US3034783A

US3034783A - Press feeding method and apparatus

Info

Publication number: US3034783A
Application number: US52235A
Authority: US
Inventors: Christa Leonard Leon
Original assignee: American Can Co
Current assignee: Primerica Inc
Priority date: 1960-08-26
Filing date: 1960-08-26
Publication date: 1962-05-15
Anticipated expiration: 1979-05-15

Description

May 15, 1962 1 l.. cHRlsTA PREss PEEDING METHOD AND APPARATUS 7 Sheets-Sheet 1 Filed Aug. 26, 1960 May 15, 1962 l.. l.. cHRlsTA 3,034,783

PRESS FEEDING METHOD AND APPARATUS Filed Aug. 26, 1960 7 Sheets-Shea?l 2 Jffz. A

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AGE/V7 May 15, 1962 L. l.. cHRlsTA PRESS FEEDING METHOD AND APPARATUS '7 Sheets-Sheet 3 Filed Aug. 26, 1960 h NS INVENTOR.

a N E May 15, 1962 L.. L. cHRlsTA PRESS FEEDING METHOD AND APPARATUS 7 Sheets-Sheet 4 Filed Aug. l26, 1960 LTS Age/vr May 15, 1962 l.. L cHRlsTA 3,034,783

PRESS FEEDING METHOD AND APPARATUS Filed Aug. 26, 1960 7 Sheets-Sheet 5 May 15, 1962 L.. l.. cHRxsTA PRESS FEEDING METHOD AND APPARATUS 7 Sheets-Sheet 6 ,M QM Nm.. R Ow O 7 j 1 WM N ,lll/ W M Ffq 11|||l/Y1|\|\|||l||/v I A M y lll n, 1. w n m E m W Filed Aug. 26, 1960 May 15, 1962 1 L. cHRlsTA PRESS FEEDING METHOD AND APPARATUS '7 Sheets-Sheet '7 Filed Aug. 26, 1960 INVENToR.

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M 1 y@ u A N ml Unite States 3,034,783 PRESS FEEDING METHD AND APPARATUS Lepnard Leon Christa, San Jose, Calif., assigner to Amerlean Can Company, New York, NX., a corporation of New Jersey Filed Aug. 26, 19st), ser. No. 52,235 11 Claims. (ci. 271-14) The present invention relates to the feeding of strips into presses, and has particular reference to a method and apparatus for feeding scroll cut strips into strip feed presses in such manner that there are no gaps between the strips so that consequently the cutting dies of the press never miss a cutting stroke.

Until recently, the can making industry received all of its supplies of tin plate from the steel mills in the form of precut, straight edged, square or rectangular sheets, the cutting and packaging of such sheets being done at the steel mills. In the past few years, however, a considerable percentage of such supplies of tin plate has lbeen received by the can manufacturer in the form of coils many thousands of feet in length, the cutting of such coils into sheets now being done by the can manufacturer in his own plants. Considerable economies are made possible by this development, especially in the formation of can ends and other circular articles, since the coils are now being cut by scroll edged dies into large sheets having two opposed scroll cut edges, and these large sheets are then subdivided without waste into scroll strips each of which contains a double row of blank spaces from which the can ends are subsequently cut, the blank Spaces in one row being longitudinally offset or staggered with respect to those in the other row a distance equal to one-half of a blank space.

These scroll edge strips are then fed into a strip feed press in which a pair of staggered cutting dies cut them into can ends. When the scroll edged strips are fed into such dies, normal practice has been to provide a gap equal to a full blank space between successive strips in order to provide room behind the strips for the feed fingers which feed them into the dies.

Because of the necessities of practical die construction, the cutting dies are staggered from each other a distance equal to one and a half blank spaces. As a result of the combination of this spacing between the dies and the gaps between successive sheets, there are two strokes of the press for each strip in which one or the other of the cutting dies comes down into the gap between the strips and cuts air, as such wasted, non-productive cut is termed in the industry.

The present invention eliminates this cutting of air by eliminating the gaps between successive strips as they are fed into the cutting dies.

In the usual strip feed press, the strips are Stacked in a magazine from which each strip is pulled individually by suction cups which lift it into the plane of the feed table of the press. Thereafter, the suction cups are devacuumized, and one of the long edges of the strip is engaged by spaced inserter fingers which feed the strip laterally across the feed table and into feeding position thereon, whereupon its trailing short edge is engaged successively by a plurality of reciprocating, spring-pressed feed dogs, spaced one blank length apart, which feed the strip longitudinally `and intermittently into the cutting dies.

To eliminate the present 'spacing between the strips, the instant invention contemplates that the lateral feeding of the strip across the feed table be started sooner than usual, so that the forward portion of the strip which is being inserted into the feed table overlaps the trailing portion of the preceding strip which is being fed longitudinally along the feed table and into the cutting dies.

3,il34,783 Patented May 15, 1962 Since the underlying strip is moving longitudinally relative to the overlying strip, the length of overlap decreases, but before it disappears entirely, the overlying strip reaches its fully inserted position and is engaged by the longitudinally reciprocating feed dogs and starts its longitudinal motion into the dies. Thereafter both -strips move together, the succeeding strip overlapping the one ahead of it only slightly, the overlapped portions of each strip comprising portions of the scrap areas which must necessarily be provided in each blank space around the potential can end therein so that the cutting dies are enabled to make a clean cut Without feather edges. Consequently, the lapped portions of the strips, which comprise double thicknesses of stock, are never actually cut by the dies, but become parts of the strip skeletons.

In order to insure lthat the reciprocating feed dogs engage the underlapped, trailing edge of the leading strip during the time the strips are being fed longitudinally along the feed table, the rear edge of the leading sheet is pressed downwardly by spring buttons in order to space the overlapped portions of the strips apart t0 provide a space in which the feed dogs may operate.

In order to prevent interference between the strips and to prevent any burrs which might be present on the edges of one of the strips from scratching the other strip as the succeeding strip is inserted into the feed table, means are provided to space the overlapping portions of the strip vertically from each other during the time the succeeding strip is being inserted into the feed table.

As a result of these features the present invention successfully fulfills its main objective of providing a practical method and apparatus for feeding strips to the dies of a strip feed press in such manner as to fully utilize the cutting efficiency of the press.

Another object of the present invention therefore is the provision of an apparatus for feeding strips into a press in slightly overlapped relationship so that the gaps 'between successive strips are eliminated and the dies of the press never cut air.

Another object is the provision in such an apparatus of means for positively holding the overlapped edges of successive strips apart so that the feed fingers are enabled to engage the trailing edge of the leading strip and feed it into the press.

Yet another object isv the provision of means for preventing scratching of the strips as the succeeding strip is fed laterally across the preceding strip and into position on the feed table.

Numerous other objects and advantages of the invention will be apparent as it is better understood from theV following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

`FIGURE l is a side elevation of a press feeding mechanisrrl embodying the principles of the instant invention;

FIG. 2 is a vertical section taken substantially along the line 2 2 of FIG. l;

FIG. 3 is a vertical sectional View on an enlarged scale taken substantially along the line 3 3 of FIG. l';

FIG. 4 is a sectional detail taken substantially along the line i--l of FIG. 3;

FIG. 5 is a view similarto FIG. 4 but showing how successive sheets are maintained in spaced, overlapped relationship as the succeedingsheet is inserted into the feed table, the position of the sheets 4in this View corresponding to the position shown in FIG. 8;

FIG. 6is a vertical sectional view taken substantially along the line 6--6 of FIG. 3, the strip which is shown in FIG. 3, being omitted in order to more clearly bring out the details of construction of the various parts of the mechanism.

FIG. 7 is an enlarged sectional detail of portions of the mechanism shown in FIG. 6, the view showing successive strips in position on the feed table and being moved longitudinally in unison into the press by the feed dogs of the press feeding mechanism of the instant invention;

FIG. 8 is a vertical sectional view taken substantially along the line 8-8 in FIG. 7;

FIG. 9 is a plan view of a portion of the feed mechanism of the instant invention, taken substantially along the line 9-9 of FIG. 6, parts being broken away, the view illustrating successive strips in the position they occupy during the first step of the present method invention; and

FIGS. l0, l1, l2 and 13 are plan views illustrating the succeeding steps of the present method invention.

As a preferred and exemplary embodiment of the instant invention, the drawings illustrate a press feeding mechanism, generally designated by the letter F, which feeds double row, scroll cut strips S to the cutting and forming dies D of a strip feed press P, only fragmentary portions of which are shown.

` As best seen in FIG. l0, the strips S are formed with scroll-cut inner and outer longitudinal edges I and O, and scroll-cut front and rear edges F and R, respectively, the configuration of the scroll cuts being such as to form a muliplicity of blank spaces B, each of which is of suf- :licient size to contain a potential can end or other article which is subsequently cut from the blank space B along a circular line C by the cutting and forming dies D. Each strip S contains two rows of blank spaces B, one row being longitudinally offset from those in the other row a distance equal to one-half of a blank space. Sufficient scrap material is provided in each blank space B to provide a scrap allowance which extends completely around each circular line of cut C and insures the formation of a clean cut by the dies D.

As seen in FIGS. l, 2 and 3, the press feeding mechanism PF includes a longitudinally extending frame which is bolted to the main frame 22 of the strip feed press P in longitudinal alignment with the dies D. The frame 20 is formed generally in the shape of an inverted U and its upper wall 24, together with a guide plate 25 which is formed with a guide wall 26 and a shelf 27, form a feed table T along which the strips S are fed longitudinally into the dies D by a plurality of reciprocating feed fingers or dogs 28 which operate in a groove 29 which is cut into the feed table T. The feed table T is covered by a feed table cover plate 30 which on one side is spaced above the feed table T a distance somewhat greater than the thickness of a strip S, as will later be seen, to form a feed table slot 31 into which the strips S are inserted. The plate 30 is supported by a pair of arms 32 which are secured to the frame 20.

'Ihe feed lingers 28 are pivotally mounted on pivot pins 33 which are secured to feed finger holders 34 which are adjustably secured in a groove 36 formed in a carrier bar 38 (see FIGS. 3 and 6). Each feed linger 28 is formed with a wide front portion 39 which is provided with a lateral bevel 40 and a forwardly facing V-shaped front edge 41 which engages the trailing edges of the strips S to propel them along the feed table. The front linger portion 39 is biased to its operative, raised position by a leaf spring 42 which is secured in the holder 34, the upward movement of the feed finger 28 being limited by a stop bar 44 which forms a part of the holder 34 and engages the tail portion 46 of the feed finger 28 to limit the counter-clockwise rotation which is imparted to the feed linger 28 by the spring 42.

`One end of the feed finger carrier bar 38 is adjustably secured by means of a clamp 50 to a rod 52 which is slidably mounted in bearings 53 formed in the frame 20 and which is driven by a crank wheel 54 which is rotated from the main drive of the press (not shown) in any suitable manner, the rotary motion of the crank wheel 54 being converted to a reciprocating motion of the rod 52 by a crank arm 56, one end of which is connected to the crank wheel 54 and the other which is connected to the rod- 52. As a result, the carrier bar 38 and the feed lingers 28 which are carried thereon are reciprocated in the groove 29 longitudinally of the feed table T.

The strips S are held in a magazine M, which is secured to the frame 20 in any suitable manner, and are lifted individually therefrom by a vacuum lifter unit which comprises three suction cups 60 which are mounted at the lower ends of hollow slide rods 62 which are suitably connected to a source of vacuum (not shown). The rods 62 are mounted for vertical reciprocation in upper and

lower bearings

64, 66 respectively, of brackets 68 which are bolted onto a cross-plate 70 which is carried by a pair of vertical supports 72 which are formed integral with the arms 32 (see FIG. l). The rods 62 are all secured by means of couplings 73 to a horizontal carrier rod 74 which is connected to the outer ends of a pair of rocker arms 76 by a pair of connecting links 78 as best seen in FIGS. l and 2.

Each rocker arm 76 is freely mounted on a crossshaft 80 which is carried in a bearing 82 formed at the upper end of a support bracket 84. At its opposite end, each rocker arm 76 is secured to a vertical rod 86 which at its lower end is associated with suitable cam means (not shown) which imparts to the rocker arm 76 a reciprocatory motion which is converted to the necessary oscillatory motion of the rocker arm 76.

The topmost strip S2 in the magazine M is lifted to the level shown in FIG. 3 by the suction cups 60, and its upper surface, adjacent its front end, is thereby brought into engagement with the lower surface of a magnet 100 which is secured to the outer face of the feed table cover plate 27. The vacuum in the suction cups 60 is then cut olf and the cups 60 are vented, thus releasing their grip on the strip S2. As soon as this occurs, the strip S2 is inserted into the feed table slot 31 by a pair of inserter or cross-feed yarms which operate in

slide bearings

92, 94 which are suitably secured to the frame 20. The inserter arms 90 `at their outer ends carry a pair of depending inserter fingers 93 which engage the longitudinal outer edges O of the strips S.

The upper surface of each inserter arm 90 is formed with a plurality of teeth 95 which are engaged by the teeth of =a gear segment 96 (see FIGS. Zand 3) which is freely mounted for oscillation on the shaft 80 and is formed with an integral arm 98 which is connected to the upper end of a vertical rod 100, the lower end of which is associated with suitable means such as a cam (not shown) which reciprocates it vertically, the vertical reciprocation of the rod 100 imparting an oscillatory motion to the gear segment 96 which in turn imparts a reciprocatory motion to the inserter arms 90 which enables them to insert the strips S successively into the feed table slot 31.

It will be understood that prior to the time the sheet S2 has been lifted from the suction cups 60 to the position shown in FIG. 3, the preceding sheet S1 had been inserted into the feed table slot 31 and its inner edge I brought into engagement with the guide wall 26 of the guide plate 2S by the inserted arms 90. During its insertion, the strip S1 had come into contact with the lateral bevels 40 of the feed ngers 28 and had forced the feed fingers 28 downwardly against the pressure of their leaf springs 42. Thereafter, the reciprocatory motion of the carrier bar 38 had caused the rearmost feed finger 28 (the one to the left yas seen in FIG. 10) to fall slightly to the rear of the rear edge R of the strip S1, with the result that thatA finger had been rocked upwardly by its leaf spring 42, so that the next forward stroke of the carrier bar 38 had brought its front edge 41 into engagement with the rear edge R of the strip S1 and had ycaused it to advance the strip a distance Iequal to the length of one blank space B. On succeeding strokes of the carrier bar 38, this action had been repeated by the successive feed lingers 28 with the result that the strip `S1 vhad been advanced longitudinally :along :the feed table T in a step by step lfeeding action until it had reached the position shown in FIGS. 3 and 12, 4at which time the Alateral insertion of the strip 'S2 into the slot 31 is begun.

-In this position, a portion of the rear end of the strip S1 rests upon :a rais-ing block 102 which is disposed in a recess 104 formed on the feed table T. The upper surface 105 of the block 102 is raised somewhat above the normal level of the upper surface of the adjacent feed table wall 24 so that a gap which is substantially equal to the thickness of one .strip S is created between the block surface 105 Iand the bottom surface of the feed table cover plate 30, for a purpose which will be shortly explained. The raising block y102 is supported by four adjustable studs 106 which in turn .are carried by a suppont 4plate 1'0'7 which is bolted to the fname 20, a plurality of springs 108 being interposed between the block 102 and the plate 107 to provide -a floating mounting for the block 102 which permits it to move downwardly in the event a double strip is inadvertently fed into 4the slot 31.

FIG. 9 shows .a plan view of the relative positions of the strips SS1 and S2 at the beginning of the forward stroke of the carrier bar 3S and an inserting stroke of the inserte/r bars `90, which strokes are so timed as to start substantially simultaneously. As a result of these strokes, the strip Sl is advanced along the feed table T toward the dies D as the strip S2 is moved laterally into the feed table slot 31. As seen in FIGS. 3 an-d l2, the forward end of the strip S2 is held upwardly against the underside o-f the cover plate 30 by the magnet 100 and is fed laterally over `a ramp 110 which is secured to the magazine M yand which also serves to prevent the forward portion of the strip S2 from sagging.

As the strip S2 approaches the block V102, the forward movement of the strip S1 carries its rear edge R beyond the raised portion of the block 102 and into position olver a .step 112 which is formed in the front portion of the block 102, thus permitting the rear portion of the strip S1 to .drop down onto the step 112 land reach a level which is `considerably below the level of the incoming strip S2. Tihe yupper surface of theframe wall 24, from the beginning of the step 112 to the dies D, is also stepped downwardly to provide a lower level 114, as clearly seen in FIG. 4, `so that the whole of the strip S1 is spaced below the strip S2. FIG. l shows the position of the strips S1 and S2 at the ycompletion of the forward stroke of the carrier bar 33.

During the return stroke of the `carrier bar 38, fthe strip S2 continues its lateral motion with the result that its forward portion overlaps the rearward position of the strip S1, as clearly seen in FIG. 11, which shows the carrier bar 38 at the completion of its return stroke. During this portion of its lateral motion, the strip S2 rides onto the raised surface 105 of the raising block 102, and this block 102, in cooperation with the ramp 110 and the magnet 100, positively maintain the strip S2 at a level above the level of the strip S1, thus preventing any interference between the strips and at the same time keeping any burrs which might be presenten the scroll cut edges of either of the strips from contacting the other strip and scratching its surface during this strip inserting operation.

On the next forward stroke Vof the canrier bar 38, the strip S1 is moved forwardly one blank length, while the strip S2 continues its :lateral motion and fully enters the feed table slot 31, so that its edge I contacts the `guide Wall 25. FIG. l2 shows the strip S2 in this position, wherein its front edge F slightly overlaps the rear edge R of the strip S1, the overlapped portions comprising 6 the marginal scrap portions which are present in these areas of the strips.

On succeeding forward strokes of the carrier bar 38, both strips S1 and S2 are engaged by feed ngers 28 yand are fed forward longitudinally in unison `and in overlapped relationship along the feed table T, as seen in FIG. 13.

As they approach the dies D, the strips ride off the end of the feed table T and onto a pair ofv support plates 120, 122 (see FIG. 9) which are suitably mounted on the die bed DB of the press P, and form portions of the die table, `the vplate forming lan extension of the depressed portion 114 of 'the fra-me 20 and the plate 122 being formed with a shelf 123 which forms an extension of the shelf 27 of the guide plate 25. The carrier bar 38 and the two endmost feed ngers 28 carried thereon project beyond the end of the feed table T and operate bet-ween the plates 1201, 122.

In order to clamp the strips S1 so that there is no chance of its being moved as the feed fingers 28 slide beneath it on the return stroke of the carrier bar 38, a clamp 124 is pivotally mounted on a pivot pin 126 which is mounted adjacent the end of feed table cover plate 30 (see FIGS. 6 and 9). The end of the clamp 124 is formed into a pair of split fingers 127, which are urged by a spring 128 into engagement with the ystrip S1 to press it against the plates [120, 122.

During the simultaneous movement of the strips S1 and S2 toward the dies D, the rear edgeR of the Strip S2 is exposed and is easily engaged by the feed dogs 28 which feed the strip S2 along the feed table T. However, the rear edge R of `the strip S1 is not exposed, but underlies the front edge F of the strip S2 so that the feed fingers 28, which are held in depressed position by the strip S2, could not under normal circumstances cleanly and reliably engage the rear edge R of the strip S1. To overcome this, means are provided to depress the rear edge R of the strip S1 below the level of the overlying front edge F of the strip S2 to separate these lapped edges so that the strip engaging faces 41 of the feed iingers 28 are enabled to cleanly engage the rear `edge R of the strip S1.

To accomplish this, the shelf 2.7 of the guide plate 25 and the shelf 123 of the plate 120 are formed with a series of inclined steps 130 which are spaced apart a distance equal to the length of a feed `stroke of the carrier bar 38, and a corresponding number of spring buttons 132 and leaf springs 1:34 are mounted above the steps 130 to engage the strip S11 adjacent its rear edge R just ahead of the front edge F of the -strip S2 at the end of every feed stroke of the carrier bar 38 Aand press the rear edge R of the Strip S1 downwardly into the steps 130 to thereby space the rear edge R of the `strip S1 below the level of the front edge F of the strip S2, as best seen in FIG- URE 7.

The spring buttons 132 are mounted in bores formed in the feed table cover plate 30 `and are pressed downwardly lby coil springs 136 which are disposed within the buttons 132 and confined between the smoothly rounded nose 13S ofthe buttons 132 and set screws 140` which are threaded into the cover plate 30. Each button 132 is formed with a stop collar 142. VThe leaf springs 134 are mounted in recesses `144 formed in the undersurface of the clamp 124.

As best seen in FIG. 7 all of the spring buttons 132 and leaf springs 134, except one, are held in upward position by the strips S1 and S2 at any given time by virtue of the fact that these strips ride upon yand bridge the high portions 145 of the inclined steps 130, and the stiffness of the thus supported strip portions is suiiicient to resist the downward pressure of the buttons 132 and leaf springs 134. However, the downward pressure of the buttons 132 and springs 134 is suflicient to flex the unsupported rear edge portion of the strip S1 downwardly onto the inclined step beneath it as that edge portion passes successively beneath the buttons 132 and springs 134 as the strips are fed intermittently by the feed ngers 28. During each feed stroke of the carrier bar 38, the rear edge portion of the strip S1 rides up on an inclined step 130 and then is pressed by the next button 132 or spring 134 into the next inclined step 130. Thus the feed fingers 28 on each feed stroke are enabled to cleanly engage the depressed rear edge R of the strip S1, even though they themselves are maintained in a depressed position by the strip S2, and the danger of misfeeding the lapped strip S1 is eliminated.

As a result, the strips S1 and SZ pass through the cutting dies D, which `are disposed in staggered relationship one and a half blank lengths apart and occupy the positions designated as D1 and DZ in FIGS. 9 and 10, in overlapped relationship, thus permitting the dies D to cut two can ends during each cutting stroke, the absence of a gap -between the strips resulting in maximum cutting efficiency of the press P.

As each strip S is fed along the feed table T, the succeeding strip in the magazine M is inserted into the feed slot 31 in the manner just described, and the whole press feeding operation is repeated, thereby insuring a continuous procession of overlapped strips into the dies D.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of parts of the apparatus mentioned herein and in the steps and their order of accomplishment of the method described herein, without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the apparatus and method hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. The method of feeding strips, comprising the steps of moving successive strips laterally into longitudinal alignment with a treating machine, overlapping only the trailing and the leading adjacent marginal edge portions of successive strips during said lateral movement, spacing said overlapped marginal edge portions apart vertically, and pushing against the trailing marginal edge portions of said strips to move said strips longitudinally and simultaneously into said treating machine in said overlapped relationship.

2. The method of feeding strips, comprising the steps of moving a strip laterally into longitudinal alignment with a treating machine, moving said strip longitudinally toward said treating machine While simultaneously moving a succeeding strip laterally into alignment with said treating machine to thereby overlap a portion of said longitudinally moving strip, and thereafter moving both of said strips longitudinally into said treating machine in overlapped relationship.

3. The method of feeding strips comprising the steps of placing a supply of strips in a stack in lateral alignment with the feed table of a treating machine, moving a strip from said stack in a lateral path onto said feed table and propelling it in a longitudinal path along said feed table toward said treating machine, said longitudinal path being spaced below said lateral path by a depth not less than the thickness of a said strip moving the succeeding strip from said stack along said lateral path to bring the forward edge of said succeeding strip into overlapped relationship with the trailing marginal edge of said preceeding strip, pressing the overlapped portions of said strips apart, and pushing against the rear edges ofvboth of said strips to propel them simultaneously along said feed table and into said treating machine in said overlapped relationship.

4. A mechanism for feeding strips, comprising in combination a strip support, means for placing strips successively onto said support in longitudinal alignment with the rear edge of said preceding strip and the forward edge of its next succeeding strip in overlapped relationship, feeding means engageable against the rear edges of each of said strips for propelling them longitudinally and simultaneously along said support in said overlapped relationship, and means for spacing said overlapped strip edges apart to facilitate said engagement of said feeding means against the rear edges of said preceding strips.

5. A mechanism for feeding strips, comprising in combination, a feed table, means for placing strips successively onto said feed table with the rear edges of the preceding strips in underlapped relationship to the forward edges of the succeeding strips, reciprocating means disposed in said feed table for engaging the rear edges of said strips to advance them valong said feed table, a longitudinal support shelf on one side of said reciprocating means for supporting a longitudinal marginal portion of said strips, a cut away portion formed in said shelf, and presser means positioned above said cut away portion for depressing the rear edges of the preceding strips into said cut away portion when they pass beneath said presser means to space said rear edges beneath the adjacent forward edges of the succeeding strips to thereby expose them to said feeding means.

6. The mechanism of claim 5 wherein said reciprocating means comprise a plurality of spring backed feed fingers which successively engage said strips to advance them intermittently along said feed table.

7. The mechanism of claim 6 wherein said support shelf is provided with a plurality of inclined steps, and wherein spring means are positioned above said inclined steps to press the rear edges of said strips into said steps as the strips are advanced along said feed table by said feed fingers.

8. A mechanism for feeding strips comprising in combination, a feed table, a cover plate for said feed table, inserting means for moving strips laterally yacross said feed table and into fully inserted position between said feed table and said cover plate, a plurality of reciprocating feed fingers operable in said feed table for feeding said fully inserted strips longitudinally along said feed table, the relative timing of said inserting means and feed fingers being such that the insertion of each succeeding strip is completed before the next preceding strip has been moved longitudinally past it so that each succeeding strip slightly overlaps the strip preceding it, and means for depressing the trailing edge of each such preceding strip to expose it to said feed fingers so that said preceding and succeeding strips are fed along said feed table in unison in lapped relationship.

9. The mechanism of claim 8 wherein means are provided to hold each strip against the feed table cover plate while it is being inserted to prevent it from contacting the strip already on the feed table.

l0. The mechanism of claim 8 wherein a portion of said feed table is depressed to permit the strip already in the feed table to descend to a lower level to space it below the incoming strip which is being moved across it.

11. The mechanism of claim 8 wherein a plurality of inclined steps are formed in said feed table and wherein spring members are positioned above said inclined steps to successively depress the trailing edge of each precedin; strip below the overlapping leading edge of the next succeeding strip to expose said trailing edge to said feed ngers to facilitate the longitudinal movement of said preceding strip along said feed table.

References Cited in the ile of this patent UNITED STATES PATENTS 2,375,989 Hale May 15, 1945