GB2059595A

GB2059595A - Measuring distance and speed of bicycle

Info

Publication number: GB2059595A
Application number: GB8029424A
Authority: GB
Original assignee: DANIELS S A
Current assignee: DANIELS S A
Priority date: 1979-09-13
Filing date: 1980-09-11
Publication date: 1981-04-23

Abstract

A method of, and apparatus for measuring the speed of and/or distance travelled by a bicycle (as herein before referred to) in which a transducer is associated with a wheel of the bicycle and produces a signal each time a zone of the wheel passes by the transducer. The signals are used to produce further signal representative of the speed and/or distance travelled by the bicycle and the further signal is displayed in a numeric manner. <IMAGE>

Description

SPECIFICATION Distance and/or speed measurement device This invention relates to a method of, and apparatus for, measuring the speed of and/or distance travelled by a wheeled vehicle. Although this invention is applicable to any type of wheeled vehicle, it is particularly applicable to bicycles, tricycles, motor assisted bicycles, motor scooters and motor cycles. It may be used whatever the size of the wheel, and is, therefore, applicable also to children's bicycles and adult's bicycles with relatively small wheels. Hereinafter, the vehicle will be referred to as a bicycle.

The traditional way of measuring speed of a bicycle is to attach a first gear wheel of approximately to 4 inches diameter to the hub of the front wheel of the bicycle, and to arrange for a second gear wheel to mesh with the first gear wheel. The rotation of the second gear wheel is transmitted by a flexible drive to a dial instrument located on the handlebars of the bicycle. The dial instrument converts the rotation of the flexible drive and produces a dial reading indicative of the speed of the bicycle. An odometer may also be included which indicates the totai distance travelled by the bicycle.

The main disadvantage of such a device is that it consumes a certain amount of energy provided by the user of the bicycle and therefore either the user has to provide extra energy to propel the bicycle at the same speed or the speed of the bicycle is reduced. The tachometer is also cumbersome, the cable in particular being thick and unwieldy.

It is an object of the present invention to provide a method of, and apparatus for, measuring the speed of and/or distance travelled by a bicycle in which the above mentioned disadvantage is overcome.

According to a first aspect of the invention, to determine the speed of and/or distance travelled by a bicycle, on each occasion that a zone of a wheel of the bicycle moves past a transducer mounted on the bicycle an electrical signal is produced by the transducer, said signals are applied to electronic means which produce a further signal representative of the speed and/or distance travelled by the bicycle and said further signal is displayed in a numeric manner.

In one embodiment, the electrical signals from the transducer are counted to produce a count signal from which is derived the further signal.

Thus the zone may be a spoke of the wheel of the bicycle in which case a transducer signal is produced each time a spoke of the wheel moves past the transducer; for a wheel having thirty-six spokes, thirty-six electrical signals are then produced by the transducer for each revolution of the wheel. Alternativeiy a disc may be attached to the wheel of the bicycle, the disc having an array of radial stripes formed on it and the transducer produces an electrical signal each time one of the stripes passes by the transducer.

In a second embodiment, a clock pulse generator produces a train of clock pulses which are counted in each count period initiated and terminated by successive transducer signals. The zone may again be a spoke, but, as the displayed speed accuracy is dependent on the number of pulses counted in a count period the count period can conveniently be associated with one revolution of the wheel. Hence the count period can be controlled by detecting the valve of the tyre or a single stripe on the wheel or any device which can be attached to the wheel to activate the transducer every revolution of the wheel.

According to a second aspect of the invention, apparatus for determining the speed and/or distance travelled by a bicycle comprises a transducer arranged for mounting on the bicycle so as to be asociated with a wheel of the bicycle and for producing an electrical signal each time a zone of the wheel moves past the transducer, electronic means for receiving said transducer signals and deriving a further signal representative of speed and/or distance travelled by the bicycle, and means for displaying the further signal in a numeric manner.

In order that the invention may be more readily understood it will now be described, by way of example only, with reference to the accompanying drawing in which: Figure 1 is a diagrammatic side elevation of a first embodiment of the invention, and Figure 2 is a diagrammatic side elevation of an alternative embodiment of the invention.

In both figures, the front wheel of a bicycle comprises a rim 1, connected to a hub 3 by spokes 5. A tyre 7 is fitted on the rim and the wheel is rotatably mounted in the front forks 9 of the bicycle. In the arrangement shown in Figure 1, a transducer 11 is mounted by means of clips 1 3 on one of the forks 9 at a position between the rim and the hub and close to the rim of the wheel. The transducer 11 comprises a Reed switch 1 5 supported in a support chamber 1 7. A permanent magnet 1 9 is clipped to one of the spokes 5 so that as the wheel rotates with respect to the transducer, the permanent magnet causes the Reed switch to be actuated once each revolution of the wheel.The Reed switch is connected to an electrical circuit which is housed in a casing 21 which is mounted on the handlebars of the bicycle. This casing contains an electric battery 23, electronic circuitry (not shown) and a three digit display 25.

Basically the mode of operation consists of having as part of the electronic circuitry a clock pulse generator producing clock pulses at a fixed frequency, for example 1 ,000 pulses per second and counting the number of pulses generated in a period between successive sensings by the transducer. The count, which is inversely proportional to the speed, is then processed in the electronic circuitry to give a signal which represents the speed and this is displayed on the display 25. The electronic circuitry can also be used to produce a signal representative of the average speed. Furthermore, the circuitry can be used to calculate the distance travelled and all this information can be displayed in turn on the single display by means of changeover switches or buttons.

The detection period should be relatively long for accuracy and is preferably equal to one revolution of the wheel. Each sensing signal generated by the transducer is applied to a counter which in the electronic circuitry receives the clock pulses. The receipt of each sensing signal causes the count in the counter to be read out, the counter to be reset to zero and the count restarted. Each counter readout then represents the number of clock pulses generated between successive sensings and is inversely proportional to the speed during the previous revolution of the wheel.

As an alternative to the magnetic Reed switch system described above, the transducer may operate on other magnetic principles.

Alternatively, the transducer may operate on an optical, inductive, capacitive, acoustic or microwave principle.

In an alternative embodiment of the invention, as shown in Figure 2, the transducer is arranged to produce an electrical signal in the form of a pulse each time one of the spokes 5 passes the transducer. If the wheel is of about 27 inches diameter and has 36 spokes then at 30 miles per hour approximately 220 spokes will pass the transducer 1 1A each second producing about 220 pulses per second from the transducer. If it is not desirable to detect the spokes then an annular disc may be mounted on the hub with a plurality of radially disposed lines or stripes marked on the disc. The stripes may be formed by etching, engraving, printing or the iike and the transducer could operate on a reflective infra-red optoelectronic principle. The transducer produces an electrical signal in the form of a pulse each time a stripe passes by the transducer. Thus, if there are say 200 stripes on the disc then 200 pulses will be produced for each revolution of the wheel. The pulses are applied to the electronic circuitry 21 which includes an LSI chip and the transducer pulses are counted in a set time period of say one second. A signal representing the number of pulses counted in the time period is then modified dependent upon the diameter of the wheel to produce a modified signal which is dependent upon the distance travelled by the wheel in the time period. This modified signal is then applied to a visual numeric display 23 mounted on the handlebars so that it can easily be seen by the user of the bicycle.

In both embodiments of the invention which have been described, the display is conveniently a liquid crystal display since such a display consumes a small amount of power and it is visible even in strong sunlight.

Claims

1. A method of determining the speed of and/or distance travelled by a bicycle (as herein before referred to) wherein on each occasion that a zone of a wheel of the bicycle moves past a transducer mounted on the bicycle an electrical signal is produced by the transducer, said signals are applied to electronic means which produce a further signal representative of the speed and/or the distance travelled by the bicycle and said further signal is displayed in a numeric manner.

2. A method as claimed in Claim 1, in which said electrical signals produced by the transducer in a pre-determined time interval are counted by said electronic means to produce said further signal.

3. A method as claimed in Claim 1, in which said electronic means produces a train of fixed frequency pulses and the number of pulses produced between successive signals from said transducer are counted by said electronic means to produce said further signal.

4. Apparatus for determining the speed of and/or distance travelled by a bicycle (as herein before referred to) comprising a transducer arranged for mounting on the bicycle so as to be associated with a wheel of the bicycle and for producing an electrical signal each time a zone of the wheel moves past the transducer, electronic means for receiving said signals and deriving a further signal representative of the speed and/or distance travelled by the bicycle and means for displaying the further signal in a numeric manner.

5. Apparatus as claimed in Claim 4, in which the transducer is magnetically operated and said zone is provided by a permanent magnet attachable to the wheel of the bicycle.

6. Apparatus as claimed in Claim 4, in which the transducer is arranged to emit a beam of radiation and to produce an electrical signal each time the beam is impinged by said zone.

7. Apparatus as claimed in Claims 4, 5 or 6, in which the electronic means inciudes a counter for counting said signals and for producing said further signal which is representative of the number of signals counted in a predetermined time period.

8. Apparatus as claimed in Claims 4, 5, or 6, in which the electronic means includes a fixed frequency pulse generator and means for counting the number of pulses between successive signals from said transducer and for producing said further signal representative of the count.

9. Apparatus as claimed in Claims 4, 5, 6, 7, or 8, in which the display means comprises a liquid crystal display.

10. Apparatus as claimed in Claim 9, in which the liquid crystal display is capable of selectively displaying a speed display and a distance display.

11. Apparatus for determining the speed of and/or distance travelled by a bicycle substantially as herein before described with reference to the accompanying drawing.