JPH0741112B2 - Sewing machine lifting device - Google Patents

Description

The present invention relates to a presser foot lifting device for a sewing machine, and more particularly to a presser foot lifting device for a cycle stitch sewing machine such as a bartacking stitch sewing machine. .

(Prior Art) Conventionally, as a device of this type, a technique shown in the specification and drawings of Japanese Patent Publication No. 52-29212 is known. That is, the power of the sewing machine drive motor is used by using the power assist mechanism to drive the presser foot actuation cam, so that the presser foot can be lifted against the presser foot pressure with a light operating force. The operability of is improved.

(Problems to be Solved by the Invention) In the above-mentioned conventional technique, the operation of the presser is performed via the driving member that is constantly rotating. Generally, in sewing work,
Even when the sewing machine is stopped, the work clamp needs to be in a state in which it can be operated immediately when checking the holding state of the cloth.

Therefore, in the above technique, the sewing machine motor, which is the drive source of the presser drive member, is constantly rotated, and the drive of the main shaft of the sewing machine main body and the drive of the presser are separated by the clutch. These configurations have become complicated and large, and various inconveniences have been observed.

Also, in recent years, the use of a DC motor has become widespread for energy saving, and a method is adopted in which the motor is stopped when not sewing and the sewing machine is rotated at the same time when the sewing machine is started. In such a case, it is impossible for the above-mentioned conventional device to achieve its purpose.

In the present invention, the presser foot can be easily moved up and down independently of the sewing machine drive motor to eliminate the inconveniences found in the conventional apparatus.

[Structure of Invention]

(Means for Solving Problems) In order to solve the above problems, the present invention takes the following means. That is, a presser foot attached to a cloth presser arm fixed on a sewing machine bed so as to be vertically movable, a presser arm rotatably attached to the cloth presser arm and having one end fitted to the presser foot, and the presser foot. A presser spring that is disposed between the arm and the presser arm and constantly biases the presser arm so that the presser moves downward,
A small reduction motor attached to the sewing machine arm, a pinion gear provided on the reduction shaft of the small reduction motor, a rack that is vertically movably supported by the sewing machine arm and meshes with the pinion gear, and is attached to the rack. A presser lifting plate that presses the presser arm by the downward movement of the rack so that the presser moves upward against the urging force of the presser spring, and releases the pressing of the presser arm by the upward movement of the rack, And a control device for controlling the energizing direction of the small reduction motor so that the presser moves up or down based on an on / off signal of the presser lift switch.

(Function) When the work clamp operating switch is turned on by operating the foot pedal or manual button, the sub motor starts and the
The work clamp lifting plate rises due to the operation of the pinion. This lowers the presser foot of the sewing machine. When the presser foot operation switch is turned off, the sub-motor reverses to operate the rack downward and raise the presser foot of the sewing machine.

Next, turn on the start switch while turning on the work clamp operation switch.
When set to, the sub motor is activated to lower the work clamp, and subsequently the drive solenoid of the sewing machine operates to activate the sewing machine. When the feed cam rotates and one cycle of sewing is completed, the sub motor is activated and the work clamp rises.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. In the figure, 1 is a sewing machine arm, 2 is a bed, 3 is a needle bar, 4 is a presser foot, 5 is a presser foot arm, 6 is a lower presser foot, 9 is a presser arm, 11
Is a presser spring, 12 is a small reduction motor (hereinafter referred to as a sub motor), 15 is a rack, and 16 is each member of the presser lifting plate.

As seen in FIG. 3, the sub motor 12 is attached to the back side portion of the sewing machine arm 1. The pinion gear 13 provided at the tip of the reduction shaft 13a meshes with the blade portion 15a of the rack 15 pivotally supported by the arm 1. As is apparent from FIGS. 1 and 2, this rack 15 has a presser lifting plate 16 at its lower end.
Is fixed, and a stop washer 17 is fitted on the upper end and fixed by a nut 18. In addition, on the sewing machine bed 2,
The presser foot arm 5 is fixed by the screw 7 via the feed rod 20.

A presser foot 4 is attached to the cloth pressing arm 5 on the needle bar 3 side so as to be vertically movable, and a presser arm 9 is loosely attached by a pin 10. One end thereof is fitted in the holding portion of the presser 4 and the other end is constantly urged counterclockwise by the presser spring 11.

Thus, the rack 15 is restricted from rotating in the circumferential direction by an appropriate rotation preventing means (not shown).

Now, when the work clamp operation switch is turned ON, the sub motor 12 is activated to rotate the worm wheel 14, and the pinion gear
13 rotates counterclockwise and the rack 15 moves upward (second
Figure). Accordingly, the presser foot lifting plate 16 rises and separates from the contact piece 9a of the presser arm 9. At this time, the presser arm 9 is rotated counterclockwise by the pressure of the presser spring 11 to press the presser 4 against the bed surface. At this time, the power supply to the motor is turned off by the control circuit at a certain set time, and the rack 15 is stopped at the upper limit. Next, press the work clamp operating switch
When turned off, the sub motor 12 is energized to rotate in the reverse direction, and the pinion 13 of the motor rotates clockwise to move the rack.
Drop 15 Therefore, the presser foot lifting plate 16 is attached to the presser arm 9
And presser foot 4 is raised. When the rack 15 stops to the lower limit with the stop washer 17, the sub motor 12
The energization is controlled so that it is turned off. When the drive switch is turned on while the work clamp operation switch is still in the ON state, the sewing machine operates while the work clamp 4 holds the cloth, and one cycle of sewing is performed.

When this sewing is completed, the sewing machine stops and the work clamp rises to complete the sewing.

Next, the control circuit of the device of the present invention will be described with reference to FIGS.

That is, when only the presser is vertically controlled, as shown in FIG.
The raising / lowering operation lowers or raises the presser by turning the presser lifting switch ON / OFF to rotate the motor 12 forward or backward by the drive switch of the sub motor.

When the sewing machine is driven to sew one cycle, it is controlled like the timing chart shown in FIG. That is,
Turn the work clamp lift switch ON, rotate the sub motor 12 forward, lower the work clamp 4, and at the same time operate the sewing machine drive switch.
When turned on, the clutch of the sewing machine comes off and the feed cam rotates one cycle. During this time, the work clamp lift switch signal is ON.
When the feed cam makes one rotation and the sewing machine stops in this state, an OFF signal is input to the work clamp lifting switch, and the sub motor drive switch inputs a reverse rotation signal. Accordingly, the presser foot 4 is lifted by this and the sewing is completed.

〔The invention's effect〕

According to the present invention, the presser arm is pressed and released by the upward movement and downward movement of the presser lifting plate to perform the downward movement by the pressing force of the pressing spring and the upward movement against the pressing force of the pressing spring. As a result, the presser foot lifting plate is operated by the small reduction motor via the engagement of the rack and the pinion gear, which simplifies the control of the small reduction motor by the control device and is linked to the operation and the operation switch of the sewing machine. The vertical movement of the presser can be realized.

By the way, in order to achieve the same object as the present invention, it is conceivable to operate the presser foot using a solenoid without using a motor. However, in the case of a bartacking sewing machine, the work clamp is raised when the sewing machine is stopped.
The presser foot is lowered during cycle sewing, and the presser foot is automatically raised when one cycle is completed. Therefore, when the solenoid is used, the solenoid must be energized even while the solenoid is stopped, which causes adverse effects such as temperature rise. There is also a method in which when the cloth is pressed with the force of the solenoid and the energization of the solenoid is turned off, the work clamp rises due to the spring action, but this makes it difficult to adjust the work pressure. And in the case of a solenoid, a fairly large and powerful one is required. However, in the case of the present invention, it suffices to energize the motor only when moving up and down, and since it is not necessary to energize during sewing, there are peculiar effects such as low power consumption, small size, and strong working force.

Since the vertical movement of the rack is directly connected as the upward and downward movements of the presser, the clutch mechanism (power assist) as in the prior art is not required, and there is a secondary effect that the cost is low.

[Brief description of drawings]

FIG. 1 is provided with a presser lifting device (partial cross section) of the present invention,
FIG. 2 is the same as FIG. 1 in which the presser is lowered in the front view of the sewing machine, and FIG.
B-C-D line sectional views, FIG. 4 and FIG. 5 are diagrams showing timing charts of the control circuit, respectively. 1 ... Sewing machine arm, 2 ... Sewing machine bed, 4 ... Presser foot, 5 ...
...... Presser foot arm, 9 ...... Presser arm, 11 ...... Presser spring, 12 ...... Small reduction motor, 13 ...... Pinion gear, 15 ...... Rack, 1
6 ...... Presser lifting plate

Claims (1)

[Claims] 1. A presser foot movably attached to a cloth presser arm fixed on a sewing machine bed, and a presser arm rotatably attached to the cloth presser arm and having one end fitted to the presser foot. A presser spring which is arranged between the cloth presser arm and the presser arm and always biases the presser arm so that the presser moves downward, a small reduction motor attached to the sewing machine arm, and the small reduction motor. Pinion gear provided on the reduction shaft, a rack that is supported by the sewing machine arm so as to be movable up and down, and meshes with the pinion gear, and a downward movement of the rack that is attached to the rack causes the pressing arm to press the pressing arm. Based on the ON / OFF signal of the presser lifting plate and the presser lifting plate that presses the pressing arm to move upward against the biasing force of the spring and releases the pressing of the pressing arm by the upward movement of the rack. The pressing Te sewing machine presser lifting device and a control device for controlling the current direction of the small deceleration motor to move upward or downward.