JPH0211278B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a sewing machine that sews workpiece cloth with a constant stitch width by detecting the edge of the cloth and stopping the needle at a fixed position. [Prior Art] In order to sew a workpiece cloth with a constant stitch width as shown in FIGS. 7 and 8, for example, at points C1, C2, and C3 where the direction of the seam line changes, the distance from the edge of the cloth must be adjusted. must be the same as the stitch width. For example, if the distance between the START point and point C1 is not an integral multiple of the regular stitch width, point C
The fabric feed for the last 1st or 2nd stitch immediately before 1st stitch is performed at a fabric feed amount (corrected fabric feed amount) that is less than the regular fabric feed amount, so that the needle drops at the point C1. [Problem to be solved by the invention] However, if the number of revolutions (number of stitches) of the sewing machine motor when sewing at the regular cloth feed rate is
If it is 3500 spm, the rotation speed of the sewing machine motor when forming the final one or two stitches with this corrected cloth feed amount will be reduced to, for example, 500 spm, and further,
Just before the sewing machine stops, the speed must be further reduced to, for example, 200 spm. In particular, two to three stitches were required to reduce the speed to 500 spm. Therefore, after detecting the fabric edge, until the needle stops, it takes 4~
This requires 5 stitches. Here, the distance H between the needle hole and the fabric edge detection means, the stitch width W, the feed pitch P, and the number of stitches required until the needle stops after detecting the fabric edge are N.
Then, there is a relationship of N=(H-W)/P,
Depending on the selection of each numerical value, there may be cases where this relationship is not satisfied, and in this case, there is a problem that the hands do not stop at a fixed position. [Problems to Solve the Problems] This invention was made by focusing on the above-mentioned conventional problems.When the sewing machine cannot be stopped at a fixed position with the set value, the sewing machine is stopped from starting. The purpose of this system is to use a calculation means to calculate the number of stitches required from detecting the edge of the fabric to stopping the needle after detecting the edge of the fabric, and calculate the number of stitches and the number of stitches required from detecting the edge of the fabric to stopping at a fixed position. By comparing the required number of stitches,
Based on the results of this comparison, the start preventing means prevents the sewing machine from starting, and the notifying means notifies the user that it is impossible to stop the needle in a fixed position. [Embodiment] An embodiment of the present invention will be described based on FIGS. 1 to 16. FIGS. 2 to 5 are diagrams showing each part of the cloth feeding mechanism and cloth feeding amount adjustment mechanism. In the figure, reference numeral 10 denotes a well-known cloth feeding means disposed on the underside of the bed, which includes a horizontal movement mechanism consisting of a feed bar 10a, a feed locker 10b, a shaft 10c, a rod 10d, and a connecting rod 10e, and an arm 10.
It consists of a vertical mechanism consisting of a shaft 10g, a shaft 10g, and a continuous rod 10h. In the horizontal movement mechanism, the connected rod 10e provides horizontal movement to the rod 10d in conjunction with the eccentric cam 12 fixed to the main shaft 11, and then this horizontal movement is applied to the feed bar via the shaft 10c and the feed bar rocker 10b. 10a, and the feed dog 13 moves horizontally. On the other hand, in the vertical movement mechanism, the connecting rod 10h is linked to the eccentric cam 12 and vertically moves the clamping part 10f fixed to the shaft 10g, and the pair of opposing arms 10f1, 10f2 of the clamping part 10f A vertical motion is applied to the feed bar 10a through a slide block 10a1 that fits into the feed bar 10a, and the feed dog 13 is moved vertically. Therefore, due to this horizontal movement and vertical movement, the feed dog 13 moves in an elliptical manner. 15 is an adjustment screw 15a, an adjustment cam 15b, a rod 15c, a feed adjustment shaft 15d, and an arm 1.
5e, 15f, connecting rod 15g, rocker arm 15h, rocker 15i, hinge pins 15j, 15k, 15l, and spring 15m. Adjustment cam 15b is rotated counterclockwise by spring 15m via rod 15c. The adjustment screw 15
The forward and backward movement of a causes the contact position of the adjustment cam 15b to change, and the feed adjustment shaft 15d rotates via the rod 15c and arm 15e. As a result, this rotation is transmitted to the rocker arm 15h and rocker 15i via the arm 15f and connecting rod 15g, causing the hinge pin 15k to move up and down. Therefore, hinge pin 1
The position of the hinge pin 15k changes with respect to the line L connecting the respective axes of the rocker 15j and the hinge pin 15l, and the horizontal motion component W1,
W2 changes as shown in FIGS. 5a and 5b. Note that during reverse feeding, the hinge pin 15k is located below the line L. Reference numeral 20 denotes a substantially L-shaped reverse feed adjustment lever having a lever portion 20a and an arm portion 20b. A spring 2 stretched between the frame and the arm portion 20a
1, and is engaged with a stopper pin 22 provided on the machine frame. Reference numeral 23 denotes a swinging arm, one end of which is fixed to the feed adjustment shaft 15d, and the other end of which is fixed to the feed adjustment shaft 15d.
3a is connected to a shaft 26a of a potentiometer 26, which will be described later, via links 24 and 25, and its upper surface abuts against a pin 20c provided on the reverse feed adjustment lever 20. The reverse feed adjustment lever 2
The counterclockwise rotation of 0 rotates the feed adjustment shaft 15d together with the swing arm 23 in the counterclockwise direction. Reference numeral 27 denotes a substantially L-shaped operating lever, the elbow portion of which is loosely fitted onto the feed adjustment shaft 15d, and a pin 27Aa provided at one end abutting against the upper surface of the swinging arm 23. This other end is rotatably connected to one end of the connecting arm 28. 29 is a substantially L-shaped operating rod, the center part of which is rotatably supported by the machine frame, and the arm extending downward is connected to the connecting arm 28.
It is rotatably connected to the end portion 28a of. Further, a forked portion provided on the arm extending to the right engages with a pin 30b provided on the plunger 30a of the solenoid 30. Reference numeral 31 denotes a cam body provided opposite to the end 28a of the connecting arm 28, and its wall thickness is changed by one step rotation of the stepping motor 32 so as to change the cloth feed pitch by 0.424 mm. The cam body 31 forms a cam over approximately 180 degrees, and is connected to a stepping motor 3 with a resolution of 1.8 degrees.
2, the cloth feed pitch can be adjusted from 0mm with a total of 115 pulses.
It can be set to 2.5mm. The end portion 28a of the connecting arm 28 separates from the cam surface when the solenoid 30 is not activated, and separates from the cam surface 31 when the solenoid 30 is activated.
a. The solenoid 30 and the stepping motor 3
2. The cam body 31, the connecting arm 28, the operating lever, the operating rod 29, etc. constitute cloth feed amount changing means for setting the corrected cloth feed. In FIG. 6, 40 is composed of a sensor for detecting the edge of the cloth, a light emitter 40a, and a light receiver 40b. 41 is the throat plate, 41a is the needle hole, 4
2 is a presser foot, and 43 is a needle. In FIG. 1, 50 is a cloth feed section detection circuit for detecting the cloth feed section, 51 is a pulse detection circuit,
Pulses from an encoder 52 provided on the main shaft are detected. This encoder 52 generates 100 pulses for one rotation of the main shaft 11. A needle position detection circuit 53 detects the upper and lower positions of the needle according to the rotation angle of the main shaft 11 and outputs an upper position signal and a lower position signal, respectively. 54 is a tachometer for speed detection, and 55 is a motor, which rotates the main shaft 11 via a belt and a pulley. 56 is a motor drive control circuit for driving and controlling the motor 55, and 57 is a cloth edge detection circuit, which together with the sensor 40 constitutes cloth edge detection means. 58 is a sensitivity adjustment circuit that adjusts the sensitivity of the sensor circuit according to the thickness of the cloth, etc. 59 is an origin detection circuit fixed to the shaft of the stepping motor 32, and the connecting arm 28 corresponds to feed pitch 0. The rotation angle at the time of contact with the cam surface is detected as the origin. 60 is an A/D converter for A/D converting an analog signal from a potentiometer; 61 is a motor drive circuit for driving the stepping motor; 62 is a solenoid drive circuit for driving the solenoid; 63 is a counter; The pulses obtained by ANDing the signals from the panel detection circuit 51 and the cloth feeding period detection circuit 50 are counted.
Further, it is reset by a pulse obtained by ANDing the levels of the lower position signals of the cloth edge detection circuit 57 and needle position detection circuit 53. 64 is a microcomputer with CPU (central processing unit),
It consists of ROM and RAM. The contents of Table 1 below are stored in the ROM. This table 1 is
This is for calculating the amount of cloth feed from the time of cloth edge detection to the end of the cloth feeding period immediately after the cloth edge detection based on the rotation angle of the main shaft at the time of cloth edge detection.

〔Effect of the invention〕

As explained above, if the stitch width, feed pitch, and distance between the needle hole and the material edge detection means are set inappropriately, this invention prevents the sewing machine from starting and also indicates that the settings are incorrect. This has the effect of making a notification and stopping the needle at a fixed position.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of the cloth feed mechanism and cloth feed amount adjustment mechanism, FIG. 3 is a view showing the corrected cloth feed amount setting mechanism, and FIG. Figure 3 is an exploded perspective view of the main parts, Figures 5a and 5b are explanatory diagrams for setting the cloth feed amount, Figure 6 is a diagram showing the placement position of the sensor, and Figure 7 is an example of stitching with a constant stitch width. 8 is a partially enlarged view of FIG. 7, FIG. 9 is a diagram showing the relationship between needle position and cloth feed, FIGS. 10 and 11 are operation timing charts, and FIGS. Figure 16 is an operational float chart. In the figure, 40 is a sensor, 57 is a cloth edge detection circuit, 64 is a computer, and 65 is an error indicator.

Claims (1)

[Claims] 1. In a sewing machine that sews workpiece cloth with a constant stitch width by detecting the fabric edge with a fabric edge detection unit and stopping the needle in a fixed position, the distance between the needle hole and the fabric edge detection unit, the stitch width, and the feed Calculating means for calculating the number of stitches required to stop the needles after detecting the edge of the fabric from the pitch, and comparing means for comparing the calculated number of stitches with the number of stitches required to stop the stitches after detecting the edge of the fabric;
A sewing machine comprising a notification means for notifying that the needle cannot be stopped based on the comparison result, and a start prevention means for preventing the sewing machine from starting based on the comparison result.