US3847097A

US3847097A - Device for making braid openings in cutout pieces of garments

Info

Publication number: US3847097A
Application number: US00452446A
Authority: US
Inventors: A Dusch; P Hintzen
Original assignee: Pfaff Industriemaschinen GmbH
Current assignee: Pfaff Industriemaschinen GmbH
Priority date: 1973-03-20
Filing date: 1974-03-18
Publication date: 1974-11-12
Anticipated expiration: 1991-11-12
Also published as: DE2313717A1; ES424405A1; DE2313717C3; JPS5348132B2; JPS49126456A; GB1461196A; DE2313717B2; IT1020548B

Abstract

The device includes a displaceable workpiece clamp on a twoneedle sewing machine which is pivotable about a pivot axis coinciding with the axis of symmetry of the needles into selected angular positions defined by the displacement direction of the clamp and the longitudinal axis of the sewing machine arm shaft, the sewing machine being lockable in adjusted positions. A guide mechanism is provided for folding a braid strip, and a cutting knife is provided to make a longitudinal slit and works between the two needles, the cutting knife being driven by a drive member included in the sewing machine. A set of individually controllable angle knives are provided for making diverging incisions at the ends of the longitudinal slit. The angle knives are mounted separately from the sewing machine for conjoint rotation about respective axes each of which is parallel to the motion path of the associated angle knife, and a crank and link arrangement connects the angle knives to the sewing machine for positive angular adjustment responsive to pivoting of the sewing machine. A support for the cutting knife is mounted separately from the sewing machine and is slidable on fixed guides. The mounting for the cutting knife support is formed with an elongated slot having generally a figure eight configuration, and the cutting knife drive member extends through this slot and is coupled to the cutting knife support, the arrangement providing for relative movement between the cutting knife support and its drive member.

Description

United States Patent n91 Dusch et al.

[ Nov. 12, 1974 DEVICE FOR MAKING BRAID OPENINGS IN CUTOUT PIECES OF GARMENTS [75] Inventors: Albert Dusch, Kaiserslautern; Peter Hintzen, Krickenbach, both of Germany [73] Assignee: Pfaff lndustriemaschinen Gmbll, Kaiserslautern (Pfalz), Germany [22] Filed: Mar. 18, 1974 [21] Appl. No.: 452,446

[30] Foreign Application Priority Data Primary ExaminerH. Hampton Hunter Attorney, Agent, or FirmMcGlew and Tuttle [57] ABSTRACT The device includes a displaceable workpiece clamp on a two-needle sewing machine which is pivotable about a pivot axis coinciding with the'axis of symmetry of the needles into selected angular positions defined by the displacement direction of the clamp and the longitudinal axis of the sewing machine arm shaft, the sewing machine being lockable in adjusted positions. A guide mechanism is provided for folding a braid strip, and a cutting knife is provided to make a longitudinal slit and works between the two needles, the cutting knife being driven by a drive member included in the sewing machine. A set of individually controllable angle knives are provided for making diverging incisions at the ends of the longitudinal slit. The angle knives are mounted separately from the sewing machine for conjoint rotation about respective axes each of which is parallel to the motion path of the associated angle knife, and a crank and link arrangement connects the angle knives to the sewing machine for positive angular adjustment responsive to pivoting of the sewing machine. A support for the cutting knife is mounted separately from the sewing machine and is slidable on fixed guides. The mounting for the cutting knife support is formed with an elongated slot having generally a figure eight configuration, and the cutting knife drive member extends through this slot and is coupled to the cutting knife support, the arrangement providing for relative movement between the cutting knife support and its drive member.

8 Claims, 7 Drawing Figures PATENTEDHUY 12 m4 sum 2 OF 3 Fig. 2

PATENTEU Nov 12 I974 ME! 3 OF 3 DEVICE FOR MAKING BRAID OPENINGS IN CUTOUT PIECES OF GARMENTS BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a device for making braid openings extending straightly or obliquely to the hem edge of cutout pieces of garments.

To make such braid openings, extending in a straight or oblique direction to the hem edge of a workpiece, there are known devices comprising a two-needle sewing machine with individually disengageable needle bars and equipped with a cutting knife positioned centrally between the two needle bars for making the slit of the braid opening, a pair of angle knives for cutting the angular incisions at the ends of the slit, and a workpiece clamp displaceable relative to the needles.

In devices of this kind, the necessary offsetting of the ends of both seams, in case of a changed oblique position of the braid opening relative to the hem edge of the cutout piece, while maintaining the equal length of the seams, is obtained by a corresponding control of the individually engageable and disengageable needle bars of the sewing machine. To properly orient the diverging angle cuts extending from the end of the slit with respect to the actual oblique position of the braid opening, the wedge-shaped cutting blades of the angle knives are mounted in sets of two on respective knife spikes, for pivotal motion about horizontal hinge pins provided near the tips of the spikes. At its free end, each cutting blade is formed with a control arm. The control arms engage into corresponding recesses of triangular swinging arms which are pivotable about the vertical longitudinal axis of the spikes by means of doublemotion control levers, in accordance with a pre selected oblique position of the braid openings. Thereby, the individual cutting blades are swung, by the control arms which are laterally spaced from the respective axis of rotation of the triangular swinging arms, in mutually opposite directions about their hinge pins fixed near the spike tips so that, in conformity with the oblique position of the braid opening, the two cuts of the angle incision become unequal in length while the depth of penetration of the knife spikes into the workpiece is always the same.

SUMMARY on THE INVENTION The invention is directed to the problem of reducing the costs incurred in the manufacture of complicated devices for making straight and oblique braid openings, and of providing an arrangement permitting, within certain limits, to make braid openings extending at any desired angle to the hem edge of the workpiece.

The problem solved by the invention is to appropriately arrange the angle knives and the central knife, and to provide drive connections, between the sewing machine and the angle knives as well as between the sewing machine and the central knife, such that, when the sewing machine is swung into any angular position relative to the advance direction, the angle knives are automatically brought into a corresponding position while the cutting knife mounted in the center remains in its position aligned with the advance direction, irrespective of the angular adjustment of the sewing machine.

' In accordance with the invention, this problem is solved in that the angle knives are mounted independently of the sewing machine for conjoint pivotal movement about respective axes parallel to their respective paths of motion, and connected to the sewing machine through transmission means effecting positive adjustment of the knives corresponding to the angular adjustment of the sewing machine, and that a support for the cutting knife is mounted separately of the sewing machine for sliding on fixed guide means and is connected to its drive mechanism by coupling means permitting a relative motion between the support of the cutting knife and its drive mechanism.

An object of the invention is to provide an improved device for making braid openings in cutout pieces of garments.

Another object of the invention is to provide such a device in which the cost of manufacture is greatly reduced.

A further object of the invention is to provide such a device including an arrangement permitting the making of braid openings extending at any desired angle to the hem edge of the work piece.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is an end elevational view, partly in section, of a head part of a sewing machine mounted for pivotal movement about a vertical pivot, and illustrating the inventive arrangement of a cutting knife for the slit and a cutting mechanism for the angle incisions at the ends of the slit of a braid opening;

FIG. 2 is a partial top plan view of the sewing machine mounted in a frame;

FIG. 3 is a perspective view of the cutting knife for the slit, mounted on a support;

FIG. 4 is a perspective view of the cutting mechanism for the angle incisions at the ends of the slit;

FIG. 5 shows the position of the angle knives and the location of the angle incisions at the ends of the slit while making a straight braid opening, a portion of the braid strip and the cutout piece being indicated in dashdotted lines;

FIG. 6 shows the position of the angle knives and the location of the angle incisions at one end of the slit while making an oblique braid opening; and

FIG. 7 is a sectional view taken along the line VI]- VII of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. I, a frame 2 is mounted at the bottom side of the table plate 1 of a sewing machine 7 and a bush bearing 4 having a vertical bore 3 is welded thereto. The bore 3 serves to receive a pivot pin 5 which is secured to the base casing 6 of the sewing machine 7.

The sewing machine 7 is a two-needle machine without feed, comprising a pair of pressure feet 9 which are mounted on a pressure bar 8 and adapted to be positioned, under a slight pressure, on the braid strip P at both sides of the raised borders of the latter. Also proularities of the seam forming may be assumed as generally known, a representation of the shuttles and more detailed description of the operational steps connected to the formation of the seams has been omitted.

The sewing machine 7 is driven by a known stop motor 14 which is secured to the base casing 6. With the aid of this motor, and in cooperation with the synchronizer 15 (FIG. 2) fixed to its arm shaft, the sewing machine 7 may be stopped in predetermined positions of the needle bar 10, for example, for cutting the threads at the end of the sewing operation and removing the material without difficulties.

The sewing machine 7 is disposed in an opening 16 (FIGS. 1 and 2) provided in the table plate 1 and mounted for pivotal movement, about pivot pin 5, within certain limits. The limits correspond to the dashdotted lines R and 1.. indicated in FIG. 2. The pivotal axis coincides with the longitudinal axis of the pivot pin 5 and the longitudinal axis of the needle bar 10. For supporting the sewing machine 7, aside-from the bush bearing 4, an arcuate rail 17 (FIG. 2), for rollers 18 mounted on the sewing machine 7, is provided on the frame 2 and secured to the bottom side of the table plate 1.

' A bed plate 20 extending in the advance direction V is screwed to the table plate 1 above the baseplate 19 of the sewing machine 7.

A workpiece clamp 21 (FIG. 2) fixed to the piston rod 22 of an advance unit 23, and represented in the example shown in a very simplified manner, is provided for clamping and displacing the workpiece. The advance unit 23 is secured to a flange 24 which, in the present example, is rigidly connected to a shaft 25 which may be actuated by an hand lever 26 and is rotatably received

intwo bearings

27, 28 mounted on the table plate 1. The shaft 25 is biased by a helical torsion spring 29 whose one end 30 rests against the table plate 1 and whose other end 31 is fixed on the shaft 25. By means of the spring 29, the workpiece clamp 21 is pressed against the bed plate 20.

The advance unit 23 may be operated hydraulicaily or pneumatically and, in a well known manner, in accordance with a control program so that, during the sewing operation, the workpiece clamp 21 is displaced in synchronism withthe stitch formation and, preferably, while condensing the stitches at both ends of the seams for locking the threads, and then brought back continuously into its initial position, in a quick return motion.

For cutting the slit 32 in the cutout garment piece W and in the braid strip P (FIGS. 5 and 7), there is provided, to engage and disengage the workpieces W and P, a cutting knife 33 for operation between the two needles 12. The knife 33 is driven, in a known manner, by the arm shaft of the sewing machine 7 through a vertically reciprocabie moving drive bar 34. During operation, the cutting knife 33 is projected into a slot 35 of the throat plate 36 inserted in the base piate' 19 of the sewing machine 7.

The cutting knife 33 is secured to a support 37 (FIGS. 1 and 3) including a carrier 38 for the knife and a bridge 39. The bridge 39 comprises two donwwardly projecting extensions 40, having external threads and formed with guide bores for

guide rods

42, 43, which are secured to a supporting bracket 41screwed to the table plate 1. v

As shown in FIG. 3, between the two extensions of the bridge 39, a kidney-shaped opening 44 is provided for the knife-driving rod 34 extending therethrough. A coupling ring 46, engaging the bridge from below in the zone of the opening 44, isfixed to the bottom end of drive rod 34 by means of a screw 45. Knife carrier 38 is formed with forked end portions 47 and mounted on bridge 39 by means of adjusting nuts 38,

- 49 screwed to extensions 40, so that forked end portions 47 engage around extensions 40 and knife driving rod 34 can be adjusted, by means of screw 45 and coupling ring 46, vertically without play relative to support 37, and is horizontally displaceable, in conformity with the pivotal motion of sewing machine 7, about pivot pin 5.

Due to this arrangement, during a pivotal movement of sewing machine 7, cutting knife 33 remains aligned in the advance direction V. Thereby, a smooth and neat cutting of the slit 32 is ensured even if braid openings are made extending obliquely to the hem edge of a workpiece.

For folding braid strip P into an inverted T form, and feeding it to the needles 12, a well known guide mechanism 50 (FIG. 1) is provided and mounted at the head side of sewing machine 7.

Two

angle knives

52, 53 are provided for forming the V-shaped angle incisions 51, in cutout piece W and the layer of braid strip P resting immediately thereon, at the ends of slit 32 extending centrically between the two parallel seams 13. Each

angle knife

52, 53 comprises two

blades

58, 59 mounted on respective spikelike portions 54, of

respective knife carriers

56, 57, and the

respective cutting edges

60, 61 of the blades extend obliquely relative to the working direction of the associated knife. Each

blade

58, 59 is engaged, by its forward narrow forked end, into a slot 62, which is provided on the tip of the respectivespike-

like portion

54, 55, and which is open at its side opposite tothe working direction of the knife. Each

blade

58, 59 is fixed against position changes so that its narrow forked end engages over a cross pin 63 projecting from tip of the respective spike-

like portion

54, 55 and its wide end is secured to the latter by means of a screw 64 (FIG. 1).

In the present example, each

knife carrier

56, 57, with the

respective angle knife

52, 53 mounted thereon, is actuated by a respective

pneumatic cylinder

65, 66. Electromagnets might also be used for the same purpose. The carrier 56 of angle knife 52 is fixed to the upper end of the piston rod 67 of pneumatic cylinder 65, and the carrier 57 of angle knife 53 is fixed to the upper end of the piston rod 68 of pneumatic cylinder 66. The top ends of

pneumatic cylinders

65, 66 are secured to the horizontal leg of a supporting angle 69 mounted on frame 2.

Piston rods

67 and 68 extend upwardly through the horizontal legs of angle 69 and are freely movable therein. Two

guide members

70, 71, having a rectangular C-section and legs of unequal length, are mounted so that their legs embrace the horizontal leg of supporting angle 69 and rotatably receive

piston rods

67, 68 extending therethrough.

Respective guide rods

72, 73 for

knife carriers

56, 57 are passed through corresponding bores in

guide members

70, 71 and secured thereto, for example, by brazing, pinning, or screwing.

Each

knife carrier

56, 57 is formed with a respective forked

end portion

74, 75 in which the associated

guide rods

72, 73 are received. This arrangement permits a straight line guidance and conjoint angular adjustment of

knife carriers

56, 57, along with

angle knives

52, 53 about

piston rods

67, 68 of

pneumatic cylinders

65, 66.

At their bottom ends projecting downwardly below the

guide members

70, 71, guide

rods

72, 73 are connected to each other by means of a link 76. A push bar 77 connects guide rod 72 to the stud 78 of a crank 79. Crank 79 is rigidly fixed to pivot pin 5 mounted in base casing 6 of sewing machine 7, so that it follows the pivotal movement of sewing machine 7 about pivot pin 5.

An opening 80 is provided in bed plate permitting

angle knives

52, 53 to pass therethrough, the width of the opening being dimensioned so that, in any adjustable orientation of sewing machine 7,

angle knives

52, 53 are unimpeded in their upward working motion.

Sewing machine 7 is adjustable to any angular posi tion between the end positions designated R and L. To this end, a clamping mechanism is provided comprising a clamp rail 81, secured to the base casing and engaging table plate 1 from below, and a threaded bolt 83 extending through an arcuate slot 82 in table plate 1 and screwed into clamp rail 81. Bolt 83 is made in one piece with a handle 84.

Assuming that sewing machine 7 is stopped in the upper position of the needles and in the middle position, shown in FIG. 2 and intended for making a straight braid openingas illustrated in FIGS, so that the sewing machine is fixed by clamping mechanism 81-84 and workpiece clamp 21 is in its initial position, i.e., removed from bed plate 20 against the action of helical torsion spring 29 and locked in this removed position by appropriate means, the inventive device operates in the following manner.

A cutout piece W (FIGS. 5 and 7), which has been provided with markings for slit 32 of a braid opening and for the angle incisions at the ends of slit 32, is placed on table plate 1 and bed plate 20 in accordance with optical markings, so that the advance direction V of workpiece clamp 21 corresponds to the marking for slit 32 and, consequently, cutting knife 33 for making the slit is aligned with the marking and cutout piece W occupies a definite initial position relative to needles 12.

Braid strip P, having a predetermined length and folded into an inverted T form by guide mechanism 50, is fed below the pressure feet and needles 12, so that cutting knife 33 is positioned between the two raised borders of braid strip P. The pressure feet 9 are then lowered on braid strip P at both sides of the raised borders thereof, and workpiece clamp 21 is brought above the aligned cutout piece W and lowered on the same by means of hand lever 26. Tension spring 29 holds work-- piece clamp 21 down and presses cutout piece W firmly against bed plate 20 so that any unintentional displacement of cutout piece W is prevented and the advance of workpiece clamp 21, along with cutout piece W, is made possible.

As soon as these preparatory operations are completed, sewing machine 7 and advance unit 23 are started. While sewing machine 7 is running, the movement of workpiece clamp 21 is controlled, preferably step-by-step in synchronism with the stitch'formation, by supplying pressure fluid through the connections of the double-acting working cylinders of advance unit 23 so that, initially, the two threads are locked at the starting end of seams 13 by condensing the stitches or by a temporary reversal of the advance direction and then the two seams 13 are sewn.

A programmed control of the individual mechanisms of the device can be effected in various ways, for example with the aid of fixed switches arranged in rows and actuated by corresponding rows of trip cams which may be provided on a supporting plate secured to workpiece clamp 21. In this case, a selector switch may be provided, by means of which the different switches or rows of trip cams are preparatorily selected, for example for making braid openings of unequal lengths.

Another possibility is to use a control cylinder carrying carns for actuating the corresponding switches and connected to the drive of the sewing machine. Particularities of an electric control may be dispensed with, since such a control is wellknown and does not constitute an object of the present invention.

After the seam length necessary for the formation of the first angle cut 51 has been sewn, cutting knife 33 is engaged. In operation, cutting knife 33 is projected into slot 35 of throat plate 36 and, during the sewing, cuts central slit 32 extending between the two seams 13 and also the layer of folded braid strip P reposing directly on cutout piece W.

In the further sewing operation, the first angle knife 52 is actuated at the respective point by admitting compressed air into the pneumatic cylinder 65, so that angle knife 52, whose carrier 56 is fixed to piston rod 67 of pneumatic cylinder 65, moves through opening in bed plate 20 upwardly and, during this motion, forms the first angle cut 51 in cutout piece W and the layer of folded braid strip P reposing immediately thereon. The finished angle cuts extend from the ends of slit 32 in a V-form up to the ends of the parallel seams 13.

Angie knife 52 may be returned into its initial position either by means of a return spring or by admitting compressed air through a second connection. Cutting knife 33 is disengaged at the point provided for the second angle cut, the seams are finished up to the predetermined length and locked, the threads are cut during the last upward motion of needle bar 10, the pressure feet 9 are lifted, and sewing machine 7 is stopped.

To effect the second angle cut, workpiece clamp 21, along with cutout piece W and braid strip P sewn thereon, is moved past the second angle knife 53 and stopped at the provided point. Compressed air is admitted through a connection into pneumatic cylinder 66, whereby the angle knife 53, mounted on carrier 57 which is fixed to piston rod 68 of pneumatic cylinder 66, is moved upwardly through opening 80 and, during this motion, the second angle incision is cut into cutout piece W and the immediately adjacent layer of folded braid strip P, whereupon angle knife 53 and its carrier 57 are returned to their initial position by means of a 7 return spring orby admitting compressed air through another connection of pneumatic cylinder 66.

Finally, after lifting'workpiece clamp 21 against the action of torsion spring 29 by means of hand lever 26, the cutout piece W,'with the braid strip P sewn thereon, is removed, and the braid strip is turned through slit 32 to the inside ofcutout piece W.

For making a braid opening extending obliquely to the hem edge of a cutout piece, as shown in FIG. 6, where the sequence of operations is the same as in the case of straight braid openings, clamping mechanism 81-84, locking the sewing machine in its middle position M (FIG. 2), is disengaged and sewing machine 7 is pivoted about an axis coinciding with the longitudinal axis of pivot pin 5 and the longitudinal axis of the needle-bar into a position indicated by the line L (FIG. 2),

where the longitudinal axis of the arm shaft of sewing machine 7 coincides with the line L.

in this position, the sewing machine 7 is locked in the frame by means of clamping mechanism 8l84. If desired, sewing machine 7 may. be locked in any position within the pivotal zone limited by lines R and L. To facilitate the exact positioning, table plate 1 may be provided withappropriate markings adjacent arcuate slot 82, as indicated in FIG. 2.

Because the advance direction V of the workpiece clamp 21 is always the same, the result of the swinging of sewing machine 7 is that the end points of the seams 13, having equal lengths, are automatically offset by a distance corresponding to the respective oblique position of the braid opening.

While pivoting sewing machine 7 about pivot pin 5, kidney-shaped opening 44, through which knife-driving rod 34 extends, makes possible a relative movement between the latter, which is mounted for up-and-down motion in the head of the sewing machine-and laterally spaced from needle bar forming the axis of. rotation of the machine, and, consequently, pivoted along with the machine, and support 37 of cutting knife 33, which is slidable on fixed

guide rods

42, 43. The center offset between support 37 and knife-driving rod 34, produced by the pivoting of sewing machine 7 about pivot pin 5, is thereby compensated.

Due to this and to the mounting of support 37 of cutting knife 33 on fixed

guide rods

42, 43 separated from the sewing machine, cutting knife 33 keeps its constant alignment with the advance direction while maintaining the coupling connection between support 37 and knifedriving rod 34 so that, even in non-central positions of the sewing machine, slit 32 is cut in a smooth and neatv manner.

For making the angle incisions 51 at the two ends of slit 32, it is important that these incisions extend from the very ends of slit 32, cut centrally between the two seams 13, close up to the seams so that, after the turning of braid strip P sewn thereon, the angles at the ends of the braid openings have a correct aspect and an exact angular form.

While, in straight braid openings, the angle incisions have sides equal to each other, in oblique braid openings, these sides are of unequal length because of the offset end points of the two seams 13.

In order to be able to adjust the position of the separately mounted

angle knives

52, 53 to the different positions of the machine relative to the advance direction V of workpiece clamp 21, for making braid openings ,ted to

carriers

56, 57 of the respective angle knives 52,

53 due to the fact that

guide rods

72, 73 are connected to each other by link 76 and that the forked

end portions

74, 75

embrace guide rods

72, 73.

At the same time,

carriers

56, 57 of angle knives S2,

53 are turned about the respective longitudinal axes of their drive means (piston rods 67, 68) so that, within the provided pivotal range of sewing machine 7, cutting

edges

60, 61 of the

different blades

58, 59 of

angle knives

52, 53 execute cuts extending from the ends of slit 32 close up to the end points of seams I3 and corresponding to the offset position of the end points of the two seams 13, which offset position is produced by the pivoting of the sewing machine and depends on the desired angular position of the sewing machine relative to the advance direction V. This is the condition for a sharp and distinct formation of the angles at the ends of a braid opening after turning of braid strip P sewn thereon and for an impeccable aspect ofthe braid opening.

It is evident that, after the disengagement of clamping mechanism 81-84, sewing machine 7 canbe swung about pivot pin 5 without any difficulties and locked again within the provided range in any position. Cutting knife 33 reamins, in any case, aligned in the advance direction, whereby straight and smoothly cut edges are obtained.

Knife support 37 is designed so that the center offset between knife driving rod 34 and support 37, produced by the pivotal movement of sewing machine 7,. is compensated. Also,

angle knives

52, 53 adapt themselves automatically to any oblique position of sewing machine 7 relative to the advance direction. Thus, the device can be used for making straight as well as oblique braid openings. The changeover to the respective desired oblique position can be effected without any difficulty. Therefore, it is irrelevant in which sequential order the straight and oblique braid openings are made on lefthand and righthand cutout pieces of garments such as, for example, jackets. For controlling the machine in all provided positions, a single basic program, needed in any case for making a braid opening, is sufficient.

Since the two

angle knives

52, 53 are controllable independently of each other and the instant of engaging or disengaging of cutting knife 33 for slit 32 may also be freely chosen, the device can be used for making braid openings of different lengths.

If necessary, workpiece clamp 21 can be equipped with a holder for a pocket flap for making braid pocket openings with flaps.

While a specific embodiment of the invention has been described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. In a device for making braid openings, extending either straightly or obliquely to the hem edge of cutout pieces of a garment, of the type including adisplaceable workpiece clamp, on a two-needle sewing machine which is pivotable about a pivot axis, coinciding with the axis of symmetry of the needles, into selected angular positions, defined by the displacement direction of the workpiece clamp and the longitudinal axis of the sewing machine arm shaft, and lockable in these positions, a folding guide mechanism for a braid strip, a cutting knife, for making a longitudinal slit, working between the needles, a drive memberfor the cutting knife included in the sewing machine, and a cutting mechanism, including a set of individually controllable angle knives, for making diverging incisions at the ends of the longitudinal slit: the improvement comprising, in combination, means mounting said angle knives separately from said sewing machine for conjoint rotation about respective axes each of whichis parallel to the motion path of the associated angle knife; transmission means connecting said angle knives to said sewing machine for positive angular adjustment of said angle knives responsive to such pivoting of said sewing machine; a support for said cutting knife; means mounting said support separately from said sewing machine; fixed guide means slidably engaging said support; and coupling means connecting said cutting knife support to said cutting knife drive member and providing for relative movement between said support and said drive member.

2. In a device for making braid openings, the improvement claimed in claim 1, including respective drive means for said angle knives; said angle knives being mounted on their respective drive means for rotation about the longitudinal axes of the respective drive means extending in the working direction; respective guide rods extending parallel to and spaced from each drive means; said angle knives having respective forked end portions each engaged with a respective guide rod; said guide rods being fixed in respective guide members and said guide rods, together with their respective guide members, being pivotal about the longitudinal axes of the respective drive means; a link interconnecting said guide rods; said sewing machine being secured to a pivot pin for such pivoting about its pivot axis; a crank secured to said pivot pin; and a further link connecting one guide rod to said crank.

3. In a device for making braid openings, the improvement claimed in claim 1, in which said fixed guide means engaging said cutting knife support comprises guide rods slidably engaging said suppor't; said support including a bridge member formed with a kidneyshaped opening receiving said cutting knife drive memher; and a coupling ring secured to said drive member beneath said bridge member and coupling said bridge member to said drive member while providing, in conjunction with said kidney-shaped opening, for movement of said bridge member horizontally relative to said drive member.

4. In a device for making braid openings, the improvement claimed in claim 3, including extensions projecting downwardly from said bridge member and formed with respective bores each receiving a guide rod; said extensions being externally threaded for engagement by respective adjusting nuts operable to adjust said cutting knife support.

5. In a device for making braid openings, the improvement claimed in claim 4, in which said cutting knife support further includes a cutting knife carrying member engaging the underside of said bridge member and having forked ends embracing said extensions; the height of said knife carrying member being adjustable by said adjusting nuts threaded onto said extensions.

6. in a device for making braid openings, the improvement claimed in claim 5, in which said drive member is a drive rod having a threaded bore in its lower end; and a screw extending through said coupling ring and threaded into said bore.

7. In a device for making braid openings, the improvement claimed in claim 2, in which each angle knife carrier comprises a spike-like portion having slot guides on a wedge-shaped tip, said slot guides being open at the side thereof opposed to the working direction of the associated angle knife; said slot guides receiving the respective forward ends of the individual blades of said angle knives.

8. In a device for making braid openings, the improvement claimed in claim 7, including cross pins on each spike-like portion securing the individual blades in position.

Claims

1. In a device for making braid openings, extending either straightly or obliquely to the hem edge of cutout pieces of a garment, of the type including a displaceable workpiece clamp, on a two-needle sewing machine which is pivotable about a pivot axis, coinciding with the axis of symmetry of the needles, into selected angular positions, defined by the displacement direction of the workpiece clamp and the longitudinal axis of the sewing machine arm shaft, and lockable in these positions, a folding guide mechanism for a braid strip, a cutting knife, for making a longitudinal slit, working between the needles, a drive member for the cutting knife included in the sewing machine, and a cutting mechanism, including a set of individually controllable angle knives, for making diverging incisions at the ends of the longitudinal slit: the improvement comprising, in combination, means mounting said angle knives separately from said sewing machine for conjoint rotation about respective axes each of which is parallel to the motion path of the associated angle knife; transmission means connecting said angle knives to said sewing machine for positive angular adjustment of said angle knives responsive to such pivoting of said sewing machine; a support for said cutting knife; means mounting said support separately from said sewing machine; fixed guide means slidably engaging said support; and coupling means connecting said cutting knife support to said cutting knife drive member and providing for relative movement between said support and said drive member.

3. In a device for making braid openings, the improvement claimed in claim 1, in which said fixed guide means engaging said cutting knife support comprises guide rods slidably engaging said support; said support including a bridge member formed with a kidney-shaped opening receiving said cutting knife drive member; and a coupling ring secured to said drive member beneath said bridge member and coupling said bridge member to said drive member while providing, in conjunction with said kidney-shaped opening, for movement of said bridge member horizontally relative to said drive member.