GB2143640A - Device for comparing distances between objects - Google Patents

Abstract

This invention relates to a device for comparing distances between objects, e.g. balls in a ball game such as bowls and boule. The comparator may be of the "stick" type and may embody a ground contacting box 10 attached by a tube 11 telescopically adjustable to vary the height of a handle 12. The box 10 incorporates, in open ended tubes 8, 9, (Fig. 2, not shown), two transducers 13, 14 which transmit ultrasonic pulses in diametrically opposite directions. The box 10 is rested on the ground between a wood 17 and a jack 18 so as to indicate the distance between them at aperture 19 or in a handle display 20. The two trains of ultrasonic pulses produced by the comparator are reflected back respectively from the jack and the wood. The received pulses provide an indication of the distance apart of the wood and the jack. Reference is made to embodiments employing infra-red pulses or U.H.F. radio transmission pulses. <IMAGE>

Description

SPECIFICATION Device for comparing distances between balls This invention relates to a device for comparing distances between balls in a ball game such as bowls and boule.

In a game such as bowls where the objective is to place a large ball known as a "wood" as close as possible to a small ball, known as a "jack", there is often real difficulty in determining which of two rival woods is closest to the jack. Where visual inspection does not immediately show which is the closest wood it is customary to use a tape measure but this may involved touching the woods or the jack and sometimes a jack or wood is moved, accidentally of course, during the measuring process.

This can lead to some dissention! An object of this invention is to provide a device for comparing distances between balls in a ball game which is accurate and can be used without risk of disturbing the balls.

From one aspect the invention lies in a distance comparator comprising means to transmit two distinct sets of signals in diametrically opposite directions, towards different objects, simultaneously, means to receive reflected signals and means to convert the received signals into an indication of the distance apart of the objects.

The device may be incorporated in a box which may be placed on the ground between the objects, the box having a readout visible in its upper surface and being controlled by a remote control device. Alternatively the device may be at one end of a stick, which may have a handle with controls and read-out devices in the handle.

From another aspect the invention comprises a device for measuring the distance between balls used in a ball game such as bowls or boule comprising a stick-like member incorporating a transmitterireceiver arrangement adapted to send out two sets of signals simultaneously in opposite directions so as to produce an indication of the instance of two balls from each other, In the accompanying drawings: Figure 1 is an isometric view of a bowls distance comparator embodying the present invention; Figure 2 is an isometric view of the lower portion of the comparator shown in Fig.l, a cover being removed to expose the working parts which are shown diagrammatically; Figure 3 is an isometric view of an alternative form of bowls distance comparator embodying the invention; and Figure 4 is a block diagram of the electronic circuit used in the comparator; and Figure 5 shows a third comparator.

The comparator shown in Fig.1 is of the "stick" type and embodies a ground contacting box 10 attached by a tube 11, which may be conveniently about one metre in length and may be telescopically adjustable so as to vary the height of handle 12, and for convenience in carrying.

The box 10 incorporates, in open ended tubes 8, 9 two transducers 13, 14 (see Figs. 1 and 2) which transmit ultrasonic or other pulses in diametrically opposite directions as shown by arrows 15, 16.

As shown in Fig. 1 the box 10 is rested on the ground between a wood 17 and a jack 18 so as to indicate the distance between them.

Two trains of ultrasonic pulses are produced by the comparator, transmitted in diametrically opposite directions by transducers 13, 14 and reflected back respectively from the jack and the wood. The received pulses are interpreted in known manner to provide an indication of the distance apart of the wood and the jack. The information is stored and compared with the distance of other woods from the jack.

The comparator may provide a series of numbers indicating the distances or it may make a comparison between the measured distances and indicate the least distance measured.

The distances may be indicated on the box 10 in the aperture 19 or in a display 20 on the handle.

The handle 12 may incorporate switches operable by rotating the handle so as to switch on and operate the comparator.

The main components are seen in Fig. 2. The transducers 13, 14 are housed in open ended tubes 8 and 9. Above the tubes 8 and 9 is the control circuitry on a series of easily removable printed circuit boards 21. Power is supplied by a battery 22.

Instead of a stick type comparator a box such as box 23 in Fig. 3 may be employed. This incorporates similar tubes 8 and 9 etc. and display 24. It has hinged, foldable, stabiliser plates 25, 26. Stabiliser plates may also be used on the bottom end of the box 10 shown in Fig. 1. The box 23 is connected to a remote control box 24 by a flexible cable 25 and operates in the same vyay as the stick version of Figs. I and 2.

Again the unit is positioned between the wood and the jack to measure their distance apart. It is preferably positioned along the line joining the centres of the bowl and jack to be measured.

The unit emits ultrasonic pulses from electrostatic transudcers towards the bowl and jack alternately and detects the echoes received. The time intervals between the emission and the reception of the pulses are measured and added together to give a digital output proportional to the distance between the bowls.

The resolution of the system is approximately 0.3mm and the display is updated approximately 3 times per second.

The electronic circuit by which this operation is effected is shown in Fig. 4. A stable crystal oscillator 26 together with a frequency divider chain 27 are used to provide the reference for the time interval measurement and to provide the pulses required for determining the sequence of events.

At the start of a sequence, a control unit 28 initiates one of the pulse generators 29 resulting in a short ultrasonic pulse being emitted from the corresponding transducer. At the same time the counter 31 is enabled. The subsequent echo is received by the same transducer 30 and the signal amplified at 32, shaped at 33 and used to disable the counter 31.

The second part of the sequence is identical to the first but applies to the other pulse generator 29A, transducer 30A and amplifier 32A. Hence at this point in the sequence, the number in the counter is proportional to the sum of the two path lengths.

In the last part of the sequence, the number in the counter is stored and displayed and finally the counter is reset. The sequence is repeated continuously.

A comparator circuit may be added to compare the stored numbers from a series of measurements, compare them, and indicate the shortest distance.

Instead of using a numerical indicator of distance a series of coloured lights may light up in turn indicating successive measurements and then the comparator circuit may be operated to select one of the lights and make it flash to indicate the shortest distance.

Instead of using ultrasonic pulses the comparator may, for example, employ infra red pulses or U.H.F. radio transmission pulses.

In Fig. 5 is shown another embodiment of the invention in a compact form. The comparator is housed In a small moulded plastics box 34 which has a pair of diametrically oppositely directed transducers 35 (only one shown) housed in tunnels 36 (only one shown). The box is tapered as shown as and has inset in its top surface 37 a read-out device 38 which may be an electronic digital readout.

The box is preferably about 53/4" (14.61 cms) high, 23/4" (6.99 cms) deep and 31/2" (8.89 cms) wide. The tunnel 36 is located in the lower portion of the box to align with a jack and the tunnel on the opposite side (not shown) may be higher to align with a "wood" as used in bowls.

Claims (11)

1. A distance comparator comprising means to transmit two distinct sets of signals in diametrically opposite directions, towards different objects, simultaneously, means to receive reflected signals and means to convert the received signals into an indication of the distance apart of the objects.

2. A device according to claim 1, incorporated in a box which may be placed on the ground between the objects, the box having a readout visible in its upper surface and being controlled by a remote control device.

3. A device according to claim 1 located at one end of a stick, the stick having a handle with controls andlor read-out devices in the handle.

4. A device for measuring the distance between balls used in a ball game, such as bowls or boule, comprising a stick-like member incorporating a transmitter' receiver arrangement adapted to send out two sets of signals simultaneously in opposite directions so as to produce an indication of the distance of two balls from each other.

5. A device according to any preceding claim and which includes an ultrasonic transmitter or an infra red transmitter or a UHF transmitter, adapted to transmit pulses in opposite directions and to receive returned pulses from both directions and a counter, the counter being started by emission of a pulse and stopped by a corresponding return echo so as to provide an indication of distance.

6. A device according to claim 5 including a comparator circuit to compare stored information from a series of measurements, and to indicate the shortest distance measured.

7. A device according to any preceding claim and including a numerical indicator of distance.

8. A device according to any of claims 1 to 6 and including a series of coloured lights which indicate successive measurements, and means to cause one of the lights to flash to indicate the shortest measured distance.

9. A distance comparator for use in bowls substantially as hereinbefore described and as illustrated in Figure 1 of the accompanying drawings.

10. A distance comparator for use in bowls substantially as hereinbefore described and as illustrated in Figure 2 of the accompanying drawings.

11. A distance comparator according to claim 8 or 9 including an electronic circuit as illustrated in Figure 3.