JPH0670Y2 - Sewing machine thread tension device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a thread tension device for a sewing machine, and is particularly suitable for use as a concealed type dial tension device provided inside a sewing machine frame so as not to be exposed to the outside. The present invention relates to a thread tension device.

2. Description of the Related Art Conventional thread tension devices for sewing machines include a normal type that is exposed outside the sewing machine and a conshield type that is provided inside the sewing machine and allows thread to pass through a slit formed in the frame. In any case, the conventional thread tension device generally has a fixed tray and a pair of tension trays composed of a movable tray slidably attached to a shaft protruding from the tray.
The coil spring is wound around the shaft to elastically contact the movable plate with the fixed plate, a spring retainer slidably attached to the shaft, and an operating member for sliding the spring retainer along the shaft.

In addition, as disclosed in Japanese Patent Laid-Open No. 58-121986, the thread tension device includes a base plate having a dish receiving portion, an elastic plate having a dish-shaped surface portion, a dish receiving portion and a dish-shaped surface portion. It is known that there is a thread tension disc interposed therebetween and an adjusting knob for adjusting the thread pressing force by changing the engaging position with the elastic plate.

Problems to be Solved by the Invention According to the above-described device, the elastic plate can also have the functions of the coil spring and the spring retainer, and there is an advantage that the structure can be simplified by that amount. Corresponding to a protruding two-point support beam, the adjusting knob is moved to move the concentrated load by the knob to the protruding portion side between the fulcrums, that is, to the tension tray side, and the protruding portion even if the pressing force to the thread is increased. That is, the dish-shaped surface portion is warped, and the pressing pressure on the yarn is rather reduced.

An object of the present invention is to simplify the structure of the thread tension device and to surely adjust the pressing pressure on the thread.

According to the present invention, the thread tensioning device can be pivoted around a fixed axis by a member, a movable body slidably attached to a shaft projecting from the member, and sandwiching the thread in cooperation with the member, and an intermediate portion. A bell crank-shaped leaf spring body having one end engaged with a movable body, and an operating mechanism for engaging the other side portion of the leaf spring body to pivot the leaf spring body. It is characterized in that one leaf spring body is made to have a conventional coil spring and spring holding function.

Example FIG. 1 shows a concealed type thread tension device, in which a fixing plate 1 is provided along a slit (not shown) formed in the frame in a frame (not shown), and a shaft protruding from the fixing plate 1 is provided. The movable plate 3 is slidably attached to the
The rotation is stopped by the pin 4. The fixed plate 1 also has a shaft 5
Is orthogonal to the shaft 2 and is provided at an appropriate distance from the fixed plate, and a bell crank-shaped plate spring body 6 is rotatably supported on the shaft 5 at an intermediate portion thereof. A bending portion 6a formed in a V shape at one end of 6 engages with the movable plate 3, while the other side of the leaf spring body is engaged with an operating mechanism generally designated by A, which causes the plate to move. The bending portion 6a of the spring body 6 is pressed against the movable plate 3 so that the movable plate 3 elastically contacts the fixed plate 1.

In the illustrated embodiment, the operating mechanism A includes a pair of long holes 7
A slide plate in which a bending portion 9a, which is slidably supported in a direction orthogonal to the fixed plate 1 by pins 8 respectively fitted therein, and bent at one end to be bent into a hook shape, is engaged with the other side portion of the leaf spring body 6. 9 and a dial 11 which is rotatably attached to one of a pair of pins 8 and has an eccentric arc groove 10 into which a pin 12 protruding from a slide plate 9 is fitted. By turning 11, the slide plate 9 slides up and down to pivot the plate spring body 6, and the fixed plate 1 of the movable plate 3 is rotated.
The presser foot pressure against can be adjusted.

As the operating mechanism, various known mechanisms other than those shown in the above embodiment, for example, an eccentric cam provided coaxially with the dial is engaged with the leaf spring body, and the leaf spring body is pivoted by the rotation of the eccentric cam. Any such mechanism can be used.

In the above embodiment, the device is of the concealed type which is housed in the sewing machine, but it is also possible to expose a part or most of it to the outside of the sewing machine.

Effect of the Invention As described above, in the thread tension device of the present invention, since the leaf spring body has the functions of the coil spring and the spring retainer in the conventional thread tension device, the number of parts is reduced accordingly, and the thread tension device is reduced accordingly. The structure of the device is simplified. Further, since the leaf spring body is adapted to press a movable body which is separate from this, it is possible to surely increase or decrease the pressing force on the yarn by increasing or decreasing the pressing force on the movable body.

[Brief description of drawings]

FIG. 1 shows a thread tension device according to the present invention. FIG. 1 is a perspective view thereof, FIG. 2 is a side view thereof, and FIG. 3 is a partial sectional front view thereof. 1 ... Fixed plate 2 ... Shaft 3 ... Movable plate 5 ... Shaft 6 ... Leaf spring body 8 ... Pin 9 ... Slide plate 10 ... Arc groove 11 ... Dial

Claims (1)

[Scope of utility model registration request] 1. A member 1 and a movable body 3 which is slidably attached to a shaft 2 protruding from the member and which cooperates with the member 1 to sandwich a thread, and an intermediate portion pivoted around a fixed axis. Pivoting as possible,
A thread tension device for a sewing machine including a bell crank-shaped leaf spring body 6 whose one end engages with a movable body, and an operating mechanism A which engages with the other side portion of the leaf spring body to pivot the leaf spring body.