JPH0866Y2 - Structure of automatic thread tensioner in sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a needle thread control technique in a sewing machine, and in particular, the needle thread is clamped between two rollers while the rollers are rotationally controlled to control the needle thread. The present invention relates to a structure of an automatic thread tensioner in a sewing machine, which can prevent the thread from coming off at a thread delivery section of a sewing machine that controls the delivery amount.

[Conventional technology]

Conventionally, an automatic thread tensioner having a structure shown in FIG. 5 has been used as an automatic thread tensioner for a sewing machine that automatically controls the amount of the upper thread fed out according to a set value. This type of automatic thread tensioner 51 is configured in a yarn path between a thread top mounted on a sewing machine (not shown) and a thread take-up, and is rotationally driven by a main shaft via a rotary drive transmission means that is interlocked with a main shaft rotated by a drive source (not shown). The pressing roller 17 is detachable and contactable in the direction of arrow A with respect to the cylindrical feeding roller 13 by operating an operation lever pivotally supported by a sewing machine arm (not shown). Since the yarn is fed by the rotation angle of the feeding roller 13 while being held between 17, it is possible to secure a desired supply amount of the upper thread a by controlling the rotation drive transmission means or the like for transmitting the rotation to the feeding roller 13.

[Problems to be solved by the device]

However, in the structure of the above-mentioned automatic thread tensioner 51, the upper thread a is vertically moved up and down and back and forth due to structural factors such as the inclination of the feeding roller 13, the shape of the feeding roller 13 and the yarn path, etc. The upper thread a comes off from between and the upper thread a
The control supply of may become impossible. Further, by rotating the operation lever up or down, the pressing roller 17 is retracted and separated from the feeding roller 13 (the pressing roller 17 moves to the right in FIG. 5 (a)). There is a problem that "slip (thread plays in the vertical direction of the roller)" or the like is caused due to a bending tendency and the like, and the thread comes off the delivery roller 13.

The present invention has been made in view of the above problems, and in an automatic thread tensioner that controls the supply amount while holding the upper thread between the feeding roller and the pressing roller that are rotationally driven by the rotational driving transmission means, An object of the present invention is to provide a structure of an automatic thread tensioner in a sewing machine in which a thread does not come off from a roller and a thread can be easily hooked.

[Means for solving the problem]

The structure of the automatic thread tension device in the sewing machine according to the present invention is as follows.
A feeding roller (13) that is rotatably supported while being linked to the main shaft of the sewing machine, a pressing roller (17) that can come into contact with and separate from the feeding roller, and a drive control means (40) that controls the rotation of the feeding roller. ), And an automatic thread tensioner of a sewing machine that clamps the thread from the thread supply source between the rollers to control the thread supply amount, and is supported by the pressing roller and An undercut thread disengagement prevention means (24) for guiding the thread to a predetermined range in the axial direction of the roller, and a threading mistake prevention mechanism (45) capable of opening and closing the thread path from the rollers to the needle.
And an operating lever (6) for interlocking the presser roller and the threading mistake prevention mechanism, and by rotating the operation lever, the pressing roller is brought into and out of contact with the threading mistake prevention mechanism at the same time. I did it.

[Action]

In the above automatic thread tensioner, since the upper thread is always held by the thread insertion portion of the thread detachment preventing means formed on the pressing roller support arm, when the upper thread is sandwiched between the rollers and is fed out, the thread is held on the pressing roller side. It acts so as to move closer to the roller and regulates the deviation of the yarn, so that it is prevented from falling off from between both rollers,
Stable supply of needle thread.

Further, since the pressing roller is separated by the forward rotation of the operation lever and the yarn hooking error preventing mechanism is opened at the same time to open the yarn path, the yarn hooking operation can be performed quickly.

After that, with respect to the yarns in the yarn path of both rollers from the yarn supply source, the pressing roller and the yarn disengagement prevention means come close to the payout roller by the reverse rotation of the operation lever, and the yarn disengagement prevention automatically having the undercut shape Guided by the mechanism.

〔Example〕

An embodiment of the structure of an automatic thread tensioner in a sewing machine according to the present invention will be described below with reference to the drawings.

1 to 3 are a plan view, a front view and an enlarged view of an essential part of the automatic thread tensioner 1, which is shown in FIG.
As shown in the drawing, the thread path from the thread top (not shown) attached to the sewing machine head 2 to the thread balance 3 is constituted.
The upper thread a passing through the sewing machine is supplied to the sewing machine needle 4 attached to the lower end of the needle bar, and the main shaft 5 of the sewing machine is used as a drive source and an operating lever pivotally provided on the front surface of the sewing machine head 2. The upper thread is hooked by rotating 6 (arrow B).

 FIG. 5 is a perspective view from the sewing machine head.

A yarn path 50 guides a yarn from a yarn supply source (thread winding) to a needle (not shown) by a notch provided on the sewing machine head top plate 52. At this time, by rotating the operation lever 6 which will be described later, the pressing roller 17 is separated and the yarn path closing member 47 is opened at the same time to secure the yarn path 50, and the thread detachment prevention mechanism and both rollers are provided.
Make sure to guide the thread between 13 and 17.

Reference numeral 7 is a base of the automatic thread tension device 1, and a sewing machine head 2
It is fixed to the machine frame. Reference numeral 13 denotes a feeding roller having a tooth portion 13a on its outer periphery, and the feeding roller 13 projects from a through hole of a thread tension plate 15 provided on the base 7 so as to be located below the sewing machine head 2. The pay-out roller shaft 11 penetrates the pay-out roller spring receiver 10 and the pay-out roller 13, has its upper shaft screwed with a nut 11a, and has its lower end rotatably supported on the base 7 via a driven gear 11b. To be done. The feeding roller shaft stopper plate 9 is a disk that is sandwiched between the feeding roller 13 and the feeding roller spring receiver 10, and the outer peripheral portion of the feeding roller shaft stopper plate 9 is a movable body 8a of the solenoid 8 and an upper portion 8b of the yoke. It is designed to intervene in the gap between and. The main shaft 5 shown in FIG. 4 is rotated by a plurality of bevel gears 12 axially installed on the main shaft drive gear 5a and the base 7 shown in FIG. 2 (one in each of the front face and the rear face in FIG. 2).
The feed roller shaft 11 is rotated by the rotation drive transmission means including the driven gear 11b and the feed roller 13 and the pressing roller 17 to feed the upper thread a. Further, the feeding roller shaft stopper plate 9 is sandwiched by the excitation of the solenoid 8 to forcibly stop the feeding roller 13 and the feeding roller spring receiver 10 from rotating, and the rotation of the feeding roller 13 is restricted. The delivery roller 13, the delivery roller spring receiver 10, the delivery roller shaft stopper plate 9, the solenoid 8 and the like constitute drive control means. Further, on the upper surface of the base 7, a long hole (not shown) is provided in the base end portion 21a of the sliding plate 21, and the shaft 16 standing on the press roller supporting arm 18 is pressed by the press roller.
The base end of a press roller support arm 18 which is loosely fitted to the base 17, the shaft end of which is axially mounted on the base end 21a, and the press roller 17 is pivotally mounted, is rotatably pivoted via a pin shaft 19. Then, the pressing roller 17 is displaced in the direction of the arrow C so that the pressing roller 17 can be moved into and out of contact with the feeding roller 13. Shaft 16 with the above presser roller 17
Is a projecting shaft 20, 20 projectingly provided on the upper surface of the base 7, which engages with a sliding plate 21 slidably (in the direction of arrow D) through a long hole 22, 22 in the displacement direction. The pressing roller 17 is constantly elastically urged in the direction in which it is pressed against the feeding roller 13 by the coil spring 23 that is pulled and elastically urged between the sliding plate 21 and the base 7. Further, a thread disengagement prevention means 24 is formed integrally with this member at the pivotal end of the pressing roller support arm 18, and the thread disengagement prevention means 24 has a planar shape as shown in FIG. A thread having an undercut structure 28 formed by an upper jaw portion 26 having a hook-shaped tip 25 and a lower jaw portion 27 facing the upper jaw portion 26, which is formed of a circular arc-shaped plate close to the outer periphery of the roller 17 and surrounds the front side. The insertion section 29 is configured. Further, reference numeral 30 is a connecting slide plate in which elongated holes 32, 32 are slidably (in the direction of arrow E) provided in projecting shafts 31, 31 provided on the upper surface of the base 7. Is a slide plate 21 via a relief amount adjusting member 34 which is fastened via a screw 33 so as to be adjustable in a retracted position (direction of arrow E).
It is separated from the rear end of. The rear end of the connecting slide plate 30 engages with the swing end of the lever arm 36 pivotally attached to the base 7 via the pin shaft 35 in the displacement direction, and the working end of the lever arm 36. A rocking cam 39 axially mounted on an operating shaft 38 formed by pivoting an operating lever 6 pivotally mounted on the front surface of the sewing machine head 2 with a pin 37 provided on the sewing machine head 2.
The sliding contact plate is slidably contacted, and the connecting slide plate 30 is displaced in the direction of arrow E by rotating the operation lever 6 (arrow B). Also sign
Reference numeral 40 denotes a rotary position detection plate of an encoder axially attached to the feeding roller spring receiver 10 side of the drive control means, and the rotation position detection plate 40 has radial slits formed at circumferential intervals. Photo-interrupter 42 facing both sides of the board
And a rotation angle detection means having a detection unit, and the drive output means is controlled by an electric signal from a central processing unit (CPU) (not shown) via an amplification unit 44 arranged on the printed board 43 by the detection output. Rotate roller 13 intermittently.

Reference numeral 45 is a thread hooking error preventing mechanism that is formed in association with the automatic thread tensioner 1, and is a thread path closing member in which the lower end portion is pivotally attached to the end portion of the base 7 via a shaft 46. The engaging projection 48 projecting from the lower end of 47 and the engaging projection 49 projecting from the end of the connecting slide plate 30 are rotated in the arrow F direction by the rotation of the operation lever 6 and are normally twisted. The spring 47a has a structure in which it is elastically biased in the direction opposite to the arrow F, and the bent tip of the yarn path closing member 47 crosses the upper thread drop hole 50 formed in the head portion 2 of the sewing machine and moves backward. The pressing roller 17 is displaced to the position where the pressing roller 17 is retracted and the backward opening is synchronized.
Next, the operation of the automatic thread tension device in the sewing machine according to the present invention will be described.

In the automatic thread tensioner 1 having the above structure, the upper thread a can be caught by the rotation of the operation lever 6. Operating lever 6
When is rotated, the swing cam 39 pivotally attached to the operation shaft 38 is rotated to rotate the lever arm 36, whereby the connecting slide plate 30 and the escape amount adjusting member 34 are moved in the direction E (see FIG. 1). Since it slides in the right direction and presses the slide plate 21, the slide plate 21 slides and moves to the right. As a result, the pressing roller 17 is separated and retracted from the feeding roller 13 via the sliding plate 21 and the shaft 16. At this time, the presser roller 17 is displaced along the locus of the arrow C by the presser roller supporting arm 18, and the hook-like tip of the thread detachment preventing means 24.
25 is retracted from the thread path of the upper thread a. In addition, the above connecting sliding plate 30
When is moved to the right, the yarn path closing member 47 of the yarn hooking mistake prevention mechanism 45 rotates in the direction of the arrow F and retracts from the upper thread drop hole 50 to open the yarn path.

When the upper thread a is dropped from this state, the upper thread a falls between the feeding roller 13 and the pressing roller 17 and is positioned on the thread tension plate 15. Next, when the operation lever 6 is moved to the inoperative position, each member is displaced in the opposite direction to the above, and the pressing elasticity of the coil spring 23 causes the pressing roller 17 to come into pressure contact with the feeding roller 13. At this time, the thread detachment preventing means 24 acts so that the hook-shaped tip 25 enters the thread path and slides into the thread insertion portion 29 at the tip portion, and the upper thread a passes through the thread insertion portion 29 and both rollers 13, When it is clamped between 17 and sewing is started in this state, the feeding roller 13 is rotationally driven by the main shaft 5, the rotation driving means and the drive control means, and the upper thread a is fed. Then, a predetermined rotation angle of the feeding roller shaft 11 is detected by the photo interrupter 42 based on a command from the CPU, and the drive control means, that is, the feeding roller shaft stopper plate 9 is operated by the solenoid 8 during the predetermined rotation angle. By restraining and braking the feeding roller 13, the feeding amount of the yarn can be properly controlled.

According to the structure of the thread detachment preventing means 24, when the pressing roller 17 is separated from the feeding roller 13 by the vertical rotation of the operation lever 6, the upper thread a is hooked on the undercut structure 28 of the upper jaw portion 26, and the pressing roller 17 is pressed. It acts to pull the thread close and prevent it from coming off. Further, in the above-mentioned embodiment, the rotation of the operation lever 6 causes the sliding plate 21 to linearly slide on the base 7 as shown in FIG. 1, and the shaft 16 is displaced to the base end portion 21a of the sliding plate 21. Although the pressing roller 17 is separated from the feeding roller 13 by engaging in the direction, the sliding plate 21 is curvedly slid by the rotation of the operation lever 6 and the shaft 16 is rotated in the displacement direction. Produce the effect of.

[Effect of device]

As described above, in the structure of the automatic thread tensioner in the sewing machine according to the present invention, since the upper thread is always held by the thread insertion portion of the thread detachment preventing unit which is integrally formed with the pressing roller supporting arm, the thread is not dropped. Less is. Further, when the upper yarn is sandwiched between the rollers and is fed out, the yarn detachment preventing means acts so as to bring the yarn closer to the pressing roller side, so that the deviation of the yarn is regulated to prevent the yarn from falling off. Further, since the pressing roller is separated and the yarn hooking error preventing mechanism is opened simultaneously by the rotation of the operation lever, the yarn hooking operation can be performed quickly and reliably.

Further, after the thread is hooked, the thread in the thread path from the thread supply source to the rollers is brought into contact with the feeding roller by the pressing roller and the thread detachment preventing means by the rotation of the operation lever, and the undercut shape is automatically formed. It is surely guided by the thread detachment prevention mechanism having.

[Brief description of drawings]

FIG. 1 is a plan view of an automatic thread tensioner showing an embodiment of the structure of an automatic thread tensioner in a sewing machine according to the present invention, FIG. 2 is a front view of the same, and FIG. 3 is an enlarged perspective view of thread detachment preventing means. FIG. 4 is a perspective view of the essential part of the sewing machine showing the constituent positions of the apparatus, and FIGS. 5 (a) and 5 (b) are a plan view and a front view of the essential part of a conventional automatic thread tensioner. FIG. 6 is a perspective view of the sewing machine head of the present invention. 1 ... Thread tension device, 5 ... Spindle 6 ... Operation lever, 7 ... Base 8 ... Solenoid, 13 ... Feed roller 15 ... Thread tension plate, 17 ... Press roller 18 ... Press roller support Arm, 21 ...... Sliding plate 21a ...... Base end, 23 ...... Coil spring 24 ...... Thread detachment prevention means, 25 ...... Hook-like tip 28 ...... Undercut structure, 29 ...... Thread insertion part 30 ...... Connection sliding plate, 34 …… Escape amount adjusting member 36 …… Lever arm, 38 …… Operating shaft 39 …… Rotating cam, 40 …… Rotation position detection panel 42 …… Photointerrupter 45 …… Threading mistake prevention mechanism 47 …… Thread path closing member, 50 …… Upper thread drop hole

Claims (1)

[Scope of utility model registration request] 1. A feeding roller (13) which is rotatably supported while being interlocked with a main shaft of a sewing machine, a pressing roller (17) which can come into contact with and separate from the feeding roller, and controls the rotation of the feeding roller. Drive control means (4
0), and an automatic thread tensioner of a sewing machine that sandwiches a thread from a thread supply source between the rollers to control the thread supply amount, and is supported by the pressing roller and at the thread supply source side. An undercut yarn disengagement preventing means (24) for guiding the yarn of the above-mentioned yarn to a predetermined range in the axial direction of the roller, and a yarn hooking mistake preventing mechanism (45) capable of opening and closing the yarn path from the both rollers to the needle. An operating lever (6) for interlocking the presser roller and the threading error preventing mechanism, wherein the pressing roller is brought into and out of contact with the threading error preventing mechanism at the same time by rotating the operation lever. The automatic thread tension mechanism of the sewing machine.