Clamping mechanism and sewing machine

Abstract

Clamping mechanism (30; 50) of a sewing machine (100), comprising: a plurality of clamping units (40A, 40B, 40C, 40D; 60A, 60B, 60C), each comprising: (i) a pair of clamping members (41, 42; 61, 62) which clamp a workpiece, and (ii) a holding block (64) which holds the pair of clamping members (41, 42; 61, 62); and a frame (31; 51) with which the retaining blocks (64) are fitted together, wherein the frame (31; 51) has at least one elongated pass hole (32, 33, 34, 35; 52, 53, 54, 55) which is formed along a curved line or along a plurality of straight lines along the curved line, and wherein the majority of clamping units (40A, 40B, 40C, 40D; 60A, 60B, 60C) are positionally adjustable along the at least one pass hole (32, 33, 34, 35; 52, 53, 54, 55) of the frame (31, 51).

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a clamping mechanism of a sewing machine at the time of sewing a workpiece of curved surface and a sewing machine having the clamping mechanism. State of the art

[0002] In sewing shoes, for example, an upper of the shoes comprising two links, which are a left link and a right link, is formed into a ring-like shape by sewing together a toe portion and a heel portion, and a sewing-on part, such as a label or a stiffening part, is sewn onto the outside of the heel portion.

[0003] The heel area of ​​the shoe upper must be finished with a curved surface according to the shape of the heel of the foot. However, to perform sewing operations in a state where the upper is curved, a so-called post-bed sewing machine has been used. A shuttle and a needle plate are arranged upward from the upper surface of a bed area, allowing both sides to be curved away from the stitching position of the fabric.

[0004] Regarding the workpiece having the curved surface, for example, the heel portion of the upper of the shoe, there is still a need to perform a sewing process with automatic feeding according to a pattern corresponding to an external shape of the part to be sewn.

[0005] However, a sewing machine for performing automatic feed sewing according to a predetermined pattern typically performs sewing by placing a workpiece on a flat surface and moving the workpiece per stitch according to plane coordinates. Thus, such a sewing machine was unsuitable for sewing the upper of the shoe with the curved surface.

[0006] To address this problem, the prior art sewing machine comprises a cylindrical holding body which holds the workpiece having the curved surface, and a stepping motor which arbitrarily rotates the holding body, thus achieving automatic feeding sewing according to a circumferential surface (see, for example, JP S61-265169 A).

[0007] DE 25 24 238 A1 discloses a machine for forming seams on workpieces. WO 2014 / 060 909 A1 describes methods and devices for loading and transferring tubular textile products. Methods and devices for machine sewing pantyhose with a comfort gusset are disclosed in DE 39 38 768 A1. DE 10 2010 038 698 A1 discloses a door gripper for a vehicle and a manufacturing method using such a door gripper. A universal clamping device is described in DE 83 19 653 U1. Summary of the invention

[0008] However, since the sewing machine according to the state of the art was designed to set the cylindrical holding body in rotation, the problem arose that the size of the mechanisms increased and thus the entire sewing machine became larger in size.

[0009] Because the size of the cylindrical holding body was fixed, a plurality of small and large holding bodies should be provided to perform a sewing operation on workpieces with a plurality of sizes.

[0010] In particular, if the workpieces were shoes, a number of different sized holding bodies should be provided due to the fine division of the sizes of the shoes and the differences between the right and left sides.

[0011] An object of the invention is to provide a clamping mechanism capable of performing a sewing operation on various curved surfaces and a sewing machine having the clamping mechanism. (1) A clamping mechanism of a sewing machine includes a plurality of clamping units and a frame. Each of the plurality of clamping units includes (i) a pair of clamping members that clamp a workpiece, and (ii) a holding block that holds the pair of clamping members. The holding blocks are fitted to the frame. The frame has at least one elongated fitting hole formed along a curved line or along a plurality of straight lines along the curved line. The plurality of clamping units are positionally adjustable and fitted along the at least one fitting hole of the frame. (2) The clamping mechanism according to (1), wherein the clamping member has a clamping surface comprising a single or a plurality of flat surfaces. (3) The clamping mechanism according to (1), wherein the clamping member has a clamping surface comprising a single curved surface. (4) The clamping mechanism according to any one of (1) to (3), wherein the pair of clamping members extend toward an opposite side of the frame with respect to the support block. The support block supports the pair of clamping members in a positionally adjustable manner along an extension direction of the pair of clamping members. (5) The clamping mechanism according to any one of (1) to (4) further comprises a release guide. The release guide releases a vertical extension area from a stitching point position. The vertical extension area extends vertically away from the workpiece clamped by the clamping members. (6) A sewing machine comprises an oscillation mechanism, a wave-line movement mechanism, and a controller. The oscillation mechanism oscillates the clamping mechanism according to any one of (1) to (5) around a wave line. The wave line lies within a curved line of at least one fitting hole of the frame. The wave-line movement mechanism moves the clamping mechanisms and a needle bar relative to each other along the wave line of the clamping mechanism. The controller controls a drive source of the oscillation mechanism and a drive source of the wave-line movement mechanism to perform stitch formation at a position of the workpiece. (7) The sewing machine according to (6) further comprises an intermediate presser. The intermediate presser moves vertically in conjunction with the needle bar. (8) The sewing machine according to (7) further comprises a throat plate. Stitch formation is performed on the throat plate. A projection portion is provided at a stitch point position of the throat plate for pressing the workpiece from above and below in cooperation with the descending intermediate presser.

[0012] According to the invention, the plurality of clamping units for holding the workpiece are positionally adjustable and fitted along one or the plurality of elongated fitting holes formed along the curved line. Therefore, the workpiece can be held along the curved surface, and it is possible to suppress the occurrence of wrinkles or fluttering of the thread after sewing in the workpiece with the curved surface, thereby achieving excellent sewing.

[0013] Since each of the clamp units is fitted positionally adjustable along the fitting hole, the ring-shaped workpiece of different sizes can be excellently held by changing the unit interval, and there is no need to provide a plurality of clamp mechanisms of different sizes.

[0014] Since each of the clamping units is adjustable in position along the fitting hole, excellent sewing can also be carried out on various workpieces with different curvature radii by adjusting the position.

[0015] A cylindrical holding body is unnecessary and thus the size of the sewing machine can be reduced. Short description of the characters Fig. 1 is a perspective view of a sewing machine according to an embodiment of the invention. Fig. 2 is a perspective view of the sewing machine according to the embodiment of the invention following movement of a table. Fig. 3 is a block diagram showing a control system of the Fig. 1 shows the sewing machine shown. Fig. 4 is a perspective view of a first clamping mechanism mounted on the sewing machine. Fig. 5 is a front view of the first clamping mechanism. Fig. 6 is a rear view of the first clamping mechanism. Fig. 7 is a side view of a press holding mechanism of the first clamping mechanism. Fig. 8 is a perspective view of a second clamping mechanism mounted on the sewing machine. Fig. 9 is a rear view of the second clamping mechanism. Fig. 10 is a front view of the first clamping mechanism equipped with release guides. Fig. 11 is an explanatory diagram showing a problem with an intermediate press. Fig. 12 is an explanatory diagram showing a projection portion provided on the intermediate pusher for solving the problem. Detailed description[Sewing machine overall configuration]

[0016] In the following, a sewing machine 100 according to an embodiment of the invention will be described with reference to the Fig. 1 to 9. The sewing machine 100 is an automatic sewing machine that uses first and second clamping mechanisms 30 and 50 adapted to hold a workpiece having a curved surface to perform stitch formation in any position according to a predetermined sewing pattern.

[0017] Fig. 1 and Fig. 2 are perspective views of the sewing machine 100 in which parts of a configuration are not shown, and Fig. 3 is a block diagram showing a control system of the sewing machine.

[0018] In the following description, a case is shown as an example in which a stiffening part C2 and a label C3 are used as a workpiece with respect to a heel portion of an annular upper part C1 (see Fig. 5) of a shoe can be sewn as one workpiece.

[0019] The sewing machine 100 includes a needle bar holding a stitch-forming needle at a lower end thereof, a needle bar vertical movement mechanism that moves the needle bar vertically, a shuttle mechanism that catches an upper thread passed through the stitch-forming needle to intertwine it with a lower thread, an intermediate presser mechanism that imparts vertical movement to the intermediate presser 11, the first clamping mechanism 30 that holds the upper part C1 and the stiffening part C2, the second clamping mechanism 50 that holds the upper part C1 and the label C3, an oscillation mechanism 70 that oscillates the first and second clamping mechanisms 30 and 50, a wave-line movement mechanism 80 that moves the first and second clamping mechanisms 30 and 50 along oscillation wave lines, a sewing machine frame 20,on which each of the above-described components is housed or mounted, and a controller 90 which controls each of the above-described components to perform stitch formation in any position on the upper part C1, the stiffening part C2 and the label C3.

[0020] The sewing machine frame 20 includes a bed portion 21 disposed below, an upright portion 22 rising from the bed portion 21, and an arm portion 23 extending parallel to the bed portion 21 from an upper end of the upright portion 22.

[0021] In Fig. 1 and Fig. 2, a cover of each portion of the sewing machine frame 20 is not shown; also not shown is an internal configuration of each portion.

[0022] The needle bar vertical movement mechanism has a known configuration including a sewing machine motor 12, a top shaft rotated by the sewing machine motor 12, and a crank mechanism that converts a rotational force of the top shaft into a driving force for vertical movement to transmit the force to the needle bar; therefore, a detailed description thereof will be omitted.

[0023] The shuttle mechanism has a known configuration including a so-called horizontal shuttle, a shuttle shaft that supports the horizontal shuttle, a sub-shaft that is rotated by the sewing machine motor 12, and a transmission mechanism that transmits a rotational force from the sub-shaft to the shuttle shaft; therefore, a detailed description thereof will be omitted.

[0024] The sewing machine 100 is a so-called post bed sewing machine, and the horizontal shuttle is installed in the upper part of a post bed 24 which is constructed at a position below the stitch forming needle in the bed portion 21.

[0025] The intermediate presser mechanism has a known configuration including an intermediate presser rod provided at a lower end thereof for supporting the intermediate presser 11, and a crank mechanism that converts a rotational force of the upper shaft into a driving force for vertical movement to transmit the force to the intermediate presser rod; therefore, a detailed description thereof will be omitted.

[0026] The intermediate presser 11 is provided with a cylindrical portion into which the stitch forming needle is loosely inserted, and a function of the cylindrical portion is to suppress fluttering of the workpiece by pressing the workpiece from above at the time of lifting the stitch forming needle.

[0027] The intermediate presser mechanism performs an operation transfer to vertically move the intermediate presser 11 later than the stitch-forming needle at the same cycle as the stitch-forming needle. Thus, the workpiece pulled by the lifting of the stitch-forming needle is pressed, and the stitch-forming needle is satisfactorily withdrawn from the workpiece. [First clamping mechanism]

[0028] Fig. 4 to 6 show a perspective view, a front view and a rear view of the first clamping mechanism 30, respectively.

[0029] The first clamping mechanism 30 includes four clamping units 40A to 40D arranged side by side in this order along the Y-axis direction to clamp the upper part C1 and the stiffening part C2 overlapping each other, and a frame 31 holding each of the clamping units 40A to 40D.

[0030] The four clamping units 40A to 40D have substantially the same configuration and structure. In the following description, the clamping units 40A to 40D are collectively referred to as clamping unit 40, wherein identical components of the clamping units 40A to 40D are described together using the same reference numerals, and different components of the clamping units 40A to 40D are described individually.

[0031] The frame 31 of the first clamping mechanism 30 is a long, flat plate. In this description, a Y-axis direction is parallel to the flat plate surface of the frame 31 and is defined as a direction parallel to a longitudinal direction of the frame; a Z-axis direction is parallel to the flat plate surface of the frame 31 and is defined as a direction orthogonal to the longitudinal direction of the frame; and an X-axis direction is defined as a direction vertical to the flat plate surface of the frame 31. In this way, each portion of the first clamping mechanism 30 is described.

[0032] The clamping unit 40 comprises a pair of clamping members formed by an upper clamping member 41 arranged above the upper part C1 and the stiffening part C2, and a lower clamping member 42 arranged below the upper part C1 and the stiffening part C2, a pressing holding mechanism 43 which presses the upper clamping member 41 to the lower clamping member 42, and a holding block 44 which holds the upper clamping member 41 and the lower clamping member 42.

[0033] The lower clamping member 42 is a plate-like member extending in the X-axis direction and extends away from the holding block 44 toward an opposite side of the frame 31.

[0034] Of the four clamp units 40A to 40D, each of the two clamp units 40B and 40C arranged centrally in the Y-axis direction has the lower clamp member 42 in which an upper surface is formed by two flat surfaces 421 and 422 (clamping surface) parallel to the X-axis direction, and each of the two clamp units 40A and 40D arranged at the two ends in the Y-axis direction has the lower clamp member 42 in which an upper surface is formed by a single flat surface 421 (clamping surface) parallel to the X-axis direction.

[0035] The lower clamping members 42 of these clamping units 40A to 40D are, as shown in Fig. 5, the flat surfaces 421 and 422 serving as the upper surface are arranged side by side along an upwardly projecting circular arc as viewed in the X-axis direction.

[0036] The lower clamping members 42 are each fitted to the holding block 44 by means of a screw 441 in a state in which an upper end surface thereof on the holding block 44 comes into contact with the lower surface of the holding block 44.

[0037] Each of the support blocks 44 has a stepped portion that contacts a side end of the lower clamp member 42 in the Y-axis direction. The support block 44 is formed with an elongated hole 442 penetrating vertically in the X-axis direction, and the screw 441 is inserted from above through the elongated hole 442 and thus into a screw hole of the lower clamp member 42.

[0038] Thereby, an extension length of the lower clamp member 42 relative to the holding block 44 can be adjusted to an arbitrary position by tightening the screw 441 after the lower clamp member 42 has been moved along the X-axis direction, while a slidable contact with the lower surface and the stepped portion of the holding block 44 can be established by loosening the screw 441.

[0039] Each of the lower clamping members 42 has an extension end that resembles a side edge of the stiffening member C2 as viewed in the Z-axis direction. Accordingly, it is possible to maintain the proximity of the stitching point position along the side edge of the stiffening member C2 at the time of sewing.

[0040] The upper clamp member 41 is a plate-like member and is held by the holding block 44 through the pressing holding mechanism 43 in a state where the lower surface of the upper clamp member is opposed to the upper surface of the lower clamp member 42.

[0041] Of the four clamp units 40A to 40D, each of the two clamp units 40B and 40C arranged centrally in the Y-axis direction has the upper clamp member 41 in which a lower surface is formed by two flat surfaces 411 and 412 (clamping surface) parallel to the X-axis direction, and each of the two clamp units 40A and 40D arranged at the two ends in the Y-axis direction has the upper clamp member 41 in which a lower surface is formed by a single flat surface 411 (clamping surface) parallel to the X-axis direction.

[0042] The upper clamping members 41 of these clamping units 40A to 40D are, as shown in Fig. 5, the flat surfaces 411 and 412 serving as the lower surface are arranged side by side along an upwardly projecting circular arc as viewed in the X-axis direction.

[0043] In the upper clamp members 41 of the clamp units 40A to 40D, each of the flat surfaces 411 and 412 serving as the lower surface is individually arranged parallel to each of the flat surfaces 421 and 422 serving as the upper surface of the lower clamp members 42 opposite the upper clamp members 41. Thus, the top part C1 and the stiffening part C2 can be held in a state of being sandwiched between the respective upper clamp member 41 and the respective lower clamp member 42 substantially along a circumferential surface comprising the circular arc described above.

[0044] Fig. 7 is a side view of the clamping unit 40.

[0045] The pressure holding mechanism 43 includes a movable block 431 which is fitted to the upper surface of the upper clamp member 41 by means of a screw, a base 432 which is fixed to the upper surface of the holding block 44, an operating lever 433 which, via a rotational operation, switches the upper clamp member 41 to a holding position in which the upper clamp member 41 is opposed to the lower clamp member 42 and to a release position which is spaced from the lower clamp member 42, a rotating arm 434 which holds the upper clamp member 41 through the movable block 431, and a connecting link 435 which couples the base 432 and the operating lever 433 to each other.

[0046] One end of the base 432 in the X-axis direction is rotatably coupled to a lower part of one end of the rotary arm 434 about the Y-axis, and the other end of the base 432 in the X-axis direction is rotatably coupled to one end of the link 435 about the Y-axis.

[0047] One end of the operating lever 433 is coupled to an upper part of one end of the rotary arm 434 for rotation about the Y axis, while the other end thereof becomes an input operation unit for switching between the holding position and the release position. Furthermore, the other end of the connecting link 435 is coupled for rotation about the Y axis at a position near one end of the operating lever 433 and slightly near the other end thereof.

[0048] In this way, the base 432, the operating lever 433, the rotating arm 434 and the connecting link 435 form a four-bar linkage mechanism.

[0049] With this configuration, when the input operation unit of the operation lever 433 rotates downward, the coupling point between the operation lever 433 and the link 435 is positioned lower than a straight line connecting the coupling point between the operation lever 433 and the rotation arm 434 and the coupling point between the link 435 and the base 432. Even if the upper part C1 and the stiffening part C2 are clamped between the upper clamp member 41 and the lower clamp member 42 in such a state and thus the operation lever 433 is pressed back by a restoring force, it is possible to maintain the clamped state without transmitting the force in a direction in which the input operation unit of the operation lever 433 is pushed upward.

[0050] The rotating arm 434 is formed with a slotted hole 434b penetrating vertically along the X-axis direction and is coupled to the movable block 431 via a screw 434a threaded through the slotted hole 434b. Accordingly, the movable block 431 can move to any position in the X-axis direction in a state where the screw 434a is loosened, while it can be fixed at a position where the screw 434a is tightened.

[0051] That is, the position of the upper clamping member 41 can be arbitrarily adjusted in the X-axis direction. As described above, since the lower clamping member 42 can also be arbitrarily adjusted in the X-axis direction, the position of the upper clamping member 41 and the lower clamping member 42 can be adjusted, and thus, it is possible to adjust a clamping width between the upper clamping member 41 and the lower clamping member 42.

[0052] As described above, the holding block 44 holds the upper clamping member 41 at its upper surface and the lower clamping member 42 at its lower surface.

[0053] The holding block 44 has an end surface which comes into contact with a flat plate surface of the frame 31 at an opposite end of an extension end of the upper clamp member 41 and the lower clamp member 42, and is held by the frame 31 in a state in which the end surface comes into close contact with the frame 31.

[0054] As in Fig. 6, the frame 31 is a flat plate which is long in the Y-axis direction and has a substantially arc-shaped configuration.

[0055] The frame 31 is formed with upper fitting holes 32 and 33 and lower fitting holes 34 and 35, which are elongated holes having a polygonal line shape with a plurality of straight lines along a circular arc as a curved line and penetrating the frame 31 side by side in a vertical direction, and is thereby fitted with four clamp units 40A to 40D.

[0056] The upper fitting holes 32 and 33 are formed at one end and the other end of the frame 31 in the Y-axis direction, respectively, and both have two straight portions 321 and 322 and 331 and 332, respectively.

[0057] These rectilinear regions 321, 322, 331 and 332 are all formed along a common circular arc A1, in which a center position is set below the frame 31.

[0058] The lower fitting holes 34 and 35 are formed at one end and the other end of the frame 31 in the Y-axis direction, respectively, and both have two straight portions 341 and 342 and 351 and 352, respectively.

[0059] These rectilinear portions 341, 342, 351, and 352 are all formed along a common circular arc A2 having a center position set below the frame 31. The circular arc A2 is concentric with the circular arc A1 described above and is set with a smaller diameter than the circular arc A1.

[0060] The upper fitting holes 32 and 33 are divided into two parts; however, they can also be coupled together to form a single upper fitting hole. In this case, more straight sections can be formed. This also applies to the lower fitting holes 34 and 35.

[0061] The holding block 44 of each of the clamping units 40A to 40D is fixed to the frame 31 by tightening screws 36 and 37 (see Fig. 7) which are individually inserted into the upper fitting hole 32 or the upper fitting hole 33 and the lower fitting hole 34 or the lower fitting hole 35 through two screw holes formed side by side in the vertical direction on the end surface of the frame 31.

[0062] Furthermore, the position of each of the clamping units 40 can be adjusted along the upper fitting hole 32 and the lower fitting hole 34, or along the upper fitting hole 33 and the lower fitting hole 35, by loosening these screws 36 and 37. That is, the position of each of the clamping units 40 can be adjusted substantially along the circular arcs A1 and A2. It is possible to adjust the position while maintaining a constant position with respect to the centers of the two circular arcs A1 and A2.

[0063] It is possible to fit the holding block 44 with only one of the fitting holes, which are the upper fitting hole and the lower fitting hole, in a uniaxial direction, and adjust its angle around the uniaxial direction. In this case, each of the clamping units 40 is no longer held at a constant position relative to the centers of the two circular arcs A1 and A2; however, the workpiece can be bent into various shapes independently of the circular arc. [Second clamping mechanism]

[0064] Fig. 8 and Fig. 9 show a perspective view and a rear view of a second clamping mechanism 50.

[0065] With regard to the second clamping mechanism 50, the same reference numerals are used for a configuration or structure identical to that of the first clamping mechanism 30 described above, and duplicate descriptions are omitted. Here, the main points of distinction from the first clamping mechanism 30 will be described.

[0066] The second clamping mechanism 50 includes three clamping units 60A to 60C arranged side by side in this order along a Y-axis direction to clamp a top C1 and a label C3, and a frame 51 holding each of the clamping units 60A to 60C.

[0067] The three clamping units 60A to 60C are collectively referred to as clamping unit 60, with identical components of the clamping units 60A to 60C being described using the same reference numerals, and different components of the clamping units 60A to 60C being described individually. Here, the main points of distinction from the first clamping mechanism 30 are described.

[0068] In this description, a Y-axis direction is parallel to the flat plate surface of the frame 51 and is defined as a direction parallel to a longitudinal direction of the frame; a Z-axis direction is parallel to the flat plate surface of the frame 51 and is defined as a direction orthogonal to the longitudinal direction of the frame; and an X-axis direction is defined as a direction vertical to the flat plate surface of the frame 51; the second clamping mechanism 50 is also described in this manner.

[0069] The clamping unit 60 comprises a pair of clamping members formed by an upper clamping member 61 arranged above the upper part C1 and the label C3, and a lower clamping member 62 arranged below the upper part C1 and the label C3, a pressing holding mechanism 43 which presses the upper clamping member 61 against the lower clamping member 62, and a holding block 64 which holds the upper clamping member 61 and the lower clamping member 62.

[0070] The lower clamping member 62 is a plate-like member and extends away from the support block 64 toward an opposite side of the frame 51.

[0071] Of the three clamp units 60A to 60C, only the clamp unit 60B, which is arranged centrally in the Y-axis direction, has a lower clamp member 62 having a pair of lower clamp members 621 and 622 arranged along the Y-axis direction.

[0072] The lower clamping members 62, 621 and 622 of the clamping units 60A to 60C all have an upper surface formed by a single flat surface (clamping surface) parallel to the X-axis direction.

[0073] In the lower clamp members 62, 621 and 622 of these clamp units 60A to 60C, each of the flat surfaces serving as the upper surface is arranged side by side along an upwardly projecting circular arc as viewed in the X-axis direction.

[0074] Similar to the first clamping mechanism 30, each of the two clamping units 60A and 60C has the lower clamping member 62 held by the holding block 64 such that its position can be adjusted in the X-axis direction.

[0075] On the other hand, with respect to the middle clamp unit 60B, the pair of lower clamp members 621 and 622 are held by the holding block 64 such that their positions can be individually adjusted along the Y-axis direction.

[0076] In each of the lower clamping members 62 of all the clamping units 60A to 60C, an extension end has a shape similar to that of a side edge of the label C3.

[0077] The upper clamp member 61 is a plate-like member and is held by the holding block 64 through the pressing holding mechanism 43 in a state in which the lower surface of the upper clamp member faces the upper surface of the lower clamp member 62.

[0078] Only the center clamp unit 60B has the upper clamp member 61, which includes a pair of upper clamp members 611 and 612 arranged along the Y-axis direction.

[0079] All upper clamping members 61, 611 and 612 of the clamping unit 60 have a lower surface formed by a single flat surface (clamping surface) parallel to the X-axis direction.

[0080] In the upper clamp members 61, 611 and 612 of these clamp units 60A to 60C, the flat surfaces serving as the lower surface are each arranged side by side along an upwardly projecting circular arc as viewed in the X-axis direction.

[0081] Similar to the first clamping mechanism 30, the lower surfaces (clamping surfaces) of the upper clamping members 61, 611 and 612 are arranged parallel to the opposite upper surfaces of the lower clamping members 62, 621 and 622, respectively.

[0082] Since each of the clamping units 60 has the pressure holding mechanism 43 which is similar to that of the first clamping mechanism 30, a description thereof will be omitted.

[0083] However, the two clamp units 60A and 60C are configured such that the upper clamp member 61 is held by the pressing holding mechanism 43 to be positionally adjustable in the X-axis direction, while the middle clamp unit 60B is configured such that the pair of upper clamp members 611 and 612 are held by the pressing holding mechanism 43 to be positionally adjustable in the Y-axis direction.

[0084] As in Fig. 9, the frame 51 is a flat plate which is long in the Y-axis direction and is formed in a substantially arc shape.

[0085] The frame 51 is formed with upper fitting holes 52 and 53 and lower fitting holes 54 and 55, which are elongated holes having a plurality of straight lines along a circular arc as a curved line and which penetrate the frame 51 side by side in a vertical direction, thereby fitting it with three clamp units 60A to 60C.

[0086] The upper fitting holes 52 and 53 are each formed near the center of the frame 51 in the Y-axis direction; both are formed along a common circular arc A3 in which a center position is set below the frame 51.

[0087] The lower fitting holes 54 and 55 are each formed near the center of the frame 51 in the Y-axis direction, and both are formed along a common circular arc A4 having a center position set below the frame 51. The circular arc A4 is concentric with the circular arc A3 described above and has a smaller diameter than the circular arc A3.

[0088] The upper fitting holes 52 and 53 are divided into two parts; however, they can also be coupled together to form a single upper fitting hole. In this case, a polygonal line shape with a plurality of straight lines can be formed. This also applies to the lower fitting holes 54 and 55.

[0089] The holding block 64 of the clamp unit 60A is fixed to the frame 51 by fastening the end surface of the frame 51 by means of two screws 56 (one of the screws is not shown) which are individually inserted into the upper fitting hole 52 and the lower fitting hole 54.

[0090] The holding block 64 of the clamp unit 60C is fixed to the frame 51 by fastening the end surface of the frame 51 by means of two screws 56 (one of the screws is not shown) which are individually inserted into the upper fitting hole 53 and the lower fitting hole 55.

[0091] Similar to the first clamping mechanism 30, the position of these two clamping units 60A and 60C can be adjusted along the upper fitting hole 52 and the lower fitting hole 54 or along the upper fitting hole 53 and the lower fitting hole 55, whereby it is possible to adjust the position while maintaining a constant posture. [Wavy line movement mechanism]

[0092] The wave-line motion mechanism 80 includes a table 81 on which the oscillation mechanism 70 and the first and second clamping mechanisms 30 and 50 are mounted, a pair of slide guides 82 and 82 that hold the table 81 movable along a direction of an oscillation wave line of the oscillation mechanism 70, a wave-line motion motor 83 that serves as a drive source for moving the table 81 in the direction of the oscillation wave line, and a ball screw mechanism 84 that converts a torque of the wave-line motion motor 83 into a linear motion in the direction of the oscillation wave line.

[0093] The slide guides 82 and 82 are fixedly mounted on the upper surface of the bed portion 21 to run parallel to the direction of the oscillation wave line. The direction of the oscillation wave line coincides with a longitudinal direction of the bed portion 21 and the arm portion 23.

[0094] Each of the sliding guides 82 and 82 is designed such that the table 81 is supported by four sliding elements 821 (only one of which is in Fig. 1 and Fig. 2) provided in a lower part of the table 81.

[0095] Table 81 is a rectangular frame body.

[0096] The ball screw mechanism 84 includes a ball nut 841 provided at a corner of the table 81, and a ball screw shaft 842 coupled to an output shaft of the shaft line motion motor 83 while passing through the ball nut 841.

[0097] There are no particular restrictions on the wave-line motion motor 83, as long as it is a motor capable of controlling an operation amount. For example, a stepper motor is used.

[0098] In these configurations, the wave line moving mechanism 80 can arbitrarily adjust the position of the top part C1, the stiffening part C2 and the label C3, which are held on the table 81 by means of the first and second clamping mechanisms 30 and 50, in the direction of the oscillation wave line. [Oscillation mechanism]

[0099] The oscillation mechanism 70 includes an oscillation frame body 71 provided to be oscillatable relative to the table 81 of the wave line movement mechanism 80 about a predetermined oscillation shaft, an oscillation guide 72 that guides the oscillation of the oscillation frame body 71, an oscillation motor 73 mounted on the upper surface of the table 81 and serving as a drive source for an oscillation operation of the oscillation frame body 71, and a transmission mechanism 74 that transmits a torque of the oscillation motor 73 to the oscillation frame body 71.

[0100] The first clamping mechanism 30 and the second clamping mechanism 50 are fixedly held by the oscillating frame body 71 such that the extending directions of the pair of clamping members are parallel to each other or face each other. For example, the first clamping mechanism 30 and the second clamping mechanism 50 are coupled to each other in advance in a facing state, and these clamping mechanisms 30 and 50 are fixedly held by a toggle mechanism 711 provided in the oscillating frame body 71.

[0101] Further, the oscillation frame body 71 is pivotally supported via an oscillation shaft (not shown) provided below the table 81.

[0102] The oscillation frame body 71 is set such that all the centers, which are the center of the circular arc along which the lower surface of the upper clamping member and the upper surface of the lower clamping member of the first and second clamping mechanisms 30 and 50 to be fixedly held are formed, the center of the circular arcs A1 and A3 of the upper fitting hole, and the center of the circular arcs A2 and A4 of the lower fitting hole, are positioned on the shaft line of the oscillation shaft.

[0103] Thus, even when the oscillating frame body 71 oscillates, the distance between the stitch forming needle or the horizontal shuttle and the upper part C1, the stiffening part C2 and the label C3, which are held by the first clamping mechanism 30 and the second clamping mechanism 50, can be kept constant.

[0104] The oscillation guide 72 is a guide plate having a guide groove into which a boss-like projection (not shown) is inserted. The boss-like projection is provided on the oscillation frame body 71. The guide groove is formed in a circular arc shape and has the oscillation wave line as its center to maintain a stable oscillation operation by suppressing vibrations at the time of oscillation of the oscillation frame body 71.

[0105] There are no particular restrictions on the oscillation motor 73, as long as it is a motor capable of controlling an operation amount. For example, a stepper motor is used.

[0106] The transmission mechanism 74 is constructed of a so-called belt mechanism. Specifically, the transmission mechanism 74 includes a drive gear 741 provided on the output shaft of the oscillation motor 73, a driven gear (not shown) provided on the oscillation shaft of the oscillation frame body 71, and a timing belt 742 stretched between the drive gear 741 and the driven gear.

[0107] With these configurations, the oscillation mechanism 70 can arbitrarily control an oscillation angle of the top part C1, the stiffening part C2 and the label C3, which are held by the first and second clamping mechanisms 30 and 50 on the table 81. [Sewing machine control system]

[0108] As in Fig. 3, the controller 90 is connected via an input / output circuit (not shown) to: a display panel 94 which displays various set values ​​related to sewing or a state of the present sewing machine; a set switch 95 which is located beside the display panel 94 and serves as a set input unit used to perform a screen selection or a command for executing various set values ​​and inputting numerical values; and an operation pedal 98 for inputting the sewing start.

[0109] The operation pedal 98 is used to input a sewing operation drive command to the controller 90 via a treadle operation. That is, when the treadle operation is performed on the operation pedal 98, the controller 90 executes an operation control to start sewing.

[0110] Using the setting switch 95, the worker enters various parameters for sewing the stiffening part C2 and the label C3 to the upper part C1. For example, the worker sets sewing pattern data for sewing or selects sewing pattern data using the setting switch 95.

[0111] The controller 90 is connected to the motors to be controlled, which are the sewing machine motor 12, the oscillation motor 73 and the wave line movement motor 83, via drive circuits 12a, 73a and 83a.

[0112] The controller 90 includes a CPU 91 which executes various types of controls, and a memory 92 in which a control program for executing the operation control of the sewing machine 100 and various sewing data are written.

[0113] For example, 92 sewing pattern data are stored in the memory.

[0114] The sewing pattern data includes position coordinate data in which all stitch point positions constituting the sewing pattern for sewing the stiffener part C2 and the label C3 are developed in a coordinate system, including a direction position of the oscillation wave line and an oscillation angle.

[0115] The sewing pattern data are determined depending on the shoe size of the upper C1 and the sizes of the left and right shoes, and it is possible to select appropriately from these sewing pattern data.

[0116] According to a control program, the CPU 91 reads the selected sewing pattern data, calculates an operation amount of the oscillation motor 73 and the wavy line movement motor 83 per stitch to perform positioning of the upper part C1, the stiffening part C2, and the label C3, respectively, at the stitch point positions constituting the sewing pattern, and, based on the calculated operation amount, controls the driving of the oscillation motor 73 and the wavy line movement motor 83 per stitch in synchronization with the sewing machine motor 12. [Preparation for sewing and sewing operation]

[0117] The procedure is now described, starting from the preparatory work for sewing the stiffening part C2 and the label C3 with respect to the upper part C1 up to the execution of the sewing work on the sewing machine 100.

[0118] First, one end of the upper part C1 or the stiffening part C2 is placed on the first clamping mechanism 30 and the other end of the upper part C1 or the label C3 is placed on the second clamping mechanism 50.

[0119] That is, the operating lever 433 is pushed upward with respect to all the clamping units 40A to 40D of the first clamping mechanism 30 to cause the upper clamping member 41 to assume a release state. The upper part C1 and the stiffening part C2 are superimposed on each other and, after positioning for sewing, placed on the lower clamping member 42; then, they are clamped by the upper clamping member 41 and the lower clamping member 42 by depressing the operating lever 433.

[0120] Also, with respect to the clamping units 60A to 60C of the second clamping mechanism 50, the upper part C1 and the label C3 are clamped in the same manner.

[0121] The first clamping mechanism 30 and the second clamping mechanism 50 are installed in the oscillation frame body 71 of the oscillation mechanism 70 via the toggle mechanism 711.

[0122] After completion of the preparatory work, when the sewing pattern data is selected via the set switch 95 of the sewing machine 100, the CPU 91 calculates the operation amount of the oscillation motor 73 and the wave line movement motor 83 per stitch.

[0123] When the sewing start is input via the operation pedal 98, the CPU 91 starts the drive of the sewing machine motor 12, drives the oscillation motor 73 and the wavy line movement motor 83 based on the calculated operation amount in synchronization with the vertical movement of the needle bar per stitch, oscillates and moves the head C1, the stiffener C2 and the label C3 along the wavy line and sequentially executes stitch formation at stitch point positions specified in the sewing pattern data.

[0124] When the stitch formation has been completed at all stitch point positions specified in the sewing pattern data, the sewing machine motor 12 is stopped and the sewing operation is completed.

[0125] Further, the first clamping mechanism 30 and the second clamping mechanism 50 are released from the oscillating frame body 71, and the upper clamping member 41 is set to a release state with respect to all the clamping units 40A to 40D of the first clamping mechanism 30. Similarly, all the clamping units 60A to 60C of the second clamping mechanism 50 are set to the release state.

[0126] This allows the upper part C1 sewn with the stiffening part C2 and the label C3 to be removed, and a series of sewing operations is completed. [Effects of the embodiment]

[0127] In the first clamping mechanism 30 of the sewing machine 100, as described above, the frame 31 has the elongated fitting holes 32 to 35 formed along a plurality of straight lines aligned to follow the circular arc, and four clamping units 40A to 40D are positionally adjustable fitted along the fitting holes 32 to 35 of the frame 31.

[0128] Also in the second clamping mechanism 50, the frame 51 has the elongated fitting holes 52 to 55 formed along a plurality of straight lines aligned to follow the circular arc, and three clamping units 60A to 60C are positionally adjustable fitted along the fitting holes 52 to 55 of the frame 51.

[0129] This makes it possible to arrange each of the clamping units depending on curved surfaces of different sizes to hold the workpiece along the curved surface, eliminating the need for an individual holding body corresponding to each size. In particular, although the size of the workpiece is finely divided in shoe sewing, the workpiece can also be held depending on different sizes by adjusting the position of the clamping unit in the first or second clamping mechanism 30 or 50, respectively, which is particularly effective.

[0130] Because the first or second clamping mechanism 30 or 50 is configured such that the lower surface of the upper clamping member 41 or 61 and the upper surface of the lower clamping member 42 or 62 of the clamping unit 40 or 60 are formed by one or two flat surfaces, each of the clamping members can be easily manufactured. In particular, when configured with two or more flat surfaces, it can hold the workpiece in a state closer to the curved surface, and excellent sewing can be performed on the workpiece with the curved surface.

[0131] In the first and second clamping mechanisms 30 and 50, respectively, the upper clamping member 41 and 61 and the lower clamping member 42 and 62 are configured to adjust the position along the extending direction.

[0132] Accordingly, it is possible to arbitrarily adjust the extension amount of the clamping member 41, 42, 61, or 62, and to adjust the clamping width based on the upper clamping member 41 or 61 and the lower clamping member 42 or 62. It is thus possible to achieve excellent clamping of various workpieces with different dimensions.

[0133] Around the wave line located at all centers, which are the center of the circular arc A1 along the upper fitting holes 32 and 33 and the center of the circular arc A2 along the lower fitting holes 34 and 35 of the frame 31 of the first clamping mechanism 30 as well as the center of the circular arc A3 along the upper fitting holes 52 and 53 and the center of the circular arc A4 along the lower fitting holes 54 and 55 of the frame 51 of the second clamping mechanism 50, the sewing machine 100 comprises the oscillation mechanism 70 which oscillates the first and second clamping mechanisms 30 and 50, the wave line moving mechanism 80 which moves the first and second clamping mechanisms 30 and 50 along the wave line around which the first and second clamping mechanisms 30 and 50 are oscillated, and the controller 90 which controls these mechanisms to perform the stitch formation at any position of the workpiece.

[0134] Accordingly, by combining oscillation and linear motion, it is possible to perform stitch formation on the curved surface of the workpiece with more accuracy and achieve an improvement in sewing quality.

[0135] In the sewing machine 100, when the stitch point positions are sequentially stored via the sewing pattern data or the like, it is possible to perform automatic sewing according to the sewing pattern on the curved surface.

[0136] Since the sewing machine 100 includes the intermediate presser 11 which performs a vertical movement in conjunction with the needle bar, after stitch formation is completed, the stitch forming needle can be more reliably withdrawn from the workpiece moved and oscillated along the oscillation wave line; damage to the workpiece or the stitch forming needle can be prevented, and the workpiece can be moved excellently. [Release Guide]

[0137] When the upper part C1 as a workpiece has a toe part C11 as a vertical extension portion which is to assume a vertical extension state when set in the first clamping mechanism 30, the column bed 24 is provided as a stitching point position immediately below the upper part C1, and the toe part C11 may interfere.

[0138] Accordingly, as in Fig. 10, the frame 31 of the first clamping mechanism 30 may be formed with a pair of release guides 38 and 39 which guide the toe part C11 toward a direction of the oscillation wave line (toward the frame 31 in this example).

[0139] In order to prevent the disturbing effect on the column bed 24 at the time of oscillation of the clamping mechanism 30, the release guides 38 and 39 are arranged such that the guides are guided entirely toward the frame 31 rather than toward the end surface of the column bed 24 on the frame 31 in the direction of the oscillation wave line after the first clamping mechanism 30 has been moved to the side opposite to the frame 31 in the direction of the oscillation wave line.

[0140] In this way, it is possible to reduce the occurrence of interference between the toe part C11 and the column bed 24 at the time of sewing and to perform excellent sewing.

[0141] The release guides 38 and 39 are designed to move the toe part C11 toward the frame; however, they may also be designed to move the toe part C11 toward the opposite side in the direction of the oscillation wave line.

[0142] Furthermore, the release guides 38 and 39 are rod-shaped; however, they can also be plate-shaped. Two release guides 38 and 39 are provided as an example; however, it is also possible to provide only a single release guide or at least three release guides.

[0143] The release guides 38 and 39 may be formed in the second clamping mechanism 50 without being limited to the first clamping mechanism 30. [Protrusion area]

[0144] As in Fig.11, a shuttle 14 is installed in an inner upper part of the column bed 24, and at an upper end of the column bed 24, a needle plate 15 is provided which is formed with needle holes (not shown) at which stitch formation is carried out by means of the stitch formation needle 13.

[0145] Since the stiffening part C2 or the label C3, which constitutes the workpiece, is held along the curved surface by means of the first and second clamping mechanisms 30 and 50, a gap is formed between the stiffening part C2 or the label C3 and the throat plate 15.

[0146] In this case, when the intermediate presser 11 descends, sewing is performed in a state where the stiffener C2 or the label C3 is bent downward to collapse the gap; as a result, sewing may not be performed excellently.

[0147] When the stiffening member C2 or the label C3 is brought as close as possible to the throat plate 15 to eliminate the gap, the throat plate 15 and the stiffening member C2 or the label C3 come into sliding contact with each other at the time of oscillation of the first and second clamping mechanisms 30 and 50 and may be deflected by the first and second clamping mechanisms 30 and 50, whereby the stiffening member C2 or the label C3 may be damaged.

[0148] Therefore, when using the intermediate presser 11, it is more desirable that an upwardly projecting protrusion portion 16 is formed around the stitching point position of the needle plate 15 and the sewing operation is performed by pressing the stiffening member C2 and the label C3 from above and below with the descending intermediate presser 11 and the protrusion portion 16.

[0149] By the thus provided protrusion portion 16, the stiffening member C2 and the label C3 can be prevented from being bent downward by the intermediate presser 11, and they can be excellently sewn while being kept in the state of being close to the curved surface, whereby more excellent sewing can be realized.

[0150] By means of the projection portion 16, it is possible to reduce the occurrence of sliding contact between the stiffening part C2 or the label C3 and the throat plate 15. [More]

[0151] In the first or second clamping mechanism 30 or 50, the upper fitting holes 32 and 33 or 52 and 53 and the lower fitting holes 34 and 35 or 54 and 55 formed in the frame 31 or 51 have one or two straight lines; however, they may also have more straight lines, and they may have the circular arc or curved lines other than the circular arc.

[0152] In particular, when the shape of the workpiece is a curved surface which is different from the curved surface with a circular arc-shaped cross section, the fitting holes are preferably each formed in the shape of a curved line which corresponds to the cross-sectional shape of the curved surface.

[0153] The position of the oscillation wave line based on the oscillation mechanism 70 is most preferably the center of the circular arc along which the fitting holes are respectively formed; however, it may also be close to the circular arc away from the center.

[0154] If the shape of the fitting hole is in the form of a recess instead of a circular arc, then the oscillation wave line may be arranged within the recess.

[0155] The lower surface of the upper clamping member and the upper surface of the lower clamping member can be formed into a single curved surface, without being limited to one or two flat surfaces. When these lower and upper surfaces are formed into a single curved surface, it is possible to hold the workpiece along the curved surface and perform more excellent sewing.

[0156] In the first clamping mechanism 30 and the second clamping mechanism 50, the number of clamping units may be at least two; however, it may also be larger or smaller.

[0157] The clamping elements are not limited to the plate shape. For example, the upper and lower clamping elements can be formed by a pair of bars. In this case, the number of clamping units increases, and it is therefore desirable to further increase the clamping positions by the bars.

[0158] In the above embodiment, although the case of performing sewing using both the first clamping mechanism 30 and the second clamping mechanism 50 is exemplified, only one of the two clamping mechanisms, namely the first clamping mechanism 30 and the second clamping mechanism 50, may be installed in the sewing machine 100, and sewing can be performed even then.

[0159] Although the wave line moving mechanism 80 moves each of the clamping mechanisms 30 and 50 in the direction of the wave line, the sewing machine 100 is not limited to this configuration and may be equipped with a mechanism that moves the needle bar in the direction of the wave line or with a needle oscillation mechanism that moves the lower end of the needle bar along the direction of the wave line.

Claims

[1] Clamping mechanism (30; 50) of a sewing machine (100), comprising: a plurality of clamping units (40A, 40B, 40C, 40D; 60A, 60B, 60C), each comprising: (i) a pair of clamping members (41, 42; 61, 62) which clamp a workpiece, and (ii) a holding block (64) which holds the pair of clamping members (41, 42; 61, 62); and a frame (31; 51) with which the holding blocks (64) are fitted, wherein the frame (31; 51) has at least one elongated fitting hole (32, 33, 34, 35; 52, 53, 54, 55) formed along a curved line or along a plurality of straight lines along the curved line, and wherein the plurality of clamping units (40A, 40B, 40C, 40D; 60A, 60B, 60C) are fitted in a positionally adjustable manner along the at least one fitting hole (32, 33, 34, 35; 52, 53, 54, 55) of the frame (31, 51). [2] A clamping mechanism according to claim 1, wherein the clamping member (41, 42; 61, 62) has a clamping surface (411, 412; 421, 422) comprising a single or a plurality of flat surfaces (411, 412; 421, 422). [3] A clamping mechanism according to claim 1, wherein the clamping member (41, 42; 61, 62) has a clamping surface (411, 412; 421, 422) having a single curved surface. [4] Clamping mechanism according to one of claims 1 to 3, wherein the pair of clamping members (41, 42; 61, 62) extends relative to the holding block (64) towards an opposite side of the frame (31; 51) and wherein the holding block (64) holds the pair of clamping members (41, 42; 61, 62) positionally adjustable along an extension direction of the pair of clamping members (41, 42; 61, 62). [5] Clamping mechanism according to one of claims 1 to 4, further comprising: a release guide (38, 39) which releases a vertical extension area from a stitch point position, wherein the vertical extension region extends vertically away from the workpiece clamped by the clamping members (41, 42; 61, 62). [6] Sewing machine (100), comprising: an oscillation mechanism (70) which oscillates the clamping mechanism (30, 50) according to one of claims 1 to 5 about a wave line; wherein the wavy line is arranged within a curved line of the at least one fitting hole (32, 33, 34, 35; 52, 53, 54, 55) of the frame (31, 51); a wave line movement mechanism (80) which moves the clamping mechanisms (30; 50) and a needle bar relative to each other along the wave line of the clamping mechanism (30, 50); and a controller (90) which controls a drive source of the oscillation mechanism (70) and a drive source of the wave line movement mechanism (80) to perform stitch formation at a position of the workpiece. [7] Sewing machine according to claim 6, further comprising: an intermediate presser (11) which moves vertically in conjunction with the needle bar. [8] Sewing machine according to claim 7, further comprising: a stitch plate (15) on which a stitch formation is carried out, wherein a projection portion (16) is provided at a stitch point position of the throat plate (15) to press the workpiece from above and from below in cooperation with the descending intermediate presser (11).

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