Golf club shaft

Abstract

An improved method for preparing a golf club shaft out of a shaft rod is disclosed. This method utilizes a marking directly provided on the shaft rod. The marking may be scale, wording or marks. The marking provides cutting information to be adequately utilized by workers in cutting operations. The marking additionally provides property information of the shaft or a golf club incorporating the shaft.

Description

[0001] This application claims priority from Japanese Patent Application No. 2000-240832 filed Aug. 9, 2000 entitled “Golf Club Shaft.”

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to a golf club shaft. More particularly, the present invention relates to a method for preparing a golf club shaft out of a shaft rod utilizing a marking or markings provided on the shaft rod, which provide processing information as well as property information.

[0004] 2. Related Art

[0005] As is generally known and typically shown in FIG. 5, a conventional golf club 100 is typically comprised of an elongated shaft 10, a club head 40 integrally having a hosel 60, a socket member 50 and a grip member 70. The hosel 60 receives a tip end portion of the shaft 10 and integrally secures the club head 40 thereto with an adhesive.

[0006] The length of the tip end portion of the shaft 10 to be inserted into the hosel 60 is typically predetermined according to desired properties for the shaft 10.

[0007] The socket member 50 is securely mounted on a preset portion of the shaft 10 and functions to control the length of insertion of the shaft tip portion into the hosel 60. Typically, such control is important to effectively retain the adhesion between the tip portion and the hosel 60.

[0008] The socket member 50 additionally functions to partially absorb physical energy or shock that a basal portion of the head 40 or the hosel portion accidentally receives in use and will protect the golf club 100 from damages such as breaking or cracking in the vicinity of the socket member 50.

[0009] Conventional and typical processes to integrate the club head 40 onto the club shaft 10 are briefly described hereunder.

[0010] According to designed properties of a shaft 10 such as its overall length, weight, diameter, flex, elasticity and stiffness, an optimum shaft rod is selected.

[0011] The shaft rod is cut at a first distance from its tip and/or at a second distance from its butt to provide a club shaft 10 having a designed length for the designed properties of the shaft 10.

[0012] Typically, there is provided a degree of clearance between the surface of the portion of the shaft 10 inserted in the hosel 60 and the inner surface of the hosel 60 so as to facilitate easy insertion and provide secure adhesion therebetween with an adhesive. Such clearance may be provided by grinding or abrading the surfaces of the inserted portion of the shaft 10 and the hosel 60 with appropriate grinding or abrading means.

[0013] Before the insertion, both surfaces are typically washed and thoroughly cleaned. After the insertion, the inserted portion of the shaft 10 is securely integrated with the hosel 60 with a powerful glue or adhesive. A grip member 70 is mounted on a grip portion of the shaft 10 and secured thereon to provide a grip of a golf club 100.

[0014] With a conventional method of producing golf clubs, it is not readily known to workers where exactly to cut shaft rods for particular properties thereof as there are provided no cutting indications or information on conventional shaft rods. Conventionally, workers manually provide cutting markings on shaft rods one by one before individual cutting and then cut the shaft rods at those cutting markings, which is laborious and time consuming.

[0015] With conventional golf clubs, it is not readily known, either, where shaft rods have been cut after tip portions of the shafts have been inserted into club heads 40 or grip members are mounted on the shafts. Golfers may wish to know exact properties of their golf clubs that are subject to the cutting processes.

SUMMARY OF THE INVENTION

[0016] Accordingly, it is an object of the present invention to provide a shaft rod with cutting information that facilitates precise and efficient cutting of the shaft rod.

[0017] It is another object of the present invention to provide a golf club with adequate information about the properties of the golf club that have been provided after shaft rod cutting.

[0018] According to the present invention, cutting information is provided directly on a shaft rod. The cutting information may be a marking provided in a tip portion and/or butt portion of the shaft rod. Such information is provided by letters, marks or colors. Other types of indications or a blend of a variety of indications may be utilized as well.

[0019] The shaft rod having such information or a marking is typically cut according to separately provided cutting instructions that instruct workers where on the marking to cut the shaft rod.

[0020] A golf club comprising or incorporating a shaft prepared or cut in accordance with the present invention provides properties such as flex, torque, stiffness, weight, etc. to the golf club practically exactly as desired or designed. Information about the length of the shaft in the golf club may additionally be provided.

[0021] It is therefore possible to provide golf clubs made to order according to individual tastes of golfers who may be extra particular about individual properties of their golf clubs.

[0022] Such markings provide information where the shaft rod has been cut even after a club head and a grip member have been mounted on the shaft and no traces of cut sections are in view. Golfers looking for a golf club with particular properties can easily find one that exactly satisfies their desires.

[0023] Such markings can also provide information about the limitation to the distance that can be cut off from a shaft rod. A tip portion of a shaft rod is provided uniformly without tapering. Therefore, if a shaft rod is cut at an excessively long distance from its tip, the shaft is very likely tapered there. A tapered portion would not be safely secured in a hosel. Such excessive cutting would invite deterioration to the performance of golf clubs as well.

[0024] A butt end portion of a shaft rod should not be freely cut off, either. Excessive cutting-off might lead to accidental breaking of the adhesion between a grip portion of the shaft and a grip member, for there would be created excessive gap between the grip portion and the grip member since the grip portion there would be “too” thin for the “typically mass-produced” grip member.

[0025] As such markings may automatically be provided at the time of manufacturing shaft rods, no extra manual marking work is required, greatly saving on labor and processing time.

[0026] It is an additional object of the present invention to provide a method for preparing a club shaft out of a shaft rod by cutting off an end portion or portions of the shaft rod so as to provide desired properties of the shaft or a golf club comprising the shaft.

[0027] It is yet another object of the present invention to provide a method for readily and efficiently cutting off an end portion or portions of a shaft rod so as to provide designed properties to a shaft prepared out of the shaft rod.

[0028] Other objects of the present invention will be readily understood by ones skilled in the relevant art by reading the descriptions that follow together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1(a) schematically shows a shaft rod to be cut according to the present invention;

[0030] FIG. 1(b) schematically shows a tip end portion of a shaft rod having cutting information thereon according to an embodiment of the present invention;

[0031] FIG. 1(c) schematically shows a butt end portion of a shaft rod having cutting information thereon according to an embodiment of the present invention;

[0032] FIG. 1(d) schematically shows a butt end portion of a shaft rod having cutting information thereon according to another embodiment of the present invention;

[0033] FIG. 2 schematically shows a club head into which a tip portion of a shaft having cutting information thereon is inserted according to an embodiment of the present invention;

[0034] FIG. 3 schematically shows a club head into which a tip portion of a shaft having cutting information is inserted after a larger cut-off;

[0035] FIG. 4 schematically shows a club head into which a tip portion of a shaft having cutting information is inserted after a largest cut-off;

[0036] FIG. 5 schematically shows a typical golf club;

[0037] FIG. 6(a) is a table of instructions forming part of the present invention in an embodiment, according to which workers are instructed where to cut shaft rods and golfers can know properties of golf clubs; and

[0038] FIG. 6(b) is another table of instructions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0039] In FIG. 1(a) is shown a shaft rod to be a shaft 1 after going through a cutting step. It is noted that in exceptional cases, it is possible for a shaft rod to be a shaft 1 without going through any cutting steps. An encircled tip end portion 2 provided in the vicinity of the tip of the shaft 1 or rod is to be inserted into a hosel of a head. An encircled butt end portion 3 provided in the vicinity of the butt of the shaft 1 or rod is to provide a grip of a golf club.

[0040] In FIG. 1(b) is shown an enlarged tip end portion 2 on which cutting information or a marking M in a form of scale S is provided according to an embodiment of the present invention. The scale S in this embodiment is divided or calibrated at 5 mm intervals. Such scale S may be divided at other intervals such as 10 mm intervals, or 1-13 mm intervals.

[0041] In an alternative embodiment, the scale S is divided at ½ inch intervals. In yet another alternative embodiment, the scale S is divided at ¼ intervals. The scale S may be provided in other inch units as well.

[0042] In FIG. 1(c) is shown an enlarged butt end portion 3 on which cutting information or a marking M in a form of scale S is provided according to an embodiment of the present invention. The scale S in this embodiment is divided at 5 mm intervals. Such scale S may be divided at other intervals such as 10 mm intervals, or 1-13 mm intervals.

[0043] In an alternative embodiment, the scale S is provided in inch with ½ inch intervals. In yet another alternative embodiment, the scale S is divided at ¼ intervals. Such scale S may be provided in other inch units as well.

[0044] In FIG. 1(d) is shown an enlarged butt end portion 3 on which cutting information or a marking M in a form of scale S is provided according to an embodiment of the present invention. The scale S in this embodiment is calibrated at 5 mm intervals. Such scale S may be calibrated at other intervals such as 10 mm intervals, or 1-13 mm intervals.

[0045] The scale S of this embodiment is further provided with numbers indicating distances in millimeter from the butt of the rod in order to facilitate efficient cutting operation and provide golfers with easily noticeable information where cutting has been done. The numbers may be replaced by other letter or mark indications.

[0046] In an alternative embodiment, the scale S is divided at ½ inch intervals. In yet another alternative embodiment, the scale S is divided at ¼ inch intervals. The scale S may be provided in other inch units as well.

[0047] The markings of the present invention may be provided on golf clubs such that the markings are not viewed by players who are addressing a ball using the golf clubs.

[0048] Workers are provided with cutting instructions including tables such as shown in FIG. 6(a) or FIG. 6(b) as an example. The cutting instructions provide lengths to be cut off from tip ends or butt ends of shaft rods, or both. The predetermined lengths or distances from the ends of shaft rods can be readily and precisely located on the scales S. Workers simply cut the shaft rods according to the instructions.

[0049] Golfers may be provided with information including tables such as shown in FIG. 6(a) or FIG. 6(b) as an example, and can be provided with particular properties of individual golf clubs from the markings M.

[0050] In FIG. 2 is shown an embodiment of utilization of the present invention, where a head 4 having a hosel 6 is mounted securely on a tip end portion of a shaft 1, and a socket member 5 having a height about 10 mm is also mounted securely on the shaft 1, the lower face of the socket member 5 contacting the upper end face of the head 4.

[0051] The tip end portion is provided with a marking M comprising scale S according to the present invention. The original marking M is 80 mm long in this embodiment, which may be indicated on the shaft or taught otherwise. Other original lengths can equally be utilized.

[0052] The scale S in this embodiment is calibrated at 5 mm intervals, of which 10 mm intervals are indicated with longer lines. A measured length has been cut off from a tip end portion of the shaft rod in accordance with cutting instructions.

[0053] In this embodiment, about 30 mm from the tip of the shaft 1 is inserted in the hosel 6 and about 10 mm is covered with the socket member 5. The shaft portion inserted in the hosel 6 is integrally adhered with an adhesive to the inner surface of the hosel 6. The socket member 5 is secured somehow to the shaft portion covered with the socket member 5.

[0054] In one embodiment, a socket member 5 is heated to expand, and is placed on an appropriate location of a shaft 1. As the socket member 5 is cooled, the socket member 5 is squeezed on the shaft 1 and gets tightened on the shaft 1. The tightened socket member 5 controls the depth of insertion of the shaft tip portion into a hosel 6. In another embodiment, a socket member 5 is adhered to the shaft 1 with an adhesive.

[0055] The exposed portion of the scale 5, in this example 40 mm, indicates or teaches viewers the length of the cut-off portion (0 mm in this embodiment) and provides other information in relation to the cut. An example of properties of a golf club shaft in relation to the lengths of cut-off portions is provided in the table of FIG. 6(a), which is to be described in detail later.

[0056] In an alternative embodiment, a zone beyond a “safe” distance from the tip or butt of a shaft rod or a “dangerous” zone is indicated on the marking M in warning color such as red. Other colors may equally be utilized.

[0057] In FIG. 3 is shown another embodiment of the present invention. In this embodiment, a longer distance (20 mm) has been cut off from the tip of a shaft rod, providing slightly different properties from the foregoing embodiment.

[0058] In FIG. 4 is shown still another embodiment of the present invention. In this embodiment, a maximum length (40 mm) for this particular embodiment has been cut off from the shaft rod, providing still different properties.

[0059] As used here, there is a maximum length to be safely cut off from a tip end portion or a butt end portion a shaft rod. Such maximum lengths will differ case by case depending upon physical properties of shaft rods.

[0060] There is provided a table in FIG. 6(a). This table provides properties of a shaft, “flex”, “torque”, “club length” and “diameter” in relation to the lengths of cutoff (0-50 mm). The diameter at the butt of this particular shaft rod is 15.60 mm. The letter “5” stands for “stiff” and the letter “X” stands for “extra stiff.” The larger the number affixed to the letter “5” or “X”, the higher the stiffness within the “5” level or “X” level. The club length is provided in inch as it is customary to use inches for golf clubs. The torque is provided in “°/ft·lb” as it is customary to use this unit.

[0061] The “diameter (shaft tip)” in the table is the diameter as measured at the shaft portion which is to contact the upper end of the socket member 5 after a cut-off. With the shaft rod of this embodiment, the shaft rod portion up to 80 mm from the tip end of the shaft rod is provided in an identical diameter all through. Past the 80 mm portion, the shaft rod gradually becomes thicker.

[0062] The table shows that the diameter of the shaft measured at the socket member contacting portion is equal in diameter at 8.65 mm up to 40 mm of the “cut length” as the first 40 mm tip end portion of the shaft rod is to be inserted into the hosel 60 of the head 4 and the socket member 5. The hosel 60 is about 30 mm deep and the socket member 5 is about 10 mm tall in this embodiment. This shaft starts changing its thickness at a distance around 50 mm from the tip end.

[0063] If an excessive length is cut off beyond the 40 mm mark, the hosel 60 is to receive a tapered portion, at least partially, which will not provide a very secure integration between the hosel 60 and the shaft portion.

[0064] FIG. 6(b) provides another table. In this table all lengths are provided in inch, and the diameter at the butt of this particular shaft rod is 0.614 inch.

[0065] Golfers who are particular about “flex” and/or “torque” of golf clubs can select “best” golf clubs that provide “flex” and/or “torque” to their individual preferences.

[0066] It is to be noted that shafts with different diameters will provide different properties. Materials of shafts will greatly affect properties as well. Other physical properties of shafts would also affect properties of golf clubs. Sizes and/or weights of club heads also affect properties of golf clubs.

[0067] While the invention has been described using various embodiments, alterations or modifications to the embodiments may be made within the scope of the invention as defined in the “claims”, which are all intended to be within the scope of the present invention.

Claims

1. A golf club shaft made from a shaft rod having thereon at least one marking which comprises cutting information to be utilized in a shaft cutting operation so as to provide said golf club shaft with a desired performance property.

2. A golf club shaft according to claim 1, wherein said marking is provided in a length which facilitates utilization thereof after said shaft has been incorporated into a golf club.

3. A golf club shaft according to claim 1, wherein said marking comprises scale.

4. A golf club shaft according to claim 3, wherein said scale is calibrated at intervals between 1 mm and 13 mm.

5. A golf club shaft according to claim 3, wherein said scale is calibrated at 5 mm intervals.

6. A golf club shaft according to claim 3, wherein said scale is calibrated at 10 mm intervals.

7. A golf club shaft according to claim 3, wherein said scale is calibrated at ½ inch intervals.

8. A golf club shaft according to claim 3, wherein said scale is calibrated at ¼ inch intervals.

9. A golf club shaft according to claim 3, wherein said scale includes length indicating numerals.

10. A golf club shaft according to claim 1, wherein said marking is provided on said shaft to be out of sight of a player who is addressing a ball using a golf club incorporating said shaft.

11. A golf club shaft according to claim 1, wherein said marking is provided on said shaft rod at a tip end portion thereof.

12. A golf club shaft according to claim 1, wherein said marking is provided on said shaft rod at a butt end portion thereof.

13. A golf club shaft according to claim 1, wherein said golf club shaft has been cut according to cutting information provided in a table of properties in relation to the length of a golf club shaft made from a shaft rod on which said cutting information is prepared.

14. A method for cutting a shaft rod to provide a golf club shaft, comprising the step of cutting said shaft rod according to a marking comprising cutting information which is provided on said shaft rod.

15. A method for cutting a shaft rod to provide a golf club according to claim 14, said cutting information comprising scale which is calibrated at 10 mm intervals.

16. A method for cutting a shaft rod to provide a golf club according to claim 14, said cutting information comprising scale calibrated at 5 mm intervals.

17. A method for cutting a shaft rod to provide a golf club according to claim 14, said cutting information comprising scale calibrated at ½ inch intervals.

18. A method for cutting a shaft rod to provide a golf club according to claim 14, said cutting information comprising scale calibrated at ¼ inch intervals.

19. A method for cutting a shaft rod to provide a golf club according to claim 14, wherein cutting by said method is performed according to cutting information provided in a table of properties in relation to the length of a golf club shaft made from a shaft rod on which said cutting information is prepared.