JP2000116973A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elimination backlash of a drive force transmission shaft in the shaft direction by equipping a stress giving means to give compressive stress or tensile stress to a drive force transmission shaft to transmit the drive force to a sewing machine head or a shuttle part and a drive force transmission shaft between thrust bearings. SOLUTION: Lateral movement of a sewing machine head 9 and a shuttle part 10 is driven by the drive force of a drive device 13 and generated drive force is transmitted to screw shafts (drive force transmission shafts) 14, 16. The screw shafts 14, 16 are rotatably hung on and supported respectively between thrust bearings 14a and between thrust bearings 16a equipped on both side frames 7c, 7d. A stress giving unit 32, i.e., a stress giving means to give compressive stress in the shaft direction, is attached on each one end part of screw shaft 14, 16. Compressive or tensile stress applied on the screw shafts 14, 16 by the stress giving unit 32 is made supported by the thrust bearings 14a, 16a, Thus, a stable support condition without backlash can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine mainly used for futon binding and the like.

[0002]

2. Description of the Related Art Sewing machines used for sewing large-sized objects such as curtains and futons are disclosed, for example, in Japanese Patent Publication No. Sho.
No. 1-18472 is known. In this type of sewing machine, the sewing machine head and a shuttle portion disposed immediately below the sewing machine head are horizontally moved while maintaining a paired state up and down, and are synchronously driven. The sewing object, which is substantially horizontally supported by the support table between the portions, is sewn efficiently. The horizontal movement of the sewing machine head and the shuttle unit is performed by moving the machine frame to which the sewing machine head and the shuttle unit are attached in a straight line and by a feed mechanism provided in the machine frame in a direction orthogonal to the moving direction of the machine frame. By the linear movement of the sewing machine head and the shuttle, it can be freely performed on the XY coordinate table.

[0003] As a feed mechanism of the sewing machine head and the shuttle,
There are (1) a device using a timing belt, and (2) a device using a screw shaft. The feed mechanism of (1) moves a sewing head attached to an arbitrary portion of the timing belt between the pulleys by rotating and driving an endless timing belt wound around a pair of pulleys. The feed mechanism of (2) converts a rotational driving force of the screw shaft into a horizontal moving force of the sewing head by a nut member on the sewing head screwed onto the screw shaft. A mechanism for transmitting a sewing driving force (a driving force for vertically moving the needle) to the sewing machine head and a mechanism for transmitting a driving force for synchronously driving the shuttle portion to the shuttle portion in synchronization with the sewing drive of the sewing head are also provided. There is provided a device using a timing belt and a device using a spline shaft.

[0004]

In the above-described sewing machine, the horizontal moving range of the sewing machine head and the shuttle by the feed mechanism is conventionally required in order to accommodate sewing of a larger workpiece. From 2-3m to larger (3m
Above). However, if the horizontal movement range of the sewing head or the shuttle is large, a mechanism for transmitting a driving force for horizontal movement to the sewing head or the shuttle,
As a mechanism for transmitting the sewing driving force, a mechanism using a timing belt is more suitable for a mechanism using a screw shaft or a spline shaft because problems such as loosening tend to occur. Even if the support span of the screw shaft and spline shaft is increased due to the increase in the horizontal movement range of the sewing machine head and the shuttle, bending due to its own weight can be easily eliminated by installing supports, etc. In general, the driving accuracy can be easily ensured, and therefore, it is easier to use than a timing belt.

In particular, since the sewing machine head and the shuttle portion need to be aligned with high accuracy (1/100 mm or less in error) so as to always form a pair, the feed of the sewing machine head and the shuttle portion is required. Accuracy is important. However, in the feed mechanism using the screw shaft, it is difficult to secure the supporting accuracy in the axial direction of the screw shaft whose both ends are supported by the bearings, and there is a case where slight rattling occurs. If a slight displacement occurs between the sewing machine head and the shuttle due to the rattling of the screw shaft in the axial direction, the quality of the sewing product is greatly affected. The rattling of the screw shaft in the axial direction is caused by dimensional tolerance of the screw shaft, dimensional change of the screw shaft due to linear expansion coefficient with respect to temperature change (change of length), and the like. There has been no means. For example,
If the axial dimension of the screw shaft changes due to temperature changes compared to when assembling, rattling may occur after temperature changes even if a stable support state is obtained without rattling at the beginning of installation. Therefore, adjustment work is required. But,
The adjustment work is not easy, and the work is troublesome. Also,
If a long screw shaft is used to extend the horizontal movement range of the sewing machine head and the shuttle, the change in the axial dimension of the screw shaft becomes more remarkable, which has been an obstacle to the expansion of the movement range.

In recent years, various types of multi-head sewing machines having a plurality of sewing heads have been developed. In this multi-head sewing machine, there is a type in which a plurality of sewing machine heads are horizontally moved by the same screw shaft, and a long screw shaft of 4 m or more is required. become. Similarly, with regard to the horizontal feed of the shuttle, when a plurality of shuttles are moved by the same screw shaft, the problem of the movement accuracy becomes remarkable. And these problems are caused by the increase in the number of
This has been an obstacle such as expansion of the horizontal movement range of each sewing head. In addition, the above-mentioned problem is not limited to the screw shaft for horizontal movement, but similarly occurs for the spline shaft for transmitting the sewing driving force.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and applies a compressive or tensile stress to various driving force transmission shafts supported between thrust bearings by a stress applying means. It is possible to stably support the machine by eliminating rattling, and as a result, it is possible to improve the operation accuracy of the sewing machine head and the shuttle, and to sew a larger workpiece with high accuracy. An object of the present invention is to provide a sewing machine.

[0008]

According to the first aspect of the present invention, a horizontally movable sewing machine head and a shuttle portion disposed immediately below the sewing machine head are horizontally moved while maintaining a paired state with each other. In a sewing machine for sewing a workpiece to be sewn disposed between the sewing head and the shuttle portion by synchronous driving, an axial end is supported by a thrust bearing, and the sewing head or the shuttle portion of the shuttle portion is supported. A compressive stress or a tensile stress is applied to the driving force transmitting shaft for transmitting driving force to the sewing machine head or the shuttle portion, and the driving force transmitting shaft between the thrust bearings, being provided in parallel with the movement locus and being driven to rotate. And a stress applying means for applying a force. In the invention according to claim 2, in the sewing machine according to claim 1, the stress applying means includes:
A unit comprising a fixing ring coaxially fixed to an end of the driving force transmission shaft, and a stress adjusting member provided with a variable amount of protrusion in the fixing ring axial direction on the fixing ring; By changing the amount of projection of the stress adjusting member in the axial direction of the fixed ring, a compressive stress or a tensile stress acting on the driving force transmission shaft between the thrust bearings is changed. .
According to a third aspect of the present invention, in the sewing machine according to the first or second aspect, the driving force transmission shaft is a screw shaft that transmits a driving force for horizontal movement to the sewing head, and the sewing head is a lifting mechanism. Is characterized by being able to move up and down freely.

According to the first to third aspects of the present invention, the compressive or tensile stress applied to the driving force transmission shaft by the stress applying means is supported by the thrust bearings at both axial ends of the driving force transmission shaft. To do. This allows
The driving force transmission shaft is constrained between the thrust bearings at both ends, and there is no fear of generating a gap or the like that causes axial displacement such as rattling, and a stable supporting state without rattling is realized. Various configurations can be adopted as the stress applying unit. In the stress applying unit of the second aspect, the stress is applied to the driving force transmission shaft by adjusting the screwing position of the screwing ring with respect to the fixing ring. The compression or tension stress can be easily adjusted. According to the invention described in claim 3,
Since the supporting state of the screw shaft is stable, the sewing machine head can be accurately moved horizontally. Further, even if the vibration generated when the lifting mechanism raises and lowers the sewing machine head acts on the screw shaft, no displacement occurs in the screw shaft, and the sewing machine head can always be moved horizontally with high precision.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) In FIGS. 1 to 3, a sewing machine 1
Is a substantially horizontal base 5 on which a support 4 for supporting a workpiece such as a futon is disposed substantially horizontally.
Are arranged over a pair of vertical members 2 provided on both sides of the vertical member 2 in parallel with each other. (The depth direction of the paper in FIG. 1, the horizontal direction in FIGS. 2 and 3)
A left and right direction (right and left in FIG. 1, depth direction in FIG. 2, and FIG. 3) along a rectangular frame-shaped machine frame 7 that travels and moves along an upper frame 7 a laid in an upper part of the machine frame 7. The sewing machine has a basic configuration including a sewing head 9 that is horizontally moved (up and down direction) and a shuttle 10 that is horizontally moved horizontally along a lower frame 7b that extends horizontally below the machine casing 7. . In the sewing machine 1, the sewing machine head 9 and the shuttle 10 are moved up and down and left and right while maintaining the paired state up and down by the front and rear drive of the machine frame 7 and the left and right movement of the sewing machine head 9 and the shuttle 10. By performing synchronous driving while freely moving horizontally, a relatively large sewn object such as a futon horizontally supported by the support table 4 is sewn between the both. Drive sources 8a and 8b, such as a turning servomotor, are connected to the sewing machine head 9 and the shuttle unit 10. The turning operations of the sewing machine head 9 and the shuttle unit 10 do not need to be synchronized.
In FIG. 1, reference numeral 3 denotes a horizontal member for connecting the two vertical members 2 to each other;
Denotes a slide shoe, and 12 denotes thrust bearings provided at four lower corners of the machine frame 7.

Both the left and right movements of the sewing machine head 9 and the shuttle unit 10 are performed by the driving force of a driving device 13 (see FIG. 1) including an electric motor mounted on the machine frame 7. That is, the driving force generated from the driving device 13 is
A belt 15 is attached to a screw shaft 14 supported between the side frames 7c and 7d on both sides along the upper frame 7a of the machine frame 7.
Via the lower frame 7b and further supported between the side frames 7c and 7d.
Is also transmitted via the belt 17 to rotate the screw shafts 14 and 16. The sewing machine head 9 is mounted on a head base 18 movably provided along a guide member 7e extending over substantially the entire length of the upper frame 7a.
The head base 18 is supported so as to be movable up and down through the head base 18.
Is horizontally moved by converting a rotational driving force of the screw shaft 14 into a driving force of horizontal movement by a nut member 20 (see FIG. 4) screwed to the screw shaft 14.
The sewing head 9 is freely moved horizontally. On the other hand, hook part 1
0, the hook base 10a movably provided along the guide member provided on the lower frame 7b is screwed to the screw shaft 16 with a nut member (not shown).
The horizontal movement is performed by the rotation drive of the screw shaft 16. FIG.
The stay 19 a is supported by a bracket 19 b on the head base 18 side so as to be able to move up and down. The stay 19 a is moved up and down integrally with the connecting plate 19 c at the tip of the elevating mechanism 19 and the sewing machine head 9 to move the sewing machine head 9 up and down. To make it smooth. FIG.
Reference numeral 7f denotes a cover that covers the outside of the side frames 7c and 7d.

The sewing head 9 and the shuttle portion 10 are provided with spline shafts 21 and 22 for transmitting sewing driving force, respectively. These spline shafts 21 and 22
Both are supported by bearings 21a, 22a between the side frames 7c, 7d, and the driving force of the same driving device 23 provided on the upper frame 7a of the machine frame 7 is:
By being transmitted via the belts 24 and 25, it is driven to rotate.

As shown in FIG. 5, the sewing head 9 includes
Pulley 2 provided so as to be able to rotate integrally with spline shaft 21
6, the pulley 26 and the pulley 9 on the sewing machine head 9 side
The rotational driving force of the spline shaft 21 is transmitted through a belt 27 wound between the needles 9a and 9a, and is converted into a vertical driving force of the needle 9b and the presser foot 9c in the sewing machine head 9. The sewing head 9 can be moved up and down by a lifting mechanism 19 which is a fluid pressure cylinder. At the time of sewing, the sewing machine head 9 is moved down to a target position to drive the needle 9b.
7 is given an appropriate tension, and the belt 27 bends at the time of lifting, so that the lifting is not hindered. As the pulleys 26 and 9a and the belt 27, it is more preferable to use toothed members in order to ensure the operation accuracy. Further, it is preferable to provide a tension roller or the like to maintain the tension of the belt 27 even when the sewing head 19 is raised. As shown in FIG.
The pulley 26 engaged with the driving device 13 functions as a sliding key slidable in the longitudinal direction of the spline shaft 21.
Even if the sewing head 9 is driven in the left-right direction by the driving force, the driving force can be transmitted from the spline shaft 21 to the belt 27 as in the case where the left-right movement of the sewing head 9 is stopped. On the other hand, the driving force is transmitted to the shuttle unit 10 from the spline shaft 22 via a pulley (not shown) slidably engaged with the spline shaft 22 in the longitudinal direction, a belt 29, a pulley 30, and a shaft 31. Done.

One end of each of the screw shafts 14 and 16 has a screw shaft 1
4 is provided with a stress applying unit 32 which is a stress applying means for applying an axial compressive stress. FIG. 6 is a cross-sectional view showing the stress applying unit 32 attached to the screw shaft 14. The stress applying unit 32 includes a fixing ring 33 coaxially fixed to an end of the screw shaft 14 and a screw coaxially screwed to the fixing ring 33.
Screw ring 34 fixed to rotate integrally with
It is comprised including. Both the fixing ring 33 and the screw ring 34 are formed by screws 33a and 34a.
The screw shaft 14 is fixed to a thinly cut support end 14b. The screw ring 34 is a screw portion 33 of the fixing ring 33.
b and one of thrust bearings 14a provided on the opposite side axially opposite to the screwed portion 34b and supporting both ends of the screw shaft 14 in the axial direction (FIG. In No. 6, a thrust bearing 14a) provided on one side frame 7d is provided with a contact end 34c which is abutted from inside the device 1. The thrust bearing 14a functions as a supporting body for supporting the pressing force applied from the screw ring 34. The end ring 36 is fixed to the screw shaft support end 14b protruding outside (the right side in FIG. 6) of the thrust bearing 14a.
A movement limit in the direction of the end opposite to the axial direction (left side in FIG. 6) is set. In FIG. 6, the thrust bearing 14a is
It is fixed from both sides by bearing retainers 28a, 28b. This is the same for the thrust bearing 14a on the side frame 7c side.

In FIG. 6, the screw shaft 1 of the end ring 36 is shown.
4 is fixed to the screw 3 from the cross-sectional diameter direction of the screw shaft 14.
The tightening of 6a is not limited to this, and various configurations such as, for example, a configuration in which a nut member is screwed into a screw portion formed at the tip of the screw shaft 14 can be adopted. However, since it is not easy to form a screw portion at the tip of the screw shaft 14 having a total length of several meters, in many cases, fixing by tightening the screw 36a is advantageous in terms of cost and the like. The fixing of the fixing ring 33 and the screw ring 34 to the screw shaft 14 is not limited to the tightening of the screws 33a and 34a from the cross-sectional radial direction of the screw shaft 14, and various configurations such as those using a chuck mechanism are employed. It is possible. However, since the structure of the chuck mechanism and the like is complicated and it is difficult to reduce the cost, fixing with the screws 33a and 34a is often advantageous in terms of cost and the like.

The screw 34 a is loosened, and a tool is applied to a tool hole or a tool engaging portion (not shown) formed around the screw ring 34, and the screw ring 34 is rotated and screwed to the fixing ring 33. The position is moved toward the tip of the screw shaft 14 (to the right in FIG. 6), and the screw ring 3
4, the thrust bearing 14a from the screw ring 34 (specifically, from the contact end 34c)
Is increased, and a displacement force in the direction of the side frame 7c on the opposite side acts on the screw shaft 14 as a reaction force. On the other hand, at the end of the screw shaft 14 on the side of the side frame 7c, the displacement force applied to the screw shaft 14 is supported by a supporting means (not shown). Stress is applied. as a result,
Thrust bearing 14a on both side frames 7c, 7d
The screw shaft 14 is in a restrained state between the thrust bearings 14a and the screw shaft 14, so that there is no room for forming a gap that causes a slight backlash,
A stable support state is obtained. The compressive stress applied to the screw shaft 14 can be easily changed depending on the screwing position of the screw ring 34 with respect to the fixing ring 33, and the screw ring 34 functions as a stress adjusting member. However, the compressive stress is such that the screw shaft 14 does not deform such as bending. When the screw ring 34 reaches the target screw position with respect to the fixing ring 33, it goes without saying that the screw 34a is retightened and fixed. In addition, the fixing ring 3
3 effectively abuts the axial end face 33c against the step portion 14c generated by the formation of the screw shaft support end portion 14b, so that the reaction force of the pressing force of the screw ring 34 against the thrust bearing 14a is effectively applied from the step portion 14c. It can be transmitted to the screw shaft 14. Screw shaft 1 that transmits driving force for horizontal movement to shuttle 10
6, the axial end portions are supported by the thrust bearing 16a, and the compressive stress is applied by the stress applying unit 32 similarly to the screw shaft 14, so that a stable supporting state without rattling is secured.

Therefore, according to the sewing machine 1,
The screw shafts 14 and 16 are stably supported without rattling, and even when driven to rotate, a state without rattling is maintained. As a result, there is no risk of displacement between the sewing machine head 9 and the shuttle unit 10. The screw shafts 14, 1
In the case where the axial dimension changes due to the linear expansion coefficient in 6, the screwing position of the screwing ring 34 with respect to the fixing ring 33 is changed so that the target compressive stress acts on the screw shafts 14 and 16. To In particular, in the case of the long screw shafts 14 and 16 having a length exceeding 3 m, a change in the axial dimension due to a temperature change as compared with the time of the initial assembly is relatively large. The compressive stress of 14 and 16 is eliminated, and conversely,
Due to the increase in the axial dimension when the temperature rises, the screw shaft 14,
Although there is a possibility that the compressive stress of the screw shaft 16 becomes extremely large, the compressive stress acting on the screw shafts 14 and 16 can be easily set within an appropriate range only by changing the screwing position of the screw ring 34 with respect to the fixing ring 33. Can be adjusted, screw shaft 14, 1
6 can be stably maintained in an ideal supporting state without play. As a result, a displacement between the sewing machine head 9 and the shuttle portion 10 that is greater than an allowable range can be reliably eliminated, and the quality of sewing products can be improved.

In the sewing machine 1, the lifting mechanism 1
Even if vibrations occur due to the driving of various operating parts such as 9, there is no risk of displacement of the screw shafts 14 and 16, so that the operating speed of the operating parts can be improved and the operating parts can be enlarged. become. In particular, vibration when the sewing machine head 9 moves up and down easily acts on the screw shaft 14. However, according to the sewing machine 1, even if the sewing machine head 9 is moved up and down, it gives an influence on the positioning accuracy of the sewing machine head 9 by the screw shaft 14. Since there is no influence, it is possible to improve the elevating speed of the sewing head 9. When frequently moving between different sewing positions in the horizontal direction, that is, so-called jump stitching, is required, the sewing head 9 may be used.
The sewing time can be reduced by improving the lifting speed of the sewing machine. Increasing the number of operating parts mounted on the sewing machine head 9, such as the upper thread trimming device 37 (see FIG. 5), leads to an increase in vibration at the time of lifting and lowering due to an increase in the weight of the sewing machine head 9.
Since the influence of the screw shafts 14 and 16 on the movement accuracy of the sewing machine head 9 and the shuttle unit 10 is almost eliminated, the number of mounting mechanisms on the sewing machine head 9 and the like and the degree of freedom of the configuration of these mounting mechanisms are improved. Multifunctionalization becomes free.

(Second Embodiment) Sewing machine 5 shown in FIG.
Numeral 0 is a multi-head type in which two sewing heads 9 are mounted on a machine frame 51. In this sewing machine 50, two sewing heads 9 are provided on the upper frame 51a of the same machine frame 51 in a left-right movement (horizontal movement; left and right in FIG. 7), and a shuttle 10 corresponding to each sewing head 9 is provided as described above. It is provided on the lower frame 51b of the machine frame 51 so as to be horizontally movable. The left and right dimensions of the machine frame 51 are about twice as large as the machine frame 7 of the sewing machine 1 shown in FIG.
Each is the same as that of the sewing machine 1 shown in FIG.
３3 m), and each pair of the sewing machine head 9 and the shuttle unit 10 moves left and right within a movable range secured on both left and right sides of the center of the machine frame 51 in the left and right direction. The support table 4 for supporting the workpiece between the sewing head 9 and the shuttle 10 is provided corresponding to the movable range of each pair of the sewing head 9 and the shuttle 10.

The side frames 51c, 5 on both sides of the machine frame 51
The sewing machine head 9 and the shuttle 10 are provided from the screw shafts 52 and 53 and the spline shafts 54 and 55 provided between
The mechanism for transmitting the driving force for horizontal movement and the sewing driving force is the same as that of the sewing machine 1 shown in FIG. Machine frame 51
Since the distance between the side frames 51c and 51d on both the left and right sides is as large as 5 to 6 m, the spline shafts 54 and 55
The support portions 56 projecting from the upper and lower frames 51a and 51b of the machine frame 51 support the central portion in the axial direction (longitudinal direction) to prevent bending, vibration during rotational driving, and the like (spline shaft 55). Are not shown).
In addition, the spline shafts 54 and 55 may be a single member having a length that can be installed and supported between the side frames 51c and 51d, but in FIG. 7, the two spline shafts 54a and 54b are connected to each other. The spline shafts 55a and 55b are connected to each other by a connecting portion 57 provided in the vicinity of the support portion 56 and fixed so as to be integrally rotatable.
Manufacturing a spline shaft by forming a spline groove in a long bar material of 5 to 6 m may cause a rise in cost because special large-sized processing equipment is required. The spline shafts 54 and 55 formed by connecting the shafts 54a and 54b to each other and the shafts 55a and 55b to each other
Since 4b, 55a, and 55b can be easily manufactured by ordinary processing equipment, the cost can be reduced. Further, as the spline shafts 54a, 54b, 55a, and 55b, a screw shaft applied to a single-head sewing machine can be diverted as it is, so that the cost can be further reduced.

The screw shafts 52 and 53 are rotatably supported between the thrust bearings 58a and 58b of the side frames 51c and 51d on both sides. Moreover, the screw shaft 5
The axial end portions 2 and 53 (the side frame 51d in FIG. 7)
Applying unit 3 attached to the end supported on the side)
2 is the thrust bearing 58b on the side frame 51d side
On the other hand, at the other axial end of the screw shaft 52, the reaction force of the pressing force from the stress applying unit 32 is supported by the thrust bearing 58a on the side frame 52c side. Is given a compressive stress, and a screw shaft 5 is provided between the thrust bearings 58a and 58b on both sides.
2, 53 are stably supported without rattling. Since the spline shafts 54 and 55 are rotated at a high speed of about 750 rpm, the rotations of the screw shafts 52 and 53 are sufficiently low and the deflection due to their own weight does not cause a problem. Although there is no means for supporting the middle, it is preferable to provide an intermediate support means,
Thereby, it is possible to cope with further lengthening.

Even in the multi-head sewing machine 50, the rattling of the screw shafts 52 and 53, particularly in the axial direction, can be prevented.
The movement accuracy of the sewing head 9 and the shuttle 10 can be improved,
The paired relationship can be reliably maintained. Moreover, even if the axial dimensions of the screw shafts 52 and 53 change due to temperature changes,
The stress applying unit 32 can maintain the screw shafts 52 and 53 in a stable support state, similarly to the sewing machine 1 in FIG.

In the above embodiment, the following changes are possible. (A) The stress applying means is applicable not only to the screw shaft for moving the sewing machine head 9 and the shuttle portion 10 left and right, but also to the spline shaft for transmitting the sewing driving force. Regardless of the driving force transmission shaft, rattling or the like can be prevented by applying the stress applying means, and operation accuracy can be improved by preventing vibration. (B) In the above embodiment, the sewing machine head 9 and the shuttle 10
Although the configuration in which a compressive stress is applied to the screw shaft for right and left movement has been illustrated, the present invention is not limited to this, and a configuration in which a tensile stress is applied to the screw shaft can also be adopted. In this case, for example,
The screw ring 34 of the stress applying unit 32 shown in FIG.
Is connected to the thrust bearing 14b in advance,
When the screw ring 34 is screwed into the fixing ring 33 to reduce the protrusion dimension t, a tensile stress can be applied to the screw shaft 14. Further, the mounting position of the stress applying unit 32 is
The screw shaft support end 14b is projected to the outside (right side in FIG. 6) of the device 1 through the thrust bearing 14a, and the reaction is applied to the fixing ring 33 fixed to the tip of the screw shaft support end 14b. In addition, a configuration in which the thrust bearing 14b is pressed from the outside by the screw ring 34 can be adopted. (C) In FIG. 6, the fixing object of the screwing ring 34 screwed to the fixing ring 33 is the screw shaft 14, but is not limited thereto, and may be the fixing ring 33 or the fixing ring 3.
It is also possible to use both 3 and the screw shaft 14.

[0024]

As described above, the sewing machine according to the present invention is provided with the stress applying means for applying the compressive stress or the tensile stress to the driving force transmission shaft supported between the thrust bearings. The rattling of the driving force transmission shaft in the axial direction can be eliminated, and high accuracy can be reliably obtained for the integral movement of the sewing machine head and the hook portion, contributing to the improvement of the quality of sewing products. Moreover, this makes it possible to increase the length of the driving force transmission shaft, so that the moving range of the sewing machine head and the shuttle section can be expanded to increase the size of the work to be sewn and the sewing machine head to be mounted on the sewing machine device. (Multiple heads) can be realized, and an excellent effect of contributing to an improvement in sewing efficiency can be obtained. According to the sewing machine of the second aspect, in the stress applying unit, the drive between the thrust bearings can be performed only by changing the amount of protrusion of the stress adjusting member from the fixing ring attached to the end of the driving force transmission shaft. Compressive stress or tensile stress acting on the force transmission shaft can be easily adjusted. Further, even if the driving force transmission shaft changes its axial dimension due to the linear expansion coefficient with respect to temperature change, the driving force transmission shaft can be adjusted by merely adjusting the amount of projection of the stress adjusting member in the fixing ring axial direction. An excellent effect is obtained such that the stress can be stably applied. In the sewing machine according to the third aspect, even if the vibration generated when the sewing machine head moves up and down acts, the influence on the movement accuracy of the sewing machine head and the shuttle by the screw shaft that is the driving force transmission shaft can be neglected. It has an excellent effect that it can be improved and the sewing time can be shortened.

[Brief description of the drawings]

FIG. 1 is a front view showing a sewing machine according to a first embodiment of the present invention.

FIG. 2 is a side view showing the sewing machine shown in FIG. 1;

FIG. 3 is a plan view showing the sewing machine of FIG. 1;

FIG. 4 is a front view showing the vicinity of a sewing head of the sewing machine shown in FIG. 1;

FIG. 5 is a side view showing a sewing head of the sewing machine shown in FIG. 1;

FIG. 6 is a front sectional view illustrating an example of a stress applying unit applied to the sewing machine of FIG. 1;

FIG. 7 is a front view showing a sewing machine according to a second embodiment of the present invention.

[Explanation of symbols]

1: sewing machine, 9: sewing head, 10: shuttle, 1
4, 16 ... driving force transmission shaft (screw shaft), 14a, 16a ...
Thrust bearing, 14b: drive force transmitting shaft end (support end), 32: unit (stress applying unit), 33 ...
Fixing ring, 34: stress adjusting member (screw ring), 50
... Sewing machine, 52, 53 ... Driving force transmission shaft (screw shaft),
58a, 58b ... thrust bearings.

Claims (3)

[Claims] 1. A horizontally movable sewing machine head and a shuttle portion disposed immediately below the sewing machine head are horizontally moved while maintaining a paired state with each other, and are synchronously driven. In a sewing machine for sewing an object to be sewn disposed between a shuttle portion and a shuttle portion, both ends in the axial direction are supported by thrust bearings, and are provided in parallel with a movement locus of the sewing machine head or the shuttle portion, and are rotationally driven. A driving force transmitting shaft for transmitting a driving force to the sewing machine head or the shuttle portion; and a stress applying means for applying a compressive stress or a tensile stress to the driving force transmitting shaft between the thrust bearings. Characteristic sewing machine. 2. A stress adjustment wherein the stress applying means is coaxially fixed to an end of the driving force transmitting shaft, and a stress adjusting means is provided on the fixing ring such that the amount of projection in the axial direction of the fixing ring is variable. A compressive stress or a tensile stress acting on the driving force transmission shaft between the thrust bearings by changing an amount of projection of the stress adjusting member in the axial direction of the fixed ring. 2. The sewing machine according to claim 1, wherein 3. The apparatus according to claim 2, wherein the driving force transmission shaft is a screw shaft for transmitting a driving force for horizontal movement to the sewing machine head, and the sewing machine head is vertically movable by a lifting mechanism. 3. The sewing machine according to 1 or 2.