JPH0510785Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a thread tension device for an overlock sewing machine equipped with a thread loosening mechanism.

Conventional technology As is well known, the overlock sewing machine
Through the cooperative work of the needle and looper, a seam is usually formed by the needle thread and multiple looper threads, and tension is applied to the thread along the thread path from the spool to the needle or looper. However, conventional devices of this type are independent from each other and can be individually attached to the sewing machine body.

Problems to be Solved by the Invention and Means for Solving the Problems The present applicant first developed a single thread tension device in order to lower manufacturing costs by unitizing multiple thread tension devices, and to reduce assembly costs by halving the labor during assembly. We proposed a device with multiple thread tension devices installed on a fixed shaft. This invention further provides the above device with a thread loosening mechanism that utilizes a fixed shaft.

a pair of tone plates, and a spring means that engages with one of the pair of tone plates and presses the plate against the other plate; an adjusting means for adjusting the spring force of the spring means; and an adjusting means which is operated by rotation of the operating shaft and moves one of the above-mentioned tone plates or spring receivers in the axial direction of the operating shaft against the action of the spring means; A plurality of sets of thread tension devices each consisting of thread loosening means for releasing presser foot pressure are installed at appropriate intervals, manual operating members are connected, and the operating shafts are rotated by operating the manual operating members. The thread loosening means is activated,
The thread loosening of each thread tension device is performed at the same time.

Here, the operating shaft is supported directly on the sewing machine body or on a mounting member attached to the sewing machine body.

The spring means is a coil spring fitted to the operating shaft, or a plate spring of the type previously proposed by the applicant in Utility Application No. 1983-9016, which is supported by the mounting member so as to be pivotable about a fixed axis, and is free to rotate. An example is a leaf spring whose end is engaged with a tension plate. When using the former type of coil spring, the spring may act directly on the tension plate, but it is preferable to use a spring receiver. It is made to act on the tone plate through.

In the type of adjustment means that uses a coil spring, there is a spring holder that is screwed onto the shaft, and the spring holder is slidable in the axial direction and integrally connected in the rotational direction, and can only be rotated around the shaft. A mechanism consisting of a dial that is pivotally supported on the shaft, a spring retainer that is slidably fitted onto the shaft, and a dial that is screwed onto the shaft and moves the spring retainer forward and backward by rotation.The mechanism is made up of a dial that is slidable on the shaft. A mechanism consisting of the above-mentioned spring holder to be fitted, a dial rotatably attached to the shaft and equipped with an end cam that engages with the spring holder, the above-mentioned spring holder to be slidably fitted to the shaft, and an intermediate mechanism. A mechanism consisting of a lever whose part is pivoted to a mounting member and whose one end is engaged with a spring holder, and a cam which engages with the other end of the lever and is manually operated;
Examples include a dial that is screwed onto the shaft and also functions as a spring holder.In addition, in the type that uses a leaf spring, one side of the lever whose middle part is pivoted to the mounting member is a plate. As a spring,
Examples include a mechanism consisting of a cam or pin that engages with the other side of the lever and is manually rotated or slid.

Examples of manual operating mechanisms include dials and levers that are fixed to the shaft end of the operating shaft and are used to rotate the operating shaft, as well as push buttons and two buttons that are integrally connected to the button. Alternatively, it is possible to use a push button mechanism consisting of a pin that fits into the bifurcation and is provided on a link mechanism that is connected to the operating shaft.

The thread loosening means is formed, for example, in a pin protruding in the radial direction from the operating shaft, and in one of the pair of tension discs or a spring catcher with which the spring is engaged, and
It is composed of a cam groove that the pin engages with, and a rotation stopper such as a pin that engages with the tone plate or spring receiver in which the cam groove is formed and fixes the tone plate or spring receiver in the rotational direction. .

Embodiment The embodiment shown in FIG. 1 shows a thread tension device for the looper thread 1 of the overlock sewing machine shown in FIG. The operating shaft 4 is formed in this part.
is horizontally mounted rotatably, and a pair of tone plates 5, a coil spring 6, a spring receiver plate 7, and a spring retainer 8 are fitted in order to the operating shaft 4 protruding from each mounting portion 3a, and both tone plates 5 are fitted. The rotation of the spring receiver plate 7 is stopped by the protruding ends of the stop shafts 9 extending from the mounting parts 3a, and the operating shafts 4 protruding from the respective mounting parts 3a. A pin 11 that engages with a tapered cam groove 10 formed in the circumferential direction of the spring receiver plate 7 is provided protrudingly (second to fifth pins).
(See figure) An operating lever 12 for rotating the shaft is fixed to the end of the shaft protruding from the sewing machine main body 2. A pair of vertical shafts 13 and a horizontal shaft 14 perpendicular to both vertical shafts are also attached to the board 3.
A plate cam 15 is slidably attached to the plate cam 15, and a pair of dials 16 are rotatably attached to the horizontal shaft 14. Although not shown, a pinion provided on each dial 16 is engaged with a rack provided on the plate cam 15. ing.
A lever 17 is further pivotally attached to the base plate 3, and a pin 18 protruding from one end of the lever 17 is attached to the end surface of the plate cam 15.
The other end is engaged with the spring presser 8, and when the plate cam 15 slides along the vertical axis 13 via the pinion/lack mechanism by rotating the dial 16, the lever 17 pivots and the spring presser 8 The operation axis 4
It is designed to advance and retreat along the

When loosening the thread in this device, the operating lever 12 is rotated to turn the operating shaft 4 1/4 turn counterclockwise from the state shown in FIG. 4, and the pin 11 is released from the cam groove 10 ( Figure 2). As a result, the spring receivers 7 are separated from the tension plates 5 against the action of the coil springs 6 (FIG. 3). When releasing the thread loosening and applying tension, perform the reverse operation to the above. That is, by operating the operating lever 12, the pin 11 is rotated 1/4 turn in the opposite direction, and the cam groove 1 is rotated.
It returns it to 0 (Figures 4 and 5).

In the embodiment shown in FIG. 6, the operating shaft 22 is rotatably attached to a pair of mounting portions 21a which are bent from the base plate 21 and opposed to each other, and the operating shaft 22 is operated by the shaft end protruding from the sewing machine body. While the lever 23 is fixed, a pair of adjustment plates 24 are fitted to the left and right shaft parts protruding from each mounting part 21a, and a pin protruding in the radial direction is provided. The rotation is stopped by a horizontally suspended stop shaft 26, and of the pair of tension discs 24, the outer tension disc engages with a leaf spring to be described later and functions as a spring holder. It has a cam groove into which the pin fits. Although the pin and cam groove are not shown here, they have the same structure as in the above embodiment. The substrate 21 also includes
A pair of levers 29 are pivoted and a pair of vertical shafts 28 are vertically suspended, and a leaf spring 29a attached to the lever 29 in a cantilevered manner engages with the outer tone plate to cause the tone plate to move. It is pressed against the inner tone plate. On the other hand, a cam plate 31 is attached to each vertical shaft 28 and is slidably operated by a camera 30, and a roller 29b pivotally supported by a lever 29 is engaged with the cam plate 31.
The lever 29 pivots as the leaf spring 31 slides.

In the case of this device, thread loosening is performed in the same manner as described above.

In each of the above embodiments, the operating lever must be rotated not only when loosening the thread but also when releasing the loosening of the thread. If it is biased as much as possible, it will be possible to automatically move back by the action of the spring when releasing the loosened thread.

Figures 8 and 9 show another example of the manual operation mechanism, in which a pair of fixing pins 38 arranged vertically in vertical holes 37 are fitted into a key-shaped operating plate 36 with a push button 35 fixed to the upper end. By being guided by the pin, the actuating plate 36 can slide vertically over a certain range within the vertical hole 37. The actuation plate 36 also has a fork 39 bent on its side, and a pin 42 on one side of a bell crank lever 41 whose intermediate portion is pivoted to a fixing member (not shown) is fitted into the fork 39. The other side of the crank lever and an arm 44 fixed to the operating shaft 43 are connected by a link 45. Although not shown in the figure, the bell crank lever 41 is equipped with a spring that biases the lever clockwise in FIG. It protrudes to the upper limit position. This device is constructed as described above, and when the push button 35 is pushed to the lower limit position against the action of the spring, the bell crank lever 4
1 rotates counterclockwise in FIG. 9, and rotates the operating shaft 43 counterclockwise via the link 45. The thread is then loosened. When the presser foot on the push button is released, the spring moves back and forth, releasing the thread loosening and allowing the tension to work.

In the above embodiment, the operating shaft is rotated by operating a push button via a link mechanism consisting of an operating plate, a bell crank, a link, and an arm. It is also possible to use a link mechanism in which a protruding pin is provided, the pin is fitted into two prongs, and the actuating plate and arm are directly connected.

In the above embodiment, the push button is always urged to protrude by a spring, but it is possible to move the push button up and down without using a spring. In this case, as shown in FIGS. 9 and 10, a second arm 4 is attached to the operating shaft 43 adjacent to the arm 44.
8 is fixed, and a pin 49 is provided protruding from the tip of the arm, so that when the thread is loosened, the pin 49 is at the position indicated by the dashed-dotted line, which is the action area of the release lever 52 attached to the upper shaft or rotating shaft 51. It is preferable that the release lever 52 be pushed out of the action area of the release lever 52 at the same time as the sewing machine is actuated. As a result, the push button can be automatically protruded by driving the sewing machine without having to pull up the push button.

Effects of the invention As described above, the thread tension device of the present invention is a thread tension device for an overlock sewing machine in which a plurality of thread tension devices are provided on one shaft to form a unit. This system is designed to loosen the threads of multiple thread tension devices at the same time by rotating a common shaft, so thread loosening can be done quickly and easily. Since the shaft to which the thread tension device is attached is used, the structure is simplified and the entire device becomes compact.
Further, the thread tension of each thread tension device can be adjusted without affecting the thread tension of other devices.

[Brief explanation of the drawing]

Fig. 1 is a front view of the thread tension device according to the present invention, Fig. 2 is a sectional view showing the state in which the pin is fitted into the cam groove, Fig. 3 is a partial sectional view of the main part, and Fig. 4 is a sectional view showing the pin fitted into the cam groove. 5 is a partial sectional view corresponding to FIG. 4, FIG. 6 is a front view of another embodiment, and FIG. 7 is a diagram of an overlock sewing machine equipped with this device. 8 is a front view of a main part of another embodiment, FIG. 9 is a side view of the same main part, and FIG. 10 is a side view of a reciprocating mechanism. 3, 21... Board, 4, 22, 43... Operation axis, 5, 24... Tension plate, 7... Spring receiver plate,
9, 26... Stop shaft, 10... Cam groove, 11...
Pin, 12, 23... Operating lever, 35... Push button, 36... Operating plate, 41... Bell crank lever, 44, 48... Arm, 52... Release lever.

Claims (1)

[Claims for Utility Model Registration] (1) An operating shaft that is rotatably supported only about a fixed axis is provided with a pair of tone plates and one of the pair of tone plates that is engaged with the control shaft. a spring means for pressing the plate against the other plate; an adjusting means for adjusting the spring force of the spring means; and a spring means operated by rotation of an operating shaft,
A plurality of thread tension devices each consisting of a thread loosening means for moving one of the tension discs or the spring catch plate in the axial direction of the operating shaft against the action of the spring means and releasing the presser pressure between the tension discs are installed at appropriate intervals. When the manual operation member is assembled and the manual operation member is connected, and the operation shaft is rotated by operating the manual operation member, the thread loosening means of each thread tension device is activated, and the thread loosening of each thread tension is performed simultaneously. Features a thread tension device for overlock sewing machines. (2) The thread loosening means is formed of a pin protruding in the radial direction from the operating shaft, and one of the pair of tension discs or a spring catcher with which the spring is engaged, and the pin is loosened by the rotation of the operating shaft. a cam groove to engage;
A thread tensioner for an overlock sewing machine according to claim 1, comprising a rotation stopper that engages with a tension plate or a spring catcher in which the cam groove is formed to restrict the rotational movement of the plate. Device. (3) The thread tension device for an overlock sewing machine according to claim 2, wherein the manual operation member is a lever fixed to the operation shaft. (4) The thread tension device for an overlock sewing machine according to claim 1, wherein the manual operation member is a push button and is connected to the operation shaft via a link mechanism. (5) The thread tension device for an overlock sewing machine according to claim 3 or 4, wherein the operating shaft is biased by a spring to a position where the tension is applied.