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Title:
BILLIARD CUE HAVING A MULTIPLE TUBE STRUCTURE
Document Type and Number:
WIPO Patent Application WO/2008/155684
Kind Code:
A1
Abstract:
A billiard cue formed of at least two hollow tubes, said cue having a longitudinal axis and a diameter which varies along said axis, first portions (22a) of said tubes farming an outer wall of said cue and defining an interior of said cue characterized in that second portions (22b) of said tubes extend across the interior of said cue and are bonded to one another, at least along much of the length of said cue, thereby to form an internal reinforcing wall.

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WO/1996/009862BILLIARD/POOL CUE
JP2022173976BILLIARD CUE
Inventors:
GAZZARA ROBERTO (IT)
PINAFFO MAURO (IT)
PEZZATO MAURO (IT)
POZZOBON MICHELE (IT)
DAVIS STEPHEN J (US)
Application Number:
PCT/IB2008/052218
Publication Date:
December 24, 2008
Filing Date:
June 05, 2008
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
PRINCE SPORTS INC (US)
GAZZARA ROBERTO (IT)
PINAFFO MAURO (IT)
PEZZATO MAURO (IT)
POZZOBON MICHELE (IT)
DAVIS STEPHEN J (US)
International Classes:
A63D15/08; B29C70/44
Foreign References:
US20030153393A12003-08-14
US4816203A1989-03-28
US20070010340A12007-01-11
US20010046903A12001-11-29
GB2401323A2004-11-10
Attorney, Agent or Firm:
ZANOLI, Enrico et al. (Milano, IT)
Download PDF:
Claims:

CLAIMS

1. A billiard cue (10) having a longitudinal axis (101) characterized in that it comprises at least two hollow tubes (22, 42, 43, 44, 45, 47, 48, 49, 50), first portions (22a) of said tubes forming an outer wall (120) of said cue and defining an interior (121) of said cue, second portions (22b) of said tubes extending across the interior of said cue and being bonded to one another, at least along a portion of their lengths, thereby to form an internal reinforcing wall (24).

2. A billiard cue, according to claim 1, characterized in that said tubes are made of a composite material. 3. A billiard cue, according to one or more of the previous claims, characterized in that said second portions are separated from one another at least at one axial location, so as to form at least one port (20, 201, 202, 51). 4. A billiard cue, according to claim 3, characterized in that it comprises at least one port having a double opposing arch structure. 5. A billiard cue, according to one or more of claims from 3 to 4, characterized in that said second portions are separated from one another at a plurality of selected locations to form a plurality of ports. 6. A billiard cue, according to claim 5, characterized in that it comprises ports which vary in size. 7. A billiard cue, according to one or more of the claims from 5 to 6, characterized in that it comprises ports with different axial orientations.

8. A billiard cue, according to one or more of the previous claims, characterized in that it comprises a metal tube or a wood tube for a portion of its length.

9. A billiard cue, according to one or more of the previous claims, characterized in that at least a portion of said cue comprises a single tube portion (66) joined to a multi-tube portion.

10. A method for manufacturing a billiard cue according to one or more of the previous claims characterized in that it comprises the steps of: providing a plurality of prepreg tubes (60a, 60b), each of said tubes having an inflatable bladder (64) positioned therein; and positioning said prepreg tubes in a mold cavity; pressurizing said inflatable bladders and heating said mold cavity.

11. A method, according to claim 10, characterized in that it comprises also the step of:

positioning one or more pins between said prepreg tubes, said pins maintaining said prepreg tubes separated during the pressurization of said bladders and the heating of said mold cavity, so as to form one or more ports when said prepreg tubes cure.

Description:

BILLIARD CUE HAVING A MULTIPLE TUBE STRUCTURE

DESCRIPTION

The present invention relates to a billiard cue. More particularly, the present invention relates to a billiard cue having a composite structure comprising a plurality of tubes.

The performance of a billiard cue is determined by a number of factors such as weight, bending flex, bending flex distribution, strength, and shock absorption.

Traditional billiard cues are made from wood or laminated wood with a tapered circular cross section. Wood has been the material of choice because of its availability, ease of manufacturing, beauty and feel.

Recently billiard cues have been manufactured of more advanced materials. These cues are typically a single tubular structure with a tapered circular cross section and a hollow interior. The wall thickness can vary along its length to provide specific performance needs. These billiard cues may be made from a number of materials such as aluminum, steel, titanium, and light weight composite materials.

The stiffness and stiffness distribution are also important factors in determining the performance of a billiard cue. The axial stiffness of the cue is the stiffness in compression along the axis of the cue resulting from striking the cue ball on center. The bending stiffness of the cue is the deflection of the cue stick away from the central axis resulting from striking the cue ball off center, for example, when imparting spin to the cue ball.

The weight of a billiard cue is also an important feature in determining performance. The lighter the cue weight, the easier it is to maneuver the cue resulting in higher velocity shots. However, a heavier cue is more stable and will transfer more momentum to the cue ball and can be effective with a slower striking speed. Weight distribution in a billiard cue is also important. If light weight materials are used for the cue structure, then additional weights may be positioned in strategic locations along the length of the cue to enhance stability and feel.

Therefore, the lightest materials and designs are used to achieve these performance goals. The most popular high performance material for modern billiard cue design is carbon fiber reinforced epoxy resin (CFE) because it has the highest strength and stiffness to weight ratio of any realistically affordable material. As a result, CFE can produce a very light weight billiard cue with excellent strength as well as providing a variety of stiffnesses at various regions along the length of the cue.

There are limitations on carbon fiber based materials used for billiard cue structures when considering strength requirements. A billiard cue made from carbon fiber composite can be susceptible to catastrophic failure resulting from excessive compressive forces, which cause buckling of the thin walled tubes. A billiard cue is in fact subjected to a multitude of stress conditions. There are axial impact loads from striking the cue ball and side impact loads resulting from when the cue is dropped or struck on a hard edge. There are bending loads in a multitude of directions. There are also vibrational loads.

Furthermore, there are high stress concentrations where the tip connects to the cue stick. This is an area of high compression loading from impact. In addition, the bending loads are more concentrated in this area because of its proximity to the tip. For this reason, the wall thickness of the cue is generally the greatest in this area.

Another desirable feature in a billiard cue is comfort. Striking the cue ball can produce shock and vibrations which are transmitted to the hands. All types of shock and vibration are magnified with cues of a lighter weight, which don't have the sufficient mass or inertia to absorb the shock or damp the vibrations.

The evolution of the modern billiard cue over the past twenty years has focused on improving light weight, stiffness, strength, and comfort. However, there has not been a billiard cue that has all of the mentioned performance benefits. A stiffer wood billiard cue is shown by U.S. Pat. Application 2007/0078017 to Kwon that describes an improved construction using different orientations of the wood grain structure.

There are numerous examples of fiber reinforced composites used as an option to construct the billiard cue.

Examples are U.S. Pat. No. 6,162,128 to McCarty and Titus; U.S. Pat. No. 6,890,264 to Verona; U.S. Pat. App. No. 2004/0009822 to McCarty; U.S. Pat. App. No. 2006/0247068 to

Lagaipa; and U.S. Pat. App. Nos. 2007/0010340 and 2007/0060406 to Miki.

Specific structural applications using fiber reinforced composites are shown in the following examples.

U.S. Pat. No. 4,943,333 to Chang describes a wood cue drilled with holes followed by a composite material coated on the exterior area of the cue for protection from water and warping. Other examples of using composites for the exterior layer over a wood core include

U.S. Pat. No. 7,746,733 to Yu; U.S. Pat. App. No. 2003/0153393 to Chang; and U.S. Pat.

App. No. 2006/0019761 to Titus.

Other examples of using fiber reinforced composites together with wood include U.S. Pat.

No.7,044,861 to Nally et al.; U.S. Pat. App. No. 2001/0051547 to Takahira; and U.S. Pat.

App. No. 2006/0160633 to Tsai.

U.S. Pat. No. 5,112,046 to Thorpe describes a cue formed of a epoxy resin body with carbon fiber core structure.

Other examples of the majority of the structure comprised of fiber reinforced composites are

U.S. Pat. No.4,816,203 to Tsai; U.S. Pat. No.5,997,970 to You; U.S. Pat. No. 6,110,051 to

McCarty and Titus; and U.S. Pat. No.6,881, 153 to Andrews.

There exists a continuing need for an improved billiard cue that has the combined features of light weight, improved bending stiffness, improved strength, and improved comfort. In this regard, the present invention substantially fulfills this need.

Thus, the present invention provides a billiard cue according to the following claim 1.

In its more general definition, the billiard cue, according to the invention, is made with multiple tubes having portions that are fused together along at least a portion of their lengths to form an internal reinforcing wall.

Preferably, the tubes are separated from one another at selected locations to form apertures that act as double opposing arches, thereby providing improved means of adjusting stiffness, resiliency, strength, and comfort.

Thanks to a design that substantially departs from the conventional concepts, the billiard cue, according to the invention, can provide a combination of light weight, tailored stiffness, greater strength, greater comfort, and improved aesthetics over the current prior art.

The billiard cue, according to the invention, can provide specific stiffness zones at various orientations and locations along the length of the cue, superior strength and fatigue resistance and shock absorption and vibration damping characteristics. The billiard cue, according to the invention, has an improved construction that makes easier to develop a unique look and improved aesthetics.

The billiard cue, according to the invention, has durable and reliable construction, which may be easily and efficiently manufactured at low cost with regard to both materials and labor.

For a better understanding of the invention and its advantages, reference should be made to the accompanying drawings, in which:

Figure 1 is a side view of a billiard cue, according to the invention; and

Figure IA is a cross sectional view of the billiard cue of Figure 1, taken along lines IA- IA; and

Figure IB is a cross sectional view of the billiard cue of Figure 1, taken along lines IB- IB.

Figure 1C is an isometric cut away view of a portion of the billiard cue shown in Figure 1. Figure 2 is a side view of the billiard cue, according to the invention, constructed in accordance with an alternative embodiment of the present invention; and Figure 2A is a longitudinal sectional view of a portion of the billiard cue in Figure 2, taken along lines 2A-2A.

Figure 3 is an isometric view of the billiard cue, according to the invention, which is constructed with a further alternative embodiment; and

Figure 3 A is a cross section of the billiard cue in Figure 3 taken along lines 3A-3A; and Figure 3B is a cross section of the billiard cue in Figure 3 taken along lines 3B-3B; and Figure 3 C is an isometric cutaway view of a portion of the billiard cue shown in Figure 3.

Figure 4 shows an alternative example of how multiple ports could be oriented in a multiple tube construction for the billiard cue, according to the invention; and Figure 4 A is a cross sectional view along the lines 4A-4A of the structure of Figure 4. Figures 5A-5D show various shapes of ports of the billiard cue, according to the invention. Figure 6 shows schematic views of a process for forming the billiard cue, according to the invention.

Figure 7 shows schematic views illustrating a process for forming a billiard cue, according to the invention, which is formed with portions of different materials. Figure 8 shows a cut away view of a portion of the billiard cue, according to the invention. Figure 9 schematically shows a process to form an axially oriented port in the billiard cue, according to the invention.

The same reference numerals refer to the same parts throughout the various figures. The basic structure of the billiard cue, according to the invention, is formed of two or more tubes, which comprises portions that are molded together to form a common wall (or walls, in the case of more than two tubes). This common wall improves the stiffness and strength of the billiard cue by acting as a brace to resist bending loads.

However, at selected locations, the facing surfaces of the tubes are preferably kept apart during molding, to form openings. On either side of the openings, the tubes are joined together. The openings so formed are referred to herein as "ports." As it will be better shown below, these ports are formed without drilling any holes or severing any reinforcement fibers.

The resulting structure is found to have superior performance characteristics for several reasons. The ports are preferably in the shape of double opposing arches which allow the structure to compress axially which deforms the ports, for absorbing shock and damping

vibration, for more comfort and feel.

The structure also has a different bending stiffness depending on the orientation of the center wall and the ports. This provides a cue stick which has different performance characteristics for performing different types of shots. The internal wall between the hollow tubes adds strength to resist compressive buckling loads such as those near the tip of the cue.

Finally, the structure can also facilitate attachment to other portions of the cue stick or to the tip assembly.

Figure 1 illustrates a billiard cue 10 that includes a tip portion 13, a central portion 15 and a handle portion 17. At the end of the tip portion 13 an impact tip 14 is provided. A gripping portion 16 is located within the handle portion 17.

Preferably, the cue 10 has a longitudinal axis 101 and a diameter, which varies along said axis.

The cue 10 is made of a plurality of hollow tubes. In figure IA, two hollow tubes 22, which form the structure of the cue 10 in this embodiment, are shown. The tubes 22 are preferably formed of composite material.

The tubes 22 comprises first portions 22a forming the outer wall 120 of the cue 10 and defining an interior 121 of said cue. The tubes 22 comprise second portions 22b that extend across the interior 121 and are bonded to one another, at least along a portion of their lengths, thereby forming an internal reinforcing wall 24. Basically, the hollow tubes 22 are joined together to form the internal wall 24. The preferred location of the internal wall 24 is near the axis 101 of the cue 10. Both of the hollow tubes 22 should be about the same size and, when molded, form a "D" shape.

Preferably, the billiard cue 10 contains through openings, or "ports" 20, which are oriented in line with axes parallel to each other. In the example of figure 1, the port axes are horizontally oriented, which will provide more flexibility in a horizontal plane, and more stiffness in a vertical plane.

Figure IB shows that, at the locations of the ports 20, the hollow tubes 22 are separated from one another to form the walls 30 defining the ports 20. It is advisable to have a radius (i.e. rounded edges 26) leading into the port 20, so to reduce the stress concentration and to facilitate the molding process.

Figure 1C is an isometric view of the billiard cue 10 isolated to one port 20, which shows the two hollow tubes 22 and the internal wall 24. Also shown is the port 20 formed by the curved wall 30, which may have the shape of a portion of a cylinder. In this particular example, the

axis of the port is substantially at 90° with respect to the axis 101 of the cue 10. Figure 2 shows a partial side view of the cue 10, in which the axes of the ports 20 are vertically oriented, which will provide more flexibility in a vertical plane, and more stiffness in a horizontal plane. Figure 2A shows that, at locations other than the ports, the hollow tubes 22 are positioned side-by-side and are fused together along much of their lengths to form the common wall 24 that extends across the diameter of the cue 10, i.e., it bisects the cue interior 121. At selected locations, e.g., where ports 20 are to be formed, the facing surfaces 30a and 30b of the tubes 22 are separated during molding to form apertures 20a, preferably in the shape of double opposing arches, which act as geometric supports to allow deformation and return. In addition, the internal wall 24 provides structural reinforcement to resist deformations and buckling failures.

Figure 3 shows an alternative embodiment of the billiard cue 10 designed using a multiple tube construction, which allows the forming of ports 201 and 202 oriented at different angles. In this particular example, the ports 201 nearer the tip region 13 of the cue 10 have horizontally oriented axes 103, in order to provide greater vertical plane stiffness in this area. The ports 202 near the handle end have vertically oriented axes 102 in order to provide greater horizontal plane stiffness in this area. Therefore a billiard cue with this type of design would be considered to have a stiffer vertical plane tip region and a more flexible vertical plane handle region. It is also possible to do the opposite or any combination desired.

In the example of Figure 3 A, four tubes 42, 43, 44, 45 are used to create the outer wall 120 of the cue 10 and define the interior 121. The tubes 42-45 form an internal wall 24 in the form of an "X". The Figure 3B cross section is in the region of a port 202. The hollow tubes 42 and 43 have remained together as well as hollow tubes 44 and 45. The tubes 42 and 43 are separated respectively from the tubes 44 and 45 during molding to create the port 202. Figure 3 C is an isometric view of a cutaway portion of the cue 10 of Figure 3 showing a port 201 with a horizontal axe and a port 202 with a vertical axe. As described above in connection with Figures 3A and 3B, the ports 20 may be formed by separating two tubes from the other two tubes. In this example, in order to form the port 201, the hollow tubes 42 and 45 remain together as well as hollow tubes 43 and 44. To form the port 202, the hollow tubes 42 and 43 remain together as well as hollow tubes 44 and 45. Figure 4 is an isometric cutaway view of a four tube structure 52 with ports for all tubes

positioned at a same location. In this example, hollow tubes 47, 48, 49, and 50 are all separated to form four ports 51 therebetween.

Figure 4A is a cross sectional view of the tube structure 52 in Figure 4 taken along the lines 4A-4A. Here it can be seen that because the four hollow tubes 47-50 are separated, there results in an open port 51 that has four openings 51a-d. This particular embodiment would provide more flexibility and resiliency for both in plane and out of plane conditions at a same location.

In the multiple tube design of the cue 10, according to the invention, there can be any number of ports and orientations of ports depending on the number of hollow tubes used and how many are separated to form these ports. In addition, for example with a 3 tube design, the axis of the port would not necessarily have to pass through the center of the cue 10. Figures 5A-5D illustrate some examples of the variety of shapes possible to be used for the ports 20, 201, 202, 51. Depending on the performance required of the structure at a particular location, more decorative port shapes can be used. In all orientations, the quantity, size, and spacing of the ports 20, 201, 202, 51 can vary according to the performance desired. In addition, the internal wall 24 assists in resisting the stress induced by striking the cue on the edge of a pool table or when the cue is dropped on a hard surface. This is an excellent application of where a multiple tube construction such as using 4 tubes therefore creating an X-shaped internal wall 24 (see Figs. 3-4. described above) will better resist the circumferential stress.

According to a preferred embodiment of the present invention, the billiard cue 10 comprises multiple continuous composite tubes, which are arranged to form the ports 20. With respect to the traditional way of designing and manufacturing composite billiard cues, the adoption of multiple tubes allows an improved prediction of the orientation, according to which the billiard cue 10 will produce the desired stiffness. Since the internal wall 24 is aimed at resisting deformation of the cross section under loading, thereby at contrasting the buckling under compressive forces, it is possible to properly customize the billiard cue structure in terms of its stiffness and resiliency, e.g. by varying, in addition to the geometry of the billiard cue itself, the size, number, orientation and spacing of the ports. The process of molding with composite materials facilitates the use of multiple tubes in a structure.

A traditional method of producing a composite billiard cue is to start with a raw material in sheet form known as "prepreg", which are reinforcing fibers impregnated with a thermoset

resin such as epoxy. The resin is in a "B Stage" liquid form, which can be readily cured with the application of heat and pressure. The fibers can be woven like a fabric, or unidirectional, and are of the variety of high performance reinforcement fibers such as carbon, aramid, glass, and the like. The prepreg material commonly comes in a continuous roll or can be drum wound which produces shorter sheet length segments.

The prepreg is cut at various angles to achieve the correct fiber orientation, and these strips are typically overlapped and positioned in a "lay-up", which allows them to be rolled up over a mandrel to form a perform. In order to pressurize and consolidate the prepreg plies, external pressure must be applied. This is commonly done by wrapping a polymer "shrink tape" around the exterior of the preform which will apply pressure upon the application of heat in a curing oven. The mandrel determines the internal geometry of the billiard cue. The thickness of the consolidated laminate plies determines the external geometry of the cue. The present invention will require a different molding technique because the use of multiple tubes and forming ports requires internal pressure to consolidate the prepreg plies.

For example, when molding the same billiard cue using two prepreg tubes 60a, 60b, each tube should be approximately half the size of the cue to be obtained. A polymer bladder 64 is inserted into the middle of each prepreg tube and is used to generate internal pressure to consolidate the plies upon the application of heat. The mold packing process consists of taking each prepreg tube and internal bladder and position into a mold cavity and an air fitting is attached to the bladder 64. Care should be taken for the position of each tube so that the internal wall 24 formed between the tubes is oriented properly, and that pins (not shown) can be inserted between the tubes 60a, 60b in order to form the ports 20 during pressurization. The pins are secured into portions of the mold and are easily removed. The mold is pressed closed in a heated platen press and air pressure for each tube 60a, 60b should be applied simultaneously to retain the size and position of each tube and the formed wall 24 in between. The pins maintain the prepreg tubes separated during the pressurization of the bladders and the heating of the mold cavity. Simultaneously, the tubes 60a, 60b will form around the pins and will form the ports 20 during the curing of said tubes. In fact, as the temperature rises in the mold, the viscosity of the epoxy resin decreases and the tubes expand, pressing against each other until expansion is complete and the epoxy resin is cross linked and cured. The mold is then opened, the pins removed, and the part is removed from the mold. The internal wall 24 of the molded tubular part adds significantly to improving the structural

properties of the tubular part. The internal wall 24 helps resist bending deflections, resulting from striking the cue ball off center, which will improve directional control. In addition, during bending deflection, the shape of the billiard cue 10 is maintained much better, eliminating the tendency to buckle the cross section. The orientation of the wall 24 can be positioned to take advantage of the anisotropy it offers. If more bending flexibility is desired, the wall 24 can be positioned along the neutral axis of bending. If greater stiffness is needed, then the wall can be positioned like an "I Beam" at 90 degrees to the neutral axis to greatly improve the bending stiffness. Molding the tubular parts of the cue 10 using multiple tubes 60a, 60b allows greater design options. Separating the hollow tubes 60a, 60b at selected axial locations along the cue length in order to mold large oval shaped openings 20 between the tubes, allows the characteristics of the billiard cue to be varied as desired.

Molding in of ports 20, at selected locations, results in a double opposing arch construction. What is contributing to the structure, is the "double arch effect" of the ports 20, which are oval in shape creating two opposing arches, which allow the cue to deflect, while retaining the cross sectional shape because of the three dimensional wall structure provided by each port 20. For example, a ported double tube structure has a combination of exterior walls, which are continuous and form the majority of the structure, and of ported walls, which are oriented at an angle to the exterior walls, which provide strut like reinforcement to the cue structure. The cylindrical walls of the ports prevent the cross section of the tube from collapsing, which significantly improves the strength of the structure.

The stiffness and resiliency of the ported double tube structure can be adjusted to be greater or less than a standard single hollow tube. This is because of the option of orienting the internal wall between the tubes as well as the size, shape, angle and location of the ports. The ports 20 can be stiff if desired, or resilient allowing more deflection and recovery, or can be designed using different materials or a lay-up of different fiber angles in order to produce the desired performance characteristics of the structure.

The structure can be further refined by using more than two tubes. For example, using three tubes allows for apertures to occur in 120 degree offsets, providing specific stiffness tailoring along those directions.

Using four tubes provides the possibility of having apertures at ninety degree angles to each other and alternately located along the length of the tubular part to achieve unique performance and aesthetic levels.

Another option is to locate multiple ports 20 in the same location to achieve more of an open truss design.

Another option is to combine a single composite tube with a multiple tube composite design. In this example, the single composite tube can be a portion of the cue stick and co-molded with the multiple tubes to produce a lower cost alternative to a 100 % multiple tube construction. Another option is to combine the composite portion with a metal portion of the cue. In this example, the metal tube can be a portion of the billiard cue and fused or co-molded with the multiple prepreg tubes to produce a lower cost alternative to a 100 % carbon composite construction. This can produce a less expensive structure that can still achieve the performance and aesthetic requirements of the product.

Referring to Figs. 6-7, in order to make this construction, the forward ends 62 of the prepreg tubes 60a, 60b, each having an inflatable bladder 64, are inserted into one end 65 of a metal tube 66. The unit is placed inside a mold having the same shape of the metal tube 66, at least at the juncture 70 of the prepreg tubes 60a, 60b and the metal tube 66. A pin or mold member (not shown) is placed between the prepreg tubes 60a, 60b, where a port 20 is to be formed. The mold is then closed and heated, as the bladders 64 are inflated, so that the prepreg tubes assume the shape of the mold, the mold member keeping the facing walls 71a, 71b apart so as to form the port 20. As shown, the tubes 60a, 60b will form a common wall 24 at seam 72. After the prepreg tubes have cured, the frame member is removed from the mold, and the mold member or pin is removed, leaving the port 20. In this embodiment, the seam 70 between the portions 60a, 60b and the metal tube portion 66 should be flush. The tube portion 66 may also be constructed of wood or plastic.

Yet another option is to construct a billiard cue structure using 100% of metal materials. In this case, a method to produce this structure is to start with a metal tube with a "D" shaped cross section. The tube can then be formed with a half arch bend at least along a portion of its length. A similar operation can be done with another metal tube. The two tube halves can then be attached by fixing the flat sides of the D shaped cross section so that the two half arches oppose each other. The tubes can be welded or bonded together resulting in a structure with an internal reinforcing wall and a double opposing arch shaped aperture. An alternative method to produce a multiple tube structure out of metal is to start with a metal tube such as aluminum, titanium, steel, or magnesium for example, and deform the tube in local areas to create dimples or craters in the surface of the tube on opposing sides. The centers of these dimples can be removed leaving a circular aperture through the tube. A tubular section

can then be positioned through these circular apertures and fixed to the edges of this dimple area of the primary tube using a welding process to create the 3D structure. The result will be a structure with the primary tube being a single hollow tube with other single hollow tubes attached in a transverse manner internal to the primary tube. Basically, there are unlimited combinations of options when considering a ported structure for the cue 10. The ports 20 can vary by shape, size, location, orientation and quantity. The ports 20 can be used to enhance stiffness, resilience, strength, comfort and aesthetics. For example in a low stress region, the size of the port can be very large to maximize its effect and appearance. If more deflection or resilience is desired, the shape of the aperture can be very long and narrow to allow more flexibility.

The ported tube construction of the billiard cue 10 can also provide more comfort to the billiard player. As mentioned previously, the stiffness of the cue 10 can be optimized to provide greater flexibility if desired. An advantage of the invention is the absorption of the shock wave traveling up axis of the cue stick resulting from striking the cue ball. Having ports 20 along the length of the cue 10, which can deform and absorb this force, can increase the contact time on the cue ball which can improve feel, spin and control.

Yet another advantage of the invention is vibration damping. Vibrations are damped more effectively with the opposing double arch construction. This is because the movement and displacement of the arches absorbs energy which damps vibrations. As the cue parts deflect, the shape of the ports 20 can change, allowing a relative movement between the portions of the tube either side of the port. This movement absorbs energy which damps vibrations. If more vibration damping is desired, the ports 20 can be oriented and shaped at a particular angle, and constructed using fibers such as aramid or liquid crystal polymer. As the port deforms as a result of cue stick deflection, its return to shape can be controlled with these viscoelastic materials which will increase vibration damping. Another way to increase vibration damping is to insert an elastomeric material inside the port.

The ports 20 provide a means to add custom weighting in the form of weight plugs. This would allow the user to tune the cue stick to their desired weight and balance. These plugs may also be elastomeric or viscoelastic to provide enhanced vibration damping means. Finally, there is a very distinguished appearance to a billiard cue made according to the invention. The ports 20 are very visible, and give the tubular part a very light weight look, which is important in product marketing. The ports 20 can also be painted a different color, to further enhance the signature look of the technology. The ports 20 may also use designer

shapes to give the product a stronger appeal.

Another advantage of the billiard cue 10, according to the invention, consists in making easier the attachment between parts of the cue itself. Many cue sticks come in 2 or 3 sections, and each attach to the others using a fastening means such as threads. It is possible to mold an "axial port" with an axis in line with the longitudinal axis of the cue as shown in Figure 8. The axial port 80 separates the tubes 22a and 22b. A fastener 82 with a male portion 84 is inserted into the port 80 and secured using an adhesive. The fastener 82 has a cavity 86 on the opposite side with threads to accommodate another threaded fastener. This is only one example of numerous solutions to attach different parts of the cue stick using an axially oriented port 80. The tip assembly 14 may also be attached to the body of the cue 10 in a similar manner.

The method to mold such an axial port is shown in Figure 9, in which a longitudinal sectional view of the end of cue stick 10 is shown. The two prepreg tubes 60a and 60b have internal bladders 64 which are pressurized. The mold cavity is not shown. A pin 90 is located between tubes 60a and 60b to create the axial port 80. When air pressure is applied to bladders 64, the tubes 60a and 60b expand to form the tubes 22a and 22b around the pin 90, which creates the axial port 80. The pin 90 is fixed to the mold and removed following the molding operation.