relation thereto thereby achieving the principal object of the invention.

It will occur to those skilled in the art that while the embodiment of the invention illustrated herein shows only one pair of interlocking tabs in rather narrow steel strip, the usual application of the apparatus to a strip line will require a plurality of the punches 12 and dies and form steels 18 as shown herein, arranged in a line transversely of the pass line and the steel strip moving therealong. In such an arrangement the plurality of punches 12 and dies 10 move toward one another and the steel strip simultaneously and form a transverse line of punched interlocking tabs thereacross.

By referring now to FIGURES 4 and 5 of the drawings, it will be seen that when the tabs 23 and 24 are punched and formed as hereinbefore described, the central longitudinal portion of each of the tabs forms a raised angularly disposed ridges 28 and 29 respectively and that the movement of the metal of the tab into the ridge 28 or 29 reduces their effective width as clearly shown in the top plan view of FIGURE 3 and with respect to the punched opening 30 from which the tab 23 was formed.

In FIGURE 5 of the drawings vertical lines spaced on either side of the superimposed tabs 23 and 24 indicate the width of the tabs 23 and 24 at the time they are punched from the strips 21 and 22 while the actual cross sectional views thereof show the same in their reduced width resulting from their appropriate shaping as disclosed herein.

In FIGURE 6 of the drawings a modification of a pair of interlocking tabs 31 and 32 may be seen and it will be observe-d that these are shaped in a modified transverse configuration which also effectively reduces the width of the tabs. It will thus be seen that an apparatus for punching interlocking tabs in steel strips so that the tabs may be freely moved out of the punching die and apparatus has been disclosed and which apparatus accordingly meets the several objects of the invention. It will occur to those skilled in the art that when the punch 12 and die 10 move away from one another as hereinbefore described, after completing the formation of the interlocking tabs 23 and 24 and shaping the same, the vertical spacing between these respective parts increases substantially and sufficiently to permit the tabs 23 and 24 to be moved upwardly thereinto by the ejector 17 and to permit the strips 21 and 22 to move freely between the metal working parts of the apparatus.

Having thus described my invention, what I claim is:

1. Apparatus for punching interlocking tabs in superimposed steel strips consisting of a die, said die having a cutting edge in the shape of said tabs, and a punch registrable with said die, said punch having a cutting edge in the shape of said tabs, a portion of said die having a forming surface, a portion of said punch having a matching forming surface, said forming surfaces arranged to move the metal of said tabs formed thereby to superimposed shapes of a size smaller than the areas from which they were formed.

2. The apparatus set forth in claim 1 and wherein said punch and die are formed to shape said tabs so that they are each joined to said steel strips at one of their ends and deflected downwardly relatively thereto.

3. The apparatus set forth in claim 1 and wherein said punch and die are formed to shape said tabs to include axial extending ribs on their upper sides.

4. The apparatus set forth in claim 1 and wherein said forming surface in said punch consists of an angular positioned concave channel and the forming surface of said die consists of an angular positioned convex ridge.

References Cited UNITED STATES PATENTS 184,397 11/1876 Macumber. 2,811,880 11/1957 Williams.

RICHARD H. EANES, JR, Primary Examiner.

Claims (1)

1. APPARATUS FOR PUNCHING INTERLOCKING TABS IN SUPERIMPOSED STEEL STRIPS CONSISTING OF A DIE, SAID DIE HAVING A CUTTING EDGE IN THE SHAPE OF SAID TABS, AND A PUNCH REGISTRABLE WITH SAID DIE, SAID PUNCH HAVING A CUTTING EDGE IN THE SHAPE OF SAID TABS, A PORTION OF SAID DIE HAVING A FORMING SURFACE, A PORTION OF SAID PUNCH HAVING A MATCHING FORMING SURFACE, SAID FORMING SURFACES ARRANGED TO MOVE THE METAL OF SAID TABS FORMED THEREBY TO SUPERIMPOSED SHAPES OF A SIZE SMALLER THAN THE AREAS FROM WHICH THEY WERE FORMED.

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