Golf shaft with bulge section

• US 5,735,753 A
• Filed: 06/14/1996
• Issued: 04/07/1998
• Est. Priority Date: 06/14/1995
• Status: Expired due to Fees

• Current Assignee: Berkley Limited
• Original Assignee: Berkley Limited
• Inventors: Hoffmeyer, Monte J.
• Primary Examiner(s): Passaniti, Sebastiano
• Application Number:
  US08/664,776
• Time in Patent Office: 662 Days
• Field of Search: 473/316, 473/317, 473/318, 473/319, 473/320, 473/321, 473/322, 473/323, 473/305, 473/306, 473/226, 473/228, 473/231, 473/256, 473/257, 473/282, 473/289, 473/219, 273/DIG. 7, 273/DIG. 23
• US Class Current: 473/318
• CPC Class Codes: A63B 2209/02 with reinforcing fibres, e.g. carbon, polyamide fibres
• CPC Class Codes: A63B 53/005 Club sets
• CPC Class Codes: A63B 53/10 Non-metallic shafts
• CPC Class Codes: A63B 60/0081 Substantially flexible shafts; Hinged shafts
• CPC Class Codes: A63B 60/06 Handles
• CPC Class Codes: A63B 60/08 characterised by the material
• CPC Class Codes: A63B 60/10 with means for indicating correct holding positions A63B60/12 takes precedence
• CPC Class Codes: A63B 60/54 with means for damping vibrations

Abstract

A composite shaft used in the manufacture of golf clubs includes a straight shaft of tapered form extending between an upper butt end a lower tip end. A radially outwardly protruding bulge section is located on the shaft with the bulge section being spaced from both the tip end of the shaft and the butt end of the shaft. The bulge section has a relatively short length compared to the length of the shaft and is located on the shaft to begin in the lower 1/3 of the shaft length.

Claims

1. A shaft suited for use as the shaft of a golf club, comprising:

a straight shaft made of composite materials comprising a resin matrix with reinforcing fibers with the shaft extending between an upper butt end and a lower tip end, the shaft including a radially outwardly protruding bulge section located on the shaft with the bulge section being spaced from both the tip end of the shaft and the butt end of the shaft, the bulge section having a relatively short length compared to the length of the shaft and being located closer to the tip end of the shaft than to the butt end of the shaft, the bulge section also being formed of additional composite materials comprising a resin matrix with reinforcing fibers such that the bulge section adds mass to the shaft compared to a shaft without the bulge section, the shaft having substantially circular cross-sectional profiles over most of its length including over the bulge section.

2. The shaft of claim 1, wherein the bulge section has a midpoint and is symmetrically shaped about a transverse axis extending through the midpoint which transverse axis is perpendicular to a longitudinal axis through the shaft.

3. The shaft of claim 2, wherein the bulge section is also symmetrically shaped about the longitudinal axis of the shaft.

4. The shaft of claim 3, wherein the midpoint of the bulge section is at a maximum diameter of the bulge section.

5. The shaft of claim 1, wherein the bulge section is symmetrically shaped about a longitudinal axis of the shaft.

6. The shaft of claim 4, wherein the shaft is uniformly tapered between its butt end and its tip end except over the bulge section.

7. The shaft of claim 6, wherein the bulge section has a maximum diameter that lies in the range of 1.05 to 1.5 times the diameter the shaft would have had at the same point in a straight shaft that was entirely uniformly tapered between its butt end and its tip end.

8. The shaft of claim 1, wherein the distance between the tip end of the shaft and a start of the bulge section is in the range of approximately 3 inches to 12 inches.

9. The shaft of claim 8, wherein the length of the bulge section does not exceed about 25% of the length of the shaft.

10. The shaft of claim 9, wherein the bulge section adds approximately 5% to 10% additional weight to the shaft than the weight of a shaft without the bulge section.

11. The shaft of claim 1, wherein the additional composite material being provided by the bulge section has a variable thickness along the length of the bulge section characterized by low thickness at either end of the bulge section and by maximum thickness at a location somewhere between the ends of the bulge section.

12. The shaft of claim 11, wherein the maximum thickness of the bulge section mat&

rial is located within a middle 50% of the bulge section.

13. The shaft of claim 12, wherein the maximum thickness of the bulge section material is located at a midpoint of the bulge section.

14. The shaft of claim 1, wherein a majority of the reinforcing fibers in the bulge section material are oriented substantially parallel to a longitudinal axis of the shaft to enhance the rigidity in the bulge section.

15. The shaft of claim 14, wherein substantially all of the reinforcing fibers in the bulge section material are oriented substantially parallel to a longitudinal axis of the shaft to enhance the rigidity in the bulge section.

16. A shaft suited for use as the shaft of a golf club, comprising:

a straight shaft made of composite materials comprising a resin matrix with reinforcing fibers with the shaft extending between an upper butt end and a lower tip end, the shaft including a radially outwardly protruding bulge section located on the shaft with the bulge section being spaced from both the tip end of the shaft and the butt end of the shaft, the bulge section having a relatively short length compared to the length of the shaft and beginning proximately 3 to 12 inches from the tip end of the shaft, the bulge section also being formed of composite materials comprising a resin matrix with reinforcing fibers, and wherein the bulge section provides additional composite material and the additional composite material being provided by the bulge section has a variable thickness along the length of the bulge section characterized by low thickness at either end of the bulge section and by maximum thickness at a location somewhere between the ends of the bulge section, the shaft having substantially circular cross-sectional profiles over most of its length including over the bulge section.

17. A shaft suited for use as the shaft of a golf club, comprising:

a straight shaft made of composite materials comprising a resin matrix with reinforcing fibers with the shaft extending between an upper butt end and a lower tip end, the shaft including a radially outwardly protruding bulge section located on the shaft with the bulge section being spaced from both the tip end of the shaft and the butt end of the shaft, the bulge section having a relatively short length compared to the length of the shaft and being located closer to the tip end of the shaft than to the butt end of the shaft, and wherein the bulge section provides additional material and the additional material being provided by the bulge section has a variable thickness along the length of the bulge section characterized by low thickness at either end of the bulge section and by maximum thickness at a location somewhere between the ends of the bulge section, the shaft having substantially circular cross-sectional profiles over most of its length including over the bulge section.

18. The shaft of claim 17, wherein the bulge section has a length of approximately 3 to 8 inches and begins approximately 3 to 12 inches from the tip end of the shaft.

19. The shaft of claim 18, wherein the maximum thickness of the bulge section material is located at a midpoint of the bulge section.

20. The shaft of claim 18, wherein the bulge section is formed of material having reinforcing fibers, and wherein substantially all of the reinforcing fibers in the bulge section material are oriented substantially parallel to a longitudinal axis of the shaft to enhance the rigidity in the bulge section.

21. A shaft suited for use as the shaft of a golf club, comprising:

a straight shaft made of composite materials comprising a resin matrix with reinforcing fibers with the shaft extending between an upper butt end and a lower tip end, the shaft including a radially outwardly protruding bulge section located on the shaft with the bulge section being spaced from both the tip end of the shaft and the butt end of the shaft, the bulge section having a relatively short length compared to the length of the shaft and beginning approximately 3 to 12 inches from the tip end of the shaft, the bulge section also being formed of composite materials comprising a resin matrix with reinforcing fibers, and wherein the shaft has a variable outer diameter along the length of the bulge section characterized by outer diameters at either end of the bulge section which are smaller than a maximum outer diameter at a location somewhere between the ends of the bulge section, the shaft having substantially circular cross-sectional profiles over most of its length including over the bulge section.