JPS6243510Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a cloth presser mechanism for a sewing machine in which the height of the presser foot that presses down the cloth follows the amount of depression of the pedal.

[Prior art]

As a conventional presser mechanism, one shown in FIG. 1 is known. FIG. 1 is a front view showing a presser mechanism of a conventional cycle sewing machine.

In FIG. 1, 1 is the main body of the sewing machine, 2 is a bed, and 3 is a throat plate fixed to the upper surface of the bed 2. 4 is a presser foot that presses the cloth against the throat plate 3 to determine the position of the cloth.

Reference numeral 6 has a mechanism for moving the feed table 7 with a feed plate to form the sewing shape. Reference numeral 8 denotes a push-down foot which is biased by a spring 10 around a shaft 9 in a direction to lower the presser foot 4.

11 is an eccentric cam, and rollers 11 are in contact with the circumferential surface of the eccentric cam.
a, levers 12, 13, and shafts 14, 15, which are linked so that the lever 17 rotates clockwise about a shaft 19 against the bias of a spring 16. Furthermore, this movement is lever 2
0 and 21, 22, a push-down plate 26 connected to this via a four-bar link mechanism consisting of shafts 23, 24, and 25, and a push-down foot 8 in contact with this are configured to rotate around a shaft 9. ing.

On the other hand, the shaft 11b of the eccentric cam 11 is connected to a one-way clutch reducing device 2 fixed to the outside of the sewing machine body 1.
7 output shaft (not shown). A pulley 28 is fixed to the input shaft 27a of the one-way clutch reducing device 27, and a pulley 3 is fixed to the shaft 30a of the motor 30 via a V-belt 29.
1 rotation is input. 3
Reference numeral 2 denotes a lever for operating the one-way clutch reducing device 27, which is connected to a pedal 34 via a chain 33, and is configured such that when the pedal 34 is depressed, the one-way clutch reducing device 27 is operated.

The operation of the presser foot mechanism of the conventional sewing machine configured as described above is such that when the pedal 34 is depressed, the chain 3
3, the lever 32 of the one-way clutch reducing device 27 is rotated, and as a result the eccentric cam 11 is rotated by 180 degrees.
Rotate it. When the roller 11a is released by the rotation of the eccentric cam 11, the levers 12, 13 and the shaft 1
The link mechanisms 4 and 15 move to the left in the figure under the bias of the spring 16, and rotate the shaft 19 clockwise via the lever 17.

Lever 20 and lever 2 fixed to shaft 19
1, 22, and shafts 23, 24, and 25, the push-down plate 26 is raised, and the push-down foot 8 in contact with it is rotated around the shaft 9 by the spring 10, lowering the presser foot 4 and moving the cloth 5 to the throat plate. 3 to complete the presser operation.

In the conventional cloth presser mechanism with such a configuration, the presser foot 4 moves intermittently up and down, so it is difficult to determine the sewing position of the workpiece. The disadvantages are that the operation is troublesome as the stitches must be moved up and down, and it takes time to determine the sewing position.

[Summary of the idea]

This device controls the height of the presser foot in proportion to the amount of pedal depression, stops lowering the presser foot just before pressing the fabric, positions the fabric, and then presses the pedal further. The purpose of the present invention is to propose a cloth presser mechanism for a sewing machine that can securely press the cloth at a desired position.

[Example of idea]

FIG. 2 is an overall front view showing the sewing machine presser mechanism according to this invention, and the same parts as those of the conventional example described above are given the same reference numerals and their explanations will be omitted.

34 is a pedal for controlling the height of the presser foot 4 that presses the cloth 5; 35 is a pressure reducing valve that is operated by a pin 35a connected to the pedal 34 in accordance with the amount of depression of the pedal 34.

A secondary pressure gauge 36 is connected midway through an air circuit 36a branched from the air circuit 37, and the tip of the air circuit 38 communicates with the outlet on the pressure reduction side of the pressure reduction valve 35. Pressure air supplied from a pressure tank (not shown) in the direction of arrow g is divided into two parts,
One side communicates with the inlet of the pressure reducing valve 35, and the other side communicates with the solenoid valve 39 through an air circuit 40. It communicates with the air circuit 37.

Reference numeral 41 denotes a limit switch, which is installed so as to be activated when the pedal 34 is fully depressed. The contact of the limit switch 41 is connected to the coil 39a of the solenoid valve 39 via the latch circuit 41a, and the contact
The coil 39a is activated by turning ON.

The sewing machine body 1 includes a cylinder 42, a return spring 43,
A drive mechanism S consisting of a piston 44 is provided, and a cylinder rod 45 is integrally connected to the push-down plate 26. The upper end of the cylinder 42 is attached to the sewing machine body 1 by a shaft 47.

The lower air supply port of the cylinder 42 is connected to the air circuit 37.
It is connected to the tip of.

Next, the operation of the embodiment configured as above will be explained.

Now, FIG. 2 shows a state in which the presser foot 4 is raised. At this time, the air circuits 37 and 38 are at atmospheric pressure, and the piston 44 is located downward by the return spring 43, overcoming the force of the spring 10, pushing down the foot 8,
The presser foot 4 is raised via the shaft 9.

First, when the pedal 34 is depressed, the pressure reducing valve 35 is activated via the pin 35a, and the air pressure in the secondary pressure gauge 36 and the air circuit 38 increases in proportion to the amount by which the pedal 34 is depressed. Air pressure passes through the air circuit 37 and is supplied to the pneumatic single-acting cylinder 42 .

The piston 44 moves upward while compressing the return spring 43 in the cylinder 42 by the supplied air pressure, and the supply pressure and the return spring 43 and spring 10
The cylinder rod 45 fixed to the cylinder 42 and the push-down plate 26 stop at a position proportional to the supply pressure generated by the amount of depression of the pedal 34.
Therefore, the presser foot 4 presses and fixes the cloth 5 against the throat plate 3 by means of the push-down foot 8, spring 10, and shaft 9 fixed to the feed plate 6 and the feed base 7. At this time, the limit switch 41 is operated to cut off the air circuit 38 that operated the solenoid valve 39 via the latch circuit 41a, connect the air circuit 40, and supply pressure to the air circuit 37. Even if the pedal 34 is released thereafter, the presser foot 4 continues to press and fix the cloth 5.

Then, when the sewing machine is started and the sewing process is completed, or when the pedal 34 is depressed again, the air circuits 37, 38, 40 are reset by the latch circuit 41a and return to the initial state.

[Effect of idea]

As described above, according to this invention, a mechanism is provided to control the height of the presser foot in proportion to the amount of pedal depression, so the presser foot is stopped just before pressing the cloth, the cloth is positioned, and the pedal is then pressed. It is possible to press the cloth securely by stepping on it, it is easy to position the object to be sewn, the stitching position is uniform, the quality is improved, and the stitcher does not have to use unnecessary positioning operations, which improves the work speed.

By operating the control means that controls the presser foot height in proportion to the amount of pedal depression and the drive mechanism that drives the presser foot mechanism using pressurized air, there is no need to use a link mechanism feedback control mechanism. It has many advantages such as being simple, low cost, and can be used as a process control that does not require much precision because it follows simple setting inputs.

[Brief explanation of the drawing]

FIG. 1 is an overall front view of the main parts of a sewing machine showing the presser mechanism of a conventional sewing machine, and FIG. 2 is an overall front view of the main parts of a sewing machine showing an embodiment of this invention. 3... Throat plate, 4... Presser foot, 5... Cloth, 34...
...pedal, P...pressure mechanism, S...drive mechanism,
Q...Control mechanism.

Claims (1)

[Scope of Claim for Utility Model Registration] A presser foot that is vertically movably supported on a feed base that is movable along a predetermined sewing shape, and that always receives an elastic force to press the workpiece against the upper surface of the bed; A drive mechanism is installed in the sewing machine frame and operates in a direction to press the presser foot against the upper surface of the bed by supplying air.The drive mechanism and pressure tank are electrically connected to each other through an air circuit and actuated by the operation of the sewing machine pedal. and a pressure reducing valve that is electrically connected to the solenoid valve through an air circuit and operates according to the amount of pedal depression to control the air pressure from the pressure tank. A presser foot mechanism for a sewing machine, characterized in that the height of the presser foot is controlled by controlling air pressure from a pressure tank.