Patent Application
20120165109
The present application claims priority on Patent Application No. 2010-290617 filed in JAPAN on Dec. 27, 2010, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a golf club capable of adjusting a club balance.
2. Description of the Related Art
A club balance (swingweight) of a golf club contributes to easiness of swing. Club balances suitable for golf players are different. In order to adjust the club balance, there are provided a golf club having a shaft having one end into which a weight object is inserted, a golf club having a head into which a gel is injected, and a golf club having the shaft having the other end to which the weight object is mounted, or a grip to which the weight object is mounted, or the like.
For example, a golf club having a grip to which a weight is detachably mounted is disclosed in Japanese Patent Application Publication No. 4507266 (US2011/124431). A golf club having a grip end to which a weight is mounted so as to protrude from the grip end is disclosed in Japanese Patent Application Publication No. 3826313 (US2004/38762, US2006/63618) and Japanese Patent Application Laid-Open No. 2001-252377. A golf club having a shaft having one end to which a weight is movably mounted is disclosed in Japanese Utility Model Application Laid-Open No. 06-39039 and Japanese Utility Model Application Laid-Open No. 05-82454.
In these golf clubs, a weight balance of the club can be changed by replacing the weight and by changing the mounting position of the weight. The club balance is adjusted by changing the weight balance. Thereby, the golf club can be adjusted to the club balance suitable for the golf player.
An impact transmitted to hands when a ball is hit by a golf club having a reduced weight is apt to be increased. An impact transmitted to the hands when the ball is hit at an off-center is apt to be further increased. A golf club having a shaft to which a weight is mounted in order to absorb the impact vibration is disclosed in Japanese Patent Application Laid-Open No. 10-71222. A weight covered with an elastic body is detachably mounted to the golf club. The golf club can absorb the impact vibration.
The grip held by the golf player is made of a relatively soft material. The mounting position of the weight object detachably mounted to the grip is hardly stabilized. When the weight object is mounted by a screw, the weight object is can be certainly fixed. However, the attaching/detaching operation requires time and effort. The weight of the weight object is not changed in the golf club in which the mounting position of the weight object is changed to adjust the club balance. Thereby, when a position of the weight object is not greatly changed, it is difficult to sufficiently adjust the club balance. The adjusting operation of the club balance in the golf club also requires time and effort.
The weight saving of the golf club is further advanced, which is apt to increase an impact force received by the hands. Further improvement of vibration absorptivity of the golf club is also demanded.
It is an object of the present invention to provide a golf club having an easily adjusted club balance and having excellent vibration absorptivity.
A golf club according to the present invention includes a shaft, a grip mounted to an end part of the shaft, a cavity body mounted to the end part of the shaft to which the grip is mounted, and a weight body detachably mounted to the cavity body. The cavity body is made of a polymer.
Preferably, an outer peripheral surface of the cavity body is mounted to an inner peripheral surface of the shaft so as to abut on the inner peripheral surface. Two or more projections are formed on one of the outer peripheral surface of the cavity body and the inner peripheral surface of the shaft. Two or more recessed parts are formed on the other. The two or more projections are engaged with the two or more recessed parts.
Preferably, a complex elastic modulus (a measured value under conditions of a temperature of 5° C. and a frequency of 10 Hz) of the polymer of the cavity body is 1.0×108 dyn/cm2 or greater and 1.0×1010 dyn/cm2 or less.
Preferably, the weight body includes a headpart, an engaging part, and a neck part located between the head part and the engaging part. The engaging part has a noncircular sectional shape. The cavity body includes an internal space, an inner surface surrounding the internal space, and a through hole extending through the internal space from an upper surface of the cavity body. The through hole has a noncircular shape.
An attitude of the weight body can be changed between a disengaged attitude and an engaged attitude by rotating the weight body to the cavity body by a predetermined angle θ with an axis line of the through hole as a rotation axis in an inserted state where the engaging part and the neck part are inserted into the cavity body from the through hole.
The head part of the weight body abuts on the upper surface of the cavity body in the inserted state. The neck part is located in the through hole. The engaging part is located in the internal space. The engaging part and the neck part can be drawn out from the through hole in the disengaged attitude. The engaging part is engaged with an edge of the through hole in the engaged attitude, so that the engaging part and the neck part cannot be drawn out from the through hole.
The inner surface surrounding the internal space of the cavity body includes a resistance surface and an abutting surface. The abutting surface abuts on the engaging part in the engaged attitude. When the attitude is changed to the engaged attitude from the disengaged attitude, the resistance surface slides with the engaging part, to apply a rotation resistance. The engaging part is positioned in a rotating direction by the abutting surface and the resistance surface in the engaged attitude.
Preferably, the angle θ is equal to or less than 90 degrees.
Preferably, the cavity body includes an insertion part inserted into the shaft and a collar part abutting on an end face of the shaft. A plurality of cavity bodies is provided, which have collar parts having different lengths in an axial direction of the shaft. One of the plurality of cavity bodies is mounted, to enable adjustment of a length of the golf club.
Preferably, the cavity body includes two or more polymers. The polymers have different complex elastic modulus.
Since the weight body is mounted to the shaft via the cavity body including the polymer in the golf club according to the present invention, the weight body is easily mounted/dismounted, to easily adjust a club balance. The golf club has excellent vibration absorptivity.
Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate references to the drawings.
A golf club 2 of
The head 4 is a wood type head. The head 4 is exemplary. An iron type head and a putter type head may be used in place of the head 4. The shaft 6 has a long cylindrical shape. Examples of the shaft 6 include a steel shaft and a so-called carbon shaft.
The grip 8 has an approximately cylindrical shape. Although not shown in the drawings, grooves are formed in a holding surface 8a which is an outer peripheral surface of the grip 8. When a golf player swings the golf club 2, the golf player holds the holding surface 8a.
Although a material of the grip 8 is not particularly restricted, the material is preferably a rubber. For example, a natural rubber, a styrene-butadiene rubber, EPDM, an isoprene rubber, and a mixture thereof are preferable. In respect of moldability of the grip 8, the EPDM and the styrene-butadiene rubber are more preferable.
As shown in
As shown in
A through hole 22 and a hole 24 as an internal space are formed in the cavity body 10. The through hole 22 extends through the hole 24 from the upper part of the cavity. For example, a section of the through hole 22 has an approximately square shape. Herein, the approximately square shape is exemplified as the section of the through hole 22. However, the section of the through hole 22 may be a section having a noncircular shape such as a rectangle, a pentagon, or an ellipse shape.
The hole 24 is formed to reach a predetermined depth L1 from a lower end face of the cavity body 10. The hole 24 is surrounded by an inner surface 25. The inner surface 25 has a resistance surface 26 and an abutting surface 27.
The cavity body 10 is made of a polymer. The polymer is hard. The polymer can be elastically deformed. The polymer is preferably a resin or a rubber. Herein, the description will be made using the resin as an example. In respect of proccessability, a thermoplastic resin and a fiber-reinforced resin thereof are preferable as the resin. Examples thereof include polyurethane, a polyether block copolymer, and polycarbonate.
As shown in
The engaging part 32 has a noncircular section. For example, the section has an approximately square shape. The engaging part 32 can pass through the through hole 22. Herein, the engaging part 32 is a quadranglar prism. A double-pointed arrow L2 shows a length of one side of the approximately square shaped section of the engaging part 32. A double-pointed arrow L3 shows a length of a diagonal line of the approximately square shaped section. The length L2 is made the same as the outer diameter D4 of the neck part 30. A length L3 is made greater than the outer diameter D4 of the neck part 30. The engaging part 32 has a bottomed hole 38 formed from a lower end face thereof.
The engaging part 32 has a corner part 32a as a protruding part. The corner part 32a protrudes to a radial direction of the weight body 12. A protruding amount (a protruding amount from a center of the engaging part 32 in the radial direction) of the corner part 32a of the engaging part 32 is set to ½ of the length L3.
A material having a specific gravity greater than that of the cavity body 10 is used for the weight body 12. In respect of durability and the specific gravity, examples of the material of the weight body 12 include a metal such as an aluminum alloy, a titanium alloy, or a tungsten alloy.
As shown in
The engaging part 32 of the weight body 12 is penetrated through the through hole 22 of the cavity body 10. The neck part 30 and engaging part 32 of the weight body 12 are inserted into the cavity body 10, so that the weight body 12 is brought into in an inserted state. In the inserted state, the head part 28 of the weight body 12 abuts on an upper surface 10a of the cavity body 10. The neck part 30 is located in the through hole 22. The engaging part 32 is located in the hole 24.
In a state where the neck part 30 and the engaging part 32 are merely inserted, the neck part 30 and the engaging part 32 are drawably inserted from the through hole 22. An attitude in which the weight body 12 is drawably inserted is a disengaged attitude. When the weight body 12 is rotated with respect to the cavity body 10 in the inserted state with an axis line of the through hole 22 as a rotation axis, the engaging part 32 is engaged with an edge 22a of the through hole 22. A part of the edge 22a enters between the head part 28 and the engaging part 32. The neck part 30 and the engaging part 32 take such an attitude that the neck part 30 and the engaging part 32 cannot be drawn from the through hole 22. The attitude in which the weight body 12 cannot be drawn from the cavity body 10 is an engaged attitude. In the engaged attitude, the weight body 12 is mounted to the cavity body 10 so as to be engaged with the cavity body 10.
An angle θ of
A screwdriver 42 of
As shown in
A pair of pockets 56 is formed in the holding body part 52a. The holding body part 52a is closed by the lid 52b. The weight body 12 is housed in one pocket 56, and a weight body 58 is housed in the other pocket 56. The weight body 12 or 58 can be taken out by opening the lid 52b.
Although not shown in the drawings, dimensions and shapes of the cutout 36 and bottomed hole 38 of the weight body 12 are different from those of the weight body 58. Thereby, even when a material of the weight body 12 is the same as that of the weight body 58, a mass of the weight body 12 is different from that of the weight body 58. Materials having different specific gravities may be used for the weight bodies 12 and 58 while a shape of the weight body 12 is made the same as that of the weight body 58.
The number of the pockets 56 is not restricted to 2. The number may be 1, or equal to or greater than 3. The number of the weight bodies to be housed may be 1, or equal to or greater than 3. A section of the blade edge 48 corresponds to the quadrangle hole 34 of the weight body 12. The section of the blade edge 48 may correspond to the sectional shape of the hole of the weight body 12 with which the blade edge 48 is engaged. The sectional shape of the blade edge 48 is not restricted to the above-mentioned quadrangle.
A section of the shaft 6 and vicinity of a grip end of the grip 8, and a section of the cavity body 10 are shown in
The weight body 12 and the cavity body 10 which are in the disengaged attitude are shown in
A method for attaching the weight body 12 will be described with reference to
The weight body 12 is inserted into the opening 8b of the grip 8 from the grip end in a state where the weight body 12 is engaged with the blade edge 48. The engaging part 32 of the weight body 12 is penetrated through the through hole 22 of the cavity body 10. The head part 28 abuts on the collar part 18. Thus, the cavity body 10 and the weight body 12 are brought into in a state of the disengaged attitude shown in
In the state of the disengaged attitude, the screwdriver 42 is rotated clockwise. An arrow R of
While the corner part 32a of the engaging part 32 slides on the resistance surface 26, the weight body 12 is rotated with respect to the cavity body 10. The resistance surface 26 applies a rotation resistance to rotation of the engaging part 32. The cavity body 10 is elastically deformed by the sliding. When the weight body 12 is rotated by the angle θ, the corner part 32a abuts on the abutting surface 27 of the hole 24. The corner part 32a is positioned in the rotating direction by the resistance surface 26 and the abutting surface 27. The corner part 32a of the engaging part 32 is engaged with the through hole 22 of the cavity body 10. The weight body 12 is positioned in the rotating direction and the axial direction with respect to the cavity body 10. Thus, the cavity body 10 and the weight body 12 are brought into in a state of the engaged attitude shown in
As shown in
A method for changing the weight body 12 to the other weight body 58 will be described. The cap 14 is removed. The blade edge 48 of the screwdriver 42 is inserted into the quadrangle hole 34 of the weight body 12. The weight body 12 is in the engaged attitude of
The screwdriver 42 is drawn out in the direction away from the shaft 6. Since the quadrangle hole 34 and the blade edge 48 are engaged with each other, the weight body 12 is drawn out in the direction away from the shaft 6. The engaging part 32 passes through the through hole 22, so that the weight body 12 is drawn out from the cavity body 10. Thus, the cavity body 10 and the weight body 12 is brought into the state of
The weight body 12 is removed from the blade edge 48 of the screwdriver 42. The lid 52b of the screwdriver 42 is opened, and the weight body 12 is then housed in the vacant pocket 56 (see
In the golf club 2, the weight body 12 is fixed to the cavity body 10 by rotating the weight body 12 by the angle θ. The fixation is released by reversely rotating the weight body 12 by the angle θ. In the golf club 2, the weight body 12 is easily attached/detached. In respect of easily attaching/detaching the weight body, the angle θ is preferably equal to or less than 90 degrees, and more preferably equal to or less than 45 degrees.
The attaching structure is exemplary, and the present invention is not restricted to the attaching method. For example, the attaching structure may be a so-called BNC connector type attaching structure. In respect of detachably fixing the weight body 12 to the cavity body 10 certainly, the weight body 12 may be merely screwed into the cavity body 10 so as to be fixed to the cavity body 10.
As shown in
Vibration energy of the hitting vibration is converted into kinetic energy of the weight body 12 housed in the cavity body 10 made of an elastic body. The cavity body 10 and the weight body 12 convert the vibration energy of the shaft 6 into the kinetic energy of the weight body 12 to alleviate the hitting vibration.
In respect of certainly fixing the weight body 12 to the cavity body 10, a complex elastic modulus of a resin of the cavity body 10 is preferably equal to or greater than 1.0×108 dyn/cm2, and more preferably equal to or greater than 5.0×108 dyn/cm2. In respect of vibration absorptivity, the complex elastic modulus is preferably equal to or less than 1.0×1010 dyn/cm2, and more preferably equal to or less than 5.0×109 dyn/cm2.
Examples of the material having a complex elastic modulus include “Himilan 1605” (trade name) manufactured by DUPONT-MITSUI POLYCHEMICALS CO., LTD, “Pebax 5533” (trade name) manufactured by ARKEMA, and “RILSAN-BMNO” (11-Nylon) (trade name) manufactured by ARKEMA.
The complex elastic modulus can be measured using a viscoelastic measuring apparatus (viscoelastic spectrometer DVA200 advanced model manufactured by SHIMADZU CORPORATION). The measurement conditions are as follows.
A cavity body 62 of a golf club according to another embodiment of the present invention is shown in
In the cavity body 62, two different polymers are brought into contact with the shaft 6. The two different polymers are brought into contact with the weight body 12. Vibration energies having different frequencies can be absorbed by combining the two polymers.
Since the complex elastic modulus of the polymers of the upper part 64 and the lower part 68 are increased, the weight body 12 can be certainly fixed. The cavity body 62 can be certainly fixed to the shaft 6. Preferably, the complex elastic modulus of the upper part 64 and lower part 68 are preferably equal to or greater than 1.0×108 dyn/cm2, and more preferably equal to or greater than 5.0×108 dyn/cm2. The complex elastic modulus of the upper part 64 and lower part 68 are preferably equal to or less than 1.0×1010 dyn/cm2, and more preferably equal to or less than 5.0×109 dyn/cm2. The complex elastic modulus of the middle part 66 is more preferably equal to or less than 5.0×109 dyn/cm2, more preferably equal to or less than 1.0×109 dyn/cm2, and particularly preferably equal to or less than 5.0×108 dyn/cm2.
The upper part 64, middle part 66, and lower part 68 of the cavity body 62 may be made of polymers having different complex elastic modulus. Furthermore, the upper part 64, the middle part 66, and the lower part 68 may be made of four or more polymers.
A cavity body 70 of a golf club according to still another embodiment of the present invention is shown in
In the cavity body 70, the complex elastic modulus of the polymer of the outer peripheral part 72 may be made smaller than that of the polymer of the inner peripheral part 74. Since the cavity body 70 is made of two polymers, vibration energies having different frequencies tend to be absorbed. Preferably, the complex elastic modulus of the outer peripheral part 72 and inner peripheral part 74 are preferably equal to or greater than 1.0×109 dyn/cm2, and more preferably equal to or greater than 5.0×108 dyn/cm2. The complex elastic modulus of the outer peripheral part 72 and inner peripheral part 74 are preferably equal to or less than 1.0×1010 dyn/cm2, and more preferably equal to or less than 5.0×109 dyn/cm2.
A section of a vicinity of a grip end of a golf club 76 according to yet still another embodiment of the present invention is shown in
A collar part 82 of the cavity body 78 is made longer than the collar part 18 of the cavity body 10 in an axial direction. Thereby, the golf club 76 has a changed club balance and length. The grip 80 is used in place of the grip 8 with the change of the length.
The golf club 76 has the plurality of cavity bodies having different lengths in the axial direction, and thereby the length thereof can be adjusted. The position of the weight body 12 can be also greatly changed. In the golf club 76, the weight body and the mounting position of the weight body can be easily changed. The club balance of the golf club 76 can be easily adjusted in a wide range. Furthermore, for example, even if the different cavity bodies are used, a common grip can be also used. When the common grip is used, an outer peripheral surface of the collar part 82 of the cavity body 78 is preferably located on the extension of the outer peripheral surface of the shaft 6.
Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be interpreted in a limited way based on the description of examples.
“SRIXON ZR-700 Driver” (trade name) manufactured by SRI Sports Limited was used as it was. A mass of a grip was 50 g.
A remodeled club of “SRIXON ZR-700 Driver” (trade name) in which a vicinity of a grip end was remodeled was prepared as shown in
Valuation methods are as follows.
A swing weight was measured by using “BANCER-14” (trade name) manufactured by DAININ Corporation. The swing weight is a 14-inch type. The measured values are shown in the following Table 1.
ζ=(½)×(Δω/ωn)
To=Tn×√2
However, as shown in a graph of
Each of twenty intermediate- or high-level golf players (satisfying conditions where the golf players have golf experience of more than 10 years and play golf at least once a month at present) hit balls by using the golf clubs of examples and comparative example. Each of the golf players hit five balls using each of the clubs and conducted sensuous evaluation of each of the clubs in terms of easiness of swing and vibration absorptivity at five stages of a scale of one to five. A club thought to have higher vibration absorptivity provides a higher score. The average of the scores is shown in the following Table 1 (Table 1-1 and Table 1-2).
As shown in Table 1, examples are highly evaluated as compared with comparative examples. From the evaluation results, the advantages of the present invention are apparent.
The invention described above can be applied to all golf clubs. The present invention can be used for a wood type golf club, an iron type golf club, and a putter club or the like.
The description hereinabove is merely for an illustrative example, and various modifications can be made in the scope not to depart from the principles of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-290617 | Dec 2010 | JP | national |
