EP1464747B1 - Work-clamping device for a sewing machine for bartacking a buttonhole - Google Patents

Description

The invention relates to a Nähgutklammer for a sewing machine for producing a bolt seam on a buttonhole, according to the preamble of claim 1.

Such a Nähgutklammer is known from the legal predecessor Dürkoppwerke GmbH the Applicant and exhibited at an exhibit no. 36 at the IMB-Messe'88 in conjunction with a so-called bolt sewing machine (DÜRKOPP class 570). Here, the operation of the fabric clamp is effected by a lever which is mounted on a rod arranged parallel to the needle bar, which is normally provided for receiving a presser foot. The disadvantage of this is the considerable number of components and the associated costs for the production and assembly.

From the DE 16 85 052 C3 a Nähgutklammer is known in which the drive for the raising and lowering of the presser feet as described above derived from a parallel to the needle bar rod and for moving the presser foot after placement on a clamped workpiece in the sewing plane by a cam operated mechanism becomes. The resulting from the number of components disadvantages also apply to this Nähgutklammer.

From the US 5,609,115 a Nähgutklammer is known in which the raising and lowering of the presser foot by a located on the Nähmaschinenarm actuator and the pushing together of the presser foot for the same takes place in a contraction position by a drive unit in the form of a pneumatic cylinder. The control of the fabric clamp requires some effort.

Finally, out of the US 2,144,763 a Nähgutklammer known in which the buttonhole a comprehensive presser foot after lowering a piece of sewing material are contractible relative to each other. In this, a considerable number of components having Nähgutklammer no symmetrical, carried out by both presser foot contraction movement takes place on the workpiece.

The invention has for its object to provide a fabric clamp, reduces the number of components and the cost of manufacturing and assembly costs are reduced.

This object is achieved by the features in the characterizing part of claim 1. The essence of the invention is to perform the operation of the Nähgutklammer and the execution of a contraction movement on the presser foots via a single lever, which is part of a simple design transmission, which has few and low cost to manufacture components.

Claim 2 indicates an advantageous embodiment, which allows an adjustment of the presser foot position and thus the width dimension of the bar seam to be produced is adaptable. With the embodiment according to claim 3, it is possible to adapt the extent of the contraction movement to be carried out on the presser foot to the respective properties of the work piece.

Fig. 1

eine Vorderansicht einer Nähmaschine mit einer Nähgutklammer,

Fig. 2

eine Explosiv-Darstellung der Nähgutklammer mit ihren Einzelteilen in perspektivischer Ansicht,

Fig. 3

ein Bauteil der Nähgutklammer in einer Draufsicht entsprechend dem Sichtpfeil III in Fig. 2,

Fig. 4

eine Ansicht auf ein Nähgutteil entsprechend dem Sichtpfeil IV in Fig. 1, wobei die Ansicht vergrößert und um 90 Grad im Gegenuhrzeigerdrehsinn gedreht dargestellt ist, und wobei die Ansicht ein in einem Nähgutteil genähtes Knopfloch mit genähter Riegelnaht eines ersten Ausführungsbeispiels darstellt, wobei auf den Nähgutteil aufliegende Sohlenteile in verschiedenen Stellungen dargestellt sind,

Fig. 5

eine der Fig. 4 entsprechende Ansicht, wobei hier an dem Knopfloch eine Riegelnaht eines zweiten Ausführungsbeispiels dargestellt ist und

Fig. 6

eine schematisierte Darstellung von der Nähgutklammer entsprechend der Ansicht von Fig. 1.

The invention is described with reference to the drawing. It shows:

Fig. 1

a front view of a sewing machine with a Nähgutklammer,

Fig. 2

an exploded view of the fabric clamp with its individual parts in a perspective view,

Fig. 3

a component of the Nähgutklammer in a plan view corresponding to the viewing arrow III in Fig. 2 .

Fig. 4

a view of a fabric part corresponding to the viewing arrow IV in Fig. 1 wherein the view is enlarged and rotated by 90 degrees counterclockwise, and wherein the view shows a buttonhole sewn in a fabric part with stitched bar seam of a first embodiment, wherein the sole parts resting on the sole parts are shown in different positions,

Fig. 5

one of the Fig. 4 corresponding view, in which case a bolt seam of a second embodiment is shown here on the buttonhole and

Fig. 6

a schematic representation of the Nähgutklammer according to the view of Fig. 1 ,

The fabric clamp 1 has a bearing plate 2, which is fastened with a screw 3 to a sliding bearing 4. The sliding bearing 4 is part of a sewing machine 5, wherein the sliding bearing 4 is slidably mounted and rotatable in a base plate 6 of the sewing machine 5. The sliding bearing 4 is drivingly connected inside the sewing machine 5 with a feed device. Such a feed device is for example from the U.S. Patent 5,960,731 known and allows the generation of a movement according to a predetermined path.

On the base plate 6, an upwardly extending stand 7 connects, which has an approximately parallel to the base plate 6 extending arm 8, the free end of which forms a head 9. In the head 9, a needle bar 10 is slidably mounted on and off, which has a sewing needle 11 at its end facing the base plate 6. Next, the arm 8 facing top of the base plate 6 is formed as a flat support surface 12 for the fabric clamp 1. The support surface 12 is provided with a stitch hole 13 for the passage of the sewing needle 11. Under the support surface 12, a cooperating with the sewing needle 11 gripper (not shown) is arranged. The sewing needle 11 and the stitch hole 13 are components of a stitch pattern place 14. The structure of the sewing machine 5 described so far is - with the exception of the below described in detail to be fabric clamp 1 - from the above-mentioned sewing machine DÜRKOPP class 570 known.

With a screw 15 and also with the screw 3, a support plate 16 is fixedly connected to the bearing plate 2. The support plate 16 is made of thin sheet steel of 0.8 mm thickness and provided with an opening 17 which surrounds the stitch forming area 14 and allows an unimpeded passage of the sewing needle 11. The made of 3-millimeter thick sheet steel bearing plate 2 has two upwardly angled lobes 18, 19, each with a bore (not designated) are formed, in which an axially fixed by retaining rings 20 is added.

On the axis 20 are further two angled lobes with corresponding holes rotatably mounted as bearing eyes of a U-shaped cross-section having carrier 21, wherein the lobes the tabs 18, 19 of the bearing plate 2 between to record oneself. In Fig. 2 can be seen on the carrier 21 only one of these lobes and referred to as a flap 22.

Further, lobes are still rotatably mounted with corresponding holes of a shift lever 23 on the axis 20. Its rags, of which in Fig. 2 only one can be seen and is referred to as a flap 24, in turn take the lobes 22 of the carrier 21 between them.

The above-described configuration and arrangement is such that the carrier 21 and the shift lever 23 are freely rotatably supported on the axle 20 and guided axially relative to each other on the bearing plate 2.

The carrier 21 is formed with a recess 25 and provided with an angle secured with screws 26 as part of a stop 27, which carries a recorded in a threaded bore and secured with a nut threaded pin 28. Next, the carrier 21 is provided at its free end with a screwed it with screws 29 guide block 30 in which a slot 31 and a groove 32 are formed.

In the groove 32, a web 33 is slidably received, which is part of a control part 34. In the web 33, a threaded bore 35 is formed, in which a slot 31 passing through screw 36 is firmly received. The embodiment is such that the web 33, so the control part 34, in both directions of a double arrow 37 is easily moved back and forth without play. The control part 34 has a plate 38, which has two provided in a symmetrical arrangement to a symmetry axis 39 guide grooves 40, 41. These include between them an angle W of about 2x20 = 40 degrees. Further, the plate 38 is formed in a symmetrical arrangement with four through holes, one of which is referred to as a hole 42. In the groove 40 is movable, however almost free of play a pin 43 received, which is fixedly arranged on a lever 44. This has a free end with a bearing bore (not labeled), through which a firmly screwed into the guide block 30 shoulder screw 45 extends. In the same way, a lever 46 designed as a mirror image of the lever 46 is mounted with a screw corresponding to the shoulder screw 45 on the guide block 30, whereby a pin 46 arranged on the pin also engages in the guide groove 41.

The lever 44 has a free angled end 47, to which a screw 48, a right presser foot 49 is screwed. This is formed with a sole part 50, which in the in Fig. 1 shown position parallel to the support plate 16 is located. Equally, however, mirror-symmetrically, the lever 46 is formed and provided at its free end with a left-hand presser foot 51 screwed thereto, which has a left-hand spoiler 52.

On the plate 38 of the control part 34, arms 53, 54 are each fastened with two screws which extend through the bores 42 and of which one representative is designated as a screw 55. The arms 53, 54 are provided at their ends with bores in which an axially fixed by retaining rings 56 axis is added. The axis 56 extends through holes of two downwardly angled tabs (not shown) which are formed on a switching plate 57. The tabs are axially against the arms 54, 55, so that the switching plate 57 is axially guided. The switching plate 57 is formed with a recess 58 on which an upwardly bent angle 59 is provided with a bore therein. Next, the switching plate 57 is formed with an upwardly angled end 60, which has a recess 61. In the recess 61 an adjusting nut 62 is rotatably received and fixed axially. The adjusting nut 62 is in the recess 61 against falling off held by a bolted to the switch plate 57 locking plate 63 and braked against rotation.

The adjusting nut 62 is provided with an internal thread, in which one end of a threaded rod 64 is received. The adjusting nut 62 and the threaded rod 64 form a length adjuster 62/64. As shown in Fig. 1 the threaded rod 64 protrudes through the hole located in the angle 59. At the free end of the threaded rod 64, a fork-shaped end piece 65 is attached, which has a transverse bore. Through this extends an axis 66. This extends further through located on both sides of the tail 65 spacers 67 by holes of lobes, which are angled to a lever arm 68 of the shift lever 23. In Fig. 2 one of the flaps is referred to as a flap 69. Next is located on the shift lever 23 an angled portion on which a screw not explained in more detail an adjusting lever 70 is screwed. According to Fig. 1 the adjusting lever 70 extends into the interior of the hollow arm 8.

The shift lever 23 has an end 71 with a bore in which the lower end 72 of a threaded rod 73 is received. On the thread of the rod 73, a knurled nut 74 is screwed, on which axially a lower end of a prestressed compression spring 75 in the in Fig. 1 shown supported state. The compression spring 75 is guided radially through a sleeve 77 surrounding the thread. The upper end of the compression spring 75 abuts against a bracket 8 attached to the metal bracket as an abutment 76, in the bore (not labeled), the upper end of the rod 73 is slidably guided.

Finally, the shift lever 23 is still formed with a mounting surface 78 on which screws 79 in the one in the Fig. 1 shown state prestressed leaf spring 80 is attached.

According to the Fig. 1 and 6 the adjusting lever 70 protrudes into the working area of a drive mechanism 81 located in the arm 8 of the sewing machine 5, which is pivotally driven by a force transmitter, wherein a roller 82 is in operative connection with the adjusting lever 70.

The operation of the Nähgutklammer 1 is as follows:

It is assumed that a state in which the lever 70 in the in Fig. 6 shown position 70b is located. This state is achieved by the corresponding actuation of the drive mechanism 81, wherein the shift lever 23 is raised against the force of the prestressed compression spring 75 and pivoted about the axis 20 in the direction of rotation of the clockwise direction. Here take the sole parts 50, 52 of the presser foots 49, 51 in Fig. 6 dash-dotted position shown. The sole parts 50, 52 are thus located in a remote from the support plate 16 rest position.

The shift lever 23 passes here with the threaded pin 28 of the stop 27 to the system, whereby the levers 23 and 21 occupy their positions furthest from each other. Upon reaching this position, a consisting of the switching plate 57, the threaded rod 64 and the forked end piece 65 connecting piece 83 has caused a displacement of the control part 34 relative to the guide block 30, whereby the control part 34 has taken a to the sewing needle 11 remote position. By the action of the guide grooves 40, 41 in conjunction with the pins 43 on the levers 44, 46 take this a position in which the screwed to the levers 44, 46 sole parts 50, 52 are furthest away from each other. Thus, there is a pivoting of the two levers 44, 46 to the respective, screwed into the guide block 30 shoulder screw 45. These opposing movements are in Fig. 4 through the two Arrowheads of a double arrow 84 indicated. Further, the sole parts located away from each other are shown as sole parts 50a and 52a. In this state, ie in the rest position of the fabric clamp 1, there is the insertion of a fabric part 86 provided with a buttonhole 85 which is to be provided with a bar seam 87.

By a switching pulse is a pivoting of the actuating lever 70 and thus initially lowering the remotely positioned sole parts 50, 52 on the fabric part 86, so that it is pressed under the action of the compression spring 75 against the support plate 16. This condition, in which the remote sole parts are located near the platen 16, is referred to as the working position. This state is achieved when the lever 70, the in Fig. 6 shown taken with a dashed line 70a position. With the further pivoting of the actuating lever 70 in the position shown in the regular position, a relative displacement of the control part 34 and the guide block 30 is carried out such that the control part 34 has taken its sewing needle 11 close position. By the interaction of the pins 43 and the guide grooves 40, 41 is a pivoting of the lever 44, 46, whereby the sole parts 50, 52 occupy their positions close to each other. Due to the friction between the sole parts 50, 52 and the fabric part 86, a contraction of the buttonhole 85, so the execution of a contraction movement on the buttonhole 85, which is then secured by a stitching seam 87 to be sewn against tearing.

After sewing the bolt seam 87, in turn, a pivoting of the actuating lever 70, which initially again assumes the position associated with the actuating lever 70a. This results in a sequence of movements in which the control part 34 is displaced into the position located away from the sewing needle, whereby the sole parts 50, 52 occupy again their remote positions. In In this state, the sole parts 50, 52 are still on the Nähgutteil 86 by the force of the lever 21, 23 apart pressing leaf spring 80. Subsequently, a further pivoting of the actuating lever 70 in the initially explained, clarified by the lever 70b position, ie in the state of rest position.

In Fig. 4 It is shown that the longitudinal directions of the buttonhole 85 and the bar seam 87 extend transversely to each other. In Fig. 5 on the other hand, the buttonhole 85 is provided with a bar seam 88 whose longitudinal direction is parallel to that of the buttonhole 85.

How out Fig. 6 As can be seen, the Nähgutklammer 1 is formed with a kinematics, in which the presser feet 49, 51 are spent in various states including the contraction position by a built-gear.

Claims (3)

1. A work piece clamp (1) for a sewing machine (5) with a support plate (16) for a work piece (86) for producing a seam of tack stitches (87; 88) on a buttonhole (85) in the work piece (86), in which said buttonhole extends in a longitudinal direction,
   characterized

   - in that the work piece clamp (1) has a support (21) which is pivotably mounted on an axle (20) that is formed on a sliding bearing (4) of the sewing machine (5);

   - in that two pressure feet (49, 51) with sole parts (50, 52) are mounted on the support (21), the pressure feet (49, 51) being movable on a level parallel to the axle (20) and between them encompassing a portion of the work piece (86) where the seam of tack stitches (87; 88) is located that is to be produced;

   - in that the pressure feet (49, 51), together with the sole parts (50, 52), are movable into a position of rest remote from, and above, the support plate (16) and into a working position close to the support plate (16), the sole parts (50, 52), in the working position, pressing on the work piece (86) that is placed on the support plate (16) by the action of a pre-loaded spring (75, 80);

   - in that in the working position, the pressure feet (49, 51) are movable towards each other crosswise of the longitudinal direction into a position of contraction that contracts the buttonhole (85);

   - in that a drive mechanism (81) comprising a setting lever (70) for moving the work piece clamp (1) into said conditions is provided;

   - in that a shift lever (23) is mounted for rotating pivotably about the axle (20) against the load of a spring (80) that supports itself on the support (21), with the position in which the support (21) and the shift lever (23) are remote from each other, being defined by a stop (27);

   - in that the setting lever (70) is connected to the shift lever (23) which, by way of a joining piece (83), is connected to control means (34) that are displaceably mounted on the support (21); and

   - in that by way of cam connections (40/43, 41/43), the control means (34) are in driving connection with the pressure feet (49, 51) for adjustment of the position of contraction.
2. A work piece clamp according to claim 1, characterized in that the joining piece (83) comprises a length adjustment device (62/64).
3. A work piece clamp according to claim 1 or 2, characterized in that the stop (27) is adjustable.

Images