JP3682360B2 - Sewing machine presser foot - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cloth presser device for a sewing machine.
[0002]
[Prior art]
Conventionally, the presser foot of the sewing machine has been provided with a mechanism for moving the presser foot up and down with a small stroke during sewing and retracting the presser foot further above the vertical movement range as required, such as thread trimming and frame movement. The device is known.
[0003]
For example, in the apparatus described in FIG. 21 of Japanese Patent Laid-Open No. 7-231991, a presser foot is attached to the tip of a drive arm that is swung by the rotation of an eccentric cam via a plurality of links, and is synchronized with the rotation of the main shaft. The work clamp is moved up and down. When retracting the presser foot, the retracting lever is rotated to rotate the drive arm in the direction away from the eccentric cam. Although not shown in the figure, it is described in text that a spring is provided to keep the cam follower portion of the drive arm in contact with the eccentric cam (column 9, column 1 See line 2).
[0004]
Further, in the apparatus described in Japanese Patent Laid-Open No. 6-238078, a cam follower is fitted to a drive cam provided with a cam groove on the outer periphery for causing the cloth presser to move up and down, and is synchronized with the main shaft during sewing. Then, the presser foot is moved up and down with a predetermined stroke by rotating the drive cam. Then, as a mechanism for retracting the presser foot upward, a retraction groove is provided in a part of the wall of the cam groove opposite to the cam surface, and the link is provided by letting the cam follower escape to the retraction groove as necessary. The presser foot is raised to the retracted position via In this device, a biasing force is applied to keep the cam follower in contact with the cam surface by the second compression coil spring.
[0005]
[Problems to be solved by the invention]
In these prior arts, when retracting the presser foot upward, it is necessary to move the cam follower against the urging force of the spring abutting the cam follower. These springs have a relatively large urging force in order to cause the cam follower to correctly perform an operation following the cam surface. For this reason, the conventional apparatus has a problem that a large load is applied to the presser foot retracting mechanism. In particular, since the number of heads is increasing in the embroidery sewing machine, the load applied to the presser foot retracting mechanism becomes a considerably large value in the entire multi-head sewing machine.
[0006]
Further, in the one described in Japanese Patent Application Laid-Open No. 6-238078, when the work clamp once retracted to the raised position is returned to the operating position, the main shaft is driven until the cam follower is returned from the retracting groove into the cam groove. Can not do it. Since the structure described in Japanese Patent Application Laid-Open No. 7-231991 also has a structure in which the cloth presser is retracted obliquely rearward and upward, after returning the presser foot to the operating position so that the through hole of the presser foot is located directly below the sewing needle. Otherwise, the spindle cannot be driven.
[0007]
For this reason, these conventional devices also have a problem that it takes time to resume the sewing operation from the state in which the presser foot is retracted.
Therefore, an object of the present invention is to solve such problems, to reduce the load when retracting the presser foot, and to shorten the time until the sewing operation is resumed.
[0008]
[Means for Solving the Problems]
The sewing machine presser device according to the present invention moves the presser foot up and down within a predetermined range at the sewing position and, if necessary, withdraws the presser foot to a retracted position further above the sewing position. In the apparatus, the presser foot drive cam fixed to the main shaft, the first swing member swinged within a predetermined range by the presser foot drive cam, the first swing member and the link are connected to each other, and A link mechanism that is connected to the presser foot by a link, and includes a second swinging member that moves the presser foot up and down by swinging itself upon receiving the swinging motion of the first swinging member. Furthermore, a cam follower provided at a joint in the link mechanism is engaged, and a guide cam provided with an arc-shaped cam groove for moving the cam follower provided at the joint along a predetermined arc-shaped locus is also provided. Prepare for that The inner cam is configured to be movable in a plane direction parallel to the arcuate trajectory so that the position of the arcuate cam groove can be changed, and the cam follower provided in the joint is provided in the arcuate cam groove of the guide cam. By moving the position of the guide cam in a state in which the second presser member is engaged, the second presser member is raised to the retracted position even during the swinging operation of the first control member. There is provided a guide cam moving means that can be put into a state of being moved or moved down in a predetermined range by lowering the cloth presser to a sewing position.
[0009]
According to the sewing machine presser device, at the time of executing the sewing, the first swinging member swings along a predetermined locus in response to the rotation of the main shaft. Then, the 2nd rocking | swiveling member connected via the link with respect to this 1st rocking | swiveling member rock | fluctuates, and the work clamp is moved up and down. At this time, any joint in the link mechanism moves along the arcuate cam groove of the guide cam, and the range of movement of the presser foot is defined by the movement range of the joint. On the other hand, when raising the presser foot to the retracted position, the guide cam moving means is driven to move the guide cam, and the joint engaged with the arcuate cam groove is moved in the direction of swinging up the second swing member. Let That is, the guide cam moving means moves the guide cam so that the position of the joint engaged with the arcuate cam groove swings up the second swing member. As a result, the presser foot is raised to the retracted position.
[0010]
According to the sewing machine cloth presser device, when the presser foot is raised to the retracted position, the engagement with the guide cam that restricts the movement of the link mechanism is not disconnected. Therefore, it is not necessary to apply a strong biasing force in order to ensure engagement with the guide cam at the time of sewing execution, and the load at the time of executing the retreat operation can be reduced.
[0011]
Further, the presser foot is only raised to the retracted position along the presser foot guide bar, and the engagement with the guide cam is maintained even when the presser foot is in the retracted position. Even if the main shaft is rotated while returning to the normal position, the presser foot only moves up and down along the presser foot guide bar via the link mechanism. Therefore, when the sewing is resumed from the retracted state, the rotation of the main spindle can be resumed before the presser foot returns to the sewing position, and the time required for the resumption can be shortened.
[0012]
Further, in the cloth presser device for a sewing machine according to the present invention, the second swing member further includes a first arm extending to the first swing member side and a second arm extending to the cloth presser side. A cam follower that includes two or more links between one arm and the first swing member and that is engaged with the arcuate cam groove is the first arm of the link connected to the first arm. The guide cam moving means is provided at an opposite joint, and when the position of the guide cam is changed so that the second swinging member is swung up, the arc-shaped cam groove is formed on the first arm. It is good to be comprised so that it may correspond to the locus | trajectory of the circular arc centering on the joint of a free end side.
[0013]
According to this configuration, even if the main shaft is continuously rotated while the presser foot is raised to the retracted position and the first swinging member is swung, the link connected to the first arm is free of the first arm. It only swings along an arc locus centering on the end, and no motion is transmitted to the second swing member. Therefore, the presser foot can be maintained at the retracted position. Normally, the needle bar will not move up and down if a jump device provided in this type of sewing machine is operated. Therefore, the main shaft may be kept rotating during the retreat operation.
[0014]
More specifically, the present invention moves the presser foot up and down within a predetermined range in conjunction with the operation of the needle bar, and if necessary, a retracted position further above the up and down range. The presser foot of the presser foot of the presser foot is provided with a presser foot driving cam fixed to the main shaft and supported by the base frame so as to be swingable. A first swinging member engaged with the groove via a first cam follower, and provided between the first swinging member and the cloth presser, is supported swingably with respect to the base frame. And a second oscillating member comprising a first arm extending toward the first oscillating member, a second arm extending toward the cloth pressing side, the first arm of the second oscillating member, A link between at least two or more oscillating members provided to connect the one oscillating member; A second cam follower provided at a joint opposite to the first arm of the link connected to the first arm of the second swing member among the two or more swing member links; A guide cam having an arcuate cam groove with which the second cam follower is engaged; and a guide cam swingably attached to the base frame; A guide cam swinging means for changing a position of the arcuate cam groove; and a presser foot connecting link for connecting the second arm of the second swinging member and the presser foot; When the guide cam is swung so that the second rocking member is swung up so that the presser foot is raised to the retracted position, the arc-shaped cam groove is connected to the joint on the free end side of the first arm. It is configured to match the trajectory of the center arc. It can be a sewing machine presser foot device for.
[0015]
In this cloth presser device, the above-described action can be exhibited by swinging the guide cam and changing the inclination with respect to the base frame. In order to change the position of the guide cam, it may be possible to make the guide cam slide with respect to the base frame, but in order to slide an accurate trajectory, something like a rail is required. Can be complicated. On the other hand, when the position is changed by swinging, it is only necessary to support the guide cam with a single shaft with respect to the base frame, and a simple structure is sufficient. Therefore, it is possible to achieve the characteristic operation of the present invention as described above with a simple structure. Also in this case, there is an advantage that it is not necessary to stop the main shaft during retraction.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a configuration of a sewing machine presser device 10 according to the present embodiment. FIG. 2 is an enlarged cross-sectional view showing a part thereof.
[0017]
This presser foot device 10 is mounted on a presser foot guide bar 13 fixed to a base frame 1 (see FIG. 4) via a support member 11 and slidably mounted on the presser foot guide bar 13. A cylinder 15, a cloth presser 19 supported in a state of being biased downward by a spring 17 with respect to the cylinder 15, and a cylinder 15 for moving the cylinder 15 up and down along the cloth presser guide bar 13. The link mechanism 20, the height control mechanism 40 for changing the ascent height of the presser foot 19 by the link mechanism 20, and the fixing member 51 are fixed to the main shaft 50 by the attachment member 51, and the link mechanism 20 is moved along with the rotation of the main shaft 50. A presser foot drive cam 52 to be operated is provided.
[0018]
The link mechanism 20 includes a first link 21, a second link 22, a third link 23, a fourth link 24, a fifth link 25, and a sixth link 26 from above. The first link 21 has one end 21 a fixed to the rotation shaft 31, and a cam follower 21 c attached to the other end (free end) 21 b is fitted in the cam groove 53 of the presser foot drive cam 52. The upper end 22a of the second link 22 is connected to the free end 21a of the first link 21, the rear end 23a of the third link 23 is connected to the lower end 22b of the second link 22, and the front end 23b of the third link 23 is connected to the front end 23b. All the upper ends 24a of the fourth links 24 are rotatably connected. Note that a cam follower 23c fitted to a guide cam 42 of a height control mechanism 40 described later is provided at the rear end 23a of the third link 23.
[0019]
On the other hand, the lower end 24 b of the fourth link 24 and the rear end 25 a of the fifth link 25 are fixed at a predetermined angle via the rotation shaft 32. Both the rotation shaft 32 and the above-described rotation shaft 31 are rotatably supported by the base frame 1 (see FIG. 3). An upper end 26 a of the sixth link 26 is rotatably connected to the front end 25 b of the fifth link 25, and a lower end 26 b of the sixth link 26 is rotatably connected to the upper end 15 a of the cylindrical body 15. .
[0020]
As a result of the above configuration, when the main shaft 50 rotates, the links 21 to 26 of the link mechanism 20 perform operations as indicated by arrows near the main shaft 50 and move the presser foot 19 up and down within a predetermined range. Move.
[0021]
Next, the height control mechanism 40 exemplified as means for moving the guide cam will be described.
The height control mechanism 40 includes a control plate 41 whose upper end is rotatably supported with respect to the base frame 1, a guide cam 42 fixed to the control plate 41, and a motor 43 that controls the inclination of the control plate 41. And. In the present embodiment, a motor with a non-excitation operation type electromagnetic brake is used as the motor 43. As shown in FIG. 3, the motor 43 can swing the control plate 41 at a desired angle via the pinion gear 44 and the arc-shaped rack 45 and can maintain the tilted state. An arcuate cam groove 46 is formed in the guide cam 42.
[0022]
Next, the operation of the presser foot device 10 of the present embodiment will be described. 4 and 5 show the movements of the link mechanism 20 and the presser foot 19 during the sewing operation, and reference numeral 61 in the drawings is a needle bar. The needle bar 61 is mounted on the base frame 1 so as to be movable up and down, and has a sewing needle 62 for sewing at the lower end. A driven element 63 that engages with a driving element 71 a of the needle bar driving elevating body 71 is attached to the upper end of the needle bar 61.
[0023]
The needle bar drive elevating body 71 is connected to a crank rod 73 (both shown in FIG. 1) that is moved up and down by an eccentric wheel 72 attached to the main shaft 50 via a lever crank mechanism (not shown). It moves up and down in synchronization with the rotation of the main shaft 50. On the other hand, the driving element 71a is attached to the driving element guide rod 64 so as to be movable up and down, and is attached so as to face the inside of the fitting portion 63a of the driven element 63.
[0024]
Accordingly, when the needle bar driving lift 71 moves up and down in synchronization with the rotation of the main shaft 50, the needle bar 61 also moves up and down, and the position where the sewing needle 62 penetrates the needle plate 65 and the position where it comes out of the needle plate 65. Sewing is executed by moving up and down. At this time, the presser foot driving cam 52 also rotates as the main shaft 50 rotates, and the links 21 to 26 and the presser foot 19 operate as indicated by arrows in FIG. 4 shows a state in which the needle bar 61 and the presser foot 19 are raised most during sewing, and FIG. 5 shows a state in which the needle bar 61 and the work clamp 19 are lowered most.
[0025]
In addition, the code | symbol 66 in a figure is cloth. Further, as shown in the figure, the driver guide bar 64 and the presser foot guide bar 13 are mounted in parallel, and the shaft center of the sewing needle 62, the center of the through hole 19a of the presser foot 19, and the through hole of the needle plate 65 ( The center of the needle entry position) 65a coincides. Therefore, during operation, the needle bar and the presser foot do not collide because the vertical direction of the needle bar and the center movement direction of the through hole 19a of the presser foot 19 coincide.
[0026]
Next, a change in the raised height of the presser foot 19 which is a feature of the present embodiment will be described with reference to FIG. FIGS. 6A and 6D correspond to those described with reference to FIGS. 4 and 5 and show the tilted state of the control plate 41 when an ordinary thin cloth 66 is embroidered. FIGS. 7B and 7E show the tilted state of the control plate 41 when embroidery is applied to a thicker cloth 67 (for example, a cloth laid with a urethane sheet). Further, (C) and (F) in the figure show the state of the control plate when the presser foot 19 is released to the retracted position when the embroidery frame 68 is moved. In the state where the presser foot 19 has been released to this retracted position, the arcuate cam groove 46 has a radius between the joints g1 and g2 of the fourth link 24 and the left joint g1 in the figure. It is configured so that the center coincides with the arc trajectory as the center. Therefore, in this state, even if the main shaft 50 rotates, no motion is transmitted downward from the fourth link 24, and the presser foot 19 continues to be held at the retracted position. The inclination of the control plate 41 is changed by driving the motor 43 in a predetermined direction by a predetermined amount.
[0027]
Thus, in the present embodiment, when embroidery is performed on the thick cloth 67, the motor 43 is driven so that the trailing edge 41a of the control plate 41 is smaller than the normal angle Y with respect to the vertical axis. Set to a position where (<X). As a result, the position of the cam groove 46 of the guide cam 42 changes, and the presser foot 19 moves up and down at a position higher than the state of FIG. When the embroidery frame 68 is moved, the motor 43 is driven and set so that the rear edge 41a of the control plate 41 is vertical. As a result, the presser foot 19 is raised to the retracted position.
[0028]
When the presser foot 19 is thus retracted and the movement of the embroidery frame 68 is completed, the motor 43 is driven by a predetermined amount in the direction opposite to the previous direction, and the state shown in FIG. The inclination state of the control plate 41 is changed to the state of the sewing position. As a result, embroidery can be resumed.
[0029]
By the way, in the present embodiment, the cam follower 23c provided at the rear end 23a of the third link 23 is kept engaged with the cam groove 46 of the guide cam 42 even in the retracted position. Further, since the presser foot 19 only moves in the vertical direction between the sewing position and the retracted position, the presser foot 19 is also in the retracted position or when returning from the retracted position to the sewing position. The center of the through hole 19 a coincides with the axis of the sewing needle 62. As a result, in the present embodiment, the spindle 50 can be started to rotate before the presser foot 19 is completely returned from the retracted position to the sewing position, and the waiting time from the retracted state to the restart of the embroidery can be reduced. Can do. Even if it is only a short time reduction when paying attention to only one evacuation operation, in the embroidery factory, such an evacuation operation is executed enormously in the work of one day, so the accumulated time is large. As a result, the operating rate of the sewing machine can be greatly improved. As described above, since the rotational movement of the main shaft 50 is not transmitted downward from the fourth link 24 during the retraction operation, the main shaft 50 may continue to rotate as long as the needle bar 61 is in a jump state. Absent.
[0030]
In the present embodiment, the cam follower 23c is always engaged with the arcuate cam groove 46 of the guide cam 42. For example, this is proposed in Japanese Patent Application Laid-Open Nos. 7-231991 and 6-238078. Unlike the configuration that provides a strong urging force for maintaining the engaged state with respect to the cam as in the case of what has been achieved, especially when the speed is increased, the engagement state with respect to the cam is strongly maintained. Unlike the configuration in which a strong urging force must be applied, it is not necessary to provide a strong urging force for maintaining a strong engagement state with the cam. Therefore, the load when the presser foot 19 is retracted is exclusively the load for moving the link mechanism 20, and the load during the retracting operation can be reduced as well as the load applied to the spindle during high-speed operation. . Eliminating the load caused by the urging force of these springs itself means that even if the load is not so much reduced when only one sewing machine is viewed, this is a multi-head sewing system that is often used in embroidery factories. Since the load is gradually accumulated on the main shaft, the load reduction of the sewing machine addressed to one head is cumulatively reduced.
[0031]
In the present embodiment, as the first swing member, the first link 21 that can be rotated by the rotation shaft 31 is shown, and as the second swing member, the rotation by the rotation shaft 32 is possible. The fourth link 24 and the fifth link 25 are exemplified. In the example, the fourth link 24 corresponds to the first arm, and the fifth link 25 corresponds to the second arm.
[0032]
The embodiment described above is an example when the present invention is implemented, and may be implemented in various modes. For example, the motor 43 may be other than a motor with a non-excitation operation type electromagnetic brake as long as the motor shaft does not rotate when the motor is stopped.
[0033]
【The invention's effect】
As described above, in the present invention, the presser foot is not changed by releasing the engagement between the presser foot drive cam for moving the presser foot up and down and the first swinging member, but by changing the position of the guide cam. Since the work clamp is raised to the retracted position, while the work clamp is being returned from the retracted position to the sewing position using the guide cam, the spindle is rotated again and the work clamp drive cam rotates. The first oscillating member may be oscillated, and the time until resuming sewing after retraction can be greatly shortened.
[0034]
Further, since the presser foot is retracted without releasing the engagement between the presser foot drive cam and the first swing member, it is necessary to apply a biasing force for maintaining the engagement of the cam mechanism during sewing. However, the load for evacuation is reduced and the effect of smooth movement is exhibited. This effect acts in the direction of shortening the time for retracting the cloth presser, and this can further shorten the time.
[0035]
Therefore, according to the present invention, the operating rate of the sewing machine can be improved, and when it is applied to a multi-head sewing machine, a significant increase in operating rate can be expected.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of a presser device for a sewing machine according to an embodiment.
FIG. 2 is an enlarged sectional view of a part of the presser device for the sewing machine according to the embodiment.
FIG. 3 is a perspective view showing a configuration of a height control mechanism in the embodiment.
FIG. 4 is a cross-sectional view showing a sewing operation in the embodiment.
FIG. 5 is a cross-sectional view showing a sewing operation in the embodiment.
FIG. 6 is a schematic explanatory view showing an operation state of the height control mechanism in the sewing operation and the retracting operation in the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base frame 10 Material presser of sewing machine 13 Material presser guide rod 19 Material presser 19a Through-hole 20 Link mechanism 21-26 1st-6th link 21c, 23c Cam follower 31, 32 Rotary shaft 40 Height control mechanism 41 Control board 42 Guide cam 43 Motor 46 Arc-shaped cam groove 50 Main shaft 52 Work clamp drive cam 53 Cam groove 61 Needle bar 62 Sewing needle 64 Drive element guide bar 65 Needle plate 65a Through hole 66 Cloth 67 Thick cloth 68 Embroidery frame

Claims (3)

The presser foot, the vertically moving in a predetermined range in the sewing position, if necessary, in the work holding unit of the sewing machine which is adapted to retract further to the retreat position above than the sewing position,
A presser foot drive cam fixed to the main shaft;
A first swing member that is swung within a predetermined range by the presser foot drive cam;
The link is connected to the first swing member by a link, and is also connected to the presser foot by a link, and swings itself in response to the swing operation of the first swing member, thereby moving the presser foot up and down. A link mechanism including a second rocking member to be moved , and
Have cam followers provided on the joint in said link mechanism is engaged, also with a guide cam having an arcuate cam groove for moving the cam follower provided to the joint by drawing a predetermined arcuate path,
The guide cam is configured to be movable in a plane direction parallel to the arcuate locus so that the position of the arcuate cam groove can be changed,
Further, by moving the position of the guide cam while the cam follower provided in the joint is engaged with the arc-shaped cam groove in the guide cam,
Even during the swinging operation of the first swinging member, the second swinging member is brought into a state where the presser foot is raised to the retracted position, or the presser foot is lowered to the sewing position and moved up and down within a predetermined range. A cloth presser device for a sewing machine comprising a guide cam moving means that can be put into a state . The cloth presser device for a sewing machine according to claim 1,
The second swing member includes a first arm extending toward the first swing member and a second arm extending toward the cloth presser;
Two or more links are provided between the first arm and the first swing member,
A cam follower engaged with the arcuate cam groove is provided at a joint opposite to the first arm of the link connected to the first arm;
When the guide cam moving means changes the position of the guide cam so as to swing up the second swinging member, the arc-shaped cam groove has an arc centered on the joint on the free end side of the first arm. A cloth presser device for a sewing machine, characterized in that it is configured to match the locus of the sewing machine. The presser foot, the vertically moving in a predetermined range in the sewing position, if necessary, in the work holding unit of the sewing machine which is adapted to retract further to the retreat position above than the sewing position,
A presser foot drive cam fixed to the main shaft, and a first supported by a base frame so as to be swingable, and having a free end engaged with a cam groove of the presser foot drive cam via a first cam follower. A swing member, and a first arm provided between the first swing member and the cloth presser, supported to be swingable with respect to the base frame, and extending toward the first swing member. A second swinging member having a second arm extending toward the cloth pressing side, and at least two provided to connect the first arm of the second swinging member and the first swinging member. The link between the swing member and the link connected to the first arm of the second swing member among the two or more swing member links is opposite to the first arm. A second cam follower provided at the joint;
By engaging the cam follower of the second, with the arcuate cam grooves for moving the cam follower draw a predetermined arcuate path, and, for the base frame, the position of the arcuate cam groove A guide cam configured to be movable in a plane direction parallel to the arcuate trajectory so that it can be changed ;
Guide cam swinging means for swinging the guide cam with respect to the base frame and changing the position of the arcuate cam groove;
A presser foot link that connects the second arm of the second swing member and the presser foot;
The guide cam swinging means determines the position of the guide cam.
The second swinging member sews the presser foot while the second cam follower is engaged with the arcuate cam groove and during the swinging operation of the first swinging member. A sewing machine cloth presser device which is configured to be movable to a position where it can be lowered to a position and moved up and down within a predetermined range, or the cloth presser is lifted to a retracted position. .

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