JP2006095271A - Driving force transmission device for twin-needle sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving force transmission device for a twin-needle sewing machine by which a needle bar falling-off accident upon switching operation to discontinue vertical motion of the needle bar can be surely prevented as well as fracture of a needle bar and a throat plate. <P>SOLUTION: When vertical motion of a needle bar 7L is discontinued halfway through sewing, and when a main shaft is rotatively driven in high speed upon switching operation, even if projecting timing of a second engaging piece 41L to engage the second engaging piece 41L with an upper engaging recess part 7a by spring force is delayed and the upper engaging recess part 7a passes under the second engaging piece 41L to fall off the needle bar 7L from a needle bar support frame 5, the needle bar 7L is prevented from falling off the needle bar support frame 5 because a washer 22L fixed to the upper end of the needle bar 7L abuts on an upper frame 5a of the needle bar support frame 5. Furthermore, a distance L between upper and lower engaging recess parts 7a, 7b is set larger than an operation stroke SS of the needle bar 7L to surely prevent fracture of the needle bar 7L and the throat plate 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to one in which one of the two needles which is not used is locked and held at its uppermost position so that one stitch formation can be temporarily interrupted. .

  Conventionally, when a double stitch is formed around a pocket fabric such as jeans with a two-needle feed sewing machine or the like, the inner stitch of the double stitch is formed at the corner of the pocket fabric. After the needle bar is temporarily held at the uppermost position and paused, and only the outer seam is formed continuously, the needle bar that has been paused is continued along with the end of sewing at the corner. The double stitches are formed on the outer periphery of the pocket fabric.

  For example, in the needle bar motion control device for a sewing machine disclosed in Patent Document 1, a pair of upper and lower locking recesses are formed in each of a pair of left and right needle bars, and a lower engagement of the needle bar and these locking recesses is provided. A first locking piece that can be connected to the needle bar clamp and the needle bar that is moved up and down in conjunction with the sewing machine main shaft and the upper locking recess to fit the needle bar to the uppermost position. A second locking piece to be paused at the position, a long operating lever is interposed between the locking recesses in the vertical direction, and the operating lever is rotated by the switching means so that the first and second locking It is configured so that it can be engaged and disengaged with respect to the locking recess of the piece, and the vertical movement of either one of the left and right needle bars with respect to the sewing machine main shaft can be stopped at the uppermost position.

That is, when the needle bar is stopped at its uppermost position without moving up and down, the first locking piece is retracted to the inside of the needle bar holder via the switching means at the uppermost position of the needle bar, and the first bar The locking piece is detached from the lower locking recess. At this time, the operating lever is in a freely rotating state, the second locking piece is fitted into the upper locking recess, and the needle bar is rested at its uppermost position.
Japanese Utility Model Publication No. 55-34938 (Pages 2 and 3, FIGS. 1 to 3)

  In the needle bar movement control device for a sewing machine described in Patent Document 1 described above, an operator who is skilled in double stitching works by appropriately operating the switching means when sewing the corner portion, so that one needle as described above is used. The vertical movement of the bar is stopped at its uppermost position. By the way, when the operator operates the switching means during high-speed rotation, since the moving speed of the needle bar is fast, the second locking piece is engaged with the upper locking recess by the spring force of the second coil spring. When the engagement timing is delayed (response delay) and the upper locking recess passes through the second locking piece, the needle bar is not locked by any locking recess and the needle bar falls off. In other words, there is a problem that the needle bar comes off.

  Further, when the needle bar is dropped as described above and the needle bar is pulled out, the first locking piece is engaged with the upper locking recess during the vertical driving of the needle bar. The needle bar is driven up and down at a height position lowered by the operating stroke, and each time the needle bar is lowered, the lower end of the needle bar repeatedly and strongly collides with the needle plate, so the needle bar is bent. There are problems such as occurrence and breakage of the needle plate.

  A driving force transmission device for a two-needle sewing machine according to claim 1 is a two-needle sewing machine that individually transmits a driving force of a main shaft to two parallel needle bars supported by a needle bar support frame so as to be movable up and down. In the driving force transmission device, upper and lower locking recesses formed at predetermined intervals in the upper and lower sides of each needle bar, and vertical grooves formed in each needle bar over the upper and lower locking recesses. An operating lever that is movably mounted and is pivotally supported by a pivot pin that is parallel to the main axis in the middle of its length, and can protrude to selectively close the upper and lower locking recesses at both upper and lower ends. An operating lever having an abutment surface, and a needle bar holding mechanism connected to a needle bar crank connected to the main shaft, the movable first locking being engageable with a lower locking recess of each needle bar A first biasing member that biases the first locking piece toward the engagement side, and a lock mechanism that locks the first locking piece in the non-engagement position. A needle bar holding mechanism, a second locking piece that can be engaged with the upper locking recess of each needle bar, and a second biasing member that biases the second locking piece toward the engagement side. Disengagement of the first locking piece with respect to the lower locking recess of the needle bar when any of the needle bars is at the upper position of the operating stroke; An operation mechanism for selectively unlocking the lock mechanism and each needle bar from the lower limit position of the operating stroke relative to the needle bar support frame to prevent the needle bar from falling off the needle bar support frame And a locked member that is locked by a locking member provided on the sewing machine frame side when it is slightly lowered, and is provided with a locked member provided on each needle bar.

  When the lock state of the lock mechanism is released by the operation mechanism, the first locking member is engaged with the lower locking recess by the first urging member, so that the operating lever mounted in the longitudinal groove causes the pivot pin to move. Since the upper locking recess is closed by the upper contact surface, the second locking piece mounted on the upper frame of the needle bar support frame does not engage with the upper locking recess. When the main shaft is rotationally driven in this state, the driving force of the main shaft is reciprocally driven up and down by an operating stroke through a needle bar holding mechanism connected to the needle bar crank.

  On the other hand, when one of the needle bars is at the upper position of the operating stroke, and the operation mechanism releases the engagement with the lower locking recess of the first locking piece, the operating lever mounted in the vertical groove Oscillates and closes the lower locking recess with the lower contact surface, so that the second locking piece biased by the second biasing member engages with the upper locking recess. Even if the main shaft is rotationally driven in this state, the driving force of the main shaft is not transmitted to the needle bar from which the engagement of the first locking piece is released, and the needle bar is locked and held at its upper position. It is not driven up and down.

  By the way, when the moving speed of the needle bar is high due to the switching operation at high speed rotation, the second locking piece cannot follow (response delay), and the needle bar is not locked, the first and second locking pieces Since neither of them supports the needle bar, the locked member provided on the needle bar is locked by the locking member provided on the sewing machine frame side even when the needle bar is detached from the needle bar support frame. This prevents the needle bar from falling off.

  A driving force transmission device for a two-needle sewing machine according to a second aspect is the invention according to the first aspect, wherein the locked member is a protruding member that protrudes horizontally from the outer periphery of the needle bar.

  A drive force transmission device for a two-needle sewing machine according to a third aspect is the invention according to the second aspect, wherein the protruding member is fixed to an upper end portion of the needle bar or a vicinity thereof, and the locking member is constituted by a needle bar support frame. It has been done.

  A driving force transmission device for a two-needle sewing machine according to a fourth aspect is the invention according to any one of the first to third aspects, wherein the distance between the upper and lower locking recesses is set larger than the operating stroke of the needle bar. It has been done.

  A driving force transmission device for a two-needle sewing machine according to claim 5 is the invention as set forth in any one of claims 1 to 4, wherein the locked member is locked by the locking member. The locking recess is located above the first locking piece at the upper limit position of the operating stroke.

  According to the first aspect of the present invention, in the driving force transmission device for a two-needle sewing machine that individually transmits the driving force of the main shaft to two parallel needle bars supported by the needle bar support frame so as to be movable up and down, Upper and lower locking recesses formed in the needle bar, an operating lever movably mounted in a longitudinal groove formed in each needle bar across the upper and lower locking recesses, and a first locking piece And a lock mechanism, a needle bar holding mechanism connected to a needle bar crank connected to the main shaft, a second locking piece and a second urging member, and a needle bar mounted on the needle bar support frame Since a locking mechanism, an operation mechanism, and a locked member that is locked by a locking member provided on the sewing machine frame side in order to prevent the needle bar from falling off from the needle bar support frame, Switching operation is performed during high-speed rotation by the operation mechanism, the needle bar moves fast, the second locking piece cannot follow (response delay), and the upper locking recess is downward Even when the needle bar does not lock and support the needle bar when it passes, the needle bar is provided on the needle bar even when the needle bar falls off the needle bar support frame. Since the locked member is locked by the locking member provided on the sewing machine frame side, it is possible to reliably prevent the needle bar from falling off the needle bar support frame.

  According to the invention of claim 2, since the locked member is a protruding member that protrudes horizontally from the outer periphery of the needle bar, the small and inexpensive protruding member is fixed to the needle bar horizontally. It is possible to prevent the rod from falling off. Other effects similar to those of the first aspect are obtained.

  According to the invention of claim 3, since the protruding member is fixed to the upper end portion of the needle bar or the vicinity thereof, and the locking member is constituted by the needle bar support frame, the sewing machine is not provided with a separate locking member. The needle bar support frame can be effectively utilized to function as a locking member, and the protrusion member can be easily attached to the needle bar. Other effects similar to those of the second aspect are achieved.

  According to the invention of claim 4, since the distance between the upper and lower locking recesses is set larger than the operating stroke of the needle bar, the needle bar locked so as not to drop off by the locked member In the case where the lower locking recess and the lower limit position of the operation stroke substantially correspond to each other, the first locking piece and the upper locking recess are Therefore, the collision between the lower end of the needle bar and the needle plate can be prevented, and the needle bar and the needle plate can be reliably prevented from being damaged. Other effects similar to those of any one of claims 1 to 3 are provided.

  According to the invention of claim 5, in a state where the locked member is locked by the locking member, the upper locking recess of each needle bar is above the first locking piece at the upper limit position of the operation stroke. Since the engagement between the first locking piece and the upper locking recess can be reliably avoided during the vertical driving of the needle bar holding mechanism by the driving force of the main shaft, the lower end of the needle bar and the needle plate The needle bar and the needle plate can be reliably prevented from being damaged. Other effects similar to those of any one of claims 1 to 4 can be achieved.

  The driving force transmission device for a two-needle sewing machine in this embodiment can prevent the needle bar from falling off by locking the locked member fixed to the upper end of the needle bar with a locking member provided on the sewing machine frame side. In addition, the distance between the upper and lower engaging recesses is made larger than the operating stroke of the needle bar so that the first locking piece in the needle bar holding mechanism cannot be engaged with the upper engaging recess, and the needle bar and the needle plate It is possible to reliably prevent damage caused by the collision.

  A main shaft 4 is disposed in the left-right direction in the arm portion 2 of the two-needle sewing machine 1 capable of needle feeding, and is pivotally supported at a plurality of locations on the machine frame 2A. In the head portion 3 of the arm portion 2, a substantially U-shaped needle bar support frame 5 is fixed to the left end portion of the left and right swing shaft 6 in a front view, and is known via the swing shaft 6 as is well known. Can swing back and forth (needle feed direction). The upper and lower frames 5a and 5b of the needle bar support frame 5 support the two needle bars 7L and 7R, which are separated from each other by a predetermined distance in the left and right directions, so that the needle bars 7L and 7R can move up and down at the upper and lower parts. The sewing needle 8 is detachably fixed to the lower end of each.

  Next, the driving force transmission device 11 that transmits the driving force of the main shaft 4 to the needle bars 7L and 7R will be described. The driving force transmission device 11 includes upper and lower locking recesses 7a and 7b formed for each needle bar 7L and 7R, operating levers 12L and 12R, needle bar holding mechanisms 13L and 13R, and a needle bar mechanism. Stop mechanisms 14L and 14R, an operation mechanism 15 and the like are provided. Here, the upper and lower locking recesses 7a and 7b, the operating levers 12L and 12R, the needle bar holding mechanisms 13L and 13R, and the needle bar locking mechanisms 14L and 14R are the left and right needle bars 7L and 7R. Since it is configured similarly, the left needle bar 7L will be described.

  Regarding the right needle bar 7R, the same members as those described with respect to the left needle bar 7L are denoted by the same reference numerals, and the description thereof is omitted. However, a mechanism and members related to the left needle bar 7L will be described with reference L, and a mechanism and members related to the right needle bar 7R will be described with reference R.

  The needle bar holder 17 is a block-like member having a pair of left and right through holes 17a into which a pair of parallel left and right needle bars 7L and 7R are fitted in the vertical direction. The needle bar crank 19 is fixed to the end of the main shaft 4 via an eccentric position. Therefore, as the main shaft 4 rotates, the needle bar holder 17 moves up and down via the needle bar crank 19 and the needle bar crank rod 18, and a pair of needle bars 7L and 7R via the lock mechanisms 27L and 27R described later. Are reciprocated up and down by the operating stroke SS (see FIG. 7) synchronously.

  First, the upper and lower locking recesses 7a and 7b formed on the needle bar 7L and the operating lever 12L provided on the needle bar 7L will be described. Although the left needle bar 7L has a cylindrical shape, as shown in FIGS. 3 and 4, a flat portion 7c having a predetermined width chamfered from the upper end portion to the substantially lower end portion is formed. As shown in FIG. 3, an upper locking recess 7 a that is a notch having a circular arc shape when viewed from the side and a lower locking recess 7 b that is rectangular when viewed from the side, are provided in the upper portion of the needle bar 7 L at a predetermined distance L up and down. And are formed respectively.

  In the flat portion 7c of the needle bar 7L, a vertical groove 7d extending in the vertical direction is formed over a predetermined length across the upper locking recess 7a and the lower locking recess 7b. That is, the distance L between the upper and lower locking recesses 7a and 7b is set to be larger than the vertical operation stroke SS of the needle bar 7L (see FIG. 7).

  The actuating lever 12L made of a plate member is movably mounted in a longitudinal groove 7d formed in the needle bar 7L, and can be rotated to the needle bar 7L by a pivot pin 21 parallel to the main shaft 4 in the middle in the length direction. It is pivotally supported by. At both the upper and lower end portions of the operating lever 12L, contact surfaces 12a and 12b are formed that can protrude so as to selectively close the upper and lower locking recesses 7a and 7b.

  A washer 22L (which corresponds to a locked member) that is larger than the outer shape of the needle bar 7L, that is, a protruding member that protrudes horizontally from the outer periphery of the needle bar 7L, is fixed to the upper end of the needle bar 7L with a screw 23L. Yes. Therefore, the needle bar 7L is prevented from dropping downward from the needle bar support frame 5 by the washer 22L.

  Next, the needle bar holding mechanism 13L connected to the needle bar crank 19 connected to the main shaft 4 will be described. The needle bar holding mechanism 13L includes a movable first locking piece 25L that can be engaged with the lower locking recess 7b of the needle bar 7L, and a first coil spring that biases the first locking piece 25L toward the engagement side. 26L (this corresponds to the first urging member) and a lock mechanism 27L that locks the first locking piece 25L in the non-engagement position.

  As shown in FIG. 4, the first locking piece 25 </ b> L has a horizontal columnar shape, and is fitted in a front-rear direction accommodation hole 17 b formed in the needle bar holder 17 so as to be movable back and forth. A horizontal support pin 28L is fixed to the divided cylindrical portion. Therefore, the first locking piece 25L cooperates with the lower locking recess 7b of the pair of upper and lower locking recesses 7a and 7b to connect the needle bar holder 17 and the needle bar 7L to each other. 4 is transmitted to the needle bar 7L via the needle bar holder 17.

  Next, the lock mechanism 27L will be described. The L-shaped swing lever 31L in a side view is pivotally supported by the needle bar holder 17 by a pivot pin 32, and a vertically elongated slot 31a is formed at the lower end thereof. The support pin 28L is inserted in the inside. The first coil spring 26L is housed in a cylindrical recess 17c formed vertically on the upper portion of the needle bar holder 17, and engages with the hook-shaped rear end portion of the swing lever 31L from the lower side. The first locking piece 25L is elastically biased so that the first locking piece 25L is always engaged with the lower locking recess 7b so that 31L is rotated clockwise in FIGS.

  The L-shaped locking lever 33L arranged in the side view in the lower side of the first locking piece 25L is pivotally supported on the needle bar holder 17 by a pivot pin 34L at its base end. Yes. The locking lever 33L is integrally formed with a vertical arm portion 33a that engages with the support pin 28L from the front side and a horizontal arm portion 33c that extends horizontally and to the right, and faces upward toward the rear end portion of the locking lever 33L. The locking hook portion 33b is formed.

  Further, a second compression coil spring 35L is stretched between the lower side of the latching hook portion 33b of the latching lever 33L and the needle bar holder 17, and the latching lever 33L is provided with FIGS. As shown in FIG. 4, clockwise turning power is applied.

  When the swing lever 31L rotates counterclockwise against the spring force of the first compression coil spring 26L by the operation of the operation mechanism 15 described later, the first locking piece 25L moves forward via the support pin 28L. Since it is moved, the locking hook portion 33b is locked in the engaging recess 25a formed in the lower portion of the first locking piece 25L (see FIG. 6-1). As a result, the first locking piece 25L is disengaged from the lower locking recess 7b and locked in the disengaged position.

  The horizontal arm portion 33c of the left locking lever 33L extends to a position approaching the horizontal arm portion 33c of the right locking lever 33R, and can be moved up and down by the needle bar holder 17 at the joint portion of both horizontal arm portions 33c. The lower end of the supported release pin 36 extends so as to abut against the upper surfaces of both horizontal arm portions 33c. The release pin 36 is always subjected to a downward pressing force by a very weak compression coil spring 38 stretched between a washer 37 fixed to the needle bar holder 17.

  Next, the needle bar locking mechanism 14L that locks and holds the needle bar 7L near its uppermost position will be described. The second locking piece 41L is supported by the through hole 5c formed in the upper frame 5a of the needle bar support frame 5 in the front-rear direction so that the second locking piece 41L can move back and forth. 2), the rear end of the compression coil spring 42L is regulated by a closing plate 44 fixed to the upper frame 5a by a screw 43.

  Therefore, the second locking piece 41L is elastically biased so as to be always engaged in the upper locking recess 7a by the spring force of the compression coil spring 42L. That is, when the second locking piece 41L is engaged with the upper locking recess 7a, the needle bar 7L is temporarily locked at a position substantially above its operating stroke SS regardless of the vertical driving of the needle bar holder 17. Hold (see FIGS. 6-1 and 6-2).

  By the way, as described above, when the first locking piece 25L is engaged with the lower locking recess 7b, the lower contact surface 12b of the operating lever 12L is pushed backward as shown in FIG. Since the upper abutment surface 12a protrudes into the upper locking recess 7a, the engagement of the second locking piece 41L with the upper locking recess 7a is reliably prevented, and the first locking piece 25L is 1 compression coil spring 26L is engaged and held in the lower locking recess 7b by the spring force.

On the other hand, as shown in FIG. 6A, when the second locking piece 41L is engaged with the upper locking recess 7a by the spring force of the compression coil spring 42L, the upper contact surface 12a of the operating lever 12L is pushed backward. Since the lower contact surface 12b protrudes into the lower locking recess 7b, the engagement of the first locking piece 25L with the lower locking recess 7b is reliably prevented. In this case, the second locking piece 41L is engaged and held in the upper locking recess 7a by the spring force of the compression coil spring 42L.

  Next, when the needle bar 7L is in the upper position of the operating stroke SS, the first locking piece 25L is disengaged from the lower locking recess 7b of the needle bar 7L and the lock mechanism 27L is unlocked. The operation mechanism 15 for selectively performing will be described.

  A horizontal support recess (not shown) is formed in the upper frame 5a immediately below the needle bar locking mechanism 14L provided on the needle bar support frame 5 described above, and as shown in FIGS. The sliding piece 46 is slidably accommodated therein, and the sliding plate 46 is prevented from being detached by a cover plate 48 fixed to the needle bar support frame 5 with screws 47. An operating protrusion 46 a that protrudes downward is integrally formed at the right end of the sliding piece 46.

  In this case, as shown in FIG. 4, the sliding piece 46 has a driving force transmission position (solid line) corresponding to the release pin 36 based on the operation of switching means (not shown) operated by the operator. ), The left needle bar engagement release position (illustrated by a two-dot chain line on the left side) corresponding to the left swing lever 31L, and the operation protrusion 46a corresponding to the right swing lever 31R. The position is appropriately switched to 3 positions with the right needle bar disengagement position (illustrated by the two-dot chain line on the right side).

  That is, when the operating projection 46a of the sliding piece 46 is switched to the left needle bar engagement release position corresponding to the left swing lever 31L by the operation of the switching means, the needle bar holder 17 is raised to the uppermost position of the operating stroke SS. In this case, since the operating protrusion 46a presses the left swing lever 31L downward, the swing lever 31L rotates counterclockwise, and the first engagement with respect to the lower locking recess 7b by the first compression coil spring 26L. The engagement of the stop piece 25L is released.

  On the other hand, when the operating projection 46a is switched to the driving force transmission position corresponding to the release pin 36 by the operation of the switching means, when the needle bar holder 17 is raised to the uppermost position of the operating stroke SS, the release pin 36 is moved by the operating projection 46a. Since it is pressed downward, the locking lever 33L rotates counterclockwise via the horizontal arm portion 33c.

  As a result, the lock at the disengagement position of the first locking piece 25L by the locking hook portion 33b is released, that is, the lock mechanism 27L is unlocked, and the first locking piece 25L enters the lower locking recess 7b. Engage. However, the switching of the sliding piece 46 by the operation of the switching means is selectively performed when the needle bar 7L is located above the operating stroke SS.

Next, the operation of the driving force transmission device 11 configured as described above will be described.
As described above, when the operation protrusion 46a is switched to the driving force transmission position corresponding to the release pin 36 by the operation of the switching means, the release pin 36 is moved when the needle bar holder 17 is raised to the uppermost position of the operation stroke SS. Is pushed downward, and the locking levers 33L and 33R are rotated as described above to release the engagement between the locking hook portion 33b and the engaging recess 25a.

  Therefore, the pair of left and right swing levers 31L and 31R are simultaneously rotated clockwise in FIG. 5-1, by the spring force of the first compression coil springs 26L and 26R, and the first locking pieces 25L and 25R are The lock mechanism 27L in the non-engagement position is unlocked, and simultaneously engages with the lower locking recesses 7b of the corresponding needle bars 7L and 7R.

  Thus, when the main shaft 4 is rotated in a state where the first locking pieces 25L and 25R are respectively engaged with the corresponding lower locking recesses 7b, the needle bar crank 19 is rotated by the rotational driving force of the main shaft 4, A pair of left and right needle bars 7L, 7R are driven up and down synchronously over the operating stroke SS via the needle bar crank rod 18, the needle bar holder 17, and the first locking pieces 25L, 25R. Two-needle sewing is executed.

  That is, when the needle bar holder 17 is driven downward to the lowest position, as shown in FIG. 5A, the needle bars 7L and 7R are lowered to the lower limit position of the operation stroke SS, and the needle bar holder 17 is moved to the uppermost position. When driven up, as shown in FIG. 5B, the needle bars 7L and 7R rise to the upper limit position of the operating stroke SS.

  Here, even when the needle bars 7L and 7R are lowered to the lower limit position of the operation stroke SS, the upper ends of the needle bars 7L and 7R slightly protrude upward from the needle bar support frame 5. , 7R do not collide with the upper frame 5a of the needle bar support frame 5 respectively.

  Thus, in the driving state in which the pair of left and right needle bars 7L and 7R are driven to reciprocate up and down, the lower contact surface 12b of the operating levers 12L and 12R to which the first locking pieces 25L and 25R correspond is provided. Since the levers 12L and 12R are pushed rearward, the actuating levers 12L and 12R are rotated clockwise around the pivot pin 21 in FIGS. 5-1 and 5-2 so that the upper contact surface 12a becomes the upper locking recess 7a. The second locking pieces 41L and 41R do not engage with the upper locking recess 7a.

  Here, when the up / down driving of one of the needle bars 7L, 7R, for example, the left needle bar 7L, is interrupted, the sliding piece 46 is moved to the left swing lever 31L by operating the switching means. Switch to the corresponding left needle bar engagement release position. In this case, as described above, when the needle bar holder 17 is raised to the uppermost position by the rotation of the main shaft 4, the hook-shaped rear end of the swing lever 31L is pressed downward by the operating projection 46a, and the swing lever 31L is The first compression coil spring 26L is rotated counterclockwise against the spring force, the engagement with the lower locking recess 7b of the first locking piece 25L is released, and the locking mechanism 27L is moved to the non-engagement position. Locked.

  At this time, since the operating lever 12L is in a free state due to the first locking piece 25L retreating to the non-engaging position, the second locking piece 41L is engaged with the upper side of the needle bar 7L by the spring force of the compression coil spring 42L. Even when the needle bar holder 17 is lowered to the lowermost position as shown in FIG. 6A and the needle bar holder 17 is raised to the uppermost position as shown in FIG. The needle bar 7L is locked and held at an upper position of the operation stroke SS and is no longer driven up and down.

  By the way, when the main shaft 4 is rotationally driven at a high speed when operating the switching means to interrupt the vertical driving of either one of the two needle bars 7L and 7R that are driven up and down in synchronization. The protrusion timing when the second locking piece 41L engages with the upper locking recess 7a is delayed by the spring force of the compression coil spring 42L, and the upper locking recess 7a passes below the second locking piece 41L. In this case, since the needle bar 7L is not locked by any of the locking recesses 7a and 7b, the needle bar 7L comes off the needle bar support frame 5 and falls downward.

  However, even in such a case, as shown in FIG. 7, when the needle bar 7L is slightly lowered from the lower limit position of the operating stroke SS, the washer 22L fixed to the upper end of the needle bar 7L is Since the upper end of the upper frame 5a of the bar support frame 5 abuts on the upper side, the needle bar 7L does not fall down from the needle bar support frame 5. Therefore, it is possible to reliably prevent so-called needle bar slipping during sewing.

  Further, even when the needle bar can be prevented from coming off in this way, as shown in FIG. 7, the distance L between the upper and lower locking recesses 7a and 7b is larger than the operating stroke SS of the needle bar 7L. In a state where the washer 22L is locked by the needle bar support frame 5, the upper locking recess 7a of the needle bar 7L is larger than the first locking piece 25L at the upper limit position of the operating stroke SS. Since it is in the upper position, even when the needle bar holder 17 is driven up and down at a high speed over the operating stroke SS, the first locking piece 25L of the needle bar holder 17 is formed in the upper locking recess 7a. There is absolutely no engagement.

  Therefore, as in the conventional case, the first locking piece 25L is engaged with the upper locking recess 7a for some reason, and the lower end portion of the needle bar 7L repeatedly and strongly collides with the needle plate 10 of the bed portion 9. Such an accident can be reliably prevented, and the needle bar 7L and the needle plate 10 can be reliably prevented from being damaged.

  In addition, since the washers 22L and 22R are fixed to the upper ends of the needle bars 7L and 7R with screws 23L and 23R, respectively, the needle bars 7L and 22R are simply fixed to the needle bars 7L and 7R. 7R can be prevented from falling off.

  Further, the distance L between the upper and lower locking recesses 7a and 7b is set to be larger than the operation stroke SS of the needle bars 7L and 7R. That is, when the washers 22L and 22R are locked by the needle bar support frame 5, the upper locking recesses 7a of the needle bars 7L and 7R are from the first locking pieces 25L and 25R at the upper limit position of the operating stroke SS. Since the engagement between the first locking pieces 25L and 25R and the upper locking recess 7a can be reliably avoided during the vertical driving of the needle bar holding mechanism 13 by the driving force of the main shaft 4, Collision between the lower ends of the needle bars 7L and 7R and the needle plate 10 can be prevented, and the needle bars 7L and 7R and the needle plate 10 can be reliably prevented from being damaged.

  Next, a modified form of the embodiment will be described.

1] In order to prevent the needle bar 7L from coming off the needle bar support frame 5, the needle bar 7L is locked by various locking members provided on the sewing machine frame 2A in addition to the needle bar support frame 5. Also good. That is, as shown in FIGS. 8 and 9, the needle bar locking plate 50 formed in the machine frame 2 </ b> A on the rear side of the arm portion so as to be bent in a substantially horizontal L shape in a side view (this corresponds to a locking member). The vertical wall portion 50a is fixed.

  The horizontal wall portion 50b of the needle bar locking plate 50 extends horizontally toward the needle bars 7L and 7R, that is, in the front, at a height position just above the upper end of the upper frame 5a of the needle bar support frame 5. A pair of left and right cutouts 50c is formed in each part.

  The widths in the left-right direction of these notches 50c are slightly larger than the diameters of the needle bars 7L and 7R, and the needle bars 7L and 7R are supported on the inner side of the corresponding notches 50c so as to be vertically movable. Has been. Further, the washers 22L and 22R are fixed to the upper ends of the needle bars 7L and 7R with screws 23L and 23R, respectively, as in the above-described embodiment.

  Therefore, as in the above-described embodiment, even if either of the needle bars 7L and 7R is detached from the needle bar support frame 5 and falls downward during sewing, the needle bars 7L and 7R are operated. When the needle bars 7L and 7R are slightly lowered from the SS lower limit position, the washers 22L and 22R fixed to the upper ends of the needle bars 7L and 7R come into contact with the needle bar locking plate 50 from the upper side, so that the so-called needle bar removal during sewing is prevented. It can be surely prevented.

2] The engaged members provided on the needle bars 7L and 7R may be near the upper ends of the needle bars 7L and 7R. That is, as shown in FIG. 10, when the lengths of the upper portions of the needle bars 7L and 7R are somewhat longer and the needle bars 7L and 7R are slightly lowered from the lower limit position of the operating stroke SS, the needle bar support frame A ring member 51 (which corresponds to a locked member) that comes into contact with the upper frame 5a from above is welded to the needle bars 7L and 7R.

  Also in this case, the same operation and effect as in the above embodiment can be obtained by simply welding the ring member 51, which is a simple locked member, to the vicinity of the upper ends of the needle bars 7L and 7R.

3] The locked members provided on the needle bars 7L and 7R may be intermediate stages in the height direction of the needle bars 7L and 7R. That is, as shown in FIGS. 11 and 12, when the needle bars 7L and 7R are slightly lowered from the lower limit position of the operating stroke SS, the E-ring 52 contacts the lower frame 5b of the needle bar support frame 5 from above. (This corresponds to the locked member) is fitted into annular grooves 7e formed in the needle bars 7L and 7R, respectively. Also in this case, the same operation and effect as in the above embodiment can be obtained by simply mounting the E-ring 52, which is a simple locked member, on the middle stage of the needle bars 7L and 7R.

4] The locked members provided on the needle bars 7L and 7R are various protruding shapes such as pin members, thin plate-shaped or small block-shaped protruding members instead of the washers 22L and 22R, the ring member 51 and the E-ring 52. May be provided on the needle bars 7L and 7R.

5] A height position where an engagement recess is formed in an arbitrary part of the needle bars 7L and 7R which does not hinder the driving force transmission function, and the needle bars 7L and 7R fall off the needle bar support frame 5 downward. At this time, the needle pins 7L and 7R are supported so that the spring-engaged engagement pins provided in the needle bar support frame 5 engage with the engagement recesses of the needle bars 7L and 7R. It may be possible to prevent the frame 5 from falling off.

6) The present invention is not limited to the embodiments described above, and those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention. The present invention includes such modifications.

It is a principal part longitudinal front view of the arm part of the 2 needle | hook sewing machine which concerns on the Example of this invention. It is a left side view of the arm part of the two needle sewing machine concerning the example of the present invention. It is a front view of a needle bar. It is a disassembled perspective view of a needle bar holding. It is a principal part vertical side view at the time of needle bar lowering. It is a principal part vertical side view at the time of a needle bar raise. It is a principal part vertical side view at the time of needle bar holding down in a needle bar up-and-down movement stop state. It is a principal part vertical side view at the time of needle bar holding up in a needle bar up-and-down movement stop state. It is a principal part vertical side view at the time of needle bar holding up and down movement at the time of needle bar fall prevention. FIG. 3 is a diagram corresponding to FIG. 2 according to a first modification. It is a perspective view of a needle bar locking plate. FIG. 8 is a diagram corresponding to FIG. 7 according to a second modification. FIG. 10 is a view corresponding to FIG. 5A according to a third modified embodiment. It is a needle bar crossing top view of FIG.

Explanation of symbols

1 Two-needle sewing machine 4 Main shaft 5 Needle bar support frame 5a Upper frame 5b Lower frame 7L Needle bar 7R Needle bar 7a Upper locking recess 7b Lower locking recess 7d Vertical groove 11 Driving force transmission device 12L Actuating lever 12a Upper contact Surface 12b Lower abutting surface 13L Needle bar holding mechanism 13R Needle bar holding mechanism 14L Needle bar locking mechanism 14R Needle bar locking mechanism 15 Operation mechanism 17 Needle bar holding 19 Needle bar crank 21 Pivoting pin 22L Washer 22R Washer 25L First 1 locking piece 25R 1st locking piece 26L 1st compression coil spring 26R 1st compression coil spring 27L lock mechanism 27R lock mechanism 31L swing lever 31R swing lever 33L lock lever 33R lock lever 36 release pin 41L second lock Piece 41R second locking piece 42L compression coil spring 42R compression coil spring 46 sliding piece 50 needle bar locking plate 51 ring member 52 E ring

Claims (5)

In a driving force transmission device for a two-needle sewing machine that individually transmits a driving force of a main shaft to two parallel needle bars supported by a needle bar support frame so as to be movable up and down,
Upper and lower locking recesses formed on each needle bar at a predetermined interval in the vertical direction;
An operating lever that is movably mounted in a longitudinal groove formed in each needle bar over the upper and lower locking recesses and whose middle portion in the length direction is pivotally supported by a pivot pin. An actuating lever having a contact surface that can protrude so as to selectively close the upper and lower locking recesses;
A needle bar holding mechanism connected to a needle bar crank connected to the main shaft, a movable first locking piece engageable with a lower locking recess of each needle bar, and the first locking piece A needle bar holding mechanism comprising: a first biasing member that biases the first engagement piece to the engagement side; and a lock mechanism that locks the first locking piece in a non-engagement position;
The needle bar support frame includes a second locking piece that can be engaged with the upper locking recess of each needle bar and a second biasing member that biases the second locking piece toward the engagement side. A needle bar locking mechanism;
When one of the needle bars is at an upper position of the operation stroke, the first locking piece is disengaged from the lower locking recess of the needle bar and the lock mechanism is unlocked selectively. Operating mechanism for
In order to prevent the needle bar from falling off from the needle bar support frame, a lock provided on the sewing machine frame side when each needle bar slightly falls below the lower limit position of the operation stroke with respect to the needle bar support frame. A locked member that is locked by a member and provided on each needle bar;
A drive force transmission device for a two-needle sewing machine comprising:   The driving force transmission device for a two-needle sewing machine according to claim 1, wherein the locked member is a protruding member that protrudes horizontally from the outer periphery of the needle bar.   The driving force transmission device for a two-needle sewing machine according to claim 2, wherein the protruding member is fixed to an upper end portion of the needle bar or its vicinity, and the locking member is the needle bar support frame.   The driving force transmission device for a two-needle sewing machine according to any one of claims 1 to 3, wherein a distance between the upper and lower locking recesses is set larger than an operation stroke of the needle bar.   In a state where the locked member is locked by the locking member, the upper locking recess of each needle bar is located above the first locking piece at the upper limit position of the operation stroke. The driving force transmission device for a two-needle sewing machine according to any one of claims 1 to 4.

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