GB2152390A

GB2152390A - Aiming device for a table ball game

Info

Publication number: GB2152390A
Application number: GB08400490A
Authority: GB
Inventors: John David Waterhouse
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-01-10
Filing date: 1984-01-10
Publication date: 1985-08-07
Also published as: GB8400490D0

Abstract

An aiming device for gauging the direction of aim of a cue ball in a table ball game to direct the object ball in a desired direction comprises a plate 12 having scale markings diverging from a centre in the manner of a protractor. The plate is radiused at one edge to assist in positioning said centre at a predetermined distance from the centre of the object ball with said centre and the centre of the object ball lying on the desired direction of movement of the object ball after impact. The predetermined distance is equal to the sum of the radii of the two balls. The diverging scale markings are calibrated such that the marking pointing at the centre of the cue ball provides an indication of a linear distance from the centre of the object ball at which the cue ball should be aimed. A pointer 14 is provided for aiming at the centre of the cue ball and alignment with an appropriate one of said markings. <IMAGE>

Description

SPECIFICATION Aiming device for a table ball game The present invention relates to an aiming device for a table ball game, such as snooker, billiards, pool or bar billiards, to assist the player to gauge the position at which to aim the cue ball in order to direct the object ball in a desired direction after impact.

A problem when learning the game of snooker is the gauging of the position at which to aim the cue ball in order to pot the object ball, that is to say a red ball or one of the colours. The cause of the difficulty is that the position to aim at is not only dependent upon the desired angle of deflection but also upon the distance of the cue ball from the object ball. The reason for this is that after impact, the direction of movement of the object ball coincides with the line joining the centres of the two balls at the time of impact. It is therefore necessary when aiming the cue ball to judge the desired position at the time of impact, this being a position independent of the position of the cue ball and offset from the centre of the object ball. Because of the offset, the angle of aim of the cue ball is clearly dependent upon its distance from the object ball.

For this reason, the art of playing snooker has been regarded as one acquired from experience alone, which makes learning the game more difficult since a new player while perfecting his aiming technique is not sure of where he should be aiming, with the result that one is never sure if the aiming or the technique is at fault.

The present invention seeks to provide a measuring instrument to assist in gauging the correct position at which to aim.

According to the present invention, there is provided an aiming device for gauging the direction of aim of a cue ball in a table ball game to direct the object ball in a desired direction, the device comprising a plate having scale markings diverging from a centre in the manner of a protractor, means for positioning the centre of the plate at a predetermined distance from the centre of the object ball with the centre of the object ball and the centre of the plate lying on the desired direction of movement of the object ball after impact, the said predetermined distance being equal to the sum of the radii of the two balls, and the diverging scale markings being calibrated such that the marking pointing at the centre of the cue ball provides an indication of a linear distance from the centre of the object ball at which the cue ball should be aimed.

Preferably, the distance is displayed on the scale as a fraction of the diameter of the ball.

Conveniently, a pointer is pivoted at the centre of the plate for aiming at the object ball, the scale markings being read from the point on the scale beneath the pointer.

To position the centre of the plate at the correct distance, the edge of the plate nearer the object ball may conveniently be formed as an arc of appropriate radius to be centred by the player about the object ball. The shape of the arc and its position from the centre of the plate depend upon the size of the balls and if it should be required to make the device universal then adaptor piates may be provided for different sizes of balls. In such an embodiment, representing the aiming position as a fraction of ball diameter or radius is particularly convenient since the scale will apply to all ball sizes.

It is possible to use the plate with it lying flat on the surface of the table or even hand held but it is easier to centre the plate if it lies on a raised pedestal at height above the table equal to the radius of the balls. When the plate is provided with adaptors for balls of different size, then it is convenient to shape the adaptors such that each sits in a plane offset from the plane of the scale at the appropriate height above the table for the size of ball.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram to illustrate the method of using the aiming device of the invention, Figure 2 is a plan view of an aiming device, and Figure 3 illustrates the imaginary lines relative to centre of a ball at which aim should be made, the lines corresponding to the different scale markings on the device in Figure 2.

Referring first to Figure 1, if the object ball 10 is to move along the direction 15 after impact, then the cue ball 16 at the point of impact should lie with its centre on the line 15. In order to assertain where to aim, the aiming device of the invention is positioned with its centre at the desired position of the cue ball 16 at the point of impact and aligned such that its centre line points in the direction of the line 15.

The device 12, as shown in Figure 2, comprises a plate 12 and a pointer 14 which is pivotable as indicated by an arrow 17 about the centre of the scale markings. Each of the scale markings corresponds to one of the lines shown schematically in Figure 3.

The lines in Figure 3 are imaginary, but when viewing the ball it is possible to gauge their positions because they are spaced apart by equal distances, their separation being equal to one eighth of the radius.

After the device has been positioned as described above relative to the object ball, the pointer 14 is rotated about the scale until it points at the centre of the cue ball 16. The scale markings can now be read off and the appropriate one of the lines aimed at in order to deflect the object ball in the direction of the pocket.

In order to position the aiming device with accuracy, the lower edge of the plate 12 as viewed in plan Figure 2 has an arc which is to be concentric with the object ball 10. This can be estimated in practice by ensuring that an even space exists between the object ball 10 and the edge of the plate 12. When so aligned the plate will be accurately positioned with its centre at a distance from the centre of the object ball 10 equal to the sum of the radii of the object ball and the cue ball.

In order to allow the same plate to be used with different sized balls, the arcuate edge may be formed as part of a separable template which is assembled to the lower face of the plate 12 by alignment pins (not shown).

The plate 12 preferably is located on a pedestal or feet so as to sit at such a height above the table that its arcuate edge lies at a height equal to the radius of the ball. This helps to reduce any errors caused by parallax. In order to accommodate different size balls, the templates mounted on the plate 12 may have variable sized spacers so that templates intended for smaller balls lie nearer the plane of the table.

The positions of the scale markings along the edge of the plate 12 are such that when the device is positioned at the correct distance from the object ball, the line connecting each scale marking to the centre is exactly tangential to a circle centred on the object ball and having a radius equal to the scale marking multiplied by one eighth of the radius of the object ball in the case of the embodiment illustrated.

It will be appreciated that the number of the scale markings may be varied. That is to say, the aiming range from the straight ball to the maximum cut may be subdivided into a different number of parts but sixteen divisions are believed to be optimum since any greater number cannot readily be visualised while a smaller number will result in a reduction in the accuracy of aiming.

It will also be clear that whereas the centring of an arc on the ball is deemed the most convenient method of aligning the aiming device in use, other configurations, such as a rectangular or a triangular cut-out, may be used instead to assist in the alignment.

Claims

1. An aiming device for gauging the direction of aim of a cue ball in a table ball game to direct the object ball in a desired direction, the device comprising a plate having scale markings diverging from a centre in the manner of a protractor, means for positioning the centre of the plate at a predetermined distance from the centre of the object ball with the centre of the object ball and the centre of the plate lying on the desired direction of movement of the object ball after impact, the said predetermined distance being equal to the sum of the radii of the two balls, and the diverging scale markings being calibrated such that the marking pointing at the centre of the cue ball provides an indication of a linear distance from the centre of the object ball at which the cue ball should be aimed.

2. An aiming device as claimed in claim 1, wherein the distance is displayed on the scale as a fraction of the diameter of the ball.

3. An aiming device as claimed in claim 1 or 2, wherein a pointer is pivoted at the centre of the plate for aiming at the object ball, the scale markings being read from the point on the scale beneath the pointer.

4. An aiming device as claimed in any preceding claim, wherein in order to position the centre of the plate at the correct distance, the edge of the plate nearer the object ball is formed as an arc of appropriate radius to be centred by the player about the object ball.

5. An aiming device as claimed in any preceding claim, wherein the plate is supported on a raised pedestal at height above the table equal to the radius of the balls.

6. An aiming device constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.