JPH0521600B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application This invention works with an auxiliary tensioner to pull out the thread from the bobbin winder and slacken the thread on the feeding side of the tensioning device before the thread is picked up by the thread take-up. This invention relates to a sewing machine equipped with a thread take-up lever.

PRIOR ART As is well known, a thread take-up is a thread take-up machine that, when a needle thread loop caught by the tip of a hook passes through the hook, the tip pulls the needle thread loop and pays out the required amount of thread, while at the same time After the thread loop has passed through the hook, the thread is picked up, absorbing the slack in the needle thread loop, tightening the seam, and pulling out the necessary amount of thread from the spool through the tension device. Until this point, the thread is passed through a guide and a tension device, and is bent at each point, so the resistance when pulling out the thread from the spool is quite large, and therefore the tension when the thread take-up tightens the seam becomes large. Tension is normally adjusted by a tensioning device so that the seam is tightened appropriately, but the faster the sewing machine is, the more likely it is that overfeeding of thread, known as run-in, will occur, and after the thread is picked up by the thread take-up thread. However, if the stitches are not tightened enough, slack may remain, or if the needle thread loops are not absorbed sufficiently, the tip of the needle may catch the loops and cause thread breakage. If the presser foot pressure of the tension device is increased to prevent overfeeding of thread, the thread tension when tightening the seam will become larger and larger, causing thread breakage in threads with weak tensile strength, and thread breakage in threads with high elasticity. The amount of yarn taken up is absorbed by the elongation of the yarn, and the necessary amount of yarn cannot be pulled out from the spool. This problem is particularly likely to occur when using a sewing machine with a large swing width, which requires a large amount of thread to form the first stitch, or when using thread that is easily cut, such as ultra-fine silk thread.

Therefore, some high-speed sewing machines and embroidery sewing machines generally have an auxiliary tension 3 that engages with a cam 2 fixed to the upper shaft 1 to open and close the disc space in conjunction with the upper shaft 1, as shown in Fig. 4. When the thread take-up 4 descends, it closes the space between the plates to prevent overfeeding of thread to the hook, and when the thread take-up descends, it pushes down the thread S between the guide 5 and the auxiliary tension 3 to pull out the thread from the bobbin winder. Ok,
When tightening the seam, the slack thread is taken in through the auxiliary tensioner 3 which releases the space between the plates. According to this, it is possible to prevent overfeeding of thread when supplying thread to the hook when the thread take-up is lowered, and when the thread take-up is raised, the required amount of thread is supplied by absorbing slack through the auxiliary tensioner, and the thread is directly passed from the bobbin winder. Since there is less resistance than when pulling out the thread, the tension is smaller, making it less likely that the thread will break and the elongation of the thread will also be smaller.

Problems to be Solved by the Invention In the conventional sewing machine shown in FIG. , the tension device 8, the guide and the thread take-up spring, thread the thread through the thread take-up 4, lower it to the needle, and thread the thread into the eye of the needle. It is quite troublesome to have to change the direction of the thread every time to thread it. In particular, the color is like a sewing machine,
When embroidery is performed using various embroidery threads with different patterns and thicknesses, it is time-consuming and work efficiency is reduced when threads must be changed frequently.

This invention allows threading to be easily carried out on a sewing machine as described above.

Means for Solving the Problems That is, the present invention includes a thread loosening lever that reciprocates in conjunction with the upper shaft on the thread feeding side of the auxiliary tension;
Thread guides are arranged on both sides of the lever, and the thread loosening lever moves forward and engages the thread between both thread guides when the thread take-up feeds the thread to the hook, and one side is gripped and held by the auxiliary tension. The required amount of thread is pulled out from the bobbin winder by pressing down on the thread, and the thread is threaded into both thread guides simply by pulling the thread in one direction. According to this, there is no need to thread the thread under the thread take-up as in the past, and the thread can be threaded relatively easily regardless of the position or structure of the thread take-up.

The present invention also provides the auxiliary tension by arranging the auxiliary tension so that the plane passing between the tension discs passes through the thread insertion port leading to both thread guides, and by manipulating the thread in one direction within the plane, the auxiliary tension is connected to both thread guides and the auxiliary tension. The present invention is characterized in that threading can be carried out, and that the tension device is arranged so that the above-mentioned plane passes between its tension discs.

Yet another feature of the present invention is that a slit is formed in the sewing machine along the feeding direction through which the above plane passes, and by passing the thread through the slit and pulling it toward the front, the thread can be connected to both thread guides, the auxiliary tensioner, and the thread tension device. The reason is that it is possible to hang.

Embodiment As shown in FIG. 3, the sewing machine has a slit 11 formed in the top plate and the front wall along the feeding direction, a thread loosening lever 12, an auxiliary tensioner A, and a tension device B under the top plate, and a thread path. They are arranged in order perpendicular to the slits 11 (FIG. 1). Among these, the thread loosening lever 12 and the auxiliary tension A
will be explained based on FIG.

A first eccentric cam 15 and a second eccentric cam 16 are fixed to the upper shaft 14 with an appropriate interval in the axial direction.
A first fork 18 and a second fork 19 rotatably supported by a fixed shaft 17 fixed to the machine frame are fitted into the first eccentric cam 15 and the second eccentric cam 16, respectively,
As the upper shaft 14 rotates, the upper shaft 14 individually swings about the fixed shaft 17. A bell crank-shaped thread loosening lever 12 whose intermediate portion is pivoted to the machine frame is connected to the first fork 18 and a pitman 21, and swings up and down as the fork 18 swings. Thread guides 22 are arranged on both sides of the hook-shaped tip, and each guide 22 is hook-shaped and positioned below the slit, and is closely fixed to one edge of the slit. Guide plate 24
is supported by

Auxiliary tension A has a mounting plate 26 and a guide plate 24.
A pair of adjustment plates 28 and a bracket 29 are slidably mounted on the horizontal shaft 27, and the bracket 29 is mounted between the horizontal shaft 27 and a fixed collar 31. The tension plate 28 is normally pressed against the guide plate 24 by the closed coil spring 32, and the closed gap between the tension plates is positioned below the slit. The bracket 29 also has a tongue piece 33 protruding from the side, which engages one side of a bell crank lever 35 whose intermediate portion is pivoted to the machine frame, and the other end of the bell crank lever 35 is attached to a line. Forked 1 by spring 36
It is connected to 9.

The thread loosening lever 12 and the auxiliary tension A are constructed as described above, and when the first and second eccentric cams 15 and 16 are rotated by the upper shaft 14, the first and second forks 18 and 19 are fixed, respectively. It swings about the shaft 17, causing the thread loosening lever 12 and the bell crank lever 35 to swing up and down. The clockwise rotation of both the levers 12 and 35 in FIG. 2 is performed in synchronization with the lowering of the balance (not shown), and after the gap between the adjustment discs 28 of the auxiliary tension A is closed, the thread S between the thread guides 22 is loosened. is pushed down by lever 12,
A thread is pulled out from a spool (not shown). Note that the tension plate 28 of the closed auxiliary tension A is opened by the movement of the bracket 29 against the action of the coil spring 32 when the seam is tightened when the thread take-up is raised, and is pulled out from the bobbin winding by the thread loosening lever 12. The thread that was being used is retracted so that it does not become obstructed.

Tension device B, as shown in FIG.
The horizontal shaft 4 is horizontally suspended between the mounting plate 41 and the guide plate 24.
A pair of tension plates 43, a spring tray 44, and a cylindrical body 45 are slidably attached to the coil spring 4 inserted between the plate and the cylindrical body 45.
6 presses the adjustment plate 44 against the guide plate 24 via the protruding piece 47, and the slit 11 is inserted between the adjustment plates.
The spring pressure is applied to the cylindrical body 4 through an actuating plate 49 that is activated by rotating the dial 48.
5 is adjusted by sliding it on the horizontal axis. A bracket 51 is further slidably attached to the horizontal shaft 42, and by pressing down on a push button 52, the bracket 51 moves the spring receiving plate 44 to the right side in the figure against the action of the coil spring 46, and moves the spring receiving plate 44 between the adjustment plates. It's starting to open up. Since this structure is not the gist of the present invention, further detailed explanation will be omitted.

In the sewing machine configured as described above, the thread pulled out from the bobbin spool is hung on a guide (not shown) provided at the back of the sewing machine, passed through the slit 11, and pulled down in a downward motion toward the front side.
2. Threading to the auxiliary tension A and tension device B is performed, making it easier to thread the sewing machine. The thread is pulled toward the front through the slit, then pushed down, hung on a thread take-up spring 54 (FIG. 3), threaded through a thread take-up 55, and finally threaded through the eye of a needle 56.

[Brief explanation of the drawing]

Figure 1 is a plan view of the main parts inside the sewing machine, Figure 2 is a perspective view of the thread loosening lever and auxiliary tension, Figure 3 is a perspective view of the main parts of the sewing machine, and Figure 4 is a perspective view of the main parts of a conventional sewing machine. It is. 11...Slit, 12...Thread loosening lever, 1
4...Upper shaft, 22...Thread guide, 28...Tension plate, 29...Bracket, 32...Coil spring,
43... Tension plate, A... Auxiliary tension, B...
tension device.

Claims (1)

[Scope of Claims] 1. It has an auxiliary tension that opens and closes in conjunction with the rotation of the tension device and the upper shaft, and the tension plate closes between the tension discs when the thread thread take-up is fed out, and when the thread is tightened by the thread take-up. In a sewing machine that is to be opened, a thread loosening lever that reciprocates in conjunction with the rotation of the upper shaft and thread guides located on both sides of the lever are arranged on the thread feed side of the auxiliary tension. When the thread is fed out, it moves forward and engages the thread between the two thread guides, pushing down the thread held by the auxiliary tensioner and pulling out the thread from the bobbin winder. A sewing machine that allows threading to be done simply by operating in one direction. 2. A sewing machine that has an auxiliary tension that opens and closes in conjunction with the rotation of a tension device and an upper shaft, and the tension plate between the tension discs is closed when the thread thread take-up is fed out, but is opened when the thread take-up is tightened, A thread loosening lever that reciprocates in conjunction with the rotation of the upper shaft and thread guides located on both sides of the lever are arranged on the thread feeding side of the auxiliary tension. It moves forward and engages the thread between both thread guides, pushing down the thread held by the auxiliary tension and pulling out the thread from the bobbin winder. A sewing machine in which the plane that passes through is placed in a position that passes between the tension discs of the auxiliary tension, and the thread can be threaded onto both thread guides and the auxiliary tension simply by operating the thread in one direction. 3. A sewing machine that has an auxiliary tension that opens and closes in conjunction with the rotation of the tension device and the upper shaft, and the tension plate between the tension discs is closed when the thread thread take-up is fed out, but is opened when the thread take-up is tightened, A thread loosening lever that reciprocates in conjunction with the rotation of the upper shaft and thread guides located on both sides of the lever are arranged on the thread feeding side of the auxiliary tension. It moves forward and engages the thread between both thread guides, pushes down the thread held by the auxiliary tensioner, and pulls out the thread from the bobbin winder. Both thread guides, the auxiliary tension, and the tension device are placed in a position that passes between the tension plate and the tension plate of the tension device, and the thread can be threaded onto each thread guide, the auxiliary tension, and the tension device simply by operating the thread in one direction. Sewing machine. 4. A sewing machine that has an auxiliary tension that opens and closes in conjunction with the rotation of a tension device and an upper shaft, and the tension plate between the tension discs is closed when the thread thread take-up is fed out, but is opened when the thread take-up is tightened by the thread take-up, A thread loosening lever that reciprocates in conjunction with the rotation of the upper shaft and thread guides located on both sides of the lever are arranged on the thread feeding side of the auxiliary tension. It moves forward and engages the thread between both thread guides, pushes down the thread held by the auxiliary tension, and pulls out the thread from the bobbin winder.The tension of the thread insertion port leading to each thread guide and the auxiliary tension is controlled by the thread guide. A sewing machine in which both thread guides, an auxiliary tension, and a tension device are arranged so that the gap between the plates and the tension plate of the tension device are located below a slit formed in the sewing machine frame along the feed direction.