GB1585175A

GB1585175A - Measurement apparatus for use with a rotary member

Info

Publication number: GB1585175A
Application number: GB29098/76A
Authority: GB
Original assignee: Talbot Motor Co Ltd
Current assignee: Peugeot Motor Co PLC
Priority date: 1977-07-13
Filing date: 1977-07-13
Publication date: 1981-02-25

Description

(54) IMPROVEMENTS IN OR RELATING TO MEASUREMENT APPARATUS FOR USE WITH A ROTARY MEMBER (71) We, TALBOT MOTOR COMPANY LIMITED formerly known as CHRYSLER UNITED KINGDOM LIMITED, a British Company, of Bowater House, 68 Knightsbridge, London, SW1X 7LH, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to measurement apparatus for use with rotary members.

In the field of mechanical engineering, it is frequently necessary to make accurate measurements of variables, for example strain and temperature in rotating members.

Measurements of strain can be obtained by the use of a number of strain gauges mounted on the rotating member and energised from a low level electrical power source through a voltage regulator and thence through appropriate electronic circuits to a frequency signal transmitting arrangement for conversion by a receiver unit to visual display.

In one such known measuring apparatus the rotating member mounted elements associated with the strain gauges are in modular form and comprise a power supply module in which are a number of dry cell batteries, a voltage regulation module, an electronic circuit module and a telemetry transmitter module from which frequency signals are transmitted via an aerial mounted on the rotating member to a receiver unit for conversion into visual display.

The dry cell batteries providing the power source are essentially small and therefore of limited life such that tests of a prolonged nature are generally interrupted due to thte necessity of changing the batteries, furthermore when subjected to relatively high rotational speeds the batteries can break down with a consequent loss of measuring data.

Tests of the kind referred to usually preclude the use of wired connections to a separate source of electrical power supply and an alternative method utilising a slipring connection is not practical where the rotating member undergoing test is subject to oscillating as well as rotational movement; as for example a vehicle propellor drive shaft. This method is in any case undesirable due to slip ring noise interfering with the signal level.

The invention provides a measurement apparatus for use with a rotary member comprising an electrically energisable telemeter for mounting on the rotary member and for making the required measurement having means to transmit a radio signal in accordance with the measurement, a source of visible light or infra-red radiation to be mounted separate from the rotary member but adjacent thereto to direct visible light or infra-red radiation onto the rotary member, and, for mounting on the rotary member, means connected to the telemeter for converting visible light or infra-red radiation received from the source into an electric current to energise the telemeter.

Preferably the means to convert visible light or infra-red radiation into electric current comprise photo-voltaic cells or solar cells for energising by the visible light or infra-red radiation source.

The source may comprise a tungsten filament lamp or lamps to direct light on to the photo-voltaic or solar cells to energise the cells.

In any of the above arrangements at least one annular bank of cells may be provided for mounting on the rotary member.

More specifically two side-by-side annular banks of cells may be provided for mounting on the rotary member.

In any of thet above arrangements where cells are provided a wiper arm may be provided for mounting adjacent the rotary member having a cleaning surface for engaging the cells as they rotate past the wiper arm.

In any of the above arrangements where telemeter may comprise an electrically energised transducer for performing the required measurement, a first amplifier for amplifying the output from the transducer, a voltage-to-frequency converter connected to the first amplifier and a second amplifier and radio-transmitter connected to the voltage-to-frequency converter to transmit a radio signal in accordance with the output from the voltage-to-frequency converter.

In one specific arrangement the telemeter may be arranged to measure strain in the rotary member.

In the case where the telemeter includes a transducer, the transducer for measuring strain may comprise a strain gauge bridge.

In a further specific-arrangement, the telemeter may be arranged to measure temperature.

The following is a description of one specific embodiment of the invention, reference being made to the accompanying drawings in which: Figure 1 is a perspective view of a rotary shaft having strain measuring apparatus thereon; and Figure 2 is a diagrammatic view of the electric circuit of the components mounted on the rotary member in Figure 1.

Tlne apparatus shown in Figure 1 comprises a rotatable shaft 10 on which four strain gauges 11 (only two of which are shown) are mounted. The strain gauges are connected to electronic modules 12 for responding to variation in strain in the gauges. The modules 12 are connected to a voltage regulator module 13 which also includes a power storage means in the form of a capacitor. The voltage regulator is in turn, connected to a telemetry transmitter module 14 from which radio frequency signals are transinitted via an aerial mounted on the rotating member to a receiver unit for conversion into a visual display in accordance with the strain measured by the gauges 11.

The measuring apparatus is energised by a bank of photo-voltaic cells 15 mounted on a base encircling the shaft 10 and are connected to the voltage regulator module 13. The cells are energised by a stationary source of visible light or infra-red radiation which may be in the form of a standard tungsten filament lamp 16 or an infra-red lamp mounted adjacent to the rotating shaft. More than one light source may be provided, in which case the light sources are circumferentially spaced around the rotating shaft to provide an even spread of light shining on the cells.

Under certain test conditions, for example in a foul atmosphere, a flexible wiping arm 17 may be provided having a wiping face 18 for engaging the cell faces to maintain them in a clean condition.

Referring now to Figure 2 of the drawings, there is shown an electric circuit including the components mounted on the rotary shaft 10. The strain gauges 11 are mounted in a conventional strain gauge bridge form 20 which is energised through input leads 21, 22 connected to the photo cells 15 through the voltage regulator 13.

The bridge has output leads 23, 24 which connect the output from the bridge to a first voltage amplifier 25 forming the aforesaid electronic module 12. The amplifier 25 is energised through leads 26, 27 connected to the cells 15 through the voltage regulator 13. The amplifier output has a connection 28 to a voltage-to-frequency converter 29 forming one part of the telemetry transmitter module 14 and the latter is energised through leads 30, 31 connected to the cells 15 through the voltage regulator 13. The amplifier output has a connection 28 to a voltage-to-frequency converter 29 forming one part of the telemetry transmitter module 14 and the latter is energised through leads 30, 31 connected to the cells 15 through the voltage regulator.

The voltage-to-frequency converter output has a connection 32 to a second power amplifier/radio transmitter 33 forming the second part of the telemetry transmitter module which is energised through leads 34, 35 again connected to the cells 15 through the voltage regulator. The radio transmitter of the device 33 has an output aerial 36 for transmitting a signal which is determined by the output from the strain gauge bridge 20.

It will be understood that many modifications may be made to the above described embodiment without departing from the scope of the invention. For example, the strain gauge bridge may be replaced by a transducer capable of measuring temperature and providing an output signal in accordance with the temperature measured. Solar cells may be used in place of the cells 15 provided on the shaft and a source or sources of infra-red radiation may be used to energise the cells.

WHAT WE CLAIM IS: 1. A measurement apparatus for use with a rotary member comprising an electrically energisable telemeter for mounting on the rotary member and for making the required measurement having means to transmit a radio signal in accordance with the measurement, a source of visible light or infra-red radiation to be mounted separate from the rotary member but adjacent thereto to direct visible light or infra-red radiation onto the rotary member, and, for mounting on the rotary member, means connected to the telemeter for converting visible light or infra-red radiation received from the source into an

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. required measurement, a first amplifier for amplifying the output from the transducer, a voltage-to-frequency converter connected to the first amplifier and a second amplifier and radio-transmitter connected to the voltage-to-frequency converter to transmit a radio signal in accordance with the output from the voltage-to-frequency converter. In one specific arrangement the telemeter may be arranged to measure strain in the rotary member. In the case where the telemeter includes a transducer, the transducer for measuring strain may comprise a strain gauge bridge. In a further specific-arrangement, the telemeter may be arranged to measure temperature. The following is a description of one specific embodiment of the invention, reference being made to the accompanying drawings in which: Figure 1 is a perspective view of a rotary shaft having strain measuring apparatus thereon; and Figure 2 is a diagrammatic view of the electric circuit of the components mounted on the rotary member in Figure 1. Tlne apparatus shown in Figure 1 comprises a rotatable shaft 10 on which four strain gauges 11 (only two of which are shown) are mounted. The strain gauges are connected to electronic modules 12 for responding to variation in strain in the gauges. The modules 12 are connected to a voltage regulator module 13 which also includes a power storage means in the form of a capacitor. The voltage regulator is in turn, connected to a telemetry transmitter module 14 from which radio frequency signals are transinitted via an aerial mounted on the rotating member to a receiver unit for conversion into a visual display in accordance with the strain measured by the gauges 11. The measuring apparatus is energised by a bank of photo-voltaic cells 15 mounted on a base encircling the shaft 10 and are connected to the voltage regulator module 13. The cells are energised by a stationary source of visible light or infra-red radiation which may be in the form of a standard tungsten filament lamp 16 or an infra-red lamp mounted adjacent to the rotating shaft. More than one light source may be provided, in which case the light sources are circumferentially spaced around the rotating shaft to provide an even spread of light shining on the cells. Under certain test conditions, for example in a foul atmosphere, a flexible wiping arm 17 may be provided having a wiping face 18 for engaging the cell faces to maintain them in a clean condition. Referring now to Figure 2 of the drawings, there is shown an electric circuit including the components mounted on the rotary shaft 10. The strain gauges 11 are mounted in a conventional strain gauge bridge form 20 which is energised through input leads 21, 22 connected to the photo cells 15 through the voltage regulator 13. The bridge has output leads 23, 24 which connect the output from the bridge to a first voltage amplifier 25 forming the aforesaid electronic module 12. The amplifier 25 is energised through leads 26, 27 connected to the cells 15 through the voltage regulator 13. The amplifier output has a connection 28 to a voltage-to-frequency converter 29 forming one part of the telemetry transmitter module 14 and the latter is energised through leads 30, 31 connected to the cells 15 through the voltage regulator 13. The amplifier output has a connection 28 to a voltage-to-frequency converter 29 forming one part of the telemetry transmitter module 14 and the latter is energised through leads 30, 31 connected to the cells 15 through the voltage regulator. The voltage-to-frequency converter output has a connection 32 to a second power amplifier/radio transmitter 33 forming the second part of the telemetry transmitter module which is energised through leads 34, 35 again connected to the cells 15 through the voltage regulator. The radio transmitter of the device 33 has an output aerial 36 for transmitting a signal which is determined by the output from the strain gauge bridge 20. It will be understood that many modifications may be made to the above described embodiment without departing from the scope of the invention. For example, the strain gauge bridge may be replaced by a transducer capable of measuring temperature and providing an output signal in accordance with the temperature measured. Solar cells may be used in place of the cells 15 provided on the shaft and a source or sources of infra-red radiation may be used to energise the cells. WHAT WE CLAIM IS:

1. A measurement apparatus for use with a rotary member comprising an electrically energisable telemeter for mounting on the rotary member and for making the required measurement having means to transmit a radio signal in accordance with the measurement, a source of visible light or infra-red radiation to be mounted separate from the rotary member but adjacent thereto to direct visible light or infra-red radiation onto the rotary member, and, for mounting on the rotary member, means connected to the telemeter for converting visible light or infra-red radiation received from the source into an

electric current to energise the telemeter.

2. A measurement apparatus as claimed in claim 1 wherein the means to convert visible light or infra-red radiation into electric current comprise photo-voltaic cells or solar cells for energising by the visible light or infra-red radiation source.

3. A measurement apparatus as claimed in claim 2 wherein the source comprises a tungsten filament lamp or lamps to direct light on to the photo-voltaic or solar cells to energise the cells.

4. A measurement apparatus as claimed in any of the preceding claims wherein at least one annular bank of cells is provided for mounting on the rotary member.

5. A measurement apparatus as claimed in claim 4 wherein two side-by-side annular banks of cells are provided for mounting on the rotary member.

6. A measurement apparatus as claimed in any of claims 2 to 5 wherein a wiper arm is provided for mounting adjacent the rotary member having a cleaning surface for engaging the cells as they rotate past the wiper arm.

7. A measurement apparatus as claimed in any of the preceding claims wherein the telemeter comprises an electrically energised transducer for performing the required measurement, a first amplifier for amplifying the output from the transducer a voltage-to-frequency converted connected to the first amplifier and a second amplifier and radio transmitter connected to the voltage-to-frequency converter to transmit a radio signal in accordance with the output from the voltage-to-frequency converter.

8. A measurement apparatus as claimed in any of the preceding claims wherein the telemeter is arranged to measure strain in the rotary member.

9. A measurement apparatus as claimed in claim 8 as dependent on Claim 7 wherein the transducer for measuring strain comprises a strain gauge bridge.

10. A measurement apparatus as claimed in any of claims 1 to 7 wherein the telemeter is arranged to measure temperature.

11. A measurement apparatus for measuring strain in a rotary member substantially as described, with reference to and as illustrated in the accompany drawings.