JPS6234535Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial field of application This invention relates to an upper feed mechanism of a sewing machine equipped with an upper feed dog that performs four movements symmetrical with the lower feed dog to feed cloth in cooperation with the lower feed dog. .

Prior Art Sewing machines equipped with an upper feed mechanism are known, but in the conventional upper feed mechanism, in order to move the upper feed dog up and down, a cam that rotates in conjunction with the main shaft is attached to the upper feed table to which the upper feed dog is attached. As the sewing machine speeds up, the upper feed bar cannot accurately follow the cam, causing a jumping phenomenon, and the collision noise caused by the upper feed bar colliding with the cam. vibrations tended to occur. Some models have the rollers of the crank that swings up and down engaging the upper feed table, but the rollers separate from the upper feed table near the bottom dead center during the downward rotation of the crank, and the rollers move away from the upper feed table as the crank rotates upward. As the sewing machine moves, it engages with the upper feed base, and when it engages, it collides, causing collision noise and vibration, and these collision noises and vibrations tend to become more intense as the sewing machine speeds up. It was hot.

Problems to be solved by this invention This invention solves the above problems and provides an upper feed mechanism for a sewing machine that can smoothly feed cloth without generating impact noise or vibration even when operated at high speed. purpose.

Means for Solving the Problems The present proposal therefore consists of an upper feed mechanism consisting of a first crank fixed to the feed shaft and swinging in the front and back direction, a lever to which the upper feed dog is attached, and the first crank. A feed lever rotatably connects the lever, a second crank fixed to the vertical adjustment shaft and swings in the vertical direction, and a second crank rotatably connects the second crank and the feed lever. link and
A leaf spring that engages with the lever and biases the lever in one rotation direction to push the upper feed dog downward; and a regulating means that restricts the lowering of the upper feed dog due to the action of the leaf spring. This is characterized in that the upper feed dog is moved up and down by a link mechanism.

Embodiment In FIG. 1, reference numeral 1 denotes a feed lever rotatably supported by a crank pin 4 protruding from a crank 3 fixed to a feed shaft 2 at the rear, and reciprocated in the front-rear direction by the rocking of the crank 3. A lever 6 having an upper feed dog 5 fixed to one end thereof is rotatably supported in the intermediate portion of the feed lever 1 at its distal end.
The lever 6 is moved to the first position by a leaf spring 7 that engages with the other end.
It is urged to rotate clockwise in the figure, comes into elastic contact with a pin (not shown) that protrudes laterally from the tip of the feed lever, and is connected to the feed lever 1 so that it always moves as one unit. . Thus, the upper feed dog 5 moves back and forth in synchronization with the lower feed dog 8 due to the swinging of the feed shaft 2.

The feed lever 1 also has a vertical adjustment shaft 9 at its tip.
It is connected by a crank 10 and a link 11, which are fixed to each other, and swings in the vertical direction about the pin 4 as a fulcrum when the crank 10 swings.
At the same time, as described above, the lever 6 also moves up and down while being pressed against a pin (not shown), causing the upper feed dog 5 to move up and down. As described above, the upper feed dog 5
performs four movements as known in the art by a combination of the vertical movement and the fore-and-aft movement, and feeds the cloth in cooperation with the lower feed dog.

The vertical adjustment shaft 9 is oscillated by the existing operating shaft of the sewing machine. In the illustrated device, the knife shaft 16 of the upper knife 15 is used to swing the vertical adjustment shaft 9. The transmission mechanism that transmits the movement of the knife shaft 16 to the vertical adjustment shaft 9 is equipped with a mechanism that adjusts the amount of swing of the vertical adjustment shaft 9. That is, a block 18 is attached to a crankshaft 17 that protrudes laterally from the female shaft 16 so that its position can be adjusted, and a square piece 20 that is pivotally supported by pins 19 that protrude from both sides of the block 18 is attached to a vertical adjustment shaft 9. It is slidably fitted into each fork 22 of a fork lever 21 provided to protrude laterally. However, in FIG. 2, the knife shaft 16 rotates counterclockwise and the upper knife 1
5 rises, the vertical adjustment shaft 9 rotates clockwise, rotates the crank 10 downward, and the link 1
1, the feed lever 1 is rotated downward about the crank pin 4, and the upper feed dog 5 is lowered. The knife shaft 16 rotates clockwise and the upper knife 15
Conversely, when the upper feed dog 5 is lowered, the upper feed dog 5 is raised.
In this way, the upper feed dog 5 moves up and down by the rocking of the knife shaft 16, and its stroke can be adjusted by changing the mounting position of the block 18.
That is, when the block 18 is moved to the right side in FIG. 2, the swing range of the vertical adjustment shaft 9 relative to the knife shaft 16, which swings at a constant angle, becomes smaller, and when the block 18 is moved to the left side, it becomes larger. It is. In order to change the mounting position of the block 18, in this device, a screw 23 is screwed onto the block 18, and by loosening the screw, the block 18 can slide on the crankshaft 17.
Further, when the screw 23 is tightened, the block is fixed. The mounting position of the block may be adjusted by pivoting an operating lever to a pin projecting upward from the block and rotating the operating lever in the usual manner.

Also, contrary to the above device, the crankshaft may be attached to the adjustment shaft and the forked lever may be attached to the female shaft. A link connected to the actuating shaft via a crank lever mechanism and connecting the crank and the lever may be configured such that the distance to the rotation center of the attachment portion of the link to the crank can be adjusted.

Further, a crankshaft 17 protruding from the female shaft 16 is constituted by a fork 22 of a forked lever 21 attached to the vertical adjustment shaft 9 at the lower limit of its swing range, and the groove in which the block 18 is fitted is connected to the crankshaft. 17, the fork lever 21 will remain stationary at its lower limit position and will not move even if the block 18 is moved. Therefore, even if the vertical stroke of the upper feed dog is changed, The lowered position of the upper feed dog is always constant.

As in the embodiments described above, since the stroke in the vertical direction of the upper feed dog is adjustable, when sewing fabric with stepped portions, the stroke can be increased. While the same upward feed for the normal fabric is performed in the forward stroke when the cloth is lowered, it is possible to prevent the upper feed teeth from getting caught on the stepped portion when the cloth is raised and in the return stroke.

In addition, when sewing thin fabrics, by reducing the above-mentioned stroke, the vertical speed of the upper feed dog can be reduced, which reduces the impact force applied to the fabric and allows the feed dog to attach to the fabric. This can prevent scratches caused by.

Effect of the invention As described above, the upper feed mechanism of the present invention has the upper feed dog 5.
A spring 7 is provided which rotatably connects a lever 6 having a main shaft to a feed lever 1 that reciprocates back and forth in conjunction with a main shaft, and which acts on the lever 6 to apply a downward pressing force to the upper feed dog 5. Furthermore, a stopper means is provided to restrict the rotation of the lever 6 due to the action of the spring when the upper feed dog rises, and the upper feed plate is engaged with a cam or a roller of a crank that swings up and down. Unlike the conventional upper feed mechanism, which is compatible with the sewing machine, there is no collision noise or vibration even when the sewing machine is operated at high speed, and the fabric can be fed smoothly.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the upper feed mechanism of the sewing machine, and FIG. 2 is a side view of essential parts of the upper feed mechanism. 1...Feed lever, 4...Crank pin, 5...
...Upper feed dog, 6...Lever, 7...Leaf spring, 9...
...Vertical adjustment shaft, 16...Female shaft, 17...Crankshaft, 18...Block, 19...Pin, 20...
...Square piece, 21...Forked lever.

Claims (1)

[Scope of utility model registration request] A first crank 3 fixed to the feed shaft 2 and swinging back and forth, and a lever 6 to which an upper feed dog 5 is attached.
, a feed lever 1 rotatably connected to the crank 3 at one end and to the lever 6 at the other end, a second crank 10 fixed to the vertical adjustment shaft 9 and swinging in the vertical direction; second crank 10
, a link 11 whose other end is rotatably connected to the feed lever 1, and a link which is attached to the feed lever 1 and acts on the lever 6 to apply a downward pressing force to the upper feed dog 5. The spring 7 and the upper feed dog 5 as the second crank 10 rotates upward.
has a stopper means for regulating the rotation of the lever 6 due to the action of the spring 7 on the way up and causing the upper feed dog 5 to rise, and the upper feed dog is arranged in a four-way position symmetrical to the lower feed dog. Upper feed mechanism of a sewing machine that moves and feeds cloth in cooperation with the lower feed dog