EP1371770B1 - Buttonhole sewing machine - Google Patents

Abstract

The buttonhole sewing machine has a buttonhole cutter (16) with a cutting blade (26) working with a cutter block. A cutter drive (19) moves the cutting blade and cutting block in relation to each other, with a variable cutting force. It uses a number of linear drives, switched in parallel to each other, and operated selectively by pneumatic forces. The linear drive is a multi-chamber cylinder, with a piston in each chamber, mounted at a common piston rod.

Description

The invention relates to a buttonhole sewing machine according to the preamble of claim 1.

From the DE 33 15 521 C2 (corresponding US 4,552,080 A ), such a buttonhole sewing machine is known. Here, the drive of the cutting block by means of a pneumatically actuated piston-cylinder drive, which is acted upon with different pressure to produce different cutting forces. Furthermore, the cutting speed can be varied. A disadvantage of this known embodiment is that it is very difficult to produce precisely defined cutting forces.

The invention is therefore the object of developing the known buttonhole sewing machine so that the cutting force is adjustable in a simple manner in exactly reproducible form.

This object is achieved by the features in the characterizing part of claim 1. Characterized in that a plurality of parallel connected, pneumatically actuated linear actuators are provided, which can be acted upon optionally with the same pressure, the cutting force can be set or selected in several, each exactly reproducible stages. In this way, a very accurate adaptation to different cutting conditions can be made, which are influenced by the hardness of the material, the type of fabric, the number of fabric layers to be cut, but also by the shape and / or size of the cut to be performed.

In an embodiment according to claims 2 and 3, the linear drives are used as active drives for generating the cutting force.

In the advantageous embodiment according to claims 4 and 5, the linear drives are used passively, d. H. The force limiter formed by them forms depending on the action of the linear drives a more or less flexible abutment for the cutting force generating piston-cylinder drive. The piston-cylinder drive always generates at least the maximum possible cutting force, from which then, if necessary, a part is compensated by the force limiter.

The actuation of the linear actuators via multi-way valves, which can be controlled from a central control unit.

The dependent claims give advantageous developments again.

Fig. 1

eine Knopfloch-Nähmaschine in Seitenansicht,

Fig. 2

einen horizontalen Teil-Schnitt durch die Nähmaschine entsprechend der Schnittlinie II-II in Fig. 1 in gegenüber Fig. 1 vergrößertem Maßstab,

Fig. 3

eine Ansicht auf ein Messer entsprechend dem Sichtpfeil III in Fig. 1,

Fig. 4

einen Amboss in Seitenansicht in gegenüber Fig. 1 vergrößerter Darstellung,

Fig. 5

einen vertikalen Querschnitt durch den Amboss entsprechend der Schnittlinie V-V in Fig. 4,

Fig. 6

eine Draufsicht auf den Amboss entsprechend dem Sichtpfeil VI in Fig. 5,

Fig. 7

einen perspektivisch dargestellten Teil der Knopfloch-Nähmaschine einschließlich der schaltungsmäßigen Verknüpfung der verschiedenen Antriebe mit einer Steuereinheit und einer BedienEinheit,

Fig. 8

eine Draufsicht auf ein in einer Nähgutklammer gehaltenes Nähgutteil mit einem Augen-Knopfloch,

Fig. 9

eine Draufsicht auf ein in einer Nähgutklammer gehaltenes Nähgutteil mit einem einfachen Knopfloch,

Fig. 10

eine Draufsicht auf eine abgewandelte Ausführungsform eines Messers in einer Darstellung entsprechend Fig. 3,

Fig.11

eine Draufsicht auf einen dem Messer nach Fig. 10 angepassten Amboss in einer Darstellung gemäß Fig. 6,

Fig. 12

eine schematische Darstellung eines Schneid-Antriebs für die Knopfloch-Schneid-Vorrichtung einschließlich der schaltungsmäßigen Verknüpfung mit der Steuer-Einheit und

Fig. 13

eine schematische Darstellung einer weiteren Ausführungsform des Schneid-Antriebs der Knopfloch-Schneid-Vorrichtung einschließlich der schaltungsmäßigen Verknüpfung mit der SteuerEinheit.

An embodiment of the invention will be explained in more detail with reference to the drawing. It shows

Fig. 1

a buttonhole sewing machine in side view,

Fig. 2

2 is a horizontal partial section through the sewing machine according to the section line II-II in Fig. 1 in comparison with FIG. 1 enlarged scale,

Fig. 3

a view of a knife according to the viewing arrow III in Fig. 1,

Fig. 4

an anvil in side view in relation to FIG. 1 enlarged view,

Fig. 5

a vertical cross section through the anvil according to the section line VV in Fig. 4,

Fig. 6

a plan view of the anvil corresponding to the viewing arrow VI in Fig. 5,

Fig. 7

a perspective view of part of the buttonhole sewing machine including the circuit-wise connection of the various drives with a control unit and an operating unit,

Fig. 8

a plan view of a held in a fabric clamp workpiece with an eye buttonhole,

Fig. 9

a top view of a workpiece held in a Nähgutklammer Nähgutteil with a simple buttonhole,

Fig. 10

3 a top view of a modified embodiment of a knife in a representation corresponding to FIG. 3,

Figure 11

8 is a plan view of the knife according to FIG. 10 adapted anvil in a representation according to FIG. 6,

Fig. 12

a schematic representation of a cutting drive for the buttonhole cutting device including the circuit connection with the control unit and

Fig. 13

a schematic representation of another embodiment of the cutting drive of the buttonhole cutting device including the circuit connection with the control unit.

1, a buttonhole sewing machine is C-shaped, d. H. it has an upper arm 1, a lower, cabinet-like base plate 2 and a connecting both, approximately vertical stand 3. In the arm 1, an arm shaft 4 is mounted in a conventional manner, which can be driven by a drive motor 5 indicated only in Fig. 7. From the arm shaft 4, the drive of a vertically displaceable needle bar 6 with a needle 7 and a vibratory drive are derived for this purpose in a conventional manner.

On the base plate 2, an xy-table 8 is arranged, which is thus a in two horizontal coordinate directions, namely the x-direction and the y-direction, slidable cross slide. The xy-table 8 is formed in a conventional manner, as for example from the DE 198 07 771 A1 (corresponding U.S. Patent 6,095,066 ) is known. The drive of the xy-table 8 is effected by means of only indicated in Fig. 7 drives, namely an x-drive 9 and a y-drive 10, which are positionable electric motors, so preferably preferably stepper motors, but also controllable DC motors ,

On the xy table 8, a two-part support plate 11a, 11b is arranged. One of the two partial support plates 11a or 11b can be slidably supported on the xy table 8 in the x-direction, while the other partial support plate 11b or 11a immovably, that is fixedly arranged on the xy table 8, which is not shown in detail.

On each part support plate 11a and 11b, a Nähgutklammer 12a and 12b is mounted, each having a mounted on the respective part support plate 11a and 11b partial support plate 13a and 13b, each associated with a clamping plate 14a and 14b is. The clamping plates 14a, 14b are attached to double-armed bearing levers 15a, 15b.

Details of the structure and the drive of the Nähgutklammern 12 a, 12 b result from the DE 102 16 809 A to which reference is made.

As seen in the y-direction behind the needle bar 6 is a buttonhole cutting device 16, which consists essentially of an upper drivable cutting part 17 and a lower anvil 18. The upper cutting part 17 has a cutting drive 19 which will be described in more detail below, one end of which is fastened in the base plate 2 by means of a joint 20. The other upper end of the drive 19 is connected to a two-armed lever 21 by means of a joint 22, which in turn is articulated by means of a further joint 21 a to a drive rod 23 which is guided vertically displaceably in at least one arranged on the arm 1 guide bearing 24 , At the lower end of the drive rod 23, a knife head 25 is mounted, on the underside of a knife 26 shown in FIG. 3 is mounted replaceably. As can be seen in FIG. 3, the knife 26 has a straight cutting part 27 and an eye cutting part 28. The straight cutting part 27 has a length L ₂₇ , while the entire knife 26, consisting of the straight cutting part 27 and the eye cutting part 28 has a length L ₂₆ .

The anvil 18 has a base body 29 which is fixedly arranged in the base plate 2. On the base body 29, a carrier 30 is arranged, which is displaceable in the x direction. It is held by means of strips 31, 32 on the base body 29, wherein the strips 31, 32 are fastened by means of screws 33 on the base body 29. In the main body 29, an adjustment drive 34 is integrated, in which it is a two-sided, pneumatically acted piston-cylinder drive. Its cylinder 35 is formed by a bore extending in the x-direction in the base body 29, which is closed at its ends by means of lids 36. In the cylinder 35, a piston 37 is slidably disposed, at whose end faces in each case a line 38, 39 opens into the cylinder 35, which serves in each case for compressed air supply and for venting. The carrier 30 is connected by means of a bolt 31 a with the piston 37, that is, depending on the application of the piston 37 with compressed air via the line 38 or 39 from the piston 37 in the x-direction. The two displacement movements are limited by adjustable end stops 40, 41, which are formed by arranged in the base body 29 screws.

On the carrier 30, a first cutting block 42 and a second cutting block 43 by means of screws 44, so interchangeable, attached. As can be seen from the overall view of FIG. 3 and FIG. 6, when the first cutting block 42 is located below the knife 26, that is to say cooperates therewith, the entire knife 26, that is to say the rectilinear cutting edge 27 and the eyes Cutting portion 28 with the cutting block 42 into engagement. In contrast, when the second cutting block 43 is under the knife 26, then only the straight cutting part 27 engages with it; the eye cutting part 28 does not cut. The second Cutting block 43 has a recess 43a in the region assigned to the eye-cutting part.

The loading of the adjusting drive 34 and thus the displacement of the carrier 30 in one of the two end positions, in which either the first cutting block 42 below the knife 26 or the second cutting block 43 is located below the knife 26, is carried out by a not shown compressed air source via an electromagnetically actuated multi-way valve 45th

The sewing machine is provided with a control unit 46, via which the x-drive 9, the y-drive 10, the multi-way valve 45 for the adjustment drive 34, the drive motor 5 of the arm shaft 4, not shown clamping drives for the Nähgutklammern 12 a , 12b and the cutting drive 19 are driven. The control unit 46 has a storage part 47. Furthermore, the one operating unit 48 is provided with an input keyboard 49 and a display 50.

The procedure results from FIGS. 8 and 9. After sewing an eyelet-buttonhole seam 51 in a fabric part 52, the fabric part 52 is transported into the cutting device 16 by means of the xy table 8 in the y-direction. The first cutting block 42 is located under the knife 26. The cutting drive 19 is actuated. The entire knife 26 comes into cutting action with the first cutting block 42 forming a mating surface, so that the straight cutting part 27 and the eye cutting part 28 intersect an eye buttonhole 53 having the length L ₂₆ .

If, by contrast, according to FIG. 9, a simple buttonhole, that is to say a buttonhole without an eye and with arbitrary end latches, has been sewn, then the second cutting block 43 is under that by appropriate loading of the adjusting drive 34 Knife 26 brought. The fabric part 52 with the buttonhole seam 54 is moved over the second cutting block 43. By operating the cutting drive 19, only the straight cutting part 27 of the knife 26 comes into cutting contact with the cutting block 43. Only a straight buttonhole 55 with the length L _{27 is} cut.

An alternative results from FIGS. 10 and 11. In this case, the knife 26 'has a middle rectilinear cutting part 27 and at its two ends a respective eye cutting part 28 and 28'. The cutting blocks 42 ', 43' are formed so that the first cutting block 42 'comes into cutting contact only with the straight cutting part 27 and the eye cutting part 28, while the second cutting block 43' is formed so that it only comes into cutting connection with the straight cutting part 27 and the eye cutting part 28 '. This embodiment thus allows the generation of different in their position Augenknopflöchem.

The cutting drive 19 in the embodiment according to FIG. 12 is essentially formed by a multi-chamber cylinder 56, which is fastened by means of the joint 20 in the base plate 2. In it, a piston rod 57 is arranged, whose outer end is connected via the joint 22 with the lever 21. In the cylinder 56, a total of four chambers 58 to 61 separated by partitions 62, 63, 64 from each other, each sealed by the piston rod 57 to be penetrated. The chambers 58 to 61 are thus - in relation to the length of the cylinder 56 - arranged one behind the other. In each chamber, a piston 65, 66, 67, 68 is arranged, which is fixedly connected to the piston rod 57 and sealed relative to the cylinder 56. The chambers 58, 59, 60, 61 with the pistons 65 to 68 thus form four spatially successively arranged, active linear drives. The piston 65 in the first chamber 58 is designed to be acted upon on two sides, via lines 69, 70, that is, the piston rod can be acted upon in the ejection direction 71 or in the insertion direction 72, depending on the application.

The three further chambers 59, 60, 61 are acted upon by means of a common line 73 only in such a way that a force in the extension direction 71 is exerted on the piston rod 57. The three lines 69, 70, 73 are acted upon by three multi-way valves 74, 75, 76, which can be controlled by the control unit 46 by means of the control unit 48.

All pistons 65 to 68 and accordingly also the chambers 58 to 61 have the same diameter; the pressure of the compressed air supplied to them via the valves 74 to 76 is the same, so that the same force is exerted on the piston rod 57, depending on the application of each acted upon piston 65 to 68. A total of four-stage, on the piston rod 57 in Ausschub direction 71 exerted pushing force and thus a force exerted on the knife 26 and 26 'cutting force is exercised in a gradation of 25%, 50%, 75% or 100% of the maximum possible Ausschubkraft , This is done as follows:

When only the piston 65 is acted upon via the line 70 and the valve 75, the piston rod 57 is acted upon in the extension direction 71 by 25% of the maximum possible extension force.

When the pistons 66, 67, 68 are acted upon and the piston 65 is acted upon by the line 69 and the valve 74, the piston rod 57 is acted upon by 50% of the maximum possible extension force in the extension direction 71. This results from the fact that by applying the piston 65 via the line 69, a counterforce is exerted on the piston rod 57 in the insertion direction 72, which results in a partial compensation of the piston 66, 67, 68 in the extension direction 71 Forces leads.

If only the pistons 66, 67, 68 are acted upon via the conduit 73 and the valve 76, then a force in the extension direction 71 is exerted on the piston rod 57 in the amount of 75% of the total possible extension force.

When the piston 65 is acted upon by the line 70 and the multi-way valve 75 and at the same time the piston 66 to 68 via the line 73 and the valve 76 are acted upon, then act on the piston rod 57 100% of the total possible extension force.

For retracting the piston rod 57, ie for lifting the blade 26, 26 'from the anvil 18 after performing a cutting operation, only the piston 65 via the line 69 and the valve 74 is acted upon while the other two lines 70, 73 are vented.

In the alternative embodiment of the cutting drive 19 'shown in FIG. 13, a double-sided pneumatically actuated piston-cylinder drive 77 is provided, the cylinder 78 on the one hand and the piston rod 79 on the other hand are integrated into a toggle mechanism 80. This toggle mechanism 80 is connected on the one hand by means of the joint 22 with the pivot lever 21 and on the other hand supported by means of the joint 20 on a force limiter 81. The cylinder 78 is connected via a multi-way valve 82 and two lines 83, 84 which open on both sides of the piston 85 of the drive 77 in the cylinder 78. Depending on the action on the piston 85 via one of the lines 83 or 84, the pivoting lever 21 is pivoted in such a way that the cutting drive 19 'carries out a cutting movement of the blade 26 or 26' or brings the blade 26, 26 'into its upper rest position returns. When the piston 85 is acted upon by the line 83, the toggle lever mechanism 80 assumes its extended position, whereby a cutting movement is carried out, while when the line 84 is acted upon, the knife 26, 26 'is lifted back into its upper rest position.

A limitation of the force exerted on the pivot lever 21 and thus the knife 26 or 26 'force is effected by the force limiter 81. This has a four-tier abutment 86, which is stationary, ie immovable, supported by a stationary part 87 in the base plate 2. The stationary part 87 of the abutment 86 carries a resilient part 88, on which the toggle mechanism 80 is supported by means of the joint 20. The fixed part 87 is of a frame-like construction and has four pneumatically actuated membrane cylinders 90, 91, 92, 93 as passive linear drives. The resilient part 88 of the abutment 86 also has one above the other intermediate floors 94, wherein in each case an intermediate floor 94 is disposed above an intermediate bottom 89.

The membrane cylinders 90 to 93 are thus each arranged on an intermediate bottom 89 and below an intermediate bottom 94. Each membrane cylinder 90 to 93 has an inner stop 96 below its membrane 95, that is, in its interior. On the membrane 95, an outer stop 97 is attached in each case. The respective outer stop 97 can thus be moved vertically by means of the respective membrane 95.

In a pressureless state, the membranes 95 are in contact with the inner stops 96, while when exposed to compressed air, the outer stops 97 come to rest with a rim 97a on a diaphragm cylinder cover 91a. The design is such that each diaphragm cylinder can only perform a small stroke of, for example, one to two millimeters.

The membrane cylinders 91, 92, 93 are supplied via lines 98, 99, 100 via multi-way valves 101, 102, 103 with compressed air. The diaphragm cylinder 90 is connected to the line 83, which acts on the drive 77.

Depending on whether, in the cutting direction, only the membrane cylinder 90, which is always acted upon at the same time, or even one or two or three membrane cylinders 91 to 93 are acted upon in the cutting direction, an abutment is applied to the toggle mechanism 80 via the joint 20 Force of 25%, 50%, 75% or 100% of the maximum possible abutment force exercised. In turn, this limits the force exerted on the pivoting lever 21.

The magnitude of the forces exerted can be predetermined by a pressure regulator 104, which is likewise controlled via the operating unit 48. A similar pressure regulator can of course also be provided in the embodiment of FIG. 12. Incidentally, in the embodiment according to FIG. 13 too, the actuation of the valves 82, 101, 102, 103 takes place via the operating unit 48.

The purpose of the power grading is to adapt the cutting device 16 to different cutting conditions, such as the hardness of the material, the type of material, the number of layers to be cut, but also the shape and / or size of the material to be cut Cut are affected. In summary, with the adjustment of the cutting force, a flexible cutting condition adjustable cutter 16 is provided in which the knives 26, 26 'and anvil 18 are protected from unnecessary wear by excessive cutting forces, thus significantly increasing operational readiness.

Claims (7)

1. A buttonhole sewing machine, comprising

   - a needle (7) which is drivable in up and down reciprocation;

   - at least one work piece clamp (12a, 12b) which is displaceable in a y direction;

   - a buttonhole cutting device (16),

   -- which is disposed downstream of the needle (7) in the y direction,

   -- which comprises a knife (26, 26'),

   -- which comprises a cutting block (42, 43) that cooperates with the knife (26, 26'), and

   -- a cutting drive (19, 19') for motion of the knife (26, 26') and the cutting block (42, 43) relative to each other by variable cutting force;

   characterized

   - in that the cutting drive (19, 19') includes several linear drives,

   -- which are connected in parallel; and

   -- which are pneumatically actuated selectively.
2. A buttonhole sewing machine according to claim 1, characterized in that the linear drives are multichamber cylinders (56), with a piston (65 to 68) being disposed in each chamber (58 to 61), the pistons (65 to 68) being mounted on a joint piston rod (57).
3. A buttonhole sewing machine according to claim 2, characterized in that at least one chamber (58) is provided with a piston (65) that is bilaterally actuated; and in that three chambers (59 to 61) are provided with pistons (66 to 68) which are jointly actuated unilaterally in the same direction of motion.
4. A buttonhole sewing machine according to claim 1, characterized in that the cutting drive (19') includes a piston-cylinder drive (77) which supports itself against the linear drives that are designed in the form of force limiters (81).
5. A buttonhole sewing machine according to claim 4, characterized in that the force limiter (81) comprises several diaphragm cylinders (90 to 93) as linear drives.
6. A buttonhole sewing machine according to claim 1, characterized in that the linear drives are actuated via multiple-way valve (74 to 76, 82, 101 to 103) which are operated by a central operating unit (48).
7. A buttonhole sewing machine according to claim 1, characterized in that the linear drives are combined in a single constructional unit.

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