US3642187A

US3642187A - Stitching head

Info

Publication number: US3642187A
Application number: US37190A
Authority: US
Inventors: Lauri C Barland
Original assignee: FLYNN AND EMRICH CO
Current assignee: Molins Machine Co Inc; FLYNN AND EMRICH CO
Priority date: 1970-05-14
Filing date: 1970-05-14
Publication date: 1972-02-15
Anticipated expiration: 1989-02-15

Abstract

A wire stitching head is disclosed for successively producing a series of uniformly shaped and sized stitches from a continuous length of wire and includes a reciprocating stitch-forming bar and a relatively shiftable stitch-driving bar operated by a single rotating cam wheel fitted with a first cam edge which coacts with a guide roller to feed a predetermined length of wire into stitch-forming position upon each rotation of the cam wheel. The cam wheel is further provided with a second cam surface which cooperates with a following rod to properly position a pivoting anvil into stitch-forming position during the stitch-forming operation. The guide roller is adjustable and is provided with a compressible inner core whereby the stitching head can accommodate different-dimensioned wire stock without the necessity of changing either the cam disc or the guide roller. Additionally, a dual directional clutch is utilized to selectively interconnect the output shaft of an electric motor with the driven shaft which carries the aforementioned cam wheel at one free end thereof, the opposite end of the driven shaft carrying means for actuating electrical switch contacts utilized to synchronize the operation of the stitching head in an overall stitching machine. Finally, a drag brake assembly which cooperates directly with the aforementioned cam wheel is employed to prevent override of the cam wheel when the clutch disengages to thereby directly prevent the cam wheel from unintentionally beginning another stitch-forming operation. Finally, by employing a solid, one-piece frame, it is possible to utilize interchangeable stitch-defining lower guide members whereby the size of the ultimately defined stitch can be easily varied.

Description

United States Patent Barland 1 Feb. 15, 1972 [54] STITCHING HEAD [72] Inventor: Lauri C. Barland, West Chester, Pa.

[73] Assignee: Flynn & Emrich Company, Baltimore,

[22] Filed: May 14, 1970 [21 Appl. No.: 31,190

[52] US. Cl ..227/84, 227/90 [51 Int. Cl ..B25c 5/04 [58] Field of Search ..227/82, 83, 84, 85, 86, 87,

Primary Examiner-Granville Y. Custer, Jr. Arromey-Lemer, David & Littenberg [57] ABSTRACT A wire stitching head is disclosed for successively producing a series of uniformly shaped and sized stitches from a continuous length of wire and includes a reciprocating stitch-forming bar and a relatively shiftable stitch-driving bar operated by a single rotating cam wheel fitted with a first cam edge which coacts with a guide roller to feed a predetermined length of wire into stitch-forming position upon each rotation of the cam wheel. The cam wheel is further provided with a second cam surface which cooperates with a following rod to properly position a pivoting anvil into stitch-forming position during the stitch-forming operation. The guide roller is adjustable and is provided with a compressible inner core whereby the stitching head can accommodate difi'erent-dimensioned wire stock without the necessity of changing either the cam disc or the guide roller. Additionally, a dual directional clutch is utilized to selectively interconnect the output shaft of an electric motor with the driven shaft which carries the aforementioned cam wheel at one free end thereof, the opposite end of the driven shaft carrying means for actuating electrical switch contacts utilized to synchronize the operation of the stitching head in an overall stitching machine. Finally, a drag brake assembly which cooperates directly with the aforementioned cam wheel is employed to prevent override of the cam wheel when the clutch disengages to thereby directly prevent the cam wheel from unintentionally beginning another stitchforming operation. Finally, by employing a solid, one-piece frame, it is possible to utilize interchangeable stitch-defining lower guide members whereby the size of the ultimately defined stitch can be easily varied.

24 Claims, 10 Drawing Figures PAIENIEBFEB 15 1972 3542.1 87

mm 1 OF 4 INVISN'IOR.

L AUR/ C. BA RLAND L ERNER, DAVID 8 LITTENBERG ATTORNEYS PATENTEDFEB 15 I972 MET 2 [IF 4 BACKGROUND OF THE INVENTION This invention relates to wire stitching heads, and more particularly to wire stitching heads capable of successively producing a series of uniformly shaped and sized stitches from a continuous length ofwire.

In the U5. Pat No. 2,554,691 issued May 29, 1951 to R. E. Zeruneith there is disclosed a wire stitching head of the general type to which the instant invention is directed. Thus the Zeruneith stitching head includes as the heart of its mechanism, a motor-driven cam wheel which performs a number of functions which may be briefly summarized as follows.

First, the cam wheel carries along its periphery an arcuate feeding cam which, together with a cooperating rolling surface, functions to intermittently feed preselected lengths of wire into the head upon each revolution of the cam disc. Secondly, the cam wheel pivotally carries on a forward surface thereof a pair of links one of which is pivotally connected to a reciprocating stitch-forming bar and the other of which is pivotally connected to a stitch-driving bar which functions to drive a stitch into the workpiece after the stitch has been formed by the aforementioned stitch-forming bar. Finally, the cam wheel carries a second cam surface which cooperates with a follower rod to urge a pivotally mounted anvil into the path of travel of the stitch-forming bar, which anvil cooperates with the forming bar to establish the desired U-shaped stitch.

This basic machine, although enjoying wide-spread popularity in the industry, has always had many problems which the instant invention has been designed to eliminate. For example, one such problem relates to the flexibility of the machine to accept wire stock of various dimensions. In the Zeruneith US. Pat. No. 2,554,691 this problem was handled by providing a spring-biased shoe arrangement to continually urge the aforementioned rolling surface toward the wire-feeding arcuate cam provided on the multifunction cam wheel and thereby allow the wire-feeding mechanism to accept different dimensioned wire. Unfortunately, and for a number of reasons, this system has proved unsatisfactory and prior to the instant invention, no simple, inexpensive technique has been found to permit the basic Zeruneith-type wire stitching apparatus to accept wire stock of widely varying dimensions.

Another problem inherent in the basic Zeruneith mechanism relates to the clutch mechanism utilized to selectively interconnect the output shaft of the motor with the basic driven shaft which carries the aforementioned multifunction cam wheel at one end thereof. Recent attempts to improve this clutch mechanism have lead to the employment of unidirectional clutches which has improved the speed and accuracy of the basic Zeruneith apparatus. However, such unidirectional clutches are relatively complex and expensive, when compared to conventional dual directional clutches; and furthermore, the antioverride mechanism customarily employed with such unidirectional clutches has not been truly effective to prevent the unintentional initiation of another stitch-forming operation after the clutch has been disengaged.

A further problem inherent in the basic Zeruneith mechanism relates to the difficulties of varying the size of the stitch ultimately formed by the stitching head. As will be further explained, the height or depth of the ultimately formed U-shaped stitch is a function of the width of a channelway provided in a lower guide member and within which the aforementioned stitch-forming bar reciprocates. In the Zeruneith type of prior art devices, this lower guide member has always been an important structural portion of the frame of the overall stitching head, thereby making it extremely difficult to remove. Thus, prior to the instant invention there has been no suggestion of removing and replacing the guide member with guide members having a different-dimensioned channelway.

SUMMARY OF THE INVENTION The instant invention is directed to a wire stitching head of the general arrangement discussed above, but is provided with significant improvements which have simply, inexpensively and effectively eliminated the aforedescribed problems inherent in the basic Zeruneith type of stitching head.

Specifically, to permit the basic Zeruneith type of stitching head to easily accommodate wire stock of different dimensions, the instant invention provides a guide roller in close proximity to the aforementioned arcuate feeding cam of the multifunction cam wheel, which guide roller is provided with a compressible inner core which, in a most simple and expeditious manner, permits the path of travel established between the guide roller and the cam wheel to enlarge or decrease in accordance with the dimensions of the wire stock being utilized in the stitching head. Further, and in accordance with the invention, the guide roller is easily adjustable when it is desired to set the head for a given range of wire stock dimensions.

Additionally, and with the aid of a drag brake arrangement which cooperates with the multifunction cam wheel, the instant inventor has been able to employ a conventional dual directional clutch to selectively interconnect the output shaft of the stitching head motor with the driven shaft, one end of which carries the aforementioned multifunction cam wheel and the opposite end of which is provided with means to actuate electrical switch contacts employed to synchronize the operation of the stitching head in an overall stitching machine. In addition to reducing the overall cost of the stitching head, the utilization of a dual directional clutch has been found to markedly increase the speed and accuracy of the stitching head of the instant invention.

In addition, the instant invention employs the aforenoted drag brake arrangement in direct association with the multifunction cam wheel to prevent override of the cam wheel (and thereby prevent the unintentional initiation of another stitching cycle) after the-clutch disengages. It has been found that employing the drag brake arrangement directly in conjunction with the cam wheel is a vast improvement over the prior art techniques of preventing override at the site of the clutch mechanism, since it eliminates inaccuracies in the stitching cycle which frequently occur in the prior art devices because of the normal looseness of play" associated with the mechanical train joining the clutch and thecam wheel, such looseness increasing in direct proportion to the age and frequency of use of the machine.

Finally, by employing a solid, one-piece, (preferably cast) frame to house the stitching mechanism, the instant inventor has been able to employ interchangeable guide members having differentdimensioned channelways which can thereby simply and easily produce stitches of preselected dimensions.

Accordingly, it is an object of the instant invention to provide a wire stitching head capable of successively producing a series of uniformly shaped and sized stitches from the continuous length of wire intermittently fed into the head.

Another object of the instant invention is to provide such a wire stitching head having significant improvements which simply, inexpensively and effectively eliminate many of the problems inherent in similar prior art stitching heads.

Yet another object of the instant invention is to provide such a wire stitching head which is provided with an improved wire-feeding assembly which permits the stitching head to easily accommodate wire stock of different diameters without making changes in the stitching head. i

Yet another object of the instant invention is to provide such a wire stitching head which is able to employ a dualdirectional clutch mechanism to interconnect the output shaft of the stitching head motor with a driven shaft carrying a multifunction cam wheel at one end thereof and means to actuate electrical switch contacts at its opposite end thereof.

Still another object of the instant invention is to provide such a wire stitching head which includes a brake shoe arrangement employed directly in conjunction with the aforementioned multifunction cam wheel to prevent override and thereby avoid incomplete and/or unintentional stitching cycles after clutch disengagement.

It is another object of the instant invention to provide a stitching head employing a solid, one-piece, (preferably cast) frame to house the stitching mechanism, therefore making it possible to employ interchangeable guide members having different-dimensioned channelways which can thereby simply and easily produce stitches of preselected dimensioned channelways which can thereby simply and easily produce stitches of preselected dimensions.

These and other objects of the instant invention will become readily apparent upon consideration of the following specification and drawings in which:

FIG. 1 is a front elevational view of the stitching head of the present invention with the front cover plate thereof substantially removed to show the operative parts of the mechanism;

FIG. 2 is a side elevational view of the stitching head of the present invention;

FIG. 3 is a view taken along the arrows lIIIII of FIG. 2;

FIG. 4 is a view taken along the arrows IV--IV of FIG. 2;

FIG. 5 is a view taken along the arrows V-V ofFIG. 2;

FIG. 6 illustrates the locking mechanism associated with the adjustable guide roller of the instant invention;

FIG. 7 is a perspective view of a portion of an alternative embodiment of the mechanism of the instant invention illustrating several features thereof;

FIG. 8 is a perspective view of a portion of the instant invention illustrating the interchangeable feature of the instant invention;

FIG. 9 is a rear perspective view of a portion of the mechanism illustrated in FIG. 7; and

FIG. 10 is a perspective view of a portion of a front surface 18 of frame 16 of the instant invention.

Turning to the Figures, wherein like numerals are employed to designate like elements, it will be observed from FIGS. 1 and 2 that the wire stitching head 10 of the present invention is in the form of a compact motor driven organization which is adapted to be suitably mounted at the upper end of a main support or frame (not shown) which is provided with a horizontally disposed work-supporting surface 12 fitted with a clinching member or die 14 for clinching the wire stitches as the same are successively formed in the stitching head 10 and driven thereby through the work W to be stitched.

As mentioned previously, the instant invention is broadly similar to the stitching head of the aforementioned Zeruneith U.S. Pat. No. 2,554,691, and as such includes: top and bottom channeled

guide members

28 and 30 secured on the front surface 18 of a frame 16 for guiding a reciprocating stitch-forming bar 32 which has a bifurcated lower end 34, a driving bar 36 mounted for reciprocal motion within guideways 38 provided on the confronting inner surfaces 39 of the bifurcated lower end 34 of the forming bar 32; a multifunction cam wheel 40 rigidly secured to one end 42 of the driven shaft 44 suitably journaled by

ball bearings

46 and 48 in the front and rear surfaces 18 and of the frame 16; an electric motor 50 the output shaft 52 of which is selectively connectable to the driven shaft 44 by a clutch mechanism 54; and a pivoting anvil 56 the nose portion 58 of which is utilized in the stitch-forming operation in a manner to be briefly summarized below.

In order to understand the manner in which the improve ments of the instant invention function in a wire stitching machine of the type generally discussed above, it is perhaps worthwhile to begin the description of the instant invention by providing a short description of the overall operation of a basic Zeruneith type of stitching head.

Initially, it should be pointed out that .the cam wheel 40 carries an arcuate feeding cam 60 which projects slightly into the path of travel 62 defined by the periphery of the cam wheel 40 and a guide roller 64 the specific construction of which forms a part of the instant invention and will be subsequently described in greater detail. Thus, for each revolution of the cam wheel 40 (affected when the clutch 54 interconnects the continuously rotating output shaft 52 of the motor 50 with the driven shaft 44), a preselected length of wire, corresponding to the arcuate length of the feeding cam 60 will be advanced from a supply reel (not shown) through tubular wire guides 68, 70, and a passageway 72 provided in the lower channel casting 30, into channelway 74 provided in the lower channel casting 30.

It will be appreciated that the clearance between the guide roller 64 and the periphery of the cam wheel 40 is such that the wire 66 fits freely therebetween under normal circumstances. It is only when the projecting feed cam 60 enters the path of travel 62 that the wire is sandwiched" and thereby advanced. Secondly, it will be appreciated that the arcuate or peripheral length of the feeding cam 60 is preselectively chosen to correspond to the overall length of the ultimately desired staple.

Provided on the rearward side of the feed wheel 40 (as viewed in FIG. 1) is a second cam surface 76 which, as best seen in FIG. 2, cooperates with a following rod 78 to maintain the pivotally mounted anvil 56 in the wire supporting position illustrated in FIG. 2. It will be appreciated, that when the cam 76 rotates free of the following rod 78, a spring biased plunger 80 will rotate the anvil 56 in a clockwise direction (as viewed in FIG. 2) and out of the path of travel of the driver bar 36 as will be described below. It should be pointed out, that the placement of the earns 60 and 76 relative to one another, and the arcuate length of the cam 76, are chosen such that the anvil 56 and its wire supporting nose 58, will be in the proper wire-supporting position illustrated in FIG. 2, as the wire 66 is being advanced into the channelway 74 in the manner previously described.

Finally, the front surface 82 of the cam wheel 40 carries an outstanding pin 84 to which is pivotally connected one end of a pair of

links

86 and 88 respectively. The opposite end of the link 86 is pivotally connected to pin 90 outstanding from the former bar 32, and the opposite end of the link 88 is pivotally connected to a pin 92 provided on the driver bar 36. It will be noted that the pin 90 joining the link 86 to the former bar 32 is mounted off center and to the right (as viewed in FIG. 1) with respect to the location of the pin 92 which joins the link 88 to the driving bar 36. This mounting is intentionally chosen, as explained in the Zeruneith patent, such that the length of the reciprocating stroke of the driver bar 36 is greater than the length of the reciprocating stroke of the bifurcated forming bar 32 which together function in the following manner.

Assuming that the feeding cam 60 has positioned the next length of wire in the channelway 74 (appropriately supported by the anvil 56 by virtue of the cam surface 76 and the fol lower rod 78), continued rotation of the cam wheel 40 causes the

links

86 and 88 to begin the downward strokes of the former bar 32 and the driver bar 36 respectively. Because the lower end of the former bar 32 is initially much lower than the bottom edge 94 of the driving bar 36, the wedgelike surfaces 96 of the bifurcated end 34 of the former bar 32 quickly engage the opposite ends of the wire length positioned in the channel 74 and bend them downward around anvil nose 58 to form the desired U-shape stitch illustrated at 98 in FIG. 2. Immediately thereafter, the lower end 94 of the driving bar 36 reaches the bight portion of the U-shaped stitch and continues to drive the stitch (within the confines of the confronting faces 39 of the bifurcated forming bar) through the workpiece W and into engagement with the clinching member 14. It-should be pointed out, that the wire is initially cut from the c ntinuous supply running through the passageway 72 by the side edge 100 of the bifurcated forming bar 32. Additionally, it should be pointed out, that the positioning and length of the second cam surface 76 provided on the cam wheel 40 is such that just as the driving bar 36 engages the bight portion of the U-shaped stitch, the cam 76 leaves the follower rod 78 and the spring-biased plunger 80 quickly rotates the anvil 56 out of the path of travel of the driving bar 36.

Thus the stitch is fed, formed, driven and clinched in one quick and continuous operation, all motions of which are generated by the single multifunction cam wheel 40. During the second half-cycle of cam whee] rotation, the motions are reversed with the driving bar 36 being lifted before the forming bar 32. For a further detailed description of the stitch feeding, forming and driving operation, reference is made to the aforementioned Zeruneith US. Pat No. 2,554,691.

Turning to the specific contributions of the instant invention, it will be seen in FIG. 2 that the guide roller 64 is mounted for rotation on the reduced end 102 of a shaft 104 provided in the front face 18 of the frame 16. The guide roller 64 includes an outer cover member 106, an inner bearing cylinder 108 and a compressible inner core 110 of rubber or similar compressible material concentrically disposed between the

members

106 and 108 when the core 110 is in its natural or relaxed state. A pair of washers 112 maintains the core 110 within the outer cover 106 and a pair of retaining rings 114 are employed to retain the guide roller in its assembled condition.

With reference to FIG. 1, it should be noted that the outside diameter of the guide roller 64 is initially chosen (with the inner core 110 thereof in a relaxed state) such that the path of travel 62 established between the guide roller 64 and the periphery of the cam wheel 40 is slightly larger than the smallest wire stock which is to be used in conjunction with the stitching head 10. Thus, and as was explained previously, each time the cam wheel 40 experiences a revolution, the arcuate feeding cam 60 together with the guide roller 64 will sandwich and advance the wire 66. However, and in accordance with one aspect of the instant invention, should it be necessary to slightly increase the thickness of the wire stock being utilized in the stitching head 10, the compressible inner core 110 of the guide roller 64 permits the path of travel 62 to automatically increase in direct proportion to increasing wire thickness. This can be understood by visualizing the guide roller 64 rotating in a nonconcentric fashion with respect to the shaft termination 102 in response to the larger dimensioned wire passing through the path of travel 62. Thus with this extremely simple and inexpensive innovation, the head of the instant invention can easily accommodate wire stock of different dimensions without any changes being made on the head itself.

To permit the wire-feeding mechanism to accept wire stock of a greater range of thickness, the initial relaxed position of the guide roller 64 may be easily varied with respect to the periphery of the cam wheel 40. Specifically, and as best seen in FIGS. 2 and 6, the reduced end 102 of the shaft 104 is situated off center with respect to the center line of the main portion of the shaft 104. Therefore, by rotating the shaft 104 by means of a handle 105, the reduced end 102 can be raised or lowered with respect to the cam wheel 40. This adjustment capability may be thought of as establishing a coarse adjustment with the compressible nature of the inner core 110 establishing a fine" adjustment for various wire thicknesses within the given range established by the adjustment feature.

To maintain the shaft 104 locked in a preselected position, and as best illustrated in FIG. 6, the front surface 18 of the frame 16 is provided with a transversely oriented passageway 107 within which is slidably positioned a cylindrical rod 109 provided with a cutout portion 111 slightly nonconcentric with respect to the outer surface ofthe shaft 104. One end 1 13 of the rod 109 has a threaded bolt portion 115 threadably passing through a fixed nut 117. When the bolt portion 115 is rotated in one direction, the cylindrical rod 109 is longitudinally moved to free the shaft 104 for rotation. When the bolt 115 is rotated in the opposite direction the cylindrical rod 109 reverses its travel and engages and frictionally locks the shaft 104 in its preselected angular position.

Returning now to FIGS. 2 and 4, and to a consideration of another improvement of the instant invention, as noted previously, the clutch 54 hereof is a dual directional clutch and includes an outer member 116 freely rotatable on the driven shaft 44 and connected through meshing

gears

118 and 120 to the output shaft 52 of the electric motor 50. Thus the outer member 116 of the clutch 54 is continually rotating whenever the motor 50 is energized.

The clutch 54 further includes an inner member 122 which is keyed at 124 to the driven shaft 44 for rotation therewith. The inner member 122 includes a plurality of flat, chordal cam surfaces 126 so established that the dimension D in F IG. 4 is greater than the diameter of roller pins 128 disposed between the inner and outer members of the clutch. It should be pointed out that an annular cage 130 provided with appropriate openings 132 maintain the roller pins 128 in the above described first position in which the roller pins 128 are free to float or rotate about their own axis as the outer member 116 is rotating. Thus when the roller pins 128 are in their freely floating first position, the rotation of the outer member 116 of the clutch 54 will not be imparted to the inner member 122 and the clutch is disengaged.

By means to be presently described, the cage member 130 is rotatable within the outer member 116 to move the roller pins 128 to a second, wedging position (illustrated in phantom at 128' in FIG. 4) wherein the dimension D between the inner member 122 and the outer member 116 is less than the diameter of the roller pins 128. When the roller pins reach their second wedging position, it will be apparent that the rotation of the outer member 116 will then be imparted to the inner member 122 of the clutch 54 to thereby rotate the driven shaft 44 and the cam wheel 40 to initiate a stitch advance form and drive operation as explained previously. After a predetermined number of revolutions of the inner member 122 (corresponding to the desired number of stitches), means to be presently described return the cage 130 to its initial position (relative to the inner and outer members) and the roller pins to their first, freely floating position to thereby disengage the clutch.

The means for engaging and disengaging the clutch are best illustrated in FIG. 3. Specifically, it will be seen that a biasing spring 134 continually urges the cage 130 in a counterclockwise direction. In the absence of a trip pawl 136, the spring 134 would normally bias the cage 130 and the roller pins 128 to their clutch engaging position in which the roller pins 128 are wedged between the inner and outer members of the clutch. The trip pawl 136 is pivotally mounted on the frame at 138 and biased by a torsional spring 140 to the position shown in FIG. 3 in which one end 142 thereof is in blocking relationship with respect to a trip pin 143 secured on the front surface of the cage 130. With the trip pawl 136 in its blocking position, the cage 130 is maintained against the bias of spring 134 in its first position in which the clutch is disengaged because the roller pins 128 are freely floating between the outer and inner members of the clutch.

The opposite end 144 of the trip pawl 136 is connected to the armature 146 of a solenoid 148. When the solenoid is energized, the trip pawl 136 rotates counterclockwise about its pivot 138 and out of the path of the trip pin 143 whereby the cage 130 is free under the influence of the biasing spring 134 to move the roller pins 128 to their clutch engagement position. It will be appreciated that by timing means (not shown), the solenoid remains energized for a period of time corresponding to the direct number of stitches.

When the solenoid is deenergized, the torsional spring 140 returns the trip pawl 136 to its blocking position, a stop 150 being provided to redefine the blocking position.

Thus the trip pin 143, the cage 130, the pins 128 and the inner and

outer members

116 and 122 of the clutch 54 will experience complete revolutions in unison (and stitches will be fed, formed, driven and clinched), until such time as thd solenoid is deenergized and the trip pin 143 comes around and engages the end 142 of the repositioned trip pawl 136 to thereby halt the rotation of the cage 130 and the roller pins 128 carried thereby. It should be pointed out that the impact between the trip pin 143 and the trip pawl 136 is sufficient to displace the roller pins 128 from their wedging position 128 and thereby disengage the clutch.

Once the disengagement takes place, the outer member 1 16 of the clutch 54 is again free to continuously rotate by itself, with the roller pins 128 rotating freely once again about their own axis. However, it will be appreciated that the inner member 122 (secured to the driven shaft 44 and in turn to the cam wheel 40) develops substantial momentum even during a single revolution; and when the clutch is disengaged, there is a tendency for the inner member 122 to continue to rotate and unintentionally and inadvertently begin the next stitching cycle. This clutch override problem has always been especially acute in situations where designs engineers have attempted to utilize dual directional clutches, and has perhaps been the primary reason why, prior to the instant invention, designers have been unsuccessful in their attempts to utilize such dual directional clutches in this type of stitching head.

Specifically, and with reference to FIG. 4, assume that the roller pins 128 had been moved to their phantom positions 128' to initiate revolutions of the clutch and a staple feeding, forming, and driving operations. After the completion of the desired number of revolutions, and as explained previously, the trip pin 143 on the face of the cage 130 abuts the trip pawl 136 and in terms of relative movement, returns the roller pins 128 toward their freely floating center positions illustrated in solid line in FIG. 4. However, because the clutch 54 is dual directional (that is the cam surface 126 is chordal and the pins 128 can be wedged if they be rotated in either direction), the continued rotation after clutch disengagement of the inner member 122, can end up producing a wedging action of the roller pins 128 at the point illustrated at 152 in FIG. 4. This accidental wedging which can occur in a dual directional clutch creates two problems in the sense that (I) sometimes on the next cycle of operation the relatively small bias established by the spring 134 of FIG.'3 is insufficient to unjam the accidental wedging and (2) even if the spring 134 manages to disengage this unintentional wedge, there is a relatively large arc of roller pin travel required before the roller pin 128 reaches the intended wedging position 128. Since the above-described situation may occur inconsistently, the end result is inaccurately positioned stitches such that prior to the instant invention, it has not been possible to satisfactorily employ dual directional clutches of the type illustrated in FIG. 4.

However, the instant inventor has eliminated all of the aforedescribed problems previously inherent in the utilization of dual directional clutch mechanisms by providing an antioverride drag brake arrangement broadly designated 154 in FIG. 5 (not shown in other Figures for sake of drawing clarity) to directly engage the cam wheel 40 and thereby prevents override when the clutch 54 is disengaged. With reference to FIG. 5, it will be seen that the drag brake means includes a brake shoe 156 the arcuate end 158- of which is biasingly urged into frictional engagement with the periphery of the cam wheel 40. To this end the opposite end 160 of the brake shoe 156 is pivotally secured to a pivotally mounted lever 162 which in turn is biased in a counterclockwise direction as viewed in FIG. 5 by a plunger 164 under the influence of a compression spring 166.

It will be appreciated that at the instant of clutch disengagement, the drag brake arrangement will prevent override of the cam wheel. It is to be further appreciated and contrasted to prior art devices, that the antioverride drag brake arrangement is utilized in direct conjunction with the feed wheel 40 rather than at the site of the clutch. Thus, and although the mechanical linkage between the clutch 54 and the cam wheel 40 may suffer from a looseness or play" which becomes exaggerated as the machine ages; the direct association of the drag brake with the cam wheel always maintains the desired stitch accuracy.

With reference to FIGS. 2 and 7 through 10, there is illustrated the manner in which the instant inventor has been able to make possible the use of interchangeable guideways which thereby permit the manufacture of difierent size stitches to be ultimately produced. Specifically, it can be seen in FIG. 2 that with the exception of the cover (not shown) the frame 16 is an integral one-piece member, preferably cast, which in of itself is solid enough to form a base upon which lower guide members such as 30 can be structurally supported. This is to be contrasted with the multimember frame constructions of the prior art which required the lower guide member 30 to function as a structural element of the frame.

Thus in FIG. 7 there is illustrated a lower guide member 30 which, in a manner to be further described, can be keyed to the front surface 18 of the frame 16 and, by bolt passageways 119, removably secured thereto. It will be appreciated in FIG. 7 that the channelway 74 is of a dimension d, which thereby produces a length of wire 121 of the same length d, which ultimately produces the stitch 98 having a height or depth dimension 123. i

In FIG. 8 is illustrated a lower guide member 30' which is of the same overall size as the guide member 30 but which is provided with a channelway 74' and a dimension d which ultimately produces a stitch 98 of a greater depth or height dimension 125. It will be appreciated that the bolt passageway 119' of FIG. 8 are spaced apart by the same distance as the bolt passageway 119 of FIG. 7 such that, with relative ease, the guide member 30 can be substituted for the guide member 30 of FIG. 7.

It will be appreciated that when employing a larger channeled guide way such as 30, the lower bifurcated end of the stitch-forming bar 34 must similarly be replaced with a bifurcated end of greater width. Thus in FIG. 8, the bifurcated end 34 corresponds in width to the dimension d for the channelway 74' whereas in FIG. 7 the overall width of the bifurcated lower end 34 corresponds to the dimension d, for the channelway 74.

When securing the various guide members such as 30 and 30, it is of course essential that they be properly aligned on the front surface 18 of the frame 16. To effect this alignment, and as best seen in FIG. 9, the rear surface 127 of all of the various guide members such as 30 and 30 are provided with rearwardly extending keying extensions 129' which are received in a keyway 131 (FIG. 10) provided in the front surface 18 of the frame 16. It will be appreciated that this keyway arrangement helps withstand the shearing forces normally generated by the reciprocating, forming and driving bars. Finally, to establish the necessary alignment, a forwardly extending projection 133 provided on the front surface 18 of the frame 16 fits within a cutout space 135 established between the extensions 129.

Thus by simply removing two bolts indicated at 137 in FIG. 1, various preselected guide members such as 30 and 30 can be employed to change the size of the ultimately produced stitch.

Finally, FIG. 8 illustrates two further features of the instant invention. First, an angular surface fillet 139 is provided in the guide member such as 30 and 30' and within which fillet 139 is positioned the previously mentioned passageway 72 by which the wire is fed into the channelway. The angular fillet causes the end of the wire to be cut'as illustrated at 141 in FIG. 8 thereby providing the pointed stitches such as illustrated at 98 with pointed terminations 143.

Finally, at 145 there is illustrated a carbide insert which functions as the shearing surface for cutting the wire lengths as the forming bar moves in its downward stroke.

Finally, and with reference to FIG. 2, the opposite end 168 of the driven shaft 44 carries an enlargement 170 provided with a flat cam face 172. As the driven shaft 44 completes a revolution, the flat cam surface 172 cooperates with electrical switch means or contact points broadly designated 174 mounted on an insulating plate 176. The switch means 174 can be a conventional, normally open or normally closed electrical switch and is preferably utilized to synchronize the operation of the stitching head 10 in an overall stitching machine, not shown.

Although this invention has been described with respect to its preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred, therefore, that the scope of the invention be limited, not by the specific disclosure herein, only by the appended claims.

Iclaim:

l. A wire stitching head comprising:

a frame;

stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length ofwire which has been supplied thereto;

stitch-driving means movably mounted with respect to said stitch forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head;

wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of said wire;

said wire-feeding means including;

a cam wheel mounted on said frame;

driving means for selectively rotating said cam wheel;

a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said continuous supply of wire therebetween;

said cam wheel having an arcuate feeding cam of said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means;

said guide roller having an outer cover member and a relatively compressible inner core whereby said path of travel can accept wire of preselected various dimensions without changing the diameter of either said cam wheel or said guide roller;

wherein said frame includes a guide roller supporting shaft extending therefrom;

wherein said guide roller supporting shaft includes a main portion rotatably mounted in said frame and an extending end portion eccentrically located with respect to said main portion;

said end portion having said guide roller freely rotatable thereon; and

whereby rotation ofsaid guide roller supporting shaft causes said guide roller to be moved with respect to said cam wheel.

2. The wire stitching head of claim 1 said guide roller having an inner bearing cylinder freely rotatable on said shaft, said compressible core being of cylindrical shape and being disposed in concentric fashion with respect to said bearing cylinder and said outer cover member when said core is in its relaxed state.

3. The wire stitching head of claim 2 and further including:

a pair of washers disposed on said bearing cylinder on opposite sides of said compressible core, said washers having an outer diameter greater than the inner diameter of said outer cover; and

a pair of retaining rings secured on said bearing cylinder on opposite sides of said washers respectively.

4. The wire stitching head of claim 1 and further including linking means connected between said cam wheel and said stitch-forming means and said stitch-driving means for operating said stitch-forming means and said stitch-driving means in response to rotation of said cam wheel by said driving means.

5. The wire stitching head of claim 1 wherein said driving means includes:

a driven shaft freely rotatable in said frame, said driven shaft having said cam wheel secured thereto at one end thereof;

motive means; and

clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft.

6. A wire stitching head comprising:

a frame;

stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length of wire which has been supplied thereto;

stitch-driving means movably mounted with respect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head;

said wire-feeding means including:

a cam wheel mounted on said frame;

driving means for selectively rotating said cam wheel;

said guide roller having an outer cover member and relatively compressible inner core whereby said path of travel can accept wire of preselected various dimensions without changing the diameter of either said cam wheel or said guide roller;

wherein said driving means includes:

motive means;

clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft; and

further including drag brake means mounted on said frame and biasingly urged into frictional engagement with said cam wheel for preventing override of said cam wheel when said clutch means is disengaged.

7. The wire stitching machine of claim 6 wherein said drag brake means includes:

means includes a dual-directional clutch.

9. A wire stitching head comprising:

a frame;

stitch-driving means movably mounted with respect to said stitch-forming means for driving the stitch formed by said stitch forming means into a workpiece positioned in predetermined relationship with respect to said stitching head;

said wire-feeding means including;

a cam wheel mounted on said frame;

driving means for selectively rotating said cam wheel;

a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means;

wherein said driving means includes:

motive means;

clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft;

further including drag brake means mounted on said frame and biasingly urged into frictional engagement with said cam wheel for preventing override of said cam wheel when said clutch means is disengaged;

wherein said clutch means includes a dual-directional clutch; and

wherein said dual-directional clutch comprises:

an outer member operatively connected to said motive means for rotation in response to energization thereof; an inner member keyed to said driven shaft for rotation therewith;

said inner member having at least one cammed outer surface;

a roller pin disposed intermediate said cammed outer surface and said outer member, said roller pin movable between a first position wherein said roller pin is freely floating between said cammed outer surface and said outer member and said outer member is free to rotate with respect to said inner member, and a second position wherein said roller pin is wedged between said cammed outer surface and said outer member and said inner member is thereby caused to rotate with said outer member; and

movable cage means disposed between said inner member and said outer member for moving said roller pin between its first and second position.

10. The stitching head of claim 9 wherein said movable cage means is normally biased to maintain said roller pin in its second position; and

further including trip pawl means mounted on said frame and movable between a first clutch disengage position which maintains said cage means in position to maintain said roller pin in its first position, and a second clutch engage position which permits said cage means to move said roller pin to its second wedging position.

11. A wire stitching head comprising:

stitch-driving means movably mounted with respect to said stitch forming means for driving the stitch formed by said stitch forming means into a workpiece positioned in predetermined relationship with respect to said stitching head;

wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of wire;

said wire-feeding means including:

a cam wheel mounted on said frame; driving means for selectively rotating said cam wheel;

wherein said clutch means includes a dual-directional clutch; and

wherein said dual-directional clutch comprises:

an outer member operatively connected to said motive means for rotation in response to energization thereof;

an inner member keyed to said driven shaft for rotation therewith;

said inner member having at least one cammed outer surface;

a roller pin disposed intermediate said cammed outer surface and said outer member, said roller pin movable between a first position wherein said roller pin is freely floating between said cammed outer surface and said outer member and said outer member is free to rotate with respect to said inner member, and a second posi tion wherein said roller pin is wedged between said cammed outer surface and said outer member and said inner member is thereby caused to rotate with said outer member; and

12. A wire stitching head comprising:

a frame;

stitch-driving means movably mounted withrespect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; and

said wire-feeding means including:

a cam wheel mounted on said frame; 1

driving means for selectively rotating said cam wheel;

wherein said driving means includes;

motive means; and

further including drag brake means mounted on said frame and biasingly urged into frictional engagement with said cam wheel for preventing override of said cam wheel whensaid clutch means is disengaged.

13. The wire stitching head of claim 12 and further including linking means connected between said cam wheel and said stitch-forming means and said stitch-driving means for operating said stitch-forming means and said stitch-driving means in response to rotation of said cam wheel by said driving means.

14. The wire stitching head of claim 12 wherein said drag brake means includes:

a drag brake lever pivotally mounted on said frame;

a brake shoe having one end pivotally connected to one end of said lever and its other end arcuately shaped to conform to the periphery of said cam wheel; and biasing means disposed between said lever and said frame for urging said other end of said shoe into frictional engagement with said periphery of said cam wheel.

15. The wire stitching head of claim 12 wherein said clutch means includes a dual directional clutch.

16. A wire stitching head comprising:

a frame;

wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply ofwire;

said wire-feeding means including:

a cam wheel mounted on said frame;

driving means for selectively rotating said cam wheel;

wherein said driving means includes:

motive means;

wherein said clutch means includes a dual directional clutch;

wherein said dual-directional clutch comprises:

an inner member keyed to said driven shaft for rotation therewith;

said inner member having at least one cammed outer surface;

movable cam means disposed between said inner member and said outer member for moving said roller pin between its first and second position.

17. The wire stitching head of claim 1 and further including locking means for maintaining said guide roller supporting shaft in a preselected angular position.

18. The wire stitching head of claim 17 wherein said locking means comprises:

a bore in said frame transversely oriented with respect to said guide roller supporting shaft;

a locking rod slidably positioned in said bore, said locking rod having an arcuate notch of slightly larger radius than said main portion of said guide roller supporting shaft;

said arcuate notch receiving said main portion of said guide roller; and

means for selectively engaging the inner surface of said notch with the outer surface of said main portion of said guide roller supporting shaft.

19. A wire stitching head comprising;

a frame;

a lower guide member removably secured to said frame,

said lower guide member having a channelway of predetermined width thereon; stitch-forming means removably mounted on said frame in reciprocating relationship with respect to said channelway for forming a preselectively shaped and dimensioned stitch from a preselected length of wire which has been supplied thereto;

stitch-driving means reciprocally mounted with respect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head;

wire feed means for intermittently supplying said preselected length of wire to said stitch-forming means from a supply of said wire;

whereby said lower guide member can be removed from said frame and replaced with various other lower guide members having channelways of predetermined differing widths which together with appropriately differing stitchforming means can produce stitches of various dimensions.

20. The wire stitching head of claim 19 wherein said frame is a one piece, integral member.

21. The wire stitching head of claim 19 wherein said channelway is provided with an angled surface at one end thereof; said guideway including a wire passageway through which said wire is advanced by said wire feed means into operative position with respect to said stitch-forming means and stitch-driving means; one end of said wire passageway terminating in the plane of said angled surface to thereby produce an angled cut of said wire when said stitch-forming means reciprocates in said channelway.

22. A wire stitching head comprising:

a frame;

a lower guide member removably secured to said frame, said lower guide member having a channelway of predetermined width thereon;

stitch-forming means removably mounted on said frame in reciprocating relationship with respect to said channelway for forming a preselectively shaped and dimensioned stitch from a preselected length of wire which has been supplied thereto;

whereby said lower guide member can be removed from said frame and replaced with various other lower guide members having channelways of predetermined differing widths which together with appropriately differing stitchforming means can produce stitches of various dimen sions;

wherein said frame includes a front face provided with a recessed slot; and

said lower guide member has a rear surface from which is projecting rearwardly extending keying means;

said keying means being removably received within said recessed slot.

23. The wire stitching head of claim 22 wherein said recessed slot is provided with an aligning projection and said keying means includes an aligning space which receives said aligning projection.

24. The wire stitching head of claim 21 wherein said lower guide member has secured thereto a hardened steel cutting element, said cutting element being secured to said guide member below said wire passageway.

Claims

1. A wire stitching head comprising: a frame; stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length of wire which has been supplied thereto; stitch-driving means movably mounted with respect to said stitch forming means for driving the stitch formed by said stitchforming means into a workpiece positioned in predetermined relationship with respect to said stitching head; wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of said wire; said wire-feeding means including; a cam wheel mounted on said frame; driving means for selectively rotating said cam wheel; a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said continuous supply of wire therebetween; said cam wheel having an arcuate feeding cam of said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means; said guide roller having an outer cover member and a relatively compressible inner core whereby said path of travel can accept wire of preselected various dimensions without changing the diameter of either said cam wheel or said guide roller; wherein said frame includes a guide roller supporting shaft extending therefrom; wherein said guide roller supporting shaft includes a main portion rotatably mounted in said frame and an extending end portion eccentrically located with respect to said main portion; said end portion having said guide roller freely rotatable thereon; and whereby rotation of said guide roller supporting shaft causes said guide roller to be moved with respect to said cam wheel.

3. The wire stitching head of claim 2 and further including: a pair of washers disposed on said bearing cylinder on opposite sides of said compressible core, said washers having an outer diameter greater than the inner diameter of said outer cover; and a pair of retaining rings secured on said bearing cylinder on opposite sides of said washers respectively.

5. The wire stitching head of claim 1 wherein said driving means includes: a driven shaft freely rotatable in said frame, said driven shaft having said cam wheel secured thereto at one end thereof; motive means; and clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft.

6. A wire stitching head comprising: a frame; stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length of wire which has been supplied thereto; stitch-driving means movably mounted with respect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of said wire; said wire-feeding means including: a cam wheel mounted on said frame; driving means for selectively rotating said cam wheel; a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said continuous supply of wire therebetween; said cam wheel having an arcuate feeding cam of said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means; said guide roller having an outer cover member and relatively compressible inner core whereby said path of travel can accept wire of preselected various dimensions without changing the diameter of either said cam wheel or said guide roller; wherein said driving means includes: a driven shaft freely rotatable in said frame, said driven shaft having said cam wheel secured thereto at one end thereof; motive means; clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft; and further including drag brake means mounted on said frame and biasingly urged into frictional engagement with said cam wheel for preventing override of said cam wheel when said clutch means is disengaged.

7. The wire stitching machine of claim 6 wherein said drag brake means includes: a drag brake lever pivotally mounted on said frame; a brake shoe having one end pivotally connected to one end of said lever and its other end arcuately shaped to conform to the periphery of said cam wheel; and biasing means disposed between said lever and said frame for urging said other end of said shoe into frictional engagement with said periphery of said cam wheel.

8. The wire stitching head of claim 6 wherein said clutch means includes a dual-directional clutch.

9. A wire stitching head comprising: a frame; stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length of wire which has been supplied thereto; stitch-driving means movably mounted with respect to said stitch-forming means for driving the stitch formed by said stitch forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of said wire; said wire-feeding means including; a cam wheel mounted on said frame; driving means for selectively rotating said cam wheel; a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means; said guide roller having an outer cover member and a relatively compressible inner core whereby said path of travel can accept wire of preselected various dimensions without changing the diameter of either said cam wheel or said guide roller; wherein said driving means includes: a driven shaft freely rotatable in said frame, said driven shaft having said cam wheel secured thereto at one end thereof; motive means; clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft; further including drag brake means mounted on said frame and biasingly urged into frictional engagement with said cam wheel for preventing override of said cam wheel when said clutch means is disengaged; wherein said clutch means includes a dual-dirEctional clutch; and wherein said dual-directional clutch comprises: an outer member operatively connected to said motive means for rotation in response to energization thereof; an inner member keyed to said driven shaft for rotation therewith; said inner member having at least one cammed outer surface; a roller pin disposed intermediate said cammed outer surface and said outer member, said roller pin movable between a first position wherein said roller pin is freely floating between said cammed outer surface and said outer member and said outer member is free to rotate with respect to said inner member, and a second position wherein said roller pin is wedged between said cammed outer surface and said outer member and said inner member is thereby caused to rotate with said outer member; and movable cage means disposed between said inner member and said outer member for moving said roller pin between its first and second position.

10. The stitching head of claim 9 wherein said movable cage means is normally biased to maintain said roller pin in its second position; and further including trip pawl means mounted on said frame and movable between a first clutch disengage position which maintains said cage means in position to maintain said roller pin in its first position, and a second clutch engage position which permits said cage means to move said roller pin to its second wedging position.

11. A wire stitching head comprising: stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length of wire which has been supplied thereto; stitch-driving means movably mounted with respect to said stitch forming means for driving the stitch formed by said stitch forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of wire; said wire-feeding means including: a cam wheel mounted on said frame; driving means for selectively rotating said cam wheel; a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said continuous supply of wire therebetween; said cam wheel having an arcuate feeding cam of said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means; said guide roller having an outer cover member and a relatively compressible inner core whereby said path of travel can accept wire of preselected various dimensions without changing the diameter of either said cam wheel or said guide roller; wherein said clutch means includes a dual-directional clutch; and wherein said dual-directional clutch comprises: an outer member operatively connected to said motive means for rotation in response to energization thereof; an inner member keyed to said driven shaft for rotation therewith; said inner member having at least one cammed outer surface; a roller pin disposed intermediate said cammed outer surface and said outer member, said roller pin movable between a first position wherein said roller pin is freely floating between said cammed outer surface and said outer member and said outer member is free to rotate with respect to said inner member, and a second position wherein said roller pin is wedged between said cammed outer surface and said outer member and said inner member is thereby caused to rotate with said outer member; and movable cage means disposed between said inner member and said outer member for moving said roller pin between its first and second position.

12. A wire stitching head comprising: a frame; stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length of wire which has been supplied thereto; stitch-driving means movAbly mounted with respect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; and wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of said wire; said wire-feeding means including: a cam wheel mounted on said frame; driving means for selectively rotating said cam wheel; a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said continuous supply of wire therebetween; said cam wheel having an arcuate feeding cam of said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means; wherein said driving means includes; a driven shaft freely rotatable in said frame, said driven shaft having said cam wheel secured thereto at one end thereof; motive means; and clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft; and further including drag brake means mounted on said frame and biasingly urged into frictional engagement with said cam wheel for preventing override of said cam wheel when said clutch means is disengaged.

14. The wire stitching head of claim 12 wherein said drag brake means includes: a drag brake lever pivotally mounted on said frame; a brake shoe having one end pivotally connected to one end of said lever and its other end arcuately shaped to conform to the periphery of said cam wheel; and biasing means disposed between said lever and said frame for urging said other end of said shoe into frictional engagement with said periphery of said cam wheel.

16. A wire stitching head comprising: a frame; stitch-forming means movably mounted on said frame for forming a preselectively shaped stitch from a preselected length of wire which has been supplied thereto; stitch-driving means movably mounted with respect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; wire-feeding means for intermittently supplying said preselected length of wire to said stitch-forming means from a continuous supply of wire; said wire-feeding means including: a cam wheel mounted on said frame; driving means for selectively rotating said cam wheel; a guide roller rotatably mounted on said frame in proximity to said cam wheel to define a path of travel for said continuous supply of wire therebetween; said cam wheel having an arcuate feeding cam of said preselected length secured thereto and projecting into said path of travel as said cam wheel is rotated by said driving means; wherein said driving means includes: a driven shaft freely rotatable in said frame, said driven shaft having said cam wheel secured thereto at one end thereof; motive means; clutch means selectively operative to interconnect said motive means and said driven shaft for rotating said driven shaft; further including drag brake means mounted on said frame and biasingly urged into frictional engagement with said cam wheel for preventing override of said cam wheel when said clutch means is disengaged; wherein said clutch means includes a dual directional clutch; wherein said dual-directional clutch comprises: an outer member operatively connected To said motive means for rotation in response to energization thereof; an inner member keyed to said driven shaft for rotation therewith; said inner member having at least one cammed outer surface; a roller pin disposed intermediate said cammed outer surface and said outer member, said roller pin movable between a first position wherein said roller pin is freely floating between said cammed outer surface and said outer member and said outer member is free to rotate with respect to said inner member, and a second position wherein said roller pin is wedged between said cammed outer surface and said outer member and said inner member is thereby caused to rotate with said outer member; and movable cam means disposed between said inner member and said outer member for moving said roller pin between its first and second position.

18. The wire stitching head of claim 17 wherein said locking means comprises: a bore in said frame transversely oriented with respect to said guide roller supporting shaft; a locking rod slidably positioned in said bore, said locking rod having an arcuate notch of slightly larger radius than said main portion of said guide roller supporting shaft; said arcuate notch receiving said main portion of said guide roller; and means for selectively engaging the inner surface of said notch with the outer surface of said main portion of said guide roller supporting shaft.

19. A wire stitching head comprising; a frame; a lower guide member removably secured to said frame, said lower guide member having a channelway of predetermined width thereon; stitch-forming means removably mounted on said frame in reciprocating relationship with respect to said channelway for forming a preselectively shaped and dimensioned stitch from a preselected length of wire which has been supplied thereto; stitch-driving means reciprocally mounted with respect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; wire feed means for intermittently supplying said preselected length of wire to said stitch-forming means from a supply of said wire; whereby said lower guide member can be removed from said frame and replaced with various other lower guide members having channelways of predetermined differing widths which together with appropriately differing stitch-forming means can produce stitches of various dimensions.

22. A wire stitching head comprising: a frame; a lower guide member removably secured to said frame, said lower guide member having a channelway of predetermined width thereon; stitch-forming means removably mounted on said frame in reciprocating relationship with respect to said channelway for forming a preselectively shaped and dimensioned stitch from a preselected length of wire which has been supplied thereto; stitch-driving means reciprocally mounted with respect to said stitch-forming means for driving the stitch formed by said stitch-forming means into a workpiece positioned in predetermined relationship with respect to said stitching head; wire feed means for intermittently supplying Said preselected length of wire to said stitch-forming means from a supply of said wire; whereby said lower guide member can be removed from said frame and replaced with various other lower guide members having channelways of predetermined differing widths which together with appropriately differing stitch-forming means can produce stitches of various dimensions; wherein said frame includes a front face provided with a recessed slot; and said lower guide member has a rear surface from which is projecting rearwardly extending keying means; said keying means being removably received within said recessed slot.