Differential feed sewing machine

Abstract

To appropriately set feed amount of a sub feed dog.SOLUTION: A differential feed sewing machine comprises: a feed mechanism 30 having a main feed dog 31 and a sub feed dog 32 that feed on a downstream side and an upstream side in a feed direction of a sewn object; a first feed adjusting mechanism 60 to adjust a sewing pitch of the main feed dog to an arbitrary size; and a second feed adjusting mechanism 80 to adjust a sewing pitch of the sub feed dog to an arbitrary size. The second feed adjusting mechanism adjusts the sewing pitch of the sub feed dog by an actuator 82 and has a setting input part 95 to set and input the sewing pitch of the sub feed dog and a control device 90 to control the actuator so that the sewing pitch becomes the sewing pitch of the sub feed dog input from the setting input part.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a differential feed sewing machine.

Background Art

[0002] A conventional differential feed sewing machine is configured with feed teeth including main feed teeth on the downstream side and sub-feed teeth on the upstream side in the feed direction, and can perform a feed operation so that a difference occurs in the sewing pitch between the main feed teeth and the sub-feed teeth. Then, by operating a manual knob or the like to set the ratio of the sewing pitch between the main feed teeth and the sub-feed teeth, a difference in the sewing pitch was provided (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above conventional differential feed sewing machine has a problem in that, after setting the sewing pitch of the main feed teeth, it is necessary to manually adjust the ratio of the sewing pitch between the main feed teeth and the sub-feed teeth, resulting in low reproducibility. In addition, since the setting is made based on the ratio of the sewing pitch between the main feed teeth and the sub-feed teeth, when it is desired to individually set the sewing pitch of the main feed teeth and the sewing pitch of the sub-feed teeth, the ratio must be obtained, which may make the setting work complicated. Furthermore, there may be a case where only the sewing pitch of the main feed teeth is to be changed while keeping the sewing pitch of the sub-feed teeth fixed. In that case, both the sewing pitch of the main feed teeth and the ratio of the sewing pitches must be reset, making the setting work complicated.

[0005] An object of the present invention is to appropriately set the feed amount of the sub-feed teeth in a differential feed sewing machine.

Means for Solving the Problem

[0006] The present invention relates to a differential feed sewing machine, and includes a feed mechanism having a main feed tooth and a sub-feed tooth that perform feeding on the downstream side and the upstream side in the feeding direction of the workpiece to be sewn, a first feed adjustment mechanism for adjusting the stitch pitch of the main feed tooth to an arbitrary size, a second feed adjustment mechanism for adjusting the stitch pitch of the sub-feed tooth to an arbitrary size, and is characterized in that the second feed adjustment mechanism adjusts the stitch pitch of the sub-feed tooth by an actuator, and includes a setting input unit for setting and inputting the stitch pitch of the sub-feed tooth, and a control device for controlling the actuator so that the stitch pitch of the sub-feed tooth input from the setting input unit is obtained.

Advantages of the Invention

[0007] With the above configuration, the present invention enables appropriate setting of the feed amount of the sub-feed tooth.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0009] [Schematic Configuration of the Embodiment] Hereinafter, the differential feed sewing machine 100 which is an embodiment of the present invention will be described in detail. FIG. 1 is a perspective view showing the whole of the differential feed sewing machine 100, FIG. 2 is a perspective view of the inside of the sewing machine seen from a direction different from that of FIG. 1, FIG. 3 is a perspective view of the inside of the sewing machine seen from a direction different from those of FIGS. 1 and 2, FIG. 4 is a right side view of the inside of the sewing machine, and FIG. 5 is a perspective view showing the inner configuration around the needle plate.

[0010] As shown in FIGS. 1 to 4, the differential feed sewing machine 100 includes a needle vertical movement mechanism 20 that moves the sewing needle 21 up and down by the rotation of the upper shaft 23, a bobbin (not shown) that winds the upper thread around the lower thread, a feed mechanism 30 that performs differential feeding of the workpiece to be sewn on the needle plate 14 in synchronization with the up and down movement of the sewing needle 21 by the main feed teeth 31 and the auxiliary feed teeth 32, a sewing machine frame 10 that supports the above respective components, and a control device 90 (see FIG. 7) that controls the above respective components. Note that the differential feed sewing machine 100 includes various components such as a balance, a thread tensioner, and a presser that are provided in a general sewing machine, but since these are well-known, the description thereof is omitted.

[0011] The sewing machine frame 10 includes a bed portion 11 located at the lower part in the whole of the differential feed sewing machine 100, a vertical cylinder portion 12 erected upward at one end portion in the longitudinal direction of the bed portion 11, and an arm portion 13 (not shown) extending from the upper end portion of the vertical cylinder portion 12 in the same direction as the bed portion 11. In the following description, the downstream side in the feeding direction of the workpiece to be sewn is referred to as "front", the upstream side in the feeding direction is referred to as "rear", the left side when facing forward is referred to as "left", the right side is referred to as "right", the upper side in the vertical direction is referred to as "up", and the lower side in the vertical direction is referred to as "down". Also, assuming that the differential feed sewing machine 100 is installed on a horizontal plane, the directions of each part of the differential feed sewing machine 100 are such that the front-rear direction and the left-right direction are horizontal.

[0012] [Needle up-and-down movement mechanism] As shown in FIG. 1, the needle up-and-down movement mechanism 20 is disposed inside the arm portion 13, and includes a main shaft 23 disposed along the left-right direction that rotates using the sewing machine motor 16 as a drive source, a needle bar 22 that holds the sewing needle 21 at the lower end portion, and a crank mechanism 24 that converts the rotational force of the main shaft 23 into a reciprocating driving force of up-and-down movement and transmits it to the needle bar. The main shaft 23 is connected to the needle bar 22 via the crank mechanism 24 at the left end portion, and the right end portion is connected to the output shaft of the sewing machine motor 16. The crank mechanism 24 has a well-known configuration, and includes a rotating weight that rotates by the main shaft 23 and a crank rod, and converts the rotation of the main shaft 23 into an up-and-down reciprocating motion and transmits it to the needle bar 22. The rotation of the main shaft 23 is transmitted to a bobbin shaft (not shown) inside the bed portion 11 by a transmission mechanism (not shown) such as a gear mechanism or a belt mechanism using bevel gears, and drives the rotation of the bobbin.

[0013] [Feeding mechanism] As shown in FIGS. 1 to 5, the feeding mechanism 30 includes a main feed tooth 31 and a sub-feed tooth 32 that protrude from and retract into the opening of the needle plate 14 to feed the workpiece to be sewn in a predetermined direction, a first feed base 33 that holds the main feed tooth 31, a second feed base 34 that holds the sub-feed tooth 32, a vertical feeding mechanism 40 that obtains power from the sewing machine motor 16 and transmits a reciprocating motion in the vertical direction to the first and second feed bases 33, 34, a first horizontal feeding mechanism 50 that imparts a reciprocating motion in the front-rear direction to the first feed base 33, and a second horizontal feeding mechanism 70 that imparts a reciprocating motion in the front-rear direction to the second feed base 34.

[0014] [Feed teeth and feed bases] As shown in Fig. 5, the main feed teeth 31 and the sub-feed teeth 32 are respectively arranged on the lower side of the needle plate 14, in front of and behind the needle drop position. In the differential feed sewing machine 100, by providing a difference between the main feed teeth 31 and the sub-feed teeth 32 in terms of the feed amount of the sewing material per stitch, i.e., the sewing pitch, the forward and backward differential feed is realized. For example, in general sewing, depending on the material of the sewing material, there may be a case where the feed amount of the upper sewing material with respect to the lower sewing material becomes small, resulting in a deviation at the end portion of the sewing. Conversely, this may also occur. In such a case, by differential feed, it is possible to provide a difference in the sewing pitch between the upper sewing material and the lower sewing material and perform proper sewing. Also, by making the sewing pitch of the rear sub-feed teeth 32 larger than that of the front main feed teeth 31, it is possible to perform tuck sewing that gives a bulge to the upper sewing material. In this way, by providing a difference in the sewing pitch between the main feed teeth 31 and the sub-feed teeth 32, various sewings can be performed.

[0015] The main feed teeth 31 are supported from below by the first feed base 33, and the sub-feed teeth 32 are supported from below by the second feed base 34. Inside the bed portion 11, the first feed base 33 and the second feed base 34 are arranged adjacent to each other such that the first feed base 33 is on the right side and the second feed base 34 is on the left side. Both the first feed base 33 and the second feed base 34 extend in the front-rear direction. A reciprocating motion along the front-rear direction is input from the front end portion of each, and a reciprocating motion along the up-down direction is input from the rear end portion at the same cycle. A reciprocating motion along the front-rear direction and a reciprocating motion along the up-down direction are combined for the main feed teeth 31 and the sub-feed teeth 32, and the motion is transmitted as an elliptical circular motion along the front-rear direction, enabling the feeding of the sewing material.

[0016] In the differential feed sewing machine 100, differential feed is realized by individually adjusting the stroke of the reciprocating motion in the front-rear direction between the main feed teeth 31 and the sub-feed teeth 32. Note that the first feed base 33 and the second feed base 34 may input a reciprocating motion in the front-rear direction from the rear end portion and a reciprocating motion in the up-down direction from the front end portion.

[0017] [Vertical feed mechanism] As shown in FIGS. 2, 3 and 5, the vertical feed mechanism 40 includes a vertical feed shaft 41 provided along the left - right direction at the rear side within the bed portion 11, an input arm 42 provided near the right end portion of the vertical feed shaft 41, a connecting rod 43 connecting the upper shaft 23 and the input arm 42, and first and second output arms 44, 45 provided side - by - side in the left - right direction near the left end portion of the vertical feed shaft 41.

[0018] The vertical feed shaft 41 is rotatably supported within the bed portion 11. The input arm 42 has a base end portion clamped and fixed to the vertical feed shaft 41, and a rotating end portion extending forward from the vertical feed shaft 41.

[0019] The connecting rod 43 extends in the vertical direction. The upper end portion is rotatably connected to an eccentric shaft portion eccentric from the rotation center of the upper shaft 23. Also, the lower end portion of the connecting rod 43 is rotatably connected to the rotating end portion of the input arm 42 around an axis along the left - right direction. The upper end portion of the connecting rod 43 performs a circular motion as the upper shaft 23 rotates due to the eccentric shaft portion, and the lower end portion inputs an up - and - down motion with a stroke twice the eccentricity of the eccentric shaft portion with respect to the upper shaft 23 to the rotating end portion of the input arm 42. The input arm 42 can input a reciprocating rotation operation to the vertical feed shaft 41 by the up - and - down movement of the rotating end portion by the connecting rod 43.

[0020] Both the first and second output arms 44, 45 are fixed to the left end portion of the vertical feed shaft 41 and have rotating end portions extending forward. And, both the first and second output arms 44, 45 have slits 441, 451 formed along the longitudinal direction on the rotating end portion side. These slits 441, 451 are both open toward the tip end portion of the rotating end portion.

[0021] The first output arm 44 holds, inside the slit 441, a roller 46 rotatably supported about an axis along the left-right direction at the rear end of the first feed table 33 so as to restrict the roller 46 in the vertical direction. Further, the second output arm 45 holds, inside the slit 451, a roller 47 rotatably supported about an axis along the left-right direction at the rear end of the second feed table 34 so as to restrict the roller 47 in the vertical direction. With this configuration, when the first and second output arms 44 and 45 reciprocally rotate vertically together with the vertical feed shaft 41, vertical movement can be input to the rear ends of the first and second feed tables 33 and 34 via the rollers 46 and 47 in the slits 441 and 451.

[0022] [First Horizontal Feed Mechanism] As shown in FIGS. 2, 3, and 5, the first horizontal feed mechanism 50 includes a first horizontal feed shaft 51 provided along the left-right direction within the bed portion 11, an input arm 52 provided at the right end portion of the first horizontal feed shaft 51, a connecting rod 53 having its upper end portion connected to the upper shaft 23, a first feed adjustment mechanism 60 for adjusting the stroke of the reciprocating motion taken out from the lower end portion of the connecting rod 53, a relay arm 54 to which the reciprocating motion is input from the first feed adjustment mechanism 60, a connecting link 55 connecting the relay arm 54 and the input arm 52, and an output arm 56 provided at the left end portion of the first horizontal feed shaft 51.

[0023] The first horizontal feed shaft 51 is rotatably supported at the front side within the bed portion 11. The first horizontal feed shaft 51 is a cylindrical body that is hollow throughout its entire length, and a second horizontal feed shaft 71 of a second horizontal feed mechanism 70, which will be described later, is inserted concentrically inside the first horizontal feed shaft 51. The second horizontal feed shaft 71 can perform a rotational motion independently of the first horizontal feed shaft 51.

[0024] At the right end portion of the first horizontal feed shaft 51, the base end portion of the input arm 52 is clamped and fixed. The input arm 52 has its rotating end portion extending downward from the first horizontal feed shaft 51.

[0025] The connecting rod 53 extends in the vertical direction, and its upper end is rotatably connected to an eccentric shaft portion that is eccentric from the rotation center of the upper shaft 23. Note that the eccentric shaft portion to which the connecting rod 53 is connected is a different eccentric shaft portion from the eccentric shaft portion to which the connecting rod 43 of the vertical feed mechanism 40 described above is connected. The lower end of the connecting rod 53 is rotatably connected to one end of the transmission link 61 of the first feed adjustment mechanism 60 about an axis along the left-right direction. Moreover, the other end of this transmission link 61 is rotatably connected to the rotating end portion of the relay arm 54 about an axis along the left-right direction.

[0026] The relay arm 54 is rotatably supported by the vertical feed shaft 41. The vertical feed shaft 41 performs a reciprocating rotation operation transmitted from the upper shaft 23, but the relay arm 54 performs a reciprocating rotation operation by the reciprocating operation input from the transmission link 61, independent of the reciprocating rotation operation of the vertical feed shaft 41. That is, the relay arm 54 may be supported by any other axis along the left-right direction, not limited to the vertical feed shaft 41.

[0027] The relay arm 54 has a rotating end portion extending downward from the vertical feed shaft 41. At the rotating end portion of the relay arm 54, the other end of the transmission link 61 and one end of the connecting link 55 are rotatably connected about the same axis along the left-right direction. Note that one end of the connecting link 75 of the second horizontal feed mechanism 70 described later is also connected on the same axis. Therefore, when a reciprocating operation is input from the transmission link 61 to the relay arm 54, a reciprocating operation is simultaneously input to one ends of the connecting links 55 and 75.

[0028] The connecting link 55 extends along the front-rear direction at the inner bottom of the vertical body portion 12. The other end of the connecting link 55 is rotatably connected to the rotating end portion of the input arm 52 facing downward about an axis along the left-right direction. Therefore, when the relay arm 54 performs a reciprocating rotation, the input arm 52 can be reciprocally rotated via the connecting link 55, and a reciprocating rotation operation is also transmitted to the first horizontal feed shaft 51.

[0029] Note that between the other end of the connecting link 55 and the pivoting end of the input arm 52, a pivot shaft (not shown) that is position - adjustable along a long hole 521 provided along the extending direction of the input arm 52 is provided. This pivot shaft can be fastened and fixed at an arbitrary position along the long hole 521 by a fastening member 522 such as a bolt. When the pivot shaft is arranged at a position separated from the pivoting center of the input arm 52, the width of the reciprocating rotation angle of the first horizontal feed shaft 51 performed by the input from the connecting link 55 is reduced. When the pivot shaft is arranged at a position close to the pivoting center of the input arm 52, the width of the reciprocating rotation angle of the first horizontal feed shaft 51 performed by the input from the connecting link 55 can be increased.

[0030] The output arm 56 is fixed to the front end of the first horizontal feed shaft 51 by clamping. The pivoting end of the output arm 56 extends upward from the first horizontal feed shaft 51. Due to the reciprocating rotation of the first horizontal feed shaft 51, the pivoting end of the output arm 56 reciprocates in the front - rear direction. The pivoting end of the output arm 56 is connected to the front end of the first feed table 33 so as to be rotatable about an axis along the left - right direction, and a reciprocating motion along the front - rear direction can be input to the front end of the first feed table 33.

[0031] [First Feed Adjustment Mechanism] FIG. 6 is a perspective view showing the main part of the first feed adjustment mechanism 60. As shown in FIGS. 2, 4, and 6, the first feed adjustment mechanism 60 includes a transmission link 61 that connects the lower end of the aforementioned connecting rod 53 and the rotating end of the relay arm 54, a pair of regulating links 62 that regulate the reciprocating motion direction of the connecting portion between the connecting rod 53 and the transmission link 61 in an arbitrary direction, a feed adjustment body 63 that rotatably supports the pair of regulating links 62 about an axis along the left-right direction, a feed adjustment dial 64 as a manual input unit for setting and inputting the sewing pitch of the main feed teeth 31, a cam member 65 that swings according to the operation of the feed adjustment dial 64, an interlocking rod 66 that swings the feed adjustment body 63 in conjunction with the swing of the cam member 65, and a potentiometer 67 as a detection unit for detecting the magnitude of the sewing pitch set by the feed adjustment dial 64.

[0032] Since the upper end of the connecting rod 53 is connected to the eccentric shaft portion of the upper shaft 23, a reciprocating motion along the vertical direction can be extracted from the lower end. One end of the transmission link 61 is rotatably connected to the lower end of the connecting rod 53 about an axis along the left-right direction, and the other end of the transmission link 61 is rotatably connected to the lower end of the relay arm 54 about an axis along the left-right direction. At this time, when the lower end of the connecting rod 53 only reciprocates in the vertical direction and does not reciprocate in the front-rear direction, almost no reciprocating motion is transmitted to the relay arm 54.

[0033] Therefore, one end of the pair of regulating links 62 is also rotatably connected to the lower end of the connecting rod 53 about an axis along the left-right direction. Since the other ends of the pair of regulating links 62 are rotatably connected to the feed adjustment body 63 about an axis along the left-right direction, the reciprocating motion direction of the lower end of the connecting rod 53 can be regulated in a direction along an arc with a radius equal to the axial distance between both ends of the regulating link 62.

[0034] The feed adjustment body 63 has a shaft portion 631 along the left - right direction and is supported in the bed portion 11 so as to be swingable around the shaft portion 631. By swinging the feed adjustment body 63 and changing its swing angle, the reciprocating motion direction of the lower end portion of the connecting rod 53 can also be changed. For example, when the swing angle of the feed adjustment body 63 is adjusted so that the regulating link 62 is in a state substantially along the front - rear direction (horizontal direction), the lower end portion of the connecting rod 53 reciprocates only in the up - down direction, and almost no reciprocating motion is transmitted to the relay arm 54. Therefore, the sewing pitch of the main feed teeth 31 becomes 0. The swing angle of the feed adjustment body 63 in this case is defined as the neutral angle.

[0035] When the feed adjustment body 63 is swung from the neutral angle in one direction, the main feed teeth 31 can be given a reciprocating motion in the direction of feeding the workpiece forward (forward feed) through the relay arm 54, the connecting link 55, etc. Also, the larger the swing angle from the neutral angle in one direction, the larger the width (sewing pitch) of the reciprocating motion of the forward feed can be. When the feed adjustment body 63 is swung from the neutral angle in the other direction, the main feed teeth 31 can be given a reciprocating motion in the direction of feeding the workpiece backward (reverse feed) through the relay arm 54, the connecting link 55, etc. Also, the larger the swing angle from the neutral angle in the other direction, the larger the width (sewing pitch) of the reciprocating motion of the reverse feed can be.

[0036] The feed adjustment dial 64 is arranged on the rear surface side of the vertical cylinder portion 12. The feed adjustment dial 64 is supported by the vertical cylinder portion 12 by a shaft portion 641 formed with a male thread and moves forward and backward in the front - rear direction by performing a rotation operation.

[0037] A cam member 65 is arranged on the front side of the shaft portion 641 of the feed adjustment dial 64. The cam member 65 is supported in the vertical cylinder portion 12 so as to be swingable around a shaft along the left - right direction. At the rear end of the cam member 65, a cam surface 651 that abuts against the shaft portion 641 of the feed adjustment dial 64 is formed. At the front end, the upper end portion of the interlocking rod 66 is connected so as to be rotatable about an axis along the left-right direction. And the lower end portion of the interlocking rod 66 is connected to the feed adjustment body 63 so as to be rotatable about an axis along the left-right direction.

[0038] The cam surface 651 of the cam member 65 can swing the cam member 65 about an axis along the left-right direction according to the movement of the shaft portion 641 of the feed adjustment dial 64 in the front-rear direction, and the feed adjustment body 63 can also be swung via the interlocking rod 66. Therefore, by rotating the feed adjustment dial 64, the feed adjustment body 63 can be freely swung, and the sewing pitch of the forward feed and reverse feed of the main feed teeth 31 can be set to an arbitrary size.

[0039] The cam member 65 is provided with a detected arm 652 that rotates about an axis along the left-right direction together with the cam member 65. The detected arm 652 has a rotating end portion extending downward, and the rotating end portion is connected to the upper end portion of a passive link 68 that is rotatably provided about an axis along the left-right direction. The lower end portion of the passive link 68 is rotatably supported within the vertical cylinder portion 12 about an axis along the left-right direction. A slit is formed in the rotating end portion of the detected arm 652 toward the outer side in the radial direction of rotation, and a pin protruding leftward at the upper end portion of the passive link 68 is inserted into the slit of the passive link 68. Therefore, when the cam member 65 and the detected arm 652 rotate, a rotating motion is also transmitted to the upper end portion of the passive link 68. And a potentiometer 67 is disposed on the front side of the passive link 68. The potentiometer 67 has a rod-shaped detection body protruding rearward, and is disposed such that the tip of the detection body abuts against the passive link 68.

[0040] There is a certain correlation between the sewing pitch of the main feed teeth 31 set by the rotational operation of the feed adjustment dial 64 and the displacement (detection amount) of the detector of the potentiometer 67 via the passive link 68 by the rotational operation of the feed adjustment dial 64. Therefore, by tabulating this correlation and comparing it with the detection amount of the potentiometer 67, the sewing pitch of the main feed teeth 31 currently set by the feed adjustment dial 64 can be detected.

[0041] [Second Horizontal Feed Mechanism] The second horizontal feed mechanism 70 imparts a reciprocating motion in the front-rear direction to the second feed table 34 from the relay arm 54 of the first horizontal feed mechanism 50. As shown in FIGS. 2, 3, and 5, the second horizontal feed mechanism 70 includes a second horizontal feed shaft 71 concentrically provided inside the first horizontal feed shaft 51, an input arm 72 provided at the right end of the second horizontal feed shaft 71, a connecting link 75 that connects the relay arm 54 and the input arm 72, a second feed adjustment mechanism 80 that adjusts the stroke of the reciprocating motion input from the connecting link 75 to the input arm 72, and an output arm 76 provided at the left end of the second horizontal feed shaft 71.

[0042] The second horizontal feed shaft 71 extends along the left-right direction, and both ends thereof protrude outward from both ends of the first horizontal feed mechanism 50. An input arm 72 extending downward is fixedly installed at the right end of the second horizontal feed shaft 71, and an output arm 76 extending upward is fixedly installed at the left end of the second horizontal feed shaft 71. And the upper end of the output arm 76 is rotatably connected to the front end of the second feed table 34 around an axis along the left-right direction. Thereby, when a reciprocating rotation is input to the input arm 72, the reciprocating rotation is transmitted to the output arm 76 through the second horizontal feed shaft 71, and the output arm 76 can impart a reciprocating motion along the front-rear direction to the second feed table 34 and the sub-feed teeth 32.

[0043] The input arm 72 has a prismatic shape, and is equipped with a rectangular frame-shaped movable connecting portion 81 of a second feed adjustment mechanism 80 to be described later in a state where the input arm 72 is inserted therethrough. And the other end of the connecting link 75 is rotatably connected to the movable connecting portion 81 about an axis along the left-right direction. That is, the connecting link 75 is connected to the input arm 72 via the movable connecting portion 81. Since the movable connecting portion 81 is movable along the input arm 72, when the connecting link 75 transmits a reciprocating motion from the relay arm 54 to the input arm 72, the reciprocating rotation stroke of the input arm 72 can be changed according to the position of the movable connecting portion 81.

[0044] [Second Feed Adjustment Mechanism] As shown in FIGS. 2 and 4, the second feed adjustment mechanism 80 includes a movable connecting portion 81 that is connected to the connecting link 75 and is supported so as to be slidable along the extending direction of the input arm 72, a sub-feed tooth adjustment motor 82 that serves as a drive source for setting and inputting the sewing pitch of the sub-feed teeth 32, an output arm 83 provided on the output shaft of the sub-feed tooth adjustment motor 82, a support shaft 84 rotatably supported by the vertical body portion 12, a driven arm 85 fixedly provided at the right end portion of the support shaft 84, a connecting link 86 that connects the output arm 83 and the driven arm 85, a traction arm 87 fixedly provided at the left end portion of the support shaft 84, and a traction link 88 that connects the rotating end portion of the traction arm 87 and the movable connecting portion 81.

[0045] As described above, the movable connecting portion 81 is movable along the input arm 72. Therefore, regarding the connection position of the connecting link 75 with respect to the input arm 72, the turning radius around the second horizontal feed shaft 71 can be expanded or contracted. The sub-feed tooth adjustment motor 82 is an actuator for arbitrarily positioning the movable connecting portion 81 along the input arm 72. The sub-feed tooth adjustment motor 82 is disposed on the upper front surface of the vertical body portion 12 with its output shaft facing rightward. The sub-feed tooth adjustment motor 82 is a motor capable of arbitrarily controlling the operation amount, such as a stepping motor, for example.

[0046] The output arm 83 is fixedly provided by clamping around the output shaft of the sub-feed tooth adjustment motor 82 with its rotating end portion facing downward. One end of the connecting link 86 is rotatably connected to the rotating end portion (lower end portion) of the output arm 83 about an axis along the left-right direction.

[0047] The driven arm 85 is fixedly mounted by clamping on a support shaft 84 along the left-right direction with the rotating end portion facing downward. And the other end of the connecting link 86 is rotatably connected to the rotating end portion of the driven arm 85 about an axis along the left-right direction. Therefore, a rotating motion is input from the output arm 83 to the driven arm 85 by driving the sub-feed tooth adjustment motor 82.

[0048] A traction arm 87 is fixedly mounted on the left end portion of the support shaft 84 with the rotating end portion facing forward. Therefore, when a rotating motion is input to the driven arm 85, the traction arm 87 can move the rotating end portion up and down via the support shaft 84. The upper end portion of the traction link 88 is rotatably connected to the rotating end portion of the traction arm 87 about an axis along the left-right direction, and the lower end portion is rotatably connected to the right side surface of the movable connection portion 81 about an axis along the left-right direction. Therefore, the movable connection portion 81 can be moved up and down along the input arm 72 as the rotating end portion of the traction arm 87 moves up and down.

[0049] When the movable connection portion 81 moves up and down by driving the sub-feed tooth adjustment motor 82, the reciprocating rotation stroke input from the relay arm 54 to the input arm 72 through the connecting link 75 varies, and the rotation operation stroke of the output arm 76 also varies, so that the sewing pitch of the sub-feed teeth 32 can be adjusted by changing. In the case of this configuration, there is a certain correlation between the shaft angle of the sub-feed tooth adjustment motor 82 and the transmission ratio of the reciprocating motion amount applied from the relay arm 54 to the sub-feed teeth 32. Also, there is a certain correlation between the reciprocating motion amount of the relay arm 54 and the sewing pitch of the main feed teeth 31. For this reason, there is also a correlation between the shaft angle of the sub-feed tooth adjustment motor 82 and the ratio of the sewing pitch of the sub-feed teeth 32 to the sewing pitch of the main feed teeth 31, and this correlation can be obtained by calculation from actual measurement or design information. Therefore, by tabulating this correlation and controlling the shaft angle of the sub-feed tooth adjusting motor 82, the ratio of the sewing pitch of the sub-feed teeth 32 to the sewing pitch of the main-feed teeth 31 can be arbitrarily set.

[0050] [Control System of Differential Feed Sewing Machine] The control system of the differential feed sewing machine 100 is shown in the block diagram of FIG. 7. As shown in FIG. 7, the control device 90 of the differential feed sewing machine 100 includes a ROM (Read Only Memory) 92 in which a program for controlling the operation of each component is stored, a RAM (Random Access Memory) 93 serving as a work area for arithmetic processing, a rewritable non-volatile data memory 94 as storage means for storing various setting data, etc., and a CPU 91 (Central Processing Unit) for executing the program in the ROM 92. The sewing machine motor 16 and the sub-feed tooth adjusting motor 82 are connected to the control device 90 via their respective motor drive circuits 16a and 82a. An encoder 161 for detecting the rotational speed of the sewing machine motor 16 is also provided, and this encoder 161 is also connected to the control device 90 via the motor drive circuit 16a. On the other hand, since the sub-feed tooth adjusting motor 82 can be arbitrarily controlled in terms of shaft angle according to the command of the control device 90, an encoder is not provided for the sub-feed tooth adjusting motor 82. However, an encoder may also be provided on the output shaft of the sub-feed tooth adjusting motor 82 to enable detection of its shaft angle. A potentiometer 67 for detecting the sewing pitch of the main-feed teeth 31 currently set by the above-described feed adjusting dial 64 is connected to the control device 90 via an interface 67a.

[0051] Furthermore, a setting input unit 95 for inputting the execution and setting of various operation controls for the differential feed sewing machine 100 is connected to the control device 90 via an interface 95a. The setting input unit 95 is composed of, for example, a liquid crystal display (LCD) with a touch panel, and functions as a display unit and an input unit. The display unit displays various setting screens, the operating state of the differential feed sewing machine, etc. according to the display control signal input from the CPU 91. The input unit consists of a touch sensor that detects touch operations applied to the display surface of the display unit, and can receive various inputs in cooperation with the input screen displayed on the display unit. For example, the setting input unit 95 can set the sewing pitch of the sub-feed teeth 32.

[0052] [Control during setting of sewing pitch] FIG. 8 is an example of the display of a setting screen G1 for setting the sewing pitch of the sub-feed teeth 32 in the setting input unit 95. As shown in the setting screen G1, the setting input unit 95 can input the sewing pitch of the sub-feed teeth 32 with a numerical value indicating the size of the pitch width. Here, "input with a numerical value indicating the size of the pitch width" means inputting a numerical value indicating the size (length) of the pitch width of the sewing pitch of the sub-feed teeth 32, and does not include the case of setting with the ratio of the sewing pitch of the sub-feed teeth 32 to the sewing pitch of the main-feed teeth 31. That is, in the setting input unit 95, in the display state of the setting screen G1, the sewing pitch of the sub-feed teeth 32 can be input with a numerical value indicating the pitch width in units of 0.1 [mm].

[0053] FIG. 9 is a flowchart showing the control performed by the CPU 91 of the control device 90 during the setting operation of the sewing pitch of the main-feed teeth 31 and the sub-feed teeth 32. This control is realized by the CPU 91 executing a control program stored in the data memory 94. Also, this control is repeatedly executed in a short cycle.

[0054] It is assumed that the sewing pitch of the main feed teeth 31 and the sewing pitch of the sub-feed teeth 32 already hold the set values that have been set as data respectively. If no setting operation has been performed in the past, it is assumed that the default value is set for the sewing pitch of the sub-feed teeth 32, and the sewing pitch of the main feed teeth 31 is read from the potentiometer 67 regularly and has been acquired in advance.

[0055] The CPU 91 determines whether a numerical value has been input for the sewing pitch of the sub-feed teeth 32 from the setting screen G1 of the setting input unit 95 (step S1). If not, the process proceeds to step S11. On the other hand, when the sewing pitch of the sub-feed teeth 32 is input, the CPU 91 reads the detected value of the potentiometer 67 of the first feed adjustment mechanism 60 (step S3), refers to the table data showing the correlation between the detected value of the potentiometer 67, the set sewing pitch of the main feed teeth 31, and acquires the current sewing pitch of the main feed teeth 31 set by the feed adjustment dial 64 (step S5).

[0056] Then, the CPU 91 calculates the ratio of the sewing pitch of the sub-feed teeth 32 set from the setting screen G1 to the current sewing pitch of the main feed teeth 31 (step S7). Then, the CPU 91 refers to the table data showing the correlation between the ratio of the sewing pitch of the sub-feed teeth 32 to the sewing pitch of the main feed teeth 31 described above and the shaft angle of the output shaft of the sub-feed adjustment motor 82, and controls the rotation of the shaft angle of the output shaft of the sub-feed adjustment motor 82 so that it becomes the ratio of the sewing pitch of the sub-feed teeth 32 set from the setting screen G1 to the current sewing pitch of the main feed teeth 31 calculated in step S7 (step S9). As a result, the shaft angle of the output shaft of the sub-feed adjustment motor 82 is adjusted so that the sewing pitch of the sub-feed teeth 32 matches the numerical value indicating the magnitude of the pitch width input from the setting screen G1, and the control ends.

[0057] On the other hand, in step S1, when it is determined that the sewing pitch of the auxiliary feed teeth 32 has not been numerically input from the setting screen G1 of the setting input unit 95, the CPU 91 reads the detected value of the potentiometer 67 of the first feed adjustment mechanism 60 (step S11), and determines whether the sewing pitch of the main feed teeth 31 has been changed (step S13).

[0058] If the sewing pitch of the main feed teeth 31 has not been changed either, the process returns to step S1. Also, when the sewing pitch of the main feed teeth 31 has been changed, a new sewing pitch of the main feed teeth 31 is obtained from the detected value of the potentiometer 67, and the recorded data of the sewing pitch of the main feed teeth 31 is updated (step S15).

[0059] Then, the CPU 91 calculates the ratio of the current sewing pitch of the auxiliary feed teeth 32 to the new sewing pitch of the main feed teeth 31 (step S17). Then, the CPU 91 refers to the table data showing the correlation between the above-mentioned ratio and the shaft angle of the output shaft of the auxiliary feed adjustment motor 82, and based on the ratio of the sewing pitch of the auxiliary feed teeth 32 to the sewing pitch of the main feed teeth 31 after the change calculated in step S17, controls the output shaft of the auxiliary feed adjustment motor 82 to rotate so that the shaft angle can maintain the currently set sewing pitch of the auxiliary feed teeth 32 (step S19). Thereby, even when only the sewing pitch of the main feed teeth 31 is changed, the sewing pitch of the auxiliary feed teeth 32 is adjusted so as to maintain the set value, and the control ends.

[0060] [Technical Effects of the Embodiment of the Invention] As described above, since the differential feed sewing machine 100 adjusts the sewing pitch of the auxiliary feed teeth 32 by the auxiliary feed adjustment motor 82, if the setting content of the sewing pitch of the auxiliary feed teeth 32 is constant, it can be adjusted to a constant sewing pitch, and compared with the case of manual adjustment, it is possible to improve the reproducibility of the feed operation during sewing.

[0061] Furthermore, the setting input unit 95 allows the setting of the stitching pitch by the sub feed dog 32 to be inputted as a numerical value indicating the size of the pitch width, so that it is possible to further improve reproducibility. Furthermore, since the setting input unit 95 is not configured to set the sewing pitch of the sub-feed dog 32 based on a ratio to the sewing pitch of the main feed dog 31, when the target pitch width of the sewing pitch of the sub-feed dog 32 required for sewing is known, there is no need to calculate it from a ratio value, which eliminates the complexity of the sewing pitch setting work and makes it possible to perform the work easily and quickly.

[0062] In addition, in the differential feed sewing machine 100, the second horizontal feed mechanism 70 is configured to obtain driving force for the reciprocating movement of the sub-feed dog 32 in the forward and backward directions by being divided midway, like the relay arm 54 of the first horizontal feed mechanism 50, and therefore, when the sewing pitch of the main feed dog 31 is changed, the sewing pitch of the sub-feed dog 32 fluctuates in tandem. Therefore, when the setting input unit for the stitch pitch of the main feed dog 31 is of a mechanical type, it may be difficult to control the stitch pitch of the sub feed dog 32 to match a target set value. For this reason, the differential feed sewing machine 100 is provided with a potentiometer 67 as a detection unit that detects the set value of the sewing pitch of the main feed dog 31, and by enabling the control device 90 to recognize the set value of the sewing pitch of the main feed dog 31, it is possible to effectively control the sewing pitch of the sub-feed dog 32 to match the target set value.

[0063] In addition, when only the sewing pitch setting of the main feed dog 31 is changed, the control device 90 controls the sub-feed dog adjustment motor 82 to maintain the sewing pitch of the sub-feed dog 32 that has already been set. Therefore, when it is desired to change only the sewing pitch of the main feed dog 31 without changing the sewing pitch of the sub-feed dog 32, proper sewing can be performed. In addition, at that time, even if one wishes to change only the sewing pitch of the main feed dog 31, there is no need to re-determine and re-set the setting of the sub feed dog 32, eliminating the complication of the setting work and enabling easy and smooth setting work.

[0064] [Others] Above, each embodiment of the present invention has been described. However, the present invention is not limited to the above embodiments. For example, in the embodiment, a component integrally formed by a single member may be replaced with a component formed by dividing a plurality of members and connecting or fixing them to each other. Further, a component formed by connecting a plurality of members may be replaced with a component integrally formed by a single member. In addition, the details shown in the embodiments can be appropriately changed without departing from the gist of the invention.

[0065] For example, in the differential feed sewing machine 100 described above, although the configuration is such that the sewing pitch of the main feed teeth 31 is adjusted by manually operating the feed adjustment dial 64, it is not limited to this. For example, a motor with a controllable operation amount may be mounted to rotate the feed adjustment body 63 around an axis along the left - right direction, and the sewing pitch of the main feed teeth 31 may be adjusted by controlling the shaft angle of the motor.

[0066] In that case, as shown in FIG. 10, a setting screen G2 that allows both the sewing pitch of the main feed teeth 31 and the sewing pitch of the sub - feed teeth 32 to be input with numerical values indicating the pitch width may be displayed on the setting input unit 95. Thereby, for both the sewing pitch of the main feed teeth 31 and the sewing pitch of the sub - feed teeth 32, any numerical value indicating the pitch width, for example, a numerical value indicating a pitch width in units of 0.1 [mm], can be input.

Explanation of Reference Numerals

[0067] 10 Sewing machine frame 14 Needle plate 16 Sewing machine motor 20 Needle up - down movement mechanism 21 Sewing needle 22 Needle bar 23 Upper shaft 30 Feed mechanism 31 Main feed teeth 32 Sub - feed teeth 33 First feed table 34 Second feed table 40 Vertical feeding mechanism 41 Vertical feed shaft 44 First output arm 45 Second output arm 50 First horizontal feeding mechanism 51 First horizontal feed shaft 54 Relay arm 56 Output arm 60 First feed adjustment mechanism 63 Feed adjustment body 64 Feed adjustment dial 67 Potentiometer (detection unit) 70 Second horizontal feeding mechanism 71 Second horizontal feed shaft 72 Input arm 80 Second feed adjustment mechanism 81 Movable connection part 82 Sub-feed tooth adjustment motor 90 Control device 91 CPU 95 Setting input part 100 Differential feed sewing machine G1, G2 Setting screen

Claims

1. A feeding mechanism having a main feeding tooth and an auxiliary feeding tooth that perform feeding on the downstream side and the upstream side in the feeding direction of the workpiece to be sewn, A first feeding adjustment mechanism for adjusting the sewing pitch of the main feeding tooth to an arbitrary size, A second feeding adjustment mechanism for adjusting the sewing pitch of the auxiliary feeding tooth to an arbitrary size, comprising: The second feeding adjustment mechanism adjusts the sewing pitch of the auxiliary feeding tooth by an actuator, A setting input unit for setting and inputting the sewing pitch of the auxiliary feeding tooth, A differential feeding sewing machine, characterized by comprising a control device that controls the actuator so that the sewing pitch of the auxiliary feeding tooth becomes the sewing pitch of the auxiliary feeding tooth input from the setting input unit.

2. The differential feeding sewing machine according to claim 1, wherein the setting input unit can input the setting of the sewing pitch of the auxiliary feeding tooth with a numerical value indicating the size of the pitch width.

3. The differential feeding sewing machine according to claim 2, wherein the control device controls the actuator so as to maintain the sewing pitch of the auxiliary feeding tooth that has already been set when only the setting of the sewing pitch of the main feeding tooth is changed.

4. The differential feeding sewing machine according to claim 3, further comprising a detection unit for detecting a set value of the sewing pitch of the main feeding tooth.

Images