JPH07112090A - Feed device of sewing machine - Google Patents

Abstract

PURPOSE:To exactly generate a desired moving amount, and to allow the device to have a high resolution by constituting the device so that, in the case of making the next seam, and excitation state therefor is started from an excitation phase energized by the previous advance, and after switching to all the excitation phases is executed, the excitation state is switched in reverse and a feed dog is moved backward. CONSTITUTION:A feed dog 1 is moved to the forward and backward directions by a forward/backward feed pulse motor 2 and a link mechanism, and the forward/backward feed pulse motor 2 is controlled by an excitation controller 3a of a feed controller 3. Also, the forward/backward feed pulse motor 2 can execute eight kinds of excitation states, and when the excitation phase makes the round and the same excitation phase is energized again, the forward/ backward feed pulse motor 2 makes one rotation. Moreover, when the excitation state of the forward/backward feed pulse motor 2 is switched to the adjacent phase, a fact that the feed dog 1 moves in the forward and the backward directions by a set moving amount is set in advance. When the excitation state (a) is switched to the excitation state (b), the feed dog 1 moves by two folds of the set moving amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feeding device for a sewing machine which moves a feed dog by a pulse motor.

[0002]

2. Description of the Related Art Conventionally, such a sewing machine feed device is described in Japanese Patent Publication No. Hei 1-199114 by the present applicant, which is used for driving a sewing machine motor and a feed dog. And a pulse motor. Further, the feed device of the sewing machine is configured to directly drive and control the feed dog by a pulse motor, a link mechanism and the like.

The feed dog is constructed so that it moves forward from a predetermined movement start position until it reaches a desired movement amount, and retracts each time the movement is advanced. Therefore, when the same amount of movement is repeated, the specific excitation state of the pulse motor repeatedly acts,
The feed dog is configured to be advanced or retracted.

Further, in the control of the pulse motor, if the number of phases for switching the excitation phases is the same, the amount of movement of the feed dog is constant regardless of which excitation phase is switched to which excitation phase. It is assumed in advance. That is, in the pulse motor having four excitation phases a, b, c, d, the moving amount of the feed dog is changed depending on whether the excitation phase is changed from “a” to “b” or from “b” to “c”. It is assumed in advance that the amount of movement of the feed dog is the same when the excitation phase is switched from "a" to "c" and when the excitation phase is switched from "b" to "d". However, it is very difficult to manufacture a pulse motor so that each excitation phase produces a completely uniform magnetic action due to the displacement of the mounting position and the unevenness of the material. Therefore, even if the same amount of movement command is output, the movement amount of the feed dog increases or decreases depending on which excitation phase is switched to which excitation phase, and the desired movement amount and the actual movement amount are reduced. The amount of movement is slightly different.

Next, it will be described with reference to FIG. 4 that the stop position accuracy is generally poor in the one-phase excitation state of the pulse motor.

FIGS. 4 (a) to 4 (d) show respective relative positions of the field side and the rotor side in the one-phase excitation and the drive vector, which are in the lateral direction between (b) and (c). The vector is not generated and it becomes possible to stop at any position, and the stop position accuracy deteriorates.

On the other hand, FIGS. 4 (e) to 4 (g) show respective relative positions and drive vectors in the two-phase excitation. Only the position (f) can be stopped and the stop position accuracy is improved. .

As described above, since the accuracy of the stop position in the 1-phase excitation by the 1-2 phase excitation method is poor, the pulse motor is driven by the 2-2 phase excitation method as a direct drive device for the feed dog. It was

[0009]

However, if the excitation state is repeatedly switched to generate a movement amount deviating from the predetermined movement amount, there is a problem that a desired pattern or the like is deviated and embroidery is performed.

Further, when the pulse motor is driven by the 2-2 phase excitation method, there is a problem that the minimum resolution is reduced to 1/2 as compared with the case where the pulse motor is driven by the 1-2 phase excitation method.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a sewing machine feed device which accurately produces a desired movement amount and has high resolution. Especially.

[0012]

In order to achieve this object, the feed device of the sewing machine of the present invention advances the feed dog to create one stitch, and then advances the feed tooth to move the feed dog to the next position. When creating a seam, start the excitation state for forming the next stitch from the excitation phase excited in the previous advance,
In addition, after the switching to all the excitation phases is performed at least once, the excitation state is switched to the reverse direction to retract the feed dog.

According to a second aspect of the present invention, the sewing machine feed device advances the feed dog from the two-phase excitation state to create one stitch, and then advances the feed tooth to advance the next stitch. To create the next stitch, the excitation state for forming the next stitch is started from the excitation phase excited in the previous advance, and when the advance is completed in the two-phase excitation state, the two-phase excitation state is changed. It has a configuration in which the excitation state is switched in the opposite direction to retract the feed dog.

[0014]

In the feeder of the sewing machine according to the first aspect of the present invention having the above-mentioned structure, the feed dog is advanced to make one stitch, and then the feed tooth is advanced to the next step. When creating a stitch, the excitation state for forming the next stitch starts from the excitation phase excited in the previous advance, and after switching to all the excitation phases at least one order, Switch the excitation state in reverse and retract the feed dog.

In the sewing machine feed device according to a second aspect of the present invention, the feed dog is advanced from the two-phase excitation state in order to create one stitch, and then the feed tooth is advanced to move to the next stitch. When creating a stitch, the excitation state for forming the next stitch is started from the excitation phase excited in the previous advance, and when the advance is completed in the two-phase excitation state, the two-phase excitation state To reverse the excitation state and retract the feed dog.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The feed dog feed mechanism and the pulse motor have the same configurations as those in Japanese Examined Patent Publication No. 1-191414, and thus detailed description thereof will be omitted.

In the sewing machine having the sewing machine feeding device of the present invention, the feed dog 1 can be projected from the upper surface of the bed (not shown) and can be lowered into the bed. As shown in FIG. 1, the feed dog 1 is configured to be moved in the front-rear direction by a front-rear feed pulse motor 2 and a link mechanism. This cross feed pulse motor 2
Is configured to be controlled by the excitation controller 3a of the feed controller 3.

Further, in the forward / backward feed pulse motor 2, the excitation states a, ab, b, bc, c, cd, d, da.
It is configured such that eight kinds of excitation states can be performed. Further, when the excitation phases are sequentially excited and the same excitation phase is excited again, the forward / backward feed pulse motor 2 is configured to rotate once. It is assumed in advance that the feed dog 1 moves in the front-rear direction by the set movement amount s when the excitation state of the forward-backward feed pulse motor 2 is switched to the adjacent phase. When the excitation state is switched from the excitation state a to the excitation state b, the feed dog 1 is "2s" which is twice the set movement amount.
It is configured to move.

Further, the maximum moving amount of the feed dog 1 is 20 pulses, and the feed dog 1 is at the positions P1 to P2 in the front-back direction in the drawing.
It is configured so that it can be stopped at 1. Further, the feed dog 1 is configured to move up and down by the feed dog up-and-down moving device 4 in synchronization with the up-and-down movement of the sewing needle.

In the pulse motor 4, the moving amount s1 of the feed dog 1 when the excitation state is switched from the excitation state ab to the excitation state b is set because of the displacement of the mounting position of the excitation phase and the unevenness of the material. Less than movement amount s (s1
= S-k1 <s: k1> 0). Similarly, the movement amount s2 of the feed dog 1 when the excitation state is switched from the excitation state b to the excitation state bc is larger than the set movement amount s (s2 = s + k2
> S: k2> 0). In this way, the pulse motor 4 is configured to generate a non-uniform movement amount by switching excitation even if the same movement amount command is issued.

Next, the operation of the feeding device of the sewing machine when forming eight continuous stitches will be described.

The total length of the eight continuous stitches is
It is previously set to be “8 × s” based on the set movement amount s.

First, when the forward / backward feed pulse motor 2 is in the two-phase excitation state ab, the first needle drop point is formed.
Subsequently, the feed dog 1 is lifted by the feed dog vertical movement device 4, so that the feed dog 1 projects from the upper surface of the bed portion and comes into contact with the work cloth. Next, the cross feed pulse motor 2
When controlled to the phase excitation state b, the feed dog 1 advances from the position P1 to the position P2 in the forward direction, and the work cloth advances in the forward direction by the movement amount s1 smaller than the set movement amount s. Next, the forward / backward feed pulse motor 2 remains in the one-phase excitation state b, and the feed dog 1
Is lowered and separated from the work cloth. And the second
Needle drop point is formed, the first stitch is formed shorter than a desired length (set movement amount s), and a movement error k1 occurs with the movement of the feed dog 1.

Next, the feed dog 1 is raised so that the feed dog 1 projects from the upper surface of the bed portion and comes into contact with the work cloth.
Next, when the forward / backward feed pulse motor 2 is controlled to the two-phase excitation state bc, the feed dog 1 moves forward from the position P2 to the position P3.
And the work cloth moves forward by a movement amount s2 which is larger than the set movement amount s. Next, the feed dog 1 is lowered and separated from the work cloth while the front-rear feed pulse motor 2 remains in the two-phase excitation state bc. Then, the third needle drop point is formed, and the second stitch is formed longer than the desired length (set movement amount s). Thus, in the present invention, after switching from the excited state ab to the excited state b, the excited state b
By switching from to the excitation state bc, two continuous stitches having the entire length “s1 + s2” are formed.

By the way, when two continuous stitches are formed only by switching a specific excitation state as in the prior art, that is, two continuous stitches are made by switching from the excitation state ab to the excitation state b twice. When the eyes are formed, the length of the formed seam is “2 × s1 = 2 × s1-2 × k
1 ". When two continuous stitches are formed by switching from the excited state b to the excited state bc twice as in the conventional case, the length of the formed stitch is “2 × s2”.
= 2xs2-2xk2 ". Therefore, the movement error of two consecutive stitches of the present invention is "-k1 + k2",
They cancel each other out and become smaller than the conventional movement error “2 × k1” or “2 × k2”.

In this way, the feed dog 1 is sequentially moved, and the stitch is formed. Then, when the forward / backward feed pulse motor 2 becomes the two-phase excitation state ab again, the forward / backward feed pulse motor 2 makes one rotation and all the excitation phases are sequentially excited. Then, the length of eight continuous stitches becomes “8 × s” as desired.

When a switching amount of a certain exciting state causes a moving amount larger than a predetermined moving amount, a switching amount of another exciting state always causes a moving amount smaller than the predetermined moving amount. Therefore, as described above, if all the excitation phases are excited in sequence, a movement amount larger than the predetermined movement amount and a movement amount smaller than the predetermined movement amount are continuous, The movement error caused by each switching is eliminated (8 × s = s1 + s2 +
...).

Further, since the feed dog 1 starts to move forward from the two-phase excitation state and stops in the two-phase excitation state, the feed dog 1 stops accurately at the desired positions P9 and P10. Therefore, a stop error is prevented when moving, and the work cloth can be accurately fed. Further, since the feed dog 1 is stopped backward in the two-phase excitation state, it is possible to prevent a stop error when moving backward. In addition, since it is a 1-2 phase excitation method,
A resolution twice as high as that of the two-phase excitation method can be realized. Therefore, if the feed dog 1 is moved as described above, a good finish can be maintained.

In this embodiment, the case where the seam having the minimum unit length is continuously formed has been described.
As shown in (b) and FIG. 3 (c), even if the stitches having a length that is twice or more that of the stitches are continuously formed, the movement errors cancel each other out, so that the movement errors can be similarly reduced. Further, in the present embodiment, the case has been described in which the excitation states are switched in sequence and then the excitation states for one sequence are switched in reverse, but as shown in FIGS. 2 (c) and 2 (d). Even if the switching is reversed, the movement errors cancel each other out, so that the movement errors are similarly reduced.

In the present embodiment, the case where the excitation is started from the two-phase excitation state ab and the excitation is switched to the two-phase excitation state ab in which the excitation is switched is explained, but it is simply shown in FIG. As shown in b), even if the switching is started in the two-phase excitation state and ended in the two-phase excitation state, the feed dog 1 is accurately stopped, so that the stop error is similarly reduced.

Further, in the present embodiment, the feed dog 1 advances from the left end in the figure to the right direction and retreats to the left end to the left direction again, but as shown in FIG. 1 may proceed from the central portion to the right and then retreat to the central portion to the left again. In this embodiment, the forward / backward feed pulse motor 2 for moving the feed dog 1 in the front / rear direction is controlled so as to reduce an error, but the left / right feed pulse motor 10 for moving the feed dog 1 in the left / right direction is provided. If so, the left and right feed pulse motor 10 may be controlled to reduce the error as described above.

[0032]

As is apparent from the above description, according to the sewing machine feed device of the first aspect of the present invention,
When advancing the feed dog to create a stitch and then advancing the feed tooth to create the next stitch, the excitation state for forming the next stitch is excited by the previous advance. Starting from the excitation phase that has been set, and after switching to all the excitation phases for at least one order, the excitation state is switched in reverse and the feed dog is retracted, so a movement error when the feed tooth moves a lot. And the movement error when the feed dog moves with a small amount cancel each other out, and the movement error due to the movement of the feed dog can be reduced.

According to the sewing machine feed device of the second aspect, the feed dog is advanced from the two-phase excitation state in order to create the first stitch, and then the feed dog is advanced to the next step. When creating a stitch, the excitation state for forming the next stitch starts from the excitation phase excited in the previous advance, and when the advance ends in the two-phase excitation state, the two-phase excitation Since the state is switched from the excitation state to the excitation state and the feed dog is retracted, the stop position of the feed tooth becomes accurate and the stop error due to the stop of the feed tooth is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a sewing machine feeding device of the present invention.

FIG. 2 is a diagram showing a relationship between an excitation state of a pulse motor and a movement of a feed dog in the sewing machine feed device.

FIG. 3 is a diagram showing the relationship between the excitation state of the pulse motor and the movement of the feed dog in the sewing machine feed device.

FIG. 4 is an explanatory diagram showing an excitation state in a pulse motor.

[Explanation of symbols]

 1 Feed dog 2 Forward / backward feed pulse motor 3 Feed control device

Claims (2)

[Claims] 1. A sewing machine feed device for switching the excitation state of a pulse motor having a plurality of excitation phases to move a feed dog forward in the horizontal direction, and switching the excitation state in reverse to retract the feed tooth in the horizontal direction. , When the feed dog is advanced to create one stitch and then the feed dog is advanced to create the next stitch, the excitation state for forming the next stitch is set to the previous advance state. The feed device for a sewing machine, characterized by starting from the excitation phase excited by 1., and after switching to all the excitation phases for at least one order, switching the excitation state in reverse and retracting the feed dog. 2. A feed device for a sewing machine, wherein a pulse motor having a plurality of excitation phases is switched to a 1-2 phase excitation system to change the excitation state and the feed dog is moved in a horizontal direction. After advancing from the two-phase excitation state and then advancing the feed dog to create the next stitch, the excitation state for forming the next stitch is set to the excitation phase excited by the previous advancement. A feed device for a sewing machine, characterized in that when the forward movement is completed in the two-phase excitation state, the two-phase excitation state is switched to the excitation state in reverse to retract the feed dog.