JPS6116477B2 - - Google Patents

Description

Detailed Description of the Invention This invention provides a presser foot that presses against the upper surface of the throat plate in the sewing section of the sewing machine, and an upper feed dog that performs four cloth feed movements in conjunction with the main shaft of the sewing machine on the throat plate adjacent to the presser foot. The present invention relates to a presser foot lifting device for an upper feed sewing machine, which maintains a presser foot and an upper feed dog apart from each other above a throat plate in connection with manual operation.

Conventionally, the presser foot lifting device for this type of top feed sewing machine has been designed to simultaneously rotate the top feed arm, which holds the top feed dog at its tip, and the presser foot, which holds the presser foot at its tip, in conjunction with the depressing operation of a pedal, etc. There is a known device in which the upper feed dog and the presser foot are raised equally by a certain amount. According to this, the lower surface of the upper feed dog rises with the lower surface protruding downward from the lower surface of the presser foot, and when loading and unloading cloth, This protruding lower surface of the upper feed dog gets caught and makes the work cumbersome.In addition, in overlocking sewing machines, the presser foot that supports the presser foot is normally supported on the machine frame so that it can rotate around a vertical axis, and the sewing machine is sewn. The machine has a mechanism to release the presser foot laterally from the presser foot, but as mentioned above, when lifting the presser foot, the amount of rise of the upper feed dog and the presser foot is equal, so the presser foot is rotated horizontally when the presser foot is raised. In order to do this, it is necessary to push down only the presser foot to prevent the presser foot from engaging with the upper feed dog before rotating, which makes the work complicated and has the drawback of significantly reducing work efficiency.

The purpose of this invention is to eliminate the drawbacks of the above-mentioned conventional devices.

To explain an embodiment of the present invention, a support shaft (not shown) having a horizontal axis perpendicular to the cloth feeding direction (FIG. 1A) is installed at the rear of the sewing machine.
The intermediate part of the is rotatably supported on the machine frame by a bearing (not shown), and an effecting body 1 having a pin 1a parallel to the axis A is fixed to one end of the support shaft, and a holding body is attached to the other end. 2 is fixed, and a presser arm 3 is supported at the upper end of the holder 2 so as to be rotatable about a vertical axis. At the tip of the presser arm 3, there is a presser foot 4 formed with two rows of slots 4a into which tooth portions 23a of an upper feed dog 23, which will be described later, are fitted. The presser arm 3 is supported rotatably around the horizontal line that intersects with the cloth feed line as shown in the figure.
is always subjected to an elastic force that presses the presser foot 4 against a throat plate (not shown).

A working arm 5, a supporting arm 6, and a connecting arm 7 are rotatably supported on a bearing that supports a supporting shaft.

The working arm 5 is formed with a long hole 8 in the shape of an arc centered on the axis A of the support shaft at the base end, and the pin 1a of the working body 1 is inserted into the working arm 5.
loosely fit into the long hole 8. The working arm 5 has a protrusion 9 protruding from the upper part of the base end facing above the connecting arm 7, and one side edge of the protrusion 9 is bent upward to form a screw hole 10a substantially along the cloth feeding direction. It is referred to as a connecting portion 10.

An operating lever 12 whose base end is fixed to a support shaft 11 rotatably supported on the machine frame along the cloth feeding direction has its tip connected to an operating body such as a pedal (not shown), and its intermediate part connected via a connecting rod 13. and is connected to the tip of the working arm 5. A screw 15 that can be adjusted by screwing into a horizontal support plate 14 fixed to the machine frame has its tip engaged with the upper edge of the operating lever so as to define the initial position of the operating lever 12, and is fitted onto the support shaft 11. The coiled spring 16 provides an elastic force that rotates the operating lever 12 so that the upper edge of the operating lever 12 engages with the tip of the screw 15.

The connecting arm 7 has a hole 1 that projects upward and corresponds to the connecting portion 10 of the working arm 5 and allows communication with the screw hole 10a.
It has a connecting part 17 formed with a shape 7a, and an action part 18 which protrudes toward the front in the cloth feeding direction and is bent into a substantially Z-shape. In FIG. 2, the stepped screw 19 has a distal end bulged in the outer circumferential direction to form a receiving portion 19a, and the distal end shaft portion 1
9b loosely fit into the hole 17a of the connecting arm 7, and
A proximal threaded portion 19c having a larger diameter than the one shown in FIG.
0 is wound and compressed between both end faces of the receiving part 19a and the connecting part 17, whereby the connecting part 17 is held between the end face of the threaded part 19c and the coiled spring 20, and the connecting arm 7 and the working arm 5 are separated. It can be rotated almost integrally.

The upper feed arm 21 is a horizontal swing arm 2 that swings about an axis that intersects with the cloth feed direction in conjunction with the main shaft of the sewing machine.
2. The rear end in the cloth feeding direction is rotatably connected to the lower end, and the upper feed dog 23 is fixed to the tip.
a is placed so as to face the slot 4a of the presser foot 4. A guide cam 21a is formed on one side end surface of the intermediate portion of the upper feed arm 21, and is a cam surface that can be engaged with the upper end of the operating portion 18 of the connecting arm 7. This guide cam 21a prevents the upper feed dog 23 from rising due to the rotation of the connecting arm 7, which will be described later, in all the swinging positions of the horizontal swinging arm 22, that is, in the entire horizontal movement range of the upper feed arm 21. The cam surface is formed so that it always has a constant amount with respect to the rotation angle of 7.

The support arm 6 has a protrusion 24 that protrudes upward and has a screw hole 24a substantially along the cloth feeding direction, and a support portion 25 that protrudes toward the front in the cloth feed direction and is connected to a vertical swing mechanism to be described later. The rotational position of the support arm 6 is defined by adjusting the screw 26 which is screwed into the support arm 24a and whose tip engages with the machine frame. screw 2
6. The buffer body 27 fixed to the machine frame facing the tip is
This is to cushion the tip of the screw 26 from colliding with the machine frame when the support arm 6 swings, and is made of a material such as rubber.

A rocking body 28 is rotatably connected to the tip of the support portion 25 of the support arm 6 about an axis intersecting the cloth feeding direction.
is connected to the tip of the swing link (connection means) 29 below the rotation axis so as to be rotatable about an axis parallel to the rotation axis, and is located before the rotation axis in the cloth feeding direction. At the remote position, a piece 30 serving as a holding member is supported so as to be rotatable about an axis parallel to the rotation axis. The swing link 29 has its base end connected via a link 51 to a knife drive shaft 50 that swings in conjunction with the main shaft of the sewing machine, and swings along the arrow direction A in FIG. The vertical section is approximately U-shaped so that the upper and lower end surfaces of the intermediate portion are sandwiched and slidably fitted. This swinging body 28, swinging link 2
9. The pieces 30 constitute a vertical swing mechanism.

Reference numeral 31 designates a bifurcated guide body fixed to the machine frame and slidably fitted onto both side end surfaces of the tip of the upper feed arm 21. Reference numeral 32 denotes an adjustment means that engages with the upper part of the tip of the support part 25 of the support arm 6 and adjustably applies downward elastic force. The body 33 is arranged and the support part 25
Fixed to.

Although not shown, the link 51 has a structure in which the connecting hole for the knife drive shaft 50 is made into an elongated hole so that the connecting position can be adjusted and the swing stroke can be adjusted.

The present invention has the above structure, and its operation will be explained next.

In the swing mechanism, the swing arm 22 swings around its upper end, thereby swinging the upper feed arm 21 in the horizontal direction, and the swing link 29 swings along arrow A, causing the swing body 28 to swing. Support part 25 of support arm 6
The piece 30, which is supported by the swinging body 28 and swings around the connection point with the top feed arm 21, swings in the vertical direction.
to communicate. As a result, the upper feed arm 21 performs four feed movements by combining vertical and horizontal directions. A thick part of the fabric such as a step moves between the presser foot 4 and the throat plate, and the upper feed dog 23 is lifted up. Since the support arm 6 is rotatably supported by the support portion 25 of the support shaft 6, the support arm 6 can be rotated counterclockwise (FIG. 1) against the elastic force of the adjustment means 32 around the axis A of the support shaft. It absorbs that lifting force. When the support arm 6 returns after passing through the thick part of the fabric, the tip of the screw 26 that is screwed into the support arm 6 collides with the machine frame, the adjustment means 32, and the support part 25, but there is a shock absorber 2 between them.
7,33 prevents vibration and noise.

The support shaft is given a rotational force in the clockwise direction in FIG. 1 by the elastic force acting on the presser arm 3 so as to press the presser foot 4 against the throat plate, and is also pressed against the tip of the support portion 25 of the support arm 6. Due to the elastic force of the adjusting means 32, the tooth portion 23a of the upper feed dog 23 is pressed against the throat plate via the upper feed arm 21 that engages with the support arm 6.

Further, since the spring 20 of the step screw 19 is compressed between the receiving part 19a and the connecting part 17, the connecting arm 7 receives an elastic force in the clockwise direction in FIG. It is always disengaged from the surface.

When the presser foot 4 is in pressure contact with the throat plate and the upper feed dog 23 is lowered, the support shaft and the working arm 5 are connected to the pin 1a.
is the initial position located in the middle of the long hole 8 (Fig. 4), and the position of the pin 1a at this time is the fourth position of the long hole 8.
The distance (△t) to the right end of the figure is set corresponding to the amount of rise of the upper feed arm 21 required for the lower end surface of the tooth portion 23a of the upper feed dog 23 to rise from the upper end surface of the presser foot 4, and the operating lever The operating arm 5 is rotated via the operating lever 12 by advancing and retracting the screw 15 that restricts the pin 12, so that the pin 1a is at the initial position.
and the right end of the elongated hole 8 can be adjusted.

Press down the operating body such as a pedal to release operating lever 1.
2 is rotated against the spring 16, the working arm 5 is rotated counterclockwise (FIG. 1) about the axis A of the support shaft, and the connecting arm 7, which is in a connected state at the connecting parts 10 and 17, rotate substantially simultaneously, and the operating portion 18 that engages with the guide cam 21a pushes up the upper feed arm 21.
The upper feed arm 21 rotates around the axis of connection with the swing arm 22 so that the tip thereof rises, and the upper feed tooth 2 at the tip rotates.
Raise the No. 3 tooth 23a above the throat plate. At the beginning of rotation of the working arm 5, the support shaft is stationary because no acting force is transmitted thereto. The long hole 8 is opened by rotating the working arm 5.
The right end of FIG. 4 approaches the pin 1a, and the upper feed dog 23
When the lower end surface of the toothed portion 23a rises higher than the upper end surface of the presser foot 4 (FIG. 8), the pin 1a engages with the right end surface of the elongated hole 8 (FIG. 5), and then the operating body 1
(Support shaft) is connected to the working arm 5 and rotates together, and the presser arm 3 rotates together with the support shaft to raise the presser foot 4 from the throat plate (FIGS. 6 and 9). Due to the cam shape of the guide cam 21a with which the action portion 18 of the connecting body 7 engages, the amount of rise of the upper feed dog 23 during the initial rotation of the connecting arm 7 is kept constant regardless of changes in the swinging position of the swinging arm 22. I have to.

Note that, in place of the swinging mechanism of this embodiment, a mechanism as shown in FIGS. 10 and 11 may be used as a second embodiment. That is, 33 is a sewing machine frame, 34 is a stepped portion 34a which is slidably supported in the vertical direction but not rotatable with respect to the machine frame 33, and which bulges outward in the radial direction at the upper end, and a step portion 34a at the lower end that is approximately on a line passing through the axis. Support plane 34b cut out in
35 is a cylindrical holding body formed with a holding body 3 at the lower end.
4. A shaft portion 35a that loosely fits on the upper end, and a threaded portion 35 on the upper end.
36 is a pedestal whose base end is fixed to the machine frame 33 and the tip is screwed into the threaded part 35b of the adjustment shaft 35; 37 is fixed above the pedestal 36 and has the threaded part 35b;
The nut 38 is screwed into the stepped portion 34 of the holding body 34.
This is a shock absorber placed between a and the machine frame 33. 39
is a support shaft fixed to the support plane 34b and having an axis substantially on the axis of the holder 34 and intersecting with the cloth feeding direction;
Reference numeral 40 denotes a rocking body whose upper end is rotatably supported around the support shaft 39 and whose lower end is rotatably connected to the rocking link 29. 41 and 42 are arranged to sandwich the axis of the support shaft 39 and are spaced apart in the cloth feeding direction, and support the swinging body 40 so as to be rotatable about an axis parallel to the support shaft 39. A roller 43 that can be engaged with the end face is supported substantially on the axis of the holding body 34 so as to be rotatable with respect to the rocking body 40 about an axis parallel to the support shaft 39, and there is a roller 43 between the rollers 41 and 42. This roller is capable of holding the upper feed arm 21 and engaging with its lower surface.

Reference numeral 44 denotes a coiled spring compressed and disposed inside the holder 34 between the lower end of the adjustment shaft 35 and the upper end of the swinging body 40 via the buffer 45. Note that the support arm 6 is not required in the mechanism of this embodiment.

In such a configuration, the upper feed arm 21 is guided by the rollers 41, 42, and 43 and swings in the horizontal direction by the swing of the swing arm 22, and the swing body 40 is supported by the swing of the swing link 29. The upper feed arm 21, which swings around a shaft 39 and is held between rollers 41, 42, and 43, swings in the vertical direction.
As a result, the upper feed dog 23 at the tip of the upper feed arm 21 performs four feed movements. When the thick portion of the cloth moves to the tooth portion 23a of the upper feed dog 23, the upper feed dog 23 is lifted, but the rollers 41, 4 that engage with the upper feed arm 21
2, the rocking body 40 pushes up the holding body 34 against the spring 44, allowing the upper feed arm 21 to rotate. When the upper feed arm 21 returns after the thick part of the cloth passes through, the shock between the holding body 34 and the machine frame 33 and between the spring 44 and the rocking body 40 is buffered by the shock absorbers 38 and 45, thereby reducing vibration and noise. prevent. Further, when lifting the presser foot, similarly to the swinging mechanism of the present embodiment, the upper feed arm 21 (upper feed tooth 23) rises by a certain amount.

Moreover, the swing mechanism of the third embodiment shown in FIG. 12 may be used instead of the second embodiment. That is, the supporting plane 34b at the lower end of the holding body 34 is extended downward, and the middle part of the L-shaped connecting link 47 is rotatably connected to the lower end. The roller 4b is engageably supported so as to be rotatable about an axis that intersects with the cloth feeding direction. Further, the tip of the swing link 29 is rotatably connected to the lower end of the connecting link 47, and a piece 30 (configuration similar to this embodiment) fitted to the upper feed arm 21 is rotatably connected to the upper end of the connecting link 47. Support movably.

In such a configuration, the horizontal swinging of the upper feed arm 21 due to the swinging of the swinging arm 22 is allowed by the piece 30, and the swinging of the swinging link 29 causes the connecting link 4 to move horizontally.
7, the piece 30 swings up and down, causing the upper feed arm 21 to swing in the vertical direction, and the upper feed dog 23 performs four feed movements in the same manner as described above. Upper feed dog 2 of thick cloth part
When the upper feed dog 23 is pushed up by the movement toward the tooth portion 23a of No. 3, the holding body 3
4 is pushed up against the spring 44, thereby allowing the upper feed arm 21 to rise.

Also, when lifting the presser foot, the guide cam 2
The upper feed arm 21 (upper feed dog 23) is raised by a certain amount in advance of the presser arm 3 (presser foot 4) by the action portion 18 of the connecting arm 7 that engages with the upper feed arm 1a.

Further, in this embodiment, the support arm 6 and the connecting arm 7 are supported on a bearing that is rotatably fitted loosely in the middle part of the support shaft, and the working arm 5 and the holder 2 are fixed to both ends of the support shaft. However, the working arm 5 and the holder 2 may be fixed to both ends of the support shaft, and the support arm 6 and the connecting arm 7 may be rotatably supported directly on the support shaft.

Further, in this embodiment, the working arm 5, the supporting arm 6, the connecting arm 7, and the holding body 2 that supports the presser arm 3 are all supported on the axis A of the supporting shaft, but the supporting arm 6,
The connecting arm 7 may be rotatably supported on another axis having an axis parallel to the support shaft, and may be connected to rotate in conjunction with the working arm 5.

Further, in this embodiment, the guide cam 21a is formed on the upper feed arm 21 so as to engage the tip of the acting portion 18 of the connecting arm 7, but the tip of the acting portion 18 is provided with a roller that engages with the guide cam 21a. The upper feed arm 21 may be rotatably supported, and the upper surface of the tip of the operating portion 18 may be shaped like a cam that produces the same effect as a guide cam.
A roller or a pin may be arranged at the engaging portion of the holder.

Furthermore, in this embodiment, the working body 1 is fixed to the support shaft and the pin 1a of the working body 1 and the elongated hole 8 of the working arm 5 are fitted into each other. A pin may be provided adjacent to the support shaft and protrude from the holder 2 in the axial direction, and this pin may be fitted into the elongated hole 8 of the working arm 5. A long hole is formed in 2 and the working arm 5
It is also possible to form pins on the parts and arrange them so as to produce the same effect as in this embodiment.

Further, in this embodiment, the action portion 18 of the connecting arm 7 engages with the upper feed arm 21, and rotates the support arm 6 around the axis A of the support shaft via the upper feed arm 21, thereby causing the upper feed tooth to rotate. 23 is shown, the action part 18 is engaged with the lower end surface of the tip of the support part 25 of the support arm 6 to directly rotate the support arm 6, and the upper feed dog 23 is raised via the upper feed arm 21. may be made to rise.

As described above, according to the present invention, the working arm 5 has a proximal end supported rotatably about the rotation axis of the presser arm, and a distal end horizontally spaced apart from the base end connected to a manual operation member, and the working arm 5. a connecting means 7 disposed between the upper feed dog and the upper feed arm to raise the upper feed dog from the throat plate in relation to the rotation of the working arm; By providing the operating means 1a and 8 that engage with each other and establish a connected state at the rotational angle of the operating arm corresponding to the movement of the upper feed dog to the presser foot, the upper feed dog rises in advance of the presser foot when the operating means is operated. , the upper feed dog is raised until the lower surface of the upper feed dog is located above the upper surface of the presser foot, and then the presser foot is connected to the operating means and begins to rise, so the upper feed dog is always positioned above the lower surface of the presser foot. The upper feed dog is located above the presser foot, so the presser arm can be rotated horizontally without having to push down the presser foot, which significantly improves work efficiency. can get.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the upper feeding device and lifting device of this embodiment, Fig. 2 is a front view of the upper feeding arm lifting mechanism of the upper feeding device, and Fig. 3 is a front explanatory view of the swinging mechanism of the upper feeding device. , Figures 4 to 6 are explanatory diagrams explaining the connection state of the working arm and the support shaft, Figures 7 to 9 are explanatory diagrams of the upper feed arm lifting mechanism corresponding to Figures 4 to 6, and Figure 10 is the second A front view of the upper feeding device of the embodiment, FIG.
FIG. 12 is a perspective view of the main part of the upper feed device of the third embodiment.

Claims (1)

[Scope of Claims] 1. A presser foot is fixed to the tip and supported on the machine frame so as to be rotatable about a horizontal axis perpendicular to the cloth feeding direction so as to move the presser foot toward and away from the throat plate. A presser arm 3 which receives an elastic force in the direction of rotation presses against the plate, and an upper feed dog which faces the throat plate and is close to the presser foot is fixed at the tip, and the plate is held parallel to the axis of rotation of the presser arm and is connected to the sewing machine. An upper feed arm 21 that is rotatable about an axis that oscillates along the cloth feeding direction in conjunction with the main shaft, and swing mechanisms 28 and 29 that are interlocked with the main shaft of the sewing machine and that swing the tip of the upper feed arm in the vertical direction. , a working arm 5 whose base end is rotatably supported around the rotational axis of the presser arm and whose distal end spaced apart horizontally from the base end is connected to a manual operating member; the working arm and the upper feeder; a connecting means 7 disposed between the working arm and the upper feed dog to raise it above the throat plate in relation to the rotation of the working arm; and a connecting means 7 arranged in relation to the working arm and the presser arm to raise the upper feed dog above the presser foot. Acting means 1 that engage with each other at a rotational angle of the operating arm corresponding to
A presser foot lifting device for a top-feed sewing machine equipped with a, 8, and.