JPH0557083A - Needlebar driving gear of sewing machine - Google Patents

Abstract

PURPOSE:To facilitate replacement of needlebars and to enable skipped stitch by providing a means for changing the dead center position of a neeldlebar, and providing a control means which stops the needlebar at a predetermined position regardless of changes in the dead center position. CONSTITUTION:During formation of normal seams an eccentric cam 44 is rotated and at its cam face the approach if a disk 174 to a solenoid 160 is detected by a photoelectric switch 182 and the disk 174 is attracted to the solenoid 160. Therefore a link 190 is pressed toward a link 72 and the link 72 is raised to a high position by the turning movement of a lever 62 and the amount of turning movement of levers 74, 83 is increased and the amplitude of a needlebar 114 is increased. In the case of the photoelectric switch 182 is turned off and the solenoid 160 is not excited and a roller 176 is pressed against the cam face by a spring 178 and the amplitude of the needlebar 114 is decreased and no seam is formed. While the roller 176 is most pressed against the cam face, the needle bar can be easily changed with the position of the top dead center of the needle bar being the same as during the normal sewing mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle bar driving device for a sewing machine, and more particularly to a needle bar driving device capable of changing the dead center position of the needle bar.

[0002]

2. Description of the Related Art A sewing machine is provided with a needle bar driving device. The needle bar driving device vibrates the needle bar holding the sewing needle in the axial direction in the axial direction, so that the sewing needle having the needle thread inserted through it penetrates the workpiece, and the thread loop of the needle thread and the bobbin thread are separated. The seams are formed by being entangled.

When performing pattern stitches and basting stitches with a sewing machine, so-called jump stitching is performed in which the number of stitches formed with respect to the feed amount of the work material is reduced as compared with normal sewing to form large stitches. For example, Japanese Patent Publication No. 57-35
Japanese Patent No. 675 discloses a needle bar drive device capable of jump stitching. In this needle bar drive device, the needle bar is vibrated in the axial direction by the needle bar crank rod through the engaging member and the engaging pin that is engageable with and disengageable from the engaging member. By connecting to, it is possible to perform jump stitching. That is, at the time of normal sewing, the engagement pin and the engagement member are engaged with each other, and the vibration of the crank rod is transmitted to the needle bar through the guide bar, so that the needle bar is vibrated and the stitch is formed. On the other hand, at the time of jump stitching, the engagement between the engaging pin and the engaging member is released, and the connection between the needle bar and the crank rod is broken, so that the needle bar is stopped at one point and The eyes are not formed.

However, when jump stitching is performed by stopping the vibration of the needle bar as described above, when the material to be processed is fed by the cloth feeding device, the needle of the sewing needle in which the upper thread is in a stopped state. Since it slides in the hole, there has been a disadvantage that the work material is pulled by the frictional force between the upper thread and the inner peripheral surface of the needle hole, and pulling is likely to occur. In particular, when the cloth feed amount is large or when the needle bar is stopped at a position far away from the cloth to be processed, this tendency becomes remarkable. If the bottom dead center of the needle bar during jump stitching, that is, the position of the point where the needle bar is closest to the work piece, is changed to a position where the sewing needle does not penetrate the work piece or does not form a stitch even if it penetrates. It is possible to perform jump stitching without stopping the needle bar, but conventionally, the position of the bottom dead center of the needle bar has not been changed in this way.

Since it is impossible to change the dead center position of the needle bar, the following inconvenience has occurred in addition to the execution of the jump stitch. First, when a boring knife is attached to the tip of the needle bar instead of the sewing needle, and when boring processing is performed on the work material, the cutting is performed according to the material and thickness of the work material by changing the bottom dead center position of the needle bar. It would be nice to be able to change the depth, but that was not possible. In addition, it has been practiced to perform a marking process such as a hand embroidery pattern by penetrating a work material without inserting a needle thread into a sewing needle.
If the bottom dead center position cannot be changed, the needle will be pierced deeply and the through hole will be too large, and a large amount of frictional heat will be generated in work materials with high resistance such as suede, backskin, and synthetic leather. Therefore, there is an inconvenience that the marking processing speed must be reduced. further,
There is also a problem that the amplitude of the needle bar must be increased more than necessary when performing normal sewing. If it is only for forming a stitch, it is not necessary to separate the sewing needle from the work material so much and the top dead center of the needle bar can be made relatively low. When setting, the needle bar needs to be raised in the top dead center because it interferes with the workpiece if the needle is not high enough. Therefore, the amplitude of the needle bar becomes unnecessarily large, the operating noise of the sewing machine becomes large, or the operating speed cannot be increased sufficiently.

In order to solve this inconvenience, the applicant of the present invention has made a needle bar drive device equipped with a dead center position changing means capable of changing at least one of the top dead center and the bottom dead center of the needle bar to an appropriate position. Was developed. When this device is applied to jump stitching, the position of the bottom dead center of the needle bar is changed so that it stops at the position where the sewing needle does not penetrate the work material or does not form a stitch when it penetrates. It Therefore, even if the needle bar is vibrated in the axial direction, no stitch is formed and it is possible to continue the vibration of the needle bar even during jump stitching, and it is possible to machine based on the frictional force between the needle thread and the inner peripheral surface of the needle hole. The timber of the material is prevented. Also,
Even when applied to perform boring processing or marking processing, the dead center position changing means changes the position of the top dead center or the bottom dead center of the needle bar according to the material and thickness of the work material. As a result, the work can be performed well.

[0007]

In the above needle bar drive device, it is desirable that the stop position of the needle bar does not change even if the dead center position of the needle bar changes. For example, in a multi-needle sewing machine that has a plurality of needle bars and only the selected needle bar is vibrated, the needle bars stop when the normal dead center position is set and when the dead center position is changed. When the positions are different, as will be described in detail later based on the embodiment, the operation of changing the selection of the needle bar becomes troublesome, and the device cost increases,
Alternatively, there arises a problem that work efficiency decreases. Also, when passing the needle thread through the needle hole of the sewing needle or setting the work material on the sewing machine, if the stop position of the needle bar is different during normal sewing and when the dead center position is changed, the position of the sewing needle will also change. There is a problem that it is inconvenient because it is not determined as one point.

The present invention has been made to obtain a needle bar drive device capable of solving these problems.

[0009]

The gist of the first invention is a dead center position changing means for changing the position of at least one of the top dead center and the bottom dead center of a needle bar that holds a sewing needle at the tip thereof. The needle bar drive device is provided with stop control means for stopping the needle bar at a predetermined substantially constant position regardless of the dead point position change of the needle bar.

The gist of the second invention resides in that the stop position of the needle bar is substantially the top dead center of the needle bar.

The gist of the third invention is that the stop position of the needle bar is the position of the needle bar when the balance reaches the top dead center.

[0012]

In the needle bar drive device constructed as described above, the stop control means causes the needle bar to stop at a predetermined substantially constant position both during normal sewing and when changing the dead center position. Be done.

Further, in the needle bar drive device according to the second invention, when the bottom dead center position of the needle bar is changed, the needle bar is stopped at about the top dead center, and the top dead center is usually It remains unchanged both when sewing and when changing the dead center position.

Further, in the needle bar drive device according to the third aspect of the present invention, the needle bar is stopped at a position at which the needle bar almost reaches the top dead center regardless of the change of the dead center position of the needle bar.

[0015]

According to the first aspect of the invention, the needle bar can be stopped at a substantially constant position both during normal sewing and when changing the dead center position. In this case, the needle bar selection can be easily changed, as will be described in detail with reference to later examples. Therefore, the cost of the apparatus becomes low, or the work of changing the needle bar selection can be easily performed, and the work efficiency is improved. Further, when the needle thread is inserted into the needle hole of the sewing needle, the needle is always stopped at a desired position.Therefore, especially in the case of a multi-needle sewing machine, the needle thread inserting device or the operator always puts the needle thread at a fixed position. It is sufficient to pass it through, and the effect of improving work efficiency can be obtained.

In the second invention, the bottom dead center position of the needle bar is changed and the amplitude of the needle bar is changed.
The needle bar selection can be changed and the upper thread can be inserted at a substantially constant top dead center position, so that the effect of reducing the device cost and improving the work efficiency becomes particularly large.

In the third aspect of the invention, the needle bar is stopped at the position at which the balance reaches almost the top dead center. However, normally, even if the dead center position of the needle bar is changed, the balance is almost above the top dead center. The position of the needle bar at the time when the dead point is reached does not change much between normal sewing and changing the dead point position. Therefore,
Even when the dead center position of the needle bar is changed and the amplitude of the needle bar is changed, it is possible to easily change the needle bar selection and insert the needle thread.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to jump stitching will be described in detail below with reference to the drawings. In FIG.
10 is a machine frame. The machine casing 10 includes a column portion 12, an arm portion 14 and a bed portion 16. Arm part 14
The bed portion 16 and the bed portion 16 extend horizontally from the column portion 12, respectively.
The wall 4 and the bed 16 are separated from each other by a partition wall 18. A sewing machine motor 22 is arranged in the column portion 12, and a pulley 26 is attached to an output shaft 24 of the sewing machine motor 22.
Are mounted so that they cannot rotate relative to each other. Also, the partition wall 1
A boss 28 is formed at 8 and the base end of the gear shaft 30 is rotatably supported via bearings 32 and 34. The gear shaft 30 extends in parallel with the output shaft 24, and a pulley 36 is attached to the tip end of the gear shaft 30 so as to be relatively non-rotatable. A belt 38 is wound around the pulley 26 and the pulley 36, and the rotation of the sewing machine motor 22 is transmitted to the gear shaft 30.

A gear 42 and an eccentric cam 4 are attached to the gear shaft 30.
4 is attached so as not to rotate relatively. Another boss 46 is formed below the boss 28 of the partition wall 18, and a gear shaft 48 is rotatably supported via bearings 50 and 52. At the tip of the gear shaft 48, the gear 4
A gear 54 having the same diameter as that of the gear 2 is attached so as not to rotate relative to the gear 54 and meshes with the gear 42.

One end of a link 60 is connected to one end face of the gear 54 via a spacer 58, and the other end of the link 60 is connected to one arm of a lever 62. Figure 1
As shown in, the lever 62 has a bell crank shape, and is rotatably supported by the partition wall 18 by a support shaft 64. Therefore, the rotation of the gear 54 causes the lever 62 to rotate around the support shaft 64 via the link 60. The other arm of the lever 62 is a rod-shaped slide shaft 66, and a cylindrical slider 68 is slidably fitted therein. The slider 68 is formed with an ear piece-shaped connecting portion 70, and one ends of a pair of links 72 are rotatably connected to each other with the connecting portion 70 interposed therebetween. The other ends of these links 72 are connected to the free ends of levers 74.

The base end of the lever 74 is fitted on the needle shaft 80 and is fixed by a spring pin 78. The needle bar shaft 80 is rotatably supported by a boss 82 formed on the partition wall 18, holds the lever 74 in the column portion 12, and at two positions in the arm portion 14 that are axially separated from each other. It holds two levers 84 (only one of which is indicated by a broken line in FIG. 1). Each lever 84 has a needle bar shaft 8
It extends in the direction opposite to the lever 74 with respect to the shaft center of 0, and as shown in FIG. 5, it is fixed to the needle bar shaft 80 by a spring pin 86 like the lever 74. Therefore, the rotational movement of the lever 62 around the support shaft 64 is transmitted to the lever 74 via the slider 68 and the pair of links 72, and the rotational movement of the lever 74 is transmitted to the lever 84 via the needle bar shaft 80. To be done.

As shown in FIGS. 4 and 5, the arm portion 1
4 has openings 9 at positions facing the respective levers 84.
0 (only one is shown in both figures) is formed, and a pair of guide rails 9 is provided above and below each opening 90.
2, 94 are provided along the longitudinal direction of the arm portion 14. The arm portion 14 holds the first head 96 and the second head 98 in a state of closing the openings 90. Each of the heads 96 and 98 is provided with a box-shaped needle bar case 100 that opens toward the machine frame 10. Horizontal engaging protrusions 106 and 108 are formed at the opening-side end portions of the upper and lower end plates 102 and 104 of the needle bar case 100, and are slidably fitted in the grooves of the guide rails 92 and 94, respectively. Has been done.

In the needle bar case 100 of the first head 96,
Two needle bars 114 and 116 are held so that they can vibrate vertically. The needle bars 114 and 116 hold sewing needles 118 and 120 at their lower ends, respectively. Needle bar 114,116
Are inserted into a cylindrical guide 122 extending from the upper end plate 102 into the needle bar case 100 and through holes 124 formed in the lower end plate 104, respectively.
Engaging members 126 and 128 are fitted in the central portion of 16 respectively, and are fixed by set screws 130. A spring 132 is provided between each of the engaging members 126 and 128 and the lower end plate 104, and the needle bar 11
4,116 is urged upward. Needle bar 114,116
Of the engaging members 126, 12
The upper end surface of the needle bar 8 is defined by abutting against the lower surface of the guide 122, and when the sewing operation is not performed, the needle bar 11
4,116 is made to stand by at the top dead center of the same position. The axial positions of the needle bars 114 and 116 with respect to the needle bar case 100 are obtained by loosening the set screw 130 and engaging members 126, 116.
It can be adjusted by changing the axial position of 128.

As shown in an enlarged view in FIG. 5, L-shaped engaging portions 134 and 136 each having a convex portion and a concave portion are formed at the rear end portions of the engaging members 126 and 128, respectively. .. On the other hand, the free ends of the two levers 84 connected to the needle bar shaft 80 are respectively connected via links 138 to the transmitter 1.
40 is rotatably connected. At the tip of each transmitter 140, the engaging portions 134, 1 of the engaging members 126, 128 are attached.
An engaging portion having a concave portion and a convex portion corresponding to 36 is formed. If the transmission member 140 has engaging members 126, 12
If it does not engage with any of 8
It rotates until it comes to a state of hanging from 8, but it is always engaged with either one of the engaging members 126 and 128,
Rotation is prevented. For example, as shown in FIG. 5, when the engaging portion 134 of the engaging member 126 is engaged, the concave portion and the convex portion are engaged with the convex portion and the concave portion of the engaging portion 134 to maintain a horizontal posture. is there. Therefore, when the transmitter 140 is lowered via the link 138 by the clockwise rotation of the lever 84, the needle bar 114 is pushed down against the biasing force of the spring 132 via the engaging member 126. When the lever 84 is rotated counterclockwise, the needle bar 114 is raised to the top dead center by the urging force of the spring 132 while the engaging member 126 and the transmitter 140 are engaged.

In this embodiment, the pivotal movement of the lever 84 causes the link 138, the transmitter 140 and the engaging member 12 to move.
6, 128 are converted into vertical vibrations of the needle bars 114, 116, and by changing the amount of clockwise rotation of the lever 84, the needle bars 114, 116
The bottom dead center of 116 has been changed.

The second head 98 also has a structure similar to that of the first head 96, and needle bars 146 and 148 holding sewing needles 142 and 144 at the lower end thereof are provided so as to be vertically vibrable. Needle bar 11 is also at the top dead center of needle bars 146 and 148.
The height is the same as the top dead center of 4,116, and the needle bars 146, 148 are held at the top dead center when the sewing machine is stopped.
Further, the needle bars 146 and 148 are provided with engaging members 126 and 128.
The engaging members similar to the above are attached respectively, and the link 13 is attached to the other lever 84 provided with the needle bar shaft 80.
The transmitter 140 connected via 8 is engaged with the engaging members. Therefore, the rotational movement of the lever 84 is converted into vertical vibration of the needle bars 146 and 148 by the link 138, the transmitter 140 and the engaging member. The pair of levers 84 is provided on the needle bar shaft 80.
Since both of them are rotated together with the lever 74, both levers 84 are simultaneously rotated by the rotation of the lever 74, so that the transmission element 14 is moved in each of the heads 96, 98.
The needle bars 114 and 146 or the needle bars 116 and 148 engaged with 0 are vibrated simultaneously and with the same amplitude.

As shown in FIG. 4, the arm portion 14 is provided with a needle exchange shaft 152 extending in parallel with the needle bar shaft 80. The needle exchanging shaft 152 extends through both side plates of the first and second heads 96 and 98, and the heads 96 and 98 integrally move along the guide rails 92 and 94 along with the axial movement thereof. Can be moved. The proximal end portion of the needle exchange shaft 152 is an elliptical ring portion 154, which is slidably fitted to a crank shaft 158 attached to the output shaft of a motor 156 fixed to the arm portion 14. Therefore, 2
When the two transmission elements 140 are engaged with the needle bar 114 and the needle bar 146 and all of the needle bars 114, 116, 146, 148 are stopped, the motor 156 is driven and the crank shaft 158 is rotated by half. For example, the needle exchange shaft 152 moves to the left in the figure, and the heads 96 and 98 are slid to the left accordingly. Thereby, the needle bar 114,
The engagement between each engaging member of 146 and each transmission element 140 is released at the same time, and each transmission element 140 continues to the needle bar 11.
6 and 148 are engaged with each other at the same time. Therefore, if the lever 84 is rotated next time, the needle bar 11
4,146 was made to stand by at the top dead center, and instead, the needle bar 11
6, 148 are moved up and down.

As shown in FIG. 1, a solenoid 160, which is an electromagnet device, is arranged in the column portion 12 between the eccentric cam 44 and the pair of links 72. The solenoid 160 includes a yoke 161, a coil 162, and a core 1.
The yoke 161 and the core 164 are excited by supplying an exciting current to the coil 162. The solenoid 160 is the partition wall 18
It is attached to the support member 166, which is fixed to, by bolts 168. The core 164 has a through hole 170 in the axial direction.
Is formed, and the rod 172 is slidably fitted therein. A disk 174 is concentrically fixed to one end of the rod 172, and a roller 176 is attached to the tip thereof. The disc 174 is made of a magnetic material and functions as a member to be attracted.

A spring 178 is provided between the step formed on the outer peripheral surface of the yoke 161 and the shoulder surface of the disc 174, and the disc 174 is biased in a direction away from the solenoid 160. The roller 176 is brought into contact with the cam surface of the eccentric cam 44. Therefore, due to the rotation of the eccentric cam 44, the rod 172 slides in the through hole 170 in the axial direction, and the disc 174 approaches and separates from the solenoid 160. The cam surface of the eccentric cam 44 is formed so that its approach speed decreases as the disk 174 approaches the solenoid 160, and as shown in FIG.
When the disc 174 is closest to the solenoid 160, there is almost no gap between the disc 174 and the end face of the solenoid 160. The rod 17
The second ring 170 is prevented from coming off from the through hole 170.

As shown in FIG. 1, a reflection type photoelectric switch 182 is provided on the machine casing 10 and is connected to a control device 184. On the other hand, a reflection surface 186 is formed on the surface of the gear 42 facing the photoelectric switch 182. Reflective surface 1
86 is formed at a position that reflects the detection light from the photoelectric switch 182 as shown in FIG. 2 when the disc 174 is brought closest to the solenoid 160 by the eccentric cam 44. Therefore, if the photoelectric switch 182 detects the reflecting surface 186 while the jump stitch is selected by the operator, a detection signal is output from the photoelectric switch 182 to the control device 184, and the control device 1 is based on the output signal.
An exciting current is supplied from 84 to the solenoid 160. Thus, the disc 174 is the solenoid 1
When the disc 174 is closest to the solenoid 160, the solenoid 160 is excited when the disc 174 comes closest to the solenoid 160.
As is clear from the graph, the attraction force of the solenoid 160, that is, the exciting current is small compared with the case where the disc 174 is attracted while the disc 174 is separated from the solenoid 160. Also, the solenoid 1 of the disc 174
The sound of collision with 60 is also reduced.

In this embodiment, the eccentric cam 44 constitutes a speed reducing means, and the photoelectric switch 182 and the reflecting surface 18 are provided.
6 and the control device 184 constitute the electromagnet device control means.

On the other hand, the other end of the rod 172 has the support member 16
Six through holes 188 are provided to extend and are connected to the intermediate portions of the pair of links 72 via links 190. By the axial movement of the rod 172 based on the rotation of the eccentric cam 44, the link 72 is moved via the link 190, and the slider 68 moves the slide shaft 6 of the lever 62.
6 can be moved.

When the operator finishes the sewing operation by operating the sewing end switch or the like,
A stop command signal is output from the control device 184 to the drive device of the sewing machine motor 22 based on the detection signal of the reflection surface 186 from the photoelectric switch 182. Therefore, the photoelectric switch 1 can be used both during jump stitching and during normal sewing.
When 82 detects the reflecting surface 186, that is, when the needle bars 114, 116, 146, 148 reach the top dead center as shown in FIG. 2, the sewing machine motor 22 is stopped and the needle bar 114 or the like is moved upward. Stop at dead point.

In the needle bar drive device constructed as described above, the gears 42 and 54 and the eccentric cam 44 are rotated by the activation of the sewing machine motor 22 during normal stitch formation. As shown in FIG. 2, if the photoelectric switch 182 detects that the disc 174 is closest to the solenoid 160 due to the cam surface of the eccentric cam 44, the solenoid 1
An exciting current is supplied to 60, and the disk 174 is attracted and held by the end surface of the solenoid 160.

When the disc 174 is suction-held by the solenoid 160, the rod 172 and the link 190 are pushed out to the link 72 side, so that the slider 68 moves to the tip side of the slide shaft 66 as shown in FIG. Then, the rotation of the lever 62 raises the link 72 to a higher position, the amount of rotation of the lever 74 and the lever 84 increases, and the amplitude of the needle bars 114 and 146 increases. Therefore, as indicated by the solid line in the graph of FIG. 7, the needle bars 114, 1
The position of the bottom dead center of 46 is a height at which the sewing needles 118 and 142 can sufficiently penetrate the work cloth, and the vertical movement of the needle bars 114 and 146 allows the work cloth held on the bed portion 14 to be sewn. Done.

On the other hand, when jump stitching is performed, the photoelectric switch 182 is turned off and the solenoid 1
The excitation of 60 is prevented. Therefore, as shown in FIG. 1, the disc 1 is urged by the urging force of the spring 178.
74 is separated from the solenoid 160, and the roller 176
Is kept pressed against the cam surface of the eccentric cam 44. Therefore, as the eccentric cam 44 rotates, the rod 1
72 and the link 190 are reciprocally moved in the axial direction.

When the roller 176 is most pushed out by the cam surface of the eccentric cam 44, the axial position of the rod 172 and the link 190 is the same as the state where the disc 174 is suction-held by the solenoid 160, so that the lever 84 moves. The amount of rotation in the counterclockwise direction becomes equal to the amount of rotation of the solenoid 160 in the excited state. Therefore, the needle bars 114, 14
The position of the top dead center of 6 is the same height during normal sewing and during jump stitching.

On the other hand, as the eccentric cam 44 rotates,
Since the rod 172 and the link 190 are moved to the eccentric cam 44 side by the urging force of the spring 178, the link 7
2 is pulled toward the eccentric cam 44 side. As a result, the slider 68 is moved to the base end side of the slide shaft 66 as shown in FIG. 1, and the amount of rise of the link 72 becomes smaller than that during normal sewing. Therefore, the amount of clockwise rotation of the lever 74 and the lever 84 becomes smaller, and the amplitude of the needle bars 114 and 146 becomes smaller than that during normal sewing. Therefore, FIG.
As indicated by the broken line in the graph of FIG. 3, the position of the bottom dead center of the needle bars 114, 146 is a height at which the sewing needles 118, 142 do not reach the upper surface of the workpiece, and the needle bars 114, 146 move up and down to be machined. No through holes are formed in the cloth and no seams are formed.

In this embodiment, the eccentric cam 44, the lever 62, the slider 68, the link 72, the solenoid 160,
The rod 172, the disc 174, the link 190 and the like constitute the dead center position changing means of the needle bars 114, 116, 146 and 148.

In this embodiment, the position of the top dead center is the same during jump stitching and during normal sewing. In either case, the needle bar in the stopped state is made to wait at the top dead center. The first and second heads 96,
By horizontally moving 98, the engaging members 126 and 128 that engage with the transmitter 140 can be changed to easily change the selection of the needle bar. Further, since the first and second heads 96 and 98 are moved by the common needle exchange shaft 152, it is possible to change the selection of needle bars of a plurality of heads all at once.

In the present embodiment, the photoelectric switch 18
2, the reflection surface 186 and the control device 184 constitute stop control means.

Further, in this embodiment, the electromagnet device is composed of a solenoid 160 having a yoke 161, a coil 162 and a core 164, and an exciting current is supplied to the coil 162 at the time of normal sewing, whereby the yoke is provided. Although 161 and the core 164 are excited to hold the disk 174 by suction, an electromagnet device including a permanent magnet may be used instead of the core 164. When this electromagnet device is used, the disc 174 is attracted and held by the magnetic force of the permanent magnet during normal sewing, and a current for canceling the magnetic force of the permanent magnet is supplied to the coil during jump stitching, whereby the disc 174 is electromagnetized. Away from. Therefore, it is not necessary to supply the exciting current at the time of normal sewing, and the current consumption can be small.

Next, a second embodiment of the present invention is shown in FIGS. The same members as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In this embodiment, instead of the solenoid 160, the solenoid 200
A support member 202 holding the is provided. As shown in the enlarged view of FIG. 9, the solenoid 200 has a head pin 204.
It is fixed to the support member 202 by. Solenoid 2
00 is a yoke 206, a coil 208 and a movable iron core 21.
The movable core 210 is pulled into the coil 208 against the biasing force of the spring 212 by supplying an exciting current to the coil 208.

A through hole 214 extending in the axial direction is formed in the supporting member 202, and a rod 216 is fitted therein so as to be movable in the axial direction. The retainer 21 is attached to the rod 216.
8 is fixed, and a roller 176 similar to that of the above-mentioned embodiment is attached to the tip portion. A spring 222 is arranged between the retainer 218 and the shoulder surface 220 of the support member 202, and the roller 176 is always brought into contact with the cam surface of the eccentric cam 44 by the urging force of the spring 222. The projecting portion of the rod 216 on the link 190 side from the supporting member 202 is a large diameter portion, and the shoulder surface of the large diameter portion is an engaging portion 224.

On the other hand, the support member 202 has an engaging portion 224.
A proximal end portion of an engaging claw 226 that can be engaged with is rotatably attached. The engaging claw 226 is connected to the projecting end of the movable iron core 210 by a pin and an elongated hole, and can be rotated around the shaft 228 as the movable iron core 210 slides.

During normal sewing, the solenoid 200 is demagnetized, and the urging force of the spring 212 causes the movable iron core 210 to project from the solenoid 200. Therefore, with the rotation of the eccentric cam 44, the engagement claw 226 engages with the rod 216 as shown by the chain double-dashed line in a state where the rod 216 is projected to the most link 72 side against the biasing force of the spring 222. Engaged with section 224, rod 216 and link 190 are held in a protruding state.

On the other hand, in the case of jump stitching, when the eccentric cam 44 reaches the position where the rod 216 is projected most toward the link 72 side, the solenoid 200 is excited and the movable iron core 210 is attracted to the inside of the solenoid 200. Be drawn into. Thereby, the engagement claw 226 is rotated to release the engagement with the engagement portion 224, the rod 216 is moved to the eccentric cam 44 side by the urging force of the spring 222, and the roller 176 is moved to the eccentric cam 44 side. It is brought into contact with the cam surface. Therefore, as the eccentric cam 44 rotates, the rod 2
16 and the link 190 are moved in the axial direction, the rotation amounts of the lever 74 and the lever 84 are reduced, and the bottom dead center positions of the needle bars 114 and 146 are increased, as in the above-described embodiment.

A third embodiment of the present invention is shown in FIG. In the figure, a sewing machine motor 304 is fixed to an arm portion 302 of a machine frame 300, and an output shaft 306 thereof has a gear 30.
8 is attached so as not to rotate relative to each other. Gears 310 and 312 are attached to the arm portion 302 and are meshed with each other, and the rotation of the gear 308 is transmitted to the gears 310 and 312. Gear 3
An eccentric shaft 314 is coupled to the rotary shaft 313 of the shaft 10. A rocker 316 is rotatably fitted to the eccentric shaft 314, and the rocker 316 is connected to one arm of a lever 318 rotatably supported by the arm portion 302 by a support shaft 317. There is. The other arm of the lever 318 is a slide shaft 320, and a slider 322 is slidably fitted therein. Therefore, the rotation of the gear 310 is converted into the swing of the rocker 316 by the eccentric shaft 314, and the rocking of the rocker 316 causes the lever 318 to rotate around the support shaft 317.

Guide holes 326 and 328 are formed in the vertical direction at the tip of the arm 302, and a needle bar 332 holding a sewing needle 330 at the lower end is attached so as to be vertically vibrable. A vertical movement link 336 is connected to the center of the needle bar 332 via a sleeve 334.
A needle bar lever 338 is connected to the vertical movement link 336. The needle bar lever 338 is rotatably supported by the needle bar shaft 340 held by the arm 302. The needle bar lever 338 and the slider 322 are connected to each other by a link 342 that extends substantially perpendicular to the slide shaft 320 and extends in the vertical direction.

The eccentric cam 3 is attached to the rotary shaft of the gear 312.
44 is attached so as not to rotate relative to each other, and the gear 312
It can be rotated together with it. A roller 346 held at one end of the rod 350 is in contact with the cam surface of the eccentric cam 344. The other end of the rod 350 is inserted into a through hole 354 formed in the vertical wall 352, and a cap 356 is attached to the small-diameter tip part thereof. Further, the retainer 3 is attached to the vertical wall 352.
58 is attached, and a spring 360 is arranged between the shoulder surface of the rod 350 and the retainer 358. Normally, the roller 346 is driven by the urging force of the spring 360.
Is brought into contact with the cam surface of the eccentric cam 344.

A mounting plate 362 is mounted on the vertical wall 352, and a solenoid 364 is fixed to the mounting plate 362. An engaging member 366 made of a magnetic material is arranged near the solenoid 364. The base end of the engaging member 366 is rotatably held by a mounting plate 362, and the solenoid 3 is held by a tension coil spring 368.
It is pulled toward the 64 side, but the tip part is the rod 350
Is engaged with the cap 356 attached to the solenoid 364, and is always moved toward and away from the solenoid 364 as the rod 350 moves due to the rotation of the eccentric cam 344. If the sensor (not shown) detects that the engaging member 366 is closest to the solenoid 364 and an exciting current is supplied to the solenoid 364 from a controller (not shown), the engaging member 366 is attracted and held by the solenoid 364. , The forward movement of the rod 350 due to the urging force of the spring 360 is blocked, and the roller 346 is moved to the eccentric cam 34.
4 is separated from the cam surface. The eccentric cam 344
The shape of is such that as the engaging member 366 approaches the solenoid 364, its approach speed decreases.

In this embodiment, the eccentric cam 344 constitutes the speed reducing means, and the sensor and the control device (not shown) constitute the control means for the solenoid 364.

From the middle of the link 342, the link 370
Extends substantially parallel to the needle bar lever 338, and connects the link 342 and the link 346. When a force in a direction orthogonal to the axial direction is applied to the link 342 via the link 370 by the rotation of the eccentric cam 344, the slider 322 slides on the slide shaft 320 according to the force. As a result, the oscillator 316 and the support shaft 3
17 and the distance A between the slider 322 and the support shaft 317.
And the ratio (lever ratio) is changed.

In the present embodiment, the shape of the cam surface of the eccentric cam 344 is such that the link 342 moves to the right in the figure as the lever 318 rotates clockwise, and the slider 322 moves to the base of the slide shaft 320. It can be slid toward the end. Therefore, the lever ratio becomes smaller, and the needle bar lever 33 with respect to the amount of rotation of the lever 318.
The amount of rotation of 8 is reduced. In contrast, lever 31
As 8 rotates in the counterclockwise direction, the link 342 is pushed to the left, and the slider 322 slides toward the tip of the slide shaft 320. Therefore, the lever ratio increases and the lever ratio increases. The rotation amount of the needle bar lever 338 is larger than the rotation amount of 318.

Although not shown, the arm portion 302 is provided with a photoelectric switch similar to that shown in FIG. 1, and the gear 310 has a reflecting surface. The reflective surface is the gear 3
It is formed at a position facing the photoelectric switch when the lever 318 rotates clockwise to the rotation limit by the rotation of 10. The photoelectric switch is connected to a control device (not shown), and when the reflection surface is detected, the detection signal is output to the control device.

In the needle bar drive device configured as described above, when normal sewing is performed, the solenoid 36
4 is not excited, and the rollers 346, the rod 350, the link 370, etc. can slide along the cam surface of the eccentric cam 344. By driving the sewing machine motor 304, the oscillator 3
The slide shaft 320 of the lever 318 is rotated via 16 and this rotation passes through the link 342 and the needle bar lever 33.
8 and the needle bar lever 338 is rotated about the needle bar shaft 340 as a fulcrum, whereby the needle bar 332 is moved up and down via the vertical movement link 336 and the sleeve 334. As the lever 318 rotates clockwise, that is, as the needle bar 332 is raised, the lever ratio becomes smaller, and as the lever 318 rotates counterclockwise, that is, as the needle bar 332 is lowered, the lever ratio becomes smaller. Becomes larger, the downward amplitude of the needle bar 332 becomes larger. Therefore, the bottom dead center position of the needle bar 332 becomes a height at which the sewing needle 330 can penetrate the work cloth, and the stitches are formed by the vertical movement of the needle bar 332.

On the other hand, in the case of jump stitching, when the needle bar 332 reaches the top dead center, the solenoid 364 is excited and the engaging member 366 is held by suction. Rod 350
Is moved to the rightmost when the needle bar 332 reaches the top dead center, the engagement member 366 moves the solenoid 364 the most.
Be approached. At this time, since the solenoid 364 is excited, the exciting current of the engaging member 366 can be small, and the collision noise at the time of attraction is also small.

The engagement member 366 is suction-held by the solenoid 364, so that the roller 346 is kept in a state of being separated from the cam surface of the eccentric cam 344. In this state, the lever ratio of the lever 318 when the needle bar 332 is lowered is the same as when the needle bar 332 is raised, so that the amplitude of the needle bar 332 becomes smaller than usual, and the bottom dead center position of the needle bar 332. ,
The height is such that the sewing needle 330 does not penetrate the work cloth. Therefore, even if the needle bar 332 is moved up and down, no stitch is formed on the work cloth.

When sewing is stopped, a stop command signal is output to the drive circuit of the sewing machine motor 304 in response to the detection signal of the reflective surface being input from the photoelectric switch to the control device. Therefore, the needle bar 332 is stopped in the clockwise rotation limit of the lever 318, that is, in the state where the needle bar 332 is located at the top dead center. Since the top dead center position of the needle bar 332 is the same height during both jump stitching and normal sewing, the needle bar 332 always stops at the same height.

A fourth embodiment of the present invention is shown in FIG. In this embodiment, a pulley 404 is rotatably supported on the arm portion 402 of the machine casing 400. A belt 406 is wound around the pulley 404 so that the rotation of a sewing machine motor (not shown) is transmitted. The eccentric shaft 4 is attached to the rotary shaft 408 that is rotatable integrally with the pulley 404.
10 is coupled, and an oscillating body 412 is rotatably fitted to the eccentric shaft 410. The free end of the rocker 412 is connected to the free end of the lever 414.

The base end portion of the lever 414 is fixed to the support shaft 420 of the toothed pulley 418 rotatably supported by the arm portion 402 so that the lever 414 and the toothed pulley 418 rotate integrally. Has been done. Also, the arm portion 402
A toothed pulley 422 is rotatably supported by the toothed pulley 422, and a toothed belt 424 is wound between the toothed pulleys 418 and 422. Therefore, the vertical movement of the rocker 412 based on the rotation of the pulley 404 is converted into the rotational movement of the lever 414, and the rotational movement of the lever 414 is transferred to the toothed pulley 422 via the toothed pulley 418 and the toothed belt 424. It is being transmitted. A slide link 426 is integrally rotatably attached to the toothed pulley 422. The slide link 426 is provided with a notch 428 extending in the longitudinal direction (left and right direction in the drawing), and
0 is slidably fitted.

Two guide holes 431 are concentrically formed at the tip of the arm portion 402, and a needle bar 434 holding a sewing needle 432 at its lower end is vertically oscillatably inserted. .. The sleeve 43 is provided at the center of the needle bar 434.
The vertical movement link 438 is connected to the vertical movement link 438 via a needle bar lever 440. The needle bar lever 440 is rotatably supported by the needle bar shaft 442 attached to the arm portion 402. The needle bar lever 440 and the slider 430 are connected by a link 444 that extends in a vertical direction and is substantially orthogonal to the slide link 426.

At the center of the link 444, a piston rod 452 slidable in the air cylinder 450 fixed to the arm 402 is provided via a slide link 426 and a link 446 extending substantially parallel to the needle bar lever 440. It is connected. The inside of the air cylinder 450 is divided into two chambers 454 and 456 by a piston 453, and each chamber 454 and 456 is connected to an air supply device 460 via an electromagnetic direction switching valve 458. Electromagnetic directional control valve 458
Includes a solenoid 462 and a spring 464. Normally, the solenoid 462 is demagnetized, and the chamber 456 is connected to the air supply device 460 and the chamber 454 is connected to the atmosphere by the urging force of the spring 464. 11, the piston rod 452 is moved forward (moved to the left in the figure), but if the solenoid 462 is excited by a control device (not shown), the chamber 454 becomes the air supply chamber 460 and the chamber 456 becomes the atmosphere. Therefore, the piston rod 452 is moved backward (moved to the right in the figure).

The arm portion 402 is provided with a photoelectric switch as in the first embodiment, and is connected to the control device. The photoelectric switch detects the reflection surface formed on the slide link 426 and outputs the detection signal to the control device. The reflection surface is formed at a position facing the photoelectric switch when the slide link 426 is rotated most clockwise.

In the needle bar drive device constructed as described above, the solenoid 46 is used when normal sewing is performed.
2 is demagnetized, a leftward force is applied to the link 444, and the slider 430 is moved to the tip side of the slide link 426. By driving the sewing machine motor in this state, the pulley 404 is rotated, and the slide link 426 is rotated integrally with the toothed pulley 422 via the oscillator 412, the lever 414, and the toothed pulley 418. .. This rotational movement is caused by the slider 430 and the link 444.
Is transmitted to the needle bar lever 440 via the
Is rotated about the needle bar shaft 442, the needle bar 434 is moved up and down. Since the slider 430 is located at the tip of the slide link 426, the amount of rotation of the needle bar lever 440 with respect to the amount of rotation of the slide link 426 increases, and the amplitude of the needle bar 434 increases. Therefore, the bottom dead center position of the needle bar 434 becomes a height at which the sewing needle 432 can sufficiently penetrate the work cloth, and the stitch is formed.

On the other hand, when jump stitching is performed, the solenoid 462 is energized, so that the slider 4
30 is moved to the base end side of the slide link 426. In this state, slide link 42 as in normal sewing
When 6 is rotated, the slide link 426
The amount of rotation of the needle bar lever 440 with respect to the amount of rotation of the needle bar 434 becomes small, the position of the needle bar 434 at the bottom dead center becomes high, and the position of the top dead center becomes low, so that the amplitude becomes smaller than that during normal sewing. Therefore, the bottom dead center position of the needle bar 434 becomes a height at which the sewing needle 432 does not penetrate the work cloth, and no stitch is formed even when the needle bar 434 is moved up and down.

When sewing is stopped, the solenoid 462 is demagnetized in response to the detection signal of the reflection surface being output from the photoelectric switch to the control device, the slider 430 is moved to the tip side of the slide link 426, and the sewing machine is sewn. A stop command signal is output to the motor, and the needle bar 434 is stopped at the top dead center. The needle bar 434 can be stopped at the same position during normal sewing and jump stitching.

In the present embodiment, when jump stitching is performed, the solenoid 462 is excited to move the piston rod 452 backward while the needle bar 434 is descending, and the piston rod 452 is demagnetized while the needle bar 434 is rising. It is also possible to move forward and to raise only the bottom dead center position without changing the top dead center position of the needle bar 434.

A fifth embodiment of the present invention is shown in FIG. In this embodiment, a sewing machine motor 504 is fixed to the column portion 502 of the machine casing 500. The sewing machine motor 504 is rotatable in both forward and reverse directions, and its output shaft 505
A pulley 506 is attached to this so as not to rotate relative to it. The needle bar shaft 50 is provided above the sewing machine motor 504.
8 is rotatably held by a boss formed on the partition wall 509. A pulley 510 is attached to the needle bar shaft 508 so that the pulley 510 cannot rotate relative to the needle bar shaft 508. A belt 512 is wound around the pulley 506 and the pulley 510 so that the rotation of the sewing machine motor 504 is transmitted to the needle bar shaft 508. It has become.

The needle bar shaft 508 is extended to the arm portion side (not shown) of the machine frame 500, and a lever 514 is attached to the arm portion by a spring pin 516 so as not to rotate relative to each other. A transmission element 520 is connected to a free end portion of the lever 514 via a link 518. Further, the arm portion is provided with a needle bar case similar to that of the first embodiment, and a needle bar 524 having a lower end holding a sewing needle 522 is vertically movably held in the needle bar case. The needle bar 524 is biased in the upward direction by a spring (not shown). An engagement member 526 is attached to the needle bar 524, and the transmission element 520 is engaged with the engagement member 526.

The sewing machine motor 504 has a rotation control device 53.
0 is connected. An encoder (not shown) is attached to the output shaft of the sewing machine motor 504, the rotation angle and the rotation direction of the sewing machine motor 504 are detected, the detection signal is input to the rotation control device 530, and the drive circuit of the motor 504 is based on the detection signal. A control signal is output to control the rotation of the motor 504.

Therefore, during normal sewing, the rotation control device 530 increases the rotation amount of the sewing machine motor 504, and the rotation amounts of the needle bar shaft 508 and the lever 514 are increased, thereby increasing the amplitude of the needle bar 524. A stitch is formed on the work cloth by the sewing needle 522. On the other hand, during jump stitching, the rotation amount of the sewing machine motor 504 is reduced, the amplitude of the needle bar 524 is reduced, and the bottom dead center position is changed to a height at which the sewing needle 522 does not penetrate the work cloth, and No formation takes place. The top dead center position does not change, and the needle bar 524 can be stopped at the same position during normal sewing and jump stitching.

In this embodiment, the encoder and rotation control device 530 also serve as stop control means.

In this embodiment, the rotation control device 530
By increasing the rotation angle of the sewing machine motor 504 at the end of sewing to raise the top dead center position of the needle bar 524, the rising end positions of the needle bar 524 and the sewing needle 522 can be made higher than those at the time of sewing. Therefore, it is possible to facilitate the work of setting the work cloth on the sewing machine while performing the sewing quietly with a relatively small amplitude. Further, the rotation angle of the sewing machine motor 504 in both the forward and reverse directions is changed by the same amount,
By raising or lowering the top dead center and the bottom dead center of the needle bar 524 by the same amount, it is possible to shift only the vibration center without changing the amplitude of the needle bar 524. By doing this, when performing a marking process on the work cloth, it is possible to raise only the vibration center of the needle bar 524 as compared with during normal sewing so that only the tip of the sewing needle 522 pierces the work cloth. When performing jump stitching, the needle bar 524
By further raising the vibration center of the sewing needle 522
Can be prevented from sticking to the work cloth.

Although some embodiments of the present invention have been described above, in these embodiments, a backup battery or the like is provided in preparation for a momentary power failure or the like to be cut off during excitation of the solenoid to cut off the current. It is desirable to provide. By providing the battery in this way, for example, it is possible to favorably prevent the eccentric cams 44 and 176 from colliding with each other and the vibration speed of the needle bar 114 or the like from suddenly changing in the first embodiment.

Further, in the first embodiment, when the solenoid 160 is in the demagnetized state, the jump stitching operation is always performed, so the solenoid 160 is
It is impossible to adjust the position where the sewing needles 118, 120 and the like meet the hook with the demagnetization of the solenoid.
If an eccentric cam is disposed in the vicinity of the position, and the eccentric cam is manually rotated to move the roller 176 and the rod 172 to set the sewing needle 118 and the like to the normal sewing position, the solenoid 160 can be provided. The above-described adjustment work can be performed while demagnetizing.

In addition, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view showing a needle bar descending state during jump stitching in a needle bar drive device according to a first embodiment of the present invention.

FIG. 2 is a front sectional view showing the needle bar raised state in the above apparatus.

FIG. 3 is a front cross-sectional view showing the needle bar lowered state during normal sewing in the above device.

FIG. 4 is a front view (partial cross section) showing a main part of a sewing machine including the above-described device.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a graph showing the relationship between the attraction force of the solenoid of the above apparatus and the distance to the attracted member.

FIG. 7 is a graph showing changes in the amplitude of the needle bar during normal sewing and jump stitching of the above device.

FIG. 8 is a front view showing a main part of a sewing machine equipped with a needle bar drive system that is a second embodiment of the present invention.

FIG. 9 is a front cross-sectional view showing a main part of the apparatus.

FIG. 10 is a front view (partial cross section) showing a main part of a sewing machine provided with a needle bar drive system according to a third embodiment of the invention.

FIG. 11 is a front view (partial cross section) showing a main part of a sewing machine including a needle bar drive system according to a fourth embodiment of the present invention.

FIG. 12 is a front sectional view showing a main part of a needle bar driving device according to a fifth embodiment of the present invention.

[Explanation of symbols]

 44 Eccentric cam 62 Lever 68 Slider 72 Link 74 Lever 80 Needle bar shaft 84 Lever 114 Needle bar 116 Needle bar 160 Solenoid 172 Rod 174 Disc 176 Roller 178 Spring 182 Photoelectric switch 184 Control device 186 Reflecting surface 190 Link 200 Solenoid 222 Spring 224 Engaging portion 226 Engaging claw 314 Eccentric shaft 318 Lever 322 Sliding element 332 Needle bar 344 Eccentric cam 346 Roller 350 Rod 360 Spring 364 Solenoid 366 Engaging member 368 Tensile coil spring 410 Eccentric axis 414 Lever 426 Slide link 430 Sliding element Needle bar 450 Air cylinder 452 Piston rod 458 Electromagnetic directional control valve 504 Sewing machine motor 524 Needle bar 530 Rotation control device

Claims (3)

[Claims] 1. A needle bar drive device comprising dead center position changing means for changing the position of at least one of the top dead center and the bottom dead center of a needle bar holding a sewing needle at its tip. A needle bar drive device for a sewing machine, comprising stop control means for stopping the needle bar at a predetermined substantially constant position regardless of the change of the dead center position. 2. The needle bar drive device according to claim 1, wherein the stop position of the needle bar is substantially the top dead center of the needle bar. 3. The needle bar drive device according to claim 1, wherein the stop position of the needle bar is the position of the needle bar at the time when the balance almost reaches the top dead center.