Patent Application
20080096680
The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:
The present invention is directed to a synthetic bowling pin and method of manufacturing. In one aspect of the invention, the bowling pin of the invention is a bowling pin of synthetic material which complies with accepted tolerances for height, diameter at various locations, weight, center of gravity, and coefficient of restitution. Furthermore, the bowling pin of the invention possesses a pleasing visual appearance, sound, and action, and is cost efficient for the proprietor. The purchase price may be significantly higher but a longer life span will result in a savings to the proprietor.
In another aspect of the invention, a removable base attachment for a bowling pin is provided. The removable feature of the base attachment reduces operating costs by allowing replacement of individual parts instead of the entire pin. In a further aspect of the invention, a method of manufacture of a synthetic bowling pin is provided. The method allows for the relatively quick and simple manufacture of bowling pins that meet conventional requirements.
The bowling pin of the present invention may have any desired external size and shape. However, referring to
For example, the regulation bowling pin, when standing upright, has an overall height of approximately 15 inches with a tolerance of plus or minus 0.031 inches. At a height of approximately ¾ inches, the regulation bowling pin has a diameter of approximately 2.828 inches. At a height of approximately 2 and ¼ inches, it has a diameter of approximately 3.906 inches. At a height of approximately 3 and ⅜ inches, it has a diameter of approximately 4.510 inches. At a height of approximately 4 and ½ inches, it has a diameter of approximately 4.766 inches. At a height of approximately 5 and ⅞ inches, it has a diameter of approximately 4.563 inches. At a height of approximately 7 and ¼ inches, it has a diameter of approximately 3.703 inches. At a height of approximately 8 and ⅝ inches, it has a diameter of approximately 2.472 inches. At a height of approximately 9 and ⅜ inches, it has a diameter of approximately 1.965 inches. At a height of approximately 10 inches, it has a diameter of approximately 1.797 inches. At a height of approximately 10 and ⅞ inches, it has a diameter of approximately 1.870 inches. At a height of approximately 11 and ¾ inches, it has a diameter of approximately 2.094 inches. At a height of approximately 12 and ⅝ inches, it has a diameter of approximately 2.406 inches. At a height of approximately 13 and ½ inches, it has a diameter of approximately 2.547 inches. Each of the diameters has a tolerance of ± about 0.031 inches. Furthermore, the regulation bowling pin weighs at least approximately 3.375 pounds and not more than approximately 3.625 pounds. Even further, the regulation bowling pin has a center of gravity at a height of between approximately 5.625 inches and approximately 5.937 inches.
Referring to
As shown in
In embodiments, the hollow area 15 has a generally conical shape with a sidewall that has a generally constant gradient along a majority of the length of the hollow area 15. For example, the hollow area 15 may have a diameter of approximately 1.6 inches at the bottom of the base 13, and maintain a roughly constant diameter of about 1.6 inches for a length of approximately 0.75 inches inward from the bottom to a first transition 17. The hollow area 15 extends from the first transition 17 to a termination point 19 inside the body 3. In embodiments, the termination point 19 has a diameter of approximately 0.625 inches. The hollow area 15 preferably has a length of approximately 14 inches.
In a preferred embodiment of the neck insert 20′ shown in
As described above, the size and shape of the neck insert will affect the characteristics of the pin. Therefore, the dimensions of the features of the neck insert may be varied for the purpose of adjusting the characteristics of the pin to achieve a desired combination of characteristics. For example, the shoulders may be rounded. Additionally, a lock-in device other than the annular grooves (such as, for example, a protruding rib or other equivalents) may be employed. Or, if grooves are used, the size, shape, and location of the grooves may be varied to achieve desired results.
In
In embodiments, the body is formed around the neck insert 20, as described in greater detail below. As such, the shape of portions of the hollow area 15 will substantially correspond to the shape of portions of the neck insert 20. Accordingly, the shape of the hollow area 15 as described above and hereafter may be varied in order to accommodate the optional neck insert 20 (if the neck insert is used).
In embodiments, the hollow area 15 has a generally conical shape and maintains a generally constant sidewall gradient between the first transition 17 and the second transition 21, the second transition 21 and the third transition 23, and the third transition 23 and the termination point 19. The length of the hollow area 15 between the bottom and the termination point 19 is approximately 14.000 inches.
According to the invention, the mass distribution of the pin is determined by a combination of factors including at least the volume and shape of the hollow area, the volume and shape of the body, and the mass density of the material used to form the body. Thus, to achieve a desired weight, balance, and center of gravity, the hollow area may take different shapes. For example, although the hollow area 15 is described above as preferably having a length of approximately 14.0 inches, it may alternatively have a length in the range of approximately 4.0 inches to 14.0 inches. Also, it is contemplated that the diameter of the hollow area 15 at any location may vary from the values described above in order to achieve a desired weight and balance of the bowling pin.
The bowling pin of the present invention may be composed of any suitable synthetic material. Preferably, the body 3 comprises a unitary piece of homogenous synthetic material. That is, the head, neck, ball line portion, and base are integrally formed of the same synthetic material. In embodiments, the material is a thermoplastic resin and more specifically, the material is ethylene-methacrylic acid (EMAA) copolymer in which the methacrylic acid groups have been partially neutralized with sodium, magnesium ions, zinc or lithium ions. Such a material is sold under the name “SURLYN”™, which is a registered trademark of DUPONT™,
The bowling pin of the invention may comprise a base attachment 5 as shown in
The base attachment 5 of the present invention may be composed of any suitable synthetic material, and preferably comprises nylon or urethane. Moreover, the base attachment 5 may be any suitable size. In embodiments, it has an outer diameter of approximately 2.05 inches at its base. The base attachment 5 further includes an axial bore that is substantially cylindrical and has a diameter of approximately 1.625 inches. In embodiments, the base attachment 5 has a height of approximately 1 inch and can be attached within the hollow area 15 by screw threads or friction fit or other attaching mechanism known to those of skill in the art. Additionally, the base attachment 5 may be designed such that a unique tool is required for its insertion and removal from the body 3.
As described above, the characteristics of the various components (e.g., body, hollow area, neck insert, base attachment) of the pin affect the characteristics of the entire pin. As such, the characteristics of any or all of the components may be varied to achieve desired characteristics of the pin. For example, any combination of the following parameters may be varied to achieve a desired overall bowling pin: body size, body shape, body mass, hollow area shape, location of hollow area, neck insert size, neck insert shape, neck insert location, neck insert mass, base attachment size, base attachment shape, base attachment location, base attachment mass.
The mandrel of the instant invention is not limited to the shape and design shown in
Step 810 may optionally include installation of a neck insert inside the mold cavity. In embodiments, a portion of a neck insert is connected to a portion of the mandrel that is to be disposed within the mold cavity. The connection may be accomplished in any manner that allows the mandrel to be pulled away from the neck insert when material that forms the pin body is introduced around the neck insert. For example, the neck insert may be connected to the mandrel by friction fit of the extension of the neck insert into the seat of the mandrel.
At step 820, the material that forms the pin is introduced into the mold cavity. In embodiments, this is accomplished via injection molding, as is known in the art, although any suitable technique for introducing the material into the mold cavity may be used. The material fills the mold cavity around the mandrel (and around the neck insert, if one is used). As noted above, the material preferably comprises SURLYN™ Furthermore, while a foaming agent may be added to the material, it is preferable that no foaming agent be used in accordance with the invention.
If a neck insert was used in step 810, then step 820 may optionally include heating the neck insert to an elevated temperature before introducing the material. For example, a neck insert comprising aluminum, or other metal, may be heated to a temperature of at least 200° F., and preferably 300° F., shortly before introducing the material into the mold. Empirical observation has revealed that SURLYN™ forms a strong bond with heated aluminum. It should be noted, however, that the invention may be practiced without heating the neck insert.
At step 830, the material within the mold cavity (i.e., the pin body) is cooled. This may be accomplished by cooling the mold shell and/or mandrel in any suitable manner, as should be apparent to those of ordinary skill in the art. In embodiments, both the mold shell and mandrel are liquid-cooled by circulating a cooling liquid through passages disposed within the shell and mandrel. The cooling liquid used in the shell may be the same or a different temperature as the cooling liquid in the mandrel. This allows the precise control of the cooling rate of different portions of the pin body. Preferably, the cooling liquid of the mandrel is introduced at about 42° to 64° F., and the cooling liquid of the shell is introduced at about 42° to 64° F. The cooling liquid for both the shell and mandrel is preferably water. The pin body is cooled inside the mold for about 6 to 8 minutes.
At step 840, the mandrel is removed from the pin body. In embodiments, this is accomplished using a hydraulic apparatus that applies a force for extracting the mandrel from the body. Other methods for removing the mandrel may be employed, as should be apparent to the skilled artisan. If a neck insert is used in step 810, the neck insert remains within the body as the mandrel is removed due to the nature of the connection between the neck insert and the mandrel.
At step 850, the body is removed from the mold shell. This may be accomplished in any suitable manner, as should be apparent to the skilled artisan. In embodiments, the body is removed from the mold by separating the mold shell components (e.g., by separating halves of the mold shell) and extracting the body.
At step 860, the body is cooled again. This cooling may be accomplished in any known manner, such as, for example, air-cooling, liquid shower, or liquid bath. In embodiments, the body is cooled in a water bath or shower at a temperature of about 80° to 110° F. for a duration of about 55 to 65 minutes.
After step 860, in one implementation of the invention, the pin is substantially ready for use with no additional molding or machining steps required. For example, the final shape of the hollow area is predetermined by the shape of the mandrel (and neck insert, if one is used), and no additional machining is required in the hollow area. Also, the exterior surface does not need to be covered with another layer of material, and does not need to be machined in any way. All that remains is to apply typical decorations such as neck stripes, logos, indicia, etc. In further embodiments, additional molding and/or machining processes may be performed to eliminate any imperfections in the pin.
The foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.
