RU2129175C1 - Method for making large length stitches on program-controlled embroidery machine - Google Patents

Abstract

FIELD: sewing equipment. SUBSTANCE: method involves providing displacement of blank along stitch path before making intermediate puncture, with signals of positioning sensor mounted on main shaft of embroidery machine being taken into account; receiving inhibiting signal; providing movement to remaining part of stitch upon delivery of positioning permitting signal after following lifting of needle. EFFECT: simplified control of embroidery machine during making of elongated stitches and increased efficiency. 2 dwg

Description

 The invention relates to sewing equipment, in particular to shuttle stitch embroidery machines, and can be used in embroidery machines when making long stitches.

 Modern embroidery machines are characterized by a high degree of automation, allowing you to sew various patterns by embroidery in automatic mode. The principle of operation of automatic embroidery machines is to move the workpiece fixed in the hoop by the size of one stitch in the time interval between the exit of the needle from the fabric and the subsequent entry of the needle into the fabric. This movement is carried out by two stepper motors along the X and Y axes, respectively, according to the control system signals in accordance with the selected program. Since the needle makes a continuous reciprocating movement, the time of possible movement of the fabric is strictly limited and depends on the sewing speed: the higher the sewing speed, the shorter the time remaining for moving the fabric and the shorter the stitch length.

 Given the highest speed of modern stepper motors, the longest stitch length of 10 - 12 mm can be carried out at a speed of 120 - 200 rpm for the best embroidery machines of BROTHER (Japan), TALMA (Japan) and others. Since working at this speed does not provide high productivity, there are a number of technical solutions that allow you to work at higher speeds when making long stitches.

 Japanese Accepted Application No. 2-32391, cl. D 05 C 5/04, 1990 the working sewing speed is adjustable and set inversely with the length of the stitch to be programmed. This dependence is implemented on almost all embroidery machines of leading companies, however, when embroidering, stitches may be found whose length does not allow them to be sewn even with a significant decrease in sewing speed.

 In this case, they either resort to stopping the needle bar when making long stitches, as suggested in German application N 4212870, cl. D 05 B 3/02, 1992, or to perform an intermediate injection, which divides the long stitch into several components, each of which can be performed at a given sewing speed, which is proposed in the accepted application of Japan N 3-34754, class. D 05 B 21/00, 1991.

 In the first case, for the implementation of long stitches, an additional mechanism for stopping the needle bar when the drive is running is necessary, which is a rather difficult technical task associated with additional material costs.

 In the second embodiment, the problem is solved by the computing device of the control system. As the closest analogue to the invention, a method for making long stitches on a programmed embroidery machine, described in Japanese Accepted Application No. 3-34754, class. D 05 B 21/00, 1991. It consists in issuing a permission signal for moving the workpiece at the moment the needle leaves the fabric, moving the workpiece by the size of the stitch in accordance with the embroidery program, performing an intermediate injection when converting the limit value of the stitch length for one working stroke of the needle.

 The technical solution according to the application of Japan N 3-34754 is also not without drawbacks.

 Firstly, it requires constant comparison of the stitch coming to embroidery with the limit value of the stitch length for a given sewing speed and, if the length of the stitch coming to embroidery exceeds the permissible one, the coordinates of intermediate injections are divided, dividing the stitch length into several components, each of which should be less limit value. This loads the computing device with additional work, which requires high-speed computing device.

 Secondly, control and comparison of the distance between two injections, i.e. stitch length with the maximum permissible value, can lead to loss of productivity, because this value does not always characterize the capabilities of the machine.

 Let us explain an example. It is well known that in embroidery machines the movement of the fabric by the size of the stitch is carried out by two stepper motors, respectively, at the coordinates X and Y. The longest stitch length, which can be done at the time when the needle does not enter the fabric, is determined by the maximum number of steps that each engine has time to complete during this time interval.

When the direction of the stitch coincides with the X or Y axis, the longest stitch length is determined by the ratio
L _max = t _o • n _max ,
where t _o - the amount of movement of the workpiece for 1 step of a stepper motor (discreteness of movement);
n _max is the largest number of steps that a stepper motor manages to complete during the time between the exit of the needle from the fabric and the subsequent entry of the needle into the fabric.

This value L _max and is taken in the prototype for comparison with the stitch length without taking into account the direction of the stitch relative to the axes X - Y.

Численное значение

определяется из соотношения

но так как шаговые двигатели осей X и Y одинаковы, то L_{max x} = L_{max y}, а наибольшая длина стежка

Таким образом, наибольшая расчетная длина стежка L_max всегда меньше теоретической

, поэтому производительность машины используется не в полной мере.If the direction of the stitch were taken into account, then the largest feasible stitch length could be with the simultaneous greatest movement of both stepper motors, i.e.:

Numerical value

determined from the relation

but since the stepper motors of the X and Y axes are the same, then L _{max x} = L _{max y} , and the longest stitch length

Thus, the maximum calculated stitch length L _{max is} always less than theoretical

, therefore, the performance of the machine is not fully utilized.

 The technical result of this invention is to simplify the management of the embroidery machine when making long stitches with a simultaneous increase in productivity when performing them.

 The technical result is achieved due to the fact that in the method of making long stitches on an embroidery machine with program control, which consists in issuing a permission signal to move the workpiece at the moment the needle leaves the fabric, move the workpiece by the amount of stitch in accordance with the embroidery program, and perform an intermediate injection with exceeding the limit value of the length of the stitch for one working stroke of the needle, according to the invention, the movement of the workpiece along the path of the stitch before an intermediate injection is carried out taking into account the signals of the positioning sensor installed on the main shaft of the embroidery machine until a prohibitory signal is received from it, and moving to the remainder of the stitch is carried out after the resolving signal of the positioning sensor during the subsequent needle raising.

 The invention is illustrated in the graphic part, where in FIG. 1 shows an embroidery machine and its main components for implementing this method, and in FIG. 2 - details of the positioning sensor.

 The embroidery machine consists of a table 1, on which a sewing head 2 is installed, a manipulator 3 for moving the hoop 4 along the X and Y axes, and a control unit 5.

 The sewing head 2 is equipped with several needle bar 6, which reciprocates the main shaft 7, on which a positioning sensor 8 is installed, consisting of a rotating shutter 9 and a sensing element 10. When the shutter 9 enters the gap of the sensing element 10, a permissive tissue movement signal is issued, and when the curtain comes out - a prohibition signal.

 The embroidery machine operates as follows.

 When executing a given embroidery program, the main shaft 7 receives a rotational movement, which is converted into the reciprocating movement of one of the needle bar 6. The manipulator 3, according to the signals of the control unit 5, in accordance with the embroidery program moves the hoop 4 synchronously with raising the needle by the size of the stitch. The stitch starts when the needle leaves the fabric by the enable signal of the positioning sensor 8 and ends when the end point of the stitch is reached. If, before reaching the end point of the stitch, a prohibiting signal from the positioning sensor is received, the hoop is paused, the machine performs an intermediate injection and the manipulator continues to move the fabric along the interrupted path to the end point of the stitch using a new resolution signal from the sensor.

 Thus, depending on the programmed stitch length and embroidery speed, the stitch can be performed in one or more movements of the manipulator with intermediate injections. In this case, the coordinates of the intermediate injections are not calculated and not controlled, and the moment of interruption of the feed is determined by the inhibitory signal of the positioning sensor.

 The use of the invention allows to simplify the control of the embroidery machine when making long stitches with a simultaneous increase in productivity when performing them.

Claims (1)

 The way to make long stitches on a programmed embroidery machine, which consists in issuing a signal for placing the workpiece moving at the moment the needle leaves the fabric, moving the workpiece by the amount of stitch in accordance with the embroidery program, performing an intermediate injection when exceeding the limit value of the stitch length in one working stroke needles, characterized in that the movement of the workpiece along the path of the stitch before the intermediate injection is carried out taking into account the signals installed on the main shaft of the embroidery m tire positioning sensor to obtain from it prohibiting signal, and moving the remainder of the stitch is performed after allowing the positioning of the sensor signal at the next rise of the needle.

Images