CS197818B1 - Knitwork density control apparatus for circular knitting machines - Google Patents

Abstract

The system to control the thickness of the fabric produced by a circular knitter has an analogue control to adjust the axial positioning of the needle cylinder. This is formed by a proportional controller with >=2 inputs to provide data through an analogue position indicator for the needle cylinder and a digital/analogue converter. A digital control computer provides the input for the converter through a store. The proportional controller is connected through a store. The proportional controller is connected to the input of a power amplifier, with its output voltage linked through a kinematic chain to a servo-motor connected to the needle cylinder. The use of analogue switching circuits gives a simpler mechanism than a digital switching circuit system, so that a simple position indicator can be used, such as a potentiometer without requiring any additional logic circuits.

Description

BACKGROUND OF THE INVENTION The present invention relates to an electronic device for numerically controlling the density of knitted fabrics produced on circular knitting machines, in particular on small-diameter knitting machines.

Known solutions utilize a digital servo system consisting of an arithmetic unit to electronically control the density of the fabric. This arithmetic unit is generally provided with two inputs for supplying information from a control computer and a digital needle roller position sensor and one output for feeding the resulting information to electronic converters. The converters are used to control the servomotor by means of a speed regulator.

The disadvantage of this device is the complexity of the circuits required to process the digital information from the control computer and the digital encoder. In addition, the digital encoder with the encoded mask must use additional logic circuits to eliminate the indeterminate states that occur when the control segments · These logic circuits further increase the complexity of the entire device.

The device according to the invention aims to overcome these drawbacks of the prior art.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for controlling the density of a fabric on a circular knitting machine

197 818

197 818 a machine which makes it possible to control the density of knitwork formed on each circular knitting machines, or to groups of these machines, a common control center during zabez ^p Ecena ^p l ^y zero changes Hussites ^tre le ^Tů · UKo ^L is ^YR eěen in ^ lation by the ^Y to ^L sectional area, whose principle consists in that, for adjusting the axial position of the stitch density-cylinder is used in the analog control system, which consists of a proportional regulator provided ales ^P on two milliamperes ga ^{py p} ro ^{in AD} ENI information from analog ^é him dreamer. ^p o ^l o ^{hy h} us ^t o ^t o ^s rolls from the digital-analog converter whose input is through the accumulator connected to the digital control computer, wherein the proportional controller is connected to the input of said amplifier, the output of which is conductively connected with a servomotor which is coupled via kinomatic chain with density cylinder of knitting machine.

Further advantages and features of the invention follow from the description of the exemplary embodiment. device wiring and from the attached drawing, where the block wiring diagram of the device is shown ·

Weave density control circuitry consists of two parts, electronic and mechanical ·

The electronic part consists of an accumulator 1, information, a digital-to-analog converter 2, a proportional regulator 6, a power amplifier 4 which drives the servomotor thereof. ·

A DC motor is preferably used as a servomotor for the function according to the invention. However, one pneumatic, hydraulic or stepper motor can be used, provided the power amplifier 6 is converted to the respective converter. For the pneumatic actuator, an electro-pneumatic converter is required. , for hydraulic servomotor electro-hydraulic converter and for stepper motor voltage converter - frequency with phase driver of stepper motor ·

Stratec 1 ⁱ nformation is ^conn Ojen on outputs ^P - r ^ID Measuring ^h o after ^CNTR Pla ye r X · number-metal ^{member and,} for ^EXAMPLE · in the ^f orm ^{of b} The binary ^¹H on ^or an SLA, ^p r: Leo ^D EN to ga třátefo ^P-1 in ^ ormation ^I and is recorded therein ·

The output of information storage 1 is connected to the input of the digital-to-analog converter

2, The output voltage from this digital-to-analog converter is proportional to the digital input. · Proportional controller 2 3® has at least two inputs and one output. · One of the inputs supplies the output voltage from the digital-to-analog converter 2. supply voltage from the output of position sensor 8

· The amplified voltage from the output of the power amplifier £ is applied to the armature of the actuator j> · This actuator represents via the kinematic chain 6 the density cylinder £ · The density cylinder £ is connected to a position sensor_8 · Output voltage from the position sensor 8 is proportional to the axial displacement of the density cylinder £. The density cylinder se is adjusted until the voltage from the resistance sensor JB is equal to the voltage from the digital-analogue

197 818 converter 2, In this situation the difference between the two voltages is zero and the servomotor 2 ^ae -stop * ·

Thus, the density roller X always assumes a position which is given by the numerical data from the control computer - and thus the displacement of the density roller X, and thus the density of the fabric to be formed, also changes.

The density of the fabric to be formed is thus determined only by the digital data programmed in the control counter.

The advantage of the device for controlling the density of the knitted fabric on circular knitting machines is that it is mainly made up of analog circuits which are considerably simpler than the digital circuits suitable for this purpose in order to provide the desired function. Furthermore, only a simple axial displacement transducer formed, for example, by a potentiometer, can be used in this apparatus, as compared to an axial displacement transducer for a numerical control comprising a digital encoder itself, and a number of complex auxiliary logic circuits.

Claims (1)

Device for controlling the density of knitted fabric on circular knitting machines, in particular small diameter, - changing the axial position of the needle cylinder with respect to the casting plane of the retractable sinkers, characterized in that an analog control system is used to adjust the axial position of the density cylinder. consists of a proportional controller (3) ». - provided with at least two vs ^t up ^y for ^{supply, and} day ^and informare of ana ^l o ^g ew ^h o snímafo ^{(8) p} olo ^hy stitch density cylinder (7) and digital - analog - converter (2) whose input is · means A digital control computer (9) is connected to the accumulator (1), the proportional controller (3) being connected to the input of the power amplifier (4) - whose output - is connected via a line to a servomotor (5) coupled via a kinematic chain (6) (7) knitting machines.