EP1837430A1 - Needle bar holder for a sewing machine - Google Patents

Abstract

The needle clamp (7) for receiving sewing needle (4) to firmly hold the needle on a needle bar (2) in a stop position, useful for an industrial sewing machine (1), comprises a device arranged on the needle clamp for manually adjusting the stop position of the clamp in a direction transverse to the sewing needle, and a relative position of the needle in relative to needle guard, and/or a gripper (6), which serves to grip threads conveying by the needle, and storage device that is adjustably arranged transverse to the needle and also to hold the needle. The needle clamp (7) for receiving sewing needle (4) to firmly hold the needle on a needle bar (2) in a stop position, useful for an industrial sewing machine (1), comprises a device arranged on the needle clamp for manually adjusting the stop position of the clamp in a direction transverse to the sewing needle, and a relative position of the needle in relative to needle guard, and/or a gripper (6), which serves to grip threads conveying by the needle, and storage device that is adjustably arranged transverse to the needle and also to hold the needle. The adjusting device has a position-adjustable device, a clamping unit to clamp the needle against the position-adjustable device, and an electrically controllable and/or adjustable drive. The adjustable device is constituently formed to needle stop positions, in which the needle is to hold parallel to a needle-movement direction that is determined by the needle movement. The adjusting device is arranged to position adjustment in adjustable release or infinitely adjustable manner.

Description

The invention relates to a needle holder for a sewing machine, in particular for an industrial sewing machine. For sewing machines, the sewing needle, needle plate, gripper and needle guard must be accurately positioned with respect to each other to ensure reliable stitching, especially when sewing at high sewing speed and thus high number of stitches. If the adjustment of the position of the gripper with respect to the needle is inadequate, this may result in missed stitches, needle and thread breaks as well as damage to the gripper and needle guard.

Sewing machine needles are selected in particular with regard to their thickness with respect to the sewing material. Accordingly There is a need to use one and the same sewing machine, different thickness sewing needles.

Sewing machine needles have a groove in the vicinity of their eye, into which the gripper dips when stitching to receive a thread pierced by the sewing material. Different thick sewing needles have different deep grooves. The bottom or bottom of the groove thus has different positions with different thickness sewing machine needles.

This is from the DE 103 34 023 A1 which discloses a system for producing needles of different thicknesses. When using these sewing needles, the gripper position does not have to be matched to the particular needle thickness used. The application of the doctrine of DE 103 34 023 In the case of needles with a large needle diameter in the region of the groove, this leads to a small needle cross section in comparison to the needle cross section in the area of the needle shank. This increases the susceptibility to breakage, especially in needles with a large needle diameter (Nm).

In household sewing machines needles are provided to circumvent the gripper adjustment, which have a flattened piston. The flattening is formed differently with different strength sewing machine needles (needles with different nominal diameter) to ensure that no gripper adjustment is required when different thickness needles are used. In industrial sewing machines, however, needles are generally required with a cylindrical piston. Thus, the needle holder uniformly sets the central axis of all sewing needles.

The adjustment of a gripper to adapt to sewing needles with different thickness is usually associated with a lot of work and also requires a skilled specialist. In particular, in lockstitch machines with vertically arranged gripper axis readjustment of the gripper and the needle guard is quite expensive, resulting in downtime and high Einrichtaufwand.

On this basis, it is an object of the invention to provide a way to use on sewing machines, especially industrial sewing machines, needles with different needle size, without having to adjust the gripper.

This object is achieved with the needle holder according to claim 1:

The needle holder has a holding device for receiving a sewing needle in order to hold it in a holding position. On the holding device, an adjusting device is provided, with which the holding position of the holding device in a direction transverse to the sewing needle and thus also transversely to the needle bar is adjustable. This can ensure that each different sewing needles are positioned so that the bottom of their groove comes to rest in one and the same relative position with respect to the cooperating with the sewing needle gripper. The adjustment of the needle position is usually much easier than the setting of a gripper position. The needle is freely accessible above the sewing table. The adjustment of the needle position is thus similarly easy to carry out, such as the replacement of the needle.

Due to the transverse adjustment of the needles, this has no defined zero position. It may therefore be necessary to use throat plates with different stitch hole positions. However, a needle plate change is easily feasible even for less experienced employees.

Sewing machines are also known in which the needle is inserted into a bore which is contained in the means for ensuring that the material is being transported. These sewing machines do not contain a taphole plate. The bore is shaped so that an adjustment of the position due to a needle change is not necessary.

In the case of the needle holder according to the invention, the sewing machine needle can be displaceably arranged relative to the actual needle bar on which the sewing needle is held and which is moved vertically up and down during sewing operation, so that the needle is moved toward the gripper to or away from the gripper can. The gripper position can remain unchanged.

In a first embodiment, the adjusting device may comprise a clamping device with which the piston of the sewing needle is tensioned against a positionally adjustable abutment means. A position adjustment of the attachment means can be carried out, for example, in stages or steplessly in order to clamp the sewing needle in their respective desired position. The adjusting device has an adjustable element on which the sewing needle rests (then the element forms a contact means) or which holds the sewing needle (then the element forms a holding means). The adjustable element can also be designed in the form of interchangeable supplements. All mentioned alternatives are suitable for the realization of the invention.

Ideally, with stepless position adjustment it is possible to set the optimal needle-gripper distance for any needle size. In many cases, however, only needles are used with a predetermined strength anyway. In such cases, it is sufficient if the needle holder allows adjustment positions for needles of the corresponding needle size. Furthermore, it is possible to limit the adjustment options to steps of, for example, 0.1 mm to 0.2 mm. For example, a mechanical adjustment device may be provided with a locking dimension that is a predetermined size of e.g. 0.2 mm. The needles can be divided into several, for example four, groups. Group 1 can include needles with a diameter of Nm 80, 90, 100. Group 2 includes needles of diameter Nm 110, 120, 130. Group 3 includes needles of Nm 140, 150, 160. Group 4 then includes, for example, needles of Nm 180, 190, 200. A mechanical four-position adjustment device can handle all significant needle sizes Groups 1 to 4 cover, each adjustment is assigned to each of the groups. This takes into account most precision requirements that occur in practice.

It is possible to make the adjustment manually. The corresponding manual adjustment devices are preferably Stufenverstelleinrichtungen. Incorrect settings are thus easily excluded. The operator only has to select the correct detent level or setting level. The adjustment can be done by a switching shaft, raster circuit, series connection or by using appropriate supplements. Likewise, it is possible to electronically adjust the distance of the sewing needle to the gripper by means of piezo technology, ie piezo drives or servomotors. An electronic Control is particularly advantageous because it can be reproducibly obtained by them desired machine settings.

Ideally, each needle thickness is assigned exactly one position of the sewing needle or the adjusting device and thus achieved that the optimum gripper spacing is maintained. In the case of an electronic control a stepless adjustment is advantageous.

Further details of advantageous embodiments of the invention will become apparent from the drawings, the description or claims.

Figur 1

eine Nähmaschine in einer schematisierten, ausschnittsweisen Darstellung,

Figur 1a

eine Nähnadel der Nähmaschine nach Figur 1 in ausschnittsweiser Darstellung und in einem anderen Maßstab,

Figur 2

eine Nadelstange mit Nadelhalter und Rastwelle zur Verstellung der Nadelposition in schematisierter Vertikalschnittdarstellung,

Figur 3

den Nadelhalter nach Figur 2 in einer anderen Vertikalschnittdarstellung, wobei die Schnittfläche in einem 90°-Winkel zu der Schnittfläche gemäß Figur 2 steht,

Figur 4

den Nadelhalter nach Figur 2 und 3 in einer Horizontalschnittdarstellung,

Figur 5

eine abgewandelte Ausführungsform des Nadelhalters für die Nähmaschine nach Figur 1,

Figur 6

den Nadelhalter nach Figur 5 in einer Horizontalschnittdarstellung,

Figur 7

eine weiter abgewandelte Ausführungsform des Nadelhalters für eine Nähmaschine nach Figur 1 in schematisierter Seitenansicht,

Figur 8

den Nadelhalter nach Figur 7 in einer Stirnansicht,

Figur 9

den Nadelhalter nach Figur 7 im Horizontalschnitt,

Figur 10

eine abgewandelte Ausführungsform des Nadelhalters für eine Nähmaschine nach Figur 1 und

Figur 11

eine weitere abgewandelte Ausführungsform des Nadelhalters für die Nähmaschine nach Figur 1 in schematisierter Seitenansicht.

In the drawings, embodiments of the invention are illustrated. Show it:

FIG. 1

a sewing machine in a schematized, fragmentary representation,

FIG. 1a

a sewing needle of the sewing machine of Figure 1 in a sectional view and on a different scale,

FIG. 2

a needle bar with needle holder and latching shaft for adjusting the needle position in a schematic vertical sectional view,

FIG. 3

the needle holder of Figure 2 in another vertical sectional view, wherein the sectional area is at a 90 ° angle to the sectional surface of Figure 2,

FIG. 4

the needle holder of Figure 2 and 3 in a horizontal sectional view,

FIG. 5

a modified embodiment of the needle holder for the sewing machine of Figure 1,

FIG. 6

the needle holder of Figure 5 in a horizontal sectional view,

FIG. 7

a further modified embodiment of the needle holder for a sewing machine according to Figure 1 in a schematic side view,

FIG. 8

the needle holder of Figure 7 in an end view,

FIG. 9

the needle holder of Figure 7 in horizontal section,

FIG. 10

a modified embodiment of the needle holder for a sewing machine of Figure 1 and

FIG. 11

a further modified embodiment of the needle holder for the sewing machine of Figure 1 in a schematic side view.

FIG. 1 schematically illustrates a section of a sewing machine 1 on the basis of a needle bar 2 of a table 3 belonging to the sewing machine 1, a sewing needle 4, a foot 5 and a gripper 6. The illustrated gripper 6 is an alternating gripper 6 with a horizontal axis of rotation. The representation of an alternating gripper 6 is chosen by way of example, the same applies to rotating gripper. The sewing needle 4 is attached to the needle bar 2 by means of a needle holder 7. The needle bar 2 is connected to a drive device and, as schematically illustrated in Figure 1 by an arrow 8, reciprocally driven. It performs a linear movement along the longitudinal direction of the sewing needle 4. In other words, the sewing needle 4 is oriented parallel to the needle bar 2 and its direction of movement. The sewing needle 4 has at its upper end a cylindrical portion which will be referred to as a piston and the attachment of the sewing needle 4 is used. The piston is arranged concentrically with the remaining sewing needle 4, and has a diameter which corresponds to that of the sewing needles 4 used. All sewing needles 4, which are associated with a sewing machine and its needle bar 2, have the same piston diameter regardless of their thickness.

The foot 5 has a slot 60 which can be pierced by the sewing needle 4. The substance transport serving, arranged below the foot 5 means are not illustrated. Under the foot 5, a tap hole plate 9 is further arranged, which has an opening 10 to be pierced by the sewing needle 4. Under the taphole plate 9 sit the movably arranged gripper 6, which has a tip 6a, and a needle guard 11, on which the flank of the needle tip can be supported when the needle 4 in the area their lower reversal point moves. This leads to a stabilization of the transverse movement of the sewing needle 4. The transverse movement of the sewing needle 4, which is undesirable in itself, depends on the sewing conditions, the sewing process. Does the sewing needle no transverse movements, or they are equalized by the needle guard 11, this facilitates the gripper 6 to grab the thread. In this case, the gripper 6 enters a provided on the sewing needle 4 groove 12 to take a current through her eye 13 thread.

The sewing needle 4 is illustrated separately in FIG. 1a. The eye 13 is disposed adjacent to its tip 14. A needle groove 15 or yarn channel opens into the eye 13. At the needle groove 15 opposite side, the groove 12 is arranged. The sewing needle 4 and the gripper 6 are moved with respect to each other so that the tip 6a of the gripper 6 grips into the groove 12 while the bottom of the same just not or at most touches with low pressure.

The needle holder 7 allows the storage of different thickness sewing needles with uniform cylindrical. Pistons and their positioning on the needle bar 2, so that despite different needle thickness, the bottoms of the flutes 12 different thickness needles with respect to the gripper 6 are at a uniform position. The needle holder 7 used for this purpose is illustrated separately in Figure 2 in vertical section. It forms, for example, a cuboid housing, on the upper side of which an extension 61 is provided with a threaded blind bore. The extension 61 can be received by an end-side stepped bore which is formed in the needle bar 2. To connect between needle bar 2 and needle holder 7 is a screw 16th

The needle holder 7 encloses an inner space 17, in which a slider 18 is mounted transversely to the longitudinal direction of the needle bar 2 as well as transversely to the longitudinal direction of the sewing needle 4 adjustable. The adjustment direction is indicated in Figure 2 by an arrow. The slider 18 forms a bearing device 19 for the sewing needle 4. As Figure 3 illustrates, it engages with a web 20 provided on the underside of the needle holder 7 slot 21. At the end of the needle holder 7 out end is a blind bore 22 for receiving the Piston of the sewing needle 4 is provided. One or more of these blind bore 22 in the transverse direction cutting threaded holes 23 serve to receive clamping screws for locking the sewing needle. 4

The slider 18 is biased by a clamping means, for example in the form of a spring means, in particular in the form of a compression spring 24, in an adjustment direction and pressed against a bearing means 25. This is formed in this embodiment by a detent shaft 26 which has two or more, e.g. four, locking positions, which are defined by flattened side surfaces accordingly. The distances of these side surfaces of a rotation axis 27 are of different sizes. The latching shaft 26 is arranged transversely to the needle bar 2 and the sewing needle 4 and protrudes with one end out of the needle holder 7. As illustrated in FIG. 4, a handle, for example in the form of a setting wheel 28, may be arranged at the end. The substantially flat side surfaces of the latching shaft 26 are parallel to the axis of rotation 27, which in turn is arranged parallel to a flat side surface 29 of the slider 18.

The compression spring 24 or any other suitable clamping means and the abutment means 25 form an adjusting device 30 for adjusting the transverse position of the slider 18 with respect to the longitudinal axis of the needle bar 2 and thus an adjustment for the sewing needle 4. The adjusting device 30 operates as follows:

It is assumed, for example, that the four substantially planar side surfaces of the approximately rectangular detent shaft 26 are arranged at intervals to the axis of rotation 27, which differ from each other by 0.2 mm. These differences are exaggerated in Figure 2 for illustrative purposes. The needle holder 7 is suitable, for example, for storing and holding sewing needles of diameter Nm 80 to diameter Nm 200. For example, the needles of Nm 80 to Nm 100 in a first group, from Nm 110 to Nm 130 in a second group of Nm 140 to 160 Nm in a third group and from Nm 180 to Nm 200 in a fourth group. The operator now selects a suitable sewing needle from one of the four groups and sets the locking position of the locking shaft 26 accordingly. The position of the latching shaft with respect to the four groups of needles can be done, for example, by means of four markings provided on the outside of the needle holder 2 or on the setting wheel 28. If the setting is made, the sewing needle is clamped in the blind bore 22. If necessary, the throat plate 9 can be adjusted or replaced. A gripper adjustment is not required. It can thus be started after needle replacement and adjustment of the adjustment 30 with the sewing operation.

Figures 5 and 6 illustrate a modified embodiment of the needle holder 7, in which the adjusting device 30 does not require storage device 19. This will be explained below, supplementing the previous description is true, as far as the same reference numerals are used and nothing to the contrary is carried out.

In the interior 17 of the needle holder 7, a rotatably mounted receiving prism 31 is mounted. This has at its periphery three, four or more each of two preferably flat bearing surfaces 32, 33 limited recesses, where a guided through a hole in the interior 17 end of the sewing needle 4 plant. The contact surfaces 32, 33 are oriented in an example at right angles to each other. The contact surfaces 32, 33 opposite a threaded bore 34 is arranged in the housing of the needle holder 7, in which a clamping screw 35 is seated. This serves to clamp the shaft or piston of the sewing needle 4 against the abutment means, the prism 31.

The prism 31 is rotatably supported by a shaft 36 in the needle holder 7 about the rotation axis 27, which is oriented transversely to the sewing needle 4, and whose end protrudes from the needle holder 7 out and the setting wheel 28 carries. In addition, the shaft 36 is longitudinally adjustable against the force of a spring 37 or other suitable clamping means. The prism 31 of the shaft 36 or the adjusting wheel 28 may also be associated with a locking device 38 which is formed in the simplest case, as illustrated, by a detent pin 39, the different, around the shaft 36 arranged around detent holes 62 are assigned.

The prism 31 has in the present embodiment, four contact surface pairs. In FIG. 6, the shank of the sewing needle 4 lies against the abutment surfaces 32, 33. Further abutment surface pairs are, for example, 40, 41 and 42, 43, respectively, of the abutment surfaces educated. Only three contact surface pairs can be seen from FIG. The embodiment actually contains 4 of these contact surface pairs. The respective abutment surface pairs define different abutment positions for the shank of the sewing needle 4 by being positioned differently with respect to the axis of rotation 27.

To change the needle thickness, first the clamping screw 35 is released and the sewing needle 4 is removed. Then, the thumbwheel 28 is pulled pulling in the axial direction to bring out the pin 39 from its bore. Once it is free, the setting wheel 28 can be rotated to the desired locking position, which corresponds to the needle size to be used now. If the thumbwheel 28 is released, the spring 37 pushes the shaft 36 back to its original position, wherein the pin 39 moves into a corresponding other bore 62.

In the new locking position now another contact surface pair is arrived at the clamping screw 35 facing point. It is now the sewing needle 4 is inserted with the desired needle size in the space between the respective contact surfaces and the clamping screw 35 and tightened the clamping screw 35. Now the sewing process can be started or continued.

Figures 7 to 9 illustrate a further embodiment, which also has more locking positions. With the exception of the special features explained below, the above description of the figures applies correspondingly to the embodiment according to FIGS. 7 to 9 on the basis of the same reference numbers.

In the interior 17 of the needle holder 7, a latching insert 44 is provided, which has on a side facing the clamping screw 35 side a series of prismatic receptacles 45, 46, 47, 48, 49, 50. These are not exactly identical but are designed so that they define different transverse positions with respect to the needle bar 2 for the sewing machine needle 4 by a desired amount. Incidentally, the slider 44 is formed cylindrically so as to fit into the likewise approximately cylindrical bore of the inner space 17.

At the clamping screw 35 opposite side of the needle holder 7, this is provided with a window 51, which, as Figure 7 illustrates, a substantially straight edge 52 and on the opposite side has a toothed edge 53. The serrated edge 53 is formed by a series of approximately semi-circular cutouts in which a pin 54 extending away from the rear of the slider 44 lies. This can be pivoted out in the direction of the arrow according to FIG. 8 out of a corresponding interdental space, wherein the slider 44 rotates about its longitudinal axis. The pin 54 protruding out of the needle holder 7 can serve as a handle to move the slider 44 into desired axial positions. If a corresponding axial position is selected, a sewing needle 4 can be pushed through the opening 22 into the appropriately selected receptacle 45 to 50 and clamped to the slider 44 by means of the clamping screw 35.

FIG. 10 illustrates a further embodiment of the invention in which the needle holder 7 is adjustable on the needle bar 2 by means of a slider 55. This is in contact with a stepped side surface 56 of a recess of the slide 7, which is transversely adjustable on the needle bar 2 is stored. Each step of the side surface 56 is associated with a group of needles. The embodiment according to FIG. 10 shows 4 stages. If a finer adjustment or positioning of the needle 4 with respect to the needle bar 2 is desired, several stages can be provided. For clamping in displacement positions, which he occupies respectively, serve corresponding screws 57, 58, 64. The advantage of this embodiment lies in their slenderness and their low weight. If a stepless adjustment is to be made possible, the side surface 56 can be formed as a wedge surface. The manual setting is then a bit more demanding. For example, it can be made using landmarks.

FIG. 11 illustrates another embodiment of the invention, for which the previous description applies, with the exception of the features explained below.

In or on the needle holder 7, the bearing device 19 is provided which serves to receive the sewing needle. The bearing device 19 is adjustable by means of an electrically actuable actuator 63. This can be formed for example by an electric motor, a piezo drive or the like. By way of a gear mechanism, it effects the desired adjustment of the bearing device 19. For example, the gear may consist of a threaded spindle 58 and a spindle nut 59 driven by the same, which is connected to the bearing device 19. One or more position sensors may be provided to detect the rotational position of the actuator 63 or the linear position of the spindle nut 59. For a remotely controlled, preferably stepless adjustment of the position of the longitudinal axis of the sewing needle 4 with respect to the longitudinal axis of the needle bar 2 is possible.

The needle holder 7 according to the invention is provided in particular for industrial sewing machines, in which sewing machine needles with different needle thickness and preferably cylindrical piston or shaft are mounted and held adjustably in the transverse direction. Thus, a vote of the relative position between sewing needle 4 and the bottom of the groove 12 of the sewing needle 4 and the gripper 6 are made without having to adjust the gripper position and / or the needle protection position.

LIST OF REFERENCE NUMBERS

1

sewing machine

2

needle bar

3

table

4

sewing needle

5

foot

6

grab

6a

hook tip

7

needle holder

8th

arrow

9

Needle plate

10

opening

11

needle guard

12

fillet

13

eyelet

14

top

15

Needle trough, thread trough

16

screw

17

inner space

18

sliders

19

Storage facility

20

web

21

slot

22

Blind hole, opening

23

threaded hole

24

compression spring

25

investment funds

26

Rest wave

27

axis of rotation

28

thumbwheel

29

side surface

30

adjustment

31

Prism, investment funds

32, 33

contact surfaces

34

threaded hole

35

clamping screw

36

wave

37

feather

38

locking device

39

pen

40, 41, 42, 43

contact surfaces

44

pusher

45, 46, 47, 48, 49, 50

Recordings

51

window

52

edge

53

edge

54

spigot

55

pusher

56

side surface

57, 58, 64

screw

58

screw

59

spindle nut

60

slot

61

extension

62

catch hole

63

actuator

Claims (10)

Needle holder (7) for a sewing machine (1), in particular for an industrial sewing machine (1),
wherein the needle holder (7) is adapted to receive a sewing needle (4) to hold it in a holding position,
with an adjusting device (30) for adjusting the holding position of the needle holder (7) in a direction transverse to the sewing needle (4). Needle holder according to claim 1, characterized in that the adjusting device (30) for adjusting the relative position of the sewing needle (4) with respect to a needle guard (11) and / or a gripper (6) is arranged, which belongs to the sewing machine (1) and which serves to grasp the thread guided by the sewing needle (4). Needle holder according to claim 1, characterized in that the adjusting device (30) comprises a positionally adjustable abutment means (31) and a clamping device (35) to tension the sewing needle (4) against the abutment means (31). Needle holder according to claim 1, characterized in that it comprises a bearing means (19) which is adjustably held transversely to the sewing needle (4) and adapted to hold the sewing needle (4). Needle holder according to claim 1, characterized in that the adjusting device (30) is formed defining a plurality of needle holding positions in which the sewing needle (4) is held parallel to a needle movement direction (8) by the sewing movement of the sewing needle (4 ). Needle holder according to claim 1, characterized in that the adjusting device (30) is designed for manual adjustment. Needle holder according to claim 1, characterized in that the adjusting device (30) is set up for a stepwise position adjustment. Needle holder according to claim 1, characterized in that the adjusting device (30) is adapted to a stepless position adjustment. Needle holder according to claim 1, characterized in that the adjusting device (30) has an adjusting drive (28, 63). Needle holder according to claim 9, characterized in that the adjusting drive (63) is an electrically controllable and / or controllable drive.

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