US20130152838A1

US20130152838A1 - Sewing Machine

Info

Publication number: US20130152838A1
Application number: US13/720,380
Authority: US
Inventors: Mitsunori Matsumoto
Original assignee: Tokai Kogyo Sewing Machine Co Ltd
Current assignee: Tokai Kogyo Sewing Machine Co Ltd
Priority date: 2011-12-20
Filing date: 2012-12-19
Publication date: 2013-06-20
Also published as: JP2013128551A; CN203096375U; DE102012024755A1; KR20130071399A

Abstract

A pulling device is configured to grip, after cutting of a sewing material, a suitable portion of the sewing material by means of a grip member, where a leading end portion of the sewing material having been pulled out from a guide device, and pull back the sewing material by movement of the grip member having the sewing material gripped thereby. Thus, the leading end portion of the sewing material, pulled out and extending from the guide device more than necessary, can be minimized to a length necessary for the sewing material to be reliably sewn onto a sewing object at an initial stage of a next sewing operation. In this way, it is possible to minimize a length of a portion of the sewing material that was heretofore wasted without being sewn onto the sewing object.

Description

BACKGROUND

The present invention relates to sewing machines of a type provided with a cutting device that, in response to completion of a sewing operation where a tape or cord or other elongated sewing material having been guided by a guide device to a needle drop position is sewn by lock stitching onto a sewing workpiece or sewing object (e.g., fabric) through loop stitching, pulls out the sewing material from the guide device and cuts the pulled-out elongated sewing material.
Heretofore, there have been known sewing machines of a type which includes: a vertically-driven needle bar; a sewing needle fixed to the lower end of the needle bar; a rotary member mounted concentrically with the needle bar and freely rotatable about the axis of the needle bar; and a guide device (guide) fixed to the rotary member for guiding an elongated sewing material (e.g., string-shaped embroidering material, such as a tape or cord) to a needle drop position of the sewing needle. The sewing machines of this type operate to sew the sewing material to the sewing workpiece or sewing object (e.g., fabric) by lock stitching while controlling the rotation of the rotary member in accordance with a moving direction of the sewing object based on embroidery data and appropriately adjusting the orientation of the guide to optimize the direction in which the sewing material is guided to the needle drop position of the sewing needle. Some of the conventionally-known sewing machines of the aforementioned type are provided with a cutting device for automatically cutting the sewing material, having been pulled out to the needle drop position, with a view to reducing a load imposed on a human operator when an operation for sewing the sewing material to the sewing object has been completed. An example of such sewing machines is known from Japanese Patent Application Laid-open Publication No. 2007-68829 (hereinafter referred to as “relevant patent literature”).
In the sewing machine disclosed in the aforementioned relevant patent literature, the cutting device for cutting the sewing material is located apart from the needle drop position. Now briefly explaining the cutting device disclosed in the relevant patent literature, the cutting device includes a cutting member movable between an evacuation position where the cutting device does not disturb the sewing operation and a cutting position where it can cut the sewing material. When the sewing material is to be cut, the sewing object is moved to move a sewing end point of the sewing material from the needle drop position to near the cutting device, and then the cutting member is moved from the evacuation position to the cutting position.
The cutting member disclosed in the relevant patent literature includes a catch section that catches the sewing material as the cutter member moves from the evacuation position to the cutting position, a cutting blade that operates in response to further movement of the cutter member to the cutting position after the catch section has caught the sewing material, and a fixed blade that cuts the sewing material in conjunction with the cutting blade. Namely, as the cutting member moves from the evacuation position to the cutting position, the sewing material is caught by the catch member, and the cutting blade is moved, in interlocked relation to the further movement of the cutting member with the sewing material caught by the catch member, so that the sewing material is cut through cooperation between the cutting blade and the fixed blade.
In the sewing machines of the aforementioned type, a leading end portion of the sewing material, pulled to extend out from the guide in preparation for a next sewing operation, has to have a given length such that the sewing material can be reliably sewn to the sewing object at an initial stage of the next sewing operation. Thus, the sewing machines provided with the cutting device as disclosed in the relevant patent literature is constructed to secure a sufficient length of the leading end portion of the sewing material that should extend out from the guide after completion of the cutting operation, by moving the sewing object by some extra distance from the guide at the time of the cutting of the sewing material. By securing such a sufficient length of the leading end portion of the sewing material which should extend out from the guide in preparation for a next sewing operation, it is possible to reliably sew the sewing material onto the sewing object at the initial stage of a next sewing operation.
However, in the cutting device disclosed in the aforementioned relevant patent literature, the leading end portion of the sewing material tends to extend out from the guide after completion of the cutting operation more than the length necessary for the sewing material to be reliably sewn at the initial stage of a next sewing operation, because a mounted position of the cutting device depends on positional relationship among various component parts fixed to a machine head, the member rotation-controlled in accordance with a moving direction of the sewing object, etc. Further, because of the fact that the sewing material is sewn to the sewing object starting at a sewing start point located near the guide, most of the leading end portion of the sewing material, extending out from the guide, would not be sewn onto the sewing object at the initial stage of a next sewing operation. Because such a portion of the sewing material that could not be sewn onto the sewing object is discarded after being cut manually by the human operator, that portion of the sewing material would result in a considerable waste.
In order to avoid such a waste of the sewing material, it is preferable to minimize the length of the leading end portion of the sewing material extending out from the guide while at the same time securing the length necessary for the sewing material to be reliably sewn onto the sewing object at the initial stage of a next sewing operation. Further, because the necessary length for the sewing material to be reliably sewn onto the sewing object differs depending on the types of the sewing material and the sewing object, it is preferable to permit desired adjustment of the length of the leading end portion of the sewing material, extending out from the guide before that start of a sewing operation, depending on the types of the sewing material and the sewing object. However, no sewing machine capable of realizing such a minimized length of the leading end portion and desired adjustment of the length of the leading end portion has not been proposed yet.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention to provide an improved sewing machine which includes a cutting device that, in response to completion of sewing of a sewing material onto a sewing object, pulls out and cuts a leading end portion of the sewing material, and which can minimize the length of the leading end portion of the sewing material extending out from a guide while at the same time securing a length necessary for the sewing material to be reliably sewn onto the sewing object at the initial stage of a next sewing operation.
It is another object of the present invention to provide an improved sewing machine which permits desired adjustment of a length of a leading end portion of the sewing material, which extends out from a guide before the start of a sewing operation, depending on types of the sewing material and sewing object.
In order to accomplish the above-mentioned objects, the present invention provides an improved sewing machine, which comprises: a sewing needle mounted to a lower end portion of a vertically-driven needle bar; a guide device for guiding an elongated sewing material to a needle drop position of the sewing needle in response to a sewing operation for sewing the sewing material onto a sewing object; a cutting device for cutting the sewing material after moving the sewing object, having the sewing material sewn thereon through lock stitching, so that a sewing end point of the sewing material is moved from the needle drop position to be located at a predetermined position away from the needle drop position and then pulling the sewing material out from the guide device; and a pulling device for pulling back the sewing material, whose leading end portion has been pulled out from the guide device, after the cutting by the cutting device, and thereby reducing a length of a leading end portion of the sewing material extending out from the guide device.
In a preferred embodiment of the sewing machine, the pulling device includes a grip device for gripping the sewing material, and a drive device for moving the grip device, and the pulling device pulls back the sewing material, whose leading end portion has been pulled out from the guide device, after the cutting by the cutting device, by the drive device moving the grip device with the sewing material gripped thereby.
According to the present invention, the pulling device pulls back, after the cutting of the sewing material, the sewing material having its leading end portion pulled to extend out from the guide device. Thus, a leading end portion of the sewing material, extending out from the guide device more than necessary, can be minimized to a length necessary for the sewing material to be reliably sewn onto the sewing object at an initial stage of a next sewing operation. In this way, it is possible to minimize a length of a portion of the sewing material that was heretofore wasted without being sewn onto the sewing object.
Further, with the present invention, it is possible to change as desired a length by which the sewing material, pulled out from the guide device, is to be pulled back after the cutting, by the drive device moving the grip device, having the cut sewing material gripped thereby, to pull back the pulled-out sewing material and by changing the timing at which the sewing material should be released, via the release device, from the gripping by the grip device. In this way, a human operator can readily adjust the length of the leading end portion of the sewing material, which should extend out from the guide in preparation for a next sewing operation, to a desired length depending on the types of the sewing material and sewing object.
According to the present invention, the sewing material, pulled out from the guide device, is gripped and pulled back after the cutting, by the cutting device, of the sewing material. Thus, the leading end portion of the sewing material, extending out from the guide device more than necessary, can be minimized to a length necessary for the sewing material to be reliably sewn onto a sewing object at an initial stage of a next sewing operation. In this way, it is possible to minimize a length of a portion of the sewing material that would be wasted without being sewn onto the sewing object.
Further, because a length by which the sewing material, whose leading end portion has been pulled out from the guide device, should be pulled back can be adjusted in accordance with a change in the timing for releasing, via the release device, the sewing material from the gripping by the grip device, the human operator can readily adjust the length of the leading end portion of the sewing material, which should extend out from the guide device in preparation for a next sewing operation, to a desired length depending on the types of the sewing material and sewing object.
The following will describe embodiments of the present invention, but it should be appreciated that the present invention is not limited to the described embodiments and various modifications of the invention are possible without departing from the basic principles. The scope of the present invention is therefore to be determined solely by the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

For better understanding of the object and other features of the present invention, its preferred embodiments will be described hereinbelow in greater detail with reference to the accompanying drawings, in which:

FIG. 1 is a plan view showing an embodiment of a multi-head embroidery sewing machine of the present invention;

FIG. 2 is a front view showing an example of a supply stand;

FIG. 3 is a plan view showing a stored state of an original fabric on the supply stand;

FIG. 4 is a front view showing an example of a machine head in the embroidery sewing machine;

FIG. 5 is a left side view showing the example of the machine head;

FIG. 6 is a schematic front view showing an example of a pulling device in the embroidery sewing machine;

FIG. 7 is a schematic plan view explanatory of pulling of a sewing material and particularly showing a sliding block in a raised position; and

FIG. 8 is a schematic plan view explanatory of the pulling of the sewing material and particularly showing the sliding block in a lowered position.

DETAILED DESCRIPTION

The following describe in detail a preferred embodiment of the present invention with reference to the accompanying drawings.
FIG. 1 is a plan view showing a preferred embodiment of an embroidery sewing machine of the present invention, FIG. 2 is a front view of an example of a supply stand S, and FIG. 3 is a plan view showing a stored state of an original fabric N on the supply stand S. Hereinbelow, a preferred embodiment of a multi-head embroidery sewing machine having a plurality of machine heads will be described with primary reference to FIGS. 1 to 3. Note that, in FIG. 1, the multi-head embroidery sewing machine is shown with an upper section of a machine frame 1 recessed and thus illustration of the later-described machine heads (see FIGS. 4 and 5) is omitted.
A plurality of machine heads are provided on the front surface (corresponding to the lower end side in FIG. 1 and the surface closer to a reader of FIG. 2) at predetermined intervals along a left-right direction of the multi-head embroidery sewing machine. Each of the machine heads is capable of sewing an elongated sewing material, such as a tape or cord, to a sewing workpiece or sewing object, such as a fabric, leather or other material. A table 2 of a flat plate shape is provided underneath these machine heads. Needle plates 3 are provided on the table 2 at positions corresponding to the positions of the machine heads. Further, a fabric frame 4 for holding a sewing object (also referred to also as “original fabric”) N is placed on the table 2, and the fabric frame 4 is drivable in front-rear and left-right directions along the table 2 by means of an X drive mechanism 5 and a Y drive mechanism 6 provided underneath the table 2.
In the instant embodiment of the multi-head embroidery sewing machine, an elongated original fabric N is supplied from a supply source S (i.e., later-described supply stand S) to the fabric frame 4 so that a portion of the original fabric N is fixedly held on the fabric frame 4. Once sewing of the sewing material onto the portion of the original fabric N fixedly held on the fabric frame 4 is completed, the original fabric N is moved relative to the fabric frame 4 so that another portion of the original fabric N is fixedly held on the fabric frame 4, and then, the sewing is re-started to sew the sewing material to the other portion of the original fabric N.
In order to fixedly hold one or more original fabrics N on each of left and right machine sections demarcated along a centerline extending across the width of the embroidery sewing machine, two pairs of front and rear horizontal clamp members 7 a and 7 b are disposed on left and right side sections on the fabric frame 4 in opposed relation to each other. On each of the clamp members 7 a and 7 b, pairs of guide members 12 are provided in corresponding relation to individual original fabrics N for guiding left and right portions of the corresponding fabrics N. Each of the original fabrics N is passed between the corresponding pairs of guide members 12. Each pair of the guide members 12 opposed to each other in the left-right direction of FIG. 1 are adjustable in position in accordance with the width of the corresponding original fabric N. With one or more original fabrics N sandwiched between the pair of opposed horizontal clamp members 7 a and 7 b, the one or more original fabrics N supplied from the supply source S can be simultaneously fixed at respective predetermined positions of the fabric frame 4.
With the aforementioned construction where no machine head and needle plate 3 are provided in a middle region of the fabric frame 4, the sewing material cannot be sewn to the original fabric M on the central region of the fabric frame 4. Instead, in the middle region of the fabric frame 4, a reinforcing member 8 spans between and is fixed to the front and rear sides of the fabric frame 4, with a view to preventing deformation of the fabric frame 4 to thereby prevent differences in sewn position, on the individual original fabrics N, of the sewing materials that might be caused due to the deformation of the fabric frame 4.
Two supply stands S for supporting original fabrics N are provided behind the back or rear surface of the multi-head embroidery sewing machine in corresponding relation to the pairs of horizontal clamp members 7 a and 7 b that are provided on front and rear longitudinal edge portions of the fabric frame 4 and extending in the left-right direction of the fabric frame 4. These supply stands S are capable of supporting original fabrics N corresponding in number to the machine heads. As illustratively shown in FIG. 2, each of the supply stands S is constructed in a two-deck structure comprising upper and lower decks such that the original fabrics N to be used by the individual machine heads can be supported dividedly on the upper and lower decks in a vertically-staggered row.
In the supply stands S, as shown in FIGS. 2 and 3, one original fabric N is set in a rolled state on each drum 9. Pairs of support rods 10 parallel spaced from each other by a predetermined distance in the front-rear direction are provided; the number of the pairs of support rods 10 corresponds to the number of the machine heads. Per each of the pairs of support rods 10, four support rollers 11 are supported on opposite end portions of the front and rear support rods 10 in such a manner that the support rollers 11 are immovable in an axial direction thereof; the drum 9 is rotatably supported by the four support rollers 11. The original fabric N is supplied from each of the drums 9, supported on the supply stands S, to the fabric frame 4.
The following describe the machine head H having a function for sewing an elongated sewing material, such as a tape or cord, to an original fabric N fixedly held on the fabric frame 4. FIG. 4 is a front view showing an example of the machine head, and FIG. 5 is a left side view showing the example of the machine head.
The machine head H shown in FIGS. 4 and 5 has a sewing needle 14 mounted to a lower end portion of a needle bar disposed to extend in an up-down direction (vertical direction) of the sewing machine and reciprocatively driven, together with the needle bar in the up-down direction, by rotation of a main machine shaft 13. Lock stitching is performed in the well-known manner through the up-and-down (vertical) movement of the sewing needle 14 and rotation of a not-shown rotary hook disposed underneath a needle plate 3. In coaxial relation to the needle bar are provided a rotary member 15 freely rotatable about the axis of the needle bar, and a presser foot 16 not only rotatable together with the rotary member 15 but also vertically movable in response to the vertical movement of the sewing needle 14.
A guide lever 17 is mounted to the rotary member 15 and driven to reciprocatively pivot at predetermined timing relative to the vertical up-down movement of the needle bar 14, and a guide 18 is mounted to the distal end of the guide lever 17 for directing or guiding a sewing material A to a needle drop position (sewing position) of the sewing needle 14. The sewing machine sequentially sews the sewing material A, guided to the needle drop position of the sewing needle 14, onto the fabric N through zigzag sewing by reciprocatively pivoting the guide lever 17 leftward and rightward of the needle drop position per vertical reciprocating movement of the sewing needle 14 while controlling the rotation of the rotary member 15, in accordance with a moving direction of the fabric frame 4 based on embroidery data, in such a manner as to optimize a direction in which the sewing material A is to be guided.
A bobbin 19 having a cord-shaped sewing material A wound thereon is rotatably provided above the machine head H. More specifically, the bobbin 19 is rotatably supported on a bobbin shaft 21 that is in turn supported at its opposite ends on a pair of left and right support members 20 fixed to the machine frame 1. A support plate 22 extending downward is fixed to one of the pair of support members 20 (i.e., left support member 20 in FIG. 4). A driving pulley 23 is disposed at a position of the support plate 22 closer to the proximal end of the support plate 22, and this driving pulley 23 is fixedly connected to a motor shaft of a drive motor 24 fixed to the left support member 22.
A driven pulley 25 is rotatably disposed at a position, adjacent to the driving pulley 23, of the support plate 22 closer to the distal end of the support plate 22, and a round belt 26 is wound at its opposite end portions on the driven pulley 25 and the driving pulley 23. The driven pulley 25 is fixed to one end portion of a shaft 27 rotatably supported on a distal end portion of the support plate 22, and a rotary pulley 28 having a non-slip member wound thereon is fixed to another end portion of the shaft 27 opposite from the one end portion. The rotary pulley 28 is provided in such a manner that its outer peripheral surface abuts against the left lower end of a left flange of the bobbin 19. Thus, the bobbin 19 rotates as the rotary pulley 28 rotates by being driven by the drive motor 24 via the driving pulley 23 and the driven pulley 25.
Further, a guide member 29 for guiding the sewing material A paid out from the bobbin 19 is provided underneath the bobbin 19. The guide member 29 is fixed to a pair of guide bases 30 that are disposed on the two support members 20 and extending in the vertical direction. Further, two guide rods 31 and 32 are provided on an upper end portion and a substantially middle portion of the guide member 29 and extend in a left-right direction of FIG. 4 with a gap between the guide rods 31 and 32 and the rear surface of the guide member 29. The sewing material A paid out from the bobbin 19 is guided through the gap between the guide rods 31 and 32 and the rear surface of the guide member 29 toward a lower portion of the sewing machine.
A rod 33 extending in the left-right direction of FIG. 4 is provided underneath the guide member 29, and the rod 33 is fixed at its opposite ends to lower end portions of a pair of left and right pivot arms 34 and 35. The pivot arms 34 and 35 are pivotably supported on the left and right guide bases 30, respectively. A detector for detecting pivoting movement of the left pivot arm 34 is provided on the left guide base 20, and a timer 36 for controlling a driving operation of the drive motor 24 is provided on the left support member 20. As the pivot arm 34 is pivoted in response to sewing of the sewing material A onto the original fabric N, the drive motor 24 is driven for a predetermined time set by the timer 36. Namely, the pivot arm 34 has a switch function for starting the driving operation of the drive motor 24.
A mounting plate 37 of a substantially U shape is fixed to the front surface of the guide member 29, and a guide collar 38 is fixed to a middle region of a lower end portion of the mounting plate 37. Further, as shown in FIG. 5, a first holder 40 is fixed to the front surface of the machine head H via a first bracket 39 extending toward the front of the sewing machine. A flexible tube 41 for passage therethrough of the sewing material A is fixed at one end to the first holder 40 and fixed at the other end to a second holder 43 supported on a holder arm 42 extending from the rotary member 15 as shown in FIG. 4. With such arrangements, the sewing material A directed to the guide member 29 is abutted against the back side of the rod 30, then passed through the guide collar 38, tube 41 and guide 18 of the guide lever 17, and then directed to the needle drop position of the sewing needle 14.
Further, a cutting device C for cutting the sewing material A is disposed rightwardly and downwardly of the machine head H provided on the front surface of the machine frame 1, as shown in FIG. 4. The cutting device C may be any one of the conventionally-known cutting devices including the one disclosed in the aforementioned relevant patent literature, and thus, a description about a construction of the cutting device C is omitted here.
In the instant embodiment of the sewing machine of the invention, a pulling device (pulling member) 44 is disposed in front of the machine head H, and this pulling device (pulling member) 44 is capable of adjusting a length of the sewing material A to be directed through the guide (guide device) 18 to the needle drop position of the sewing needle 14 by pulling the sewing material A after the cutting operation, by the cutting device C, of the sewing material A. A construction of the pulling device 44 will be described below with reference to FIGS. 6 to 8. FIG. 6 is a schematic front view showing an example of the pulling device 44, and FIG. 7 is a schematic plan view explanatory of pulling of the sewing material A and particularly showing a sliding block 50 in a raised position. FIG. 8 is also a schematic plan view explanatory of the pulling of the sewing material A and particularly showing the sliding block 50 in a lowered position. Note that the lower end side in FIGS. 7 and 8 corresponds to the front surface side of the sewing machine.
As shown in FIG. 6, the pulling device 44 has a base 47 of a generally C shape as viewed from the front of the sewing machine, and this base 47 is fixed to the front surface of the machine head H via the first bracket 39, second bracket 45 and third bracket 46. The base 47 has two vertical guide rods 48 fixed thereto at a predetermined distance therebetween. Further, an air cylinder (drive device) 49 is provided on and extends vertically upward from an upper end portion of the base 47. The sliding block (grip device) 50, which is capable of being slidingly guided along the two guide rods 48 and includes a movable piece 53 and a fixed piece 61, is fixed to the distal end of a rod of the air cylinder 49. Namely, in response to driving operation of the air cylinder 49, the sliding block 50 ascends and descends along the guide rods 48 between the raised position indicated by a solid line in FIG. 6 and the lowered position indicated by a phantom line (two-dot-chain line) in FIG. 6.
As shown in plan views of FIGS. 7 and 8, a support member 51 is fixed to the back surface of the sliding block 50, and a sliding rod 52 is provided in the support member 51 in such a manner that it is axially slidable in the longitudinal direction (left-right direction in FIGS. 7 and 8) of the sliding block 50. The movable piece (movable portion) 53 is fixed to a right end portion of the sliding rod 52, and a compression spring 54 is provided on the sliding rod 52 between the movable piece (movable portion) 53 and the support member 51 for normally urging the sliding rod 52 in the rightward direction in the figures. Further, a ball plunger 55 is provided in the sliding block 50 with a ball provided at the distal end thereof and projecting beyond the back surface of the sliding block 50. The movable piece 53 has a recessed portion formed in the front surface thereof for engagement with the ball of the ball plunger 55 projecting beyond the back surface of the sliding block 50. When the sliding rod 52 has slid until the movable piece 53 reaches a position shown in FIG. 7, the ball of the ball plunger 55 engages with the recessed portion in the front surface of the movable piece 53, so that the movable piece 53 is retained in the position shown in FIG. 7 against the biasing force of the compression spring 54.
Further, a roller 56 is fixed to a left end portion of the sliding rod 52, and two (inner and outer) elongated holes 47 a and 47 b of different lengths are formed in different positions (inner and outer positions) of the base 47 as shown in FIG. 6. In the inner elongated hole 47 a of the greater length is provided an upper cam (release device) 57 having a slanting surface 57 a that abuts against the roller 56 to move the sliding rod 52 leftwardly as the sliding block 50 ascends from the lowered position. Further, in the outer elongated hole 47 b of the smaller length is provided a lower can 58 having a slanting surface 58 a that abuts against the roller 56 to move the sliding rod 52 rightwardly as the sliding rod 50 descends from the raised position.
More specifically, the upper and lower cams 57 and 58 have their projections (not shown) slidably engaging with the corresponding elongated holes 47 a and 47 b, and these cams 57 and 58 are fixed at their respective desired positions by means of fixing screws 59 and 60 after having been positioned by the user or human operator at the desired positions along the corresponding elongated holes 47 a and 47 b. Note that the upper and lower cams 57 and 58 are prevented from rotation by the above-mentioned projections engaging with the elongated holes 47 a and 47 b.
Furthermore, the fixed piece (fixed portion) 61 as well as the support member 51 is fixed to the back surface of the sliding block 50. As the sliding rod 52 moves in the rightward direction, the fixed piece 61 sandwiches or grips the sewing material A in conjunction with the movable piece 53 provided on the right end portion of the sliding rod 52. The fixed piece 61 is disposed on a back surface position of the sliding block 50 such that the fixed piece 61 can sandwich or grip a portion of the sewing material A, located above an insertion inlet of the tube 41 in conjunction with the movable piece 53 of the sliding rod 52 as the sliding block 50 descends to the lowered position indicated by the two-dot-chain line in FIG. 6.
Next, a description will be given about how the instant embodiment of the sewing machine constructed in the aforementioned manner performs an operation for sewing the sewing material A onto the original fabric N that is a sewing object, an operation for cutting the sewing material A after completion of the sewing operation and an operation for pulling back the sewing material A after completion of the cutting operation. First, a description will be given about the operation for sewing the sewing material A onto the original fabric N that is a sewing object.
The human operator pays out the sewing material A wound on the bobbin 19 disposed above the machine head H and directs the paid-out sewing material A to the needle drop position of the sewing needle 14 by way of the guide member 29, back side of the rod 33, guide collar 38, tube 41 and guide 18 as set forth above. In this situation, lock switching is performed in the well-known manner through cooperation between the sewing needle 14 and the knot-shown rotary hook by not only controlling movement, in the front-rear and left-right directions (see FIG. 1), of the fabric frame 4, having an original fabric N set thereon, on the basis of predetermined embroidering data but also driving the needle bar vertically. During that time, the presser foot 16 is vertically driven at predetermined timing relative to the vertical up-down movement of the needle bar 14, as well known in the art.
The guide lever 17 is pivotally driven at predetermined timing relative to the vertical up-down movement of the needle bar 14, so that the sewing material A, having been guided to the needle drop position by the guide 18 fixed to the lower end of the guide lever 17, is swung leftward and rightward per vertical reciprocating movement of the needle bar 14 (i.e., per switch). Thus, the sewing material A is sequentially sewn onto the original fabric N through so-called zigzag sewing. During that time, the rotary member 15 is rotationally controlled in accordance with a moving direction of the fabric holder 4 based on predetermined embroidering data so that the guide 18 is positioned ahead in a relative advancing direction of the machine head H based on the movement of the fabric N. In this manner, the sewing material A is appropriately directed to the needle drop position of the sewing needle 14.
As the sewing material A is sequentially sewn onto the original fabric N in the aforementioned manner, the rod 33 is pulled by the sewing material A to be moved toward the front, so that the two pivot arms 34 and 35 are both pivoted in response to the movement of the rod 33. Such pivoting movement of the pivot arm 34 is detected by a detector, on the basis of which the drive motor 24 is driven for a time set by the timer 36 to cause rotation of the bobbin 19, so that the sewing material A is paid out from the bobbin 19. Then, as the sewing material A is further sequentially sewn onto the original fabric N, the two pivot arms 34 and 35 are both pivoted again, in response to which the bobbin 19 is rotated to further pay out the sewing material A. Namely, during the sewing of the sewing material A onto the original fabric N, the bobbin 19 repeats starting and stopping its rotation as the sewing material A is pulled in accordance with a progression of the sewing operation, so that the sewing material A can be appropriately paid out to the needle drop position of the sewing needle 14 in a smooth manner.
Next, a description will be given about the operation for cutting the sewing material A by means of the cutting device C in response to completion of the sewing of the sewing material A onto the original fabric N. Once the sewing of the sewing material A onto the original fabric N is completed in the aforementioned manner, the fabric frame 4 is moved in the front-rear and left-right directions (see FIG. 1) in such a manner that a sewing stop point of the sewing material A sewn onto the original fabric N is moved from the needle drop position of the sewing needle 14 to a predetermined position set near the cutting device C at a given distance from the needle drop position. In response to such movement of the sewing material A, the sewing material A (leading end portion of the sewing material A) is pulled out (i.e., pulled to extend out) from the guide 18 by a length corresponding to an amount of the movement of the sewing material A from the needle drop position to the predetermined position.
After the sewing stop point of the sewing material A is positioned at the predetermined position near the cutting device C, the cutting device C starts moving a cutting member from an evacuation position to a cutting position. During such movement of the cutting member from the evacuation position to the cutting position, the sewing material A is caught by an engaging portion of the cutting member. Then, as the cutting member with the sewing material A caught by the engaging portion is moved from the evacuation position toward the cutting position, a cutting blade of the cutting device C is moved so that the sewing material A is cut through cooperation between the cutting blade and a fixed blade. Upon completion of the cutting of the sewing material A, the cutting device C moves the cutting member from the cutting position back to the evacuation position.
Next, a description will be given about the operation for pulling up (i.e., pulling back) the sewing material A after completion of the cutting operation. In the pulling device 44 constructed in the aforementioned manner, the sliding block 50 is located in the raised position as indicated by the solid line in FIG. 6 during the sewing operation. FIG. 7 shows such a state where the sliding block 50 is located in the raised position. Namely, in this state, the sliding rod 52 has slid to its leftmost position, and the ball of the ball plunger 55 is retained in engagement with the recessed portion formed in the front surface of the movable piece 53.
After the sewing material A is cut by the cutting device C upon completion of the sewing operation, first, the air cylinder 49 is activated or operated in a predetermined direction to start an operation for lowering the sliding block 50 to the lowered position indicated by the two-dot-chain line of FIG. 6, in order to pull back the sewing material A having been paid out more than a length necessary for the sewing material A to be reliably sewn onto the fabric N at the beginning or initial stage of a next sewing operation. Once the descending sliding block 50 reaches or arrives at a position slightly before the above-mentioned lowered position, the roller 56 of the sliding rod 52 abuts against the slanting surface 58 a of the lower cam 58. Then, as the sliding block 50 further descends from the position slightly before the above-mentioned lowered position, the roller 56 is pushed by the slanting surface 58 a of the lower cam 58 so that the sliding rod 52 is slid rightwardly (see FIGS. 6 to 8).
As the sliding rod 52 is slid rightward to some extent in the aforementioned manner, the engagement between the recessed portion of the movable piece 53 and the ball of the ball plunger 55, so that the sliding rod 52 slides, by being urged by the biasing force of the compression spring 54 as well, to a position where a portion of the sewing material A located above the inlet of the tube 41 can be sandwiched or gripped between the movable piece 53 and the fixed piece 61. FIG. 8 shows such a state. In the aforementioned manner, the portion of the sewing material A located above the inlet of the tube 41 can be sandwiched or gripped by the movable piece 53 and the fixed piece 61. Note that, in the instant embodiment, the position of the lower cam 58 in the elongated hole 47 is adjusted in such a manner that the sandwiching of the sewing material A by the movable piece 53 and the fixed piece 61 takes place substantially simultaneously with the arrival, at the lowered position indicated by the two-dot-chain line of FIG. 6, of the sliding block 50 take place at substantially the same time.
Next, the air cylinder 49 is operated in an opposite direction from the aforementioned predetermined direction to start an operation for raising the sliding block 50 from the lowered position indicated by the two-dot-chain line of FIG. 6 back to the predetermined raised position indicated by the solid line of FIG. 6. At that time, the sliding block 50 starts ascending with the sewing material A kept sandwiched between the movable piece 53 and the fixed piece 61 by the biasing force of the compression string 54. In this manner, the sewing material A kept sandwiched between the movable piece 53 and the fixed piece 61 is pulled upward together with the sliding block 50. Then, once the ascending sliding block 50 arrives at a position slightly before the raised position, the roller 56 of the sliding rod 56 abuts against the slanting surface 57 a of the upper cam 57. Then, as the sliding block 50 further ascends from the position slightly before the above-mentioned raised position, the roller 56 is pushed by the slanting surface 57 a of the upper cam 57 so that the sliding rod 52 is slid leftwardly (see FIGS. 6 to 8).
As the sliding rod 52 is slid leftward to some extent in the aforementioned manner, the sewing material A is released from the sandwiching or gripping between the movable piece 53 and the fixed piece 61, upon which the pulling-up of the sewing material A is terminated. Then, as the sliding block 50 further ascends, the sliding rod 52 further slides leftward, so that, by the time the sliding block 50 reaches the raised position, the recessed portion of the movable piece 53 has returned back to the position where it engages with the ball of the ball plunger 55.
As noted above, the pulling-up of the sewing material A is carried out in response to the air cylinder 49 being operated to cause one vertical reciprocating movement of the sliding block 50. Namely, the sewing material A is pulled upward in response to the sliding block 50 being first moved to the lowered position and then moved back to the raised position. In this way, the length of the leading end portion of the sewing material A, having been pulled to extend out from the guide 18 more than necessary at the time of the cutting operation by the cutting device C, can be reduced to a length necessary for the sewing material A to be reliably sewn onto the original fabric N at the initial phase of a next sewing operation.
In the illustrated example of FIG. 6, the upper cam 57 is fixed at a position that can maximize the pull-up (i.e., pull-back) amount of the sewing material A. Note, however, the position at which the upper cam 57 is fixed can be changed to any desired position in the elongated hole 47 a formed in the base 47. If the upper cam 57 is fixed at a lower position than in the illustrated example of FIG. 6, the timing at which the sewing material A is released from the sandwiching between the movable piece 53 and the fixed piece 61 is made earlier than in the illustrated example of FIG. 6, and thus, the pull-up amount of the sewing material A can be reduced. Namely, the pull-up amount of the sewing material A can be changed in response to a change in the fixed position of the upper cam 57 in the elongated hole 47 a formed in the base 47.
According to the preferred embodiment of the sewing machine, as set forth above, the length of the sewing material A, whose leading end portion has been pulled to extend out more than necessary at the time of the cutting operation by the cutting device C, is pulled back by the pulling device (pulling member) 44 and thus can be reduced to the length necessary for the sewing material A to be reliably sewn onto the original fabric at the initial stage of the next sewing operation. In this way, the human operator can minimize an unsewn portion, located ahead of a next sewing start point, of the sewing material A; namely, the human operator can minimize a wasted portion of the sewing material A.
Further, the above-described pulling device 44 is constructed to adjust as desired the pull-up amount of the sewing material A by changing the position of the upper cam 57. Thus, the human operator can readily adjust the length of the leading end portion of the sewing material A, which is to be pulled to extend out from the guide 18, to a desired length depending on the types of the sewing material A and sewing object (original fabric N), which should prove to be very convenient.
Although the preferred embodiment has been described above with reference to the accompanying drawings, it should be appreciated that various modifications are also possible. For example, whereas the preferred embodiment has been described above in relation to the pulling device 44 constructed to pull up the sewing material A by ascending the sliding block 50, the present invention is not so limited, and the pulling device 44 may be constructed in any other manner as long as it can adjust, into a shorter length, the length of the leading end portion of the sewing material A which is to be pulled to extend out from the guide 18 for being reliably sewn onto the original fabric at the initial phase of a next sewing operation.
This application is based on, and claims priority to, JP PA 2011-278225 filed on 20 Dec. 2011. The disclosure of the priority application, in its entirety, including the drawings, claims, and the specification thereof, is incorporated herein by reference.

Claims

1. A sewing machine comprising:

a sewing needle mounted to a lower end portion of a vertically-driven needle bar;

a guide device for guiding an elongated sewing material to a needle drop position of the sewing needle in response to a sewing operation for sewing the sewing material onto a sewing object;

a cutting device for cutting the sewing material after moving the sewing object, having the sewing material sewn thereon through lock stitching, so that a sewing end point of the sewing material is moved from the needle drop position to be located at a predetermined position away from the needle drop position and then pulling the sewing material out from the guide device; and

a pulling device for pulling back the sewing material, whose leading end portion has been pulled out from said guide device, after the cutting by said cutting device, and thereby reducing a length of the leading end portion of the sewing material extending out from said guide device.

2. The sewing machine as claimed in claim 1, wherein said pulling device includes a grip device for gripping the sewing material, and a drive device for moving the grip device, and

wherein said pulling device pulls back the sewing material, whose leading end portion has been pulled out from said guide device at a time of the cutting by said cutting device, by said drive device moving said grip device with the sewing material gripped thereby.

3. The sewing machine as claimed in claim 2, wherein said pulling device further includes a release device for releasing the sewing material from gripping by said grip device, timing for releasing the sewing material being changeable, and

wherein a length by which the sewing material, whose leading end portion has been pulled out from said guide device, is to be pulled back is adjustable in accordance with a change in the timing for releasing the sewing material.

4. The sewing machine as claimed in claim 2, wherein said grip device includes a fixed portion fixedly mounted to a body of said grip device, and a movable portion movably mounted to the body of said grip device, and

wherein, in response to movement in one direction, by said drive device, of said grip device, the movable portion is moved so that the sewing material is gripped between the movable portion and the fixed portion, and, in response to movement in an opposite direction from the one direction, by said drive device, of said grip device, the sewing material gripped between the movable portion and the fixed portion is pulled back in an opposite direction from the direction the sewing material was pulled out from said guide device after the cutting by said cutting device.