JPS5946627B2 - Sewing machine rotation speed storage device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention detects the rotational speed of the sewing machine for each seam formation of the sewing operation by performing a predetermined suturing action by an operator's operation of the sewing machine, and detects the rotational speed of the sewing machine. A sewing machine is provided in which the speed data is sequentially stored in a storage means such as a microcomputer as speed data each time the speed data changes, and the number of stitches until new data is stored, that is, the number of stitches, is stored in the storage means. This invention relates to a rotational speed storage device.

Conventionally, in a given suturing action, the number of stitches, that is, the number of stitches, is set in advance using a digital switch, etc., and stored as data in a microcomputer or other storage means, and the suturing action is reproduced based on that data. According to this, if the rotational speed of the sewing machine differs for each suturing action reproduced,
A disadvantage arises in that the lengths of the seam lines vary, making it impossible to always accurately reproduce the seam dimensions.

This is because as the rotational speed of the sewing machine increases, the momentum of the feed dog increases due to its inertia force, which increases the amount of material fed by -pitch. The presser foot, which is rebounding from the movement of the feed dog, is unable to follow the vertical movement of the feed dog due to the upward inertial force of the presser foot and presser rod caused by the rise of the feed dog, and as a result, the presser foot and the feed dog This is due to a phenomenon peculiar to the cloth feeding action of a sewing machine, in which the cloth feeding action in cooperation with the sewing machine is no longer carried out properly, and the amount of cloth feeding decreases. In consideration of these phenomena, the present invention detects the rotational speed of the sewing machine each time the sewing stitch is formed, as described above, and stores the rotational speed of the sewing machine as speed data every time the rotational speed changes. sequentially stored in a storage means,
By storing the number of stitches until new data is stored, that is, the number of stitches, in the storage means, each stored data can be stored until the number of stitches until the next data is read out. For example, if the output data of a microcomputer is stored in a register or the like and the sewing machine is driven based on that data, the number of stitches in the sewing operation described above and the rotational speed of the sewing machine when forming each stitch can be accurately determined. The present invention aims to reproduce the suturing action without the above-mentioned conventional drawbacks, reduce the storage capacity of the storage means, for example, the memory capacity of a microcomputer, and furthermore, it is possible to memorize the rotational speed during a long-time suturing action. The purpose of this is to obtain a storage device with the following characteristics.

Embodiments of the present invention will be described below with reference to the drawings.
The sewing machine 1 shown in the figure has a driving motor 4 which is driven by a forward depression operation of a pedal 3 disposed below a sewing machine table 2.
The pedal 3 is driven by a motor pulley 5, a belt 6, and a sewing machine 7. The rotation speed of the drive motor 4 increases or decreases in proportion to the amount of depression, that is, the rotation speed of the sewing machine increases or decreases, and when the pedal 3 is released, the drive motor 4 stops and the sewing machine 1 stops.

The sewing machine 7 includes, for example, a Hall IC, a permanent magnet, a light emitting diode, and a photo. A pulse generator 9 made of a transistor is arranged, and the pulse generator 9 generates a timing pulse each time the main shaft of the sewing machine rotates once, that is, each time one stitch is performed.

The sewing machine control section 8 and the sewing machine rotational speed storage section will now be explained with reference to the block diagram of FIG. A pedal sensor such as a proximity switch made of a Hall IC and a permanent magnet is connected to the sewing machine pedal 3 so as to output a variable signal in proportion to the amount of depression of the pedal 3; A voltage conversion circuit for outputting a voltage proportional to the variable signal, that is, proportional to the amount of depression of the pedal 3, is connected. The output voltage from this voltage conversion circuit is input to the sewing machine control circuit via a switching contact C controlled by command switches A and B, which will be described later, and the control circuit rotates the sewing machine according to the input voltage value. The drive motor 4 is controlled by the speed. In addition, the voltage output from the voltage conversion circuit is input to an analog memory (for example, an analog memory element EUW-AOC manufactured by Matsushita Electronic Components Co., Ltd.), a comparison circuit, and an A/D conversion circuit. The memory, comparison circuit, and A/D conversion circuit are operated in the order shown in the timing chart of FIG. 3 by a timing control signal outputted from the timing control circuit every time the timing pulse is generated. Each time a signal is input from the timing control circuit, the analog memory operates to temporarily hold the output voltage from the voltage conversion circuit until the next signal is input, and the comparison circuit receives a signal from the timing control circuit. Each time the voltage value in the analog memory is compared with the output voltage from the voltage conversion circuit, if there is a difference between the voltage values, a signal is output to the A/D conversion circuit. The A/D conversion circuit opens its gate according to the output signal from the comparison circuit and the output signal from the timing control circuit, inputs the output voltage from the voltage conversion circuit, and converts it into a digital signal corresponding to the voltage value. It's summery.

This A/D conversion circuit is connected to the input register of a microcomputer MC, which has functions such as a memory control circuit including a microprocessor, memory (RAM), and various input registers. The digital signal converted by the /D conversion circuit is held. The memory control circuit of the microcomputer MC receives an input request signal from the comparator circuit upon completion of the voltage value comparison operation, a timing control signal from the timing control circuit, and a command switch appropriately placed on the sewing machine table. The operation of switch A inputs a data storage command signal, the operation of command switch B inputs a data read command signal, and the operation of start switch S inputs a start signal. Each time the input request signal is input, the control circuit sequentially stores the digital signal held in the input register in the memory as rotational speed data, and uses a counter included in the microcomputer MC to read the signal from the timing control circuit. By counting the number of stitches until the digital signal is stored, that is, the number of stitches, is converted into a digital signal and stored in the memory as stitch count data.On the other hand, when a data read command signal is input In,
The first signal stored by inputting the start signal is read from the memory and held in the output register, and after the sewing machine is driven based on that signal as described later, the timing pulse generated from the pulse generator 9 is Based on this, each time a signal is input from the timing control circuit, the second signal is read out successively.

The output register of this microcomputer has a D/D converter that converts the digital signal held in the register into a voltage value corresponding to the digital value and outputs it.
A conversion circuit is connected, and its output voltage is input to the sewing machine control circuit through the switching contact C, and as described above, this control circuit drives the drive motor 4 at a rotational speed corresponding to the voltage value. It's becoming controlled.

The changeover contact C is controlled to be in the solid line position in FIG. 2 when the command switch A is activated, and to the two-dot chain line position when the command switch B is activated. Based on the stitch formation shown in FIG. 4, the manner in which the rotational speed and stitch number signals are stored in the memory shown in FIG. 5 and the reading operation thereof will be explained. In forming the stitches in FIG. 4, as shown in FIG. 6, the sewing machine 1 is rotated at low speed until the third stitch, that is, the third stitch, and at medium speed from the fourth stitch to the eighth stitch.
By rotating at a high speed from the 9th stitch to the 14th stitch, again at a medium speed from the 15th stitch to the 17th stitch, and then at a low speed from the 18th stitch to the 20th stitch and then stopping, a straight line consisting of 20 stitches is sewn. It forms the line of sight. The above memory has a capacity of 8 bits per word, and is designed to store 2 words as one data unit, with the first word containing the stitch count signal and the second word containing the rotation speed signal. Therefore, the number of stitches is stored in the memory at odd addresses, and the rotational speed signal is stored at even addresses. something is shown. First, when command switch A is operated, switching contact C is controlled to the solid line position in FIG. 2, and a data storage command signal is input to the memory control circuit.

In this state, if the operator depresses the pedal 3 appropriately and performs the stitch forming operation, the drive motor 4, that is, the sewing machine 1, is activated via the pedal sensor 1, voltage conversion circuit, switching contact C, and sewing machine control circuit. By sequentially controlling the rotational speed as described above, a straight seam line consisting of 20 stitches shown in FIG. 4 is formed.

When the first timing pulse is generated from the pulse generator 9 by driving the sewing machine 1, the timing control signal is first input from the timing control circuit to the comparison circuit, the comparison circuit is activated, and the signal is stored in the analog memory. The voltage value output from the voltage conversion circuit is compared with the voltage value output from the voltage conversion circuit. In this case, since the analog memory holds a signal corresponding to stopping the sewing machine when the command switch A is activated, that is, ``l'o'' as a voltage value, the sewing machine outputting from the voltage conversion circuit Since there is a difference between the voltage value corresponding to low speed rotation, the A/D
At the same time as the signal is output to the conversion circuit, the analog memory is reset by the signal from the timing control circuit to hold the voltage value output from the voltage conversion circuit. Then, the output voltage from the voltage conversion circuit is input to the A/D conversion circuit according to the signal from the comparison circuit and converted into a digital signal corresponding to the voltage value, that is, corresponding to the low speed rotation of the sewing machine. It is input and held in the input register of the computer-MC, and
In response to the input request signal output from the A/D conversion circuit in connection with the completion of the signal conversion, the memory control circuit stores the signal 30'' held in the input register at the second address of the memory, and at the same time stores the signal 30'' as the number of stitches. Store the needle signal も00'' in the first address.

Then, when the first sewing is finished and the next timing pulse is generated, the comparison circuit again compares the whistle pressure value held in the analog memory with the output voltage value from the voltage conversion circuit, as described above. In this case, the voltage value corresponding to the low speed rotation of the sewing machine is held in the analog memory as described above, and on the other hand, the voltage value corresponding to the low speed rotation is also output from the voltage conversion circuit. Since there is no difference in the values, no signal is output from the comparison circuit to the A/D conversion circuit, and therefore no input request signal is output from the A/D conversion circuit, the memory control circuit does not operate. In addition, even if a timing pulse occurs after the second stitch is completed, the voltage conversion circuit also outputs the voltage corresponding to low-speed rotation, so the A/D conversion circuit and memory control circuit operate in the same way as above. do not.

When a timing pulse is generated after the third stitch is completed, the voltage conversion circuit is outputting a voltage corresponding to medium speed rotation, so after the comparison operation by the comparison circuit, the A/D conversion circuit operates and The voltage value is converted into a digital signal ゜70'' corresponding to medium speed rotation, and the voltage value is held in the analog memory, and the memory control circuit converts the 4th word of the memory into the 4th word of the memory based on the input request signal from the A/D conversion circuit. The above signal ゜70'' is memorized and the number of stitches is 3.
The stitch signal ゜03'' is stored in the third word. Since the voltage corresponding to the above-mentioned medium speed rotation is continuously output from the voltage conversion circuit from the 4th stitch to the 8th stitch, the timing Even if a pulse occurs, the memory control circuit does not operate and no data is stored in the memory.However, if a timing pulse occurs after the completion of the 8th stitch, the voltage corresponding to high speed rotation is output from the lightning pressure conversion circuit. is output, so after the comparison operation by the comparison circuit, the A/D conversion circuit operates and converts the voltage value into a digital signal corresponding to high-speed rotation.
At the same time, the voltage value is held in the analog memory, and the memory control circuit converts the voltage value into the sixth word of the memory by the input request signal from the A/D conversion circuit.
Memorize O2 and set the 8th stitch signal to 0 as the number of stitches.
8'' is stored in the 5th word, and when a timing pulse is generated after the completion of the 14th stitch, a signal ゜70'' corresponding to medium speed rotation is stored in the 8th word and 1 as the number of stitches is stored in the 7th word.
The signal もObi for the 4th stitch is memorized, and when a timing pulse is generated after the completion of the 17th stitch, the signal ゜30'' corresponding to low speed rotation is stored in the 10th word, and the signal for the 17th stitch is stored in the 9th word as the number of stitches. Memorize ゞ11″. And the 20th
When the sewing machine is stopped after completing a stitch, the sewing machine stop signal ``00'' is stored in the 12th word, and the 20th stitch signal ``14'' is stored in the 11th word. Therefore, when the command switch B is operated, the switching contact C is controlled to the position indicated by the two-dot chain line in FIG. 2, and a data read command signal is input to the memory control circuit.

When the start switch S is activated in this state, the memory control circuit reads out the first rotational speed signal stored in the memory, that is, the second word "30", and holds it in the output register. The D/A conversion circuit converts it into a digital value, that is, a voltage value corresponding to low-speed rotation, and outputs it.The output voltage is input to the sewing machine control circuit through the contact C, and is input to the driving motor 4, that is, the sewing machine. 1 is driven at a low speed rotation.As a result of this driving, the memory control circuit counts timing control signals output from the timing control circuit in relation to timing pulses generated from the pulse generator 9.
When the counted number, that is, the number of stitches matches the number of stitches in the stitch number signal stored in the memory, a rotational speed signal related to the number of stitches is read out. That is, at 3 counts of the timing control signal, the fourth word signal is read out and the sewing machine is controlled from low speed rotation to medium speed rotation, and at 8 counts, the 6th word signal is read out and the sewing machine changes to medium speed rotation. The signal of the 8th word is read out at 14 counts, and the sewing machine changes from high speed rotation to medium speed rotation.
The signal of the 10th word is read at the count, and the sewing machine is controlled from medium speed rotation to low speed rotation, and when the count reaches 20, the signal of the 12th word is read. The sewing machine is stopped when the material is removed. As a result, the number of stitches, that is, the number of stitches and the pitch of each stitch are accurately reproduced, and the stitch line formed by the operator's pedal operation is ``accurately reproduced'' as it is. As described above, the present invention detects the rotational speed of the sewing machine each time a stitch is formed in the suturing operation, and stores the rotational speed sequentially in a storage means such as a microcomputer as speed data every time the rotational speed changes. In addition, since the number of stitches until new data is stored, that is, the number of stitches, is stored as data in the storage means, the microcomputer, for example, can By storing this in the output register, the number of stitches and the rotational speed of the sewing machine for each stitch formation in the above-mentioned suturing action can be reproduced, so the pitch of each stitch can be accurately reproduced. Therefore, the entire length of the seam line can be accurately reproduced, and the operator only has to perform the specified sewing operation while appropriately controlling the rotational speed of the sewing machine during the first sewing operation. In the suturing operation, the initial suturing action can be accurately reproduced simply by starting the sewing machine, which significantly reduces the burden on the operator's negative fingers and significantly improves the efficiency of the suturing action. In addition, since the data stored in the storage means can be kept to a minimum, the storage capacity can be reduced, and the suturing action can be reproduced for a long time, making it more economical and versatile. It has excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a front view of the sewing machine, Fig. 2 is a block diagram centered on the sewing machine's rotational speed detection circuit and a storage control circuit for the detected speed data, and Fig. 3 is a configuration of the storage control circuit shown in Fig. 2. Figure 4 is an explanatory diagram showing an example of stitch formation, Figure 5 is an explanatory diagram showing how data is stored in memory, and Figure 6 is the circuit speed of the sewing machine during the sewing shown in Figure 4. This is a timing chart showing changes in .

Claims (1)

[Claims] 1. A sewing machine that can be driven and stopped by controlling the rotational speed as appropriate by the operator, includes pulse generation means for generating timing pulses in synchronization with the driving of the sewing machine, and a means for detecting the rotational speed of the sewing machine. a detection means for outputting a voltage corresponding to the speed; a holding means for operating in relation to each timing pulse to temporarily hold the output voltage from the detection means until the next timing pulse occurs; a comparison means that performs a related operation every time a pulse is generated, compares the voltage value held in the holding means and the output voltage value from the detection means, and outputs an output if there is a difference between the voltage values;
a converting means for converting the output voltage from the detecting means into a digital signal corresponding to the voltage value according to the output from the comparing means; and a converting means for converting the output voltage from the detecting means into a digital signal by the converting means. A rotational speed storage device for a sewing machine, comprising a storage means for sequentially storing the signals and simultaneously storing the number of stitches until each signal is stored.