NZ208422A - Ultrasonic ranging caliper for bowls - Google Patents

Description

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Publication Datz: .... ^.1$??.... P.O. Journal No: ...\SQ.2? NEW ZEALAND No.: Date: PATENTS ACT, 1953 COMPLETE SPECIFICATION DEVICE FOR COMPARING DISTANCES BETWEEN BALLS r~ ^0/ MARTIN STUART THOMPSON ^ nK ' v hereby declare the invention fox which I / «re pray that a patent may be granted to jme/jis, and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 (followed by page -la-) — tCH- DEVICE FOR COMPARING DISTANCES BETWEEN BALLS 208422 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 5 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 ^71) 10 customary to use a tape measure but this may involve 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 ^ 15 for comparing distances between balls in a ball game which is accurate and can be used without risk of disturbing the balls.

The present invention broadly consists in a portable distance comparator comprising a first transducer operable to transmit a first set of ■ ultrasonic signals in a first substantially horizontal direction towards a first object, a second transducer positioned vertically above the first transducer and operable to transmit a second set of ultrasonic signals in a second direction diametrically opposite to said first direction towards a second object, signal interpreting means operable to receive from each object reflected ultrasonic signals emanating from each transducer and connected to display means;, operable to display visually information indicative of the distance between the two objects.

The device may be incorporated in a box which may be placed on the ground between the objects, the box having said display means in the form of a read-out visible in its upper surface and being controlled by a 30 remote control device. Alternatively, the device may be ■?y 208422 at one end of a stick, which may have a handle with controls and display means jn handle. m In the accompanying drawings Fig.1 is an isometric view of a bowls distance 15 comparator em' dying the present invention; Fig.2 is an isometric view of the lower portion of the comparator shown in Fig.1, a cover being removed to expose the-working parts which are shown diagramma-tically; Fig.3 is an isometric view of an alternative form of bowls distance comparator embodying the invention; Fig.4 is a block diagram of the electronic circuit used in the comparator; and Fig.5 shows a third comparator. 25 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 30 carrying.

^ E N V 2 ONOVIwd * m . c ^ C Si 208422 The box 10 incorporates, in open ended tubes 8,9, two transducers 13, 14 (see Figs.1 and 2) which transmit ultrasonic pulses in 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 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 2 ONOVI987, ft* \ * 208422 •^v hinged foldable, stabiliser plates 25. 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 24A by a flexible cable 25A and operates in 5 the same way as the stick version of Figs.1 and 2.

Again, the unit is positioned between the wood and the jack to measure their distances apart. It is (J preferably positioned along the line joining the centres of the wood and jack to be measured.

The unit emits ultrasonic pulses from electro static transducers towards the wood and jack alternately and detects the echoes received. The time intervals between the emission and reception of the pulses are measured and added together to give a digital output 15 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 20 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 measurememt 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 30. At the same time the counter 31 is enabled. The subsequent echo is received by the same 30 transducer 30 and the signal amplified at 32, shaped in X "V : ''Y' 208422 • ( < ■'N pulse shaper 33A arid used to disable the counter 31.

The second part of the sequence is identical to the first but applied to the other pulse generator 29A, transducer 30A and amplified 32A. Hence at this point in 5 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. 10 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 15 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.

In Fig.5 is shown another embodiment of the invention in a compact form. The comparator is housed in a small 20 moulded plastics box 34 which has a pair of oppositely directed transducers 35 (only one shown) housed in tunnels 36 (only one shown). The box is tapered as shown and has inset in its top surface 37 a read-out device 38 which may be an electronic digital read-out. 25 The box is preferably about 51" (14.61 cms) high, 21" (6.99cms) deep and 3i" (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 30 bowls.

Claims (10)

208422 G WHAT 1/2SFB- CLAIM IS: r%r » TUP i • i J , n I Mb>

1. A portable distance comparator comprising a first transducer operable to transmit a first set of ultrasonic signals in a first substantially horizontal direction towards a first object, a second transducer positioned vertically above the first transducer and operable to transmit a second set of ultrasonic signals in a second direction diametrically opposite to said first direction towards a second object, signal interpreting means operable to receive from each object reflected ultrasonic signals emanating from each transducer and connected to display means operable t.o display visually information indicative of the distance between the two objects.

2. A comparator according to Claim 1 , incorporated in a box which may be placed on the ground between the objects, and in which the display means comprises a read-out display visible in its upper surface, the comparator being controlled by a remote control device.

3. A comparator according to Claim 1 located at one end of a stick, the stick having a handle in which ) controls and/or the display means are located.

4. A comparator according to any preceding Claim and which includes an ultrasonic transmitter to transmit pulses to both transducers and to receive VlEA»/\ % © | 2 0N0V1987 v* ~T 308422 returned pulses from both transducers and a counter, the counter being started by emission of a pulse and stopped by a corresponding return echo.

5. A comparator according to Claim 4 including an electrical circuit operable to compare stored information from a series of measurements, and to indicate the shortest distance measured.

6. A comparator according to any preceding claim in which the display means includes a numerical indicator of distance.

7. A comparator according to any one of Claims 1 to 5 in which said display means includes 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.

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

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

10. A distance comparator according to Claim 7 or 8 includi " ' " ustrated in Figure 4.