US2881438A - Apparatus for driving and clinching a two-prong fastener - Google Patents

Description

A. WINKLER ET AL 2,881,438 APPARATUS FOR DRIVING AND CLINCHING April 14-, 1959 A TWO-PRONG FASTENER v 4 Sheets-Sheet 1 Filed Aug. 1, 1956 April 14, 1959 A, 1.. WINKLER ET AL 2,831,438

APPARATUS FOR DRIVING AND CLINCHING A TWO-PRONG FASTENER Filed Aug. 1, 1956 4 Sheets-Sheet 2 A w- H zivmvrons n J g aslii OldJm/rm \m'uiwm' Pawn;

Aprll 14, 1959 A. L. WINKLER ET AL 2,881,438

APPARATUS FOR DRIVING AND CLINCHING A TWO-PRONG FASTENER Filed Aug. 1, 1956 4 Sheets-Sheet 5 F1. .b- 2&9 I 58 A M VENTORS 108 mu m 9 2mm April 14, 1959 A, 1.. WINKLER ET AL APPARATUS FOR DRIVING AND, CLINCHING A TWO-PRONG FASTENER Filed Aug. 1, 1956 4 Sheets-Sheet 4 1 .13 1 .14 1 1 .15, 59 {a (iNVENTORS United States Patent APPARATUS FOR DRIVING AND CLINCHING A TWO-PRONG FASTENER Alvin L. Winkler and Leslie J Oldham, Chicago, 11L, assignors to Auto Stapler Corporation, Chicago, 111., a corporation of Delaware Application August 1, 1956, Serial No. 601,457

8 Claims. (Cl. 1-3) This invention relates to the art of two prong paper fasteners and particularly to a machine for driving and clinching them.

The ordinary T-shaped two prong paper fastener, as widely used today, is designed especially for manual use, and there seem to be no such fasteners available on the market which are adapted or designed for use with a machine for driving and clinching them, nor any machines. It is the principal objectof this invention to provide a T- shaped two prong paper fastener with an improved shape adapting it for use with a machine for automatically driving and clinching it.

The usual T-shaped two prong fastener is ordinarily provided with its two prongs orlegs closely adjacent to each other, and even though spreading these prongs to clinch them after passing them through the paper sheets to be fastened together can be accomplished readily by hand by having one prong longer than the other, a problem arises in regard to spreading the prongs by mechanism associated with a machine for driving and clinching the fasteners. It is, therefore, another object of the invention to provide an improved fastener having an improved shaped head which, when squeezed, causes the fastener prongs to diverge or spread apart to especially adapt the fastener for use with a machine for automatically driving and clinching it by means of relatively simple mechanism.

It is still another object to provide an automatic machine for driving and clinching the improved fastener, which machine is initiated by the presence of the paper or material to be fastened and thereafter independently completes the job of driving and clinching the fastener.

The invention can be better understood by referring to the accompanying drawings, in which:

Figure 1 shows a side elevation of a preferred embodiment of the machine embodying the apparatus for driving and clinching the improved fastener;

Fig. 2 shows a left end view of the machine shown in Fig. 1;

Fig. 3 shows a right end view of the machine shown in Fig. 2; 1

Fig. 4 shows a simplified schematic wiring diagram of the electrical operating circuit of the machine;

Fig. 5 shows a preferred embodiment of the improved fastener used with this invention;

Fig. 6 shows a sectional view of'the machine as viewed along the line 66 of Fig.3 with'all of the operating parts in positions corresponding to the start of an operat ing cycle of the machine; I

Fig-7 is identical in cross-section to the view in Fig. 6 except that all parts are shown as they are positioned at the end of an operating stroke of the machine;

Fig. 8 shows a sectional view of the machine as viewed along line 8-8 of Fig. 6;

Fig. 9 shows a sectional view'similar to the views of Fig. 6 and Fig. 7 except that the operating parts are shown in intermediate positions .after driving of the fas- 2,881,438 Patented Apr. 14, 1959 2 tener has been completed but before spreading an clinching of the fastener legs has occurred;

Figs. 10 through 15 show schematically the entire operating sequence of all of the operations of the machine when it performs an entire operating cycle to drive and clinch a fastener;

Fig. 16 shows a sectional view along the line 16-16 of Fig. 6. v

The improved fastener 76 for use in the improved machine, as will be described, is shown particularly in Fig. 5 and consists of a head member 109 connected to two legs or prongs 110 and 111 which abut each other and-extend at right angles to the head 109. The lower ends 112 and 113 of these prongs are tapered to points to permit easy penetration of these prong through the work material and one of the ends 113 terminates short of the end 112. For use on the machine, it is not necessary that these legs be of difierent length, but it is preferred to manufacture them this way in order to permit manual separation of the prongs or legs with little difiiculty in cases where the fasteners are manually fastened. The machine, in most cases, would probably be used to provide the initial fastening of the first couple of sheets of paper which might be some form of stacked sheets to be circulated and the fasteners would be manually opened and closed to permit subtraction or addition of papers to the stack during subsequent handling of the papers.

The head member 109 of the fastener is provided with a single top piece 114 extending parallel to two lower pieces 115 and 116 spaced from the top pieces 114. The outer ends of the top piece 114 and the lower pieces 115 and 116 are connected by radius portions 117 and 118. The inner ends of the pieces 115 and 116 join to two members 119 and 120 which extend angularly upward toward each other and toward the top piece 114 where they terminate in contact with the top piece 114 and at corners 121 and 122 Where they connect to the upper ends 123 and 124 of legs 110 and 111. The advantage of this head member 109 is that, when the bottom pieces 115 and 116 are squeezed into proximity with the top piece 114, the angles 125 provided between the members 119, 120 and the top piece 114 decrease with the result that the legs 110 and 111 spread divergently about the corners 121 and 122 as approximate pivot points.

As shown in Figs. 1, 2 and 3, a preferred embodiment of the machine for driving and clinching the improved fasteners 76 comprises a rectangular base plate 1 provided with two vertically upright supports 2 and 3 mounted at the corners on one end of the 'base plate 1 and a somewhat larger vertical support 4 mounted closer to its other end. Positioned at the upper ends of the supports 2, 3 and 4 is a top plate 5.

The support 4 is provided with two legs 6 and 7 which extend for its entire length and are connected together by a web 8 for their upper half and spaced apart at their lower halves for a space equal to the width of the web 8. This web 8 provides two grooves 9 and 10 (Fig. 16) each provided with bottom Walls 11 and 12, respectively, and side walls 13, 14 and 15, 16, respectively. The clincher bar 17 is guided in the groove 9 while the driver bar 18 is guided in the groove 10. Retainer plates 19 are fastened by means of screws 20 to the support 4 and they overhang the groove 9 in order to retain the clincher bar 17 in position in the groove 9. Similarly, retainer plates 21 are provided on the opposite side of the support 4 and are held in place by means of screws 22. These retainer plates 21 overhang the groove 10 in order to retain the IQWQIZ end. of the linkv 2.6.. ispivoted on a. pin 28 to the outer end of a link 29 whose inner end is keyed to a shaft 30. The shaft 30 is mounted through a hole in a block 31 \vhichis fastened tothe inner face of the leg 6 of the support 4. The end of the shaft 30 opposite to that which is-tconnected to thelink 29 is provided with a sprocket 32., aspring; 33, and flange 34 and a circular cam 35, in that order. The sprocket 32 is provided with one end of a chain 36 wrapped on it for about three-quarters of its circumference and; engaged by the teeth of the sprocket 32. The other end of the chain 36 is connected by a pin-37 m the plunger 38 of a solenoid 39. The, solenoid 39 is: mounted on the base plate 1. The spring-33 is a coil spring with one end fastened to the shaft 30 by means of a pin 40.. Its other end-41 reacts against the upper surface of the. base plate 1. The spring is positioned so as totendto rotate the shaft 30 in clockwise direction as viewed in Fig. l. The cam is circular except for a detent; 42 at one small portion of its peripheral circumference.

A. switch 43 is mounted on the base plate 1 and pro vided with: av plunger fitted with a roller 44 which is always in contact with the periphery 44 of the cam 35. When the cam 35 is rotated to a point where the roller 45 drops into or out of the detent 42, the switch 43 is actuated.. Its operation will be discussed in more detail in connection with the entire electrical operation of the machine.

The clincher bar 17 is connected at its upper end to the lower end 46 of a C-shaped clincher arm 47 whose upper end.,.48. extends inwardly across the path of travel of the driver bar 18. Its. under surface 49 is its clinching surface. The end 48. is considerably wider than the rest of the-clincher arm 47 and extends beyond the inner edges of the two vertical support members 50 and 51.

The upper end 48 of this clincher arm 47 is provided with an aperture 52 having an inclined front inner surface 53.

The support members 50 and 51 are spaced apart from each other and fastened at their lower ends by means of screws 54 and 55 to the upper portion of the arms 6 and 7 of' the support 4. The upper ends of these support members. 50 and 51 are provided with inwardly extending lugs 56' which provide bearings for supporting the two ends of a shaft 57. The shaft 57 supports, atits midportion, anauxiliary. clincher 61 having a downwardly extending arm passing through the aperture 52. of the clincher arm 47 and consisting of a straight portion 53 connectedto a portion 59 extending angularly forward which in turn connects to another straight portion 60 whose lower end'terminates the auxiliary clincher 61. A-coil spring 61a is mounted concentrically with the shaft57 to urge the lower end of the auxiliary clincher 61 forward. The extreme lower endv of the portion 60-is provided with an angularly sloped back 62 for purposes ofclearance while its front surface is provided with two triangular shaped. and. pointed ends 63 and 64 having adjacent sides which extend divergently upward. The auxiliary clincher 61' is used during an intermediate step beforefinalclinching of the fastener prongs to act as a backing to permit initial spreading of the fastener prongs away from each other. This operation will be discussed inmore detail along with the discussion of the entire operation ofv the machine.

The clincher bar 17 is provided with two spaced lugs 85 projecting downwardly from beneath the clincher arm 47'. These lugs 85 support a pin 86 between them and the upper end 87 of an L-shaped link 88 is pivoted on the pin- 86. The lower end 89 of the link 88 is pivoted on apin'90 tothe outer'end of another link 91 whose inner end is keyed to the inner end of a shaft 92 which in turn is=trunnioned in a hole 93: passing through the leg 7 of the support '4." The outer end of the shaft 92 isprovided, in this-order; with a chain sprocket 94, a coilspring 95 mounted o na flanged hub 96 keyed to the shaft 92, and a circular cam 97 provided with a circular periphery 98 having a detent 99 (Fig. 6) This arrangement on the outer end of the shaft 92 isi similar to the arrangement of parts on the shaft 30 which is associated with the driver bar operating mechanism. The sprocket pinion 94 is provided with a chain 100 which is wrapped partially around the sprocket at its outer end and its inner end is secured to the plunger'101 of a solenoid 102. The spring 95 has oneend secured to a pin 103 mounted in a fixed position relative to the shaft 92. and its outer. end 104 reacts against the, upper surface of. the base plate 1. The effect of this spring arrangementisto tend to urge rotation of the shaft 92 in a counter-clockwise direction, as viewed in Fig; 1. Thecircular cam 97 is associated with a switch 105 which is provided with a roller 106 which is always in contact with the peripheral surface 98 of the cam 97. The switch 105 is actuated as the plunger either engages or disengages the detent 99 provided on the cam 97. V 7

As shown best in Figs. 6, 7, 8 and 9', a flat leaf spring 65 has. its rear end mounted on a crosspie'ce. 66and1it is held inplace, by means. of two screws 67 which fasten the end of the springto; thecrosspiece 66 by meansofa retainer plate 68.. A central portion of the spring isprovided with an aperture, 69 through whichthe clincher arm 47 passes. The forward end of the spring is provided with an inwardly extending slot 70 which is aligned with the path of travel of thefdriver bar 18 and, likewise,,the path of travel'of a fastener to be driven. When a fastener is drivenby the driverbar 18,, its two. closely positioned prongs pass through the slot 70'andthe spring is used as a guide to temporarily hold the fastener after itslegs. are spread, but before finalflclinching. It is also. used as a backingin caseseveral slieets. of paper to be fastened together provide too much cushion to permit adequate compression of the fastener head. The. slot 70of' thespring 65 is providedwith inwardly tapered sidewalls 70a ('Fig. 8) .which leadin the fastener subsequent to the one being driven as the spring drops back down after a fastening cycle has been completed.

As shown in Figs. 1 2, 3, 6, 7, 8 and 9, a fastener magazine 71 is fastened to the lower surface of the top plate. 5 by means of screws 72. which pass through: outwardly extending flanges 73 of'the magazine 71,. The magazine is provided with twovcrtical side walls 74 spaced-from each other sufficiently to provide anv opening for the. legs, of a fastener. These walls 74 connect at their lower ends to two laterally extending channels having upper and bottom Wall's spaced'from each-other sufficiently to permit the passage of the heads of the fasteners, The fasteners 76 are positioned abutting each other. in. acontinuous row, as shown in Figs. 6, 7, 8 and 9, within the magazine 71, andthe forward end 77of the plate 78 presses. against the outermost fastener to keep the fasteners closely positioned to each other. pl'a't'e78 is providedat its outer end with a pin 79 fastened'to the end of a long helical spring 84 whose forward portions are coiled about 'a'pin 82 with the leading'end of the spring securely fastened to the pin 82. Thepin 82 is mounted in a bracket 83 suspendedfr'om thelower portion of the magazine 71. The spring84'is used to cause the plate 78 to'be pressed forward against the outermost fastener as already described. V

Another switch-107'ismounted on the outer edge of the leg6 of the support 4'and'it is providedwith an outwardly extending arm 108 which projects abovethe upper level of the top plates. The switch 107is actuated b'y'movement'of this arm 108'. The arm 108 ismoved by-contact with. the leadi'ng edge of a paper or"pape'rs tobe fastened when the operator feeds the papers to the machine;

In Figs. 10 through 15 are shownthe sequential opv crating movements of the machine. Initially; a fastener 76 rests with; its. headz109xupon:v the: upper end 23 of the driver bar.18;'therfastener'having been supplied fromathe magazine 71. The legs of the fastener protrudeupwardlyi through slot 70 of the spring 65. Above the spring 65 are positioned the papers 126 which are to be fastened together. Above the papers are positioned the points 63 and 64 of the auxiliary clincher 61. Theupper end 48 of the clincher arm 47 is provided well above the tips 63 and 64 of the auxiliary clincher 61. As shown in Fig. 11, the first movement of the machine is the operation of the driver bar 18 which drives the fastener 76 upwardly so that its head deflects the front end of the spring 65 upwardly into contact with the paper through which passes its legs. The legs 110 and 111 end up positioned between the tips 63 and 64. Next, as shown in Fig. 12, the driver bar 18 continues upwardly to squeeze the head 109 of the fastener 76 against the lower surfaces of the tips 63 and 64. This decreases the angular relationship 125 of the portions 119 and 120, as already described relative to Fig. 5, with the result that the legs 110 and 111 spread angularly apart. As shown in Fig. 13, after the legs are spread in this manner, the upper end of the clincher arm 48 is moved downwardly so that its lower surface 49, contacts the fastener legs and causes them to be finally clinched as shown in Fig. 14. During the movement shown in Fig. 13, the auxiliary clincher 61 is cammed out of the path of the fastener by the clincher arm 47 as its wall 53 cams against the angular portion 59 of the auxiliary clincher 61. This camming action clears the path of the tips 63 and 64 for the upper end 48 of the clincher arm 47, so that it can complete the clinch, as shown in Fig. 14, to cause the fastener legs 110 and 111 to extend parallel to the head member 109. After clinching has been completed, the driver bar 18 and the clincher arm 48 are returned to their initial positions and the auxiliary clincher 61 again projects its ends 63 and 64 into the path of travel of a fastener because of its spring return. As shown in Fig. 15, the spring 65 is still positioned between the head of the fastener and the paper sheets. In order to remove the spring from the clinched fastener, it is mere- -1y necessary to pull the paper out of the machine. Note that the spring 65 is needed during the movement of the clincher arm 47 which is indicated by the movement of its upper end 48 in Fig. 13. At this time, since the auxiliary clincher 61 has been removed, without the spring 65 present there is the possibility that the fastener being clinched might become misaligned.

In order to acquire movement of the driver bar 18 for the purpose as described, the solenoid 102 is energized to cause its plunger 101 to pull the chain 100 to cause rotation of the 'shaft 30 with a resultant movement of the link 26 to cause the driver bar to raise vertically. Upon completion of the driver stroke and when it is necessary to return it to its initial position, the solenoid 102 is de-energized so that the spring 33 causes reverse rotation of the shaft 30 to return the link 26 andthe driver bar 18 to its initial position.

When it is desired to lower the clincher arm 47 for the purpose described, the solenoid 39 is energized to cause its plunger 38 to pull the chain 100 and cause rotation of the shaft'92 to cause the link 88 to lower and cause the clincher bar 17 to be lowered. At a time when the clincher bar 17 is again to be raised to its initial position, the solenoid 39 is de-energized and the spring 95 causes reverse rotation of the shaft 92 to return all parts.

As shown in Fig. 6, the parts are all positioned to correspond to the location of parts shown in Fig. at the beginning of a fastening operation. Fig. 9 represents the position of parts corresponding to the parts as shown in Fig. 11, while Fig. 7 shows the positions of parts corresponding to the positions shown in Fig. 14 at the completion of a driving and clinching operation. Note in Fig. 7 that the clincher arm 47 is retracted to a position where its clinching surface 49 is below the level of the lower surfaces of the tips 63 and 64. This happens because link 29 has rotated past center to cause slight retraction of the driver bar 18 to a position lower than that shown in Fig.

9 and the clincher arm 47 has lowered to the correspond- 'ing lower position of the driver bar 18. In Fig. 7, the

driver bar 18 is in a position of squeezing of the fastener head 109 to react against the tips 63 and 64 to cause divergence of the legs 110 and 111. The driver bar 18 is retracted as mentioned in order to relieve the squeezing force and permit the tips 63 and 64 to be easily retracted as the clinching arm 47 moves downwardly and earns against them. I

The electrical operation of the machine can be understood by referring to' the simplified electrical diagram shown in Fig. 4. The voltage is provided through a plug 133 between wires 134 and 135. These wires 134 and 135 are provided with two branch circuits. The first branch circuit consists of switch 107, relay switch 131 and the solenoid of relay 130 connected in series between wires 134 and 135. The second branch consists of switch 43, the solenoid 102, relay switch 132 and two poles 105a and 105b of the switch 105 connected in series between wires 134 and 135. An additional solenoid 39 is connected from one of these branch circuits to the other at points between switch 107 and relay switch 131, and solenoid 102 and relay switch 132. Another contact 1050 of the switch 105 connects between relay switch 131 and the solenoid of the relay 130.

Prior to the start of an operating cycle, voltage is supplied across the wires 134 and 135, all electrical parts are de-energized, and the parts are in the positions as shown in Figs. 1, 2, 3,4 and 10. The open switches are 43, 107 and 131. A closed switch is 132 and switch 105 has its contact 105a connected to its contact 105b. The solenoids39, 102 and that of relay 130 are all de-energized.

' When a paper or papers are inserted into the machine, the

paper contacts the arm 1080f the switch 107 to cause this switch 107 to close. This in turn energizes solenoid 39 by supplying electrical current through switch 107, the solenoid 39, closed switch 132 and the contacts 105a and 105b of the switch 105. With solenoid 39 energized, its plunger 38 is retracted to cause rotation of the shaft 30 with consequent upward driving of the driver bar 18 to cause the fastener to penetrate the paper and have its legs spread as the head 109 of the fastener is squeezed against the lower surfaces of the point ends 63 and 64 of the auxiliary clincher 61. At this time, as already mentioned, the end of the spring 65 is also raised up against the paper to act as a guide and retainer for the fastener. As also mentioned, it is also used as a backing especially helpful when several sheets of paper to be fastened together provide too much of a cushion to permit adequate compression of the head 108 of the fastener.

Immediately upon completion of the driving stroke, the cam 35 has rotated sufliciently so that the roller 44 of the switch 43 drops in the .detent 42 of the cam 35 and causes the switch 43 to close. At this time solenoid 102 is energized as current passes through the switch 43, the solenoid 102, the closed switch 132 and the contact 105a and 105b of the switch 105. Energizing switch 102 causes the plunger 101 to be retracted to cause the chain to rotate the shaft 92 and thereby lower the link 88 and the clincher bar 17. This causes the upper arm 48 of the clincher 47 to be lowered down against the paper and cause final clinching of the legs of the fastener. This action occurs by the motions indicated in Figs. 13 and 14. When clinching has been completed, cam 97 has been rotated to a point where the roller 106 of the switch falls into the detent 99 on the cam 97. This causes the switch 105 to change positions so that contact 105a breaks with contact 105b and connects with 1050. This causes energization of the solenoid of the relay 130. Energizing this solenoid causes its relay switches 131 and 132 to be alternately opened and closed. Switch 131 closes while switch 132 opens. Opening switch 132 causes de-energization of both solenoids 39 and 102 to permit return of the clincher bar 17, the driver bar 18 and all related parts because of the spring return 'actionof' thetwo spring's and 95'; Closing switch 131 merely keeps the solenoid of the relay- 130 energized at this time. when the-paper. is removedfrom the machine, switch 107 is'opened to de-energize the coil of the relay 130 to in turn cause closing of switch 132 and opening of switch 131. This leaves the machine in its initial electrical condition ready for a new cycle of operation.

Although one form of fastener and machine have been shown and described particularly, it' will-be obvious to persons skilled in the art thatother constructions and modifications are possible without departing from the true scope of the appended claims defining the invention.

We claim: 7

l. A machine for applying fastener of a type characterized by a head connected to the upper ends of two prongs which diverge when the .head is squeezed, comprising means for drivingthefastener through a work piece, means for squeezing the head to cause the two prongs to diverge, and means" for clinching the two prongs against the work piece.

2. A machine for applyin'g a fastener of a type having a head connected to two prongs; said head being provided with upper andlower bars, said lower bars having portions extending angularly toward each other to converge at a juncture with the upper ends of said prongs adjacent said upper bar, comprising means for driving the fastener head into contact with and squeezing it against an intermediate clincher to compress said' head and cause the angular'portion of said lower bars to flatten and the prongs to diverge.

3. A machine for applying a fastener of a type having a head connected to two prongs, comprisingmeans on one side of a work piece for driving the fastener to cause its two prongs to penetrate the work piece, com pression means on the opposite side of the work piece in the path of travelof the fastener bar compressing the fastener head, and meansfor bo'th deflecting said compression means out of the path of' travel of the fastener and for clinching the two fastener prongs.

4. A machine for applying a fastener of a type having a head connected to two prongs which diverge upon compression of the head, comprising means on one side of a work piece for driving the fastener to cause its two prongs to penetrate. the work piece, compression means on the opposite side of the work piece in the path of travel of the fastener for compressing the fastener head and causing divergence of 'saidprongs, and means for deflecting said compression meansclear of the path of travel of the fastener and'for'foldingthe prongs against the" workpiece. v c v 5. A machine: for applying'a fastener of a. type having a head connected to two prongs which diverge upon compression of the head, comprising a support for a piece to be fastened, a magazine attached to said support for holding a supply of fasteners for supplying fasteners to a driver reciprocably mounted on said support on one side of'saidworkpiece, said driver causing a fastener to be displaced from said magazine to cause 0 its prongs to penetrate said work piece, compression means on the opposite side of said work piece retractably mounted on said support in the path of travel of said fastener for compressing thev fastener head and thereby causing divergence of the: prongs of said fasteners, and a clincher arm reciprocably mounted on said support for deflecting said compression means clear of the path of travel of the fastener and for folding said prongs against the work piece.

6. A machine for applying a fastener of a type having a head connected to two prongs which diverge upon compression of the head, comprising a support for a work piece to be fastened, a magazine attached to said support for storing a supply of fasteners to be supplied one at a time to a driver reciprocably mounted on said support, said. driver adapted to drive a fastener supplied from said magazine to cause its two prongs to penetrate said' workpiece, compression means retractably mounted on said support and ordinarily biased to extend into the path of travel of said fastener being driven for compressing the fastener head and thereby causing divergence of said prongs, and a clincher arm reciprocably mounted on said support for retracting said compression means clear of the path of travel of the fastener being driven while the clincher arm travels to fold the fastener prongs against the work piece.

7. A machine for applying a fastener of a type characterized by a head connected to the upper ends of two prongs which diverge when the head is squeezed, comprisingmeans for driving the fastener prongs through a work piece, means to guide the prongs while they are driven, means for squeezing the head to cause the two prongs to diverge after they arediiven through the work piece, and means for clinching the two prongs against the work piece.

8. A machine for applying a fastener of a type characterized by a head connected to the upper ends of two prongs which diverge when the head is squeezed, comprising driving means for driving the fastener prongs through a work piece, retractable compression means for squeezing the head against the driving means to cause the two prongs to diverge after they are driven through the work piece, resilient means to both guide the prongs while they are driven and to support the fastener after the compression means is retracted, and means for clinching the two prongs against the work piece.

References Cited in the file of this patent UNITED STATES PATENTS Overman Dec. 1, 1908 1,365,408 Hutchison Jan. 11, 1921 1,444,290 Westby Feb. 6, 1923 1,910,955 Kohnle May 23, 1933 2,272,533 Svenson Feb. 10, 1942 2,296,493 Bernstein Sept.,22, 1942 2,420,660 Falter May 20, 1947 2,480,323 Derman Aug. 30, 1949 2,514,939 Crary July 11, 1950

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