JPH0211279B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention detects the edge of the fabric and stops the needle at a fixed position, thereby stitching the fabric at a constant stitch width.
The present invention relates to a sewing machine for sewing, and particularly to a sewing machine in which the distance between a cloth edge sensor and a needle hole can be changed and set. [Prior Art] In order to sew a workpiece cloth with a constant stitch width W as shown in FIGS. 9 and 10, 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
For the corrected fabric feed of the last 1st or 2nd stitch immediately before 1st stitch, calculate the corrected fabric feed amount that is less than the regular fabric feed amount, and change the setting to this corrected fabric feed amount so that the needle drops at the point C1. There is. By the way, depending on the processed cloth and sewing method, etc.
Since feed dogs such as 1 or 4 teeth are used,
The throat plate is replaced according to the number of feed dogs. Normally, these throat plates are equipped with a sensor for detecting the edge of the fabric, and in order to locate the sensor in a position where it does not get in the way of the feed dog, the distance H between the needle hole and the edge sensor is Not constant (Fig. 8b,
c). In addition, when sewing with a large stitch width, the difference from the above-mentioned distance H may become small and it may be difficult to stop at a fixed position. In some cases, multiple units were installed at various locations. [Problems to be Solved by the Invention] However, there is a method in which the corrected cloth feed amount, which is less than the normal cloth feed amount, is determined by detecting the cloth edge, determining the length from the original sewing point to the cloth edge, and using this as a reference. So,
As mentioned above, when the distance between the needle hole and the material edge sensor changes, such as when the throat plate is replaced, the values stored in the sewing machine must be changed. I was unable to operate it. [Means for Solving the Problems] The present invention has been made in view of these conventional problems, and provides a sewing machine that can change and set the distance between the fabric edge sensor and the needle hole. . [Embodiment] An embodiment of the present invention will be described based on FIGS. 1 to 17. 4 to 7 show each part of the cloth feeding mechanism and cloth feeding amount adjusting 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 1.
0f, a shaft 10g, and a connecting 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, the vertical movement mechanism includes a holding portion 10f in which a connecting rod 10h is fixed to a shaft 10g in conjunction with the eccentric cam 12.
vertical movement is applied to the opposing 1 of this clamping part 10f.
A vertical movement is applied to the feed bar 10a via a slide block 10a1 fitted to the pair of arms 10f1 and 10f2, and the feed dog 13 is moved vertically. Therefore,
Due to this horizontal movement and vertical movement, the feed dog 13
moves in an ellipse. 15 is an adjustment screw 15a, an adjustment cam 15b, a rod 15c, a feed adjustment shaft 15d, arms 15e, 15f, a connecting rod 15g,
A cloth feed amount adjustment mechanism composed of a rocker arm 15h, a rocker 15i, hinge pins 15j, 15k, and 15l, and a spring 15m, and an adjustment cam 15b are urged to rotate counterclockwise by a spring 15m via a rod 15c. Adjustment screw 1
The forward and backward movement of 5a changes the contact position of adjustment cam 15b, and the feed adjustment shaft 15d rotates via 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. 7a and 7b. 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. and a spring 21 stretched between the arm portion 20a.
It is urged upward by the machine frame and engages 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 23.
A 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 20
The counterclockwise rotation causes the feed adjustment shaft 15d to rotate 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 the connecting arm 2
It is rotatably connected to one end of 8. Reference numeral 29 denotes a substantially L-shaped operating rod, whose central portion is rotatably supported by the machine frame, and whose downwardly extending arm is rotatably connected to the end 28a of the connecting arm 28. Also,
The forked part provided on this arm extending to the right is a pin 30 provided on the plunger 30a of the solenoid 30.
b. Reference numeral 31 denotes a cam body disposed opposite the end 28a of the connecting arm 28, and its wall thickness is changed so as to change the cloth feed pitch by 0.0242 mm by one step rotation of the stepping motor 32. The cam body 31 forms a cam over approximately 180 degrees, and a stepping motor 32 with a resolution of 1.8 degrees allows the cloth feed pitch (corrected cloth feed amount) to be set from 0 mm to 2.5 mm with a total of 59 pulses. .
The end 28a of the connecting arm 28 is connected to the solenoid 3.
When it is inactive, it separates from the cam surface, and when it is in action, it comes into contact with the cam surface 31a. In FIG. 8a, 40 is composed of a sensor for detecting the edge of the cloth, a light projector 40a, and a light receiver 40b, and the light receiver 40b is disposed on the needle plate 41. 41a is a needle hole, 42 is a presser foot, and 43 is a needle. Figures b and c show the distance H between the needle hole and the sensor on the throat plate when the sewing machine has three and four feed teeth, respectively. In FIG. 1, 50 is a cloth feed section detection circuit for detecting a cloth feed section, and 51 is a pulse detection circuit, which detects pulses from an encoder 52 provided on the main shaft. 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 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 axis of rotation when it comes into 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 pulse 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 the 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 to calculate 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〕

Since the present invention has the above-described configuration, even when the distance H between the needle hole and the cloth edge sensor is changed by replacing the throat plate, etc., a means is provided to change the distance H between the needle hole and the cloth edge sensor. In response to this, it became possible to stop the sewing machine in a fixed position.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a specific example of a sensor distance setting device, and FIG. 3 is a diagram showing another specific example of the sensor distance setting device, FIG. 4 is an exploded perspective view of the cloth feeding mechanism and cloth feeding amount adjustment mechanism, FIG. 5 is a diagram showing the cloth feeding amount setting mechanism, and FIG. The figure is an exploded perspective view of the main part of Figure 5, Figures 7a and b are explanatory diagrams for setting the cloth feed amount, Figure 8 is a diagram showing the sensor placement position, and Figure 9 is a diagram showing the stitch width at a constant stitch width. Figure 10 showing an example of the stitch position of
The figure is a partially enlarged view of Figure 9, Figure 11 is a diagram showing the relationship between needle position and cloth feed, Figures 12 and 13 are operation timing charts, and Figures 14 to 1.
7 are operation flowcharts. 40...sensor, 41a...needle hole, 64...
Computer, 10... cloth feeding means, 11... main shaft.

Claims (1)

[Scope of Claims] 1. A throat plate provided with a needle hole through which the needle passes vertically and at least one cloth edge sensor that detects the cloth edge, the distance between the needle hole of the throat plate and the cloth edge sensor, and the stitch width. , and means for setting the fabric feed amount on the sewing machine, the number of stitches from the needle drop point after the fabric edge sensor detects the fabric edge until the sewing machine stops at a predetermined position, and the corrected feed amount below the fabric feed amount. A sewing machine that calculates and stops forming a seam at a predetermined position, wherein the setting value can be changed when the distance between the fabric edge sensor and the needle hole is changed.