JPH0341664Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is a needle mounting device of a sewing machine, and in particular, a needle mounting device of a sewing machine, which controls the position so that the needle bar is stopped at approximately the needle top dead center position when replacing the needle during the sewing process. In addition, the present invention relates to a position regulating device for a needle mounting mechanism of a sewing machine that enables easy needle replacement with one touch.

[Prior art]

Generally, it is necessary to change the sewing machine needle frequently during sewing work. This is useful if the sewing machine needle breaks due to the impact force when the needle moves up and down at high speed and penetrates the fabric, or if the material or thickness of the fabric is different, you can select the number type you need from the storage box. and must be worn.

Currently, these operations require a relatively long time and have considerable problems, such as having to cancel the series of operations each time. To solve this problem, there is a sewing machine needle mounting device as shown in FIG. In the figure, 1 is an upper shaft rotated by the driving source of the sewing machine, 2 is a counterweight connected to the upper shaft 1, and 3 is a crank rod that swings as the counterweight rotates. A needle bar 7a of a needle mounting mechanism 7 of the sewing machine is slidably moved up and down on a needle bar upper metal 5 and a needle bar lower metal 6 fixed to the machine frame of the sewing machine via a retainer 4. Further, the needle attachment mechanism 7 is disclosed in Utility Model Application No. 13497/1983 filed by the same applicant as this invention. That is, FIG. 4 shows the needle detached state (a state in which the needle comes out) indicated by the two-dot chain line from the needle attached state.
When the upper end of the bar member 7b loosely fitted into the hollow part of the needle bar 7a is pressed against the elastic force of the first elastic spring 7c,
The chuck means 7d screwed onto the rod member 7b is the needle bar 7.
The needle is moved from the locking portion 7f of the holder 7e screwed onto the lower end of the needle a, and the needle is removed from the state shown by the two-dot chain line, and the needle is removed and replaced. Next, when the upper end of the rod member 7b is not pressed, the rod member 7b is moved upward by the elastic force of the first elastic spring 7c, and the sleeve member 7h is pressed downward by the elastic force of the second elastic spring 7g. The tapered portion of the sleeve member 7h engages with the tapered portion of the chuck means 7d to fix the needle.

Now, when I need to change the needle during sewing work, I step on the sewing machine pedal and stop the sewing machine at the needle top dead center position. Next, when the operator turns on the knob switch (push button switch) 8 attached to the sewing machine arm, the solenoid valve drive circuit 9 is activated.
0 is activated and releases that valve.

Therefore, compressed air is supplied from the air supply source 11 to the air cylinder 12 via the electromagnetic valve 10, and the plunger 12a of the air cylinder 12 presses the rod member 7b that is loosely fitted to the needle bar 7a. Accordingly, the chuck means 7b is released downward from the holder 7e at the lower end of the needle bar 7a, and the needle 13 is removed.

Next, select the needle of the required number from the storage box and insert it into the chuck means 7d from below, and then turn off the needle switch 8. Since the compressed air is cut off, the plunger 12 of the air cylinder 12
a returns to its original state. Therefore, since the rod member 7b moves upward and returns to its original state, the chuck means 7d securely fixes the needle 13. Then, the sewing machine is put into operation.

[Problem that the invention attempts to solve]

However, in the conventional sewing machine needle mounting device described above, when the sewing machine is stopped, the needle 13 passes through the space between the needle plate and the cloth or the needle 13 from the top dead center position to the bottom dead center position. Since the sewing machine will stop at any position in between, the operator turns the sewing machine's handwheel by hand until it is at the appropriate position (e.g. approximately needle top dead center), turns on knob switch 8, and then sets the needle. 13 is removed from the chuck means 7d. Therefore, changing the needle requires a relatively long time, which poses a problem in terms of work efficiency. Also,
The sewing machine is designed to stop at the top dead center position of the thread take-up, and since the top dead center position of the needle is offset by about 30° from the top dead center position of the thread take-up, the needle bar 7a is at approximately the top dead center position. There is a small possibility that the needle bar 7a will stop at that position, and the needle bar 7a may move, and there is a risk that the worker's hand touching the needle will be pricked by the needle in order to remove the needle.

[Means for solving problems]

In order to solve the above-mentioned problems, this invention uses an upper shaft that is rotated by the sewing machine's drive source and a crank rod that is fixed to a counterweight linked to the upper shaft to move the needle up and down through the needle bar holder. a needle chuck means having a needle attached to the lower end of a bar member which loosely fits into the hollow part of the needle bar and is supported by a spring on the needle bar; and a needle chuck means which rotates in synchronization with the upper shaft. A needle position detection means detects the needle bar top dead center, a knob switch outputs a signal to the control means when replacing the needle, and the needle bar top dead center position is determined based on the operation signal of the knob switch, and the needle bar top dead center position is adjusted to the needle bar top dead center position. If there is no sewing machine, the sewing machine is provided with a control means for controlling the sewing machine to rotate to the needle bar top dead center position and then stopped, and a rod member driving means for pressing the upper end of the rod member based on an output signal of the control means, It is characterized in that the needle chuck means connected to the lower end of the member is configured to be released relative to the needle bar.

[Effect]

In this invention, a needle position detecting means is provided on the upper shaft of the sewing machine, and after the needle bar stops at approximately the needle bar top dead center position, the bar member driving means is activated to enable the needle to be replaced.
Work efficiency and safety are improved.

〔Example〕

FIG. 1 shows an embodiment of this invention, in which the same parts as in the prior art described above are denoted by the same reference numerals and redundant explanation will be omitted. In the figure, reference numeral 14 denotes needle position detection means for detecting the top dead center position of the needle bar mounted on the upper shaft of the sewing machine.

In general, this type of needle position detection means is an optical type or a magnetic induction type in which a light-shielding plate equipped with a slit or reflection plate facing a photoreflector having a light emitting element and a light receiving element is rotated in synchronization with an upper shaft. There is something.

Further, 15 is a CPU or a hardware circuit, 16 is a controller, and the rest is the same as the conventional one.

Next, the operation will be explained based on the flowchart shown in FIG.

When the sewing machine is stopped during a series of sewing operations that require replacing the needle 13, and then the knob switch 8 is turned on, the CPU or hardware circuit 15 detects whether the needle position detection means 14 is at the top dead center position of the needle bar. judge,
If it is at the top dead center position, the CPU or hardware circuit 15
The solenoid valve 1 is activated via the solenoid valve drive circuit 9 in accordance with the command.
0 turns on. If it is not at the top dead center position
The CPU or hardware circuit 15 instructs the controller 16 to rotate the sewing machine, and if the needle is at the top dead center position, the sewing machine stops in response to a command from the CPU or hardware circuit 15. Solenoid valve 10 is turned on. Then, the rod member driving means 10, 11, 12 are activated,
Since the rod member 7b is pressed, the needle chuck means 7d
is released and the needle chuck is released. Replace the needle in this condition. Next, when the knob switch 8 is turned off, the rod member driving means 10, 1 is activated via the control means.
Since the electromagnetic valves 10 and 12 are closed, the needle 13 is fixed to the needle chuck means 7d, the sewing machine starts operating, and the series of sewing operations is continued. Note that the rod member driving means 10, 11, 12 may be an actuator such as an electromagnetic solenoid or a motor.

[Effect of idea]

As explained above, this device is equipped with a needle position detection means on the upper shaft of the sewing machine, and when the needle bar stops at approximately the top dead center, the bar member driving means is activated, allowing the needle to be replaced. The needle can be easily replaced during sewing work, improving work efficiency, and the danger of the worker's hand being stabbed by the movement of the needle is eliminated, which has advantages such as improved safety.

[Brief explanation of the drawing]

Fig. 1 is a partial perspective view including a block diagram of this invention, Fig. 2 is a flowchart of Fig. 1, Fig. 3 is a perspective view including a conventional block diagram, and Fig. 4 shows the needle bar in Fig. 3. This is a longitudinal section. 1...Upper shaft, 7a...Needle bar, 7b...Bar member,
7d...chuck means, 7e...holding body, 8...
Knob switch, 13... Needle, 14... Needle position detection means, 15... Control means, 16... Controller, 10, 11, 12... Rod member driving means.

Claims (1)

[Scope of Claim for Utility Model Registration] A sewing machine equipped with an upper shaft that is rotated by a driving source of the sewing machine, and a needle bar that is moved up and down via a needle bar holder by a crank rod fixed to a counterweight linked to the upper shaft. a needle chuck means having a needle attached to the lower end of a bar member that loosely fits into the hollow portion of the needle bar and is supported by a spring on the needle bar; and a needle chuck means that rotates in synchronization with the upper shaft to detect the top dead center of the needle bar. a needle position detection means for detecting the needle position; a knob switch that outputs a signal to the control means when replacing the needle; and a knob switch that determines the needle bar top dead center position based on the operating signal of the knob switch, and if the needle bar top dead center position is not at the needle bar top dead center position, the sewing machine is moved to the needle bar position. A needle connected to a lower end of the rod member, comprising a control means for controlling the needle to rotate to the top dead center position and stop, and a rod member driving means for pressing the upper end of the rod member based on an output signal of the control means. 1. A position regulating device for a needle mounting mechanism of a sewing machine, characterized in that a chuck means is configured to be released from a needle bar.