Vertical feeding sewing machine

Abstract

To provide a vertical feeding sewing machine having good workability.SOLUTION: A vertical feeding sewing machine comprises: a feeding device 30 to feed a sewn object on a needle plate 14 by a feed dog from below the needle plate 14; an upper feeding device 40 to vertically move a presser foot 41 and a feed foot 42 alternately on the needle plate 14 and feed the sewn object on the needle plate 14 by the feed foot 42 from above the needle plate 14; an upper feeding height adjusting mechanism 60 to adjust height of vertical movement of the feed foot 42; and a pedal 96 capable of inputting operation by foot of an operator. The upper feeding height adjusting mechanism 60 raises the height of the vertical movement of the feed foot 42 by operation of the pedal 96.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] A vertical feed sewing machine includes a feed foot that swings in the feed direction while moving up and down on a needle plate in addition to feed teeth, and feeds the workpiece on the needle plate forward while sandwiching it from above and below (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] In a vertical feed sewing machine, when there is a step due to overlapping of workpieces or the like, the height of the up-and-down movement of the feed foot (top dead center height) may be adjusted by operating a variable up-and-down dial or a variable up-and-down switch in front of the step. In sewing, it is common to operate the feed direction while holding the workpiece with the left and right hands on both sides of the needle drop position. Therefore, in order to operate the variable up-and-down dial or the variable up-and-down switch at the step of the workpiece, it is necessary to temporarily stop sewing, which has been a problem of reduced productivity and complicated work.

[0005] On the other hand, it is also conceivable to perform sewing by adjusting the height of the up-and-down movement of the feed foot high from the beginning of sewing. However, noise is likely to occur, and in the thin part of the workpiece, the feed foot moves up and down excessively, so the sewing speed has to be reduced, and sufficient improvement in productivity could not be achieved.

[0006] An object of the present invention is to provide a vertical feed sewing machine with good workability.

Means for Solving the Problem

[0007] The present invention relates to a vertical feed sewing machine, a feeding device that feeds a workpiece on a needle plate from below the needle plate by feed teeth, a top feed device that alternately moves a presser foot and a feed foot up and down on the needle plate and feeds the workpiece on the needle plate from above the needle plate by the feed foot, a top feed height adjustment mechanism that adjusts the height of the vertical movement of the feed foot, and a pedal capable of inputting an operation by an operator's foot, wherein the top feed height adjustment mechanism raises the height of the vertical movement of the feed foot by operating the pedal.

Advantages of the Invention

[0008] With the above configuration, the present invention can provide a vertical feed sewing machine with good workability.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0010] [Schematic Configuration of Embodiment] Hereinafter, the up-and-down feeding sewing machine 100 according to an embodiment of the present invention will be described in detail. FIG. 1 is a perspective view showing the configuration around the upper feeding device 40 inside the up-and-down feeding sewing machine 100, FIG. 2 is a perspective view showing the configuration around the presser foot 41 and the feed foot 42 of the up-and-down feeding sewing machine 100, and FIG. 3 is a perspective view of the configuration around the presser foot 41 and the feed foot 42 as viewed from a direction different from that in FIG. 2.

[0011] As shown in FIGS. 1 to 3, the up-and-down feeding sewing machine 100 includes a needle vertical movement mechanism 20 that moves a needle bar 22 holding a sewing needle 21 up and down by the rotation of an upper shaft 23, a feeding device 30 that feeds a workpiece to be sewn on a needle plate 14 from below by feed teeth (not shown), an upper feeding device 40 that alternately moves the presser foot 41 and the feed foot 42 up and down on the needle plate 14 and feeds the workpiece to be sewn on the needle plate 14 from above by the feed foot 42, a sewing machine frame (not shown) that supports the above-described respective configurations, and a control device 90 (see FIG. 6) that controls the above-described respective configurations. Note that the up-and-down feeding sewing machine 100 includes various configurations such as a balance, a bobbin mechanism, and a thread tension adjustment mechanism provided in a general sewing machine, but since these are well-known, the description thereof is omitted.

[0012] The sewing machine frame includes a sewing machine bed portion located at the lower part in the entirety of the up-and-down feeding sewing machine 100, a vertical cylinder portion erected upward at one end in the longitudinal direction of the sewing machine bed portion, and a sewing machine arm portion extending in the same direction as the sewing machine bed portion from the upper end portion of the vertical cylinder portion. 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". In addition, the directions of each part of the up-and-down feeding sewing machine 100 are based on the premise that the up-and-down feeding sewing machine 100 is installed on a horizontal plane, and the front-rear direction and the left-right direction are horizontal.

[0013] [Needle Vertical Movement Mechanism] As shown in FIGS. 1 and 2, the needle vertical movement mechanism 20 is disposed inside the sewing machine arm portion. The needle vertical movement mechanism 20 includes an upper shaft 23 disposed along the left - right direction that rotates using the sewing machine motor 16 as a driving source, a needle bar 22 that holds the sewing needle 21 at its lower end, a crank mechanism 24 that converts the rotational force of the upper shaft 23 into a reciprocating driving force of vertical movement and transmits it to the needle bar 22, and a needle swing mechanism 25 that swings the lower end of the needle bar 22 along the feeding direction of the workpiece to be sewn.

[0014] The upper shaft 23 is connected to the needle bar 22 via the crank mechanism 24 at its left end, and its right end is connected to the output shaft of the sewing machine motor 16. The rotation of the upper shaft 23 is also transmitted to a bobbin shaft (not shown) inside the sewing machine bed portion by a transmission mechanism (not shown) such as a gear mechanism or a belt mechanism using bevel gears, and the bobbin is also rotationally driven.

[0015] The needle bar 22 holds two sewing needles 21 arranged side - by - side at its lower end. However, the number of sewing needles 21 is an example, and it may be one or three or more.

[0016] The crank mechanism 24 has a rotating weight 241 rotated by the upper shaft 23, a crank rod 242, and a needle bar holder 243. The upper end of the crank rod 242 is connected to a position eccentric from the rotation center of the rotating weight 241 so as to be rotatable about an axis along the left - right direction. The lower end of the crank rod 242 is connected to the needle bar holder 243. The needle bar holder 243 holds a position slightly below the upper end of the needle bar 22 by clamping. The needle bar holder 243 has a swing shaft (not shown) extending to the right, and the swing shaft is inserted and supported with respect to the lower end of the crank rod 242 so as to be rotatable about an axis along the left - right direction. With these configurations, the crank mechanism 24 can convert the rotation of the upper shaft 23 into an up - and - down reciprocating motion and apply it to the needle bar 22. Also, since the needle bar holder 243 has a swing shaft, it allows the swing of the lower end of the needle bar 22 along the front - rear direction.

[0017] The needle swinging mechanism 25 has a swinging shaft 251 that extends along the left - right direction within the sewing machine arm portion, and a swinging frame 252 that is connected to the left end portion of the swinging shaft 251 and supports a feed bar 44 that holds the feed foot 42 at its lower end portion so as to be vertically movable. The swinging shaft 251 is rotatably supported within the sewing machine arm portion, and its right end portion is connected to the upper end portion of a swinging link 33 of a feed device 30 described later. The swinging link 33 extends along the vertical movement direction within the upright cylinder portion, and with the swinging shaft 251 as the center, its lower end portion swings back and forth. The swinging shaft 251 reciprocally rotates integrally with the swinging link 33.

[0018] The swinging frame 252 is fixed to the left end portion of the swinging shaft 251 and performs a swinging operation integrally with the reciprocally rotating swinging shaft 251. As described above, since the swinging frame 252 supports the feed bar 44 so as to be vertically movable, the feed foot 42 held at the lower end portion of the feed bar 44 can be reciprocated along the front - rear direction while allowing vertical movement. Further, the swinging frame 252 has a guide groove (not shown) parallel to the feed bar 44 on the left - hand side, and a sliding block (not shown), which is a sliding body that can slide along the guide groove, is arranged. The right end portion of the swinging shaft of the above - mentioned needle bar holder 243 is inserted into this sliding block, enabling the swinging operation of the swinging frame 252 to be imparted to the needle bar 22.

[0019] Note that both the feed foot 42 and the sewing needle 21 are synchronized so as to move forward when descending, performing so - called needle feed. Also, the feed teeth described later are synchronized so as to move forward while protruding upward from the opening of the needle plate 14 when the feed foot 42 and the sewing needle 21 are descending. Therefore, the feed foot 42, the sewing needle 21, and the feed teeth perform so - called combined feed, in which they feed the workpiece integrally.

[0020] [Feed Device] As shown in FIG. 1, the feed device 30 has a well - known configuration. Mainly, the configuration related to the operation of the upper feed device 40 is illustrated, and illustration of other configurations is omitted. The feeding device 30 includes feeding teeth that protrude in and out of an opening along the front-rear direction provided in the needle plate 14 to feed the workpiece from below, a feed base that supports the feeding teeth from below, a horizontal feed shaft 34 and a vertical feed shaft that are reciprocally rotated by power transmitted from the upper shaft 23, a horizontal input arm 35 that is fixedly equipped at the right end of the horizontal feed shaft 34 and inputs a reciprocating motion to the horizontal feed shaft 34, a horizontal output arm that is fixedly equipped at the left end of the horizontal feed shaft 34 and imparts a reciprocating motion in the front-rear direction to the feed base, and a vertical output arm that is fixedly equipped at the left end of the vertical feed shaft and imparts a reciprocating motion in the up-down direction to the feed base.

[0021] A reciprocating motion in the front-rear direction is input to the feed base from the front end, and a reciprocating motion in the up-down direction is input from the rear end. These motions are combined and an elliptical motion is imparted to the feeding teeth. When moving along a part of the upper trajectory of this elliptical motion, the upper end of the feeding teeth protrudes from the opening of the needle plate 14 to feed the workpiece from below. It is also possible to configure such that a reciprocating motion in the up-down direction is input to the front end of the feed base and a reciprocating motion in the front-rear direction is input from the rear end.

[0022] The feeding device 30 further includes a connecting rod 31 that rotatably holds an eccentric cam fixedly equipped on the upper shaft 23 at the upper end, a swing link 33 whose upper end is connected to the swing shaft 251 described above, a connecting link 32 that connects the lower end of the connecting rod 31 and the vicinity of the lower end of the swing link 33, a transmission link 36 that connects the lower end of the swing link 33 and the rotating end of the horizontal input arm 35, and a feed adjuster 37 that adjusts the amount of the reciprocating motion transmitted from the upper shaft 23 to the swing link 33.

[0023] The swing link 33 extends in the vertical direction within the vertical body portion and swings in the front-rear direction with the swing shaft 251 connected to the upper end side as a support shaft. The upper end of the connecting rod 31 performs a circular motion by an eccentric cam provided on the upper shaft 23, and the lower end performs a reciprocating motion. The reciprocating motion of the lower end of the connecting rod 31 is transmitted to the swing link 33 via the connecting link 32, causing the lower end of the swing link 33 to swing along the front-rear direction. Since the lower end of the swing link 33 is connected to the horizontal input arm 35 via the transmission link 36, a reciprocating rotation operation is input to the horizontal feed shaft 34 through the horizontal input arm 35.

[0024] In the case of the above configuration, the eccentric cam provided on the upper shaft 23, the connecting rod 31, the connecting link 32, and the swing link 33 constitute a five-bar link mechanism. The feed adjuster 37 adjusts the magnitude of the swing amplitude transmitted from the upper shaft 23 to the swing link 33 by restricting the operating direction of the connecting portion between the connecting rod 31 and the connecting link 32, which is one of the five links. That is, the feed adjuster 37 has a shaft portion along the left-right direction within the sewing machine frame, and by rotating about the shaft portion, the operating direction of the connecting portion between the connecting rod 31 and the connecting link 32 can be changed, and the magnitude of the swing amplitude transmitted to the swing link 33 is changed. As a result, the amplitude of the reciprocating motion in the front-rear direction of the feed teeth on the downstream side of the power transmission of the swing link 33, that is, the stitch pitch by the feed teeth, can be adjusted.

[0025] The shaft portion of the feed adjuster 37 is connected via a link member 39 or the like from the output shaft of the feed adjustment motor 38. The feed adjustment motor 38 is composed of a stepping motor or the like capable of arbitrarily controlling the rotation angle of the output shaft. Therefore, by controlling the feed adjustment motor 38, the feed adjuster 37 can be arbitrarily rotated to arbitrarily adjust the stitch pitch by the feed teeth.

[0026] Also, since the upper end of the swing link 33 is connected with the swing shaft 251 as a support shaft, the swing frame 252 also swings integrally with the swing link 33. For this reason, when the stitch pitch of the feed teeth is adjusted by the feed adjustment motor 38, the needle swing width of the sewing needle 21 at the lower end of the needle bar 22 is also adjusted simultaneously.

[0027] [Upper Feed Device] FIG. 4 is a perspective view of the upper feed device 40, and FIG. 5 is a perspective view of the upper feed device 40 as viewed from a direction different from that in FIG. 4. As shown in FIGS. 2 to 5, the upward feeding device 40 includes a pressing foot 41, a feeding foot 42, a pressing bar 43 that holds the pressing foot 41 at its lower end, a feeding bar 44 that holds the feeding foot 42 at its lower end, an upward feeding vertical movement mechanism 50 that alternately imparts vertical movement to the pressing foot 41 and the feeding foot 42, an upward feeding height adjustment mechanism 60 that adjusts the height of the feeding foot 42 by adjusting the amplitude of the vertical movement of the upward feeding vertical movement mechanism 50, and a pressing-up mechanism 70 that pulls up the pressing foot 41 and the feeding foot 42 to release the workpiece to be sewn.

[0028] The pressing foot 41 is a so-called boat-shaped pressing foot with the rear end facing upward when viewed from the left-right direction. An opening through which the two sewing needles 21 are inserted is formed vertically through the pressing foot 41 when the needle drops. The opening of the pressing foot 41 is formed in a shape that is long in the front-rear direction so as to allow the front-rear needle swing of the two sewing needles 21.

[0029] The feeding foot 42 has a shape such that its lower part bifurcates and can straddle the pressing foot 41, and is boat-shaped with the rear end facing upward when viewed from the left-right direction. The feeding foot 42 abuts against the workpiece to be sewn on the needle plate 14 on both the left and right sides of the pressing foot 41, and moves back and forth to feed the workpiece to be sewn. Saw-tooth-shaped teeth arranged in the front-rear direction are formed at the bottom of the feeding foot 42.

[0030] The upper end of the pressing bar 43 is connected to the bell crank 51 of the upward feeding vertical movement mechanism 50 described later. The pressing bar 43 is arranged in front of the feeding bar 44 and is supported by the sewing machine arm part so as to be vertically movable along the vertical direction.

[0031] The upper end of the feeding bar 44 is connected to the bell crank 51 via a short link member 511 so as to be swingable about an axis along the left-right direction. Also, as shown in FIG. 2, the feeding bar 44 is supported by the swing frame 252 so as to be vertically movable below the upper end, and thus can perform a swing operation together with the needle bar 22 and the sewing needle 21. Also, similar to the case of the sewing needle 21 described above, when the sewing pitch of the feed teeth is adjusted by the feed adjustment motor 38, the feed width of the feed foot 42 at the lower end of the feed bar 44 is also adjusted simultaneously.

[0032] [Upper feed vertical movement mechanism] As shown in FIGS. 2 to 5, the upper feed vertical movement mechanism 50 includes a bell crank 51 having three connecting portions, a support frame 52 that rotatably supports the bell crank 51, a support cylinder 53 that vertically movably supports the support frame 52, a connecting rod 54 having one end connected to the upper shaft 23 via an eccentric cam, an upper feed shaft 57 extending in the left-right direction, an input arm 56 fixedly provided near the right end of the upper feed shaft 57, a connecting link 55 that connects the other end of the connecting rod 54 and the rotating end of the input arm 56, an output arm 58 fixedly provided at the left end of the upper feed shaft 57, and a transmission link 59 that connects the rotating end of the output arm 58 and one of the connecting portions of the bell crank 51.

[0033] One end of the connecting rod 54 performs a circular motion by an eccentric cam provided on the upper shaft 23, and the other end performs a reciprocating motion. The reciprocating motion of the other end of the connecting rod 54 is transmitted to the input arm 56 via the connecting link 55, and a reciprocating rotational motion is input to the upper feed shaft 57. Furthermore, due to the reciprocating rotational motion of the upper feed shaft 57, the output arm 58 also performs a reciprocating rotational motion, and a reciprocating rotational motion can be input to the bell crank 51 from the rotating end of the output arm 58 via the transmission link 59.

[0034] The bell crank 51 has connecting portions at the upper part, the lower front side, and the lower rear side. The connecting portion at the upper part of the bell crank 51 is connected to the transmission link 59 so as to be rotatable about an axis along the left-right direction. The connecting portion at the lower front side of the bell crank 51 is connected to the upper end of the pressing bar 43 so as to be rotatable about an axis along the left-right direction. Also, the bell crank 51 is supported by the support frame 52 at the connecting portion at the lower front side so as to be rotatable about an axis along the left-right direction. The connecting portion on the lower rear side of the bell crank 51 is connected to the upper end portion of the feed bar 44 via a short link member 511. Both end portions of this link member 511 are connected to the bell crank 51 and the feed bar 44 so as to be rotatable about an axis along the left - right direction.

[0035] The support frame 52 that supports the bell crank 51 has its upper end portion formed in a shaft shape along the vertical direction and is inserted and supported at the lower end portion of the support cylinder 53. A pressing spring 531 is inserted between the support cylinder 53 and the shaft - shaped upper end portion of the support frame 52, and a downward pressing force is applied to the support frame 52. And a downward pressing pressure is applied to the pressing bar 43 and the pressing foot 41 from the support frame 52 via the bell crank 51.

[0036] In the above - described configuration, as the upper shaft 23 rotates, the output arm 58 performs a reciprocating rotational motion in the up - and - down mechanism 50. At this time, when the lower end portion of the output arm 58 rotates forward, the connecting portion at the upper part of the bell crank 51 rotates forward via the transmission link 59, and the pressing bar 43 and the pressing foot 41 are pressed against the workpiece to be sewn on the needle plate 14. On the other hand, the bell crank 51 rotates with the connecting portion at the lower front side as a fulcrum, and the connecting portion at the lower rear side is pulled upward. Thereby, the feed foot 42 is also pulled upward via the feed bar 44.

[0037] Also, when the lower end portion of the output arm 58 rotates backward, the connecting portion at the upper part of the bell crank 51 rotates backward via the transmission link 59, and the feed bar 44 and the feed foot 42 are pressed against the workpiece to be sewn on the needle plate 14. On the other hand, the bell crank 51 rotates with the connecting portion at the lower rear side as a fulcrum, and the connecting portion at the lower front side is pulled upward. Thereby, the pressing foot 41 is also pulled upward via the pressing bar 43.

[0038] In this way, by the bell crank 51 performing a reciprocating swing, the pressing foot 41 and the feed foot 42 can be moved up and down alternately. Incidentally, the oscillating motions of the feed bar 44 and the feed foot 42 described above are synchronized so that they oscillate forward when they descend and oscillate backward when they ascend. Further, the output arm 58 and the support cylinder 53 are connected by a link member (not shown), and are configured to push up the support cylinder 53 when the feed bar 44 and the feed foot 42 oscillate forward. Thereby, when the feed bar 44 and the feed foot 42 feed the workpiece forward, the feed foot 42 is configured to contact the workpiece with a pressing force smaller than the pressing force applied to the workpiece by the presser foot 41.

[0039] [Upper feed height adjustment mechanism] As shown in FIGS. 4 and 5, the upper feed height adjustment mechanism 60 includes a vertical movement adjustment body 62 rotatably supported about an axis along the left-right direction within the sewing machine arm portion, a restricting link 61 connecting the connecting portion of the connecting rod 54 and the connecting link 55 of the upper feed vertical movement mechanism 50 to the vertical movement adjustment body 62, an input arm 65 fixedly provided on a shaft portion 621 of the vertical movement adjustment body 62, a vertical movement adjustment motor 63 serving as a drive source for rotating the vertical movement adjustment body 62, and a rotary plate 64 provided on the output shaft of the vertical movement adjustment motor 63.

[0040] The input arm 65 provided on the shaft portion of the vertical movement adjustment body 62 has a boss-like protrusion protruding rightward (not shown) near the rotating end portion, and can be fitted into a notch 641 formed in the rotary plate 64. The input arm 65 is connected to a spring 651 that biases the rotating end portion to rotate clockwise when viewed from the right, and due to the tension of the spring 651, the boss-like protrusion can be fitted into the deepest portion of the notch 641 of the rotary plate 64. In this state, by driving with the vertical movement adjustment motor 63, the vertical movement adjustment body 62 can be rotated about the shaft portion 621.

[0041] The upper feed vertical movement mechanism 50 described above is composed of an eccentric cam provided on the upper shaft 23, a connecting rod 54, a connecting link 55, and an input arm 56 to form a five-link mechanism. The vertical movement adjuster 62 can regulate the movement direction of the connecting part between the connecting rod 54 (which is one of the five segments) and the connecting link 55 via the regulating link 61. According to the rotation angle of the vertical movement adjuster 62, the movement direction of the connecting part between the connecting rod 54 and the connecting link 55 also varies, thereby enabling the variation of the amplitude of the reciprocating rotation of the output arm 58. Therefore, it is possible to variably adjust the height of the vertical movement of the pressing foot 41 and the feed foot 42 from the output arm 58, that is, the height of the top dead center of the vertical movement.

[0042] The vertical movement adjustment motor 63 is composed of a stepping motor or the like capable of arbitrarily controlling the rotation angle of the output shaft. Therefore, by controlling the vertical movement adjustment motor 63, the height of the vertical movement of the pressing foot 41 and the feed foot 42 can be arbitrarily adjusted.

[0043] [Pressing-up mechanism] The pressing-up mechanism 70 is a mechanism that raises the pressing foot 41 and the feed foot 42 to a height separated from the needle plate 14 when setting the workpiece on the needle plate 14 at the start of sewing or releasing the workpiece at the end of sewing. As shown in FIG. 5, the pressing-up mechanism 70 includes a pressing-up motor 71 serving as a driving source for pressing-up, a small-diameter output gear 72 equipped on the output shaft of the pressing-up motor 71, a large-diameter driven gear 73 meshing with the output gear 72, a pressing-up shaft 74 fixedly supporting the driven gear 73, and a hook-shaped pressing-up arm 75 provided at the left end of the pressing-up shaft 74.

[0044] The pressing-up motor 71 is disposed inside the sewing machine arm portion with its output shaft facing leftward, and the output gear 72 rotates around the output shaft along the left-right direction. The pressing-up shaft 74 extends along the left-right direction and is rotatably supported inside the sewing machine arm portion. The driven gear 73 is fixedly equipped near the right end of the pressing-up shaft 74 and rotates integrally with the pressing-up shaft 74. Therefore, by driving the pressing-up motor 71, rotation is transmitted from the output gear 72 to the driven gear 73, and the pressing-up shaft 74 can be rotated. Since the pitch circle of the driven gear 73 is sufficiently larger than that of the output gear 72, the pressing-up shaft 74 can be rotated with a large torque.

[0045] The pressing-up arm 75 has a hook-shaped rotating end and extends rearward. The rotating end of the pressing-up arm 75 can be brought into contact with the downward contact surface 521 formed on the support frame 52 of the up-feed vertical movement mechanism 50 from below. Therefore, by driving the pressing-up motor 71 and rotating the rotating end of the pressing-up arm 75 through the pressing-up shaft 74 while being in contact with the contact surface 521 of the support frame 52 from below, the pressing foot 41 and the feed foot 42 can be pushed upward through the support frame 52. As described above, since torque is increased and the rotational force is transmitted to the pressing-up shaft 74, the pressing-up arm 75 can quickly push up the pressing foot 41 and the feed foot 42 against the pressing spring 531.

[0046] [Control System of Vertical Feed Sewing Machine] The control system of the above vertical feed sewing machine 100 is shown in the block diagram of FIG. 6. As shown in FIG. 6, the control device 90 of the vertical 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 that serves as a work area for arithmetic processing, a rewritable non-volatile data memory 94 as a storage means for storing various setting data, etc., and a CPU 91 (Central Processing Unit) that executes the program in the ROM 92. And to this control device 90, a sewing machine motor 16, a feed adjustment motor 38, a vertical movement adjustment motor 63, and a pressing-up motor 71 are connected via respective motor drive circuits 16a, 38a, 63a, 71a.

[0047] In addition, an encoder 161 for detecting the rotational speed is provided in the sewing machine motor 16, and this encoder 161 is also connected to the control device 90 via the motor drive circuit 16a. Also, the feed adjustment motor 38, the vertical movement adjustment motor 63, and the presser lifting motor 71 have a home position sensor (not shown), and the shaft angle of the output shaft is arbitrarily controlled based on the detected home position. However, these motors 38, 63, 71 may also be configured to have an encoder instead of the home position sensor.

[0048] In addition, a thread cutting solenoid 17, which is a drive source of a thread cutting device (not shown), is connected to the control device 90 via a drive circuit 17a. Furthermore, a setting input unit 95 for inputting the execution and setting of various operation controls for the vertical 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: Liquid Crystal Display) 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 vertical 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 a touch operation 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.

[0049] For example, the setting input unit 95 can set the stitch pitch, sewing speed (rotational speed of the sewing machine motor 16 during sewing), the height of the top dead center of the vertical movement of the feed dog 42 (amplitude of the vertical movement), etc. during sewing of the workpiece. Also, the sewing speed and the height of the top dead center of the vertical movement of the feed dog 42 may be set stepwise with a plurality of values respectively. Here, a case is exemplified where the sewing speed can be set in two steps of high speed and low speed, and the height of the top dead center of the vertical movement of the feed dog 42 can be set in two steps of high position and low position.

[0050] Note that the high sewing speed corresponds to the normal sewing speed, and the low sewing speed corresponds to a speed suitable for cases where it is difficult to sew at high speed, such as in curved parts, corners, or stepped parts. Also, regarding the height of the top dead center of the vertical movement of the feed foot 42, the low position corresponds to the height during normal sewing for a flat workpiece, but it may also be the minimum height required for the feeding operation of the feed foot 42 for a flat workpiece. Also, the high position corresponds to a height that can overcome steps or the like on the workpiece, for example, a height that can overcome a height difference of about the thickness of a thick workpiece.

[0051] In addition, a pedal 96 for an operator to input various commands for the vertical feed sewing machine 100 with the foot is connected to the control device 90 via an interface 96a. FIG. 7 is an explanatory diagram showing the functions of the pedal 96. This pedal 96 can be depressed in two steps in the direction where the front side of the pedal plate descends from the neutral position and in two steps in the direction where the rear side of the pedal plate descends, and is biased by a spring so as to return to the neutral position without applying force to the pedal plate. As described above, this pedal 96 has five positions consisting of a neutral position P0, a first forward step P1, a second forward step P2, a first backward step P3, and a second backward step P4, and operations to be executed by the vertical feed sewing machine 100 are set for each position.

[0052] A basic setting example of the pedal will be described. The stop of the sewing machine is set at the neutral position P0 of the pedal 96. For example, when the pedal 96 is returned to the neutral position P0 during sewing, the CPU 91 stops the sewing machine motor 16. Sewing at a low sewing speed is set at the first forward step P1 of the pedal 96. For example, when the pedal 96 is depressed to the first forward step P1, the CPU 91 executes sewing while driving the sewing machine motor 16 at the set low sewing speed. Sewing at a high sewing speed is set at the second forward step P2 of the pedal 96. For example, when the pedal 96 is depressed to the second forward step P2, the CPU 91 executes sewing while driving the sewing machine motor 16 at the set high sewing speed. For the first stage P3 of the back pedal of the pedal 96, the execution of pressing up is set. For example, when the pedal 96 is depressed to the first stage P3 of the back pedal, the CPU 91 drives the pressing-up motor 71 in the upward pressing direction of the pressing foot 41 to move the pressing foot 41 and the feed foot 42 upward to a predetermined position. For the second stage P4 of the back pedal of the pedal 96, the execution of thread cutting is set. For example, when the pedal 96 is depressed to the second stage P4 of the back pedal, the CPU 91 drives the thread cutting solenoid 17 to execute thread cutting by the thread cutting device.

[0053] Furthermore, in this up-and-down feed sewing machine 100, when the pedal 96 is depressed to the second stage P2 of the front pedal, the CPU 91 controls the up-and-down movement adjustment motor 63 along with the high-speed drive of the sewing machine motor 16 to adjust the shaft angle so that the height of the top dead center of the up-and-down movement of the feed foot 42 becomes a low position. Also, in this up-and-down feed sewing machine 100, when the pedal 96 is depressed to the first stage P1 of the front pedal, the CPU 91 controls the up-and-down movement adjustment motor 63 along with the low-speed drive of the sewing machine motor 16 to adjust the shaft angle so that the height of the top dead center of the up-and-down movement of the feed foot 42 becomes a high position.

[0054] Note that the CPU 91 may be configured to execute the control for switching the high position of the top dead center of the up-and-down movement of the feed foot 42 in addition to the low-speed drive of the sewing machine motor 16 only when switching from the second stage P2 of the front pedal to the first stage P1 of the front pedal of the pedal 96. That is, when the pedal 96 is depressed from the neutral position to the first stage P1 of the front pedal, the CPU 91 performs control to keep the height of the top dead center of the up-and-down movement of the feed foot 42 at a low position in addition to the low-speed drive of the sewing machine motor 16, and when the pedal 96 is depressed from the second stage P2 of the front pedal to the first stage P1 of the front pedal, the CPU 91 may perform control to make the height of the top dead center of the up-and-down movement of the feed foot 42 a high position in addition to the low-speed drive of the sewing machine motor 16.

[0055] [Operation Control for Pedal Operation] The operation control executed by the CPU 91 of the control device 90 for the operation of the pedal 96 in the above-described up-and-down feed sewing machine 100 will be described based on the flowchart shown in FIG. 8.

[0056] First, the CPU 91 determines the presence or absence of an input signal of the first stage P1 of the forward pedal step of the pedal 96 (step S1). If the input signal is present, the sewing machine motor 16 is driven at a low speed (step S3), and the vertical movement adjustment motor 63 is controlled so that the height of the top dead center of the vertical movement of the feed dog 42 becomes a high position (step S5), and the process returns to step S1.

[0057] On the other hand, if the input signal of the first stage P1 of the forward pedal step of the pedal 96 is not present, the CPU 91 determines the presence or absence of an input signal of the second stage P2 of the forward pedal step of the pedal 96 (step S7). If the input signal is present, the sewing machine motor 16 is driven at a high speed (step S9), and the vertical movement adjustment motor 63 is controlled so that the height of the top dead center of the vertical movement of the feed dog 42 becomes a low position (step S11), and the process returns to step S1.

[0058] On the other hand, if the input signal of the second stage P2 of the forward pedal step of the pedal 96 is not present, the CPU 91 determines the presence or absence of an input signal of the first stage P3 of the backward pedal step of the pedal 96 (step S13). If the input signal is present, the presser raising motor 71 is driven, and the presser foot 41 and the feed dog 42 are raised to a predetermined height (step S15), and the process returns to step S1.

[0059] On the other hand, if the input signal of the first stage P3 of the backward pedal step of the pedal 96 is not present, the CPU 91 determines the presence or absence of an input signal of the second stage P4 of the backward pedal step of the pedal 96 (step S17). If the input signal is present, the thread cutting solenoid 17 is driven to execute thread cutting (step S19), and the process returns to step S1.

[0060] On the other hand, if the input signal of the second stage P4 of the backward pedal step of the pedal 96 is not present, the CPU 91 determines that the pedal 96 is in the neutral position P0, stops the sewing machine motor 16 to stop sewing (step S21), and returns the process to step S1.

[0061] The CPU 91 repeats the above processing until, for example, the main power switch of the sewing machine is turned off.

[0062] [Technical Effects of Embodiments of the Invention] As described above, the up-and-down feed sewing machine 100 can adjust the height of the vertical movement of the feed dog 42 to a "high position" higher than the "low position", which is a preset height, by operating the pedal 96. Therefore, it is possible to switch the feed dog 42 to the high position from the pedal 96 while operating the feeding direction while holding the workpiece with both hands on both sides of the needle drop position. When there are steps due to overlapping of workpieces, etc., it is not necessary to temporarily stop sewing and operate the variable vertical amount dial or the variable vertical amount switch. Therefore, it is possible to provide an up-and-down feed sewing machine that maintains high productivity and has good workability. In addition, when there are steps or the like, it is possible to switch the feed dog 42 to the high position and perform sewing only when necessary, and it is also possible to minimize the generation of noise and vibration.

[0063] The up-and-down feed sewing machine 100 is also provided with a control device 90 that controls the vertical movement adjustment motor 63 as an actuator of the upward feed height adjustment mechanism 60 in response to the operation of the pedal 96. This makes it easy to arbitrarily change the height settings for the high position and the low position of the feed dog 42, and it is possible to improve versatility. In addition, the up-and-down feed sewing machine 100 has a configuration suitable for automation, and it is possible to reduce the constraints on the timing of changing the height of the top dead center of the vertical movement of the feed dog 42.

[0064] In addition, the CPU 91 of the control device 90 controls the rotational speed of the sewing machine motor 16 and controls the vertical movement adjustment motor 63 so as to switch the height of the vertical movement of the feed dog 42 to a high position higher than the low position, which is a preset height, in response to an input that sets the sewing speed from the pedal 96 to a low speed lower than the high speed, which is a preset speed. When the height of the vertical movement of the feed dog 42 is switched to a high position, vibrations and noise are likely to occur, so it is desirable to also reduce the sewing speed. However, in the case of the above configuration, it is not necessary to perform each of the input operations for switching the height of the vertical movement of the feed dog 42 to a high position and the input operation for switching the sewing speed to a low speed, and one input operation on the pedal 96 is sufficient. Therefore, the sewing machine operator does not need to perform two operations, eliminating complexity and making it possible to improve operability.

[0065] [Others] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. For example, in the embodiments, components integrally formed by a single member may be replaced with components divided into a plurality of members and connected or fixed to each other. Also, components configured by connecting a plurality of members may be replaced with components 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.

[0066] For example, although the pedal 96 has been exemplified as having five positions, it is not limited to this, and the number of positions can be increased or decreased. For example, it may be possible to input only the execution and stop of sewing of the up and down feed sewing machine 100 and the switching of the height of the top dead center of the vertical movement of the feed dog 42. Furthermore, the start of sewing of the sewing machine may be performed from another input means, and the pedal may be configured to be able to input only the switching of the height of the top dead center of the vertical movement of the feed dog 42. Alternatively, regardless of the number of positions of the pedal, if there is an empty position, a setting for performing only the input of the switching of the height of the top dead center of the vertical movement of the feed dog 42 may be assigned. In that case, for the position for inputting the low-speed drive of the sewing machine motor 16, the CPU 91 may be configured to execute only the low-speed drive of the sewing machine motor 16 and not perform the switching to the high position of the top dead center of the vertical movement of the feed dog 42.

[0067] Further, the pedal 96 may be configured such that the tilt angle varies steplessly instead of having a structure that switches positions step by step. In that case, the pedal 96 may be configured to solely input the change in the top dead center of the vertical movement of the feed dog 42, and the CPU 91 may control to change the top dead center of the vertical movement of the feed dog 42 steplessly according to the tilt angle of the pedal 96.

[0068] Also, in the above-described vertical feed sewing machine 100, the height of the top dead center of the vertical movement of the feed dog 42 of the pedal 96 is set in two steps of "low position" and "high position", but only the "low position" may be set, and when increasing the height of the top dead center of the vertical movement of the feed dog 42, it may be configured to automatically determine the "high position" by adding a specified value.

[0069] Also, when a command to lower the sewing speed is input from the pedal 96 or a command to increase the height of the top dead center of the vertical movement of the feed dog 42 is input from the pedal 96 as in the above-described embodiment, etc., in a predetermined case, the CPU 91 of the control device 90 may perform control to increase the height of the top dead center of the vertical movement of the feed dog 42 by adding a specified value to the current height.

[0070] Also, in the above-described embodiment, an example of a configuration in which the CPU 91 of the vertical feed sewing machine 100 receives a signal from the pedal 96 and performs control is shown, but it is not limited thereto. For example, the pedal and the vertical movement adjustment body 62 of the upper feed height adjustment mechanism 60 may be mechanically connected by a wire, a link, or the like, and when the pedal is depressed, the vertical movement adjustment body 62 may rotate to an axial angle at which the top dead center of the vertical movement of the feed dog 42 is at a high position. In this case, for the change in the top dead center of the vertical movement of the feed dog 42, a configuration for detecting with an electric signal and a configuration for controlling an actuator such as a motor based on the detection can be made unnecessary.

[0071] Also, in the above-described embodiment, a comprehensive feed sewing machine is exemplified as the vertical feed sewing machine 100, but a configuration in which the height of the feed dog 42 is adjusted by the pedal 96 may be applied to a vertical feed sewing machine that does not perform needle feed.

Description of Reference Numerals

[0072] 14 Needle plate 16 Sewing machine motor 20 Needle up-and-down movement mechanism 21 Sewing needle 22 Needle bar 23 Upper shaft 30 Feeding device 40 Upper feeding device 41 Presser foot 42 Feed foot 43 Presser bar 44 Feed bar 50 Upper feeding up-and-down movement mechanism 60 Upper feeding up-and-down movement adjustment mechanism 62 Up-and-down movement adjustment body 63 Up-and-down movement adjustment motor (actuator) 70 Presser lifting mechanism 71 Presser lifting motor 90 Control device 91 CPU 100 Up-and-down feeding sewing machine

Claims

1. A feeding device that feeds the workpiece on the needle plate from below the needle plate by a feed tooth, An upper feeding device that alternately moves a presser foot and a feed foot up and down on the needle plate and feeds the workpiece on the needle plate from above the needle plate by the feed foot, An upper feeding height adjustment mechanism that adjusts the height of the up-and-down movement of the feed foot, A pedal capable of inputting an operation by an operator's foot, A top-and-bottom feeding sewing machine, characterized in that the upper feeding height adjustment mechanism raises the height of the up-and-down movement of the feed foot by operating the pedal.

2. The upper feeding height adjustment mechanism has an actuator that adjusts the height of the up-and-down movement of the feed foot, The top-and-bottom feeding sewing machine according to claim 1, further comprising a control device that controls the actuator of the upper feeding height adjustment mechanism so as to raise the height of the up-and-down movement of the feed foot according to the operation of the pedal.

3. The pedal can input an adjustment of the sewing speed, The control device controls the rotational speed of the sewing machine motor and controls the actuator of the upper feeding height adjustment mechanism so that the height of the up-and-down movement of the feed foot becomes higher than a predetermined height in response to an input from the pedal to make the sewing speed lower than a predetermined speed. The top-and-bottom feeding sewing machine according to claim 2.

4. The pedal can be input to a plurality of positions step by step, and an input for adjusting the height of the up-and-down movement of the feed foot is assigned to any one of the plurality of positions, The top-and-bottom feeding sewing machine according to claim 2, characterized in that when the control device receives an input for adjusting the height of the up-and-down movement of the feed foot from the pedal, the control device controls the actuator of the upper feeding height adjustment mechanism so that the height of the up-and-down movement of the feed foot becomes higher than a predetermined height.

Images