Title:
SKI HAVING A HARD TYPE FOAMED RESIN CORE
United States Patent 3722901
Abstract:
In a ski including a core structure made of a hard type foamed resin, the core structure is further composed of a screw-holding framework embedded in the hard type plastic foam core body, the framework being beforehand molded to have two longitudinally extending portions for holding screws attaching steel edges of the ski to the body of the ski and a central portion for holding screws attaching a shoe clamping device for the ski to the upper surface of the ski, whereby the holding nature of the ski for these screws is substantially improved and the lateral cracks caused in the conventional ski can be completely eliminated.
Application Number:
05/113863
Publication Date:
03/27/1973
Filing Date:
02/09/1971
View Patent Images:
Export Citation:
Assignee:
Nippon Gakki Seizo Kabushiki Kaisha (Hamamatsu-shi, Shizuoka-ken, JA)
Primary Class:
International Classes:
A63C5/06; A63C5/12; A63C5/12
Field of Search:
280/11.13
Primary Examiner:
Betts, Kenneth H.
Assistant Examiner:
Smith, Milton L.
Claims:
What is claimed is
1. A ski of a laminated construction comprising: a core body of a hard type plastic foam conforming substantially to the shape of the ski; and a screw-holding framework embedded in said core body, said framework having two portions longitudinally extended along a substantial length of the ski and serving for firmly seizing screws attaching steel edges to the ski wherein said two portions are provided with rising-up wall portions respectively at their laterally outward edges, and the height of the rising-up wall portions conform with the thickness distribution of the ski along its length, and a central portion serving for firmly seizing screws attaching a shoe clamping device to the ski.
2. A ski as defined in claim 1 wherein said framework is moulded of a synthetic resin so as to form said two portions and said central portion in an integral manner.
3. A ski as defined in claim 1 wherein said two portions are so constructed that the distance between the both outward edges thereof is varied in accordance with the lateral width of the ski along its length.
4. A ski as defined in claim 1 wherein said central portion serving for firmly seizing screws attaching a shoe clamping device to the ski has a height conforming to the thickness distribution of the ski along its lengthwise direction.
5. A ski as defined in claim 1 wherein said central portion further includes a peripheral wall connecting said central portion to said two longitudinally extending portions, said peripheral wall having a number of holes perforated therein.
6. A ski as defined in claim 1 wherein said screw-holding framework has a central cross-sectional configuration of a trapezoid having no bottom.
7. A ski as defined in claim 1 wherein the rising-up wall portions of the said two longitudinally extending portions of said framework are the side surface plates of the ski.
8. A ski of a laminated construction comprising: a core body of a hard type plastic foam conforming substantially to the shape of the ski; and a screw-holding framework embedded in said core body, said framework having two portions longitudinally extended along a substantial length of the ski and serving for firmly seizing screws attaching steel edges to the ski, wherein said two portions are so constructed that the distance between the outward edges thereof is varied in accordance with the lateral width of the ski along its length; and said two portions are further provided with rising-up wall portions respectively at their laterally outward edges, and the height of the rising-up wall portions conform with the thickness distribution of the ski along its length, and a central portion serving for firmly seizing screws attaching a shoe clamping device to the ski.
1. A ski of a laminated construction comprising: a core body of a hard type plastic foam conforming substantially to the shape of the ski; and a screw-holding framework embedded in said core body, said framework having two portions longitudinally extended along a substantial length of the ski and serving for firmly seizing screws attaching steel edges to the ski wherein said two portions are provided with rising-up wall portions respectively at their laterally outward edges, and the height of the rising-up wall portions conform with the thickness distribution of the ski along its length, and a central portion serving for firmly seizing screws attaching a shoe clamping device to the ski.
2. A ski as defined in claim 1 wherein said framework is moulded of a synthetic resin so as to form said two portions and said central portion in an integral manner.
3. A ski as defined in claim 1 wherein said two portions are so constructed that the distance between the both outward edges thereof is varied in accordance with the lateral width of the ski along its length.
4. A ski as defined in claim 1 wherein said central portion serving for firmly seizing screws attaching a shoe clamping device to the ski has a height conforming to the thickness distribution of the ski along its lengthwise direction.
5. A ski as defined in claim 1 wherein said central portion further includes a peripheral wall connecting said central portion to said two longitudinally extending portions, said peripheral wall having a number of holes perforated therein.
6. A ski as defined in claim 1 wherein said screw-holding framework has a central cross-sectional configuration of a trapezoid having no bottom.
7. A ski as defined in claim 1 wherein the rising-up wall portions of the said two longitudinally extending portions of said framework are the side surface plates of the ski.
8. A ski of a laminated construction comprising: a core body of a hard type plastic foam conforming substantially to the shape of the ski; and a screw-holding framework embedded in said core body, said framework having two portions longitudinally extended along a substantial length of the ski and serving for firmly seizing screws attaching steel edges to the ski, wherein said two portions are so constructed that the distance between the outward edges thereof is varied in accordance with the lateral width of the ski along its length; and said two portions are further provided with rising-up wall portions respectively at their laterally outward edges, and the height of the rising-up wall portions conform with the thickness distribution of the ski along its length, and a central portion serving for firmly seizing screws attaching a shoe clamping device to the ski.
Description:
BACKGROUND OF THE INVENTION
This invention relates generally to ski, and more particularly to an improved construction of ski including a core structure made of a hard type foamed resin, wherein a sufficient shearing strength and firm seizure of shoe clamping device and steel edges thereto are nevertheless assured.
Heretofore, core structure of ski has been made of wood. However, because of recent difficulty in acquiring wood material of good quality and also from the viewpoint of rendering uniformity in the products and easiness in forming the core structure, intense study has been conducted on the core structure made of a hard type foamed resin or plastic foam material and various types of ski employing such core structure have been developed. Although most of the types of ski have possessed certain advantageous features, it was found that the ski having a core structure made of a hard type foamed resin had a fundamental drawback in its low shearing strngth and difficulty in fixing the shoe clamping device and steel edges firmly. More specifically, the core structure made of a hard foamed resin has had inner portions wherein the plastic foam structure is much coarser than that of the surface skin portions, whereby the seizing force for screws employed for fixing the shoe clamping device and steel edges to the body of the ski has been extremely weak, thus causing the screws to be loosened so that the shoe clamping device and steel edges tend to be fallen down. Furthermore, because of the coarse inner structure, the shearing strength of the core structure has been low especially at the central thick portion of the ski, thus rendering a high possibility of transversal cracks created at that portion of the ski.
SUMMARY OF THE INVENTION
Therefore, a primary object of the present invention is to provide a ski including a core structure made of a foamed resin or plastic foam whereby the employment of the conventional wood core member is made utterly unnecessary.
Another object of the present invention is to provide a ski including a core structure made of a foamed resin, which is simple in construction and economical in cost.
Still another object of the invention is to provide a ski including a core structure made of a foamed resin, which is well adapted to the mass-production and uniformity of the products is thereby assured.
A further object of the invention is to provide a ski including a core structure made of a foamed resin, wherein the possibility of causing the conventional transversal cracks is utterly eliminated, and bending and twisting strengths thereof are substantially improved.
A further important object of the present invention is to provide a ski including a core structure made of a foamed resin, wherein seizing or holding nature for screws, which are used for attaching a shoe clamping device and steel edges to the ski, is substantially improved.
These and other objects of the present invention can be achieved by an improved construction of ski including a core structure made of a foamed resin, wherein the core structure further comprises a core body of a hard type plastic foam conforming substantially to the shape of the ski, and a screw-holding framework embedded in the foamed resin core body in an integral manner, the framework being beforehand molded to have two longitudinally extending portions for holding screws for attaching steel edges of the ski and a central portion for holding screws for attaching a shoe clamping device for the ski, a cross-sectional configuration of the framework being a trapezoid having no bottom.
The nature, principle, and utility of the invention will be more clearly understood from the following detailed description with respect to preferred embodiments thereof when read in conjunction with the accompanying drawings wherein like parts are designated by like reference numerals.
BRIEF DESCRIPTION OF DRAWINGS
In the drawings:
FIG. 1 is a perspective view of an example of a screw-holding framework which is employed in a ski according to the present invention;
FIG. 2 is a perspective view showing another example of the screw-holding framework;
FIG. 3 is a perspective view of a core structure, partly in section, of a ski according to the present invention wherein the framework shown in FIG. 1 is employed; and
FIG. 4 is a sectional view of an example of ski in accordance with the present invention taken along a transverse plane passing through the central portion of the ski over which a shoe clamping device therefor is to be attached.
DETAILED DESCRIPTION
Referring to FIG. 1, there is indicated an example of screw-holding framework 1 made of, for instance, acrylonitrile-butadiene-styrene or ABS resin and employed for constructing a core structure of a ski according to the present invention. The rigid framework 1 is beforehand molded into an integral member having two portions 2, 2 extended along the length of the ski for holding screws which are employed for attaching steel edges of the ski on both sides of the lower surface of the ski and a central portion 3 extended along a length a of the framework 1 for holding screws which are employed for attaching a shoe clamping device on the upper surface of the approximately central portion of the ski. The width of the framework 1, measured from one laterally outward edge to another laterally outward edge thereof, is determined to conform with the planar configuration of the ski, and the width of each of the two portions 2, 2 is selected to a certain value adapted to reinforce the portions of the core structure underlying the steel edges. Furthermore, the height of the central portion 3 from the bottom of the portion 2 to the top of the central portion 3 is so distributed as to conform with the thickness distribution of the ski along its central portion, and a cross-sectional configuration of the framework 1 through the central portion is so configurated that it conforms with a trapezoid having no bottom side. The central portion 3 of the framework 1 has a plurality of holes 5, 5, . . . formed, in its molding stage, in its sloping peripheral wall 3' so that molten foamable resin can flow into the inside cavity of the central portion 3 of the framework 1 through these holes 5, 5, . . .
FIG. 2 shows another example of the framework 1 which is also employed in the construction of the core structure of a ski according to the present invention. In this example, the two portions 2, 2 for holding screws employed for attaching steel edges of the ski are further provided with rising-up wall portions 2', 2' respectively at their laterally outward edges, and the heights of the rising-up wall portions 2', 2' are so determined as to conform with the thickness distribution of the ski.
In FIG. 3, there is indicated a core structure A which is so constructed that the framework 1 indicated in FIG. 1 is embedded in a core body 4 of a hard type foamed resin or plstic foam, such as polyurethane, polyester or epoxy foam, with the upper surface of the central portion 3 of the framework 1 employed for firmly holding screws for shoe clamping device (not shown) being exposed upwardly. The core body 4 is so formed as to substantially conform to the shape of the ski.
In FIG. 4, which is a sectional view of an example of ski in accordance with the present invention taken along a transverse plane passing through the central portion of the ski over which a shoe clamping device is to be attached, there is indicated a ski main body B comprises a core structure as shown in FIG. 3 further attached with an upper surface plate 10, a lower surface plate 11, side surface plates 12, 12, a sliding surface or sole plate 13, an upper surface decorative plate 14, and top edges 15, 15. On the ski main body B thus formed, a shoe clamping plate 6 forming one part of the shoe clamping device (not shown) is attached by means of screws 7, 7, . . . , and steel edges 8, 8 are also attached by means of screws 9, 9, . . . .
As is apparent from the above description, the ski main body B includes, as its principal component, a core structure A comprising a core body 4 of a hard type foamed resin or plastic foam and a screw-holding framework 1 having as its integral parts two longitudinally extending portions 2, 2 and a central portion 3 embedded in the core body of hard type foamed resin 4 which, during the molding operation, is injected around the framework 1 placed in a metal mold, so as to form an integral core structure A. When a shoe clamping device is attached to the central portion of the ski main body B by means of the screws 7, 7, . . . , the screws are firmly seized by the central portion 3 of the screw-holding framework 1, and the screws 9, 9, . . . employed for attaching steel edges 8, 8 are firmly seized by the two longitudinally extending portions 2, 2 of the framework 1, whereby the screw holding strengths of the ski main body B can be substantially improved. Furthermore, the peripheral side portion 3' of the central portion 3 withstands against the shearing force acting on the core structure at lengthwisely central portion thereof, whereby the transversal cracks frequently caused in the conventional ski having a foamed resin core structure can be substantially eliminated. In addition, any force acting, for instance, to loosen the screws 7, 7, . . . for attaching the shoe clamping device is transmitted to the longitudinally extending steel-edge supporting portions 2, 2 of the framework 1, whereby the separation of the laminated members in the ski main body can be prevented and the bending strength and twisting strength of the ski main body can be substantially elevated.
In the case where the laterally outward edges of the two longitudinally extended portions 2, 2 of the framework 1 are raised-up as shown in FIG. 2 so that the height thereof conforms with the thickness distribution of the ski, the raised-up walls 2', 2' can also be employed as the side surface plates as designated by 12, 12 in FIG. 4, whereby the advantageous feature of the core structure is further extended.
This invention relates generally to ski, and more particularly to an improved construction of ski including a core structure made of a hard type foamed resin, wherein a sufficient shearing strength and firm seizure of shoe clamping device and steel edges thereto are nevertheless assured.
Heretofore, core structure of ski has been made of wood. However, because of recent difficulty in acquiring wood material of good quality and also from the viewpoint of rendering uniformity in the products and easiness in forming the core structure, intense study has been conducted on the core structure made of a hard type foamed resin or plastic foam material and various types of ski employing such core structure have been developed. Although most of the types of ski have possessed certain advantageous features, it was found that the ski having a core structure made of a hard type foamed resin had a fundamental drawback in its low shearing strngth and difficulty in fixing the shoe clamping device and steel edges firmly. More specifically, the core structure made of a hard foamed resin has had inner portions wherein the plastic foam structure is much coarser than that of the surface skin portions, whereby the seizing force for screws employed for fixing the shoe clamping device and steel edges to the body of the ski has been extremely weak, thus causing the screws to be loosened so that the shoe clamping device and steel edges tend to be fallen down. Furthermore, because of the coarse inner structure, the shearing strength of the core structure has been low especially at the central thick portion of the ski, thus rendering a high possibility of transversal cracks created at that portion of the ski.
SUMMARY OF THE INVENTION
Therefore, a primary object of the present invention is to provide a ski including a core structure made of a foamed resin or plastic foam whereby the employment of the conventional wood core member is made utterly unnecessary.
Another object of the present invention is to provide a ski including a core structure made of a foamed resin, which is simple in construction and economical in cost.
Still another object of the invention is to provide a ski including a core structure made of a foamed resin, which is well adapted to the mass-production and uniformity of the products is thereby assured.
A further object of the invention is to provide a ski including a core structure made of a foamed resin, wherein the possibility of causing the conventional transversal cracks is utterly eliminated, and bending and twisting strengths thereof are substantially improved.
A further important object of the present invention is to provide a ski including a core structure made of a foamed resin, wherein seizing or holding nature for screws, which are used for attaching a shoe clamping device and steel edges to the ski, is substantially improved.
These and other objects of the present invention can be achieved by an improved construction of ski including a core structure made of a foamed resin, wherein the core structure further comprises a core body of a hard type plastic foam conforming substantially to the shape of the ski, and a screw-holding framework embedded in the foamed resin core body in an integral manner, the framework being beforehand molded to have two longitudinally extending portions for holding screws for attaching steel edges of the ski and a central portion for holding screws for attaching a shoe clamping device for the ski, a cross-sectional configuration of the framework being a trapezoid having no bottom.
The nature, principle, and utility of the invention will be more clearly understood from the following detailed description with respect to preferred embodiments thereof when read in conjunction with the accompanying drawings wherein like parts are designated by like reference numerals.
BRIEF DESCRIPTION OF DRAWINGS
In the drawings:
FIG. 1 is a perspective view of an example of a screw-holding framework which is employed in a ski according to the present invention;
FIG. 2 is a perspective view showing another example of the screw-holding framework;
FIG. 3 is a perspective view of a core structure, partly in section, of a ski according to the present invention wherein the framework shown in FIG. 1 is employed; and
FIG. 4 is a sectional view of an example of ski in accordance with the present invention taken along a transverse plane passing through the central portion of the ski over which a shoe clamping device therefor is to be attached.
DETAILED DESCRIPTION
Referring to FIG. 1, there is indicated an example of screw-holding framework 1 made of, for instance, acrylonitrile-butadiene-styrene or ABS resin and employed for constructing a core structure of a ski according to the present invention. The rigid framework 1 is beforehand molded into an integral member having two portions 2, 2 extended along the length of the ski for holding screws which are employed for attaching steel edges of the ski on both sides of the lower surface of the ski and a central portion 3 extended along a length a of the framework 1 for holding screws which are employed for attaching a shoe clamping device on the upper surface of the approximately central portion of the ski. The width of the framework 1, measured from one laterally outward edge to another laterally outward edge thereof, is determined to conform with the planar configuration of the ski, and the width of each of the two portions 2, 2 is selected to a certain value adapted to reinforce the portions of the core structure underlying the steel edges. Furthermore, the height of the central portion 3 from the bottom of the portion 2 to the top of the central portion 3 is so distributed as to conform with the thickness distribution of the ski along its central portion, and a cross-sectional configuration of the framework 1 through the central portion is so configurated that it conforms with a trapezoid having no bottom side. The central portion 3 of the framework 1 has a plurality of holes 5, 5, . . . formed, in its molding stage, in its sloping peripheral wall 3' so that molten foamable resin can flow into the inside cavity of the central portion 3 of the framework 1 through these holes 5, 5, . . .
FIG. 2 shows another example of the framework 1 which is also employed in the construction of the core structure of a ski according to the present invention. In this example, the two portions 2, 2 for holding screws employed for attaching steel edges of the ski are further provided with rising-up wall portions 2', 2' respectively at their laterally outward edges, and the heights of the rising-up wall portions 2', 2' are so determined as to conform with the thickness distribution of the ski.
In FIG. 3, there is indicated a core structure A which is so constructed that the framework 1 indicated in FIG. 1 is embedded in a core body 4 of a hard type foamed resin or plstic foam, such as polyurethane, polyester or epoxy foam, with the upper surface of the central portion 3 of the framework 1 employed for firmly holding screws for shoe clamping device (not shown) being exposed upwardly. The core body 4 is so formed as to substantially conform to the shape of the ski.
In FIG. 4, which is a sectional view of an example of ski in accordance with the present invention taken along a transverse plane passing through the central portion of the ski over which a shoe clamping device is to be attached, there is indicated a ski main body B comprises a core structure as shown in FIG. 3 further attached with an upper surface plate 10, a lower surface plate 11, side surface plates 12, 12, a sliding surface or sole plate 13, an upper surface decorative plate 14, and top edges 15, 15. On the ski main body B thus formed, a shoe clamping plate 6 forming one part of the shoe clamping device (not shown) is attached by means of screws 7, 7, . . . , and steel edges 8, 8 are also attached by means of screws 9, 9, . . . .
As is apparent from the above description, the ski main body B includes, as its principal component, a core structure A comprising a core body 4 of a hard type foamed resin or plastic foam and a screw-holding framework 1 having as its integral parts two longitudinally extending portions 2, 2 and a central portion 3 embedded in the core body of hard type foamed resin 4 which, during the molding operation, is injected around the framework 1 placed in a metal mold, so as to form an integral core structure A. When a shoe clamping device is attached to the central portion of the ski main body B by means of the screws 7, 7, . . . , the screws are firmly seized by the central portion 3 of the screw-holding framework 1, and the screws 9, 9, . . . employed for attaching steel edges 8, 8 are firmly seized by the two longitudinally extending portions 2, 2 of the framework 1, whereby the screw holding strengths of the ski main body B can be substantially improved. Furthermore, the peripheral side portion 3' of the central portion 3 withstands against the shearing force acting on the core structure at lengthwisely central portion thereof, whereby the transversal cracks frequently caused in the conventional ski having a foamed resin core structure can be substantially eliminated. In addition, any force acting, for instance, to loosen the screws 7, 7, . . . for attaching the shoe clamping device is transmitted to the longitudinally extending steel-edge supporting portions 2, 2 of the framework 1, whereby the separation of the laminated members in the ski main body can be prevented and the bending strength and twisting strength of the ski main body can be substantially elevated.
In the case where the laterally outward edges of the two longitudinally extended portions 2, 2 of the framework 1 are raised-up as shown in FIG. 2 so that the height thereof conforms with the thickness distribution of the ski, the raised-up walls 2', 2' can also be employed as the side surface plates as designated by 12, 12 in FIG. 4, whereby the advantageous feature of the core structure is further extended.