JPH0719431Y2 - Sewing machine thread guide device - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) This invention relates to an upper thread path from an upper thread supply source to a needle eye hole,
The present invention relates to a sewing machine provided with a thread tension device that applies thread tension pressure to the upper thread on the upper thread path, and a balance that performs an upper thread picking action between the thread tension device and the needle, and particularly, the thread. Regarding guidance device.

(Prior Art) Conventionally, in a sewing machine such as a bar tacking sewing machine, a main thread tension adjuster and a balance are arranged on a needle thread path from an upper thread supply source to a needle eye hole, and a main thread tension A sub thread tension device is arranged on the needle thread supply source side of the needle thread device, and at the time of normal stitch formation, the needle thread is fed to the needle side based on the thread tension pressure set by the main thread tension device. The amount of the upper yarn fed out during the yarn cutting operation, that is, the amount of the upper yarn remaining, is adjusted by the auxiliary yarn tensioner.

(Problems to be solved by the invention) Therefore, when the upper thread remaining amount is set to be long by the auxiliary thread tension device, when the stitches of the first stitch are formed after the thread cutting operation, the stitches formed after the thread end are formed. If it becomes impossible to sew, it will pop out of the work cloth for an unnecessarily long time, resulting in a decrease in product value, or if the upper thread remaining amount is set to a short length, during thread cutting operation or when forming the first stitch of the stitch after thread cutting operation. There is a risk that the thread end will fall out of the eye hole of the needle. Also, since the appropriate amount of remaining upper thread varies depending on the type of upper thread and the work cloth (friction resistance between the upper thread and the work cloth), the thread tension pressure of the auxiliary thread tension device is changed every time the combination is changed. However, there is a problem that skill is required.

(Object of the Invention) The present invention was made in order to solve the above problems, and its purpose is to make adjustments related to the type of work cloth and the upper thread very easy, and An object of the present invention is to provide a yarn guide device capable of preventing the end from protruding from the work cloth or coming out from the eye hole of the needle.

(Means for Solving the Problem) In order to achieve the above object, in the present invention, an upper thread path from an upper thread supply source to a thread eye hole and a thread tension on the upper thread on the upper thread path. A thread tensioner that applies pressure, a balance that performs a needle thread pick-up action between the thread tensioner and the needle, and an upper thread on the needle side of the thread tensioner that is between the thread balance and the thread tensioner. A sewing machine having a thread take-up spring arranged on the path, the thread take-up portion engaging with a needle thread on the needle thread path, and the needle thread path between the thread take-up spring and the needle during operation of the sewing machine. To bend the needle thread to lengthen the needle thread path, and to maintain the needle thread amount at a predetermined position between the first position and the upper thread path by increasing the bending angle of the needle thread path during the cutting operation of the needle thread. A thread guide piece that is rotatable between a second position that shortens and reduces the upper thread amount, and a thread guide piece that moves between the first position and the second position. And the adjusting means for adjusting the bending angle of the upper thread path, the adjusting means being formed on the thread guide piece and extending through a line segment passing through the rotation center of the thread guide piece. A first guide portion extending along the first guide portion and a second guide portion that intersects the first guide portion at a predetermined angle.
The guide portion and the engaging portion that engages with the first guide portion and the second guide portion, and an operation member that can advance and retreat along the line segment, and the first guide based on the advance and retreat of the operation member. The thread guide piece is arranged at the first position when the engaging section is engaged with the section, and the thread guide piece is arranged at the second position when the engaging section is engaged with the second guide section. In addition, the amount of rotation of the thread guide piece is adjusted according to the position of the engaging portion on the second guide portion based on the amount of advance / retreat of the operation member, and the bending angle of the needle thread path is adjusted. .

(Operation) Therefore, during the cutting operation of the needle thread, the engaging portion is engaged with the second guide portion of the thread guide piece by the forward / backward movement of the operating member, and the thread guide piece is switched to the second position. In the second position, the bending angle of the needle thread path between the thread take-up spring and the needle is increased, the needle thread path is shortened, and the needle thread amount in the meantime is reduced. Then, the reduced amount of the upper thread is sufficiently drawn out from the eye hole of the needle in association with the thread cutting operation. Further, during operation of the sewing machine, the engaging portion is engaged with the first guide portion of the yarn guide piece by advancing and retracting the operating member, and the yarn guide piece is switched to the first position. At the first position, the bending angle of the upper thread path is reduced, the upper thread path is lengthened, and the upper thread amount in the meantime is increased. Then, the needle thread pulled out from the eye hole of the needle during the thread cutting operation is appropriately pulled back at the first needle. Further, the bending angle of the upper thread path bent by the thread guiding pieces at the first position and the second position can be adjusted only by adjusting the advance / retreat amount of the operating member, and the bending angle of the upper thread and the work cloth can be changed. Accordingly, the amount of needle thread is easily adjusted.

(Embodiment) An embodiment of a bar tacking sewing cycle sewing machine embodying the present invention will be described in detail below with reference to the drawings.

As shown in FIGS. 1 and 3, a transmission 3 is attached to an end portion of a sewing machine main shaft 2 arranged in a sewing machine frame 1. That is, the transmission 3 is mounted on the sewing machine main shaft 2 so as to be slidable along the sewing machine main shaft 2 between the pair of clutch plates 4 and 5 fixed at predetermined intervals and between the two clutch plates 4 and 5, A sliding cylinder 6 biased to the right in FIG. 1,
A low speed pulley 7 and a high speed pulley 8 rotatably mounted on the sliding cylinder 6 are provided. A fixed position stop cam 9 is formed on one clutch plate 4, and a spherical body 10 is formed on the sliding cylinder 6.
Is supported.

A control lever 11 is rotatably supported by a support shaft 12 on the sewing machine frame 1, and a cam surface 13 formed on the upper end of the control lever 11 is engaged with the spherical body 10. When the control lever 11 is rotated counterclockwise from the standby position shown in FIG. 3, the locking projection 14 on the control lever 11 is disengaged from the recess 9a of the fixed position stop cam 9. The rotation of the sewing machine main shaft 2 is allowed, and the sliding cylinder 6 and the pulleys 7 and 8 are slid back and forth integrally through the engagement of the cam surface 13 and the spherical body 10, so that the pulleys 7 and 8 When the side faces are sequentially joined to the clutch plates 4 and 5, and the low speed pulley 7 is joined to one clutch plate 4, the sewing machine main shaft 2 is passed through the belt 7a of the low speed pulley 7.
Is connected to the low speed drive source, and when the high speed pulley 8 is joined to the other clutch plate 5, the sewing machine main shaft 2 is connected to the high speed drive source via the belt 8a on the high speed pulley 8.

An operating lever 15 is rotatably supported by a supporting shaft 16 on the sewing machine frame 1 and is always arranged at a rest position shown in FIG. An intermediate operating lever 19 is rotatably supported on the support shaft 16, and a connecting rod 20 is rotatably connected between the intermediate operating lever 19 and the control lever 11 by a pair of upper and lower connecting pins 21 and 22. Has been done. Then, a part of the intermediate operating lever 19 is engaged with the stopper 23 by the urging force of a spring (not shown) acting on the intermediate operating lever 19, so that the control lever 11 is brought to the standby position in FIG. Retained. Further, the operation lever 15 is formed with a long hole 24 located on an arc centered on the support shaft 16, and the connecting pin 22 is loosely fitted in the long hole 24.

On the other hand, the sewing machine frame 1 has a needle bar 31 having a needle 30 at the lower end.
Is vertically movably supported, and a balance 32 is vertically movably supported on the needle thread supply source (not shown) side of the needle bar 31.
Both 31 and 32 are operated in synchronization with the rotation of the sewing machine main shaft 2. As shown in FIGS. 1 and 4, on the upper thread path P from the upper thread supply source (not shown) to the eye hole 30a of the needle 30, a main thread take-up spring 33a is provided in front of the sewing machine frame 1. The thread tension regulator 33 and the auxiliary thread tension regulator 34 are arranged vertically at a predetermined interval. Each thread tension device 33, 34 applies a thread tension pressure to the thread rod 35 projecting from the sewing machine frame 1, a pair of thread tension discs 36 inserted into the screw rod 35, and the thread tension disc 36. A spring 37 and an adjusting knob 38 screwed to the screw rod 35 for adjusting the thread tension pressure of the spring 37 are provided. Further, the operating rod 39 and the spring receiving tray 37a are slidably inserted into the screw rod 35 of the main thread tension regulator 33, and the tip of the operating rod 39 is engaged with and disengaged from the spring receiving tray 37a.

As shown in FIGS. 1, 2, and 6, a rod 40 is movably supported in the sewing machine frame 1, and one end of the rod 40 has two holding surfaces having different distances from the axial center of the rod 40. 41
A pressure switching portion 41 is formed by a and 41b and a cam surface 41c that connects the holding surfaces 41a and 41b. Then, when the first holding surface 41a is engaged with the operating rod 39 as the rod 40 moves, the operating rod 39 is arranged in the outward movement position, and the spring is moved.
Against the urging force of 37, the spring tray 37a is located on the outside
And the thread tension pressure for the upper thread Y is released. Also, when the second holding surface 41b is arranged to face the actuation rod,
Based on the urging force of the spring 37, the operating rod 39 is arranged at the inward moving position, and the outer thread tension disc 36 is brought into close contact with the inner thread tension disc 36 via the spring tray 37a to thread the upper thread Y. Toning pressure is applied. Unlike the main thread tension device 33, the auxiliary thread tension device 34 in this embodiment always applies a required thread tension pressure to the upper thread Y.

As shown in FIGS. 1 and 3, between the other end of the rod 40 and the upper end of the connecting rod 20, the sewing machine frame 1 has an L
A character-shaped intermediate lever 42 is rotatably supported at its intermediate portion, and one end thereof is connected to the rod 40. on the other hand,
A connecting pin 43 is mounted on the upper end of the connecting rod 20 so that the vertical position can be adjusted, and the connecting pin 43 is engaged with a fork portion 44 formed at the other end of the intermediate lever 42. And the continuous rod
When 20 is moved up and down, the rod 40 is reciprocated in the left-right direction in FIG. 1 through the rotation of the intermediate lever 42.

As shown in FIGS. 1 and 2, a thread guide piece 50 is rotatably supported by a support pin 51 at its central portion in the vicinity of the main thread tension device 33, and a main portion is provided on one side thereof. An arcuate winding portion 52 located below the thread tension regulator 33 is formed, and an inverted U-shaped thread hooking portion 53 is bent at the tip of the winding wire portion 52, and the thread hooking portion 53 is formed. Is arranged on the upper thread path Pa between the main thread tension unit 33 and the balance 32. And the thread guide piece 50
As shown by the chain double-dashed line in FIG. 1, the thread hooking portion 53 is positioned at the top dead center of the thread hooking portion 53.
In order to minimize the bending angle θ (see FIG. 2) of the upper thread path Pa formed by the main thread tension regulator 33, the upper thread path Pa is bent at the most acute angle to lengthen the upper thread path Pa. By doing so, the first position for holding the upper thread amount Ya between them at a predetermined amount (maximum) and the upper thread path as shown by the solid line in the drawing.
By increasing the bending angle θ of Pa and shortening the needle thread path Pa, it is moved between a second position where the needle thread amount Ya during that time is reduced to the minimum.

On the other side of the yarn guide piece 50, there is a length consisting of a first guide portion 54a extending along a line segment passing through the center of rotation and a second guide portion 54b intersecting the first guide portion 54a at a predetermined angle. A hole 54 is formed. Also, as shown in FIGS. 2 and 5, a cylindrical body 56 is inserted near the front end of the rod 40 so that the position of the cylindrical body 56 can be adjusted along the rod 40, and the elongated hole of the sewing machine frame 1 is inserted into the cylindrical body 56. A positioning screw 57 exposed through the circular opening 1a is screwed, and an operating pin 55 that penetrates the opening 1a and engages with the elongated hole 54 is screwed.

Then, as shown in FIG.
With the tubular body 56 fixed at an arbitrary adjustment position on the rod 40, the operation pin 55 is engaged with the second guide portion 54b of the elongated hole 54, so that the thread guide piece 50 is moved to the position shown in FIG. Second shown by solid line
When the operation pin 55 is engaged with the first guide portion 54a, the yarn guide piece 50 is arranged at the first position shown by the chain double-dashed line in FIG. Further, by loosening the positioning screw 57 and adjusting the arrangement position of the tubular body 56, the thread guide piece is engaged with the operating pin 55 on the tubular body 56 and the elongated hole 54 of the thread guide piece 50. The second position of 50 is fine-tuned.

Next, the operation of the thread guide device in the cycle sewing machine configured as described above will be described. 1, 3 and 4
In the figure, the upper thread Y is on the upper thread path P, the auxiliary thread tension device 34, and the main thread tension device 3
3, the needle 30 via the thread hooking portion 53 of the thread guide piece 50 and the balance 32, etc.
It shows a state in which the sewing machine is stopped in a state where the sewing machine is inserted into the eye hole 30a.

In this state, when the operating lever 15 is operated to lower the connecting rod 20 through the engagement between the elongated hole 24 and the connecting pin 22,
The intermediate lever 42 is rotated in the clockwise direction in FIG. 1 through the engagement of the connecting pin 43 and the forked portion 44, and the rod 40 is accordingly rotated.
Is moved to the right in FIG. Then, along the cam surface 41c of the pressure switching portion 41 of the rod 40, the actuating rod 39 of the main thread tension regulator 33 is moved inward by the spring 37, as shown in FIG. The thread tension disc 36 is brought into close contact with the inner thread tension disc 36, and the upper thread Y is sandwiched between the two thread tension discs 36. After this upper thread clamping operation, the rod 40
Movement of the rod 40 causes the operating pin 55 on the rod 40 to
Is disengaged from the second guide portion 54b and is engaged with the first guide portion 54a,
Based on this, the yarn guide piece 50 is moved from the second position shown by the solid line in FIG. 1 to the first position shown by the two-dot chain line in FIG. The movement of the thread guide piece 50 lengthens the upper thread path Pa and increases the upper thread amount Ya during that time. Therefore, as described later, the needle is cut by the thread cutting operation prior to the sewing machine starting operation.
The amount Yb of the upper thread that has been sufficiently drawn in advance from the eyelet 30a of 30
Is reduced.

Further, as the connecting rod 20 moves downward, the transmission 3 is operated via the control lever 11, and the transmission 3 connects the sewing machine main shaft 2 to each drive source in order of low speed, high speed, and low speed. , The sewing machine main shaft 2 is rotated according to the connection state with each drive source. When the sewing machine main shaft 2 starts rotating, that is, when the first stitch is formed, the needle thread remaining amount Yb of the needle tip is smaller than that immediately after the thread cutting operation, as described above. It is possible to prevent the yarn end from jumping out of the work cloth longer than necessary. Further, during the low speed and high speed operation of the sewing machine, the thread guide piece 50 is held at the first position, and a predetermined amount of needle thread Y is applied to the needle 30 at each stitch formation via the thread guide piece 50 and the like. Supplied.

When the control lever 11 shown in FIG. 3 is returned to the standby position shown in FIG. 3 and rotated after the stitches for a predetermined number of stitches have been formed, the transmission 3 is operated by the feed control mechanism (not shown). The connection between the sewing machine spindle 2 and the low-speed drive source is cut off, and the control lever
When the locking projection 14 of 11 is engaged with the concave portion 9a of the fixed position stop cam 9, and the balance 32 reaches the top dead center, the sewing machine spindle 2 is stopped.

Further, the connecting rod 20 is moved upward with the return rotation of the control lever 11, and based on this, the rod 40 is moved via the intermediate lever 42.
Is moved to the left in FIG. As a result, the second holding surface 41b of the pressure switching portion 41 of the rod 40 is separated from the actuating rod 39, and the actuating rod 39 is moved outward along the cam surface 41c, and then outward by the first holding surface 41a. Held in the moving position,
As a result, the spring tray 37a is separated from the outer thread tension disc 36 and the upper thread Y is released. Further, as the rod 40 moves, the operating pin 55 on the rod 40 separates from the first guide portion 54a of the elongated hole 54 and engages with the second guide portion 54b. The needle thread path Pa is shortened by moving from the first position to the second position.

Therefore, after the rotation of the sewing machine main shaft 2 is stopped, when the thread cutting operation by the known thread cutting mechanism including the fixed blade and the movable blade is performed, the movable blade causes the needle thread Y to be formed more than in the normal stitch formation. As the upper thread path Pa is shortened, the upper thread amount is reliably delivered more, and the upper thread amount Ya decreases. Therefore, it is possible to sufficiently secure the needle thread remaining amount Yb at the needle tip at the time of thread cutting to prevent the thread end from coming off from the eye hole 30a of the needle 30 by the thread cutting operation, and at the same time of the next sewing operation. 30 holes for 1st stitch
It is possible to secure a sufficient amount Yb of the upper thread remaining so that the thread end does not come off from a.

Further, in this embodiment, the arrangement position of the operating pin 55 is set to the rod.
Can be adjusted along the 40, thereby enabling the actuation pin
The relative positional relationship between 55 and the long hole 54 is changed, and the bending angle θ of the needle thread path Pa when the thread guide piece 50 is arranged at the second position is changed. Therefore, the amount of movement of the thread guide piece 50 between the second position and the first position can be finely adjusted to easily and reliably adjust the amount of the upper thread fed during the thread cutting operation. According to the combination of the cloth and the upper thread Y, the upper thread remaining amount Yb of the needle tip after the thread cutting operation and the upper thread feeding amount during the sewing machine operation can be easily correlated with each other.

The invention is not limited to the above embodiment,
For example, the rod 40 can be moved back and forth by a driving means such as an electromagnetic solenoid, or can be embodied in various sewing machines other than the cycle sewing machine.

(Effects of the device) As described in detail above, this device is very easy to make adjustments related to the type of the upper thread, and the thread end of the upper thread jumps out of the work cloth or comes out of the eye hole of the needle. It has an excellent effect that it can be prevented.

[Brief description of drawings]

FIG. 1 is a side view showing a main portion of a bar tacking sewing cycle sewing machine embodying the present invention, FIG. 2 is a partially enlarged side view showing a mounting state of an operating pin and a needle thread path, and FIG. 3 is a cycle sewing machine. 4 is a partially enlarged front view, FIG. 5 is a partially enlarged front sectional view, and FIG. 6 is a partially enlarged plan view. 30: needle, 32: balance, 33: main thread tensioner, 33a: thread take-up spring, 40: rod as an operation member constituting the adjusting means, 50: thread guide piece, 53: thread hook Department, 54a, 54b ...
... first and second guide portions constituting adjusting means 55, operating pin as an engaging portion constituting adjusting means, Pa ... needle thread path, Y ... needle thread, .theta .... bending angle, 30a …… Eye, Ya…
… Amount of needle thread.

Claims (1)

[Scope of utility model registration request] 1. A needle thread path (P) extending from an upper thread supply source to an eyelet (30a) of a thread (30) and a thread tension pressure applied to the upper thread (Y) on the upper thread path (P). A thread tensioner (33) to be applied, a thread balance (32) for picking up the upper thread between the thread tensioner (33) and the needle (30), the thread balance (32) and the thread tensioner (33). )
And a thread take-up spring (33a) arranged on the needle thread path (P) closer to the needle (30) than the thread tension regulator (33). Thread hooking part (5
3), the upper thread path (Pa) between the thread take-up spring (33a) and the needle (30) is bent during operation of the sewing machine to lengthen the upper thread path (Pa) and The first position for holding the yarn amount (Ya) at a predetermined amount, and the bending angle (θ) of the upper yarn path (Pa) are increased during the cutting operation of the upper thread (Y) to increase the upper thread route (Pa). A yarn guide piece (50) which is rotatable between a second position where the yarn guide piece (50) is shortened and which reduces the upper thread amount (Ya), and the yarn guide piece (50) is at the first position and the second position. The needle thread path (Pa) bending angle (θ)
And adjusting means (40, 54a, 54b, 55) for adjusting the yarn, which is formed on the thread guide piece (50) along a line segment passing through the rotation center of the thread guide piece (50). The first guide portion (54a) extending in the longitudinal direction, the second guide portion (54b) intersecting the first guide portion (54a) at a predetermined angle, and the first guide portion (54a) and the second guide portion (54b). The operating member (40) is provided with an engaging portion (55) to be engaged with and can move back and forth along the line segment, and is engaged with the first guide portion (54a) based on the moving back and forth of the operating member (40). When the joint portion (55) is engaged, the thread guide piece (50) is arranged at the first position, and the second guide portion (54
When the engagement portion (55) is engaged with b), the thread guide piece (50) is arranged at the second position, and the engagement portion (55) is moved to the first position based on the amount of advance / retreat of the operation member (40). 2 Thread of a sewing machine, characterized in that the bending amount (θ) of the needle thread path (Pa) is adjusted by adjusting the amount of rotation of the thread guide piece (50) according to the position on the guide portion (54b). Guidance device.