WO2003023731A1

WO2003023731A1 - A contact-less data transmission system for rotating machinery

Info

Publication number: WO2003023731A1
Application number: PCT/GB2002/004087
Authority: WO
Inventors: Halil Hassan
Original assignee: Halil Hassan
Priority date: 2001-09-12
Filing date: 2002-09-10
Publication date: 2003-03-20
Also published as: GB2381075B; GB2381075A; GB0122029D0; GB0220943D0

Abstract

The invention consists in a contact-less data transmission system for rotating machinery which is capable of transferring data from the inside to the outside of the machine, or vice versa. The transmission is effected through two sets of electrical barriers (6, 7-8, 9) and comprises two sets of brush assemblies which use concentric differential capacitive electrodes (51, 52) without requiring any electrical contact with parts of the machine. In a preferred form of the invention, the differential drive and receive are achieved by a pair of concentric conductive plates printed on insulator using printed circuit board (pcb) technology. The differential capacitive coupling system of the invention has a very wide bandwidth, it being possible to transmit up to three channels of information simultaneously in both directions, and no matching or turning being required.

Description

A CONTACT-LESS DATA TRANSMISSION SYSTEM FOR ROTATING

MACHINERY

This invention relates to a contact-less data transmission system for rotating machinery, and is particularly concerned with the transmission of data from the rotating part of the machinery to the non-rotating part thereof by non- contact means, ie by means of capacitive techniques. Specifically, my invention achieves the transmission of data or information to the outside world, from sensors, whether digital or analogue, or a measuring device relating a rotating part of a twinning machine to a stationary part thereof, the brush assemblies of the state of the art being omitted.

A conventional twinning machine twists a plurality of insulated or non- insulated wires to form a cable. The twist length of the cable is predetermined, and is controlled by controlling the tension with which the wires are twisted to form the cable and the rotational speed of the wire feed drum. The data which are to be transmitted, eg the signals described above and various other signals used for sensing, for example, temperature, limit switches and so on, go at present through two sets of slipring and brush assemblies, ie two sets of electrical barriers.

In the context of this invention, an "electrical barrier" corresponds to an electrical interface between two mechanical assemblies, where one part of a machine rotates around another part of the machine at the interface, an electrical connection being there made using a standard electrical brush assembly.

In accordance with my invention, I have sought to replace the sets of brush assemblies associated with a twinning machine in the prior art, in order to reduce maintenance cost and time and to increase the yield of the twinning machine.

Systems involving data transmission with a single electrical barrier using optical, capacitive and inductive techniques have already been proposed in the art to which my invention relates. Some of these systems such as inductive and optical systems can only transmit single channel but in two directions. An inductive system can only handle one electrical barrier and an optical system can only function in a clean environment. So far as I can determine, the most pertinent of these prior art proposals appears to be Reschovsky and Hunt US-A-4,242,666. This uses capacitive coupling in the same way as the present invention. More specifically, Reschovsky and Hunt use a single electrode and their system is designed for a single electrical barrier. In a single electrode system such as that of Reschovsky and Hunt, the return path of the signal system relies on the integrity of the electrical connection between the rotating and non-rotating parts of the machine to which the system is applied, and therefore requires electrical continuity as between the mechanical parts.

In contrast, my invention uses two differential concentric plates and does not require electrical continuity throughout the system. The bandwidth of the capacitive system of my invention is also very much larger than is the case with the inductive system of US-A-4,242,666, enabling more than one channel to be transmitted in both directions simultaneously.

My invention, therefore, consists in a contact-less data transmission system for rotating machinery capable of transferring data from the inside of the machine to the outside thereof, or vice versa, through two sets of electrical barriers, said data transmission system comprising two sets of brush assemblies which use concentric differential capacitive electrodes, without requiring any electrical contact between any of the parts of the machine.

As can be seen from the definition just above, the system of my invention is a capacitive coupling system which is materially distinguished from any of the prior art proposals including what appears at present to be the closest art, namely, the system defined and described in Reschovsky and Hunt US-A- 4,242,666. Thus, for example, unlike any of the prior proposals, including that of Reschovsky and Hunt just referred to, the system of the invention is a two electrical barrier system in which the sets of brush assemblies of the prior art have been omitted. As can be seen from a perusal thereof, the system defined in US-A-4,242,666 is also a capacitive coupling system, but is designed to go through a single electrical barrier, the system comprising transducers which are constituted by metal plates. In contrast, the system of my invention does not rely on a return path through a mechanical chassis but transmits signals in differential signal form. Unlike the system of Reschovsky and Hunt, the system of the invention does not suffer from common mode noise, and the immunity from any other form of noise is very much improved because of the differential drive and detection. As will be further explained below, the differential drive and receive are achieved by means of a pair of concentric conductive plates printed on insulator using printed circuit board (pcb) technology. It will be readily understood by the skilled person in the art to which my invention relates that the use of pcb technology is very much cheaper, easier and more practical in manufacture and installation than is the case with the mechanical plate systems of the prior art. As also mentioned above, unlike an inductive system, the differential capacitive coupling system of the invention has a very wide bandwidth, it being possible to transmit up to three channels of information simultaneously in both directions, and no matching or tuning being required.

In summary, therefore, the system of the invention is characterized by being both a two electrical barrier system and a differential capacitive coupling system. In a preferred form of the invention, the system comprises transducers which are made by the use of pcb technology. According to a further preferred feature of the invention, the electrodes of the transducers are constituted by a pair of concentric plates printed on a pcb. A further feature of the invention is that the system of the invention is capable of transmitting more than one independent channel simultaneously in both directions.

According to a feature of the present invention as described above, instead of steel plates being used, pcb technology is used to make the electrodes of the differential capacitor cheaply and accurately, and, according to a further feature, the differential capacitor is constituted by a pair of concentric cylinders, as shown in the accompanying drawings to which further reference is made below.

By a twinning machine is meant, in the context of the present invention, a twisting machine, bunchers, Datacom twinners, twinners, group twinners, grouping machines, bow twinners, double/triple twist twinners, triple twist twinners, double twist twinners, back twist twinners, back twist machines, triple twist machines, double twist machines, high speed group twinners, double twist stranding machines or tension controlled pay-off machines.

For a better understanding of the invention, reference is now made to the accompanying drawings, in which:

Fig.1 is a schematic block diagram of a conventional transmission system (Rototell TM) for a twinning machine; Fig.2 illustrates part of the transmission system of Fig.1 ;

Fig.3 shows one embodiment of a transmission system according to the invention;

Fig.5 shows, on an enlarged scale, a detail of the prior art transmission system of Fig.2; and

Fig.6 shows, also on an enlarged scale a corresponding detail of the system ofFig.3.

The transmission system shown in Fig.1 comprises three electrically isolated areas, each enclosed on the diagram by a broken line and labelled media 1 , media 2 and media 3, respectively, media 1 and media 2 being Transmit and Receive units, respectively, and media 3 therebetween being a transmission media.

Media 1 (the Transmit Unit) comprises an Input/Rs232, Encoders 1, 2, with a characteristic of 50khz and 5-60V, Signal Conditioners between the Encoders and an interface, links being provided between the connections from the Encoders to the interface via the signal conditioners and connections Dig9 and DiglO to the Input/Rs232. Input/Rs232has six analogue inputs: Anl-An6 and ten digital inputs: Digl-DiglO.

Media 2 (the Receive Unit) also comprises an interface connected to an Rs232 and is additionally connected to two encoders (1 and 2), with a characteristic of 50khz and 0-5V, through Signal Conditioners.

Media 3 (the Transmission Media) is connected between Media 1 and Media 2, respectively.

Fig.2 shows, schematically, the general positioning of transducers and transmitter and receiver boxes in a transmission system according to the prior art for use with a conventional twinning machine. As can be seen from Fig.5 the prior art transmission system of Fig.2 comprises junction boxes 41 and 42 and brush assemblies 38 and 39 which allow signals to be transmitted between the junction boxes 41 and 42. Each of the brush assemblies 38 and 39 comprises from six to eight sets of brushes. The brush assembly contains three power brushes which rotate a bow assembly 33 (see Figs 2 & 5) around a shaft 37. The other power brushes are used for tension measuring encoder speed signals and various other sensor signals, including the DC power supply for the electronic devices.

Figs 3 and 6 illustrate the data transmission system according to the invention. Fig 3 shows, in block diagram form, a system capable of transmitting through two barriers using a differential capacitive technique.

The block diagram of Fig 3 comprises once again 3 blocks labelled Media 1, Media 2, Media 3, the last mentioned being interposed between the other two. Media 1 and Media 2, and are both Rx/Tx Units, the left-hand block (Media 1) relating to a stationary mechanical assembly and the right-hand block (Media 2) relating to a rocking drum assembly area. The left-hand Rx/Tx unit shows three input signals: siglin, sig2in and sig3in feeding into units 1, 2 and 3, respectively, which are themselves connected to a Modulator 4 and a mixer 5, and three output signals: sig4out, sig5out and sig6out connected to units 11-13 respectively, to which a demodulator 10 is also connected. The right-hand Rx/Tx unit has three input signals: sig4in, sig5in and sig6in connected to a mixer 5 through units 1-3, respectively. A Modulator 4 is also connected to the units 1-3. A demodulator 10 is connected to units 11-13, with output signals: siglout-sig3out, respectively.

Media 3 is a rotating transmission media having capacitive differential transducers 6, 7 and 8, 9 (see Fig.6).

As can be seen from the drawings, there are important distinctions between the system of the invention as shown in Figs 3 & 6 and the prior art system shown in Figs 2 & 5, respectively. Thus, in the system of the present invention, the signal brushes of the prior art are omitted, only the power brushes which are used to run the bow being retained. It is to be noted that power brushes usually last much longer than signal brushes.

Furthermore, the junction boxes 41 and 42 of Fig 5 are replaced by Rx/Tx units 34, 35 and the brush assemblies 38, 39 are replced by transducers 6-9, respectively (see Figs 3 and 6).

The Rx/Tx unit 34 of Fig.3 receives signals 1, 2, 3, and so on, from the inside of the bow of the twinning machine, modulates the signals, mixes them and then uses the differential transducers 6 and 7 to transmit information to the outside of the bow. The distance between the plates of the transducers 6, 7 and 8, 9 shown in Fig 6 is in the range of 0.5mm to 1mm. The electrodes of the transducers 6-9, shown at 51 and 52 in Fig.6, are produced by printed circuit board (pcb) technology on suitable insulator material.

The invention described above has various advantageous features which are as follows. The system transmits through two electrical barriers and a single electrical barrier the signals which are required from the bow area to outside the bow area of the twinning machine and vice versa. Furthermore, the system of the invention is able to transmit one or more channels of information simultaneously in both directions, each channel being completely independent of each other channel. A feature of the invention is the use of a differential capacitive plate coupling system, and a further feature of a preferred form of the invention is that the electrodes are printed on non-conductive plate using conventional printed circuit board (pcb) technology. A still further feature and advantage of the invention is that the system can transmit lay length or twist length information without the use of brushes. Particular advantages of the use of the transmission system of the invention in a twinning machine are an increase in reliability, a reduction in maintenance costs and an increase in yield.

Claims

1. A contact-less data transmission system for rotating machinery capable of transferring data from the inside of the machine to the outside, or vice versa through two sets of electrical barriers, said data transmission system comprising two sets of brush assemblies which use concentric differential capacitive electrodes, without requiring any electrical contact with any parts of the machine.

2. A system according to claim 1, in which the bandwidth of the capacitive electrodes is sufficiently large to allow more than one channel to be transmitted in both directions simultaneously.

3. A system according to claim 2, in which the bandwidth of the capacitive system is sufficiently large as to enable the transmission of up to three channels of information simultaneously in both directions, no matching or tuning being required.

4. A system according to any of claims 1 to 3, which has the characteristic of comprising two electrical barriers and of operating without the signal brushes of the prior art, only the power brushes used to run the bow assembly being retained.

5. A system according to any of claims 1 to 4, which transmits signals in differential signal form, whereby the system avoids reliance on a return path through a mechanical chassis.

6. A system according to claim 5, in which a differential drive and receive are achieved by means of a pair of concentric conductor plates printed on insulator, using printed circuit board (pcb) technology.