DD219048A3 - CIRCUIT ARRANGEMENT OF AN AUTOMATIC PUNCHING AND STITCHING ADJUSTING DEVICE - Google Patents

Abstract

The solution according to the invention is used for realizing a constant distance from the last needle penetration of a sewing machine to a reference edge (for example the edge of the sewing edge), independently of the operator. According to the invention, a sewing machine has a main shaft position sensor G1, a stitch number sensor G2, a material edge detection sensor G3, and a count and evaluation controller. The main shaft position is classified on reaching the Naehgutkante according to their crank angle in at least 4 areas. According to this classification, a control of the Stichlaengenverstelleinrichtung and / or a change in the preselected number of stitches takes place. Fig. 3

Description

Circuit arrangement of an automatic stitch length and stitch

numberverification ''

Field of use:

The invention relates to a, automatic Stichlängen- and Stichanza.hlverstelleinrichtung on mechanized or automated sewing machines for the realization of a constant distance from the last Nadeleinstich to, for example, the Nähgutrand regardless of the Bed.ienperson,. ''

, Characteristic of the known technical solutions:

The quality of a seam with certain seaming properties is determined, among other things, by the uniform spacing of the seam formed from the edge of the sewing seam. For suture types that require a change of direction, such as. z, B · when Absteppeh collar and flaps the pierced in the fabric needle in the corner is expediently used as a rotation axis. In order to allow the same distance from the formed seam to the Nähgutrand as in the previous seam section after turning the material in the new sewing direction, is

* Using conventional sewing machines, the seamstress should make sure that the seam distance is maintained. For this purpose, kuT2i will reduce the sewing speed before reaching the corner and by changing the stitch length try to get the last needle penetration exactly. Such an operation is associated with a more or less large loss of time. Those products which work with known proximity sensing edge scanning drives allow high speed stitching

Number of stitches up to the last stitch, but the requirement for 'observance of an exact distance from the last puncture to ^{: seen} to Uähgutkante in Hährichtung, - meet only inaccurate, ie, with an inaccuracy of at least one stitch length,

In DE-OS 3,018,797 eiiie sewing machine is now described with a Stichzahlkorrektureinrichtung, which in response to the position of the ITähmaschinen¬ main shaft at the time of signaling by an external light barrier, which detects the Kahgutende, the number of stitches to be stitched to sum last stitches then 1 stitch corrected if the main ITA machine shaft is just in a specific area. With this device it is achieved that the deviation of the last recess from a reference edge is only - 1/2 stitch. But even this deviation, it is still absolutely 1 stitch, is for many

T5 applications are not sufficient yet.

Object of the invention:

The object of the invention is to provide a device which allows the remaining deviation of the last recess from a reference edge to be substantially reduced and thus the applicability of such sewing machines to be increased.

presentation; the essence of the invention:

The invention has for its object to provide a circuit arrangement which makes it possible to keep the difference of, distance de3 last puncture a! Seam from a reference edge very _(small. According to the invention solved gave up by providing a sewing machine a Hauptwellenst'ellungssensor G1, a stitch count sensor G2, a Hähgutkantenerkennungsson3or G3 and a counting and evaluation control has .The latter consists of a starting device, two Zählketten and, two Teilauswerte-

30, controls. The incoming during sewing constantly in the counting chain 1 pulses of the main shaft position sensor G1 are in

, Moment of the output from the Nähgutkantenerkennungssensor G3 pulse stored. The main shaft position is classified according to its crank angle in at least 4 areas »According to this classification, a control of the 'Sticiilängenverstelleinrichtung and / or a change in the preselected number of stitches takes place. As the main shaft position sensor, an incremental encoder, which is used anyway for the motor control, can be used, which is located on the sewing machine main shaft.

Execution game: ·,

The invention will be explained below using an exemplary embodiment. to be purified »Show in the accompanying drawings:

Pig. 1 sewing machine with counting and evaluation control side view '. / · '

Pig. 2 Fähmaschine with counting and Auswertesteuerung front view

15 "Pig. 3 Block diagram of counting and evaluation control

A sewing machine 1, which may be formed as a lockstitch, double-chainstitch or overvolt-end sewing machine, is provided with a fabric edge sensor G3 / 2, a stitch length adjustment device 3, a digital main shaft encoder 4 which has a main shaft position sensor G1 and a stitch count sensor G2, and a counter and counter Ausv / terteuerung 5 equipped.

The counting and Auswertesteuerung 5, which is accommodated in a housing, which is arranged for example in the immediate vicinity of the sewing machine, consists of several sub-circuits.

These sub-circuits are of known type and represent a starting device (gate circuit), two counting chains and two Aus-r value circuits. Each evaluation circuit is connected to a counting chain * The evaluation circuit; which is connected to the counting chain 1, is a classifying device which can select pulses stored in the counting chain 1 at the appropriate moment in one of 4 possible ranges. Depending on which area is activated, the stitch length adjustment device 3 and / or the setpoint value of the second evaluation circuit is subsequently changed. This second evaluation circuit is a

Pulse preselection stage, which, after the set value has been reached by the pulses entering the counting chain 2, initiates the immediate shutdown of the machine via the motor control.

The. Zählkette-, 1 is the input side with the Hauptwellenstellung-. 5 sensor G1 and a Stichahlahlsensor G2 via a starting device in conjunction. While the pulses of the sensor G1 are used for counting up in the Zählkette, 1, the pulses of the sensor G2 constantly lead to clear (reset to the count lull) of the pulses in the Zählkette '1. Since the sensors G1 and G2 are components of the common main shaft encoder 4 and are rigidly coupled and per main shaft rotation of the sensor G1 about 90 ... 120 pulses and the / sensor 'G2 provides a pulse,' it is obvious that the latter repeatedly the Requirement for the crank angle of the sewing machine main shaft proportinale number of pulses by the sensor G1 creates.

The counting chain '2 is the input side with the Stichsahlsensor G2 on the starting device in four bond.

The procedure is now described as follows:

The material to be washed 6 is moved by means of the sewing machine-internal trans- port direction in the device (FIG. 1). The Uähgut 6 covers a reflex point of the example formed as a light barrier fabric edge detection sensor 2 from. If the fabric edge has reached the optical axis 7 of the sensor 2, a signal is generated in the sensor 2, which activates a starting device (Q or orschaltung). The consequence of this is that the pulses previously accumulated in the counting chain 1 are stored by the sensor G1 and the pulses now emitted by the sensor G2 can enter the counting chain 2. The pulses stored in the counting chain 1 are selected in the following evaluation circuit in one of the possible 4 areas, wherein the 4 'said areas correspond to a specific crank angle position of ITähmaschinenhaupt- / wave (3iehe Fig. 3). Is the selection made in the counting chain. 1 accumulated pulses in the. :

Area 1, then the set stitch length by the

Stitching device 3 defined reduced and the set value set. at the pulse preselection level increased by 1 stitch,,. ^v

Area 2, then the set stitch length is defined, increased,. . .-.

Area 3, then the set value ah of the pulse preselection level is increased by 1 stitch,;

Range 4 »then there is no change in the stitch length or the setpoint at the pulse preselection stage.

, If the set value at the impulse precursor is replaced by the

achieved incoming from the sensor G2 in the counting chain 2 pulses, r then takes the immediate machine stop in needle down by a corresponding signal that is triggered by the described evaluation · engine control ... In this way reaches yjird that die'maximale deviation of the last Hadeleinstiches, which is with previously known funds plus / minus 0.5 x stitch length, now with the help of a superimposed stitch length adjustment and stitch number adjustment in the dargestel-Iten way to a maximum plus / minus 0.2 ζ stitch length is improved. Only then is the permissible deviation for the last puncture kept within acceptable limits and the technological applicability of such products considerably increased.

Claims (2)

Bringings ana p ruch 1. Circuit arrangement of an automatic stitch length v and number of stitches for a mower with a .Hähgutkantenerkennungssensor, a digital Haup.t- , shaft encoder and, a counting and Auswertesteuerung "characterized in that a counting and -auswertesteuerung (5) consists of a starter, two counting chains and two Teilauswertesteuerungen, wherein during the sewing constantly incoming to the counting chain 1 pulses of ¹ Hauptwellenstellungssensors G1 stored at the moment of the Uähgutkantenerkennungssensor G3 (2) emitted pulse and classified in the evaluation control in at least 4 areas and this in turn, according to the area, a Stichlängenverstelleinrichtung ^ (3) and / or a change in the preselected number of stitches » 2, circuit arrangement according to item 1, characterized in that is used as a main shaft position sensor G1 for the motor control anyway used incremental encoder, which is arranged on the Hähmaschinenhauptwelle. For this ^ ._ pages drawings