JP2734010B2 - 2-needle square stitch sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a double-needle stitch that forms a stitch parallel to a work cloth with two needles, and that one of the needles is stopped at a corner. Needle bar mechanism capable of performing single needle stitching for forming a stitch, switching means for switching the needle bar mechanism between a double needle stitching state and a single needle stitching state, and a single needle stitching state. The present invention relates to a two-needle corner stitch sewing machine provided with corner stitch stitch setting means for setting the number of stitches to be executed.

[Conventional technology]

First, the inventors of the present application have proposed the following sewing machines. When sewing a corner at the sewing machine,
First, as shown in FIGS. 5 (a) and 5 (b), the number of square stitches In formed by one needle along the seam allowance M and each side edge Wa, Wb of the corner of the work cloth W. By controlling the operation of the sewing machine on the basis of the input data of the sewing machine and the setting data such as the distance between the cloth edge detector and the needle drop point, the basic feed pitch and the reduced feed pitch after the cloth edge detection, Along one side edge Wa,
After forming the parallel stitches S0 along the cloth feeding direction F in the two-needle sewing state, the needle inside the corner is stopped, and the one side edge Wa is stitched in the single-needle sewing state with the needle outside the corner. A stitch S1 corresponding to the number of square stitches In is formed, and then one needle involved in the formation of the stitch S1 is stopped while penetrating the work cloth W at the vertex P0. Work cloth W around one needle
Is rotated to dispose the other side edge Wb of the corner along the cloth feeding direction F, and then the number of stitches S2 equal to the number of square stitches In with respect to the one side edge Wa is formed in a single needle stitch state. Finally, the state is switched to the double needle sewing state.

[Problems to be solved by the invention]

Then, in the above-described sewing machine, as shown in FIG. 5B, in order to secure the seam allowance M and stop the formation of the seam S1 along one side edge Wa of the work cloth accurately at the vertex P0, After detecting the cloth edge, a stitch with a reduced pitch may be formed. In this case, L1 is shifted from the normal position L0 shown in FIG. 5 (a) at the start position of the single needle stitching along the one side edge Wa, and the sewing in the double needle stitching state along the other side edge Wb is performed. At the start,
A problem arises in that an unattractive seam is formed near the vertex P1 of the inner seam.

The present invention has been made in order to solve the above-described problem, and the purpose thereof is that even if the start position of single needle stitching on one side edge of the work cloth is deviated from a normal position,
An object of the present invention is to provide a two-needle corner stitch sewing machine capable of reliably forming a stitch having a good appearance.

[Means for solving the problem]

In order to achieve the above object, in the present invention, a pitch changing means for changing the feed pitch of the work cloth, a detector for detecting the other side edge during sewing on one side edge of the work cloth,
Based on the detection of the other side edge by the detector, in order to stop the formation of the outer stitch at the desired end position in the parallel stitch, the same cloth feeding as before the detection of the other side edge is performed. Calculating means for calculating the number of first stitches for continuing sewing by the pitch and the correction pitch of the second stitch for performing correction stitching by a correction pitch smaller than the cloth feed pitch; When forming a stitch on a side edge, a point in time when sewing is performed by the first number of stitches based on the detection of the other side edge is determined as a change timing of the pitch changing means, and the end position is determined based on the detection of the other side edge. The switching timing from the double-needle stitching state to the single-needle stitching state by the switching means is determined by subtracting the number of stitches one greater than the number of square stitches from the total number of stitches up to the number of stitches. Determined as a work cloth When forming a stitch on an edge, the switching timing from the single-needle stitching state to the two-needle stitching state by the switching means is determined when the number of stitches less than the number of the square stitches is sewn from the end position as a base point. Control means for controlling the switching means in accordance with the switching timing determined by the timing determining means and controlling the pitch changing means in accordance with the change timing determined by the timing determining means Are provided.

[Action]

According to the present invention, when forming a stitch along one side of the work cloth in order to form a seam along the corner of the work cloth, the other side edge of the work cloth is detected by the detector. Then
The calculating means calculates the first number of stitches for continuing the sewing at the same cloth feed pitch as before the detection of the edge and the second number of stitches for performing the corrected stitch at a correction pitch smaller than the cloth feed pitch. I do. The timing determining means determines, at the time of forming a stitch on one side edge of the work cloth, the time when the first number of stitches have been sewn based on the detection of the other side edge of the work cloth as a change timing of the pitch changing means, and The number of stitches one more than the number of square stitches is subtracted from the total number of stitches up to the end position based on the detection of the edge, and the number of stitches is sewn by the number of stitches by the switching means. The timing for switching to the needle stitching state is determined, and when forming a stitch on the other side edge of the work cloth, the time when the number of stitches less than the number of square stitches is sewn from the end position as a base point is set to 1 by the switching means. The timing is determined as the timing of switching from the main needle sewing state to the double needle sewing state. The control means controls the switching means according to the switching timing determined by the timing determining means, and controls the pitch changing means according to the change timing determined by the timing determining means.

[Embodiment] An embodiment of a two-needle corner stitch sewing machine embodying the present invention will be described below in detail with reference to the drawings. As shown in FIG. 2, the arm 1 of the sewing machine constitutes a needle bar mechanism, and a pair of needle bars 4, 5 having needles 2, 3 at the lower end thereof are supported so as to be vertically movable. The switching mechanism including the needle bar switching solenoid 9 shown in FIG. 1 activates the needle bar mechanism to perform two-needle stitching for forming parallel stitches and at the corners of the work cloth W. A single needle stitching state for forming a stitch by stopping one of the needles 2 and 3 is set. If necessary for the details of the needle bar mechanism and the switching means, see Japanese Utility Model Publication No. 55-349 by the same applicant as this application.
See No. 38 and Japanese Patent Publication No. 60-22957.

A light emitter 6a is mounted on a front surface of the arm unit 1 via a bracket 7, and irradiates light to the upper surface of the bed unit 8 at a position intermediate between the two needle drop points and in front of the needle drop points. The bed section 8 is provided with a light receiver 6b constituting the cloth end detector 6 together with the light emitter 6a, and outputs an electric signal corresponding to the amount of received light.

On the other hand, as shown in FIG.
Needle position detector 11, which detects the vertical position of hands 2, 3, Synchronous signal generator 1, which generates a synchronous signal in response to rotation of the sewing machine spindle
2, a pitch changing solenoid 10 which is operated when the cloth feed pitch is changed, a pitch detector 13 for detecting the cloth feed pitch, and an operation pedal 15 for starting and stopping the sewing machine motor 14.
It has. The construction of the needle position detector 11, the synchronization signal generator 12, the pitch detector 13 and the pitch changing solenoid 10 in this embodiment is disclosed in Japanese Patent Application Laid-Open No.
Since it is the same as that described in Japanese Patent No. 17197, further description is omitted. Further, on the front surface of the arm portion 1, a seam allowance key 16 for setting a seam allowance M, a square seam stitch number setting key 17 for setting a square seam Seam In formed in a single seam state, and a single needle Needles 2 and 3 to be paused when setting the sewing state
Is provided, and a numerical display section 19 for displaying the number of square stitches In and the like is provided. The number of square stitches In is set at each of one side edge and the other side edge of the work cloth W.

The control device of the sewing machine in this embodiment includes a CPU 21, and outputs signals from the devices 6, 11, 12, 13, 15 and input signals based on operation of the keys 16 to 18 through an interface 22.
Is input to the CPU 21 via the. The CPU 21 stores the sewing allowance M, the number of square stitches In, the data of the pause needle, and the like.
M23 and a ROM 24 for storing the program. Then, the CPU 21 executes the control program of the ROM 24 and the RAM 23
Based on the stored data, the operation of the sewing machine motor 14, the pitch changing solenoid 10, the needle bar switching solenoid 9, and the numerical value display unit 19 are controlled via the interface 25 and the respective drive circuits 26, 27, 28, 29.

Further, the CPU 21 calculates the feed amount transferred between the time when the other side edge Wb is detected during sewing on one side edge Wa of the work cloth W and the next time when the needles 2 and 3 penetrate the work cloth W. Along with
A correction stitch number J as a second stitch number is appropriately set, and based on the feed amount data, a preset basic fabric feed pitch, and the correction stitch number J (3 in this embodiment). , A reduction correction pitch smaller than the basic cloth feed pitch,
A first stitch number K to be sewn at the basic cloth feed pitch is calculated. This arithmetic processing is described in Japanese Patent Application Laid-Open No. 61-217197.
Please refer to it if necessary because it is described in the publication.

Then, based on the calculation result, the CPU 21 switches from the double-needle sewing state to the single-needle sewing state during a period from the detection of the other side edge Wb of the work cloth W to the vertex P0.
And the start timing of the correction sewing by the reduction correction pitch, and the timing T2 for switching from the single needle sewing state to the double sewing state after the work cloth W is turned at the vertex P0 is set.

Here, when the number of stitches from the cloth edge detection to the vertex P0 is N, the former needle bar switching timing T1 is N after the cloth edge detection.
The needle bar switching timing T2 is set at the time when the number of stitches represented by − (In + 1) is sewn, and the latter needle bar switching timing T2 is set at the time when the number of stitches represented by In−1 is sewn with the vertex P0 as the base point. The timing of the start of the correction sewing is K
It is set when sewing is performed for the number of stitches represented by (= N-J). The timing of starting the correction sewing is K (= N−
J) is set.

Now, in the sewing machine configured as described above,
According to the data such as the seam allowance M, the number of square stitches In, the rest needle (the left hand needle 3), the basic cloth feed pitch, and the like stored in the RAM 23, the work cloth W shown in FIGS. A case where stitches are formed along each part will be described.

First, in the flowchart of FIG. 3, step S1
As shown in FIG. 7, when the operation pedal 15 is depressed forward, the CPU 21 drives the sewing machine motor 14 via the drive circuit 26 in response to the operation to drive the sewing machine, and one side edge Wa of the work cloth W. To form a parallel seam S0. Then, when the other end Wb of the work cloth W is detected by the cloth end detector 6 in accordance with the operation of the sewing machine, the CPU 21 performs the above-described arithmetic processing to reduce the first number of stitches K by the basic cloth feed pitch. The second stitch number J based on the correction pitch, the operation timings T1 and T2 of the needle bar switching solenoid 9, and the pitch changing solenoid 1
An operation timing of 0 is obtained (S2, S3).

Then, while counting the number of stitches based on the pulse generated from the needle position detector 11, the CPU 21 forms stitches S0 for a predetermined number of stitches [N− (In + 1)] in the double-needle stitching state. When the sewing up to the sewing start position L1 in the single-needle sewing state shown in FIGS. 4 (a) and 4 (b) is completed (S4, S5), the CPU 21
Activates the needle bar switching solenoid 9, deactivates the previously selected left needle 3, and sets the single needle stitching state with the right needle 2 (S6).

Thereafter, while counting the number of stitches, the CPU 21 forms the stitch S1 in accordance with the aforementioned stitch number (In + 1) (S7, S7).
8). At the time of sewing during this time, the CPU 21
A pitch reduction operation is performed as necessary based on the calculation results of the second stitch numbers K and J. Then, after forming the stitches S1 for the number of stitches (In + 1), the CPU 21 stops the right needle 2 at the needle lower position at the vertex P0 of the corner and penetrates the work cloth W (S9). In this state, the worker raises the work clamp (not shown), and then turns the work cloth W around the needle 2 in the counterclockwise direction in FIGS. 4 (a) and 4 (b). Is arranged along the cloth feeding direction F.

Next, when the presser foot is lowered and the operation pedal 15 is depressed forward by the operator, the CPU 21 resumes the operation of the sewing machine in the single-needle sewing state, and counts the number of stitches (S9a, S10). ). Then, when the stitches S2 of the number of stitches (In-1) are formed along the other side edge Wb of the work cloth W by only the right needle 2 (S10, S11), the CPU 21 performs the needle bar switching. By operating the solenoid 9, the rest state of the left needle 3 is released, and the state is switched to the double needle sewing state (S12). Then, the sewing machine is operated in a two-needle stitching state, and stitches S3 (including S3s)
Is formed (S13).

At the time of the above sewing, as shown in FIG. 4 (a), when sewing along one side edge Wa of the work cloth W, the inner vertex P1 is used.
When the distance X between the position L1 at which the switching from the double-needle sewing state to the single-needle sewing state is performed is substantially equal to one basic cloth feed pitch, that is, the single-needle sewing is started at a regular position. In this case, it is not necessary to reduce the cloth feed pitch before the sewing at the one side edge Wa is completed, and as shown in FIG. 4 (a), the ideal stitches along the sewing locus 1, l2 can be obtained. It is formed.

On the other hand, as shown in FIGS. 4B and 4C, when the interval X is shorter than the basic cloth feed pitch, it is necessary to reduce the cloth feed pitch, and the cloth feed pitch is actually reduced. Correction stitching corresponding to the second stitch number J is performed. Therefore, in this embodiment, the timing of switching to the single needle stitching state at the time of single needle sewing before turning the work cloth W is set earlier by one stitch than the set number of square stitches In, so that the double needle stitching is performed. The formation position of the last stitch S0e is separated from the vertex P1. Also, at the time of single-needle sewing after turning the work cloth W, the switching timing to the double-needle sewing state is advanced by one stitch from the set number of square stitches In, and when the double-needle sewing state is restarted, A seam S3s following the seam S0e is formed.

Therefore, all the stitches including the stitch S3s are formed on the ideal sewing trajectories 1 and l2, and it is possible to prevent the appearance from becoming worse.

〔The invention's effect〕

As described in detail above, the present invention makes it possible to reliably form a good-looking stitch even if the start position of single-needle stitching on one side edge of the work cloth is deviated from a normal position. Demonstrates excellent effects.

[Brief description of the drawings]

1 is a block diagram showing a control device of a two-needle angle stitch sewing machine embodying the present invention, FIG. 2 is a partial front view of the sewing machine, FIG. 3 is a flowchart, and FIGS. 4 (a) and (b). Is an explanatory view showing a sewing example, and FIG. 4C is a partially enlarged view of the sewing example. FIGS. 5 (a) and 5 (b) are explanatory views showing examples of sewing using a conventional sewing machine. 2,3 ... needle, 6 ... cloth end detector, 9 ... needle bar switching solenoid as switching means, 10 ... pitch changing solenoid as pitch changing means, 17 ... square stitch setting means Number of stitch setting keys, 21... CPU as arithmetic means, timing determining means and control means, W... Work cloth, Wa ... one side edge, Wb ... other side edge, In ... square sewing Number of stitches, K: number of first stitches, J: number of second stitches.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-49188 (JP, A) JP-A-59-197284 (JP, A) JP-A-61-217197 (JP, A) JP-A-58-1983 49179 (JP, A) JP-A-1-308588 (JP, A) JP-A-63-272389 (JP, A)

Claims (1)

(57) [Claims] 1. A two-needle stitch for forming a stitch parallel to a work cloth with two needles and a one-needle stitch for stopping a stitch at a corner to form a stitch. A possible needle bar mechanism, a switching means for switching the needle bar mechanism between a double needle sewing state and a single needle sewing state, and a single needle sewing state on one side edge and the other side edge of the work cloth A pitch changing means for changing a feed pitch of a work cloth in a two-needle corner stitch sewing machine provided with a square stitch seam setting means for setting the number of stitches to be set, A detector for detecting the other side edge, based on the detection of the other side edge by the detector, for stopping the formation of outer stitches in the parallel stitches at a desired end position, First stitch for continuing sewing with the same cloth feed pitch as before the detection of the other side edge Calculating means for calculating the number and the correction pitch of the second stitch for performing the correction stitching with a correction pitch smaller than the cloth feed pitch; and when forming the stitch on one side edge of the work cloth, the other side edge Is determined as the change timing of the pitch changing means with the detection of the other side edge as the base point, and the square stitches are calculated from the total number of stitches up to the end position based on the detection of the other side edge. The time when sewing is performed by the number of stitches obtained by subtracting the number of stitches one greater than the number of stitches is determined as the switching timing from the double-needle sewing state to the single-needle sewing state by the switching means. At the time of forming the stitches, a point in time when the number of stitches less than the number of the square stitches is sewn from the end position as a base point as the switching timing from the single needle stitching state to the double needle stitching state by the switching means. Control means for controlling the switching means according to the switching timing determined by the timing determining means and controlling the pitch changing means according to the change timing determined by the timing determining means; A two-needle sewing machine characterized by comprising: