GB2071871A - Knitting machine - Google Patents

Abstract

A knitting machine comprises two pairs of needle beds arranged one after the other, a plurality of knitting carriages arranged to circulate therearound in one direction, a control device co-operable with the knitting carriages for selection of different machine functions, and Jacquard plates, which are selectable according to pattern, mounted in an auxiliary bed and each associated with a respective permanent magnet. For the successive driving, coils (14) associated with the magnets of the Jacquard device as well as with magnets of the control device are disposed in groups and arranged as intersections (13) in a matrix-shaped conductor network with parallel rows (11) and parallel columns (12). A respective electronic switch (16<1>-16<m>, 18<1>-18<n>) is connected with each of the individual rows (11) and columns (12). The row switches (18<1>-18<n>) are connected to receive control signals (MSS<1>-MSS<n>) from a pattern or control function store and are connectible to one pole (+) of a voltage source (17). The column switches (16<1>-16<m>) are connected to receive control signals (S<1>-S<m>) from a multiphase pulse generator and are connectible to the other pole ({) of the voltage source. A respective decoupling diode (15) is associated with each coil (14) to decouple the matrix arrangement. <IMAGE>

Description

SPECIFICATION Knitting machine The present invention concerns a knitting machine.

It is known in an electromechanical Jacquard device in a knitting machine to excite magnets which effect, via mechanical transmission elements, a selection of the needles according to a desired pattern. The driving of each magnet takes place through a switch, in particular an electronic switch. In that case, the magnetic field of all of the magnets excited for a particular pattern, and thereby the current flow, is maintained for a definite time.

This Jacquard device has the disadvantage that the magnets must act for a relatively long time in order to bring the mechanical transmission elements into the desired setting.

Such magnets have a high energy consumption and require considerable space in the knitting machine, this space not always being available.

It is also known in flat circular automatic knitting machines to electromagnetically bring the control device, namely shift cams actuating shift bars of the knitting carriages, into a required setting by way of pushrods, abutments and means controllable through latching magnets and to locate the control device in such setting. Jacquard plates mounted in an auxiliary bed are also actuated electromechanically in that a permanent magnet with coil and pole shoe as well as a tension spring is associated with each of the plates. These Jacquard plates can be brought one after the other into a selection setting according to the desired pattern.In the basic setting of the plates, one foot of each plate lies against the latching surface of the pole shoe of the associated permanent magnet, and in the selection setting of the plates, each plate is pressed by the tension spring against an abutment. This selection setting is achieved by weakening the field of the permanent magnet through its coil so that the tension spring can become effective. This field weakening of the permanent magnet lasts until the selected Jacquard plate has left the range of attraction of the magnet.

Although this device has the advantage that a field weakening of the selected permanent magnets is required for only a short time, a switch is needed for, and a high current consumption takes place in, the actuation of each permanent magnet or each magnet coil.

Moreover, the entire electromagnetic part of the knitting machine involves cost and complication in both manufacture and maintenance.

There is accordingly a need for a knitting machine in which the material and time expenditures in the manufacture of electromagnetic actuating elements of the machine are reduced, while operation and maintenance are simplified and maximum current consumption lowered. In particular, the number of switches required for actuation of such elements should be kept to a minimum.

According to the present invention there is provided a knitting machine comprising two pairs of needle beds, a plurality of knitting carriages arranged to circulate around the needle beds in a given direction, control means comprising magnetic selector means for actuation of means co-operable with the carriages to select different operating functions, and a Jacquard device comprising a plurality of Jacquard cards mounted in an auxiliary bed and magnetic selector means for selecting individual cards in accordance with desired knitting patterns, the selector means of the control means and the Jacquard device comprising a plurality of permanent magnets provided with coils disposed in groups and so arranged in a conductor matrix as to couple together the intersecting parallels of the matrix at the zones of intersection thereof, a respective decoupling device associated with each of the coils, and a plurality of electronic switches each connected to a respective one of the matrix parallels, the switches associated with one of the sets of parallels being connected to be actuable by control signals from operating function or pattern storage means and being connectible to one pole of a voltage source, and the switches associated with the other set of parallels being connected to be actuable by control signals from pulse generating means and being connectible to the other pole of such voltage source.

Preferably, each group of coils of the magnets corresponds to a respective one of the parallels of said other set thereof.

Expediently, a freewheel diode is associated with each switch connected to a parallel of only said one or said other set of parallels, these switches being opened earlier by the freewheel time of the coils. Transistors, thyristors or integrated switching circuits can be used as the electronic switches.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a circuit diagram of a magnet control network for time multiplex control of a Jacquard device or control device in a knitting machine according to the said embodiment, Figure 2 is a detail of an intersection of this network, and Figure 3 is a time diagram for the control of electronic switches of the network.

Referring now to the accompanying drawings, there is shown in Fig. 1 a magnet control network in a flat knitting machine which comprises two pairs of needle beds arranged one after the other, a plurality of knitting carriages circulating therearound in one direction, an electromechanical control device co-operating through shift bars with the knitting carriages for the selection of different machine functions, and a Jacquard device comprising Jacquard plates mounted in an auxiliary bed and selectable electromechanically according to pattern. As the invention is primarily concerned with the afore-mentioned control network, the mechanical components of the machine will not be described in more detail.

The network shown in Fig. 1 is a matrixshaped conductor network formed of rows 11 and columns 1 2. The intersections 1 3 of the rows and columns are formed by the individual coils 14 of permanent magnets of the Jacquard device and the control device. The coils 14, together with associated series-connected decoupling diodes 1 5, form the connections between the rows 11 and columns 12. The coils 14 are arranged in groups corresponding with the columns 12.Electronic switches in the form of transistors 1 61 to 16" are connected to the coils 1 4 of each column 1 2 and to the negative pole of a voltage source 1 7. The transistors 16' to 1 6"', which are connected to a multiphase pulse generator, are switched on one after the other by means of respective signals S1 to S". The signal state 1 on a signal feed line means that the associated one of the transistors 16' to 16" is conductive, while the signal state 0 indicates the blocking thereof. The signals S' to Sm are formed through a digital counter.

Synchronously with the signal states or times predetermined by the signals S' to S" for the transistors 167 to 16", pattern or control signals MSS' to MSS" from a pattern store or stores for control functions (not shown) are supplied, in accordance with a pattern to be generated or a control function to be executed, to further electronic switches, namely transistors 187 to 1 8", connected to each of the rows 11 and to the negative pole of the voltage source. When two signals S and MSS coincide at an intersection 13, the associated coil 1 4 is connected with the positive pole of the voltage source 1 7 for excitation of the magnet concerned.

As can be seen from Figs. 1 and 3, the transistors 1 81 to 1 8n are blocked before the time change for a certain time, namely the freewheel time T of the coils 14, so that the coil current can decay through associated freewheel diodes 194 to 1 9 and the associated, still conductive transistors 16' to 1 6" without generation of a voltage peak. By virtue of the connection of these freewheel diodes 19' to 19~ to the collector of each transistor 18' to 1 8 it is possible to avoid provision of a freewheel diode for each coil 14 at each intersection 1 3. In addition, each of the freewheel diodes 1 91 to 1 9 need be designed only for the current of one coil 1 4.

The actuation of the individual coils 14 after connection of the entire conductor matrix to the voltage source 1 7 proceeds as follows: The columns 1 2 receive the respective signals S' to Sm one after the other through the transistors 1 6t to 1 6", i.e. the transistor 1 61 receives the signal S1, the transistor 1 62 the signal S2.The signals are supplied one after the other to the intersections 1 3, i.e. the coils 14 with the decoupling diodes 1 5. Synchronously with these signals S' to S", signals MSS' to MSS" from the pattern store or the store for control functions are supplied to the intersections 1 3 through the transistors 1 8t to 1 8". When two signals S and MSS meet at an intersection 1 3, the respective coil 14 is excited and the corresponding pattern or control function is initiated.To avoid high voltage peaks, the individual transistors 18' to 1 8" are blocked before the time position change, i.e. before switching off of the conducting transistors 16' to 16", by the freewheel time Tofthecoils 14.

By means of this conductor matrix it is only necessary to provide a switch for each group of coils 14 and for each pattern information signal, instead of for each individual coil 14.

The number of electronic switches required is thus appreciably reduced. Moreover, current consumption can be reduced by this arrangement and a relatively low power voltage source 1 7 is usable. Instead of transistors as electronic switches, it is of course feasible to use thyristors or integrated switching circuits.

In addition, an appropriately programmed control system could serve as the signal generator for the columns 1 2.

Claims (7)

1. A knitting machine comprising two pairs of needle beds, a plurality of knitting carriages arranged to circulate around the needle beds in a given direction, control means comprising magnetic selector means for actuation of means co-operable with the carriages to select different operating functions, and a Jacquard device comprising a plurality of Jacquard cards mounted in an auxiliary bed and magnetic selector means for selecting individual cards in accordance with desired knitting patterns, the selector means of the control means and the Jacquard device comprising a plurality of permanent magnets provided with coils disposed in groups and so arranged in a conductor matrix as to couple together the intersecting parallels of the matrix at the zones of intersection thereof, a respective decoupling device associated with each of the coils, and a plurality of electronic switches each connected to a respective one of the matrix parallels, the switches associated with one of the sets of parallels being connected to be actuable by control signals from operating function or pattern storage means and being connectible to one pole of a voltage source, and the switches associated with the other set or parallels being connected to be actuable by control signals from pulse gener ating means and being connectible to the other pole of such voltage source.

2. A knitting machine as claimed in claim 1, wherein each group of coils is associated with a respective parallel of said other set of parallels.

3. A knitting machine as claimed in either claim 1 or claim 2, comprising a respective freewheel diode associated with and only with each of the switches connected to either said one or said other set of parallels, said switches, in use, being opened by the freewheel time of the coils earlier than the remaining switches.

4. A knitting machine as claimed in any one of claims 1 to 3, wherein the switches comprise transistors.

5. A knitting machine as claimed in any one of claims 1 to 3, wherein the switches comprise thyristors.

6. A knitting machine as claimed in any one of claims 1 to 3, wherein the switches comprise integrated switching circuits.

7. A knitting machine substantially as hereinbefore described with reference to the accompanying drawings.