RU2607432C1 - Second generation billiard cue - Google Patents

Abstract

FIELD: sports.

SUBSTANCE: invention relates to sports equipment for table games, namely billiard cue structure that allows to reduce the deviation of the cue from the aiming line and to increase the accuracy of hitting the desired point. Lighter hollow body of billiard cue has two balance loads at opposite sides, at the same time the initial point of balance can still be maintained. There is a string stretched along the axis of the cue body, one end of the string is fixed to the first load, and the other one is attached to a bumper pad, connected the other end part by a threaded connection, providing control of the string tension.

EFFECT: both balance loads are made from tungsten.

5 cl, 4 dwg

Description

The invention relates to sports equipment for board games, namely to a billiard cue.

Known billiard cue, equipped with a light emitting element located in it, and the shock end of the cue has a hole for the focused beam of the light emitter (RU 46119, class A63D 15/08, published 10.06.2005). A cue with a beam sight and the point of its beam reflected on the ball-cue ball can increase the accuracy of striking the cue ball, but does not exclude the possibility of moving the cue to the side during its movement to the cue ball.

As the closest analogue of the proposed solution, a composite billiard cue is selected, the casing of which includes a drummer, a middle part and a turnstile, while the middle part and the turnstile are connected to each other by means of a threaded fastener made in one piece with a balanced load placed in the cavity of the turnstile, formed from the middle part, and the striker and the end part of the turnstile are made with cavities (RU 2525461, class A63D 15/08, published on 08/20/2014).

The well-known cue with a lightweight striker and turner allows you to reduce the axial moment of inertia, which contributes to less drift of the cue ball when hitting with a screw (not in the center of the ball), as well as increasing the initial angular speed of rotation of the cue ball in side impacts. However, at long and direct impacts, the small axial moment of inertia of such a cue does not allow it to clearly follow the line of sight. The strength of the famous cue is the blows of the side brother-in-law with a strong propeller.

The objective of the invention is to improve the playing qualities of the cue, associated with an increase in the accuracy of long-range strikes and a decrease in the removal of the cue away from the aiming line when striking the cue ball.

The named task is provided with a technical result aimed at increasing the axial moment of inertia of the billiard cue without increasing the weight of the entire structure while providing the possibility of regulating the stiffness of the billiard cue.

The technical result is achieved in the invention using the following combination of features.

The body of the billiard cue is hollow and consists of a drummer, middle part and turnip. A string is stretched along the axial line in the body cavity, and two balanced weights are placed inside the body from opposite sides with the possibility of maintaining the original balance point.

A sticker is fixed at the end of the drummer, with the first balanced load placed in the drum cavity from the side of the sticker and connected to one end of the string.

The turner has a removable end part, in the cavity of which a second balanced load is placed.

The end part of the turnstile by means of a threaded connection is connected with a bumper strip located at its end, which together with this connection and with the other end of the string forms a string tension control unit.

Both balanced loads are made of tungsten.

The reason that affects the withdrawal of a billiard cue from the aiming line to the cue ball at the time of preparation and delivery of a blow is, in particular, the following. Since, when performing a perfectly accurate strike, the cue must move in a plane perpendicular to the surface of the billiard table, the brush compressing the turnstile of the billiard cue should not make transverse oscillatory, circular and curvilinear movements during acceleration of the cue. However, the human musculoskeletal system is not able to perform perfectly parallel-translational movements. In practice, a person carries out a set of swing movements, which together can come close to a parallel-translational movement. Therefore, any deviation from the movement of the hand compressing the shaft of the cue from the vertical plane passing along the line of impact causes an inaccurate hit at the aiming point on the cue ball.

To reduce the withdrawal during acceleration of a billiard cue from its intended trajectory, at least two conditions must be met:

- increase the axial moment of inertia of the entire cue structure;

- increase in his weight.

Increasing the weight of a billiard cue more than three times the weight of a game ball is impractical. The weight characteristics of a billiard cue were examined in detail by A. Coriolis in the final chapter of his book "The mathematical theory of the phenomena of a billiard game." Unlike the weight characteristics and speeds of movement of a billiard cue, its axial moment of inertia was practically not considered in this book.

The technical result associated with an increase in the axial moment of inertia of a billiard cue (see Appendix 1) was achieved in the invention by dividing the balanced weight of the cue into two parts and spacing these parts at different ends of the cue (without changing the balance point). Thus, it is possible to increase the axial moment of inertia of a billiard cue by almost an order of magnitude.

The following is a calculation of the axial moment of inertia of a billiard cue with balanced balance weight.

In classic billiard cue, based on the volume of the wooden workpiece (see Appendix 4), its density and the weight of the used balanced load, the ratio of the weight of the balanced load to the weight of the wooden workpiece is approximately equal to one. In the case of the proposed second-generation cue, in the body of which a cavity is formed along the axial line, the weight of the wood billet is reduced by the amount of seized wood, i.e. about half, and therefore, to comply with the above conditions, the weight of the balanced load should be increased by this value.

The density of wood is 0.5-0.7 g / cm ³ ;

the density of tungsten is 19.3 g / cm ³ ;

; или

от наклейки (см. приложение 4);balance point

; or

from a sticker (see Appendix 4);

- длина кия.Where

- the length of the cue.

между осями:According to the Huygens-Steiner theorem, the moment of inertia of the body J relative to an arbitrary axis is equal to the sum of the moment of inertia of this body Jc relative to the axis passing through the center of mass of the body parallel to the axis under consideration and the product of body mass m by the square of the distance

between axles:

;

;

T.O. the axial moment of inertia of a billiard cue with a hollow body and balanced balance load of tungsten can be 8-10 times greater than the axial moment of a classic cue.

The invention is illustrated by drawings, where in FIG. 1 schematically shows a billiard cue (axial section of a General view); in FIG. 2 - an embodiment of the middle part of the cue (axial section); in FIG. 3 - end part of the turnip; in FIG. 4 - node tension control string (in an enlarged form).

Depicted in FIG. 1 hollow billiard cue 1 contains the following components: a cylindrical drummer 2 made in one piece and a conical middle part 3, as well as a conical turner 4 detachably connected to the middle part, having a removable end part 5. The drummer ends with a sticker 6, under which there is one balanced cargo 7.1.

A second balanced load 7.2 is installed in the cavity of the end part 5 of the turnstile. The end part 5 of the turnstile by means of a threaded fastener 8 is connected with the bumper cover 9.

Both balanced loads 7.1 and 7.2 are made of tungsten, the density of which is two times higher than the density of iron or lead, which also contributes to an increase in the axial moment of inertia while maintaining the relatively small size of the balanced load itself.

Inside the cue cavity along the axial line there is a stretched thin cable or string 10, one end of which is fixed to the first balanced load 7.1, located in the cavity of the drummer, and the other is connected to the tension control unit 11 of this string, which is fixed to the bumper strip 9.

In the cavity of the cue, near the junction of the striker with the middle part of the cue, as well as in the upper part of the turnstile, washers 12 are installed, which help maintain the straightness of the cue. Drummer 2 at the junction with the middle part 3 of the cue may have a slight narrowing in the form of an annular recess 13.

The outer part of the bumper lining 9 is made of elastic soft material.

In FIG. 2 shows an embodiment of the turnstile 4, on the inside of which a recess 14 is formed for connection with the middle part 3 of the billiard cue.

In FIG. 3 shows the end part 5 of the turnstile with the second balanced load 7.2. A hole 15 was made along the axial line in the center of this balanced load, for the passage of the string 10 through it, fixed, in accordance with this option, directly on the bumper trim 9.

The thickness of the string 10 is selected so that the frequency of its oscillations is in the sound frequency range. The player should be able to monitor the state of the billiard cue, as the frequency of oscillations of the stretched string varies depending on the strength of the string tension, temperature and humidity.

In FIG. 4 is an enlarged view of a string tension control unit formed by a threaded fastener connection 8 connecting the end part 5 of the turnstile to the bumper cover 9, while the end of the string 10 is fixed in the socket 16 formed on the inside of the bumper cover 9.

The presence of a stretched string in the billiard cue body, located also in the turner (unlike the closest analogue), allows to reduce the wall thickness of the cue and, therefore, to further reduce the weight of its body without lowering the rigidity of the entire cue structure.

To find the optimal diameter of a hollow projectile, it is necessary to determine the dependence of the stiffness of this projectile on its external and internal diameters. The deflections of the material are inversely proportional to the geometric moment of inertia of its cross section and the Young's modulus of this material. The moment of inertia is directly proportional to the fourth power of the linear dimensions of the material section. (A.V. Aleksandrov et al. “Resistance of materials”, M., Higher School, 2003). Thus, increasing the diameter of the hammer by a quarter and making a groove in it, with a diameter of up to 0.75 of the original size without increasing its mass (see Appendix 2), we get an increase in the rigidity of the hammer by more than 10 percent (see Appendix 3) .

Appendix 1. Consider two identical-looking billiard cues with completely identical sizes (length, diameters of the sticker and the turnstile) made of similar material, of the same weight and having balance at the same point on the turner. These outwardly identical billiard cues can have different values of the axial moment of inertia. The moment of inertia is a measure of the inertia of solids in a rotational motion (just as mass is a measure of inertia in translational motion). With a known body mass, the moment of inertia depends both on the distribution of this mass over the body volume and on the position and direction of the axis of rotation.

- масса i-й точки,

- расстояние от i-й точки до оси.Where:

- mass of the i-th point,

- distance from the i-th point to the axis.

Next, we find the axial moment of inertia of the straight thin rod, when the axis is perpendicular to the rod and passes through the center of mass. We consider a billiard cue as a thin rod. The axis passes through the center of gravity (balance point), in our case, almost through the grip.

Derivation of the formula.

и массой m на малые фрагменты длиной dr. Масса и момент инерции такого фрагмента равна:Break the cue, length

and mass m into small fragments of length dr. The mass and moment of inertia of such a fragment is equal to:

;

;

.

.

Integrating, we get:

.

.

- длина стержня.where: m is the mass of the rod,

- the length of the rod.

;

; S₁-S₂=S₃;

;

; d₃=0,75Appendix 2

;

; S ₁ -S ₂ = S ₃ ;

;

; d ₃ = 0.75

Appendix 3

;

,

;

,

where: D is the diameter of the tip of the drummer;

J _x is the geometric moment of inertia of the rod along the x axis;

J _y is the geometric moment of inertia of the rod along the y axis;

π - number = 3,14.

Appendix 4. Calculation of the volume of the cone:

; где: h - высота конуса; π - число 3.14.

; where: h is the height of the cone; π is the number 3.14.

where: R is the radius of the base of the cone; r is the radius of the base of the cone.

;

Truncated Cone Volume:

;

where: N is the height of the truncated cone; R is the radius of the lower base of the cone; r is the radius of the base at the top of the truncated cone; h is the height of the cone without truncation.

Volume of hollow truncated cone:

Claims (5)

1. Billiard cue, the body of which is hollow and consists of a drummer, middle part and turnstile, while a string is pulled along the center line in the body cavity, and two balanced weights are placed inside the body from opposite sides. 2. Cue according to claim 1, characterized in that a sticker is fixed to the end of the drummer, while the first balanced load is placed in the drum cavity from the side of the sticker and connected to one end of the string. 3. Cue according to claim 2, characterized in that the turnstile has a removable end part, by means of a threaded connection connected to a bumper strip located at its end, which forms, together with this connection and the other end of the string, a string tension control unit. 4. Cue according to claim 3, characterized in that a second balanced load is placed in the cavity of the end part of the turnstile. 5. Cue according to claim 1, characterized in that both balanced loads are made of tungsten.

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