JP2010246841A - sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately and stably conduct thread cutting motion by making an initial position of a cam subordination body adjustable when it is fitted to a cam groove. <P>SOLUTION: A sewing machine is provided with a thread cutting device 30 equipped with a moving knife 31, a thread cutting drive mechanism 50 which applies the cutting motion to the moving knife, and a cloth feed mechanism 20 equipped with a vertical feed shaft 22 and a horizontal feed shaft 23, and is also provided with a supporting shaft 54 which is supported in a movable manner along the vertical feed shaft direction. A thread cutting cam 51 is installed on the vertical feed shaft 22 and on which the cam groove is formed on an end surface which is perpendicular to the vertical feed shaft 22 with a direction along the vertical feed shaft direction as a depth direction. A knife driving arm moves forward and backward along the vertical feed shaft direction to make the cam subordination body 52 switchable between a fitting position and an evacuating position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sewing machine including a thread trimming device.

FIG. 6 is a perspective view of a driving mechanism of a conventional sewing machine thread trimming device as seen from the bottom side of the sewing machine.
As shown in the figure, a conventional sewing machine reciprocally rotates with a fixed knife (not shown) and a moving knife (not shown) that reciprocates and cuts the sewing thread in cooperation with the fixed knife. A knife driving arm 101 that transmits a cutting operation to the moving knife, a cylindrical shaft 104 that is provided on a shuttle shaft 114 that is rotationally driven by a sewing machine motor and has a cam groove 102a formed on the outer periphery, and a thread cutting cam 102 Roller 103 as a follower that can be engaged with cam groove 102a, roller arm 104 that holds roller 103, and engagement position where roller 103 is engaged from roller arm 104 through the retracted position where it does not engage with cam groove 102a. When the clutch member 105 for applying the switching operation to the thread, the thread trimming solenoid 106 as the actuator that is the drive source for the switching operation of the clutch member 105, and the roller 103 are in the retracted position Roller arm 104 engaged with are those provided with a thread cutting device 100 and a stopper 107 to prohibit the rotation of the forward movement of the moving knife (e.g., see Patent Document 1).

7 is a side view of the drive mechanism of the thread trimming mechanism of FIG. 6 as viewed from the shuttle side, and FIG. 8 is a bottom view of the drive mechanism as viewed from below.
The knife drive arm 101 supports a roller arm 104 on its lower surface by a swing shaft extending in the left-right direction, and swings by displacement of the cam groove 102a of the thread trimming cam 102 via the roller 103 and the roller arm 104. It is possible to receive an action. The knife driving arm 101 is rotatably supported by a support shaft 108 on a base P fixed to the sewing machine frame on one end side, and the other end is connected to a moving knife via a link member 109. ing. The knife drive arm 101 is biased in one rotational direction (clockwise as viewed from below) by a torsion coil spring 110 as a return spring.
The thread trimming cam 102 is a so-called groove cam, and a cam groove 102a with which the roller 103 can be engaged is formed on the outer peripheral surface thereof. Such a thread trimming cam 102 is fixedly supported by a shuttle shaft 114 that rotates at a double speed of the main shaft by a sewing machine motor, and the vertical movement of the sewing needle and a thread trimming device are provided so as to prevent interference between the moving knife and the sewing needle. 100 can be synchronized.
The roller arm 104 is supported by the knife driving arm 101 so as to be swingable from the support shaft 104b, and the roller 103 provided at the swinging end moves toward and away from the thread trimming cam 102 by the swing. Thus, it is possible to switch between an engaging position where the cam groove 102a can be engaged and a retracting position where the cam groove 102a cannot be engaged. Since the roller arm 104 is supported by the knife driving arm 101, when the roller 103 is engaged with the cam groove 102a, the knife driving arm 101 rotates with the roller arm 104 according to the shape of the cam groove 102a. It has become. In order to prevent the moving knife and the sewing needle from interfering with each other as described above, the shape of the cam groove 102a is such that the moving knife moves back and forth after the sewing needle rises above the moving path of the moving knife. Is formed. Then, a reciprocating rotation operation is applied to the moving knife through the link member 109 to cut the sewing thread. The roller arm 104 is urged by a torsion coil spring 111 as a return spring in a swinging direction, which is a retracted position where the roller 103 is not normally engaged with the cam groove 102a. On the proximal end side of the roller arm 104, a pressing portion 104a to which a pressing force for moving the roller 103 to the engagement position against the torsion coil spring 111 is input.

The clutch member 105 is pivotally supported on the sewing machine frame by a support shaft 112 in the middle thereof, and one end portion thereof is provided with an input portion 105a that applies a pressing operation to the pressing portion 104a of the roller arm 104. A thread trimming solenoid 106 is connected to the end.
The clutch member 105 is provided with a torsion coil spring 113 as a return spring on the support shaft 112, and urges the input portion 105 a in the clockwise direction to separate it from the pressing portion 104 a of the roller arm 104. The thread trimming solenoid 106 rotates the clutch member 105 in a direction in which the input portion 105 a presses the pressing portion 104 a of the roller arm 104 against the elastic force of the torsion coil spring 113.
Further, when the roller 103 is in the retracted position, the knife driving arm 101 is in a fixed position holding state in which the roller arm 104 is fitted into a concave portion 107a of a stopper 107, which will be described later, and the rotating movement of the moving knife is prohibited. When the member 105 rotates the roller arm 104, the fitting state of the roller arm 104 with respect to the stopper 107 can be released. That is, the clutch member 105 has a function of imparting a switching operation from the retracted position to the engaged position of the roller 103 and releasing the fixed position holding state of the knife driving arm 101. In addition, when the roller 103 is in the retracted position as described above, the movement of the moving knife is prevented when the sewing thread is not sufficiently cut by the moving knife as described in Patent Document 1 described above. In addition, when the operator takes out the cloth, the moving knife is pulled out to the needle drop position by being pulled by the uncut thread.

  With this configuration, the conventional sewing machine operates in a direction in which the thread trimming solenoid 106 pulls the clutch member 105 when performing the thread trimming, whereby the input unit 105a presses the pressing unit 104a of the roller arm 104, and the roller arm 104a. The roller 103 is fitted into the cam groove 102a of the thread trimming cam 102. Further, the roller arm 104 is released from the concave portion 107a of the stopper 107 and the fixed position holding state is released, and the roller arm 104 and the knife driving arm 101 rotate according to the displacement of the cam groove 102a. As a result, the moving knife reciprocates through the link member 109, selects the yarn and cuts only the necessary yarn. The stopper 107 includes an abutting end portion 107b that protrudes upward adjacent to the concave portion 107a, and abuts against the lower surface of the roller arm 104 while the roller 103 is fitted in the cam groove 102a. 103 is held so as not to be removed from the cam groove 102a. The cam groove 102a is formed to return the roller arm 104 to the position of the concave portion 107a via the roller 103 when the reciprocating rotation of the moving knife is completed. The roller arm 103 is fitted into the concave portion 107a of the stopper 107 and returned to the fixed position holding state. The thread trimming solenoid 106 is controlled so as to push the clutch member 105 back to the original position when the roller arm 104 is supported by the contact portion 107b of the stopper 107.

No. 03-027582

  However, the drive mechanism of the thread trimming device of the sewing machine is provided on the shuttle shaft where the thread trimming cam 102 rotates at a double speed of the upper shaft, and therefore the thread trimming device is only in a period during which the upper shaft rotates by 180 °. In order to perform stable thread trimming using the thread trimming cam 102 that performs high-speed rotation in this way, there is a problem that the rotational speed of the sewing machine motor must be sufficiently reduced. It was.

Further, as described above, when the roller 103 moves in the radial direction with respect to the cam groove 102a formed on the outer peripheral surface of the thread trimming cam 102, the roller 103 enters when the roller 103 enters or leaves the cam groove 102a. Therefore, it is necessary to form the cam groove 102a so as not to be displaced in a certain section where the withdrawal is performed. This is because if the section that does not cause such a displacement is not provided, the roller 103 is displaced with respect to the cam groove 102a and cannot enter, or conversely, it cannot be retracted.
However, when the thread trimming cam rotates at a high speed twice that of the upper shaft as in the above-described conventional sewing machine, in order to achieve stable entry / exit of the roller 103, a non-displacement section is sufficient in the cam groove 102a. As a result, it has been difficult to freely adjust the operation timing of thread trimming by changing the shape of the cam groove 102a. For example, by delaying the timing of thread trimming and bringing it closer to the top dead center of the balance, the amount of thread pulled by the balance after cutting can be reduced, so the length of the remaining thread of the sewing needle (from the sewing needle to the cutting end) The thread length to the thread) can be sufficiently secured, and the sewing thread can be prevented from coming off from the sewing needle at the start of the next sewing, and the seam can be formed more reliably. There was a problem that it was difficult to make adjustments.

Further, the conventional sewing machine is provided with a vertical feed shaft that gives vertical movement to the feed dog and a horizontal feed shaft that gives forward and backward movement to the feed dog, adjacent to the hook shaft 114 in parallel. Since the three shafts are provided adjacent to each other in the front-rear direction, a thread trimming drive mechanism must be disposed in either the upper region or the lower region of these three shafts. However, since the hook and the hook shaft cannot be arranged away from the needle plate, a large part such as a thread trimming solenoid (not limited to the solenoid, other actuators are used in the upper area of the three shafts. It is impossible to secure a space for disposing the drive mechanism including the same), and it is necessary to dispose the drive mechanism in a region below the three shafts.
On the other hand, the thread trimming device to which the operation is applied from the drive mechanism must cut the sewing thread between the shuttle and the throat plate, and therefore needs to be arranged upward in the sewing machine bed portion.
Therefore, the drive mechanism and the thread trimming device must be arranged separately on the lower side and the upper side with the three axes as the boundary, so the upper part of the transmission path from the drive mechanism to the thread trimming device In the conventional sewing machine, for example, as shown in FIG. 6, for example, a rod-shaped transmission body 115 extending in the vertical direction between the female drive arm 101 and the link member 109 is required. And the swinging motion of the knife driving arm 101 in the left-right direction is transmitted to the link member 109. Alternatively, a transmission body 115 along the vertical direction is provided between the link member 109 and the thread trimming device to transmit the left / right motion.
However, if the movement along the horizontal plane, such as the movement in the left-right direction, is transmitted through the transmission body 115 oriented in the vertical direction, the force is transmitted in the direction perpendicular to the longitudinal direction while maintaining the upright state. Therefore, the transmission body 115 is likely to be inclined due to the fall, and as a result, the operation of the thread trimming device is delayed, or the moving knife does not reciprocate with the original operation amount. There was a problem of causing defects.

  An object of the present invention is to execute the thread trimming operation appropriately and stably.

The invention described in claim 1
A thread trimmer provided with a moving knife for cutting a sewing thread by reciprocating rotation;
A thread trimming drive mechanism that applies a cutting operation to the moving knife of the thread trimming device using a sewing motor;
A cloth feed mechanism comprising a feed dog, a vertical feed shaft that rotates once in the same cycle as the upper shaft and imparts vertical motion to the feed dog, and a horizontal feed shaft that imparts longitudinal motion to the feed dog,
A cloth feed mechanism comprising a feed dog, a vertical feed shaft that imparts vertical motion to the feed dog, and a horizontal feed shaft that imparts longitudinal motion to the feed dog,
The thread trimming drive mechanism is
A thread trimming cam that is rotationally driven by a sewing machine motor;
A knife drive arm that imparts a cutting action to the moving knife by performing a pivoting action;
A cam follower which is provided on the knife driving arm and applies a turning motion to the knife driving arm by fitting into a cam groove of the thread trimming cam;
In a sewing machine comprising: an actuator that applies a position switching operation of the female drive arm to a fitting position where the cam follower is fitted into a cam groove of the thread trimmer cam and a retracted position where the cam follower is not fitted;
It is supported by a sewing machine frame so as to be movable along the vertical feed shaft direction, and includes a support shaft that rotatably supports the knife driving arm,
The thread trimming cam is provided on the vertical feed shaft, and the cam groove is formed on an end surface perpendicular to the vertical feed shaft with a direction along the vertical feed shaft direction as a depth direction.
The female drive arm is capable of switching the cam follower (52) between the fitting position and the retracted position by moving forward and backward along the vertical feed axis direction.

The invention according to claim 2 has the same configuration as the invention according to claim 1,
The support shaft is disposed below the vertical feed shaft,
The female drive arm has a rotating end portion extending from the support shaft to above the vertical feed shaft.

  The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and the thread trimming drive mechanism includes a link body that transmits operation from the knife driving arm to the thread trimming apparatus. The link body has spherical bearings at both ends thereof.

The invention described in claim 4 has the same configuration as that of the invention described in claim 3,
The link body (58) is disposed between the shuttle shaft (11) and the sewing machine bed upper surface (2a) so as to intersect the shuttle shaft (11).
The link body (58) has one end connected to the female drive arm and the other end connected to the L-shaped rotation link (64, 65).
A moving knife drive link (61) is arranged so as to intersect the link body, one end side is connected to the L-shaped rotating link, and the other end side is connected to the moving knife.

The invention according to claim 5 has the same configuration as the invention according to claim 4,
A stop pad (60) that can be moved forward and backward with respect to the sewing machine frame and can contact the link body (58) or the L-shaped rotary link (64, 65);
The link body (58) or the L-shaped rotation link (64, 65) is provided with a spring (68) that biases the stopper so as to abut against the stopper.
The invention described in claim 6 has the same configuration as the invention described in claim 4 or 5, and
The L-shaped rotation link is configured to include two L-shaped rotation links (64, 65) that are rotatably supported by the support shaft (67) and are disposed so as to partially overlap each other.
One L-shaped rotation link (64) is connected to the link body and the other L-shaped rotation link (65) is connected to a moving knife drive link.
A connection screw (66) for adjusting the position of the moving knife by adjusting the connection position of the two L-shaped rotation links is provided.

  According to the first aspect of the present invention, since the thread trimming cam is supported by the vertical feed shaft of the feed dog, one rotation is performed at the same cycle as the upper shaft that drives the vertical movement of the sewing needle of the sewing machine. In addition, since high-speed rotation is not performed at double speed, rotation by 360 ° on the upper shaft can be used to drive the thread trimming device, and thread trimming can be performed with the sewing machine motor rotating at a higher speed than before. It becomes.

  Further, since the thread trimming cam rotates at the same speed as the upper shaft, even if a non-displacement section for fitting the cam follower into the cam groove is formed in the cam groove, a displacement section for imparting a thread cutting operation is provided. Since it becomes possible to ensure sufficiently, the operation timing of thread trimming can be freely adjusted.

  In the first aspect of the invention, since the thread trimmer cam is not provided on the shuttle shaft, it is possible to widen the periphery of the shuttle shaft located at the center in the sewing machine bed.

  In the invention according to claim 2, the support shaft is disposed below the vertical feed shaft (closer to the bottom of the sewing machine), and the rotating end portion of the knife driving arm extends upward from the vertical feed shaft. Even when the actuator of the drive mechanism is placed under each feed shaft of the hook shaft or cloth feed device and the thread trimmer is placed above each shaft, the knife drive arm is given a position switching operation from the actuator. In addition, it is possible to apply the motion of the moving knife from the knife driving arm to the thread trimmer.

According to invention of Claim 3, 4, it becomes a planar structure compared with the conventional thread trimming mechanism.
Further, the rotational movement of the vertical feed shaft is transmitted to the thread trimming mechanism via the thread trimming cam, the knife driving arm, the link body, and the L-shaped rotation link. At this time, the movement of the link body in the front-rear direction is converted into the movement in the left-right direction.

  According to the fifth aspect of the present invention, the initial position when the cam follower is fitted into the cam groove can be adjusted, so that the thread trimming operation becomes smooth.

  According to the sixth aspect of the present invention, the position of the moving knife can be adjusted with a simple structure.

It is the perspective view which looked at the sewing machine from the lower part in the state where the bottom plate was removed. It is the bottom view which looked at the thread trimming device from the lower part. It is sectional drawing along the VV line in FIG. It is an enlarged bottom view which shows the surrounding structure of a knife drive arm. It is a bottom view of a knife position adjustment body. It is the perspective view which looked at the drive mechanism of the conventional thread trimming device of a sewing machine from the bottom side of the sewing machine. It is the side view which looked at the drive mechanism of the thread trimming mechanism from the shuttle side. It is the bottom view which looked at the drive mechanism of a thread trimming mechanism from the bottom.

(Outline of sewing machine)
A sewing machine 10 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the sewing machine 10 as viewed from below with the bottom plate removed.
The sewing machine 10 includes a needle up / down movement mechanism (not shown) that moves the sewing needle up and down, a hook mechanism (not shown) that captures the upper thread passed through the sewing needle and entangles the lower thread to form a seam, A cloth feed mechanism 20 that appears and disappears from an opening formed in the needle plate and feeds a sewing product in a predetermined cloth feed direction, a thread trimmer 30 that cuts an upper thread and a lower thread, and a movement of the thread trimmer 30 A thread trimming drive mechanism 50 that imparts a cutting operation to the knife 31 and a sewing machine frame (only the sewing machine bed 2 is shown) that supports or stores the above-described components are provided.
In the following description, in a state where the sewing machine 10 is installed on the horizontal plane, the horizontal direction that coincides with the cloth feeding direction is the X-axis direction, the horizontal direction that is orthogonal to the X-axis direction is the Y-axis direction, and the vertical direction. The vertical direction is referred to as the Z-axis direction. Also, in one direction in the Z-axis direction, the upper side is “up”, the lower side is “down”, the direction in which the operator is positioned with respect to the sewing machine in one direction in the X-axis direction is “rear”, and the opposite side is “ As viewed from the operator side in one direction in the Y-axis direction, the left side is referred to as “left” and the right side is referred to as “right”.

(Needle vertical movement mechanism)
The needle up-and-down movement mechanism is supported on the surface side of the sewing machine arm portion (not shown) in the sewing machine frame so as to be movable up and down and holds the sewing needle at the lower end, and a drive source for the vertical movement of the needle bar This is composed of a sewing machine motor, a main shaft that is rotationally driven by the sewing motor, and a crank mechanism that converts the rotational driving of the main shaft into vertical movement and transmits it to the needle bar, and is similar to a known one.

(Hook mechanism)
The hook mechanism is a hook mechanism using a so-called full-rotation hook. The hook mechanism rotates the unillustrated full-rotation hook inside the sewing machine bed 2 and below the needle plate, and the full-rotation outer hook. The hook shaft 11 is provided and is similar to a well-known one. The shuttle shaft 11 is supported inside the sewing machine bed portion 2 so as to be rotatable along the Y-axis direction. The shuttle shaft 11 is given a rotational force from the sewing machine motor so as to rotate at a double speed of the main shaft (also referred to as an upper shaft).
The shuttle shaft 11 rotates in conjunction with the upper shaft, and forms a seam in cooperation with the sewing needle. The shuttle shaft 11 is disposed along the Y-axis direction (also referred to as the vertical feed shaft direction).

(Cloth feed mechanism)
The cloth feed mechanism 20 includes a feed base 21 having sawtooth feed teeth (not shown) protruding from an opening of a needle plate on its upper surface, a vertical feed shaft 22 that is rotationally driven by a sewing machine motor, and a sewing machine motor. A horizontal feed shaft 23 that reciprocates, an eccentric cam 24 that is fixedly mounted on the vertical feed shaft 22, one end is connected to the eccentric shaft of the eccentric cam 24, and the other end is connected to the rear end of the feed base 21. A vertical feed rod 25 to be connected and a horizontal feed arm 26 that is fixedly supported by the horizontal feed shaft 23 and swings in the front-rear direction at a swing end connected to the feed base 21 are provided. The vertical feed shaft 22 is connected via a belt (not shown) so that when the main shaft makes one revolution, the vertical feed shaft 22 also makes one revolution with the same cycle as the main shaft (also referred to as the upper shaft).

The vertical feed shaft 22 is disposed rearward (operator side) of the hook shaft 11 inside the sewing machine bed portion 2 and is supported rotatably in a state along the Y-axis direction. The vertical feed shaft 22 is fixedly equipped with a toothed driven pulley (not shown) so that torque is applied via a toothed timing belt from the main pulley provided on the main shaft of the needle vertical movement mechanism. It has become. That is, the vertical feed shaft 22 is configured to be rotationally driven by the sewing machine motor via the main shaft, and the transmission ratio is set so as to rotate at the same speed as the main shaft.
When the vertical feed shaft 22 performs full rotation, the vertical feed rod 25 transmits only the vertical movement component of the circular motion performed by the eccentric shaft of the eccentric cam 24 to the feed base 21, and the feed base 21 moves the sewing needle up and down. It moves up and down at the same cycle as the movement.
Incidentally, the hook shaft 11 described above is configured to be rotated by the vertical feed shaft 22 through the speed increasing gear train, and the rotary motion is imparted at a double speed of the vertical feed shaft 22. ing.

The horizontal feed shaft 23 is disposed closer to the front than the shuttle shaft 11 inside the sewing machine bed portion 2 and is rotatably supported in a state along the Y-axis direction. The above-described vertical feed shaft 22 is provided with an eccentric rod that holds an eccentric cam (not shown) fixedly mounted on the vertical feed shaft 22, and the horizontal feed shaft 23 is fixedly equipped with a driven arm (not shown). Yes. Then, the end of the eccentric rod that is not on the eccentric cam side and the swinging end of the driven arm are connected, so that a reciprocating rotation operation is imparted from the vertical feed shaft 22 to the horizontal feed shaft 23. ing. That is, the horizontal feed shaft 23 is configured to be reciprocally rotated by the sewing machine motor via the vertical feed shaft 22 and the main shaft, and has the same reciprocating rotation cycle as the rotation cycle of the vertical feed shaft 22. Is set to the transmission ratio.
As a result, the feed table 21 is provided with reciprocating vertical movement and reciprocating back-and-forth movement in the same cycle, and by appropriately adjusting these phases, the feed table 21 performs an elliptical motion along the cloth feeding direction. It is like that. The feed dog of the feed base 21 protrudes upward from the opening of the needle plate in the upper section of the elliptical motion, and the elliptical rotation direction of the feed base 21 so that the moving direction coincides with the cloth feed direction. Is adjusted, and it is possible to feed a needle-plate-like workpiece in a predetermined feeding direction.

(Thread trimming device)
FIG. 2 is a bottom view of the thread trimming device 30 as viewed from below.
As shown in the figure, the thread trimmer 30 rotates the main body frame 32, the fixed knife 33 fixedly supported on the main body frame 32, the moving knife 31 rotatably supported on the main body frame 32, and the moving knife 31. And an operating arm 34.
The moving knife 31 is pivotally supported by the step screw 35 so as to be rotatable with respect to the main body frame 32. The two-dot chain line shows the standby position, and the solid line shows the last retracted position in the reciprocating rotation. . During sewing, the moving knife 31 is in the position of the two-dot chain line and is separated from the illustrated needle drop position S. At the time of cutting, the thread to be cut is distributed by retreating to the solid line position, and the thread is advanced again to the position of the two-dot chain line, and the sewing thread is cut in cooperation with the fixed knife 33.
The fixed knife 33 is provided with a blade part 33a, and when the moving knife 31 moves backward, the thread sandwiched between the blade part 31a of the moving knife 31 and the blade part 33a of the fixed knife 33 is cut. It has become.

The operating arm 34 is pivotally supported with respect to the main body frame 32 by a step screw 36 at an intermediate position in the longitudinal direction, and one end thereof is connected to a second link body 61 of a thread trimming drive mechanism 50 described later. Has been. Further, a groove-shaped notch 34 a into which an engaging convex portion 31 b provided on the upper surface of the moving knife 31 is fitted is formed at the other end of the operating arm 34, and as the operating arm 34 rotates. Thus, the moving knife 31 can be rotated. In addition, since the notch 34a is formed in a groove shape in this way, the engaging convex part 31b can move inside the notch 34a, and the difference in the turning radius between the operating arm 34 and the moving knife 31 is possible. Can be tolerated.
With this structure, in the thread trimming device 30, the second link body 61 of the thread trimming drive mechanism 50 moves forward and backward in the right direction and the left direction, so that the end on the notch 34a side of the operating arm 34 is leftward. The thread cutting operation can be performed by rotating rightward and then rotating the moving knife 31 in the same direction.

(Thread trimming drive mechanism)
FIG. 3 is a cross-sectional view taken along line VV in FIG.
As shown in FIGS. 1 and 3, the thread trimming drive mechanism 50 includes a thread trimming cam 51 fixedly mounted on the vertical feed shaft 22 and a follower body that can be engaged with a cam groove 51 a of the thread trimming cam 51. A roller 52, a knife driving arm 53 that holds the roller 52 by the input unit 53a and reciprocates to transmit the cutting operation to the moving knife 31, a support shaft 54 that supports the knife driving arm 53, and a knife driving arm 53 Through the clutch member 55 for applying the switching operation from the retracted position where the roller 52 is not fitted into the cam groove 51a to the fitting position where the roller 52 is fitted, and the thread trimming solenoid 56 as an actuator which is a drive source of the switching operation of the clutch member 55. A first stopper 57 that engages with the knife drive arm 53 when the roller 52 is in the retracted position and prohibits the forward movement of the moving knife 31, and one end of the output part 53b of the knife drive arm 53. Linking A first link body 58 (also referred to as a link body), a female position adjustment body 59 as a female position adjustment means connected to the other end of the first link body 58, and a female position adjustment body 59. A position-adjustable second stopper 60 (also referred to as a stopper) that stops the knife drive arm 53 at one end of the moving knife 31 on the movement start side in the rotation range, a knife position adjusting body 59, and a thread A second link body 61 (also referred to as a moving knife drive link) that connects the operating arm 34 of the cutting device 30 is provided.

The thread trimming cam 51 is formed in a substantially disk shape when viewed from the Y-axis direction, and is fixedly supported by the vertical feed shaft 22 located at the center thereof, and is formed on the right end surface perpendicular to the vertical feed shaft 22. A cam groove 51a having an axial direction as a depth direction is formed.
The cam groove 51a has a non-displacement section that is a fixed distance from the vertical feed shaft 22 that is the center of rotation and a displacement section that returns to the same distance as the non-displacement section after gradually approaching the vertical feed shaft 22 that is the center of rotation. Only the displacement section is connected to the endless ring. When the vertical feed shaft 22 has an axial angle at which the roller 52 faces the non-displacement section, the roller 53 enters or leaves the cam groove 51a. Further, when the roller 52 that has entered the cam groove 51 a is present in the displacement section, a displacement in the substantially Z-axis direction is input from the cam groove 51 a and the displacement is transmitted to the knife drive arm 53.

FIG. 4 is an enlarged bottom view showing the configuration around the knife drive arm 53.
As shown in FIGS. 1, 3, and 4, the knife driving arm 53 includes a cylindrical base portion 53 c that is fixed to the support shaft 54, and an input portion 53 a that extends outward in the rotational radial direction from the base portion 53 c. An output portion 53b extending in a direction different from the input portion 53a from the base portion 53c in the rotational radius direction, and an input portion 53a and an output portion 53b in the rotational radial direction from the base portion 53c. And a position restricting projection 53d extending in a different direction. That is, in a state where the knife driving arm 53 is supported by the support shaft 54, the position restricting projection 53d extends substantially downward, the input portion 53a extends generally forward in the X-axis direction, and the output portion 53b extends substantially upward.
Further, the input portion 53a, the base portion 53c, and the position regulating projection 53d of the knife drive arm 53 are positioned below all of the vertical feed shaft 22, the horizontal feed shaft 23, and the shuttle shaft 11, and the output portion 53b is fed up and down. All of the shaft 22, the horizontal feed shaft 23, and the shuttle shaft 11 are positioned above.
Since the inside of the sewing machine bed portion 2 has three vertical feed shafts 22, horizontal feed shafts 23, and shuttle shafts 11 arranged in parallel, these shafts 22, 23, and 11 are used as a boundary to the lower area. Although divided into the upper area, the knife drive arm 53 extends from the lower side to the upper side of the shafts 22, 23, 11 as described above. A configuration (clutch member 55, thread trimming solenoid 56, first stopper 57, etc.) used to engage with or release the thread trimming cam 51 is disposed in the lower area, and the knife 31 moves from the knife driving arm 53. It is possible to arrange all the configurations (the first link body 58, the female position adjustment body 59, the second link body 61, etc.) that transmit the operation until the upper area.

Furthermore, since the knife drive arm 53 includes an input portion 53a and an output portion 53b that are rotating ends extending in two directions with respect to the support shaft 54, the knife drive arm 53 has a bell crank structure. With this structure, when a rotation operation is input from the roller 52 provided in the input unit 53a according to the cam groove 51a, the output unit 53b also performs a rotation operation, and the arc generated by the rotation of the output unit 53b. The first link body 58 connected so as to be along the tangential direction of the movement trajectory can be given an advancing / retreating movement operation along the longitudinal direction (roughly the X-axis direction).
Further, the knife driving arm 53 is formed with a protrusion 53e along the Y-axis direction (also referred to as the vertical feed axis direction). The protrusion 53e is provided with a through hole, and a later-described support shaft 54 is inserted into the through hole. Then, the knife driving arm 53 is fixed to the support shaft 54 by the screw 70.
Instead of this, it is easily conceivable to provide two E-rings or two thrust collars on the support shaft 54 to support both ends of the knife drive arm 53 in the Y-axis direction. It is also conceivable that a step portion is provided on one end side of the support shaft 54 and the female drive arm 53 is attached, and then the other end side is locked with an E-ring or the like. As described above, the knife driving arm 53 may be rotatably supported, and the knife driving arm 53 may be moved together in the Y axis direction as the support shaft 54 moves in the Y axis direction.

Both ends of the support shaft 54 are sewing machines so that the sewing bed portion 2 can advance and retract along the Y-axis direction (also referred to as the vertical feed axis direction) and rotate around the Y-axis. Supported by the frame. The support shaft 54 only needs to be able to advance and retract along the Y-axis direction by a collar, a bearing, or the like provided on the sewing machine frame.
Accordingly, the knife driving arm 53 can perform the forward / backward movement and the rotation operation similar to the support shaft 54. Further, the support shaft 54 is provided with a flange portion 54a, and the support shaft 54 and the female drive arm 53 are always pressed rightward by a pressing spring 62 via the flange portion 54a.
On the other hand, the first stopper 57 has a concave portion 57a formed on the right side of the position regulating projection 53d, and is adjacent to the front side of the concave portion 57a and maintains the state where the roller 52 is engaged with the cam groove 51a. For this purpose, an engagement maintaining projection 57b that is convex to the left is formed.
As described above, since the knife drive arm 53 is always pressed rightward by the pressing spring 62, the state where the position restricting protrusion 53d is fitted in the recess 57a that is recessed rightward is maintained. It has become. When the position regulating projection 53d is pressed to the left against the pressing spring 62 by the thread trimming solenoid 56 and the clutch member 55, it can be detached from the recess 57a, and further, the input of the female drive arm 53 The roller 52 held by the arm 53a is fitted into the cam groove 51a, and the knife driving arm 53 is rotated by the displacement section of the cam groove 51a so that the position restricting projection 53d moves forward. Then, the engagement maintaining projection 57b is in contact with the position restricting projection 53d immediately to the right (the state indicated by the two-dot chain line in FIG. 4), and the female drive arm 53 is not affected by the pressing force of the pressing spring 62. The roller 52 does not move to the right, and the roller 52 is maintained so as not to be detached from the cam groove 51a.

  As described above, the thread trimming solenoid 56 and the clutch member 55 are disposed in the lower area. The clutch member 55 is pivotally supported by the sewing machine bed portion 2 so as to be rotatable about the Z axis at an intermediate portion in the longitudinal direction, and one of the rotating end portions is rotated counterclockwise when viewed from the bottom. The contact portion 55a is configured to come into contact with the position restricting projection 53d of the knife driving arm 53 to release the holding state by the first stopper 57. Further, adjacent to the contact portion 55a, there is a yarn tension releasing portion 55b connected to the releasing wire 12 for releasing the yarn tension applying state by an unillustrated upper yarn tensioning device. The yarn tension releasing portion 55b is operated so as to release the yarn tension at the same time when the contact portion 55a rotates in a direction to release the holding state of the position regulating projection 53d.

A plunger of a thread trimming solenoid 56 is connected to the vicinity of the other rotation end of the clutch member 55 so that the rotation of the clutch member 55 is biased. When the thread trimming solenoid 56 is not driven, the plunger is in a protruding state, and when it is driven, the plunger is in a retracted state to urge the clutch member 55 to rotate counterclockwise as viewed from the bottom.
Further, the other rotating end of the clutch member 55 is connected to a connecting link member 63 for pulling the hook thread presser 13 for preventing rotation of the bobbin accommodated in the inner hook of the hook mechanism into the rotation blocking state. ing. Thus, when the thread trimming solenoid 56 rotates the clutch member 55 counterclockwise as viewed from the bottom, the hook thread presser 13 is simultaneously rotated to prevent the bobbin from rotating, and the bobbin thread is cut during thread trimming. Can be prevented from being unsuccessfully cut out from the bobbin.

  FIG. 5 is a bottom view of the knife position adjusting body 59. The female position adjusting body 59 includes first and second rotating pieces 64 and 65 (also referred to as a plurality of L-shaped rotating links) overlapped with each other, and these are integrally connected by a connecting screw 66. At the same time, the two rotating pieces 64 and 65 are pivotally supported around the Z axis by one step screw 67 at the same time. The first turning piece 64 includes a turning end portion that extends generally to the left in the Y-axis direction, and the turning end portion is connected to the end portion of the first link body 58. The second rotating piece 65 includes a rotating end portion that extends generally forward in the X-axis direction, and the rotating end portion is connected to the end portion of the second link body 61. With this structure, the female position adjustment body 59 has a bell crank structure. That is, when a rotation operation is applied to the first rotation piece 64 from the advance / retreat operation of the first link body 58 along the X-axis direction, the step screw 67 (also referred to as a support shaft) is used as a support shaft. The second rotating piece 65 is also rotated in the same direction, and can be given an advance / retreat operation to the second link body 61 generally along the Y-axis direction.

  Further, the first rotating piece 64 (also referred to as a first L-shaped rotating link) is biased counterclockwise by a tension spring 68 as viewed from the bottom. A second stopper 60 is provided at the counterclockwise rotation destination of one rotation piece 64, and the state where the first rotation piece 64 is pressed against the second stopper 60 is maintained. It is like that. The rotation angle at which the first rotation piece 64 is held by the second stopper 60 is a position at which the roller 52 can enter the non-displacement section of the cam groove 51a via the first link body 58. Thus, the rotation angle for maintaining the rotation angle of the knife drive arm 53. The second stopper 60 is composed of a headless screw (head screw) 60a and a nut 60b for fixing the position of the screw. By screwing the screw 60a and fastening with the nut 60b, The stop angle of one rotating piece 64 can be adjusted. That is, the second stopper 60 and the tension spring 68 function as an initial position adjusting mechanism for the roller 52 (cam follower) that can adjust the initial position of the roller 52.

Further, the second rotating piece 65 (also referred to as a second L-shaped rotating link) is connected to the first rotating piece 64 by a connecting screw 66 through an elongated hole 65a. Is loosened, the elongated hole 65a allows the first turning piece 64 and the second turning piece 65 around the stepped screw 67 to be mutually rotated. When the initial position adjustment of the roller 52 is performed by the above-described second stopper 60 in the fastening state of the connection screw 66, the entire knife position adjusting body 59 is rotated and the standby position of the moving knife 31 is changed. In such a case, the standby position of the moving knife 31 is adjusted while appropriately adjusting the initial position of the roller 52 by loosening the connecting screw 66 and adjusting only the second rotating piece 65. It becomes possible to adjust to an appropriate position.
As described above, in the present embodiment, the first rotating piece 64 and the second rotating piece 65 are used. Instead of this, it is easy to think of using a single rotating piece to connect a link body 58 to one end side and a moving knife drive link 61 (described later) to the other end side to provide the same function. It is done.
Further, although the stopper 60 is configured to contact the first rotating piece 64, it can be easily configured to contact the link body 58 described later.

The link body 58 connects the knife driving arm 53 and the first rotating piece 64 (also referred to as a first L-shaped rotating link) of the knife position adjusting body 59, and connects the output portion 53 b of the knife driving arm 53. It has a function of transmitting an advancing / retreating operation substantially along the X-axis direction to the rotating end portion of the first rotating piece 64. By the way, the output portion 53b of the knife drive arm 53 is displaced in the X-axis direction and the Z-axis direction by the rotation operation, and the first rotation piece 64 is moved in the X-axis direction and the Y-axis direction by the rotation operation. Displacement occurs. Further, the position of the knife drive arm 53 is also switched along the support shaft 54 (Y-axis direction). As described above, since both ends of the first link body 58 are displaced in all directions, the both ends are connected to the knife driving arm 53 and the first rotating piece 64 through the spherical bearings 58a and 58b, respectively. Has been. Thereby, even when displacement occurs in each direction at both ends, it is possible to smoothly transmit the operation.
The link body 58 is substantially orthogonal to the shuttle shaft 11 and is disposed between the shuttle shaft 11 and the sewing machine bed upper surface 2a.

  On the other hand, a second link body (also referred to as a moving knife drive link) 61 connects the second rotating piece 65 of the knife position adjusting body 59 and the operating arm 34 of the thread trimming device 30 to the second rotation. The moving piece 65 has a function of transmitting the advancing / retreating operation substantially along the Y-axis direction to the rotating end of the first operating arm 34. Since both the second rotating piece 65 and the operating arm 34 are displaced by the rotation in the X-axis direction and the Y-axis direction, they coincide with each other. I don't need it.

(Thread cutting operation of sewing machine)
In the sewing machine 10 having the above-described configuration, when thread trimming is performed, a predetermined main shaft angle (timing at which interference between the sewing needle and the moving knife 31 does not occur, for example, the sewing needle is adjusted) The thread trimming solenoid 56 is actuated in the direction of pulling the clutch member 55 at the time when the sewing product comes off. Thereby, the hook thread presser 13 is actuated via the connecting link member 63, and the rotation of the bobbin accommodated in the inner hook of the hook mechanism is prevented.
Further, the thread tension releasing portion 55b of the clutch member 55 pulls the release wire 12 and releases the thread tension device for the upper thread.
Further, the contact portion 55a of the clutch member 55 presses the position restricting projection 53d of the knife driving arm 53 to the left and moves it to the outside of the recess 57a, and moves the roller 52 in the cam groove 51a of the thread trimming cam 51. To enter. At this time, the cam groove 51a has a non-displacement section at the entry position of the roller 52, and the second stopper 60 is adjusted in advance so that the roller 52 can enter the non-displacement section.
Then, the thread trimming cam 51 rotates as the vertical feed shaft 22 rotates, and when the roller 52 reaches the displacement section, the knife driving arm 53 is rotated counterclockwise as viewed from the right side, and the first link body. Via 58, the knife position adjusting body 59 is rotated clockwise in a bottom view. As a result, the connecting end portion of the operating arm 34 of the thread trimming device 30 is rotated to the right via the second link body 61 so that the moving knife 31 is moved backward from the standby position (see FIG. 2). Move from the position of the moving knife of the two-dot chain line to the position of the solid line). As a result, the moving knife 31 passes through the needle drop position and selects the thread to be cut.
Further, when the thread trimming cam 51 rotates, the roller moves so as to return to the latter half of the displacement section, that is, the non-displacement section. As a result, the knife driving arm 53 rotates clockwise in a right side view, The female position adjusting body 59 rotates counterclockwise through the one link body 58 in a bottom view. As a result, the connecting end of the operating arm 34 of the thread trimming device 30 is rotated to the left via the second link body 61 so that the moving knife 31 is advanced from the retracted position toward the standby position. (Move from the moving knife position of the solid line in FIG. 2 to the position of the two-dot chain line). As a result, the moving knife 31 passes through the needle drop position again, and further carries the thread to be cut to the blade part 33a of the fixed knife 33 to execute cutting.

(Effect of embodiment)
In the sewing machine 10, since the thread trimming cam 51 is supported by the vertical feed shaft 22, the sewing machine 10 performs one rotation at the same cycle as the upper shaft that drives the vertical movement of the sewing needle of the sewing machine 10. Since high-speed rotation is not performed at double speed, rotation by 360 ° of the upper shaft can be used to drive the thread trimming device 30, and thread trimming can be performed with the sewing machine motor rotating at a higher speed than before. It becomes.
Further, since the thread trimming cam 51 rotates at the same speed as the upper shaft, even if a non-displacement section for fitting the roller 52 into the cam groove 51a is formed in the cam groove 51a, a displacement that gives a thread cutting operation. Since a sufficient section can be secured, the operation timing of thread trimming can be freely adjusted. Therefore, for example, it is possible to delay the thread trimming timing to ensure a sufficient length of the remaining thread of the sewing needle, thereby preventing skipping and improving the sewing quality.
Further, since the sewing machine 10 does not include the thread trimming cam 51 on the shuttle shaft 11, the periphery of the shuttle shaft 11 located at the center in the sewing machine bed portion 2 can be widened, and the space can be used for other purposes ( For example, it can be used for oil tanks and the like.

Further, in the sewing machine 10, the knife driving arm 53 is pivotally supported by a support shaft 54 that is located closer to the bottom of the sewing machine (lower side) than the vertical feed shaft 22, the horizontal feed shaft 23, and the shuttle shaft 11, and the output portion 53b is Since the feed shaft 22, the horizontal feed shaft 23, and the shuttle shaft 11 are extended upward, a configuration (thread trimming solenoid 56 and clutch member 55) for operating the knife drive arm 53 is arranged in the lower area. In the upper area, a configuration (first and second link bodies 58 and 61, a knife position adjusting body 59, etc.) for transmitting an operation from the knife driving arm 53 to the thread trimmer 30 can be arranged.
And since the knife drive arm 53 that rotates around the support shaft 54 parallel to the vertical feed shaft 22 extends from the lower area to the upper area, while maintaining the upright state as in the prior art, Since the transmission body (see reference numeral 115 in FIG. 6) for transmitting the horizontal movement from the female drive arm to the link body is unnecessary, the swinging movement direction of the female drive arm 53 can be matched with the movement transmission direction. It is possible to suppress transmission delay and transmission failure due to falling, and it is possible to improve the stability of the cutting operation.

  Further, the sewing machine 10 has a structure in which the knife driving arm 53 moves back and forth along the support shaft 54 and rotates around the support shaft 54, but operates from the knife driving arm 53 to the thread trimming device 30 side. Since the first link body 58 that performs transmission is provided with spherical bearings 58a and 58b at both ends, even if displacement in the X, Y, and Z-axis directions occurs at the rotating end of the knife drive arm 53, this is possible. Therefore, it is possible to appropriately transmit the motion to the first rotating piece 64 of the female position adjusting body 59 in a flexible manner corresponding to the displacement generated in each direction, and to perform the cutting operation smoothly and stably. Become. In addition, since the two spherical bearings 58a and 58b suppress the occurrence of sliding that increases the load only in some directions in the motion transmission, the deterioration of each component due to wear and the like is suppressed, and the entire mechanism is maintained. And durability can be improved.

Further, since the sewing machine 10 is provided with the second stopper 60 and the tension spring 68 and the initial position of the roller 52 can be adjusted freely, the roller 52 smoothly moves into the cam groove 51a when the knife drive arm 53 moves forward and backward. It becomes possible to adjust so that it may fit, and it becomes possible to improve the operativity of thread trimming.
In the sewing machine 10, the second stopper 60 contacts the knife position adjusting body 59 to position the roller 52, but the moving knife driving arm 53, including the moving knife driving arm 53, performs the thread trimming device 30. The position of the roller 52 may be adjusted by bringing the second stopper 60 into contact with any member that transmits the operation up to the above.

  In the sewing machine 10, the knife position adjusting body 59 is provided, and the initial position of the moving knife 31 can be adjusted by adjusting the angle of the first rotating piece 64 and the second rotating piece 65. Even when this position adjustment is performed, the initial position of the moving knife 31 can be adjusted to an appropriate position independently of this, and a stable thread trimming operation without defects can be performed.

2a Sewing bed upper surface 10 Sewing machine 11 Hook shaft 20 Cloth feed device 21 Feed base 22 Vertical feed shaft 23 Horizontal feed shaft 30 Thread trimmer 31 Moving knife 50 Thread trimmer drive mechanism 51 Thread trimmer cam 51a Cam groove 52 Roller (cam follower) )
53 Female drive arm 54 Support shaft 56 Thread trimmer solenoid (actuator)
58 First link body (link body)
58a, 58b Spherical bearing 59 Female position adjustment body (Female position adjustment means)
60 Second stopper (stopper)
61 Second link body (moving knife drive link)
64 1st rotation piece (1st L-shaped rotation link)
65 Second rotating piece (second L-shaped rotating link)
66 Connection screw 67 Step screw (support shaft)
68 Tension spring (spring)

Claims (6)

A thread trimmer provided with a moving knife for cutting a sewing thread by reciprocating rotation;
A thread trimming drive mechanism that applies a cutting operation to the moving knife of the thread trimming device using a sewing motor;
A cloth feed mechanism comprising a feed dog, a vertical feed shaft that rotates once in the same cycle as the upper shaft and imparts vertical motion to the feed dog, and a horizontal feed shaft that imparts longitudinal motion to the feed dog,
The thread trimming drive mechanism is
A thread trimming cam that is rotationally driven by a sewing machine motor;
A knife drive arm that imparts a cutting action to the moving knife by performing a pivoting action;
A cam follower which is provided on the knife driving arm and applies a turning motion to the knife driving arm by fitting into a cam groove of the thread trimming cam;
In a sewing machine comprising: an actuator that applies a position switching operation of the female drive arm to a fitting position where the cam follower is fitted into a cam groove of the thread trimmer cam and a retracted position where the cam follower is not fitted;
It is supported by a sewing machine frame so as to be movable along the vertical feed shaft direction, and includes a support shaft that rotatably supports the knife driving arm,
The thread trimming cam is provided on the vertical feed shaft, and the cam groove is formed on an end surface perpendicular to the vertical feed shaft with a direction along the vertical feed shaft direction as a depth direction.
The sewing machine is characterized in that the female drive arm is capable of switching the cam follower body between the fitting position and the retracted position by moving forward and backward along the vertical feed axis direction. The support shaft is disposed below the vertical feed shaft,
2. The sewing machine according to claim 1, wherein the rotary end of the knife driving arm extends from the support shaft to above the vertical feed shaft. The thread trimming drive mechanism includes a link body that transmits an operation from the knife driving arm to the thread trimming device,
The sewing machine according to claim 1 or 2, wherein the link body has spherical bearings at both ends thereof. The link body is arranged between the shuttle shaft and the upper surface of the sewing machine bed so as to intersect the shuttle shaft,
The link body has one end connected to the female drive arm and the other end connected to an L-shaped rotation link,
The moving knife drive link which is arrange | positioned so that it may cross | intersect the said link body, one end side is connected with the said L-shaped rotation link, and the other end side is connected with the said moving knife. sewing machine. A stopper that can move forward and backward with respect to the sewing machine frame and that can contact the link body or the L-shaped rotation link;
The sewing machine according to claim 4, further comprising a spring that biases the link body or the L-shaped rotation link so as to abut against the stopper. The L-shaped rotation link is configured to include two L-shaped rotation links that are rotatably supported by a support shaft and are arranged so as to partially overlap each other.
One L-shaped rotation link is connected to the link body and the other L-shaped rotation link is connected to the moving knife drive link.
6. The sewing machine according to claim 4, further comprising a connection screw for adjusting a position of the moving knife by adjusting a connection position of the two L-shaped rotation links.

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