JP3550798B2 - sewing machine - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a sewing machine that drives a sewing needle at a higher speed as the amount of movement of a sewing object per stitch is smaller.
[0002]
[Prior art]
Conventionally, in a sewing machine, a sewing needle is attached to the sewing machine such that a needle hole of the sewing needle penetrates in a front-rear direction of the sewing machine, and a needle thread of the sewing needle is passed through a lifting mechanism such as a balance or a slack removing spring. Is inserted through. On the other hand, the bobbin thread of the sewing machine is stored in a bobbin arranged at the center of the shuttle rotating in a certain direction. When the sewing needle rises after penetrating the work cloth, the upper thread forms a thread loop that spreads in the front-rear direction of the sewing machine near the needle hole, and the thread loop of the upper thread is moved by the hook point of the shuttle that has moved in the left and right direction. The upper thread and the lower thread are engaged, and are engaged.
[0003]
When performing embroidery, an embroidery frame moving device that moves the work cloth relative to the sewing needle that moves up and down, back and forth, and left and right is mounted on the sewing machine. When the sewing needle is positioned on the needle away from the workpiece cloth, only embroidery frame Attach the work cloth stitch is moved are formed one by one. In the sewing machine, the rotation speed of the sewing machine motor and the driving speed of the sewing needle are configured to be directly proportional, and the moving amount of the embroidery frame is determined for each stitch based on the feed data sequentially read from the ROM.
[0004]
For example, since the embroidery frame moving device for home use is a device used in a general home, it is required to be miniaturized. Since the embroidery frame is moved by a small and low-output motor, the moving amount indicated by the feed data is required. The larger the is, the longer the moving time required for the moving amount of the embroidery frame is required. Even if a high-output motor is used, if the amount of movement increases, the time required for moving the embroidery frame also becomes longer.
[0005]
Accordingly, in order to obtain the moving time of the embroidery frame, the sewing machine motor that continuously moves the sewing needle up and down is controlled at an instruction speed that is inversely proportional to the moving amount indicated by the feed data. That is, as shown in FIG. 6A, when the moving amount of the embroidery frame is large, the sewing machine motor rotates slowly. Conversely, when the moving amount indicated by the feed data is small, the moving time of the embroidery frame is short. Therefore, the instruction speed of the sewing machine motor rotates fast.
[0006]
[Problems to be solved by the invention]
However, when the movement amount indicated by the feed data is small, the instruction speed of the sewing machine motor is set to the maximum speed Vmax. Since the sewing machine motor and the sewing needle are driven at a high speed, the upper thread is pulled out at a high speed while being in contact with the sewing needle, the balance, the slack removing spring, etc., so that the twist of the upper thread is unraveled and the quality is deteriorated. Furthermore, if the sewing needle falls at almost the same position at high speed, the needle thread will loosen and the embroidery frame will vibrate. There was a problem that the hook point of the kettle spread and failed to catch the thread loop. In addition, it is troublesome to store in advance data for controlling the sewing machine at a low speed at a location where the sewing needle falls at almost the same position at such a high speed, and the data amount is increased. Was.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a sewing machine that can form stitches accurately even when a small workpiece is fed.
[0008]
[Means for Solving the Problems]
Sewing machine according to the first aspect of the present invention to achieve this object, when the moving amount per stitch is below the limit moving amount determined in advance, to release the high speed driving of the needle, the sewing machine Control means for controlling so as to set the minimum speed .
[0009]
In the sewing machine according to the present invention, it is determined that, among the plurality of pieces of feed data which are continuously read in advance from the storage means , the feed data having a movement amount per stitch equal to or less than a predetermined limit movement amount is continuous. And a control means for controlling so as to cancel the high-speed drive of the sewing needle when the first determination means determines that the feed data equal to or less than the limit movement amount is continuous . .
[0010]
Further, the sewing machine according to claim 3 , a second determination unit that determines that an accumulated movement amount obtained by accumulating a plurality of pieces of feed data that are continuously read from the storage unit in advance is equal to or less than a predetermined movement amount, And control means for controlling so as to cancel the high-speed drive of the sewing needle when the second determination means determines that the movement amount is equal to or less than the predetermined movement amount .
[0011]
[0012]
[0013]
[Action]
In the sewing machine according to the first aspect of the present invention having the above configuration, when the moving amount per stitch is equal to or less than a predetermined limit moving amount, the control means cancels the high-speed driving of the sewing needle , Set the minimum speed of the sewing machine .
[0014]
Further, in the sewing machine according to the second aspect, when the first determination means determines that the feed data whose movement amount per stitch is equal to or less than a predetermined limit movement amount is continuous, the control means performs the sewing. Control is performed to release the high-speed drive of the needle .
[0015]
Further, in the sewing machine according to the third aspect, when the second determination means determines that the accumulated movement amount obtained by accumulating the feed data is equal to or less than a predetermined movement amount , the control means controls the high speed of the sewing needle. Release the drive.
[0016]
[0017]
[0018]
【Example】
Hereinafter, an embodiment in which the present invention is embodied by a household sewing machine with an embroidery function will be described with reference to the drawings.
[0019]
As shown in FIG. 1, an embroidery frame driving device 5 equipped with an embroidery frame 3 for fixing a cloth on which embroidery is formed and a pulse motor for moving the embroidery frame 3 is mounted above the sewing machine bed 1. ing. The embroidery frame driving device 5 moves the embroidery frame 3 in orthogonal X and Y directions by using two low-power but small and inexpensive pulse motors. Also, a pillar 7 rising from the right end of the sewing machine bed 1, an arm 9 extending substantially parallel to the sewing machine bed 1 from an upper end of the pillar 7, and a head 11 provided at a tip of the arm 9. Sewing machine frame 17 is formed.
[0020]
The head 11 is provided with a start / stop switch 15 for controlling start and stop of the sewing machine, and a sewing needle 13 for forming embroidery is arranged under the head 11 so as to move up and down. . A needle plate 1a is disposed on the upper surface of the sewing machine bed 1 below the sewing needle 13, and a through hole is formed in the needle plate 1a through which the sewing needle 13 that moves up and down can pass. A horizontal shuttle that rotates in one direction is disposed below the needle plate 1a, and a bobbin in the center thereof stores a bobbin thread. The point of the horizontal hook is configured so that the needle thread of the upper thread expanding in the front-rear direction is captured by the needle hole of the sewing needle 13 so that the upper thread and the lower thread are engaged. The upper thread of the sewing machine is inserted into the needle hole of the sewing needle 13 through a lifting mechanism such as a balance or a slack removing spring (not shown) as in the related art.
[0021]
As shown in FIG. 2, the main circuit configuration includes a CPU 20 for processing a program command, a ROM 22 for storing a program, a ROM 24 for storing feed data, a RAM 26 for reading and writing data, and an upper axis. Needle position detection circuit 28 for detecting the position of sewing needle 13 from a timing shutter (not shown), motor control circuit 30, sewing machine motor 32 for rotating the upper shaft of sewing machine, embroidery frame drive circuit 34, and embroidery frame X An X pulse motor 36 for driving the embroidery frame 3 in the Y direction and a Y pulse motor 38 for driving the embroidery frame 3 in the Y direction. As shown in FIG. 5, the RAM 26 is provided with memories 26a to 26c used for controlling the sewing machine motor 32. As shown in FIG. 4, the feed data stored in the ROM 24 is configured to indicate one stitch by a set of two data indicating the lengths in two orthogonal directions.
[0022]
Next, a case of forming a stitch in a range Q (limit movement amount = longer than 0.3 mm) in FIG. 6B will be described.
[0023]
When it is confirmed by the needle position detecting circuit 28 that the sewing needle 13 is below the needle located below the needle plate 1, a predetermined number of feed data is read from the ROM 24 to the RAM 26 prior to sewing. Then, the CPU 20 specifies the speed of the sewing machine motor 32 in relation to the larger one of the feed data in the X direction and the Y direction. Specifically, when the distance indicated by the feed data is large, the moving amount of the embroidery frame 3 is large, and a long moving time is required, and the time when the embroidery frame 3 can be moved on the needle must be increased. Therefore, the instruction speed of the sewing machine motor 32 is set to a low speed. Conversely, when the distance indicated by the feed data is small, the moving time of the embroidery frame 3 is reduced, and the instruction speed of the sewing machine motor 32 is set to a high speed.
[0024]
Then, even if the embroidery frame 3 is moved by the needle position detection circuit 28, when the needle position (height) at which the sewing needle 13 and the embroidery frame 3 do not come into contact with each other, the X pulse motor 36 is connected to the embroidery frame drive circuit 34 via the embroidery frame drive circuit 34. by the Y pulse motor 38 is driven, it is moved a distance which is the embroidery frame 3 based on the feed data.
[0025]
In the range Q described above, if the length per stitch is short, the sewing needle 13 moves up and down at a high speed, but a short stitch less than the limit movement amount (= 0.3 mm) of the range P is formed. In this case, the above-described high-speed control is automatically released. Next, the sewing in which such a short stitch is formed will be described with reference to the stop sewing executed at the end of the embroidery pattern. The stop sewing is a sewing method for forming short stitches continuously at substantially the same position to prevent fraying of the embroidery pattern. As shown in FIG. 4, the feed data of the stop stitch is data of an address after the 95th end of the sewing stop of the embroidery pattern. Note that the flowchart shown in FIG. 3 is executed by the CPU 20 when the hand position detection circuit 28 determines that the hand is below the hand (timing t1: characters of timing hereinafter are omitted). Although the flowchart shown in FIG. 3 is executed in the range Q described above, the description is omitted.
[0026]
First, the memories 26a to 26c of the RAM 26 are initialized (S1: a = 0, b = 0), and the number of times of writing b from the ROM 24 to the memory 26c is incremented. The data is written into the first area of the memory 26c from the address No. (S2: b = 1). Then, it is determined that the larger movement amount (= 1) of the X-direction feed data (= 0.3 ) and the Y-direction feed data (= 1) is not less than the limit movement amount (= 0.3) ( (S3: No), the memory 26a is initialized (S5: a = 0).
[0027]
Next, it is determined that the maximum number of pieces of feed data that can be stored in the memory 26c has not been written in advance before sewing (S6: No, b <5). One set of address data is written to the second area of the memory 26c (S2: b = 2). Similarly, it is determined that the larger movement amount (= 1) of the sending data is not smaller than the limit movement amount (S3: No), the memory 26a is initialized (S5: a = 0), and It is determined that the writing has not been completed (S6: No).
[0028]
Next, the number of times of writing b is incremented, and a set of send data at the next 95th address is written to the third area of the memory 26c (S2: b = 3). It is determined that the larger movement amount (= 0.3) of the set of feed data is equal to or less than the limit movement amount (S3: Yes), and the number a of times below the limit is incremented (S4: a = 1). Subsequently, it is determined that the transmission data has not been read (S6: No), the number of times of writing b is incremented, and one set of transmission data at the next 96th address is written in the fourth area of the memory 26c. (S2: b = 4). Then, the amount of movement of the larger one of the feed data (= 0.3) is determined to be equal to or less than the limit moving amount (S3: Yes), the following number a is incremented limit (S 4: a = 2). Next, it is determined that the five feed data have not been read before the sewing (S6: No).
[0029]
Similarly, the number of times of writing b is incremented, and a set of sending data at the next 97th address is written to the fifth area of the memory 26c (S2: b = 5). Then, it is determined that the larger movement amount (= 0.3) of the set of feed data is equal to or less than the limit movement amount (S3: Yes), and the number a of times below the limit is incremented (S4: a). = 3). Subsequently, it is determined that the predetermined number of feed data has been read (S6: Yes, c = 5), and the number a of times below the limit has exceeded the threshold value (= 3) (S7: Yes). 32 is set to the minimum speed Vmin (S8 : t1 ), and the rotation speed of the sewing machine motor 32 starts to decrease. Following the above-described processing, a stitch is formed based on the feed data of the 92nd address (t2). In particular, the processing of (S7) functions as a first determination unit of the second aspect.
[0030]
In the subsequent stitch formation, the number a below the limit is equal to or more than the threshold value (= 3). Therefore, the instruction speed to the sewing machine motor 32 is set continuously to the minimum speed Vmin, and the rotation speed of the sewing machine motor 32 becomes Decelerate sequentially (after t1). The sewing machine motor 32 is decelerated to the minimum speed Vmin (t5), and the stop sewing of the 95th address and thereafter is executed (t7 and thereafter).
[0031]
Therefore, even when the workpiece cloth is moved below the limit travel distance, since the high-speed control based on the feed data below the limit travel distance is released, the twist of the thread and the twist of the thread are released. And the stitch formation failure due to the vibration of the embroidery frame 3 can be prevented. In the above-described embodiment, the control of the high speed of the sewing machine is released based on the feed data stored in the ROM 24 in advance, and no new data is stored in the storage device such as the ROM 24. Accordingly, it is possible to reduce the trouble of inputting new data for each embroidery pattern or for each portion having a small moving amount, and to prevent an increase in stored data.
[0032]
In the above-described embodiment, the sewing needle 13 is driven up and down at a speed (for example, the minimum speed Vmin) lower than the speed based on the feed data equal to or less than the limit movement amount (for example, the maximum speed Vmax). The stitches can be reliably formed even with the following movement amount. Further, in the above-described embodiment, the feed data is pre-read prior to the sewing, and a time for actually reducing the rotation speed of the sewing machine motor 32 is obtained. In the above-described embodiment, a high-quality sewn product that is resistant to fraying can be produced because important stop stitches can be reliably formed in order to maintain the formed stitches on the work cloth.
[0033]
In the above-described embodiment, the description has been given of the lock stitching. However, the same processing may be performed on a portion where the movement amount of the work cloth is equal to or less than the limit movement amount regardless of the lock stitch. In the above-described embodiment, the case where the sewing is completed has been described. However, the same processing may be performed for a portion where the movement amount of the work cloth is equal to or less than the limit movement amount regardless of the completion time. In the above-described embodiment, at a position where the feed data equal to or less than the limit movement amount is continuous, that is, at a position where the unraveling of the thread and the failure of the formation of the stitch are likely to occur, the failure of the unraveling of the thread and the failure of the formation of the stitch are determined. It is preventing. Also, the number of continuous feed data that is equal to or less than the limit movement amount as a criterion for canceling the high-speed drive does not need to be three as in the above-described embodiment. What is necessary is just to set according to a kind, cloth quality, thread quality, the kind of the embroidery frame 3, and the like.
[0034]
Further, in the above-described embodiment, even if the feed data equal to or less than the limit movement amount continues twice or less, the failure of the formation of the seam due to the loosening of the thread, the loosening of the upper thread, and the vibration of the embroidery frame. In this sewing machine, the sewing speed is reduced as much as possible and the driving speed of the sewing needle 13 is increased as high as possible to perform sewing quickly. However, if there is at least one feed data that is equal to or less than the limit movement amount, a sewing machine that untwists the upper thread and fails to form a stitch due to the unwinding of the upper thread and the vibration of the embroidery frame 3 may occur. If so, the threshold value of S7 may be set to “1 or more”.
[0035]
In the above-described embodiment, when the number of continuous feed data equal to or less than the limit movement amount is equal to or greater than the threshold, the high-speed driving based on the feed data is canceled, but the distance indicated by the continuous feed data is accumulated. If the accumulated value is equal to or less than a predetermined value (this determination functions as the second determination means in claim 3) , the high-speed driving may be similarly released.
[0036]
Then, according to the above-described embodiment, since the high-speed driving of the sewing needle 13 is released and the minimum speed Vmin of the sewing machine is set, the speed is reduced most quickly, and the stitch can be reliably formed. . However, the high-speed driving of the sewing needle 13 may be canceled so as to set a speed of 50% or 10% of the speed obtained by the calculation based on the feed data. Further, the degree of deceleration does not need to be uniform as in the above-described embodiment, but may be set in multiple steps as long as a seam can be formed.
[0037]
【The invention's effect】
As described above, according to the sewing machine of the first aspect of the present invention, the smaller the amount of movement of the sewing object per stitch, the higher the speed at which the sewing needle is driven. When the moving distance is less than the determined limit, the sewing needle is controlled to release the high-speed drive and set the minimum speed of the sewing machine. it can be.
[0038]
Further, according to the sewing machine of the present invention, when a plurality of feed data are continuously read in advance from the storage means, and when it is determined by the first determination means that the feed data equal to or less than the limit movement amount is continuous, the control is performed. The means controls to release the high-speed drive of the sewing needle.Before the stitch is formed by the feed data less than the limit movement amount, the unwinding of the thread and the failure of stitch formation can be anticipated. Can be prevented .
[0039]
Further, according to the sewing machine of the third aspect , when the second determining means determines that the cumulative moving amount obtained by accumulating the continuous feed data is equal to or less than the predetermined moving amount , the control means controls the sewing needle. of Runode controls to release the high speed driving, the likely location of the failure of unwinding and stitch formation of twisting of the thread, it is possible to prevent failure of the undone and stitch formation of twisting the yarns in advance it can.
[0040]
[0041]
[Brief description of the drawings]
FIG. 1 is an external view of a sewing machine according to an embodiment of the present invention.
FIG. 2 is a block diagram of an electric circuit according to the present embodiment.
FIG. 3 is a flowchart of control according to the embodiment.
FIG. 4 is an explanatory diagram of feed data of the sewing machine according to the present embodiment.
FIG. 5 is an explanatory diagram of a RAM of the sewing machine according to the present embodiment.
FIG. 6A is a graph showing a relationship between a motor instruction speed and feed data in a conventional sewing machine. FIG. 6B is a graph showing the relationship between the motor instruction speed and the feed data in the sewing machine according to the present embodiment.
FIG. 7 is a timing chart of the sewing machine according to the present embodiment.
[Explanation of symbols]
20 CPU
24 ROM
26 RAM
30 Motor control circuit

Claims (3)

In a sewing machine that drives a sewing needle at a higher speed as a moving amount of a sewing object per stitch is smaller,
When the movement amount per one stitch is equal to or less than a predetermined limit movement amount, a control means for canceling high-speed driving of the sewing needle and setting a minimum speed of the sewing machine is provided. A sewing machine characterized by the following. At the time of sewing, the sewing machine reads feed data relating to the movement amount from the storage means, and drives the sewing needle at a higher speed as the movement amount per stitch of the sewing object is smaller.
A first determination unit that determines that, among the plurality of pieces of the feed data that are sequentially read in advance from the storage unit, feed data having a movement amount per stitch equal to or less than a predetermined limit movement amount is continuous; ,
A sewing machine comprising: a controller configured to release high-speed driving of the sewing needle when the first determining unit determines that feed data equal to or less than the limit movement amount is continuous . At the time of sewing, the sewing machine reads feed data relating to the movement amount from the storage means, and drives the sewing needle at a higher speed as the movement amount per stitch of the sewing object is smaller.
A second determination unit that determines that an accumulated movement amount obtained by accumulating the plurality of pieces of the feed data that are continuously read in advance from the storage unit is equal to or less than a predetermined movement amount;
Wherein when it is determined to be less than the predetermined amount of movement by the second determination means, a sewing machine, characterized in Rukoto and control means for controlling so as to cancel the high-speed driving of the sewing needle.

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