Patent Application
20080070724
The upper portion 14 is intended to form a support for a golf ball. To this end, the upper portion 14 includes an axially upper most and radially outward rim or edge 18 defined on a first annular member 20 that receives the golf ball, not shown. The upper portion 14 also includes a second annular member 22 affixed to a second end of the shaft 12. A set of three trusses or support members 24 are connected to each of the first annular member 20 and the second annular member 22 to provide support to the first annular member 20.
This type of Tee construction is less likely to fracture while being struck by a golf club, which is often the case with Tees of other materials such as wood and of other plastic designs. Both the trussed design and the choice of soft material for the upper portion enhance the ability of the Tee so survive impact by a golf club.
In the embodiment of
The support members 24 generally incline upward an outward from the second annular member 22 to the bottom and the generally inner annular wall 28 of the lower annular portion 26 of the first annular member. The support members 24 are spaced apart around the circumference of the second annular member 22, forming through-holes 25 or openings in upper portion 20. In some embodiments, the support members 24 may extend continuously around circumference of the tee 10 such that the first annular member 20, the second annular member 22, and the support member 24 forms a solid, continuous surface. However, inclusion of at least one interruption, through-hole or other type of void is advantageous in many embodiments because it increases flexibility and/or reduces material costs, while retaining structural integrity. The use of voids such as through-holes may also provide relief from non-uniform stress in the upper portion 14.
In general, the upper portion 14 as described above, and/or in other embodiments, comprises a unitary structure of a second moldable material which is different from the first moldable material of the shaft 12. The use of two different moldable materials provides for different advantages in different embodiments, but generally allows for the versatility of using molded parts (as opposed to carved or cut wood), and the versatility provided by using different materials and/or injection steps for the two parts of the tee that serve different functions.
In some embodiments, the upper portion 14 and the shaft 12 are connected by bonds formed at the interface therebetween. The interface between the upper portion 14 and the shaft 12 lies at the upper end of the shaft and the inner surface of the second annular portion 22. The bond connection may suitably be formed by molding the upper portion 14 onto the shaft 12, as discussed below in connection with
In some embodiments, the second moldable material of the upper portion 14 is relatively flexible such that it elastically deforms relatively easily to the touch. In such embodiments, the upper portion 14 may flex and deform upon impact of the golf club, not shown, on the golf ball placed on the tee 10. To this end, in some embodiments, the second moldable material is more flexible than the first flexible material, and may suitably be primarily thermoplastic elastomer, urethane or silicone.
Flexibility of the upper portion 14 can in some cases provide various advantages, such as improved ball release. In addition, some elastically deformable materials such as GLS Dynaflex have a slightly tacky quality that may enhance golf ball spin during flight. No one of these particular advantages is critical to all embodiments of the invention. At least some of the advantages of using a unitarily formed upper portion of a second moldable material that is more flexible than the first moldable material of the shaft may be obtained even if the upper portion and shaft are not overmolded or connected by bond.
As discussed above, the “trussed” design of the upper portion 14 of the tee 10 formed by the through-holes 25 may enhance the flight characteristics of the golf ball, as there is less structural resistance because of the voids, as there would be in a solid tee. This is particularly true if the upper portion 14 is flexible. Moreover, by using a soft or lower durometer material for the upper portion 14, the upper portion 14 is also less likely to damage the face of gold clubs.
In still other embodiments, the first moldable material and the second moldable material may be structurally similar, but differ in color. In such a case, the upper portion 14 would be a first color and the shaft 12 would be a second color. This embodiment may be used to economically provide tees having color schemes corresponding to or symbolizing a school, club, nation or other collective group.
In this exemplary method, the tees are formed in a two-material overmolding process, wherein the upper portion 14 is formed in one station of the mold, and the shaft 12 is formed in another station. In the exemplary embodiment described herein, the shaft 12 is formed in a first operation and the upper portion 14 is overmolded onto the shaft 12. In this embodiment, the two materials used bond chemically to each other.
Referring now to
The core side 104 includes two substantially identical core stations 118 and 120. the core stations 118 and 120 are arranged on a rotatable mount 122. Each of the core stations has a core assembly 124. Each core assembly 124 includes structures that define the interior surfaces of the through-holes 25 of the upper portion 14 and the inverse of the support members 24. The core assemblies 124 also include a center post 126 that defines a hollow central cavity of the shaft 12.
In operation, the first station 106 of the cavity side 102 cooperates with one of the core stations 118, 120 to form the shafts (12) of four tees (10), while the second station 108 of the cavity side 102 cooperates with the other of the core stations 118, 120 to form the upper portions (14) on top of previously molded shafts (12). These operations occur concurrently. Thus, for a particular tee, the shaft 12 is first molded, extracted from the first cavity 110, then inserted into a cavity 112 of the second station 108. In the cavity 112, the upper portion 14 is molded onto the shaft 12. Thereafter, the finished tee is ejected.
To accomplish the foregoing, the rotatable core side 104 is positioned such that the core station 118 is generally aligned with and facing the first station 106 of the cavity side 102, and more specifically, such that the cavities 110 are aligned with the core assemblies 124 of the core station 118. In this position, the core assemblies 124 of the core station 120 are similarly aligned with the cavities 112 of the second station 108. The core assemblies 124 of the core station 120 have completed shafts (2) from a previous molding step formed thereon.
The core side 104 is then moved toward the cavity side 102 such that they abut each other, at which point the center posts 126 of the core assemblies 124 are inserted into the cavities 110, and the center posts 126 and molded shafts are inserted into the cavities 112. With specific reference to the first station 106, each core assembly 124 and its respective cavity 10 exactly defines the inverse of hollow shaft 12. Molten material is injected into each cavity 110 and allowed to solidify thermally. In the embodiment described herein, the molten matter may be cooled via water cooled metallic mold materials transferring heat from the polymers. The result is a newly molded shaft 12.
With specific reference to the second station 108, each core assembly 124 and respective cavity 112 defines, along with an upper portion of the shaft 12, the inverse of the upper portion 14. It is noted that upper portion of the shaft 12 forms a part of the “core” that defines the inner surface of the second annular member 22 of the upper portion 14. Otherwise, structures of the core assembly 124 and the cavity 112 define the remaining structures of the upper portion 14. Molten material is similarly injected into each cavity 112 and allowed to solidify. The temperature of the second molten material must be at a temperature that actuates bonding of the two materials, but does not degrade the previously injected material. By way of non-limiting example, if the shaft 12 is polypropylene, and the upper portion 14 is thermoplastic elastomer (“TPE”), then the temperature of the molten TPE may suitably be 400° F.
The materials and temperature in one embodiment are selected such that a bond is formed at the interface between the upper portion 14 and the shaft 12. However, in an alternative embodiment, the shaft 12 and upper portion 14 may be selected to having mechanical retention (i.e. interlocking) elements. However, mechanical retention elements can significantly increase the complexity of the mold as they typically require undercuts.
Thus, after the above described molding step, the first station 106 generates four shafts of four tees on the core assemblies 124 of the core station 118 and the second station 108 generates four upper portions overmolded onto four previously formed shafts. As a result, the core assemblies 124 of the core station 120 contain completed tees.
After this molding step, the rotating core side 104 is moved axially away from the cavity side 102, and the four completed tees on core station 120 are ejected from the core assemblies 124 of the core station. The rotating core side 104 then rotates such that now-empty core assemblies 124 of the core station 120 are aligned with the cavities 110 of the first station 106, and that the shaft-bearing core assemblies 124 of the core station 118 are aligned with the cavities 112 of the second station 108. So aligned, the rotating core side 104 is moved axially toward the cavity side 102 and the above molding operations are repeated with the new rotational position of the core side 104.
These operations are repeated such that two molding steps are required for each tee 10, and such that four tees are generated for each molding step. The exemplary method described above eliminates assembly operations, automated or manual, which increase cost and complexity, without removing the advantages of using different moldable materials for the shaft 12 and upper portion 14 of the tee.
It will be appreciated that the above describe embodiments are merely exemplary, and that those of ordinary skill in the art may readily devise their own modifications and implementations that incorporate the principles of the present invention and fall within the spirit and scope thereof. For example, it will be noted that the ball receiving portion of the upper portion 14 need not include a continuous rim 18, but may instead consist of a series of structures forming an interrupted, but generally level, annulus or periphery. For example, the continuous rim 18 may be replaced by a circularly arranged series of posts, bumps or other support structures. Moreover, while the ball receiving structure of the upper portion is preferably circular in shape as shown in
It will also be appreciated that the benefits of the two material construction are more fully apparent when the shaft constitutes a majority of the tee, because it provides a rigid support. Even when support is not an issue, the use of a longer shaft than upper portion allows the tee to retain a more traditional appearance, and will therefore allow for wider acceptance in the golf audience. The longer shaft also facilitates additional flexibility in the height at which the ball is teed up. Thus, in at least some advantageous embodiments, the length (i.e. height) of upper portion 14 is less than one-half, and preferably less than one-third, of the length of the shaft 12.
