JP4722440B2 - Needle bar mechanism of two-needle sewing machine - Google Patents

Description

  The present invention relates to a needle bar mechanism of a sewing machine that performs sewing using two needle bars simultaneously or selectively.

  In a needle bar mechanism of a two-needle sewing machine having a one-needle stop function capable of selectively stopping the vertical movement of a pair of needle bars, a pair of needle bars having first and second engagement holes A needle bar support that individually supports a pair of needle bars so as to be movable up and down, and a needle bar vertical movement mechanism that moves each needle bar up and down using a needle bar holder that individually holds the pair of needle bars; A clutch mechanism that includes a clutch member that inserts and removes the tip from the first engagement hole and that can selectively switch the holding of each needle bar by the needle bar holding between a holding state and a released state; A stopper member that is inserted into and removed from the second engagement hole, and a stopper mechanism that holds the needle bar that has been released from the holding state with respect to the needle bar by the clutch mechanism on the needle bar support. (For example, refer to Patent Document 1).

  The two needle bars move up and down together with the needle bar holding the clutch member of the clutch mechanism in the first engagement hole. Further, in order to stop the vertical movement of one needle bar, the clutch member of the needle bar is retracted to be released, and a stopper member is inserted into the second engagement hole. As a result, one of the needle bars is released from the needle bar holder and is held with respect to the needle bar support.

A two-needle sewing machine equipped with such a needle bar mechanism has two lines in a straight section when a double parallel seam is formed along the edge of the cloth to be sewn, such as a pocket of a trouser. Sewing is performed by moving the needles up and down at the same time, and the number of stitches on the inner side is reduced at the corners, so that the vertical movement of the inner sewing needle is temporarily stopped.
JP-A-1-300990

However, in the conventional needle bar mechanism of the two-needle sewing machine, when the vertical movement of any needle bar is stopped or when the vertical movement is resumed from the stopped state, the needle bar mechanism is not held by the stopper mechanism or the clutch mechanism. In some cases, the needle bar may come off and fall. And, if the sewing operation is continued in a state where the needle bar is dropped or is dropped and pierced deeply into the sewing product, there is a risk of damage to the sewing machine or the sewing machine components such as the sewing needle. There was a problem.
Furthermore, if the needle bar falls, the clutch member may be inserted into the second engagement hole of the needle bar. In this case, the needle bar moves up and down at a position lower than normal. Thus, there is a problem that a sewing product or a sewing machine component located below the sewing needle is struck by the sewing needle or the needle bar and is damaged.

  An object of the present invention is to suppress the problem of needle bar dropping.

The invention according to claim 1 is a needle bar mechanism of a two-needle sewing machine having a one-needle stop function capable of selectively stopping the vertical movement of a pair of needle bars, and a pair of needle bars for holding a sewing needle; A needle bar support that individually supports a pair of needle bars so as to be movable up and down, a needle bar vertical movement mechanism that moves each needle bar up and down using a needle bar holder that individually holds the pair of needle bars, and a needle bar A clutch mechanism capable of selectively switching the holding of each needle bar by holding between a holding state and a releasing state; a stopper mechanism for holding the needle bar released from the holding state by the clutch mechanism on the needle bar support; Each needle bar has a locking mechanism for preventing the fall of the needle bar that is locked to the needle bar holder and is not held by either the clutch mechanism or the stopper mechanism. The structure of providing a part is adopted.

In the above configuration, when the two needle bars are held in the clutch mechanism, they move up and down together with the needle bar holding.
In order to move only one needle bar up and down, the other needle bar is held on the needle bar support by the stopper mechanism while being released from the clutch mechanism. Thus, the other needle bar is restricted from moving up and down, and only one needle bar moves up and down.
In the configuration described above, even when the needle bar is missed by the stopper mechanism or the clutch mechanism, the needle bar is locked to the needle bar holder by the locking portion, and the fall is prevented. Further, since the needle bar is locked on the needle bar holding by the locking part, the needle bar moves up and down together with the needle bar holding. However, since the needle bar hug does not hold the needle bar, the upward movement of the needle bar relative to the needle bar hug is not restricted, and the needle bar is lowered as the needle bar hug is lowered. However, the sewing needle does not strike the construction of the sewing object or sewing machine located below the sewing needle.

  The invention according to claim 2 has the same configuration as that of the invention according to claim 1, and a second engagement in which each needle bar is engaged with a first engagement hole with which a clutch mechanism is engaged and a stopper mechanism is engaged. The engaging portion is provided, and the engaging portion is arranged so that the stopper mechanism can be engaged with the second engaging hole by moving the needle bar holding to the top dead center, or the first engaging hole is clutched. The arrangement is such that each needle bar is provided in an arrangement capable of engaging the mechanism.

In the above configuration, as described above, when the locking portion is engaged with the needle bar holder so that the needle bar does not fall from the needle bar holder, the upward movement of the needle bar is not restricted. When it rises to the dead point, only the needle bar jumps upward due to inertial force. Therefore, by providing a locking portion on the needle bar within the range where the second engagement hole reaches the stopper mechanism or the first engagement hole reaches the clutch mechanism due to the needle bar jumping up, Even in the case of dropping, when the needle bar hug moves to the top dead center, the needle bar is bounced upward to restore the holding state by the stopper mechanism or the clutch mechanism.
The “arrangement in which the stopper mechanism can be engaged with the second engagement hole or the arrangement in which the clutch mechanism can be engaged with the first engagement hole” means the needle as described above. This includes both arrangements that allow for and without consideration of rod bounce.
In other words, when the bounce is taken into consideration, the position where the locking portion locks the needle bar with respect to the needle bar hug is lower than the first bounce distance of the needle bar than the clutch mechanism. Or when the needle bar hug is located at the top dead center, the second engagement hole is positioned below the stopper mechanism within the range of the needle bar jumping distance.
In addition, when jumping is not taken into consideration, the position where the locking portion locks the needle bar with respect to the needle bar hug is the position where the clutch mechanism and the first engagement hole coincide with each other, or the needle bar hug is the upper position. When located at the dead point, the stopper mechanism and the second engagement hole coincide with each other.

  The invention according to claim 3 has the same configuration as that of the invention according to claim 2, is arranged above the needle bar holder when the stopper mechanism is located at the top dead center, and the locking portion is the first. It is provided at a position between the engagement hole and the second engagement hole.

In the above configuration, the fact that the stopper mechanism is positioned above the needle bar holder at the top dead center position means that the stopper mechanism is positioned above the clutch mechanism. Therefore, the second engagement hole of the needle bar is disposed above the first engagement hole.
In such a case, when the needle bar is removed from the clutch mechanism and the stopper mechanism and falls, the second engagement hole positioned above the first engagement hole is engaged with the clutch mechanism, The needle bar may be held by the needle bar holder at a lower position than usual.
However, since the locking part is provided between the first engagement hole and the second engagement hole, even if the needle bar falls, it is restrained at the position of the locking part with respect to the needle bar hug, The second engagement hole of the needle bar cannot reach the needle bar holder. Therefore, the clutch mechanism does not engage with the second engagement hole.

The invention described in claim 4 has the same configuration as that of the invention described in claim 1, 2, or 3, and adopts a configuration in which the locking portion is an E-ring mounted on the needle bar.
In the above configuration, even when the needle bar is disengaged from the clutch mechanism or the stopper mechanism, the E-ring provided on the needle bar is locked to the needle bar holder, thereby preventing the needle bar from falling.

According to the first aspect of the present invention, since each needle bar has a locking portion, it is possible to prevent the needle bar from dropping even if the needle bar is removed from the stopper mechanism or the clutch mechanism.
Further, since the locking portion prevents the needle bar from descending with respect to the needle bar holder and the upward movement of the needle bar is not restricted, the needle bar can be sent out further upward when the needle bar holder is raised, The possibility of re-holding by the clutch mechanism or the stopper mechanism can be obtained.

The invention according to claim 2 is an arrangement in which the locking portion can be engaged with the stopper mechanism to the second engagement hole by moving the needle bar to the top dead center or the first engagement hole. Since each needle bar is provided in such an arrangement that the clutch mechanism can be engaged with the needle mechanism, even if the needle bar is removed from the clutch mechanism or the stopper mechanism, the needle bar hug subsequently raised to the top dead center. Sometimes, the needle bar is moved to a position where it can be held by the clutch mechanism or the stopper mechanism, and can be held again by the clutch mechanism or the stopper mechanism.
Therefore, even when the needle bar is no longer held, there is no need to interrupt the sewing operation, and the work efficiency can be improved. Further, since the return work is not required, it is possible to further improve the work efficiency.

  In the invention according to claim 3, since the locking portion is provided between the first engagement hole and the second engagement hole of the needle bar, even if the needle bar falls, the locking portion Thus, the needle bar is prevented from dropping before the second engagement hole reaches the needle bar hug. For this reason, it is possible to avoid the vertical movement of the needle bar at a position lower than usual due to the clutch mechanism engaging with the second engagement hole, and the sewing needle, the needle bar or the lower side thereof can be avoided. It is possible to more effectively prevent damage to the sewn product and the sewing machine component.

  Since the invention according to claim 4 uses an E-ring having high versatility and high flowability as the engaging portion, it is possible to improve the productivity of the apparatus. In addition, the E-ring can improve productivity because it is easy to mount, and can be easily installed on an existing needle bar mechanism, thus saving and regenerating existing resources. It becomes possible.

(Overall configuration of the embodiment of the invention)
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
1 is a front view of a needle bar mechanism 10 of a two-needle sewing machine according to an embodiment of the present invention, FIG. 2 (A) is a side view with a part of the needle bar 20 omitted, FIG. 2 (B) is a front view, and FIG. These show the front view of the needle bar mechanism 10 when the needle bar is lowered. This needle bar mechanism 10 is provided inside the tip of an arm portion (not shown) of the two-needle sewing machine, and simultaneously or selectively moves a pair of needle bars 20 that individually hold two sewing needles (not shown). It is something to move. In the following description, the vertical vertical direction is the Z-axis direction, the longitudinal direction of the arm part of the two-needle sewing machine in the state where it is installed on the horizontal plane is the Y-axis direction, parallel to the plate surface of the needle plate (not shown) and orthogonal to the Y-axis direction. The direction to perform is the X-axis direction. Note that the X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other.

  A needle bar mechanism 10 of a two-needle sewing machine individually supports a pair of needle bars 20 each having a first engagement hole 21 and a second engagement hole 22 and each needle bar 20 is movable up and down. A needle bar up-and-down moving mechanism 50 for moving each needle bar 20 up and down using a needle bar support frame 40 as a needle bar support to be used, and a needle bar holder 51 for holding a pair of needle bars 20 individually, and each needle bar The holding of each needle bar 20 by the needle bar holder 51 can be selectively switched between the holding state and the released state by using a pair of clutch members 61 for inserting and removing the tip from the first engagement hole 21 of the 20. The needle bar support frame 40 is held by using a clutch mechanism 60 and a stopper member 71 for inserting and removing the tip of the needle bar 20 from the second engagement hole 22 released from being held by the clutch mechanism 60. Stopper mechanism 70 and either needle bar 2 by an artificial input operation And a switching mechanism 80 for switching the released state and the holding state of the clutch mechanism 60 to select.

(Needle bar)
Each needle bar 20 is normally supported by the needle bar support frame 40 in a state along the Z-axis direction. When performing needle swinging, the needle bar 20 is interposed at the intermediate position in the longitudinal direction of each needle bar 20 via the needle bar support frame 40. A rotational swing motion is applied about an axis along the Y-axis direction. When such swinging is performed, the upper and lower ends of each needle bar 20 swing along the X-axis direction.

Each needle bar 20 is a rod-like body having a flat surface 23 formed on a part of the circumferential surface of a round bar having a circular cross section, as shown in the figure, and holds a sewing needle (not shown) at its lower end.
In a state where the needle bar 20 is supported along the Z-axis direction, the flat surface 23 is supported by the needle bar support frame 40 so as to be in a state along the YZ plane. A groove portion 24 is formed along the longitudinal direction at the intermediate position in the Z-axis direction on the flat surface 23.

Further, a first engagement hole 21 and a second engagement hole 22 are formed on the flat surface 23 in the vicinity of the lower end and the upper end of the groove 24 so as to overlap the groove 24. Has been.
The first engagement hole 21 is formed in a rectangular shape corresponding to the tip shape so that the tip portion of the clutch member 61 can be inserted. Such a rectangular shape corresponds to the front end portion of the clutch member 61 protruding in a substantially rectangular shape, and the length of the long side and the short side of the rectangle are the width of the front end portion of the substantially rectangular shape of the clutch member 61, respectively. It is set slightly larger than the vertical width.
The second engagement hole 22 is located above the first engagement hole 21 and has a rectangular shape in front view and half in side view corresponding to the shape of the tip of a stopper member 71 described later. It is formed in a circular shape.

An oscillating plate 25 is swingably attached to the inside of the groove portion 24 along the longitudinal direction of the groove portion 24. The swing plate 25 is supported by a support shaft along the Y-axis direction at an intermediate position between the first engagement hole 21 and the second engagement hole 22, and both ends of the swing plate 25 are X-axis by swinging. Move along the direction. That is, one end and the other end of the swing plate 25 move in the first engagement hole 21 and the second engagement hole 22 along the depth direction of the engagement holes 21 and 22, respectively. .
Further, when one end of the swing plate 25 is pushed into the vicinity of the deep portion of the first engagement hole 21, the other end is pushed out to the flat surface 23 in the second engagement hole 22, and the other end is pushed. When pushed into the vicinity of the deep portion of the second engagement hole 22, one end portion is formed into a shape that is pushed out to the flat surface 23 in the first engagement hole 21.
That is, for the same needle bar 20, when the clutch member 61 is inserted into the first engagement hole 21, the stopper member 71 that has already been inserted into the second engagement hole 22 is pushed out by the swing plate 25. When the clutch member 71 is inserted into the second engagement hole 22, the clutch member 61 that has already been inserted into the first engagement hole 21 is pushed out by the swing plate 25.

Further, when the needle bar 20 moves up and down, the needle bar 20 is engaged with the clutch mechanism 60 through the first engagement hole 21 and held by the needle bar holder 51. On the other hand, when the vertical movement is stopped for sewing with one needle, the clutch mechanism 60 is released and the second engagement hole 22 engages with the stopper mechanism 70 to hold the needle bar support frame 40.
As described above, each needle bar 20 is normally held by either the clutch mechanism 60 or the stopper mechanism 70, but the engagement to each engagement hole is not successful, and the clutch mechanism 60 or the stopper The mechanism 70 may fall off.
For this reason, in order to prevent such drop-off, each needle bar 20 has an E-ring 26 as a first locking hole 21 as a locking part for preventing the locking to be stopped by being locked by the needle bar holder 51. And the second engagement hole 22. In other words, the E-ring 26 is used whose outer diameter is larger than the outer diameter of the entire needle bar 20, so that it cannot pass through the insertion hole of the needle bar holder 51, and the upper end portion of the needle bar holder 51 This prevents the needle bar 20 from falling.

The E-ring 26 is arranged in the longitudinal direction of the needle bar 20 so that a slight gap is provided upward from the upper end of the needle bar holder 51 when the clutch mechanism 60 is engaged with the first engagement hole 21. Is set to the correct position. The E-ring 26 is disposed when the stopper mechanism 70 is engaged with the second engagement hole 22 and a slight gap is provided above the upper end of the needle bar holder 51 at the top dead center position. (See FIG. 4).
When the E-ring 26 is arranged as described above, the needle bar 20 that has dropped off moves downward by the amount of the gap, and with the needle bar holder 51 in a state where the E-ring 26 is in contact with the upper end of the needle bar holder 51. It will move up and down. Then, when the needle bar holder 51 moves to the top dead center, the needle bar 20 is raised by the inertial force, and the first engagement hole 21 is engaged with the clutch mechanism 60, or the second engagement hole is a stopper. Engage with mechanism 70. Therefore, the needle bar can be returned from the dropped state.
The clearance between the E-ring 26 and the upper end of the needle bar holder 51 is a distance by which the needle bar holder 20 in a free state is flipped up at the top dead center position with respect to the needle bar holder 51 at a general sewing speed. If it is in the range, it may be set larger.
Further, the E-ring 26 is disposed at a position where it is just in contact with the upper end portion of the needle bar holder 51 when the clutch mechanism 60 is engaged with the first engagement hole 21 or at the second engagement hole 22 with a stopper mechanism. It is good also as a position which is the case where 70 is engaged and just touches the upper end part of needle bar holding 51 in a top dead center position. In this case, the holding state can be restored without waiting for the needle bar 20 to jump at the top dead center position.

(Needle bar support frame)
FIG. 4 is a cross-sectional view of the needle bar mechanism 10 passing through the center line of one needle bar 20 and along the XZ plane. As shown in FIGS. 1 and 4, the needle bar support frame 40 is formed with insertion holes through which upper and lower needle bars 20 are inserted so that two needle bars 20 are arranged in the Y-axis direction. The rod 20 is supported so as to be movable up and down.
In the vicinity of the support portion of the needle bar 20 at the lower portion of the needle bar support frame 40, a supply member 41 such as a nonwoven fabric or urethane to which lubricating oil or grease is supplied is provided, and slides on the supply member 41. Each needle bar 20 is arranged as described above. Thereby, lubricating oil or grease is supplied to the sliding part of each needle bar 20 and the needle bar support frame 40, and the vertical movement is performed smoothly.

A stopper mechanism 70 is provided in the vicinity of the support portion of the needle bar 20 above the needle bar support frame 40, and a switching mechanism 80 is provided immediately below the stopper mechanism 70 of the needle bar support frame 40. Yes. The stopper mechanism 70 and the switching mechanism 80 will be described in detail later.
Further, in the vicinity of the needle bar 20 supported by the needle bar support frame 40, vertical movement of a square piece 55 provided at one end of a link body 54 that applies a driving force for vertical movement to each needle bar 20. A guide groove 42 for guiding the above is formed.

  In addition, one end of a swing shaft 43 that applies a swing driving force for swinging the needle is connected to an intermediate position in the vertical direction at one end of the needle bar support frame 40 in the Y-axis direction. The swing shaft 43 is supported by the sewing machine frame so as to be rotatable along the Y-axis direction, and is connected to a swing mechanism that swings in synchronization with the vertical movement of the needle bar 20. Further, the swing mechanism can adjust the swing angle range from 0 to a predetermined angle range by a well-known configuration, and if necessary, the sewing needles held by the needle bars 20 can be moved along the X-axis direction. It is possible to swing the needle with an arbitrary swing width. Further, as described above, the swing mechanism of the needle swing is adjusted so that each needle bar 20 is in a state along the Z-axis direction when the needle swing is not performed.

(Needle bar vertical movement mechanism)
As shown in FIG. 1, the needle bar vertical movement mechanism 50 includes a needle bar holder 51 that supports each needle bar 20 via a clutch mechanism 60, and a sewing machine motor (not shown) that is a vertical movement drive source for each needle bar 20. ) Of the sewing machine main shaft 52, the rotary weight 53 fixedly installed at one end of the sewing machine main shaft 52, the link body 54 connecting the rotary weight 53 and the needle bar holder 51, And a square piece 55 for moving the end on the side of the needle bar along the Z-axis direction.

The needle bar holder 51 is formed with insertion holes through which the two needle bars 20 are inserted in parallel, and the needle bar 20 inserted into each insertion hole is held by the clutch mechanism 60.
The sewing machine main shaft 52 is rotatably supported by the sewing machine frame in a state along the Y-axis direction. One end of the sewing machine main shaft 52 is connected to the sewing machine motor, and the other end is connected to the rotation center position of the disk-shaped rotating weight 53.
The link body 54 is connected so that one end of the link body 54 is eccentric from the center of the rotary weight 53 so as to be rotatable about the Y-axis direction, and the other end is rotatable about the Y-axis direction with respect to the needle bar holder 51. It is connected to.
The square piece 55 provided at the other end of the link body 54 is restricted by the guide groove 42 of the needle bar support frame 40 so as to be movable only along the Z-axis direction (longitudinal direction of the supported needle bar 20). ing. For this reason, one end portion of the link body 54 makes a circular motion together with the rotary weight 53, but the other end portion of the link body 54 only moves up and down, and as a result, moves up and down each needle bar 20 via the needle bar holder 51. A driving force is applied.

(Clutch mechanism)
As shown in FIGS. 1 and 4, the clutch mechanism 60 includes two clutch members 61 inserted into circular support holes 57 penetrating from the front of the needle bar holder 51 to the respective insertion holes, and each clutch member 61. The two driven links 62 that are moved forward and backward individually, the two pressing springs 63 that individually apply the moving force in the forward direction to the clutch members 61 via the driven links 62, and the clutch members 61 are moved backward. Two locking claws 64 that are respectively locked in the state (retracted position), two pressing springs 65 that are respectively pressed in the direction in which each locking claw 64 is locked, and the locking by each locking claw 64 is released And a release pin 66 capable of inputting an operation to be performed from the outside.

The two support holes 57 of the needle bar holder 51 are formed along the X-axis direction, and support the substantially cylindrical clutch member 61 slidably along the X-axis direction.
FIG. 5 is a perspective view of the clutch member 61. Each clutch member 61 has a protrusion 61a having a substantially rectangular front end surface at the front end (end on the needle bar 20 side). The tip shape and the size of the protrusion 61a are substantially the same as the shape of the first engagement hole 21 of the needle bar 20, and the first movement of the clutch member 61 (movement toward the needle bar 20 side) causes the first protrusion hole 61a. Can be inserted into the engagement hole 21. Further, the front end surface 61b of the protrusion of each clutch member 61 is formed in a somewhat inclined state, and can be easily inserted into the first engagement hole 21.
When the protrusion 61 a of the clutch member 61 is inserted into the first engagement hole 21, the needle bar 20 is held with respect to the needle bar holder 51, and the needle bar 20 can be moved up and down together with the needle bar holder 51. It becomes possible. When the protrusion 61a of the clutch member 61 is inserted into the first engagement hole 21, the lower end of the swing plate 25 provided in the groove 24 of the needle bar 20 is pressed, and the lower end moves backward. In addition, the upper end moves forward.
Furthermore, a notch 61c is formed at the lower part of the protrusion 61a of each clutch member 61, and the tip of the locking claw 64 is locked. The notch 61c is engaged with the locking claw 64 only when the clutch member 61 is retracted to a predetermined retracted position (a position where the protrusion 61a at the tip thereof does not reach the first engagement hole 21 of the needle bar 20). It is provided at a position where it can be stopped.

Each driven link 62 is formed in a bent shape in the middle thereof, and is supported by the needle bar holder 51 so as to be swingable at the bent intermediate portion. One end of the driven link 62 is connected to the rear end of the clutch member 61, and the other end is always pressed by the pressing spring 63. The pressing spring 63 presses the driven link 62 so as to swing in the direction in which the clutch member 61 moves forward.
Further, each driven link 62 is pressed from below by the pressing spring 63 against the other end portion. When the clutch member 61 is moved backward, the other end of the driven link 62 is moved by the upward movement of the needle bar holder 51. The contact protrusion 81a of the switching member 81 of the switching mechanism 80, which will be described later, is brought into contact with the portion from above, and the clutch member 61 can be moved backward by being pushed down and rocked against the pressing spring 63. ing.

  Each locking claw 64 is supported by a needle bar holder 51 so as to be swingable below the clutch member 61. Each of the locking claws 64 can swing up and down at its swing end, and swings upward to enter the notch 61c of the clutch member 61 whose tip end is in the retracted position. It is possible to hold so as not to. Each pressing spring 65 always presses each locking claw 64 upward from below. Therefore, the claw tip of the locking claw 64 is urged toward the clutch member 61, and the claw tip is quickly inserted when the clutch member 61 moves backward and the notch 61c reaches the claw position. The

The release pin 66 is provided through the needle bar holder 51 up and down from the upper end portion of the needle bar holder 51 to reach each locking claw 64 through the respective clutch members 61 and is movable up and down. It is supported. The lower end portion of the release pin 66 is disposed so as to be simultaneously contactable with a contact portion (not shown) provided on each locking claw 64. In other words, the half region of the lower end surface of the release pin 66 is in contact with the contact portion of one locking claw 64, and the remaining half region is in contact with the contact portion of the other locking claw 64. Yes.
The release pin 66 is always pressed upward by a spring (not shown), and the upper end of the release pin 66 protrudes above the needle bar holder 51. The upper end portion of the release pin 66 is pressed downward by the contact protrusion 81a of the switching member 81 of the switching mechanism 80, which will be described later, by the upward movement of the needle bar holder 51, and is in the locked state. The tip of the locking claw 64 is pushed downward to release the locking.

(Switching mechanism)
The switching mechanism 80 includes a guide groove portion 82 formed in the needle bar support frame 40 at a position slightly above the top dead center of the needle bar holder 51, and a switching member 81 slidably supported along the guide groove portion 82. And a pressing cover 83 that prevents the switching member 81 from falling off the guide groove portion 82.
The guide groove portion 82 is formed along the Y-axis direction in the upper portion of the needle bar support frame 40, and supports the switching member 81 so as to be slidable along the same direction.

The switching member 81 has a substantially prismatic shape as a whole, an abutting projection 81a projecting in a direction perpendicular to the longitudinal direction is formed at one end, and the other end is provided outside the sewing machine frame. Not connected to operation input means.
The switching member 81 is supported by the guide groove portion 82 in a state where the contact protrusion 81a is directed downward. Then, the movement of the switching member 81 along the Y-axis direction pushes one of the driven links 62, the other driven link 62, or the release pin 66 of the clutch mechanism 60 when the needle bar holder 51 reaches the top dead center. The contact protrusion 81a can be switched to a possible position. The contact protrusion 81a is switched by an artificial operation on the operation input means described above from outside the sewing machine frame. The contact protrusion 81a can be pushed downward by the stroke required for each release operation with respect to each of the driven links 62 and 62 and the release pin 66 of the needle bar holder 51 raised to the top dead center position. The protruding length is set.

(Stopper mechanism)
The stopper mechanism 70 includes a support portion 72 having two circular through holes penetrating from the front surface of the needle bar support frame 40 to the insertion hole of the needle bar 20 at the upper end portion of the needle bar support frame 40, and each of the support portions 72. Two stopper members 71 inserted into the through holes, two pressing springs 73 that individually apply a moving force in the forward direction (needle bar 20 side) to each stopper member 71, and each pressing spring 73 are supported in the rear. And a cover body 74 that covers and closes the through hole of the support portion 72.

Each through hole of the support portion 72 is formed along the X-axis direction, and supports the substantially cylindrical stopper member 71 so as to be slidable along the X-axis direction.
FIG. 6 is a perspective view of the stopper member 71. Each stopper member 71 has a tip 71a (end on the needle bar 20 side) having a rectangular shape when viewed from the front in the X-axis direction, and a tip having a semicircular shape when viewed from the side in the Y-axis direction. Yes. The shape of the tip 71a corresponds to the shape of the second engagement hole 22 described above.
As described above, the stopper member 71 is pressed forward from the rear by the pressing spring 73. When the leading end 72 a of the stopper member 72 is inserted into the second engagement hole 22 by such pressing, the needle bar 20 is prevented from moving up and down with respect to the needle bar support frame 40.

However, the force for swinging the swinging plate 25 by the pressing force of the pressing spring 73 against each stopper mechanism 71 swings the swinging plate 25 by the pressing force that the pressing spring 65 applies to the clutch member 61 via the driven link 62. It is set smaller than the force to move. Therefore, when the projection 61a of the clutch member 61 and the tip 71a of the stopper member 71 are to be inserted into the first engagement hole 21 and the second engagement hole 22, respectively, the projection 61a of the clutch member 61 is The tip 71a of the stopper member 71 is pushed and lost so that it cannot enter the second engagement hole 22.
Further, when the distal end portion 71a of the stopper member 71 is inserted into the second engagement hole 22, the upper end portion of the swinging plate 25 provided in the groove portion 24 of the needle bar 20 is pressed, and the upper end portion is advanced. The lower end can be moved backward while being moved.

  Note that the distance in the Z-axis direction from the clutch member 61 of the clutch mechanism 60 to the stopper member 71 of the stopper mechanism 70 when the needle bar holder 51 is at the top dead center is from the first engagement hole 21 of the needle bar 20. The distance is set so as to coincide with the distance to the second engagement hole 22. Thereby, when the needle bar holder 51 is at the top dead center position, the needle movement 20 can be switched to the holding state by the stopper mechanism 70, or the needle bar 20 in the holding state can be engaged with the clutch mechanism 60. Yes.

(Description of the operation of the needle bar mechanism of the two-needle sewing machine)
The operation of the needle bar mechanism 10 of the two-needle sewing machine will be described with reference to FIGS. FIGS. 7 and 9 are diagrams for explaining the operation of the needle bar mechanism 10, and FIG. 8 is a cross-sectional view of the needle bar mechanism 10 with a cross section passing through the center line of one needle bar 20 in the operation state of FIG.
FIG. 1 shows a state in which each needle bar 20 is held by a needle bar holder 51 at the top dead center position, and the description of the operation starts here.

By driving the sewing machine motor, a downward moving force is applied to the needle bar holder 51 via the sewing machine main shaft 52, the rotary weight 53 and the link body 54 of the needle bar vertical movement mechanism 50. As a result, the needle bar holder 51 moves to the bottom dead center together with the two needle bars 20 (state shown in FIG. 3).
When one needle bar 20 (here, the left needle bar 20 will be described as an example) is stopped vertically, the needle bar holder 51 is returned to the top dead center again through the lowering. Further, an operation input means (not shown) provided outside the sewing machine frame is operated to align the contact protrusion 81a of the switching member 81 with the upper position of the left driven link 62.

When the needle bar holder 51 is moved to the top dead center again by driving the sewing machine motor, the contact protrusion 81a of the switching member 81 presses the left driven link 62 downward (states of FIGS. 7 and 8).
As a result, the left driven link 62 moves the clutch member 61 in the backward direction against the pressing spring 63, and the distal end portion of the locking claw 64 below the clutch member 61 is pressed by the pressing spring 65. The clutch member 61 is locked so as not to advance by entering the notch.
Further, when the clutch member 61 moves backward, the clutch member 61 comes out of the first engagement hole 21, and the lower end portion of the swing plate 25 in the groove portion 24 of the left needle bar 20 is released from the pressed state. The distal end portion of the stopper member 71 that has been in pressure contact enters the second engagement hole. As a result, the left needle bar 20 is held by the needle bar support frame 40 at the top dead center position.
Therefore, as shown in FIG. 9, when the needle bar holder 51 moves down again, only the right needle bar 20 moves down together with the needle bar holder 51, and the left needle bar 20 remains at the top dead center position.

  In order to move the needle bar 20 up and down again from this state, an operation input means (not shown) provided outside the sewing machine frame is operated between the start of the lowering of the needle bar holder 51 and the return to the top dead center. Then, the contact protrusion 81 a of the switching member 81 is aligned with the upper position of the release pin 66.

When the needle bar holder 51 is moved again to the top dead center by driving the sewing machine motor, the contact protrusion 81a of the switching member 81 presses the release pin 66 downward (state shown in FIGS. 1 and 4).
Thereby, the lower end portion of the release pin 66 presses the contact portion of the left locking claw 64, and moves the distal end portion of the locking claw 64 downward against the pressing spring 65. As a result, the latching claw 64 is released from the latched state of the clutch member 61 with the notch 61c, and the clutch member 61 is moved forward by being pressed by the pressing spring 63. Then, the clutch member 61 enters the first engagement hole 21 of the needle bar 20 held by the needle bar support frame 40, presses the lower end portion of the swing plate 25, and presses the upper end portion. 71 is pushed back and sent out of the second engagement hole 22.
As a result, the state where the needle bar 20 is held by the stopper member 71 is released, the needle bar 20 is held by the needle bar holder 51, and starts to move up and down again.

  Moreover, in the process of the said operation | movement, the place which should hold | maintain the needle bar 20 with the clutch mechanism 60 or the stopper mechanism 70 is not hold | maintained for a certain factor, and the needle bar 20 may fall. At this time, the E-ring 26 comes into contact with the upper end of the needle bar holder 51 due to the drop of the needle bar 20. In other words, the needle bar 20 drops by the gap distance between the preset E ring 26 and the upper end of the needle bar holder 51. When the needle bar holder 51 moves upward to the upper end in such a state, the needle bar 20 jumps upward with respect to the needle bar holder 51 due to the inertial force, and the clutch member 61 moves relative to the first engagement hole 21. The arrangement is such that the stopper member 71 can be inserted into the second engagement hole 22. Therefore, the needle bar 20 returns to the holding state by the clutch mechanism 60 or the stopper mechanism 70 from the dropped state.

(Effect of embodiment)
In the needle bar mechanism 10 described above, each needle bar 20 is provided with an E-ring 26 as a locking portion. Therefore, even if the needle bar 20 is removed from the stopper mechanism 70 or the clutch mechanism 60, it can be prevented from falling. Become.
Further, the E-ring 26 is disposed slightly above the upper end of the needle bar holder 51 when the clutch mechanism 60 is engaged with the first engagement hole 21, or a stopper mechanism When 70 engages with the second engagement hole 22, it is disposed slightly above the upper end of the needle bar holder 51 at the top dead center position. Therefore, the needle bar 20 after dropping moves up and down together with the needle bar holder 51, and the needle bar 20 jumps due to inertial force at the top dead center position. The joint hole 22 can be moved to the holding position of the clutch mechanism 60 or the stopper mechanism 70, and the holding state of the needle bar 20 can be restored by being held by these holes.
Accordingly, even when the needle bar 20 is no longer held, it is not necessary to interrupt the sewing work, and the work efficiency can be improved. Further, since the return work is not required, it is possible to further improve the work efficiency.

  Furthermore, since the E-ring 26 is provided between the first engagement hole 21 and the second engagement hole 22 of the needle bar 20, even if the needle bar 20 falls, the E-ring 26 The second engagement hole 22 is restrained just before it descends to the clutch mechanism 60. For this reason, it is possible to avoid the vertical movement of the needle bar 20 at a position lower than normal due to the clutch mechanism 60 engaging with the second engagement hole 22. Or it becomes possible to prevent more effectively the damage of the sewing thing and the structure of a sewing machine located in the downward direction.

  Further, since the E-ring 26 having high versatility and high flowability is used as the locking portion of the needle bar 20, the productivity of the apparatus can be improved. In addition, the E-ring 26 can improve productivity because it is easy to mount and procure, and can be easily installed in an existing needle bar mechanism. Reproduction can be achieved.

However, the latching portion may have another configuration as long as it has a function of restricting at least the needle bar 20 from moving downward with respect to the needle bar holder 51. FIG. 10 is an explanatory view showing another example of the locking portion. FIG. 10A shows a screw 26 </ b> A provided on the needle bar 20 at the same position as the E-ring 26. FIG. 10B shows a split pin 26 </ b> B provided on the needle bar 20 at the same position as the E-ring 26. FIG. 10C shows a thrust collar 26 </ b> C that is a ring body provided on the needle bar 20 at the same position as the E-ring 26. FIG. 10D shows a step portion 26 </ b> D provided on the needle bar 20 at the same position as the E-ring 26.
Even with these configurations, substantially the same effect as the E-ring 26 can be obtained.

  In the above embodiment, the support of the needle bar 20 is supported by the needle bar rocking base (needle bar support frame 40) of the needle swing mechanism. However, the needle bar support is not necessarily required. The body only needs to support the needle bar so as to be movable up and down, and for example, the body may be fixed to a sewing machine frame.

It is a front view of the needle bar mechanism of the two needle sewing machine which is an embodiment of the invention, and shows the state which exists in the top dead center position in the two-needle holding state. 2A is a side view of the needle bar, and FIG. 2B is a front view. It is a front view of the needle bar mechanism of a two-needle sewing machine, and shows a state at the bottom dead center position in a two-needle holding state. It is sectional drawing of the needle bar mechanism by the cross section along the XZ plane while passing the centerline of one needle bar in the operation state of FIG. It is a perspective view of a clutch member. It is a perspective view of a stopper member. It is a front view of the needle bar mechanism of a two-needle sewing machine, and shows a state immediately after releasing the holding state of one needle bar. It is sectional drawing of the needle bar mechanism by the cross section which passes the centerline of one needle bar in the operation state of FIG. 7, and followed the XZ plane. It is a front view of the needle bar mechanism of a two-needle sewing machine, and shows a state where the holding state of one needle bar is released and moved to the bottom dead center. FIG. 10A is an explanatory view showing a needle bar equipped with a screw as another example of the locking part, and FIG. 10B is a needle bar equipped with a split pin as another example of the locking part. FIG. 10 (C) is an explanatory view showing a needle bar equipped with a thrust collar as another example of the locking part, and FIG. 10 (D) is another example of the locking part. It is explanatory drawing which shows the needle bar provided with the level | step-difference part.

Explanation of symbols

10 Needle bar mechanism of two-needle sewing machine 20 Needle bar 21 First engagement hole 22 Second engagement hole 26 E-ring (locking portion)
26A screw (locking part)
26B Split pin (locking part)
26C Thrust collar (locking part)
26D Stepped part (locking part)
40 Needle bar support frame (needle bar support)
50 Needle bar vertical movement mechanism 51 Needle bar holding 60 Clutch mechanism 61 Clutch member 61a Protrusion 66 Release pin 70 Stopper mechanism 71 Stopper member 71a Tip 80 Switching mechanism 81 Switching member 81a Abutting protrusion

Claims (4)

In the needle bar mechanism of a two-needle sewing machine having a one-needle stop function capable of selectively stopping the vertical movement of a pair of needle bars,
A pair of needle bars to hold the sewing needle;
A needle bar support that individually supports the pair of needle bars so as to be movable up and down;
A needle bar up-and-down moving mechanism for moving up and down each needle bar using a needle bar holding that individually holds the pair of needle bars;
A clutch mechanism capable of selectively switching the holding of each needle bar by the needle bar holding between a holding state and a released state;
A stopper mechanism that holds the needle bar held in the released state by the clutch mechanism on the needle bar support,
A drop-preventing locking portion for stopping the needle bar from dropping with respect to the needle bar hug, which is locked to the needle bar hug and held by neither the clutch mechanism nor the stopper mechanism. A needle bar mechanism for a two-needle sewing machine, characterized in that Each needle bar is provided with a first engagement hole with which the clutch mechanism is engaged and a second engagement hole with which the stopper mechanism is engaged,
An arrangement in which the stopper can be engaged with the second engagement hole by moving the locking portion to the top dead center of the needle bar holder, or a clutch mechanism is provided in the first engagement hole. 2. The needle bar mechanism of a two-needle sewing machine according to claim 1, wherein the needle bar mechanism is provided on each needle bar in an arrangement capable of being engaged. While arranging the stopper mechanism above the needle bar holding when located at the top dead center,
The needle bar mechanism of a two-needle sewing machine according to claim 2, wherein the locking portion is provided at a position between the first engagement hole and the second engagement hole.   The needle bar mechanism of a two-needle sewing machine according to claim 1, 2 or 3, wherein the locking portion is an E-ring equipped on the needle bar.

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