Differential feed sewing machine

Abstract

The differential feed sewing machine (1) includes a main feed dog (11) configured to feed a lower fabric (41), an auxiliary feed dog (12) configured to feed the lower fabric (41), an upper feed dog (13) configured to feed an upper fabric (42), and a controller (20). The controller (20) includes a sewing data obtaining unit (21) configured to obtain sewing data including a lower fabric length (Ld), which indicates a length of the lower fabric (41), an upper fabric length (Lt), which indicates a length of the upper fabric (42), and a finished length (Lm), which indicates a target value of a length of a sewn product (43) after the lower fabric (41) and the upper fabric (42) are sewn. The controller (20) also includes a calculation unit (23) configured to calculate a feed amount of the auxiliary feed dog (12) and a feed amount of the upper feed dog (13) relative to a feed amount of the main feed dog (11) based on the sewing data. The controller (20) also includes a control unit (24) configured to control respective feeding operations of the main feed dog (11), the auxiliary feed dog (12), and the upper feed dog (13) based on the feed amounts calculated by the calculation unit (23).

Description

TECHNICAL FIELD

[0001] The technology disclosed in the present specification relates to a differential feed sewing machine.BACKGROUND ART

[0002] In the technical field of sewing machines, a differential feed sewing machine as disclosed in JP2007-185296A is known.SUMMARY OF INVENTION

[0003] A differential feed sewing machine includes a main feed dog for feeding a lower fabric, an auxiliary feed dog for feeding the lower fabric, and an upper feed dog for feeding an upper fabric. By changing a feed amount of the auxiliary feed dog and a feed amount of the upper feed dog relative to a feed amount of the main feed dog, clothes of various designs are produced.

[0004] When sewing the upper and lower fabrics using the differential feed sewing machine, if the feed amount of the auxiliary feed dog and the feed amount of the upper feed dog relative to the feed amount of the main feed dog are not set appropriately, it becomes difficult to produce clothes with the desired design. In the related art, operators of differential feed sewing machines adjust the feed amounts through trial and error to ensure that clothes with the desired design can be manufactured.

[0005] The technology disclosed in the present specification is to easily set feed amounts in a differential feed sewing machine.

[0006] The present specification discloses a differential feed sewing machine. The differential feed sewing machine includes a main feed dog configured to feed a lower fabric, an auxiliary feed dog configured to feed the lower fabric, an upper feed dog configured to feed an upper fabric, and a controller. The controller includes a sewing data obtaining unit configured to obtain sewing data including a lower fabric length, which indicates a length of the lower fabric, an upper fabric length, which indicates a length of the upper fabric, and a finished length, which indicates a target value of a length of a sewn product after the lower fabric and the upper fabric are sewn. The controller also includes a calculation unit configured to calculate a feed amount of the auxiliary feed dog and a feed amount of the upper feed dog relative to a feed amount of the main feed dog based on the sewing data. The controller also includes a control unit configured to control respective feeding operations of the main feed dog, the auxiliary feed dog, and the upper feed dog based on the feed amounts calculated by the calculation unit.

[0007] According to the technology disclosed in the present specification, feed amounts in a differential feed sewing machine can be easily set.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a perspective view showing a sewing machine according to an embodiment. FIG. 2 is a schematic diagram showing the sewing machine according to an embodiment. FIG. 3 is a block diagram showing the sewing machine according to an embodiment. FIG. 4 is a schematic diagram showing a needle plate, a presser, a main feed dog, an auxiliary feed dog, and an upper feed dog according to an embodiment. FIG. 5 is a diagram for describing a relationship among a main feed amount, an auxiliary feed amount, an upper feed amount, and a sewn product in an embodiment. FIG. 6 is a diagram for describing the relationship between the main feed amount, the auxiliary feed amount, the upper feed amount, and the sewn product in an embodiment. FIG. 7 is a hardware configuration diagram showing a controller according to an embodiment. FIG. 8 is a functional block diagram showing a controller according to an embodiment. FIG. 9 is a diagram for describing sewing data according to an embodiment. FIG. 10 is a diagram for describing a relationship between an actual sewn product length and a finished length according to an embodiment. FIG. 11 is a diagram showing an operation panel according to an embodiment. FIG. 12 is a flow chart showing a sewing method according to an embodiment. FIG. 13 is a schematic diagram showing sewing data according to an embodiment. DESCRIPTION OF EMBODIMENTS

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the embodiments, the positional relationship of each part will be described using the terms such as left, right, front, rear, up, and down. These terms indicate relative positions or directions with respect to a center of a sewing machine 1.[Sewing Machine]

[0010] FIG. 1 is a perspective view showing a sewing machine 1 according to an embodiment. FIG. 2 is a schematic diagram showing the sewing machine 1 according to an embodiment. FIG. 3 is a block diagram showing the sewing machine 1 according to an embodiment. In the embodiment, the sewing machine 1 is an industrial sewing machine. The sewing machine 1 is a differential feed sewing machine. The sewing machine 1 is installed in a sewing factory.

[0011] The sewing machine 1 includes a sewing machine frame 3, a needle bar 5, a thread take-up lever 6, a needle plate 7, a presser 8, a thread tensioner 9, a shuttle 10, a main feed dog 11, an auxiliary feed dog 12, an upper feed dog 13, a sewing machine motor 14, an adjustment motor 15, a sewing machine power transmission mechanism 16, a feed amount adjustment mechanism 17, a pedal 18, an operation panel 19, and a controller 20.

[0012] The sewing machine frame 3 is installed on an upper surface of a sewing machine table 2. The sewing machine table 2 is supported on table legs. A chair is installed at the rear of the sewing machine table 2. An operator of the sewing machine 1 operates the sewing machine 1 while sitting on the chair.

[0013] The needle bar 5 holds a sewing machine needle 4. The needle bar 5 reciprocates in an up-down direction. The needle bar 5 is supported by the sewing machine frame 3. The sewing machine needle 4 has a threading hole through which an upper thread passes. The sewing machine needle 4 holds the upper thread on an inner surface of the threading hole. As the needle bar 5 reciprocates in the up-down direction, the sewing machine needle 4 reciprocates in the up-down direction while holding the upper thread.

[0014] The thread take-up lever 6 supplies the upper thread to the sewing machine needle 4. The thread take-up lever 6 reciprocates in the up-down direction. The thread take-up lever 6 is supported by the sewing machine frame 3. The thread take-up lever 6 reciprocates in the up-down direction while holding the upper thread. The thread take-up lever 6 has a holding hole through which the upper thread passes. The thread take-up lever 6 holds the upper thread on an inner surface of the holding hole. The thread take-up lever 6 feeds out or pulls up the upper thread used for sewing a sewing workpiece 40 by reciprocating in the up-down direction.

[0015] The needle plate 7 supports the sewing workpiece 40 from below. The needle plate 7 supports the sewing workpiece 40 below the needle bar 5. The needle plate 7 is arranged below the needle bar 5. The sewing machine needle 4 held by the needle bar 5 and the needle plate 7 face each other. The needle plate 7 has a needle hole through which the sewing machine needle 4 can pass. The sewing machine needle 4, which penetrates the sewing workpiece 40 supported on the needle plate 7, passes through the needle hole.

[0016] The presser 8 presses the sewing workpiece 40 supported on the needle plate 7 from above. The presser 8 is arranged at least partially around the sewing machine needle 4. The presser 8 is supported by the sewing machine frame 3.

[0017] The thread tensioner 9 is provided between the thread take-up lever 6 and the needle bar 5 and applies tension to the upper thread supplied to the sewing machine needle 4. The thread tensioner 9 is supported by the sewing machine frame 3.

[0018] The shuttle 10 supplies a lower thread to the sewing workpiece 40. The shuttle 10 is arranged lower than the needle plate 7. The shuttle 10 is rotatable.

[0019] Each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 operates to feed the sewing workpiece 40 supported on the needle plate 7 forward or rearward. Each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 feeds the sewing workpiece 40 by moving along a predetermined feed path. Each of the main feed dog 11 and the auxiliary feed dog 12 is arranged below the needle plate 7. The upper feed dog 13 is arranged above the needle plate 7. Each of the main feed dog 11 and the auxiliary feed dog 12 protrudes from and retracts into an opening provided in the needle plate 7 as it moves along the feed path. When feeding the sewing workpiece 40, each of the main feed dog 11 and the auxiliary feed dog 12 protrudes upward from an upper surface of the needle plate 7 through the opening provided in the needle plate 7.

[0020] The sewing machine motor 14 generates power to operate the sewing machine power transmission mechanism 16. The adjustment motor 15 generates power to operate the feed amount adjustment mechanism 17. The sewing machine motor 14 includes a servo motor. The adjustment motor 15 includes a pulse motor.

[0021] The sewing machine power transmission mechanism 16 operates each of the needle bar 5, the shuttle 10, the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 based on the power generated by the sewing machine motor 14. The sewing machine power transmission mechanism 16 transmits the power generated by the sewing machine motor 14 to each of the needle bar 5, the shuttle 10, the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13. The needle bar 5 reciprocates in the up-down direction by an operation of the sewing machine power transmission mechanism 16. The shuttle 10 rotates by the operation of the sewing machine power transmission mechanism 16 so that the lower thread is supplied to the sewing workpiece 40, in synchronization with the reciprocation of the needle bar 5 in the up-down direction. Each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 moves along the feed path to feed the sewing workpiece 40 by the operation of the sewing machine power transmission mechanism 16, in synchronization with the reciprocation of the needle bar 5 in the up-down direction. The sewing machine 1 sews the sewing workpiece 40 through cooperation between the sewing machine needle 4 held by the needle bar 5 and the shuttle 10.

[0022] Note that each of the needle bar 5, the shuttle 10, the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 may be operated based on the power generated by the sewing machine motor 14, or a motor for individually operating each of the needle bar 5, the shuttle 10, the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 may be provided in the sewing machine 1.

[0023] The feed amount adjustment mechanism 17 changes at least one of a main feed amount Fm, which indicates a feed amount of the main feed dog 11, an auxiliary feed amount Fd, which indicates a feed amount of the auxiliary feed dog 12, and an upper feed amount Ft, which indicates a feed amount of the upper feed dog 13, based on the power generated by the adjustment motor 15. The main feed amount Fm is constant. The feed amount adjustment mechanism 17 changes at least one of the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm based on the power generated by the adjustment motor 15.

[0024] The pedal 18 is operated by the operator of the sewing machine 1. The operator operates the pedal 18 with a foot. The sewing machine motor 14 is driven or stopped based on an operating state of the pedal 18. An operating signal generated as a result of the pedal 18 being operated is transmitted to the controller 20.

[0025] The operation panel 19 includes a flat-panel display and a touch panel. The operation panel 19 functions as a display device and an input device. The operation panel 19 is operated by the operator of the sewing machine 1. The operation panel 19 is provided on the sewing machine frame 3. The operator operates the operation panel 19 with a finger. An input signal generated as a result of the operation panel 19 being operated is transmitted to the controller 20.

[0026] The controller 20 includes a computer system. The controller 20 outputs control commands for controlling each of the sewing machine motor 14 and the adjustment motor 15.

[0027] The controller 20 can communicate with an external computer 31 via a communication system 30. Examples of the external computer 31 include a personal computer. Examples of the communication system 30 include the Internet, a mobile phone communication network, a satellite communication network, or a local area network (LAN). The external computer 31 may be installed in the sewing factory where the sewing machine 1 is installed, or may be installed outside the sewing factory.

[0028] In the external computer 31, sewing data, which indicates sewing conditions of the sewing machine 1 is generated. The sewing data generated in the external computer 31 is transmitted to the controller 20 via the communication system 30.

[0029] The controller 20 controls the sewing machine motor 14 based on the operation signal from the pedal 18. When the pedal 18 is operated so that a front portion of the pedal 18 moves downward, the controller 20 drives the sewing machine motor 14. As the sewing machine motor 14 is driven, the sewing workpiece 40 is sewn. When the pedal 18 is operated so that a rear portion of the pedal 18 moves downward, the controller 20 stops the sewing machine motor 14.

[0030] The controller 20 sets the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm based on the sewing data from the external computer 31. The controller 20 controls the adjustment motor 15 based on the set feed amounts (Fm, Fd, and Ft).

[0031] The controller 20 controls the adjustment motor 15 so that at least one of the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm changes, based on an input signal from the operation panel 19.[Feed Amounts]

[0032] FIG. 4 is a schematic diagram showing the needle plate 7, the presser 8, the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 according to an embodiment. The needle plate 7 supports the sewing workpiece 40 from below. The presser 8 presses the sewing workpiece 40 supported on the needle plate 7 from above. Each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 operates to feed the sewing workpiece 40 forward. The sewing workpiece 40 includes a lower fabric 41 and an upper fabric 42. The upper fabric 42 is arranged higher than the lower fabric 41. The presser 8 and the upper feed dog 13 are arranged higher than the upper fabric 42. The main feed dog 11 and the auxiliary feed dog 12 are arranged lower than the lower fabric 41. The auxiliary feed dog 12 is arranged rearward of the main feed dog 11.

[0033] Each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 feeds the sewing workpiece 40 forward by moving along a predetermined feed path. Each of the main feed dog 11 and the auxiliary feed dog 12 is arranged lower than the sewing workpiece 40. The upper feed dog 13 is arranged higher than the sewing workpiece 40. The main feed dog 11 can come into contact with the lower fabric 41 from below the lower fabric 41 through the opening provided in the needle plate 7. The auxiliary feed dog 12 can come into contact with the lower fabric 41 from below the lower fabric 41 through the opening provided in the needle plate 7. The upper feed dog 13 can come into contact with the upper fabric 42 from above the upper fabric 42.

[0034] The main feed dog 11 moves along a main feed path Rm, which indicates a feed path of the main feed dog 11, to feed the lower fabric 41 forward. The auxiliary feed dog 12 moves along an auxiliary feed path Rd, which indicates a feed path of the auxiliary feed dog 12, to feed the lower fabric 41 forward. The upper feed dog 13 moves along an upper feed path Rt, which indicates a feed path of the upper feed dog 13, to feed the upper fabric 42 forward.

[0035] The main feed path Rm has a substantially elliptical shape that is long in a front-rear direction. Note that the main feed path Rm may have a rectangular shape that is long in the front-rear direction. The main feed path Rm includes a start position Sm and an end position Em of a feeding operation of the main feed dog 11. The start position Sm is defined rearward of the end position Em. The start position Sm is defined as a rear end portion of the main feed path Rm. The end position Em is defined as a front end portion of the main feed path Rm. The main feed path Rm includes a forward path along which the main feed dog 11 moves from the start position Sm to the end position Em, and a return path along which the main feed dog 11 moves from the end position Em to the start position Sm. In the forward path, the main feed dog 11 moves from the start position Sm to the end position Em while in contact with the lower fabric 41. In the forward path, the main feed dog 11 protrudes upward from the opening provided in the needle plate 7, thereby coming into contact with the lower fabric 41. In the return path, the main feed dog 11 moves from the end position Em to the start position Sm while being downwardly separated from the lower fabric 41. In the return path, the main feed dog 11 moves below the needle plate 7.

[0036] The auxiliary feed path Rd has a substantially elliptical shape that is long in a front-rear direction. Note that the auxiliary feed path Rm may have a rectangular shape that is long in the front-rear direction. The auxiliary feed path Rd includes a start position Sd and an end position Ed of a feeding operation of the auxiliary feed dog 12. The start position Sd is defined rearward of the end position Ed. The start position Sd is defined as a rear end portion of the auxiliary feed path Rd. The end position Ed is defined as a front end portion of the auxiliary feed path Rd. The auxiliary feed path Rd includes a forward path along which the auxiliary feed dog 12 moves from the start position Sd to the end position Ed, and a return path along which the auxiliary feed dog 12 moves from the end position Ed to the start position Sd. In the forward path, the auxiliary feed dog 12 moves from the start position Sd to the end position Ed while in contact with the lower fabric 41. In the forward path, the auxiliary feed dog 12 protrudes upward from the opening provided in the needle plate 7, thereby coming into contact with the lower fabric 41. In the return path, the auxiliary feed dog 12 moves from the end position Ed to the start position Sd while being downwardly separated from the lower fabric 41. In the return path, the auxiliary feed dog 12 moves below the needle plate 7.

[0037] The upper feed path Rt has a substantially elliptical shape that is long in a front-rear direction. Note that the upper feed path Rt may have a long rectangular shape that is long in the front-rear direction. The upper feed path Rt includes a start position St and an end position Et of a feeding operation of the upper feed dog 13. The start position St is defined rearward of the end position Et. The start position St is defined as a rear end portion of the upper feed path Rt. The end position Et is defined as a front end portion of the upper feed path Rt. The upper feed path Rt includes a forward path along which the upper feed dog 13 moves from the start position St to the end position Et, and a return path along which the upper feed dog 13 moves from the end position Et to the start position St. In the forward path, the upper feed dog 13 moves from the start position St to the end position Et while in contact with the upper fabric 42. In the return path, the upper feed dog 13 moves from the end position Et to the start position St while being upwardly separated from the upper fabric 42.

[0038] The main feed amount Fm, which indicates the feed amount of the main feed dog 11, is a distance between the start position Sm and the end position Em of the main feed path Rm in the front-rear direction. The auxiliary feed amount Fd, which indicates the feed amount of the auxiliary feed dog 12, is a distance between the start position Sd and the end position Ed of the auxiliary feed path Rd in the front-rear direction. The upper feed amount Ft, which indicates the feed amount of the upper feed dog 13, is a distance between the start position St and the end position Et of the upper feed path Rt in the front-rear direction.

[0039] When the main feed dog 11 moves along the forward path of the main feed path Rm, the auxiliary feed dog 12 moves along the forward path of the auxiliary feed path Rd, and the upper feed dog 13 moves along the forward path of the upper feed path Rt. When the main feed dog 11 moves along the return path of the main feed path Rm, the auxiliary feed dog 12 moves along the return path of the auxiliary feed path Rd, and the upper feed dog 13 moves along the return path of the upper feed path Rt.

[0040] With the sewing machine needle 4 raised and separated from the sewing workpiece 40, each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 moves along the forward path while in contact with the sewing workpiece 40. Each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 moves along the forward path while in contact with the sewing workpiece 40, so that the sewing workpiece 40 is fed forward. With the sewing machine needle 4 lowered and penetrating through the sewing workpiece 40, each of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 moves along the return path while being separated from the sewing workpiece 40. In conjunction with the up-down movement of the sewing machine needle 4, the respective feeding operations of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 are repeated, thereby forming stitches one by one in the sewing workpiece 40.[Relationship Between Feed Amounts and Sewing Workpiece]

[0041] Each of FIG. 5 and FIG. 6 is a diagram for describing a relationship among the main feed amount Fm, the auxiliary feed amount Fd, the upper feed amount Ft, and a sewn product 43 according to the embodiment. The sewn product 43 is produced by sewing the upper fabric 42 and the lower fabric 41.

[0042] As combinations of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft, first to twelfth patterns shown in FIGS. 5 and 6 are exemplified.

[0043] In the case of the first pattern in which the main feed amount Fm, the upper feed amount Ft, and the auxiliary feed amount Fd are equal, each of the upper fabric 42 and the lower fabric 41 is flat in the sewn product 43.

[0044] In the case of the second pattern in which the main feed amount Fm and the auxiliary feed amount Fd are equal and the upper feed amount Ft is greater than the auxiliary feed amount Fd, the lower fabric 41 is flat and pleats are formed on the upper fabric 42 in the sewn product 43.

[0045] In the case of the third pattern in which the main feed amount Fm and the upper feed amount Ft are equal and the auxiliary feed amount Fd is greater than the upper feed amount Ft, the upper fabric 42 is flat and pleats are formed on the lower fabric 41 in the sewn product 43.

[0046] In the case of the fourth pattern in which the main feed amount Fm is smaller than the auxiliary feed amount Fd and the auxiliary feed amount Fd and the upper feed amount Ft are equal, pleats are formed on each of the upper fabric 42 and the lower fabric 41 in the sewn product 43.

[0047] In the case of the fifth pattern in which the auxiliary feed amount Fd is smaller than the upper feed amount Ft and the upper feed amount Ft and the main feed amount Fm are equal, the upper fabric 42 is flat and the lower fabric 41 is stretched in the front-rear direction in the sewn product 43.

[0048] In the case of the sixth pattern in which the upper feed amount Ft is smaller than the auxiliary feed amount Fd and the auxiliary feed amount Fd and the main feed amount Fm are equal, the lower fabric 41 is flat and the upper fabric 42 is stretched in the front-rear direction in the sewn product 43.

[0049] In the case of the seventh pattern in which the main feed amount Fm is smaller than the auxiliary feed amount Fd and the auxiliary feed amount Fd is smaller than the upper feed amount Ft, pleats are formed on each of the lower fabric 41 and the upper fabric 42 in the sewn product 43. The pleats of the upper fabric 42 are larger than those of the lower fabric 41.

[0050] In the case of the eighth pattern in which the main feed amount Fm is smaller than the upper feed amount Ft and the upper feed amount Ft is smaller than the auxiliary feed amount Fd, pleats are formed on each of the lower fabric 41 and the upper fabric 42 in the sewn product 43. The pleats of the lower fabric 41 are larger than those of the upper fabric 42.

[0051] In the case of the ninth pattern in which the auxiliary feed amount Fd is smaller than the main feed amount Fm and the main feed amount Fm is smaller than the upper feed amount Ft, pleats are formed on the upper fabric 42 and the lower fabric 41 is stretched in the front-rear direction in the sewn product 43.

[0052] In the case of the tenth pattern in which the upper feed amount Ft is smaller than the main feed amount Fm and the main feed amount Fm is smaller than the upper feed amount Ft, pleats are formed on the lower fabric 41 and the upper fabric 42 is stretched in the front-rear direction in the sewn product 43.

[0053] In the case of the eleventh pattern in which the auxiliary feed amount Fd is smaller than the upper feed amount Ft and the upper feed amount Ft is smaller than the main feed amount Fm, each of the lower fabric 41 and the upper fabric 42 is stretched in the front-rear direction in the sewn product 43. An amount by which the lower fabric 41 is stretched in the front-rear direction is greater than an amount by which the upper fabric 42 is stretched in the front-rear direction.

[0054] In the case of the twelfth pattern in which the upper feed amount Ft is smaller than the auxiliary feed amount Fd and the auxiliary feed amount Fd is smaller than the main feed amount Fm, each of the lower fabric 41 and the upper fabric 42 is stretched in the front-rear direction in the sewn product 43. An amount by which the upper fabric 42 is stretched in the front-rear direction is greater than an amount by which the lower fabric 41 is stretched in the front-rear direction.[Controller]

[0055] FIG. 7 is a hardware configuration diagram showing the controller 20 according to an embodiment. The controller 20 includes a computer system 1000. The computer system 1000 includes a processor 1001 such as a central processing unit (CPU), a main memory 1002 including a nonvolatile memory such as a read only memory (ROM) and a volatile memory such as a random access memory (RAM), a storage 1003, and an interface 1004 including an input / output circuit. The functions of the controller 20 are stored in the storage 1003 as a computer program. The processor 1001 reads the computer program from the storage 1003, loads the computer program in the main memory 1002, and executes processing according to the computer program. Note that the computer program may be transmitted to the computer system 1000 via a network.

[0056] FIG. 8 is a functional block diagram showing the controller 20 according to an embodiment. The controller 20 includes a sewing data obtaining unit 21, an input signal obtaining unit 22, a calculation unit 23, and a control unit 24.

[0057] The sewing data obtaining unit 21 obtains sewing data indicating sewing conditions of the sewing machine 1. The sewing data obtaining unit 21 obtains the sewing data from the external computer 31. The sewing data includes a lower fabric length Ld, which indicates a length of the lower fabric 41, an upper fabric length Lt, which indicates a length of the upper fabric 42, and a finished length Lm, which indicates a target value of a length of the sewn product 43 after the lower fabric 41 and the upper fabric 42 are sewn.

[0058] FIG. 9 is a diagram for describing sewing data according to an embodiment. As shown in FIG. 9, the sewing data includes the lower fabric length Ld, which indicates a length of the lower fabric 41, the upper fabric length Lt, which indicates a length of the upper fabric 42, and the finished length Lm, which indicates a target value of a length of the sewn product 43 after the lower fabric 41 and the upper fabric 42 are sewn. In an embodiment, the sewn product 43 is produced such that a position of one end portion of the lower fabric 41 matches a position of one end portion of the upper fabric 42 and a position of the other end portion of the lower fabric 41 matches a position of the other end portion of the upper fabric 42. In addition, the sewn product 43 is produced such that an actual sewn product length Lr, which indicates an actual length of the sewn product 43, matches the finished length Lm. That is, the sewn product 43 is produced such that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr and the finished length Lm match.

[0059] FIG. 9 shows an example in which the combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft is the second pattern. As shown in FIG. 9, when the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is equal to the lower fabric length Ld, pleats are formed on the upper fabric 42 and the lower fabric 41 becomes flat so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0060] The input signal obtaining unit 22 obtains an input signal from the operation panel 19. The operation panel 19 functions as an input device. An input signal is generated as a result of the operation panel 19 being operated. The input signal obtaining unit 22 obtains the input signal generated as a result of the operation panel 19 being operated.

[0061] The calculation unit 23 calculates the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm based on the sewing data obtained by the sewing data obtaining unit 21 so that the actual sewn product length Lr becomes the finished length Lm.

[0062] For example, when the upper fabric length Lt, the lower fabric length Ld, and the finished length Lm are equal, the calculation unit 23 selects the first pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft.

[0063] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is equal to the lower fabric length Ld, the calculation unit 23 selects the second pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that pleats are formed on the upper fabric 42. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0064] When the upper fabric length Lt is shorter than the lower fabric length Ld and the finished length Lm is equal to the upper fabric length Lt, the calculation unit 23 selects the third pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that pleats are formed on the lower fabric 41. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0065] When the upper fabric length Lt and the lower fabric length Ld are equal and the finished length Lm is shorter than the lower fabric length Ld and the upper fabric length Lt, the calculation unit 23 selects the fourth pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that pleats are formed on both the lower fabric 41 and the upper fabric 42. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0066] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is equal to the upper fabric length Lt, the calculation unit 23 selects the fifth pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that the lower fabric 41 becomes stretched in the front-rear direction. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0067] When the upper fabric length Lt is shorter than the lower fabric length Ld and the finished length Lm is equal to the lower fabric length Ld, the calculation unit 23 selects the sixth pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that the upper fabric 42 becomes stretched in the front-rear direction. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0068] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is shorter than the lower fabric length Ld, the calculation unit 23 selects the seventh pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that pleats are formed on both the lower fabric 41 and the upper fabric 42. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0069] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is shorter than the upper fabric length Lt, the calculation unit 23 selects the eighth pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that pleats are formed on both the lower fabric 41 and the upper fabric 42. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0070] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is a length between the upper fabric length Lt and the lower fabric length Ld, the calculation unit 23 selects the ninth pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that pleats are formed on the upper fabric 42 and the lower fabric 41 becomes stretched in the front-rear direction. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0071] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is a length between the upper fabric length Lt and the lower fabric length Ld, the calculation unit 23 selects the tenth pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that pleats are formed on the lower fabric 41 and the upper fabric 42 becomes stretched in the front-rear direction. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0072] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is longer than the upper fabric length Lt, the calculation unit 23 selects the eleventh pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that both the upper fabric 42 and the lower fabric 41 become stretched in the front-rear direction. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0073] When the upper fabric length Lt is longer than the lower fabric length Ld and the finished length Lm is longer than the lower fabric length Ld, the calculation unit 23 selects the twelfth pattern as a combination of the main feed amount Fm, the auxiliary feed amount Fd, and the upper feed amount Ft so that both the upper fabric 42 and the lower fabric 41 become stretched in the front-rear direction. In addition, the calculation unit 23 calculates the auxiliary feed amount Fd relative to the main feed amount Fm and the upper feed amount Ft relative to the main feed amount Fm so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0074] The control unit 24 controls the respective feeding operations of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 based on the feed amounts (Fm, Fd, and Ft) calculated by the calculation unit 23 so that the actual sewn product length Lr matches the finished length Lm. In an embodiment, the control unit 24 controls the adjustment motor 15 so that the main feed dog 11 feeds the lower fabric 41 forward by the main feed amount Fm calculated by the calculation unit 23, the auxiliary feed dog 12 feeds the lower fabric 41 forward by the auxiliary feed amount Fd calculated by the calculation unit 23, and the upper feed dog 13 feeds the upper fabric 42 forward by the upper feed amount Ft calculated by the calculation unit 23.[Correction of Error]

[0075] FIG. 10 is a diagram for describing a relationship between the actual sewn product length Lr and the finished length Lm according to the embodiment. As described above, the calculation unit 23 calculates the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm based on the lower fabric length Ld, the upper fabric length Lt, and the finished length Lm such that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm. The control unit 24 controls the respective feeding operations of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 based on the feed amounts (Fm, Fd, and Ft) calculated by the calculation unit 23. As shown in FIG. 10, for example, due to the physical properties of the sewing workpiece 40, friction between the upper fabric 42 and the lower fabric 41, or the like, a deviation amount ΔLa between a length of the lower fabric 41 and a length of the upper fabric 42 may increase, or an error ΔLb between the actual sewn product length Lr and the finished length Lm may increase.

[0076] In an embodiment, trial sewing of the upper fabric 42 and the lower fabric 41 is performed based on the feed amounts (Fm, Fd, and Ft) calculated by the calculation unit 23. When the deviation amount ΔLa between the lower fabric 41 and the upper fabric 42 exceeds a first predetermined allowable value, or when the error ΔLb between the actual sewn product length Lr and the finished length Lm exceeds a second predetermined allowable value, at least one of the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm is corrected so that the deviation amount ΔLa and the error ΔLb are reduced. The operator of the sewing machine 1 operates the operation panel 19 to input the deviation amount ΔLa and the error ΔLb into the controller 20. The input signal obtaining unit 22 obtains input signals from the operation panel 19 indicating the deviation amount ΔLa and the error ΔLb. The calculation unit 23, based on the input signals from the operation panel 19 indicating the deviation amount ΔLa and the error ΔLb, corrects at least one of the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm so that the deviation amount ΔLa and the error ΔLb are reduced.

[0077] FIG. 11 is a diagram showing the operation panel 19 according to an embodiment. As shown in FIG. 11, the operation panel 19 has a first display area 51 that displays the upper feed amount Ft calculated by the calculation unit 23, a second display area 52 that displays the main feed amount Fm calculated by the calculation unit 23, and a third display area 53 that displays the auxiliary feed amount Fd calculated by the calculation unit 23. In addition, the operation panel 19 has a first input area 54 to which the deviation amount ΔLa is input, and a second input area 55 to which the error ΔLb is input. When the deviation amount ΔLa is input to the first input area 54 and the error ΔLb is input to the second input area 55, the calculation unit 23 corrects the feed amounts (Fm, Fd, and Ft) so that the deviation amount ΔLa and the error ΔLb are each reduced. The upper feed amount Ft after correction is displayed in the first display area 51, the main feed amount Fm after correction is displayed in the second display area 52, and the auxiliary feed amount Fd after correction is displayed in the third display area 53.[Sewing Method]

[0078] FIG. 12 is a flow chart showing a sewing method according to an embodiment. The sewing data obtaining unit 21 obtains sewing data including the lower fabric length Ld, the upper fabric length Lt, and the finished length Lm from the external computer 31 (step S1).

[0079] FIG. 13 is a schematic diagram showing sewing data according to an embodiment. The sewing data includes clothing design data. The clothing design data includes clothing CAD (Computer Aided Design) data. In the example shown in FIG. 13, the lower fabric 41 is a back body of clothing, and the upper fabric 42 is a front body of the clothing. A peripheral edge portion of the lower fabric 41 and a peripheral edge portion of the upper fabric 42 are sewn by the sewing machine 1. The sewing data includes the lower fabric length Ld, which indicates a length of the peripheral edge portion of the lower fabric 41, the upper fabric length Lt, which indicates a length of the peripheral edge portion of the upper fabric 42, and the finished length Lm.

[0080] The peripheral edge portion of the lower fabric 41 is divided into a plurality of portions, and the peripheral edge portion of the upper fabric 42 is divided into a plurality of portions. In the example shown in FIG. 13, the peripheral edge portion of the lower fabric 41 is divided into three portions, and the peripheral edge portion of the upper fabric 42 is divided into three portions. Lengths of the first portion, the second portion, and the third portion of the lower fabric 41 are a lower fabric length Ld1, a lower fabric length Ld2, and a lower fabric length Ld3, respectively. Lengths of the first portion, the second portion, and the third portion of the upper fabric 42 are an upper fabric length Lt1, an upper fabric length Lt2, and an upper fabric length Lt3, respectively. The lower fabric length Ld is a sum of the lower fabric length Ld1, the lower fabric length Ld2, and the lower fabric length Ld3. The upper fabric length Lt is a sum of the upper fabric length Lt1, the upper fabric length Lt2, and the upper fabric length Lt3. The first portion of the lower fabric 41 and the first portion of the upper fabric 42 are sewn. The second portion of the lower fabric 41 and the second portion of the upper fabric 42 are sewn. The third portion of the lower fabric 41 and the third portion of the upper fabric 42 are sewn.

[0081] The sewing data includes the lower fabric length Ld1, the lower fabric length Ld2, the lower fabric length Ld3, the upper fabric length Lt1, the upper fabric length Lt2, the upper fabric length Lt3, a finished length Lm1 after the first portion of the lower fabric 41 and the first portion of the upper fabric 42 are sewn, a finished length Lm2 after the second portion of the lower fabric 41 and the second portion of the upper fabric 42 are sewn, and a finished length Lm3 after the third portion of the lower fabric 41 and the third portion of the upper fabric 42 are sewn.

[0082] The calculation unit 23 calculates the auxiliary feed amount Fd and the upper feed amount Ft relative to the main feed amount Fm based on the sewing data obtained in step S1 (step S2).

[0083] The control unit 24 sews the lower fabric 41 and the upper fabric 42 while controlling the respective feeding operations of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 based on the feed amounts (Fm, Fd, and Ft) calculated in step S2 (step S3). In the embodiment, the sewing in step S3 is a trial sewing.

[0084] The operator of the sewing machine 1 measures the deviation amount ΔLa and the error ΔLb. When the deviation amount ΔLa exceeds the first allowable value, the operator operates the operation panel 19 to input the deviation amount ΔLa to the controller 20. When the error ΔLb exceeds the second allowable value, the operator the operation panel 19 to input the error ΔLb to the controller 20.

[0085] The calculation unit 23 determines whether the deviation amount ΔLa and the error ΔLb have been input (step S4).

[0086] In step S4, if it is determined that the deviation amount ΔLa and the error ΔLb are not input (step S4: No), the control unit 24 sews the lower fabric 41 and the upper fabric 42 while controlling the respective feeding operations of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 based on the feed amounts (Fm, Fd, and Ft) calculated in step S2 (step S5). In the embodiment, the sewing in step S5 is an actual sewing.

[0087] In step S4, if it is determined that the deviation amount ΔLa and error ΔLb have been input (step S4: Yes), the calculation unit 23 corrects the feed amounts (Fm, Fd, and Ft) based on the deviation amount ΔLa and the error ΔLb (step S6).

[0088] For example, as shown in FIG. 10, when the upper fabric 42 is shorter than the lower fabric 41, the upper feed amount Ft is corrected to a value smaller by a predetermined value ΔLc so that the deviation amount ΔLa and the error ΔLb are each reduced. The predetermined value ΔLc is a value obtained by subtracting the error ΔLb from the deviation amount ΔLa. The auxiliary feed amount Fd is corrected to a value smaller than by the error ΔLb. When the upper fabric 42 is longer than the lower fabric 41, the upper feed amount Ft is corrected to a value smaller than by the error ΔLb so that the deviation amount ΔLa and the error ΔLb are each reduced. The auxiliary feed amount Fd is corrected to a value smaller than by the predetermined value ΔLc.

[0089] After the feed amounts (Fm, Fd, and Ft) are corrected, the processing returns to step S3. The processing of steps S3, S4, and S6 is repeated until the deviation amount ΔLa and the error ΔLb become small.[Effects]

[0090] As described above, the sewing machine 1, which is a differential feed sewing machine 1, includes the main feed dog 11 that feeds the lower fabric 41, the auxiliary feed dog 12 that feeds the lower fabric 41, the upper feed dog 13 that feeds the upper fabric 42, and the controller 20. The controller 20 includes the sewing data obtaining unit 21 that obtains sewing data including the lower fabric length Ld, which indicates the length of the lower fabric 41, the upper fabric length Lt, which indicates the length of the upper fabric 42, and the finished length Lm, which indicates a target value of the length of the sewn product 43 after the lower fabric 41 and the upper fabric 42 are sewn, the calculation unit 23 that calculates, based on the sewing data, the auxiliary feed amount Fd, which indicates the feed amount of the auxiliary feed dog 12, and the upper feed amount Ft, which indicates the feed amount of the upper feed dog 13, relative to the main feed amount Fm, which indicates the feed amount of the main feed dog 11, and the control unit 24 that controls the respective feeding operations of the main feed dog 11, the auxiliary feed dog 12, and the upper feed dog 13 based on the feed amounts (Fm, Fd, and Ft) calculated by the calculation unit 23.

[0091] According to an embodiment, when the lower fabric length Ld, the upper fabric length Lt, and the finished length Lm are input to the controller 20, the controller 20 calculates the optimal feed amounts (Fm, Fd, and Ft) so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm. Thus, the feed amounts (Fm, Fd, and Ft) in the sewing machine 1 are easily set.

[0092] The sewing machine 1 includes the operation panel 19 that functions as an input device. The controller 20 includes the input signal obtaining unit 22 that obtains an input signal from the operation panel 19. The calculation unit 23 corrects the feed amounts (Fm, Fd, and Ft) based on the input signal so that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm. Thus, even when the deviation amount ΔLa between the length of the lower fabric 41 and the length of the upper fabric 42 increases or the error ΔLb between the actual sewn product length Lr and the finished length Lm increases due to, for example, the physical properties of the sewing workpiece 40, the friction between the upper fabric 42 and the lower fabric 41, or the like, the feed amounts (Fm, Fd, and Ft) are corrected based on the input signal, and accordingly, the sewn product 43 is produced such that the positions of both end portions of the lower fabric 41 and the upper fabric 42 match and also the actual sewn product length Lr matches the finished length Lm.

[0093] The operation panel 19 has the first display area 51 for displaying the upper feed amount Ft calculated by the calculation unit 23, the second display area 52 for displaying the main feed amount Fm calculated by the calculation unit 23, the third display area 53 for displaying the auxiliary feed amount Fd calculated by the calculation unit 23, the first input area 54 to which the deviation amount ΔLa between the lower fabric length Ld and the upper fabric length Lt is input, and the second input area 55 to which the error ΔLb between the actual sewn product length Lr and the finished length Lm is input. When the deviation amount ΔLa is input to the first input area 54 and the error ΔLb is input to the second input area 55, the calculation unit 23 corrects the feed amounts (Fm, Fd, and Ft) so that the deviation amount ΔLa and the error ΔLb are each reduced. The upper feed amount Ft after correction is displayed in the first display area 51, the main feed amount Fm after correction is displayed in the second display area 52, and the auxiliary feed amount Fd after correction is displayed in the third display area 53. Thus, the operator of the sewing machine 1 can input the deviation amount ΔLa and the error ΔLb to the operation panel 19 when the deviation amount ΔLa and the error ΔLb are large. Additionally, the operator of the sewing machine 1 can check the feed amounts (Fm, Fd, and Ft) after correction displayed on the operation panel 19.

[0094] The sewing data obtaining unit 21 obtains the sewing data from the external computer 31 via the communication system 30. Thus, the operator of the sewing machine 1 does not need to input the sewing data to the controller 20, so the burden on the operator is reduced.

Claims

1. A differential feed sewing machine comprising: a main feed dog configured to feed a lower fabric; an auxiliary feed dog configured to feed the lower fabric; an upper feed dog configured to feed an upper fabric; and a controller, wherein the controller comprises a sewing data obtaining unit configured to obtain sewing data comprising a lower fabric length, which indicates a length of the lower fabric, an upper fabric length, which indicates a length of the upper fabric, and a finished length, which indicates a target value of a length of a sewn product after the lower fabric and the upper fabric are sewn; a calculation unit configured to calculate a feed amount of the auxiliary feed dog and a feed amount of the upper feed dog relative to a feed amount of the main feed dog based on the sewing data, and a control unit configured to control respective feeding operations of the main feed dog, the auxiliary feed dog, and the upper feed dog based on the feed amounts calculated by the calculation unit.

2. The differential feed sewing machine according to claim 1, further comprising an input device, wherein the controller comprises an input signal obtaining unit configured to obtain an input signal from the input device, and the calculation unit is configured to correct the feed amounts based on the input signal.

3. The differential feed sewing machine according to claim 2, wherein the input signal obtaining unit is configured to obtain an input signal, which indicates a deviation amount between the lower fabric length and the upper fabric length after sewing, and an input signal, which indicates an error between an actual sewn product length and the finished length, and the calculation unit is configured to correct the feed amounts based on the input signals.

4. The differential feed sewing machine according to claim 2, wherein the input device comprises a first display area for displaying an upper feed amount calculated by the calculation unit, a second display area for displaying a main feed amount calculated by the calculation unit, a third display area for displaying an auxiliary feed amount calculated by the calculation unit, a first input area to which a deviation amount between the lower fabric length and the upper fabric length is input, and a second input area to which an error between an actual sewn product length and the finished length is input, when the deviation amount is input to the first input area and the error is input to the second input area, the calculation unit corrects the feed amounts so that the deviation amount and the error are each reduced, and the upper feed amount after correction is displayed in the first display area, the main feed amount after correction is displayed in the second display area, and the auxiliary feed amount after correction is displayed in the third display area.

5. The differential feed sewing machine according to claim 1, wherein the sewing data obtaining unit is configured to obtain the sewing data from an external computer via a communication system.

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