Patent Application
20070238546
The embodiments of the present invention will be described below with reference to the drawings.
As shown in
The prepregs 21 through 31 constituting the shaft 10 are respectively composed of reinforcing fibers F21 through F31 made of carbon fibers impregnated with the epoxy resin. Thermosetting resin other than the epoxy resin may be used to impregnate the carbon fiber.
More specifically, the prepreg 21 is disposed at the head-side tip portion of the shaft 10 and has a length of 197 mm. The orientation angle of the reinforcing fiber F21 of the prepreg 21 is set to 0° with respect to the axis of the shaft 10.
The prepregs 22 and 23 are disposed over the full length of the shaft 10. The orientation angle of the reinforcing fiber F22 of the prepreg 22 is set to −45° with respect to the axis of the shaft 10. The orientation angle of the reinforcing fiber F23 of the prepreg 23 is set to +45° with respect to the axis of the shaft 10. The prepregs 22, 23 are wound round the shaft 10 after the prepregs 22, 23 are bonded to each other with the reinforcing fiber F22, F23 intersecting with each other to form an inner full-length bias set layer Al which will be described later.
The prepreg 24 is disposed at the head-side tip portion of the shaft 10 and has a length of 267 mm. The orientation angle of the reinforcing fiber F24 of the prepreg 24 is set to 0° with respect to the axis of the shaft 10.
The prepregs 25 and 26 are disposed over the full length of the shaft 10. The orientation angle of the reinforcing fibers F25, F26 of the prepregs 25, 26 is set to 0° with respect to the axis of the shaft 10.
The prepregs 27 and 28 are disposed over the full length of the shaft 10. The orientation angle of the reinforcing fiber F27 of the prepreg 27 and that of the reinforcing fiber F28 of the prepreg 28 are set to −45° and +45° respectively with respect to the axis of the shaft 10. The prepregs 27, 28 are wound round the shaft 10 after the prepregs 27, 28 are bonded to each other with the reinforcing fiber F27, F28 intersecting with each other to form an outer full-length bias set layer A2 which will be described later.
The prepreg 29 is disposed over the full length of the shaft 10. The orientation angle of the reinforcing fiber F29 of the prepreg 29 is set to 0° with respect to the axis of the shaft 10.
The prepreg 30 is disposed at the head-side tip portion of the shaft 10 and has a length of 217 mm. The orientation angle of the reinforcing fiber F30 of the prepreg 30 is set to 0° with respect to the axis of the shaft 10.
The prepreg 31 is disposed at the head-side tip portion of the shaft 10 and has a length of 167 mm. The orientation angle of the reinforcing fiber F31 of the prepreg 31 is set to 0° with respect to the axis of the shaft 10.
The prepregs 22, 23, 25, 26, 27, 28, and 29 of the shaft 10 form the full-length layers 41 through 47 respectively.
More specifically, as also shown in
An outer full-length bias set layer A2 consisting of the prepregs 27, 28 and an outermost full-length bias set layer B2 consisting of the prepreg 29 are disposed in an outer-layer part II including the three full-length layers 45 through 47 disposed at the peripheral side of the shaft 10. A full-length straight layer B3 consisting of the prepreg 26 is disposed in an intermediate-layer part III consisting of the full-length layer 44.
The thickness T1 of the inner bias set layer A1 and the thickness T2 of the outer bias set layer A2 are set to 0.315 mm. The thickness of each of the full-length straight layers B1 through B3 is set to 0.158 mm.
In the shaft 10 having the above-described construction, neither the number of the bias layers influencing the torque of the shaft 10 nor the weight of the prepreg per area is increased. In the conventional art, the full-length bias layer is disposed in only the inner-layer part of a shaft. But in the shaft 10, the full-length bias layer is divided into the inner full-length bias set layer A1 and the outer full-length bias set layer A2 to dispose the full-length bias layer at not only the inner-layer part I but also at the outer-layer part II so that the full-length bias layers are disposed in a favorable balance. Therefore it is possible to decrease the torque of the shaft 10 without increasing the weight thereof and without changing a desired degree of the flexure and strength thereof. Thereby the shaft 10 is allowed to have a light weight and a high strength and hit a ball a long distance in a desired direction.
Further because the outermost full-length bias set layer B2 is formed on the periphery of the outer full-length bias set layer A2, it is possible to prevent the outer full-length bias set layer A2 from being adversely affected by the polishing of the surface of the shaft 10 necessary to be done before the surface thereof is painted. Thus the outermost full-length bias set layer B2 is capable of sufficiently displaying the effect of decreasing the torque.
The orientation angle of the reinforcing fibers F22, F23, F27, and F28 of the full-length bias set layers A1 and A2 with respect to the axis of the shaft 10 is set to +45° or −45° which are in the range from not less than ±25° to nor more than ±65°. Thus the full-length bias set layers A1 and A2 are capable of sufficiently displaying the torque-decreasing effect and enhancing the strength of the shaft in each of the bending direction and crushing direction thereof in a favorable balance.
The golf club shafts of examples 1 through 11 of the present invention and those of comparison examples 1 through 5 are described below in detail.
As shown in table 1, the golf club shafts of the examples 1 through 11 of the present invention and those of comparison examples 1 through 5 were made by differentiating the fibrous angles (the orientation angle of the reinforcing fiber with respect to the axis of the shaft) and thicknesses of the full-length layers 41 through 47 from one another respectively to measure the grip-side flexure, torque, three-point bending strength, and crushing strength thereof. Tables 1 and 2 show the results.
11 prepregs used for each of the golf club shafts of the examples 1 through 11 of the present invention and the comparison examples 1 through 5 were produced by Mitsubishi Rayon Co., Ltd. Each of the 11 prepregs was composed of carbon fibers used as the reinforcing fibers thereof and epoxy resin with which the carbon fibers were impregnated. The prepregs were formed by the sheet winding method as in the case of the first embodiment. The prepregs having article numbers used in the examples and the comparison examples were produced by Mitsubishi Rayon Co., Ltd., as described above.
Any of the shafts of the examples 1 through 11 and the comparison example 1 through 5 had a length of 1195 mm. The layered position of the seven full-length layers 41 through 47 formed over the full length of the shaft and the construction of the partial reinforcing layers formed at a part of the shaft were identical to those of the first embodiment. Table 1 shows the detail of only the full-length layers 41 through 47.
The weight of the shaft of each of the examples and the comparison example and the shaft balance thereof were set as shown in table 1.
The golf club shaft of the example 1 had the same construction as that of the shaft of the first embodiment. More specifically, the full-length layers 41 and 42 were formed as the inner full-length bias set layer A1 having a fibrous angle of −45° and +45° and a thickness of 0.315 mm respectively. The full-length layers 43 and 44 were formed as the straight layers Bi and B3 having a fibrous angle of 0° and a thickness of 0.158 mm respectively. The full-length layers 45 and 46 were formed as the outer full-length bias set layers A2 having a fibrous angle of −45° and +45° and a thickness of 0.315 mm respectively. The full-length layer 47 was formed as the outermost straight layer B2 having a fibrous angle of 0° and a thickness of 0.158 mm.
The inner bias set layer A1 was disposed in the inner-layer part I, whereas the outer bias set layer A2 was disposed in the outer-layer part II. The ratio of the fibrous angle 02 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias-set layer A1 was set to 1.00. The ratio of the thickness T2 of the outer bias set layer A2 to the thickness T1 of the inner bias set layer A1 was also set to 1.00.
A prepreg having an article number “MR350C-125S” was used as any of the full-length layers 41 through 47.
As the full-length layers 41, 42 constituting the inner full-length bias set layer Al, a prepreg having an article number “MR350C-100S” was used. The thickness of the inner full-length bias set layer A1 was set to 0.2625 mm. As the full-length layers 45 and 46 constituting the outer full-length bias set layer A2, a prepreg having an article number “MR350C-150S” was used. The thickness of the outer full-length bias set layer A2 was set to 0.3675 mm. The ratio of the thickness T2 of the outer full-length bias set layer A2 to the thickness T1 of the inner full-length bias set layer A1 was set to 1.4. The fibrous angle and other constructions of the shaft of the example 2 were set identically to those of the example 1.
As the full-length layers 41, 42 constituting the inner full-length bias set layer A1, a prepreg having the article number “MR350C-150S” was used. The thickness of the inner full-length bias set layer A1 was set to 0.3675 mm. As the full-length layers 45 and 46 constituting the outer full-length bias set layer A2, a prepreg having the article number “MR350C-100S” was used. The thickness of the outer full-length bias set layer A2 was set to 0.2625 mm. The ratio of the thickness T2 of the outer full-length bias set layer A2 to the thickness T1 of the inner full-length bias set layer A1 was set to 0.71. The fibrous angle and other constructions of the shaft of the example 3 were set identically to those of the example 1.
As the full-length layers 41, 42 constituting the inner full-length bias set layer A1, a prepreg having an article number “MR350C-075S” was used. The thickness of the inner full-length bias set layer A1 was set to 0.21 mm. As the full-length layers 45 and 46 constituting the outer full-length bias set layer A2, a prepreg having an article number “MR350C-175S” was used. The thickness of the outer full-length bias set layer A2 was set to 0.42 mm. The ratio of the thickness T2 of the outer full-length bias set layer A2 to the thickness T1 of the inner full-length bias set layer A1 was set to 2. The fibrous angle and other constructions of the shaft of the example 4 were set identically to those of the example 1.
As the full-length layers 41, 42 constituting the inner full-length bias set layer A1, a prepreg having the article number “MR350C-150S” was used. The thickness of the inner full-length bias set layer A1 was set to 0.3675 mm. As the full-length layers 45 and 46 constituting the outer full-length bias set layer A2, a prepreg having the article number “MR350C-175S” was used. The thickness of the outer full-length bias set layer A2 was set to 0.42 mm. The ratio of the thickness T2 of the outer full-length bias set layer A2 to the thickness T1 of the inner full-length bias set layer A1 was set to 1.1. The fibrous angle and other constructions of the shaft of the example 5 were set identically to those of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −30° and +30° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were also set to −30° and +30° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 1.00. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −60° and +60° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were also set to −60° and +60° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 1.00. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −30° and +30° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were set to −60° and +60° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 2. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −30° and +30° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were set to −45° and +45° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 1.5. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −45° and +45° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were set to −60° and +60° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 1.33. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
As shown in
As shown in
The kind of the prepreg composing each layer was set identically-to that of the example 1.
As shown in
The kind of the prepreg composing each layer was set identically to that of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −15° and +15° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were also set to −15° and +15° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 1.00. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −75° and +75° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were also set to −75° and +75° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 1.00. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
The fibrous angles of the full-length layers 41, 42 constituting the inner full-length bias set layer A1 were set to −15° and +15° respectively. The fibrous angles of the full-length layers 45 and 46 constituting the outer full-length bias set layer A2 were also set to −75° and +75° respectively. The ratio of the fibrous angle θ2 of the outer bias set layer A2 to the fibrous angle θ1 of the inner bias set layer A1 was set to 5.00. The thickness of each layer was set equally to that of the example 1. The kind of the prepregs and other constructions were set identically to those of the example 1.
The grip-side flexure is an index of the hardness of the shaft 10 at its grip side. As shown in
As shown in
The three-point bending strength means a breaking strength provided by the Product Safety Association. As shown in
To measure the crushing strength of each shaft 10, by using a utility compression testing machine, a compressive test was conducted by forming a specimen having a length of about 10 mm, with the center thereof disposed at positions of 10 mm, 100 mm, 200 mm, and 300 mm from the grip-side butt 12 of the shaft 10.
It could be confirmed from table 1 that the shafts of the examples 1 through 11 had a low torque and a desired degree of flexure and strength because in the shafts, the full-length bias layers were disposed in the inner-layer part I and the outer-layer part II in a favorable balance.
It was confirmed that the shaft of the comparison example 1 in which the full-length bias layers was disposed in only the inner-layer part I had a large torque. It was also confirmed that the shaft of the comparison example 2 in which the full-length bias layers was disposed in only the outer-layer part II had a low torque, but had an excessive degree of flexure and further a low bending strength and crushing strength.
The shaft of the comparison example 3 in which the fibrous angle of the bias layer was set below ±25° and the shaft of the comparison example 4 in which the fibrous angle of the bias layer was set above +65° did not have a low torque and in addition had a low strength, although the ratio of the fibrous angle θ2 of the outer bias set layer to the fibrous angle θ1 of the inner bias set layer was set to 1.
It was confirmed that the shaft of the comparison example 5 in which the ratio of the fibrous angle θ2 of the outer bias set layer to the fibrous angle θ1 of the inner bias set layer was more than 2 had a large torque and an excessively large flexure.
The torque was low and the flexure degree was not high in the shaft of the examples 1 through 7 and 11 in which the ratio of the fibrous angle θ2 of the outer bias set layer to the fibrous angle θ1 of the inner bias set layer was 1.00 and the shaft of the examples 8, 9, and 10 in which the ratio of the fibrous angle θ2 of the outer bias set layer to the fibrous angle θ1 of the inner bias set layer was more than 1 not more than 2. The shafts of the examples 8, 9, and 10 were higher than those of the examples 1 through 7 and 11 in the crushing strengths thereof.
The shaft of the example 4 in which the ratio of the thickness T2 of the outer full-length bias set layer to the thickness T1 of the inner full-length bias set layer was larger than 1.4 had a much higher flexure degree than the shafts of the examples 1, 2, and 5 and a lower bending strength than the shafts of the examples 1, 2, and 5.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-108305 | Apr 2006 | JP | national |
