US2857866A

US2857866A - Stitch-foot for use in double-needle sewing machines for the manufacture of helical-wire slide fasteners

Info

Publication number: US2857866A
Application number: US641165A
Authority: US
Inventors: Porepp Hans
Original assignee: OPTI WERK GmbH
Current assignee: OPTI WERK GmbH; OPTI-WERK GmbH
Priority date: 1956-03-01
Filing date: 1957-02-19
Publication date: 1958-10-28
Anticipated expiration: 1975-10-28
Also published as: CH350945A; DE1030154B; FR1172753A; GB855075A; BE555447A

Description

Oct. 28, 1958 H. POREPP 7,

STITCH-FOOT FOR USE IN DOUBLE-NEEDLE SEWING MACHINES FOR THE MANUFACTURE OF HELICAL-WIRE SLIDE FASTENERS Filed Feb. 19, 1957 2 Sheets-Sheet 1 F/G'. a

Oct. 28, 1958 H. POREPP 2,857,866

STITCH-FOOT FOR USE IN DOUBLE-NEEDLE SEWING MACHINES FOR THE MANUFACTURE OF HELICAL-WIRE SLIDE FASTENERS Filed Feb. 19, 1957 2 Sheets-Sheet 2 ,g m l vylllllll-lrlllrlllf/l #vravrae; M/VS FOX/"ff United States Patent 2,857,866 Patented Oct. 28, 1.958

ice

STITCH-FOOT FOR USE IN DOUBLE-NEEDLE SEWING MACHINES FOR THE MANUFAC- TURE F HELICAL-WERE SLIDE FASTENERS Hans Porepp, Essen, Germany, assignor to tlpti Wei-h G. m. b. H., Essen, Germany This invention relates to the manufacture of helicalwire slide fasteners consisting of two helical wires of metal or plastic material and of opposite twist which through suitable profiling or the like engage or disengage each other.

For the attachment of these helical wires to two attachment tapes of textile or artificial material the invention proceeds as follows: The helical wires are provided on the sides thereof located opposite the sides on which they engage each other with a longitudinally extending thread resting against the turns and are secured to the wires by a fastening thread between every turn of the Wires. These longitudinally extending threads and fastening threads are then, together with a guide cord covering up the threads sewed to the attachment tapes. For this purpose the two helical wires provided with the fastening threads are brought into engagement with each other, whereupon the longitudinally extending threads and their fastening threads as well as the guide cords are sewn to the two attachment tapes by means of double-needle sewing machines. It is understood that the customary sewing machines of this type can be used for this purpose only with greatest difiiculty and unsatisfactory results, as it is necessary to arrange the two attachment tapes, the two interlocked helical wires provided with the longitudinally extending threads and the fastening threads therefor, as well as the two guide cordsthat is to say, five semi-finished products of rather different propertiesaccurately on top of each other (on each side of the space 1, Figure 1), directly under the needles, in order to achieve a perfect sewing result.

In order to make sure that the different parts of the helical-wire slide fasteners can be relied upon to register correctly and then can be sewed up together accordingly, without making it necessary for the woman doing the needlework or for an assistant of the latter to pass the individual parts onto the machine, or to an attachment for the purpose, the invention proposes to employ for the manufacture of helical-wire slide fasteners of the aforesaid kind a novel type attachment, herein called a stitch-foot, for a double-needle sewing machine. The invention is principally characterized by the feature: that the stitch-foot consists of a lower plate and an upper plate and is provided on the feed-in side between the two plates with a guide member along which the two attachment tapes slide in flatly crossed position with the two inner edges confronting each other, whereupon the two attachment tapes are adjusted to straight-lined and parallel position in a guide chamber located between the two plates and corresponding in thickness and width to the dimensions of the completed slide fastener; that the lower plate is provided behind the place where the two attachment tapes cross each other with two bores for the passage of the needles; that the upper plate is provided with a slot extending from the forward edge of the plate to the passage for the needles and corresponding in 7 width to the width of the two interlocked and longitudinally moving helicalwires; that in the area ofthe More said slot before the needles two longitudinally extending guides are located for the guiding of the two guide cords covering up the longitudinally extending threads and fastening threads of the helical wires; and thatfro-m the passage for the needles a groove extends along the: underside of the upper plate to the rear end of the latter whose width and height corresponds to. the width and. height of the two helical wires provided with the. sewed on guide cords.

' By means of this novel. type of stitch-foot it is possible to sew these different semi-finished products, whose dimensions vary within slight permissible limits, in accurately guided condition, speedily together to form.helicalwire slide fasteners. It is important that the two attachment tapes be fed to the stitch-foot in flatly crossed position, as it is possible only in this Way to maintain the two inner edges of the tapes, independent of slight variations in width, constantly in uniformly tensioned condition and at a uniform distance from each other, sothat they assume in the stitch-foot particularly before the needles-correct positions with respect to each other. The use of guiding means for the edges of the tapes for the straight-lined and parallel feeding of the two tapes into the stitch-foot doe not produce satisfactory results, as has been found out through numerous tests. The reason for this is that there are always slight variations in width, of these textile bands, which variations may result in variations of the. position of the bands with respect to each other in the area of the two needles, and in the manufacture of arched or crooked slide fasteners.

Additional features and advantage of the invention will be understood from the following detailed description taken in connection with the accompanying drawings forming a part of this specification and in which an embodiment of the principle of the sewing action for the manufacture of helical-wire slide fasteners, and also an embodiment of the stitch-foot of the invention have been shown by way of example. However, Iwish to say that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified, so long as such changes or modifications mark no material departure from the salient features ofthe invention as expressedin the appending claims;

In the drawings, in whichlike parts are referred to by the same reference numerals,

Fig. 1 is a top planview of the attachment tapes; of the interlocked helical wires provided'with longitudinally extending threads and fastening threads; andof the guide cords guided in the stitch-foot;

Fig. 2 is a side elevation of Fig. 1;

Fig. 3 is a cross-section on line Ill-IIl"of"Figs. 1 and'2;

Fig. 4 is a side elevation of the stitch-foot of themvention';

Fig. 5 is (left hand side) a front viewof'the feed'side of the stitch-foot; and (right hand side) a cross-section directly before the two needles;

Fig. 6 is a top plan view of'the stitch-foot. At the lower half of the figure the upper plate of the stitch-foot has been removed.

Fig. 7 is a top plan view of the lower plate of the stitch-foot;

Fig. 8 is a side view of the lower plate of Fig; 7;

Fig. 9a is a top plan view of the cross-guide for thetwo attachment tapes;

Fig. 9b'is a front view of the cross-guide for the two: attachment tapes;

Fig. 10 is a top plan view of the upper plate offthe stitch-foot;

Fig. 10a is a central longitudinal section through the: upper plate of Fig. 10;

Fig. 10a isa frontview of the upper plate;

Fig. 11a is atop plan view of acordguide;

Fig. 11b is a side view of a cord guide.

The helical-wire slide fasteners consist of two helical Wires of opposite twist A A which through suitable profiling or by some other means tightly interlock; of two attachment tapes B B and of two guide cords C and C The guide cords serve the purpose of guiding the two helical wires, of metal or plastic material, in a slider for producing the interlocking engagement or for severing it. For securing these parts to each other by stitching, the two helical wires A A are provided along their outsides with longitudinally extending threads A A which are secured to the helical wires by means of fastening threads. Then the helical wires are placed upon the tapes B B along the inner edges of the latter; thereupon the longitudinally extending threads A A are covered up by the guide cords C C and then the cords and the longitudinal threads and fastening threads of the latter are sewed to the two tapes. For this a doubleneedle sewing machine is employed; and for obtaining a correct covering up the invention uses a stitch-foot hereinafter described to which the two attachment tapes B and B are fed as shown in Fig. 1, that is to say, flatly crossing each other. Provided in the stitch-foot is a guide member, for example an elongated rib F, whose width corresponds to the distance 1 between the two inner edges of the two tapes of the completed slide fastener. The height of the rib F corresponds to the thickness of the two tapes B B Directly in front of the two sewing needles D D the interlocked helical wires A A are fed to the two tapes B B longitudinally towards the needles, over the tapes. Furthermore, there are fed, likewise longitudinally towards the needles, over the tapes, the two guide cords C C in such fashion that they cover up the longitudinal threads A A and fastening threads a. Thereafter these parts are sewed together.

In order to be able to carry out the aforedescribed method of sewing the parts A B C and A B C together with accurate precision and great speed, the invention employs the stitch-foot as hereinafter described. This stitch-foot consists essentially of a lower plate 1 and an upper plate 2, which are provided with a stitchfoot handle 3. The lower plate is of rectangular shape and laterally terminates in two longitudinally extending upwardly projecting

ribs

5 and 6. These two

ribs

5 and 6 have, compared with the rear surface portion 1a of the plate, a height corresponding to the thickness of the tapes B B and their distance from each other corresponds to the entire width of the completed slide fastener. The forward portion 1b of the plate surface is, compared with the height of the

ribs

5 and 6, of larger depth than the rear surface portion 1a, whereby this depth corresponds to at least double the thickness of the tapes B B Behind the step between the surface portions 1b and 112 there are two bores 7 through which the sewing needles D D operate. Ahead of the bores 7, in the area of the forward surface portion 1b, there is arranged the guide member for the crosswise feeding of the two attachment tapes B B According to Figs. 9a and 91), this guide member consists of a thin plates whose entire thickness corresponds to the depth of the forward surface portion 1b of the lower plate 1 as compared with the

ribs

5 and 6 of this plate. The width of this plate 8 is smaller than the distance of the

ribs

5 and 6 from each other, so that this plate after its arrangement in the recess 1b of the lower plate 1 can be shifted in a transverse direction. For this purpose the plate is provided with laterally projecting portions 8a and 81) extending through recesses 9 of the lower plate 1, so that in this way a guide is provided for the plate 8 as shown in Fig. 7 in broken lines. For the adjustment of the plate 8 the projecting portion 8a of the plate is provided at its free end with a downwardly bent flanged end portion 80,

. and this downwardly bent end portion 80 is provided with a threaded bore for the engagement therein of a setscrew 8d. In addition to this, the projecting portions guide cords C C 8a and 8b are provided with transversely extending

elongated slots

10 and 11 by means of which the guide plate 8 can be screwed to the lower plate 1 of the stitch-foot in the required adjusted position.

The plate 8 is provided in its under surface and upper surface with

seats

12 and 13, of which one is positioned on one side and the other one on the other side of the longitudinal center line of the plate. The inner delimitation shoulders 14 and 15 of these seats, whose depth corresponds to the thickness of the attachment tapes B B extend from the forward end to the rear end of the plate in oppositely inclined directions toward the longitudinal center line of the plate and intersect the longitudinal center line shortly ahead of the rear edge of the guide plate 8 in such manner that the rear ends of the two shoulders TM and 15 are positioned in a transverse direction at a. slight distance from each other, which distance corresponds to the distance from each other of the two inner edges of the two attachment tapes B B of the completed slide fastener. It is understood that the guide plate 8 is so adjusted in the lower plate 1 of the stitchfoot that the longitudinal center lines of this guide plate and of the lower plate register vertically. Placed upon this lower plate 1 is then the upper plate 2 (of width equal to that of the lower plate 1) which is secured to the plate 1 by means of bolts extending through the bores 16 of plate 1 and correspondingly threaded bores 17 of plate 2. Because of the flat undersurface of the upper plate 2 there is defined between the

plates

1 and 2 in the surface area 1a of the lower plate 1 a rearwardly extending guide chamber having the width of the completed slide fastener and a height corresponding to the thickness of the attachment tapes B B The distance between the forward edge and rear edge of the guide plate 8 is smaller than the distance between the forward edge of the lower plate 1 and the step-edge 10, so that between the rear edge 82 and the step-edge 1c a deep recess exists corresponding to the entire thickness of the plate 8. This makes it possible for the tapes B B which cross each other in flat position, and which pass through the

recesses

12 and 13 of the guide plate 8, to adjust themselves horizontally before entering the space between the surface portion 1a and the undersurface of the upper plate 2.

The upper plate 2 (Figs. 10, 10a) is provided with a slot 19 extending from its forward edge as far as the passage 18 for the two needles, which passage 18 registers with the two bores 7 of the lower plate, and this slot 19 is of a width corresponding to the width of the interlocking helical wires A A and of the guide cords C C Behind the passage 18 for the needles the upper plate is provided on its underside with a longitudinally extending groove 20 whose width and depth correspond to the width and depth of the joined helical wires A A and the sewed on guide cords C C To the slot 19 the two interlocked helical wires A A are fed in the longitudinal direction of the slot 19, and from above the two guide cords C C are fed in such manner that these guide cords correctly register with, that is to say, are correctly positioned on top of the longitudinally extending threads A A and fastening threads of the helical wires. For this purpose the upper plate 2 is provided, ahead of the passage 18 for the needles, and on each side of the slot 19, with a transverse groove 21 and 22, respectively. Arranged in these grooves are guides 23 (see Figs. 11a, which, by means of slots 24 and appropriate screws, can be adjustably rigidly secured to the upper plate 2. These guides 23 have their meeting ends positioned in the area of the slot 19 of the upper plate 2 of the stitch-foot, so that the undersurfaces of these ends prevent the interlocked helical wires fed into the stitch-foot from deviating in a upward direction. These ends of the guides 23 are provided on their upper side with grooves 25 extending in the longitudinal direction of the stitch-foot and which correspond in cross-section to the cross-section of the These guides 23 are so adjusted and fixed in the grooves 21 and 22 that the grooves 25 are positioned accurately above the longitudinally extending threads A A and fastening threads of the fed-in interlocked helical wires. In order to ensure this accurate adjustment each of the guides 23 is provided in one of its lateral edges with a recess 26 in which is engageable the disk-like head 27 (Fig. 4) of a nut adapted to be screwed onto a threaded bolt 28. But it is of course also possible to employ a threaded bolt provided with a similar disk, which bolt may then be screwed into a parallel bore of the upper plate 2.

The mode of operation of the stitch-foot is as follows:

First the two attachment tapes B B are pulled in flatly crossed position through the

recesses

12 and 13, and thereupon in straightened-out positions through the flat space between the upper and lows plates 2 and in the area of the upper surface portion 1a of the lower plate 1. Then the two interlocked helical Wires A A are passed from the forward end through the slot 19, and through the groove 2t? on the underside of the upper plate 2. And then the two guide cords C C are fed from above through the guide grooves 25 and likewise passed slightly deflected through the grooves on the underside of the upper plate 2. Now the sewing of these parts by means of the needles can start, whereby the elements A B C and A B C are in correct positions with respect to each other or above each other, so that the accurate sewing up of these parts can be carried out with great speed.

What I claim as new and desire'to secure by Letters Patent of the United States is:

1. A guide device for use in double-needle sewing machines for the manufacture of helical-wire slide fasteners of the type comprising two interlocked helical wires provided along their opposite outer surfaces with longitudinally extending fastening threads, respective flexible fastening tapes for the wires and guide cords covering the fastening threads, said guide device comprising a lower plate and a plate rigidly secured on the lower plate, said plates being recessed at their meeting surfaces to form a relatively wide horizontal conduit passage having a downwardly facing longitudinal groove at the center of its rear portion, said passage being of a height, at the sides of its rear portion, substantially the same as the thickness of the fastening tapes, and at the center of its rear portion, substantially the same as the combined thickness of the tapes and the guide cords, the passage being substantially greater in height at its forward portion than at its rear portion, whereby the tapes, wires and cords may be fed in angularly separated relationship into said for ward portion, a guide member adjustably mounted in said forward portion, said guide member being formed with crossed guide channels parallel to the plates shaped to slidably receive the respective tapes and guide said tapes in flatly crossed positions, the inner side edges of said channels being spaced apart at their rear ends by a distance less than the width of the groove at the center of the rear portion of said conduit passage, said lower plate being formed rearwardly adjacent said rear ends with two spaced transversely aligned perforations for the passage of the double needles of a sewing machine, said upper plate being formed with a longitudinal slot aligned with the groove at the center of the rear portion of said conduit passage and extending from the forward edge of said upper plate, said slot having a laterally enlarged portion located above said perforations, the width of said slot being otherwise substantially the same as the width of the groove at the center of the rear portion of said conduit passage and being substantially the same as the combined width of the guide cords and the interlocked wires, and further guide means secured on the upper plate over the slot forwardly adjacent said perforations and being formed with upwardly facing longitudinal channels substantially longitudinally aligned with the respective perforations for slidably receiving the guide cords.

2. The structure of claim 1, and wherein the bottom surface of the upper plate is substantially flat at its side portions, and wherein said lower plate is formed at its side margins with upwardly projecting longitudinal ribs which at the rear portion of the bottom plate are substantially the same in height as the thickness of the tapes and which at the forward portion of said bottom plate are at least of a height equal to double the thickness of the tapes, said ribs being spaced apart by a distance substantially equal to the combined widths of the tapes and the interlocked wires.

3. The structure of claim 1, and wherein said guide member comprises a transversely adjustable guide plate and wherein said crossed guide channels comprise groovelike vertically oflset recesses extending from the forward edge to the rear edge of said last-named plate, the inner edges of said last named recesses being oppositely inclined and crossing each other a short distance forwardly of the rear edge of the guide plate.

4. The structure of claim 3, and wherein the groovelike recesses are substantially symmetrically located on opposite sides of the longitudinal center line of the guide plate and wherein said inner edges of the groove-like recesses converge rearwardly from the forward edge of the guide plate.

5. The structure of claim 3, wherein the rear edge of the guide plate is spaced forwardly a substantial distance from the forward edge of the rear portion of said conduit passage.

6. The structure of claim 1, and wherein said upper plate is formed with transverse grooves located forwardly of said perforations, and wherein said further guide means comprises transverse bar members adjustably mounted in said last-named grooves and formed with said upwardly facing longitudinal channels.

References Cited in the file of this patent UNITED STATES PATENTS 2,274,721 Marinsky et a1 Mar. 3, 1942 2,329,991 Kellum. Sept. 21, 1943