US2889794A - Unison-feed blindstiching device - Google Patents

Description

V. J. SIGODA UNISON-FEED BLINDSTITCHING DEVICE Jung 9, 1959 5 Sheets-Sheet 1 Filed June 27, 1955 INVENTOR VICTOR J. SIGODA.

BY 9 a E ATTORNEY June 9, 1959 v. J. SIGODA 2,889,794

UNISON-FEED BLINDSTITCHING DEVICE Filed June 27, 1955 5 Sheets-Sheet 2 FIG. 4.

' INVENTOR VICTOR J. SIGODA.

ATTORNEY June 9, 1959 v. J. SIGODA 2,889,794

UNISON-FEED BLINDSTITCHING DEVICE Filed June 2'7, 1955 5 Sheets-Sheet 3 FIG. 5.

0 388 I 80b s2 74! INVENTOR U ATTRNEY VICTOR J. SIGODA.

June 9, 1959 v. J. SIGODA UNISON-FEED BLINDSTITCHING DEVICE 5 Sheets-Sheet 4 Filed June' 27, 1955 mm B m Yw on W n. T'mm INVENTOR VICTOR J. SIGODA.

ATTO

June 9,1959 v. J. SIGODA I 2,889,794

UN ISON-FEED BLINDSTITCHING DEVICE Filed June 27, 1955 5 Sheets-Sheet 5 INVENTOR VICTOR J. SIGODA.

BY e I I w ATTORNEY United States Patent 2,sse,794

UNISON-FEED BLINDSTITCHING DEVICE Victor J. Sigoda, Great Neck, N.Y., assignor to Man-Sew Corporation, New York, N.Y., a corporation of New York Application June 27, 1955, Serial No. 517,973

8 Claims. (Cl. 112 -207) This invention relates to sewing machines of the type having a unison-feed and which are popularly known in the trade as walking foot machines. More specifically it relates to an attachment for such machines for the production of what the trade terms French piping which is a piped binding on the raw fabric edge of a garment or on the surface thereof in which the stitching is concealed within the folds of the piping so that it is not visible on the normally viewed outer surface.

Attachments of this type applied to more conventional forms of lockstitch machines are disclosed in Sigoda application Serial No. 344,040 filed March 23, 1953, now Patent Number 2,801,602, Sigoda application Serial No. 306,631 filed August 27, 1952, now Patent Number 2,769,415, and Sigoda application Serial No. 373,850, filed August 12, 1953, and insofar as said applications and the present application contain common subject matter, this application is a continuation-in-part of each of said applications.

Each of these applications has in common the manner in which the French piping is formed. A folder is utilized which bends the longitudinal edges of a fabric strip back upon themselves into continuous reverse lengthwise folds in substantially U-shaped form with the raw edges rolled within the U. The folded over strip is then bent over the nose of a special presser shoe and presented to the needle for penetration in such fashion that the needle pierces the inner ply of the topmost fold from the inside and then pierces the plies of the lower fold. The subsequent tightening of the interlocked threads as the piping moves rearwardly pulls the plies together to conceal the top fold stitching within the finished piping.

In using the devices of the earlier applications, difficulty is experienced in obtaining uniform results when heavier materials, or extra plies of material, or .wider strips are used because of the increase in the bulk of the work. The increased bulk effects the ability of the feed members to feed the work properly. The feed members consist of the usual four-motion feed dog and spring mounted, downwardly urged, presser foot between which the work is clamped during the needle penetration. When the feed dog moves rearwardly, the teeth or serrations in its top surface engage the underside of the work to move it. The upper surface of the'work is in contact with the undersurface of the presser shoe and as the presser shoe remains in fixed location, the work must slip under the sole of the presser shoe as the work is moved rearwardly by the movement of the feed dog. Proper spring tension on the presser-bar is therefore essential for proper feeding of the work. I

When many plies are being fed, the teeth of the feed dog are less effective through the bulk of the work and increasing the tension exerted on the presser shoe usually improves the feed action. However a point is reached where such increase in pressure results in marring or marking the work with impressions of the feed dog teeth 2,889,794 Patented June 9, 1959 and sometimes, tearing of the undersurface of the work results. The increased pressure also increases the friction exerted on the top surface of the work by the sole of the presser shoe and this causes the top plies to move more slowly than the bottom plies, resulting in twist or distortion of the work.

When heavier work is common, it is frequently the practice to utilize a machine such as the Singer 151W class which is a unison-feed type machine having an additional top feed which makes the machine much more eifective in handling multiplied work.

The feed mechanism of such machines is disclosed in detail in US. Patent No. 989,538 of April 11, 1911, to Albert Rontke. For the present purpose, it will suflice to point out that in such machines, the feed dog does not descend below the surface of the machine bed but instead travels in a horizontal plane on a rather large are whose chord is parallel to and represents the feed path of the machine. This action is produced by mounting the feed dog at the lower, open end of a large frame which resembles the letter U laid on its side, with top and bottom pivotal supports near the closed portion of the U. The U frame is oscillated about its pivots by an eccentric driven from the mainshaft.

The presser foot is a unique, two part affair, being in fact two separate presser feet. The first of these is generally similar to and operates substantially like the conventional presser foot, raising and lowering during portions of the sewing cycle. The second of these feet however, not only raises and lowers during a portion of the sewing cycle, but also moves on the same are forwardly and rearwardly along the feed path taken by the feed dog. This arrangement results from supporting the presser bar for the second presser foot on the upper, open end of the U frame, together with the needle bar so that the second presser foot, the needle and the feed dog have an arcuate movement along the feed path in unison.

The presser feet are linked to operate in such sequence, that as the feed dog, the second presser foot clamped to it and the needle are moving the work rearwardly, the first presser foot is raised above the needle plate to allow the work to move without interference. On the return stroke forwardly, the first presser foot is lowered to clamp the work between it and the needle plate, and both the needle and the second presser foot are raised free of the work.

As the needle is within the work when it is fed rearward-1y, it assists in the feed action, and together with the clamping of the second presser foot to the feed dog during the feed stroke, this makes for a positive feed of both top and bottom plies, and hence twist and distortion are prevented.

When it is desired to apply French piping to work handled by such a machine, the approach disclosed in the earlier applications is ineffective because of the complications arising from the feed movements of the second presser foot and the needle.

In the form of blindstitching utilized, it is necessary to maintain the critical spacing between the nose of the presser shoe over which the folded plies are bent for needle penetration and the needle in order to obtain proper nipping or penetration of the top fold. Since the relative position of the folder outlet is also of importance in these arrangements, the movement of the presser foot nose and needle to and from the folder outlet would normally affect the operation of such an attachment.

Accordingly it has been a main object to provide an attachment for producing French piping on a sewing machine of the unison-feed type and this has been accomplished by carrying at least the outlet portion of the folder on the same frame that moves the needle, second presser foot and feed dog, so that the folder outlet also moves in unison with the feed members of this type of machine.

It has been found that moving the folder on an are similar to that on which the feed dog normally moves in such machines introduces distortion. It has been a further object to overcome these defects by rearranging the movements of the feed dog and the folder outlet so that they actually travel on the chord rather than on the arc of the feed path. It has been found possible to have such diversity of top and bottom feed movements in the machine by modifying the effective section of the nose of the presser shoe so that it olfers minimal frictional contact with the top plies of the work during the feed stroke. Since the needle remains in the work during the feed stroke, misalignment of plies cannot occur and since the work has already been sewn before it is fed rearwardly, the different top and bottom feed motions have no serious efiect on the proper operation of the attachment.

Since the blind'stitch operations of this type the spacing between the needle and the nose of the second presser foot is critical, it has been a still further object to provide adequate means for varying the relative position of the nose with respect to the needle in the adjustable mounting for the foot on the second presser bar.

Other objects and features will become evident from the following detailed description and drawings, in which:

Fig. l is a front elevation of a unison-feed machine showing the attachment with one folder arrangement applied thereto;

Fig. 2 is an end elevation corresponding to Fig. 1 taken from the needle head end of the machine with the cover plate removed;

Fig. 3 is a plan view of the attachment of Figs. 1 and 2 applied to the machine, the arm standard, the overhanging arm and the needle head being omitted;

Fig. 4 is a similar plan view showing a different folder arrangement to accommodate Wider material strips;

Fig. 5 is a plan view similar to Figs. 3 and 4, showing a third folder arrangement to accommodate still wider material strips;

Fig. 6 is a plan view of a portion of the sewing machine bed showing the basic parts of the modified feed dog actuating mechanism, and partly broken away, the hinged slide plate on which at least the outlet portion of the folder is carried;

Fig. 7 is a plan view somewhat similar to Fig. 6 showing the hinged slide-plate and a guide-plate on which the separated portions of the folders of Figs. 4 and 5 are suppor d;

Fig. 8 is a sectional view taken on line 88 of Fig. 3 showing only the folder outlet mounted on the hinged slide-plate and showing how the guide-plate is secured to the base of the sewing machine;

Fig. 9 is a detail, perspective view ,of the end of the folder outlet;

Fig. 10 is a similar view showing the folded fabric strip being bent over the blindstitch nose of the second pres e foot;

Fig. 11 is a similar view but showing the needle just as it begins to nip or penetrate the inner ply of the topo fo d o the ork;

Fig. 12 is a similar View showing the needle fully penetrating the top and bottom folds of the work;

Fig. 13 is an exploded view in perspective of the second presser foot; and

Fig. 14 is an exploded view in perspective showing the first presser foot and the second presser foot, assembled, in relative position.

In describing the invention only limited reference will be made to the partsof the unison-feed sewing machine which -.is well knovm in .the art. Further particulars may be obtained with respect thereto by referring to the Rontke Patent No. 989,538.

Il the drawings, and more particularly with respect to Figs. 1 and 2, the sewing machine comprises a bed-plate 4 1, the standard 2, the overhanging arm 3 and the needle head 4. Iournalled within bearings in arm 3 is the main or needle-bar actuating shaft 5 having at one end the handwheel 6, and at the end within the head 4, a crank-block 7 for vertically reciprocating the needle-bar 8 which carries needle 9. The needle-bar and the crankblock are connected by stud collar 10 on the needle-bar and link 11 connected between the stud collar and the crank-block. The needle-bar is journalled for vertical reciprocation in bearings in lugs 12 and 14 formed integrally with an arm 15 of the oscillatory feed frame 16.

Frame 16 is mounted upon oppositely arranged pintle bearings comprising the stud 18 threaded into the arm 3 and pin 19 secured by screw 20 in the arm 21 of the oscillating frame, the tapered portion 22 of the pin entering an opening of like shape in the bed-plate 1. The oscillatory frame connects for operation with the mainshaft 5 by means of a pin 24, eccentric strap 25, and eccentrio 26, the latter being secured to the side of the belt pulley 28. Cleat belt 29 connects upper pulley 28 and lower pulley 30 to drive the looper actuating shaft 31 carrying the loop-taker 32. 33 denotes the needle thread take-up operated from the main-shaft in conventional fashion, 34- is the spring depressed first presser-bar provided at its lower end with presser foot 35, and 36 is the needlethread tension device.

The second presser-bar 38 is also mounted for vertical movement in lugs 12 and 14, and at its lower end carries a support 39 on which is pivotally mounted a modified step-feeding foot 40. This foot and its support will subsequently be further described.

At the upper end of bar 38, link 41 is pivotally attached thereto. The opposite end of link 41 is pivotally connected with arm 42 of bell crank lever 43 fulcrumed at 44 to the presser-bar lifting lug 45 carried by the presserbar 34. The upper arm of lever 43 is connected with one end of link 46 and the other end of the link is pivotally connected with crank-arm 48. The crank-arm is rigidly connected to the crank-block 7 at a predetermined distance off center to obtain the desired movement of bar 38.

In the feeding operation, rotation of crank-block 7 rocks bellcrank lever 43 through link 46. The bellcrank lever, through link 41, effects vertical movement of presser-bar 38 when the first presser-bar 34 is clamped on the work. However, when foot 40 is in engagement with the work, through connections 46, 42 and 41, crank-blocks 7 acts to raise presser-bar 34 to disengage presser-foot 35 from the work. The vertical movements of the respective presser-bars alternate to raise bar 34 to release the work during the feeding operation at which time bar 38 is lowered to effect engagement of the work with the feed dog, and to lower bar 34 to hold the work against accidental movement when needle 9 and foot 40 are raised out of engagement with the work at such time as the needle, foot and feed dog are being returned to their forward positions for effecting the next subsequent rearward feed stroke by the oscillation of frame 16.

As indicated in Fig. 14, presser-foot 35 may be provided with bottom serrations which correspond to similar serrations on plate 52 to assist in clamping the work during the return portion of the feed stroke.

Referring now to Fig. 6, the free end of frame 16 carries an extension member 49. Frame 16 has a we tangular recess (not shown) in which the correspondingly shaped end of member 49 seats. These parts are sccured together by a screw (not numbered) whose head is shown (Fig. 6) in the counterbored recess in member 49 near numeral 21. This construction is generally similar to and is shown in Fig. 3 of said Rontke Patent No. 989,538, in which 86 corresponds with frame 16 herein and 89 corresponds with extension member 49 herein. Member 49 has a raised, integrally formed, circular boss 50 which is perforated with needle hole 51. The top surface of boss 50 moves in a horizontal plane, as a result of the oscillatory excursions of frame 16, which corresponds substantially with the surface of plate 52 which replaces the needle plate of the machine.

The oscillation of extension member 49 about its pivot at 19 is communicated to and imparts movement to slide-plate 53, Fig. 7 by means of boss 50 which fits into elongated opening 54 with freedom but without too much play. The arcuate motion thereby imparted is converted to a straight line movement along the chord by means of a pair of spaced guides. One guide consists of two oppositely extending bars 55 integrally formed with the rectangular portion 56 of the slide-plate which are received in a long, rectangular slot 58 undercut in plate 52. The second guide consists of a rabbet 59 undercut in guide-plate 60 (Fig. 8) in which the edge of the slide-plate is guided. While sufficient clearance is provided to permit free movement of slide-plate 53 in a straight-line, excess play is avoided. Slot 58 and rabbet 59 are arranged in parallel relationship.

The rectangular portion 56 about opening 54 acts as the feed dog and may, if desired, be serrated or provided with teeth.

The extremes of movement of feed dog portion 56 of slide-plate 53 within the rectangular notch provided therefor in plate 52 is indicated in broken line in Figs. 6 and 7.

Slide-plate 53, Fig. 7, is provided with spaced hinge bosses 61 by means of which a folder supporting bracket 62 having a complementary hinge boss 63 may be pivotally mounted by a hinge pin. The vertical angular position of bracket 62 about the hinge pin, and accordingly the inclination of the folder or folder portion mounted thereon, may be adjusted by means of a setting screw 64 (Fig. 8) and the adjusted position may be locked against downward movement by lock-nut 65. Upward movement of bracket 62 is provided to permit the folder to be raised when the presser feet are lifted by manipulation of lift lever 66. Such upward movement may take place against the tension of spring 67 coiled about the shank of a headed stud 68 which passes through an opening in slide-plate 53 and whose upper end 69 is anchored in bracket 62. As indicated in Figs. 11 and 12, presser foot 35 extends somewhat under the bottom surface of nose 7217. Hence when foot 35 is raised by manipulation of hand lever 66, the portion of foot 35 under folder 72 comes into contact with it and causes folder 72 to rise also.

Referring again to Fig. 8, it will be seen that guideplate 68 may be attached to the machine bed-plate 1 by several bolts 70 passing through clamp brackets 71 and threaded into the guide-plate. One arm of such brackets engages the undersurface of bed-plate 1 and tightening bolts 78 clamps the guide-plate to the bed-plate.

Referring now to Fig. 3, folder 72 is secured to bracket 62 by screws 73. Folder 72 is a one piece affair used when relatively narrow strips are being folded to form piping, the inlet 72a corresponding to the width of the strip. The tension ladder 72 is provided for the usual purpose of introducing some drag on the fabric strip to minimize the possibility of curling, twisting or'fouling as the strip is introduced into the folder. The folder is of conventional structure and is channelled longitudinally to bend the long edges of the fabric strip into reverse folds such as is illustrated in Figs. to 12. The outlet 72b of the folder is provided'with a Dutch Nose 75 (Fig. 9) and stops 76, Figs. 9 and 11, to form the folded strip for the subsequent bending around the nose of the second presser foot for the blindstitch operation. Inlet 72a is soldered to the plate which carries nose portion 72b. This plate is shown in Fig. 3 as the rectangular member through which screws 73 pass to secure this one piece folder to bracket 62. i

Fig. 4 shows a similar folder 78 which is designed to handle wider strips. It is separated into two sections,

the inlet section 78a which is supported by bracket 79 on guide-plate 60 and the outlet section 78b which is attached to the rectangular plate through which screws 73 pass to secure it to bracket 62. The inlet section carries a modified form of tension ladder 74a. Inlet section 78a is angularly disposed with respect to the outlet section 7812 because there is not suflicient room under arm 3 to mount folder 78 in the same manner as folder 72. As wider fabric strips are used, it is necessary to employ a proportionately longer channel portion in the folder in order to effect proper folding. It will be noted that the channel portions of the folders of Figs. 3, 4 and 5 become progressively longer, and because the space under arm 3 is limited, accommodation for this increase in length is obtained by separating the sections of the folder and mounting one at an angle to the other.

In Fig. 5 a third form 80 of the folder is shown. This is for still wider strips, and the inlet portion 80a is disposed at an angle of about 75 degrees with respect to the centerline of outlet portion 80b in order to avoid interference with standard 2. Because of this sharp turn, roller 81, supported on guide-plate 60, is interposed between the sections to properly guide the folded strip from one to the other.

Inlet section 80a is supported on guide-plate 60 by bracket 82 and tension ladder 74b is attached to section 88a. Outlet section 80b is attached to the rectangular plate through which screws 73 pass to secure it to bracket 62.

A platform 83 is attached to any of the nose portions 72b, 78b, or 8% in position so that it can act as a support over which an additional piece of material such as the edge of a garment or a collar to which the folded strip is to be applied as a French piping, may be fed to be inserted within the folds as they emerge from the nose of the folder. Platform 83 is generally similar in construction, function and use to guide 72 shown in Figs. 3 and 4 of Seaman Patent No. 1,969,950. I

The second presser foot 40 has a nose portion 84 around which the folded plies emerging from the folder outlet are bent as shown in Fig. 10 for the subsequent needle penetration as shown in Figs. 11 and 12. The position of nose 84 with respect to needle 9 is critical and to permit proper adjustment of this spacing, foot 40 is attached to its support 39 in the following manner.

Foot 48 is pivotally mounted by means of shoulder screw 85 which passes through the top opening 86 in foot 40 and is threaded into corresponding opening 88 in support 39. The shoulder 89 on screw 85 prevents locking of foot 4-8 against support 39 but the tension washer 90 interposed between the head 91 of screw 85 and the side 92 of foot 40 supplies enough friction to maintain positional adjustments.

Stud 93 provided with an eccentric shoulder 94, fits within elongated opening 95 in foot 40 and is held in support 39 by a concentric shank portion 96 which fits into clamp opening 98 at the bottom of support 39. The clamp is closed to retain the eccentric stud in fixed position by tightening screw 99.

It can be readily seen that in the completely assembled foot, as shown in Fig. 14, when the eccentric stud 93 is rotated as by means of a screwdriver inserted in slot 100, nose 84 will move in an arcuate path about its pivot 85, and that when the assembled foot is mounted on the presser-bar 38, that this will result in moving the nose 84 to and from the needle 9. Lock screw 101 passes through the unnumbered clearance hole in member 40, and is then threaded into opening 102 to secure foot 40 in adjusted position against its support 39. The assembled foot is attached to presser bar 38 by clamp portion 103 which is closed by tightening screw 104.

Mounting the folder for movement with oscillating frame 16 affects the feed action of the machine so that the fabric strip is drawn through the folder at a different part of the stitching cycle. Normally, if the folder were mounted in fixed position on the bed of the machine, feed action or drawing of the strip through the folder would take place when the step-feeding foot and the feed dog were clamped together with the work between them and while they were moving to the rear. This would occur because there would then be relative movement between the folder and the feed elements. When the folder is mounted to move with the feed elements, there is no relative movement between them and no pulling would be exerted on the work in the folder. However, when the work is clamped to plate 52 by the first presser foot 35, and when the folder 72, and the disengaged stepfeeding foot 40 and feed dog 56 are moving forwardly, the relative movement between the first presser foot and the folder causes the work to be pulled through the folder.

The method of producing blindstitching with this attachment is the same as that disclosed in the earlier applications previously mentioned. As will be noted from Fig. 10, the outlet end 72!) is mounted above nose 34 so that the folded strip in leaving outlet 72b to pass about nose S4 assumes a substantially vertical position in a plane parallel to the needle path, as is best illustrated in Figs. 11 and 12. By properly positioning outlet 72b initially with respect to needle 9, the folded plies will be in the path of travel of the needle, and by adjusting the position of nose 84 as previously described, the folded plies will be in position so that the needle will only pass through the innermost ply of the top fold. The stitching will therefore not show on the outer surface of this top fold. After passing through this inner ply, the needle will continue to pass downwardly through the remaining plies to form the usual stitch locking the folded over strip into a tube or piping. The stitched piping then passes under nose 84 and the sole of presser foot 35. The feed action previously described continues to draw the strip through the folder and under both presser-feet to emerge at the rear of the machine as finished French piping.

While the presently preferred embodiments have been described in detail for the purpose of illustration, it is to be understood that the invention is not to be limited to the details of construction shown and described, but is to be construed broadly within the spirit and scope of the appended claims.

What is claimed is:

1. In a sewing machine of the unison-feed type having an oscillatory feed actuating frame and a support member carried thereby; stitchforming means including a reciprocatory needle bar and a needle carried thereby; and feed means including a first presser-bar and a presser foot carried thereby; a second presser-bar and a stepfeeding foot carried thereby and a feed dog on said support member; in which the needle-bar and the second presser'bar are journalled in said frame for independent .vertical movements and in which the needle-bar, the stepfeeding foot and the support member move in unison along the line of feed as said frame is oscillated: means for producing blindstitching in conjunction with said stitchforming and feed means, comprising a slide plate mounted on the machine for reciprocation parallel to the line of stitching; a connection between said slide plate and said support member for reciprocating the slide plate in the same sense as the support member is oscillated; a strip fabric folder having an inlet portion and an outlet portion; ,the outlet portion of said folder being carried by said slide plate for unison travel with said step feeding foot; said step feeding foot being provided with a blindstitch nose disposed transversely of the line of stitching; the outlet of said folder outlet portion being positioned closely adjacent the path of needle travel for guiding the folded fabric plies emerging therefrom. downwaridly around said nose into position for selected needle penetration.

2. In asewing machine of the unison-feed type having an oscillatory feed actuating frame and a support member carried thereby; stitohforming means including a reciprocatory needle bar and a needle carried thereby; and feed means including a first presser-bar and a presser foot carried thereby; a second presser-bar and a stepfeeding foot carried thereby and a feed dog on said support member; in which the needle-bar and the second presser-bar are journalled in said frame for independent vertical movements and in which the needle-bar, the stepfeeding foot and the support member move in unison along the line of feed as said frame is oscillated: means for producing blindstitching in conjunction with said stitchforming and feed means, comprising a slide-plate, guide plates for directing said slide-plate for straight line movement along the feed path, said guide plates being mounted on the machine bed on opposite sides of said slide-plate, each of said guide-plates having complementary parallel means connecting with said slide-plate to restrict its movement to a straight line, a boss on said support member and an elongated opening in said slideplate to receive said boss to communicate movement from said support member to said slide-plate to move it as said support member is moved onits arcuate path, strip fabric folding means having an outlet supported on said slide-plate, and a modified step-feeding foot provided with a nose around which the folded fabric plies emerging from said folder may be bent for selected needle penetration of said plies, said outlet being mounted so that it is above and closely adjacent said nose in such position that the folded plies emerging from the outlet are in a substantially vertical plane which lies in the path of needle travel.

3. In a sewing machine of the unison-feed type having an oscillatory feed actuating frame and a support member carried thereby; stitchforming means including a reciprocatory needle bar and a needle carried thereby; and feed means including a first presser-bar and a presser foot carried thereby; a second presser-bar and a step-feeding foot carried thereby and a feed dog on said support member; in which the needle-bar and the second presser-bar are journalled in said frame for independent vertical movements and in which the needle-bar, the step-feeding foot and the support member move in unison along the line of feed as said frame is oscillated: means for producing blindstitching in conjunction with said stitchforming and feed means, comprising a strip fabric folder having an outlet portion which is mounted on the machine bed for movement with said support member and a modified step feeding foot comprising a support portion affixed to the presser-bar and a foot portion pivotally mounted on said support portion, said foot portion having an elongated opening therein, means to adjust said foot portion about its pivot comprising a stud adjustably mounted in said support portion and having an eccentric shoulder fitted within the elongated opening of the foot portion and means to lock the adjusted position of said foot portion on said support portion, said foot portion also being provided with a nose around which the folded fabric plies emerging from said outlet may be bent for selected needle penetration of said plies, said outlet being mounted so that it is above and closely adjacent said nose in such position that the folded plies emerging from the outlet are in a substantially vertical plane which lies in the path of needle travel.

4. In a sewing machine of the unison-feed type having an oscillatory feed actuating frame and a support member carried thereby; stitchforming means including a reciprocatory needle bar and a needle carried thereby; and feed means including a first presser-bar and a presser foot carried thereby; a second presser-bar and a step-feeding foot carried thereby and a feed dog on said support member; in which the needle-bar and the second presserbar or journalled in said frame for independent vertical movements and in which the needle-bar, the step-feeding footand the support member move in unison along the line of feed as said frame is oscillated: means for producing blindstitching in conjunction with said stitchforming and feed means, comprising a slide-plate, guide plates mounted on the bed of the machine on opposite sides of said slide-plate, strip fabric folding means supported on said slide-plate and one of said guide plates, comprising a folder outlet portion mounted on said slide-plate and a folder inlet portion mounted on said guide plate, and a modified step-feeding foot provided with a nose around which the folded fabric plies emerging from said outlet may be bent for selected needle penetration of said plies, said outlet portion being mounted so that it is above and closely adjacent said nose in such position that the folded plies emerging from the outlet are in a substantially vertical plane which lies in the path of needle travel.

5. In a sewing machine of the unison-feed type having an oscillatory feed actuating frame and a support member carried thereby; stitchforrning means including a reciprocatory needle bar and a needle carried thereby; and feed means including a first presser-bar and a presser foot carried thereby; a second presser-bar and a step-feeding foot carried thereby and a feed dog on said support member; in which the needle-bar and the second presserbar are journalled in said frame for independent vertical movements and in which the needle-bar, the step-feeding foot and the support member move in unison along the line of feed as said frame is oscillated: means for producing blindstitching in conjunction with said stitchforming and feed means, comprising a slide-plate, guide plates mounted on the bed of the machine on opposite sides of said slide-plate, strip fabric folding means supported on said slide-plate and one of said guide plates, comprising a folder outlet portion mounted on said slide-plate and a folder inlet portion mounted on said guide plate at an angle to the centerline of the folder outlet portion, and a roller interposed between said portions around which the folded strip may be guided from the inlet portion to the outlet portion, and a modified step-feeding foot provided with a nose around which the folded fabric plies emerging from the outlet of said folder may be bent for selected needle penetration of said plies, said outlet being mounted so that it is above and closely adjacent said nose in such position that the folded plies emerging from the outlet are in a substantially vertical plane which lies in the path of needle travel.

6. A blindstitch attachment for a unison-feed sewing machine having an oscillatory feed actuating frame and a step-feeding presser-bar; comprising a slide-plate adapted to be mounted on the machine bed for movement with the feed frame, guide means including a fixed plated mounted on the machine and cooperating with said slideplate to restrict its movements to a straight line along the feed path, a folder outlet portion mounted on said slide-plate, a folder inlet portion mounted on said guide plate at an angle to the centerline of the folder outlet portion, and a modified presser-foot adapted to be carried by said presser-bar, said foot having a nose around the edge of which the folded plies emerging from said folder may be bent for selected needle penetration.

7. In a sewing machine of the unison-feed type having an oscillatory feed actuating frame and a support member carried thereby; stitchforming means including a reciprocatory needle bar and a needle carried thereby; and feed means including a first presser-bar and a presser foot carried thereby; a second presser-bar and a step-feeding foot carried thereby and a feed dog on said support member; in which the needle-bar and the second presser-bar are journalled in said frame for independent vertical movements and in which the needle-bar, the step-feeding foot and the support member move in unison along the the line of feed as said frame is oscillated: means for producing blindstitching in conjunction with said stitchforming and feed means, comprising a slide-plate, guide members on either side of said slide-plate to restrict the movement of said slide-plate to a straight line along the feed path, a bracket pivotally mounted on said slide-plate, means to adjust the vertical inclination of said bracket about its pivotal support, comprising a manipulatable member threaded into part of said bracket and resting upon the slide-plate to limit downward movement of said bracket, strip fabric folding means having an outlet supported by said bracket, and a modified step-feeding foot provided with a nose around which the folded fabric plies emerging from said outlet may be bent for selected needle penetration of said plies, said outlet being mounted so that it is above and closely adjacent said nose in such position that the folded plies emerging from the outlet are in a substantially vertical plane which lies in the path of needle travel.

8. In a sewing machine of the unison-feed type having an oscillatory feed actuating frame and a support member carried thereby; stitchforrning means including a reciprocatory needle bar and a needle carried thereby; and feed means including a first presser-bar and a presser foot carried thereby; a second presser-bar and a step-feeding foot carried thereby and a feed dog on said support member; in which the needle-bar and the second presser-bar are journalled in said frame for independent vertical movements and in which the needle-bar, the step-feeding foot and the support member move in unison along the line of feed as said frame is oscillated: means for producing blindstitching in conjunction with said stitchforming and feed means, comprising a slide-plate, guide members on either side of said slide-plate to restrict the movement of said slide-plate to a straight line along the feed path, a bracket pivotally mounted on said slide-plate, means to adjust the vertical inclination of said bracket about its pivotal support, and yieldable means opposing but permitting limited upward movement of said bracket about its pivotal mounting, strip fabric folding means having an outlet supported by said bracket, and a modified stepfeeding foot provided with a nose around which the folded fabric plies emerging from said outlet may be bent for selected needle penetration of said plies, said outlet being mounted so that it is above and closely adjacent said nose in such position that the folded plies emerging from the outlet are in a substantially vertical plane which lies in the path of needle travel.

References Cited in the file of this patent UNITED STATES PATENTS 621,146 Rontke Mar. 15, 1899 814,603 Herman Mar. 6, 1906 1,346,884 Gray July 20, 1920 1,360,357 Bauer Nov. 30, 1920 1,969,950 Seaman Aug. 14, 1934 2,025,531 Seaman Dec. 2A, 1935 2,339,648 Nissen et a1. Ian. 18, 1944 2,724,353 Fishman et a1 Nov. 22, 1955

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