JP4371928B2 - Sewing machine looper drive - Google Patents

Description

  The present invention relates to a looper driving device for a sewing machine that operates in synchronization with the vertical movement of a needle, such as a double chain stitch sewing machine or a decorative sewing machine.

Conventionally, as this type of sewing machine looper driving device, there are those shown in FIGS. 11 to 15 (see, for example, Patent Documents 1 and 2). In this case, as shown in FIGS. 11 and 12, the unidirectional rotational motion of the spherical crank portion 43a eccentric to the axis of the main shaft 43 that rotates in synchronization with the vertical movement of the sewing needle 40 is applied to the looper rod 45 and the looper crank. It is converted into a swinging motion of the looper swinging shaft 46 and the swinging arm 47 attached to the looper swinging shaft 46 via 44. The cylindrical portion 47a at the tip of the swing arm 47 is sandwiched between the left and right holders 48 and 49 on both sides of the cylindrical portion 47a at the tip of the swing arm 47 via washers 56 and 57. Both holders 48 and 49 are loopers. The rod 42 is inserted and fixed. Then, the swinging motion of the swinging arm 47 is converted from the cylindrical portion 47 a at the tip of the swinging arm 47 into a reciprocating motion in the axial direction of the looper bar 42 via the left and right holders 48 and 49. Along with this, the looper 41 attached to one end of the looper bar 42 via the looper base 41 a reciprocates in the axial direction of the looper bar 42.

  On the other hand, as shown in FIG. 13, the one-way rotational motion of the eccentric 53 fixed to the main shaft 43 is converted into the back-and-forth swing motion of the looper bar guide 50 via the connecting rod 52. The looper bar guide 50 is provided with a long hole 50a. The looper bar guide 50 and the looper bar 42 are connected to each other by the square piece 51 inserted into the long hole 50a and the left side holder 48 that holds the square piece 51 and is fixed to the looper bar 42. ing. The distal end of the connecting rod 52 is connected to the boss portion 54 of the looper bar guide 50. Accordingly, the looper 41 attached to one end of the looper bar 42 with the shaft center removed via the looper base 41 a performs a swinging motion around the axis of the looper bar 42.

  In the configuration described above, the looper 41 performs an elliptical orbital motion as indicated by symbol A in FIG. 11 by a combined motion of the reciprocating motion of the looper rod 42 in the axial direction and the longitudinal swing motion around the axis. A seam such as a double chain stitch is formed in cooperation with the sewing needle 40 that moves up and down.

JP 2003-53078 A Japanese Patent Laid-Open No. 2003-199987

  In the above-described conventional looper driving device, when the looper rod 42 reciprocates in the axial direction, the cylindrical portion 47a at the tip of the swing arm 47 alternately presses the left and right holders 48 and 49, and the length of the looper rod guide 50 is increased. As the square piece 51 slides along the hole 50a, the looper bar 42 is guided straight in the axial direction. On the other hand, the looper bar 42 needs to swing back and forth together with the looper bar guide 50, and the square piece 51 restrains the relative rotation of the looper bar 42 with respect to the looper bar guide 50, and the looper bar guide 50 swings back and forth. It also serves to transmit to the bar 42.

  Accordingly, the sliding of the square piece 51 for guiding the reciprocating motion of the looper bar 42 in the axial direction is caused by alternating pressing of the looper bar guide 50 against the front and rear side walls in the long hole 50a by the back and forth swing. In particular, in a sewing machine designed to increase the sewing speed, there is a problem that both sliding surfaces wear out early, and this wear causes a gap between the sliding surfaces. If the gap is generated, the movement locus of the looper 41 is shifted, the synchronization between the looper 41 and the vertical movement of the sewing machine needle 40 is lost, and this causes a sewing failure such as stitch skipping, which increases the sewing speed. It is a big obstacle to plan.

  Therefore, in the prior art, as shown in FIG. 15, the square piece 51 and the long hole 50 a are formed in a tapered shape having a V-shaped cross section so as to be taper-fitted to each other, and a fixing rod 51 a is formed from the lower end surface of the square piece 51. A fixing method is employed in which the fixing rod 51a is protruded downward, the fixing rod 51a is inserted into the left holder 48, and fixed from the side surface of the holder 48 with a set screw 55. When a malfunction occurs due to wear of the sliding surface, the set screw 55 is loosened to release the fixation of the square piece 51, and the square piece 51 is pushed down by the amount of wear of the sliding surface to remove the gap between the sliding surfaces. The proper sliding state is adjusted, and then the set screw 55 is retightened to re-fix the square piece 51.

  However, in this case, there is a processing problem that a great deal of labor is required to taper the sliding surfaces of the square piece 51 and the long hole 50a, and the adjustment of the square piece 51 for optimizing the sliding state is very much. There was a problem that it was awkward and difficult and required skill.

  The present invention has been made to solve the above-described problems. The object of the present invention is to provide a conventional looper driving device for a sewing machine as described above in which a pair of left and right first and second holders are provided with the conventional one. By improving the structure to have a square piece function, even if the looper bar guide wears during high-speed operation, the adjustment to the proper sliding state is simplified, the looper bar guide is easily processed, It is an object of the present invention to provide a sewing machine looper drive device which can reduce the number of frames and thereby reduce the number of assembling steps and the number of members.

In order to achieve the above object, a looper driving device for a sewing machine according to the present invention includes a looper rod supported on a sewing machine body so as to be reciprocable in an axial direction and swingable about an axis, and a main shaft of the sewing machine. A swing arm that swings left and right around the looper swinging axis in conjunction with rotation, and a pair of left and right first and second holders fixed on the looper bar so as to slidably hold the tip of the swing arm And a looper bar guide supported so as to be able to swing back and forth around the axis of the looper bar and driving the looper bar to swing around the axis in conjunction with rotation of the main shaft, A looper attached to one end of the looper rod is moved into a predetermined elliptical orbit by a combined motion of a reciprocating motion in the axial direction by the left and right swing of the swing arm and a back-and-forth swing around the axis by the looper rod guide. Misashi made the movement of In the looper driving device,
The looper bar guide is provided with a pair of front and rear first and second sliding surfaces parallel to the axial direction of the looper bar, and the first holder has either the first sliding surface or the second sliding surface. A first sliding portion having a sliding surface that slidably contacts with the sliding surface of the first sliding surface, and the second holder has a sliding surface that is either the first sliding surface or the second sliding surface. A feature is that a second sliding portion having a sliding surface that slidably contacts the surface is provided.

  As a preferred aspect, the looper driving device for a sewing machine according to the present invention is configured such that the first and second sliding surfaces of the looper bar guide are formed on the outer front and rear surfaces of the looper bar guide, or the looper bar guide is provided. It can provide in the front-and-back opposing wall surface in the long hole provided in.

  The first and second holders guide the reciprocating motion of the looper rod in the axial direction by sliding the sliding surfaces of the first and second sliding portions on the pair of front and rear first and second sliding surfaces of the looper rod guide. Demonstrate the function. Further, the first and second sliding portions of the first and second holders restrain the relative rotation of the looper bar with respect to the looper bar guide by always contacting the pair of front and rear first and second sliding surfaces of the looper bar guide, The function of transmitting the looper bar guide back and forth to the looper bar is demonstrated. That is, the first and second holders have the function of a conventional square piece in addition to the original function of holding the tip of the swing arm so as to be slidable on the looper bar. Therefore, the conventional square pieces can be omitted, and the number of assembly steps and the number of members can be reduced accordingly.

  If there is a gap between the first and second sliding surfaces of the looper bar guide and the first and second sliding surfaces of the first and second holders due to wear, remove at least one of the first and second holders from the looper bar. The first and second holders are rotated around the axis of the looper bar so that the sliding surface of the holder comes into contact with the sliding surface of the looper bar guide. Since the holder can be adjusted to an appropriate sliding state by re-fixing it to the looper bar, the adjustment work can be performed easily and quickly.

  In this way, the looper bar guide is processed into a simple shape in which the first and second sliding surfaces parallel to the axis of the looper bar are provided at the front and rear, so that both the first and second holders and the looper bar guide can be processed. Even if wear occurs between the sliding surfaces, it can be easily adjusted to the proper sliding state, so the looper rod guide does not require a long and troublesome tapered long hole processing as before, and the looper rod The guide can be easily processed.

  A preferred embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view of a looper driving device for a sewing machine according to an embodiment of the present invention, FIG. 2 is a front view of the looper driving device of FIG. 1, FIG. 3 is a longitudinal front view of the looper driving device of FIG. 1 is a longitudinal side view of the looper driving device of FIG. 1, FIG. 5 is a sectional view taken along line BB in FIG. 2, and FIG. 6 is a perspective view of the main part including the looper bar guide and first and second holders of the looper driving device of FIG. FIG. 7 is a perspective view of the first and second holders of the looper driving device of FIG.

  As shown in FIGS. 1 to 3, the looper 1 to be driven is attached to one end of the looper bar 2 with the axis of the looper bar 2 removed via the looper base 3. The looper bar 2 is arranged on the left and right bushes which are arranged substantially perpendicular to the vertical movement direction of the sewing needle 4 and the feed direction F of the fabric and parallel to the main shaft 5 and fixed to a part 6 of the sewing machine body (not shown). 7 and 8 are supported by the left bush 7 so as to be slidable in the axial direction and swingable about the axis. Each of the left and right bushes 7 and 8 is formed in a stepped shape having small diameter portions 7a and 8a at one end.

  As shown in FIG. 6, the looper bar guide 9 is a gate in which the upper end edges of a pair of left and right support end plates 9a, 9b facing each other are connected to each other by a connecting plate 9c having a predetermined front-rear width and long in the axial direction (left-right direction). The support end plates 9a and 9b are provided with support holes 10 and 11, respectively. As shown in FIG. 3, the looper bar guide 9 is arranged around the axis of the looper bar 2 by inserting the left and right support holes 10 and 11 into the small diameter portions 7 a and 8 a of the bushes 7 and 8 so as to be rotatable. It is supported so that it can swing back and forth. As shown in FIG. 6, the front and rear outer end surfaces of the connecting plate 9c of the looper bar guide 9 are vertically slidable with sliding surfaces 14a and 15a of a pair of left and right first and second holders 12 and 13, which will be described later. A pair of front and rear first and second sliding surfaces 16 and 17 are formed in parallel to the axial direction of the looper bar 2.

  Next, a mechanism unit for driving the looper 1 and the looper rod 2 will be described.

  First, the drive mechanism part of the looper rod 2 in the axial direction will be described with reference to FIGS. A spherical eccentric portion 5 a provided on the main shaft 5 and a looper crank 19 whose base end is fixed to the looper swing shaft 18 are connected by a looper rod 20. The looper swing shaft 18 extends in a direction perpendicular to the main shaft 5. The drive mechanism transmits the swinging motion about the axis to the looper swing shaft 18 by the rotation of the main shaft 5. The base end of the swing arm 21 is fixed to the looper swing shaft 18, and the distal end portion 21 a of the swing arm 21 has a cylindrical bifurcated portion. On the other hand, a pair of left and right first and second holders 12 and 13 are fastened and fixed to the looper rod 2 with screws 22 and 23, and the first and second holders 12 and 13 are pivoted through left and right washers 24 and 25, respectively. The tip portion 21a of 21 is sandwiched so that there is no gap. The left and right washers 24 and 25 are rotatably inserted into the looper bar 2.

  In this case, when the swing arm 21 swings left and right around the looper swing shaft 18 along with the swing motion of the looper swing shaft 18, the distal end portion 21 a of the swing arm 21 presses the left and right washers 24 and 25. As a result, the swinging motion of the swinging arm 21 is transmitted to the left and right holders 12 and 13 and converted into the reciprocating motion of the looper bar 2 in the axial direction.

  Next, a drive mechanism for swinging the looper rod 2 back and forth around the axis will be described with reference to FIG. An eccentric ring 26 is fixed to the main shaft 5, and a base end of a connecting rod 27 is rotatably connected to the eccentric ring 26, and a distal end of the connecting rod 27 is rearward from a part of the rear side surface of the connecting plate 9 c of the looper bar guide 9. It is pivotally connected to a boss 9d projecting from the top. Thus, the drive mechanism is configured to transmit the swinging motion around the axis of the looper bar 2 to the looper bar guide 9 through the eccentric ring 26 and the connecting rod 27 by the rotation of the main shaft 5.

  In the looper driving device having the above-described configuration, the present invention has a function of guiding the reciprocating motion of the looper rod 2 in the axial direction, and a function of transmitting the swinging motion of the looper rod guide 9 to the swinging motion around the axis of the looper rod 2. Is characterized in that it can be performed only between the first and second holders 12 and 13 and the looper bar guide 9.

For this purpose, the first and second holders 12 and 13 come into contact with the second sliding surface 17 of the looper bar guide 9 from the rear end of the upper end of the left first holder 12 as shown in FIGS. The first sliding portion 14 having the vertical sliding surface 14 a that slides in contact with the first sliding surface 16 of the looper bar guide 9 slides from the front end of the upper end of the second holder 13 on the right side. The second sliding portions 15 each having a vertical sliding surface 15a are integrally formed so as to rise upward.
Thus, when the looper rod 2 is reciprocated in the axial direction, the first and second sliding surfaces 14a and 15a of the first and second holders 12 and 13 accompanying the looper rod 2 are the first and second sliding surfaces of the looper rod guide 2. The looper bar 2 is guided straight in the axial direction by sliding in contact with 16 and 17 respectively. On the other hand, the looper bar 2 needs to swing back and forth around the axis along with the looper bar guide 9, and the first and second holders 12 and 13 connect the first sliding part 14 and the second sliding part 15 to the looper bar. By always abutting against the second sliding surface 17 and the first sliding surface 16 of the guide 9, the relative rotation of the looper rod 2 with respect to the looper rod guide 9 is restrained, and the swing of the looper rod guide 9 is controlled by the looper rod. Also acts to convey to 2.

  When assembling the first and second holders 12 and 13, the first and second holders 12 and 13 and the looper bar guide 9 are inserted into the looper bar 2. First, the second holder 13 is screwed into a predetermined position of the looper bar 2. 23, the sliding surface 15a is brought into contact with the first sliding surface 16 on the front side of the looper bar guide 9, and the other left first holder 12 is then rotated around the axis of the looper bar 2. Then, the sliding surface 14 a is brought into contact with the second sliding surface 17 on the rear side of the looper bar guide 2, and the holder 12 is fastened and fixed to the looper bar 2 with a screw 22. Accordingly, the first and second holders 12 and 13 can be easily and reliably assembled to the looper bar 2 and the looper bar guide 9.

  In the looper driving device configured as described above, when the main shaft 5 is rotated by the drive source of the sewing machine, the looper bar 2 performs reciprocating motion in the axial direction and simultaneously swinging back and forth around the axis. As a result, the looper 1 attached to one end of the looper bar 2 with its axis removed is moved in an elliptical orbit having a long axis in the axial direction of the looper bar 2 as indicated by reference numeral A in FIG. . The movement of the looper 1 and the vertical movement of the sewing needle 4 are performed in synchronism, and the looper 1 and the sewing needle 4 are engaged with each other, thereby forming a double chain stitch.

  According to the looper driving device configured as described above, the first and second holders 12 and 13 have the function of the conventional square piece, that is, the looper bar 2 in addition to the original function of slidably holding the tip of the swing arm 21. Both the function of guiding the reciprocating movement of the looper rod 2 and the function of restricting the relative rotation of the looper rod 2 with respect to the looper rod guide 9 and transmitting the forward / backward swing of the looper rod guide 9 to the looper rod 2. The pieces can be omitted, and the number of assembling steps and the number of members can be reduced accordingly.

Further, the looper bar guide 9 is simply provided with the first and second sliding surfaces 16 and 17 at the front and rear, so that it is not necessary to process a long hole with a taper which is troublesome as in the prior art. Can do.
If there is a gap between the sliding surfaces of the looper bar guide 9 and the first and second holders 12 and 13 due to wear, the tightening and fixing state of the first holder 12 to the looper bar 2 with the screw 22 is loosened, and the second holder 13 with the sliding surface 15 a in contact with the first sliding surface 16 of the looper bar guide 9, the first holder 12 is rotated about the axis of the looper bar 2 to slide the first holder 12. 14a is brought into contact with the second sliding surface 17 of the looper bar guide 9, the screw 22 is retightened, and the first holder 12 is re-fixed to the looper bar 2, so that the proper sliding state can be adjusted. Work can be done easily and quickly.

  In the above embodiment, the first and second sliding surfaces 16 and 17 are formed on the front and rear outer surfaces of the looper bar guide 9, but instead of this, as shown in FIG. A long hole 28 is provided in the axial direction, and first and second sliding surfaces 16 and 17 are provided on front and rear facing wall surfaces 28a and 28b that are parallel to and perpendicular to the axis of the looper rod 2 in the long hole 28. May be. In this case, the sliding surface 15 a of the second sliding portion 15 of the second holder 13 is in contact with the first sliding surface 16 on the front side in the long hole 28, and the sliding surface of the first sliding portion 14 of the first holder 12. 14a is set to slide in contact with the second sliding surface 17 on the rear side.

  In the above embodiment, the sliding surface 14a of the first sliding portion 14 raised from the rear end of the upper end of the first holder 12 is brought into contact with the second sliding surface 17 of the looper bar guide 9, and the second The sliding surface 15a of the second sliding portion 15 raised from the front end of the upper end of the holder 13 is configured to come into contact with the first sliding surface 16 of the looper bar guide 9, but on the contrary, The first sliding portion 14 is raised from the front end of the upper end of the first holder 12, and the sliding surface 14 a of the first sliding portion 14 abuts on the first sliding surface 16 of the looper bar guide 9, The second sliding portion 15 is raised from the rear end of the upper end of the two holders 13, and the sliding surface 15a of the second sliding portion 15 is brought into contact with the second sliding surface 17 of the looper bar guide 9. You can also

  In the above embodiment, when the first and second holders 12 and 13 are fastened and fixed to the looper bar 2 with screws 22 and 23, as shown in FIGS. A split-type shaft coupling portion 29 whose shaft diameter can be adjusted by opening and closing the slit portion 29a is provided, and the shaft coupling portion 29 is coupled to the looper rod 2 and fixed by tightening the screws 22. On the other hand, a screw hole 30 is provided in a part of the circumference of the cylindrical portion 13a of the right second holder 13 inserted through the looper rod 2, and a screw 23 is tightened in the screw hole 30 so that the tip of the screw 23 is a hollow looper rod. 2 is fixed by engaging with a hole 31 provided in a predetermined position. On the other hand, as shown in FIG. 9, each of the first and second holders 12 and 13 is provided with a shaft coupling portion 29 having a slit portion 29a, as in the case of the first holder 12 of the above-described embodiment. It is also possible to provide each shaft coupling portion 29 with the looper rod 2 and tighten the screws 22 and 23 to fix them.

  Further, in the above embodiment, as shown in FIG. 2, the looper bar 2 is cantilevered only on the left bush 7 so as to be slidable in the axial direction and rotatable about the axis. The end portion 2a on the end side is inserted into and fixed to the second holder 13 on the right side, and the right support end plate 9b of the looper bar guide 9 is rotatably supported on the right bush 8; As shown in FIG. 2, the looper bar 2 can be supported at both ends by the left and right bushes 7 and 8.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sewing machine looper drive device according to an embodiment of the present invention. It is a front view of the looper drive device of FIG. It is a vertical front view of the looper drive device of FIG. It is a vertical side view of the looper drive device of FIG. It is the BB sectional view taken on the line in FIG. FIG. 2 is a perspective view of a main part including a looper bar guide and first and second holders of the looper driving device of FIG. 1. It is a perspective view of the 1st and 2nd holder of the looper drive device of FIG. It is a perspective view of the principal part which shows another Example corresponding to FIG. It is sectional drawing which shows another Example corresponding to FIG. It is a front view which shows other Example corresponding to FIG. It is a perspective view which shows the looper drive device of the conventional sewing machine corresponding to FIG. It is a longitudinal front view which shows the looper drive device of the conventional sewing machine corresponding to FIG. It is a vertical side view which shows the looper drive device of the conventional sewing machine corresponding to FIG. It is a perspective view of the left and right holders and the swing arm of the looper drive device of the conventional sewing machine. It is a side view of a looper bar guide, a square piece, and a left holder of a looper drive device of a conventional sewing machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Looper 2 Looper bar 5 Main shaft 6 Part of sewing machine main body 9 Looper bar guide 12 First holder 13 Second holder 14 First sliding part 14a Sliding surface of first sliding part 15 Second sliding part 15a Second Sliding surface of sliding portion 16 First sliding surface 17 Second sliding surface 18 Looper swing shaft 21 Swing arm 22, 23 Screw 28 Long hole 28a, 28b Front and rear facing walls

Claims (3)

A looper bar supported on the sewing machine body so as to be capable of reciprocating in the axial direction and swingable about the axis;
A swinging arm that swings left and right around the looper swinging axis in conjunction with the rotation of the main shaft of the sewing machine;
A pair of left and right first and second holders fixed on the looper rod so as to slidably hold the tip of the swinging arm;
A looper bar guide supported so as to be able to swing back and forth around the axis of the looper bar and driving the looper bar to swing around the axis in conjunction with rotation of the main shaft;
A looper attached to one end of the looper bar is obtained by a combined movement of the reciprocating movement of the looper bar in the axial direction by swinging the swinging arm left and right and swinging back and forth around the axis by the looper bar guide. In the sewing machine looper drive device configured to move in a predetermined elliptical orbit,
The looper bar guide is provided with a pair of front and rear first and second sliding surfaces parallel to the axial direction of the looper bar, and the first holder has either the first sliding surface or the second sliding surface. A first sliding portion having a sliding surface that slidably contacts with the sliding surface of the first sliding surface, and the second holder has a sliding surface that is either the first sliding surface or the second sliding surface. A looper driving device for a sewing machine, comprising a second sliding portion having a sliding surface slidably contacting the surface.   The looper drive device for a sewing machine according to claim 1, wherein the first and second sliding surfaces of the looper bar guide are formed on front and rear outer surfaces of the looper bar guide. The looper drive device according to claim 1, wherein the first and second sliding surfaces of the looper bar guide are provided on front and rear wall surfaces in a long hole provided in the looper bar guide.

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