US3628802A

US3628802A - Fiber reinforced plastic ski and method of making the same

Info

Publication number: US3628802A
Application number: US877284A
Authority: US
Inventors: Osamu Hashimoto; Nobuyuki Kawai
Original assignee: Nippon Gakki Co Ltd
Current assignee: Nippon Gakki Co Ltd
Priority date: 1968-11-21
Filing date: 1969-11-17
Publication date: 1971-12-21
Anticipated expiration: 1988-12-21
Also published as: JPS5116819B1

Abstract

A fiber-reinforced plastic ski comprising a body and an upper plate joined to form inside cavities, said body being constructed by integrally molding a baseplate of laminated FRP materials, right and left side members of the same material, at least one reinforcing rib of the same materials rising from the baseplate and having the same height as said side members, running edges located on the lower surface of the baseplate at both sides thereof and a running surface member interposed between running edges on the lower surface of the baseplate, and said upper plate consisting of laminated FRP materials and having top edges embedded in its upper surface at both sides thereof.

Description

United States Patent Inventors Ola-u Ilnhlnoto;

3,322,435 5/1967 Kirschner 280/11.13 LM g -y Klmi, both ollhmmw-lhi, 3,503,621 3/1970 Schmidt et a1. 280/11.13 LB up l 1 pp No. 871,2 145 2 FOREIG N PATENTS [22] Filed Nov. 17,1969 13 4/1936 Austria 280/11.13 LB Patented Dec. 21 971 572,337 3/1959 Canada 280/11-13 LB [73] Assignec "WM s Kbmikl n, 734,828 5/1966 Canada 280/1 1.13 LB mm-Mdbhm 1,453,516 8/1966 France 280/11.13 LB [32] Priority ND 2 [968 188,873 11/1966 U.S.S.R. 280/1 1.13 L l" Primary Examiner-Milton Buchler 1 43/85489 Assistant Examiner-Paul E. Sauherer Attorney-Ostrolenk, Faber, Gerb & Sotfen [54] "BER REINFORCED PLASTIC AND METHOD ABSTRACT: A fiber-reinforced plastic ski comprising a body o MAKING 11 SAM]; and an upper plate oined to form inside cavities, said body 6 u 14 Drwing pigs being constructed by integrally molding a baseplate of I laminated FRP materials, right and left side members of the [52] 1.1.5. C1- ISO/11.13 L same material at least one reinforcing rib of the same materb 1 Int-CL 1 als rising from the baseplate and having the same height as O id me b r run ing dge located on the lower surface l L21 1 M; 9/310 6 of the baseplate at both sides thereof and a running surface member interposed between running edges on the lower sur- [56] Rd'nnm cued face of the baseplate, and said upper plate consisting of UNlTED STATES PATENTS laminated FRP materials and having top edges embedded in 3.074.732 1/1963 Riha 280/1 1.13 M its upper surface at both sides thereof.

l 1 g\\ 9 fi/ 9 l memes) m2] mi SHEET 1 [1F 4 9 W 7 g n w Osmu Hashimotb Nobuyuki Kawai INVENTORS PAIENIEMzm an 3628.802

' SHEET 2 OF 4 Osamu' Hashimoto Nobuyuki Ka wa i INVENTORS alszelaoz' PATENTED BEBE! M SHEET 3 BF 4 Osamu Hashimoto; Nobuyuki Kawai INVENTORS Array/vin- FIBER REINFORCED PLASTIC SKI AND METHOD OF MAKING THE SAME This invention relates to a fiber-reinforced plastic ski (hereinafter referred to as an FRP ski) to be formed in a metal mold and method or process of making the same which is characterized particularly in the technique of precisely locating and securing top and running edges.

FRP skis according to the prior art have mostly been either of sandwich construction consisting of FRP plates laminated and molded on the upper and lower surfaces of a core of wood or the like, or of wrapped construction consisting of FRP plates laminated and molded so as to wrap a core. However, these constructions have proven disadvantageous, because they require aftertreatments such as cutting of sidewalls of the ski and bonding of side members thereto or fixing of steel edges, top edges and other portions by screws or bonding of running surface member. Another disadvantage is that cores to be used in these constructions are complicated in shape, difficult in machining and low in productivity.

While the contour of a ski according to the above-mentioned methods is made utilizing a core as a basic component thereof and laminating and molding FRP plates around the core, there has been a technical idea of providing the contour of a ski without utilizing a core as a basic component but by press-forming in a mold. However, in this technique is used a core material of foamed substance which though its contour is simple as compared with the aforementioned core of wood is not always easy to manufacture as its section varies and, moreover, requires aftertreatment of fastening steel edges and top edges with the aid of screws after molding.

Furthermore, skis according to another method are made forming hard polyethylene sheet provided with metal edges and thereafter wrapping plies of glass fiber impregnated with synthetic resin around a core of foam plastics or natural cork, the running surface member, left and right side members and the ski body being separately formed and then integrally shaped in a mold.

Furthermore, the body of a ski according to still another method is molded placing in a mold a hollow member around which is wrapped a cloth of glass fiber impregnated with thermosetting resin and making the hollow member inflated to cause the material to be pressed and thereby closely attached to the inner wall of the mold, the running baseplate in which steel edges are embedded being separately formed and thereafter bonded to the ski body.

All the above-mentioned FRP skis are fabricated in a manner whereby the running surface member and other parts are formed separately and thereafter integrally shaped in a mold.

Moreover, running edges are either embedded when forming running surface member or secured by screws or the like after molding the ski body.

Skis on the body of which running edges are fastened by screws have many disadvantages. They have a low bonding strength because of concentration of stresses onto those portions of edges which are fastened by screws, are low in vibration and water resisting properties and, furthermore, require much time in mounting of edges.

The present invention has for its object to provide an FRP ski free from all the above-described defects and at the same time ensuring its mass production and high durability, and relates to an FRP ski and method of producing the same wherein a body and an upper plate are joined to form inside space; said body being constructed by integrally molding a baseplate of compressed laminated FRP materials, right and left side members of the same material, reinforcing ribs of the same material rising from the baseplate, having the same height as said side members and locating therebetween, running edges located on the lower surface of baseplate at both sides thereof, and a running surface member interposed between a pair of running edges on the lower surface of baseplate; and said upper plate consisting of a compressed laminated FRP plate and having top edges embedded in its upper surface at both sides thereof;

whereby the above-mentioned defects inherent in prior articles can be eliminated.

Various embodiments of this invention are illustrated in the accompanying drawings, wherein:

FIG. 1 is a side view in longitudinal cross section, taken on the line I-I of FIG. 2, constructed according to this invention;

FIG. 2 is a transverse sectional view taken on the line ll-ll of FIG. I;-

FIG. 3 is a transverse sectional view taken on the line III- III of FIG. 1; I

FIG. 4 is a transverse sectional view taken on the line IV-- IV of FIG. 1;

FIGS. 5, 6, and 7 are sectional views of a ski in a mold illustrating a method of producing a ski according to the invention;

FIGS. 8 and 9 are perspective views of edge retainers;

FIG. 10 and FIG. 1] are plan views showing methods of retaining running edges;

FIG. 12 is a sectional view taken on the line XIIXII of FIG. I I; and

FIGS. 13 and 14 are perspective sectional views of other embodiments of the skis of the present invention.

Referring to the accompanying drawings, a ski of this invention consists fundamentally of a ski body I and an upper plate 2. The body 1 is constructed by integrally forming the following components in a mold; a baseplate 3 of compressed laminated FRP sheetlike materials, both side members 4 of the same materials, a reinforcing rib 5 of the same material rising from the baseplate 3 and having the same height as said side members and locating therebetween, running edges 6 located on the lower portion of baseplate 3 at both sides thereof and running surface member 7 interposed between running edges 6 on the lower surface of the baseplate 3.

In the embodiment shown in the accompanying FIGS. 2 to 6, only one reinforcing rib 5 is provided in longitudinal direction of the ski but it is allowed to have a plurality of reinforcing ribs as shown in FIG. 13, to provide a reinforcing rib running zigzag in longitudinal direction of the ski as shown in FIG. 14, or to place reinforcing ribs obliquely crossed each other or to have combinations thereof.

According to this invention, usable materials for the running surface member 7 are selected from suitable synthetic resin plates or sheets made of polyethylene, polyethylene tetrafluoride the like but it 'is desirable that its surface in contact with the baseplate 3 is provided with laminated woven cloth or subjected to oxidation treatment or treatment by oxidizing flame for better adhesion.

Next the upper plate 2 is a plate made of molded laminated FRP sheetlike materials and having top edges 8 embedded in the upper surface at both sides thereof.

For top edges to be used in this invention it is desirable to utilize a punched metal strip of aluminum alloy. Top edges 8 may be exposed on the upper surface of upper plate 2 or ar ranged slightly inside the upper surface.

By joining the ski body 1 and upper plate 2 thus constructed, an FRP ski containing cavities 9 is completed. It is to be pointed out that the provision of blocks 10 of wood or the like to be attached with the aid of adhesive in cavities 9 in the center portion of the ski is for the purpose of fastening the boots bindings by wood screws.

An FRP ski according to this invention is constructed as mentioned above in detail. By reason of the use of compressed laminated FRP sheetlike materials and of their form and construction which permit to apply sufficiently high forming pressure, it is possible to form, in a mold by compression molding, FRP skis having stable shape and strength and not requiring aftertreatment. Moreover, at the same time it is possible to integrally join running edges, top edges and running surface member for which very high joining strength is required.

The both side members 4 and the reinforcing rib 5 are formed integrally with the baseplate 3 and the running surface member 7, and said baseplate 3 is reinforced by the three members, i.e. both side members and a reinforcing rib which are provided in the longitudinal direction of the ski body. Ac-

cordingly, it is possible to produce skis with constant camber, high durability and good skiing properties.

Further, it is possible to provide a desirable ski of anyone's choice by changing partial thickness of the ski and distribution of flexibility without any changes of the camber and durability thereof.

In addition to that, the upper surface of the reinforcing rib is on the same level with those of the side members 4 as they have the same heights, accordingly, the upper plate 2 can be joined easily without using any adjusting pieces, and the trimming of the above three for adjusting the distribution of flexibility can be carried out at a time. Therefore, the ski of the present invention is suitable for mass production. Furthermore, it is possible to produce FRP skis at low cost because core materials complicated in shape and difficult to manufacture are not required. Furthermore, FRP skis according to this invention have the additional effect of reduced weight because they possess cavities in place of core material and the provision of a reinforcing rib or ribs makes them possible to display the effect of regulated flexibility of ski bodies.

Referring now to the method of manufacturing the abovedescribed FRlP skis, the FRP sheetlike materials to be used in this invention are aggregates of fibers such as glass fiber and synthetic fiber impregnated with a polyester resin, epoxy resin or other thermosetting resins, and formed in a wet sheet or block (hereinafter referred to as prepregsheet").

The fiber aggregates may be in the form of rough-woven cloth or may consist of alternate layers of long fabrics or filaments oriented along the length of a ski and of mats of undirectional fabrics. In the latter case it is possible to use glass roving as it is, whereby the production cost can be reduced.

As mentioned above, this l- RI ski consists of the body 1 and the upper plate 2, the manufacturing methods of which will be separately given below.

The mold to be used in this invention for the ski body consists of the female section 1.1 and male section 12. The form of the space 13 to be constituted inside the mold by said sections is equal to that of the body 1. The female section 11 is provided with

projections

11a and 11b to form in the body 1, recesses to provide cavities 9. i

To construct the body 1, at first side members 4 and a reinforcing rib 5 are laminated of the prepregsheet aforementioned cut to suitable sizes by inserting a suitable number of plies of prepregsheet tapes into corresponding places inside the female section 11 of the mold, then a major portion of the baseplate 3 is laminated of multi-plied prepregsheets, placing intermittently thereupon edge retainers 14 to be mentioned later and holding and fixing running edges 6 by said retainers to outer side edges of side members 4. Next the rest portion of the baseplate 3 is laminated of the prepregsheets covering said retainers, Finally the running surface member 7 is placed on the baseplate with running edges attached at both sides thereof.

Said edge retainers 14 are designed to hold and prevent edges from being moved at the time of compression molding by laying them between edges at both sides of the baseplate. Desirable embodiments of their construction are shown in FIG. 8 and FIG. 9. The spacer 14 illustrated in FIG. 8 consists of a band plate having splits 15, each running from right or left end of the plate toward the middle part thereof in widthwise direction of the ski, and alternately raised engaging pawls 15a and 1511 at both ends so that engaging steps of edges 6 may be inserted into said splits 15 and fastened by engaging

pawls

15a and 15b in order to clip edges.

A plurality of band type spacers 14 are arranged by a suitable space from each other to maintain edges in place (FIG. 10). A holder 14 shown in FIG. 9 consists of a rectangular plate the longitudinal direction of which corresponds to that of the ski and which has splits 15', each running from one of longitudinal sides of the plate toward its middle part in widthwise direction of the ski, and engaging edges 15'a and 15'!) arranged alternately at both longitudinal sides so that engaging steps 60 of edges 6 may be inserted into said splits 15' and clipped by engaging edges 15'a and ll5'b in order to fix said edges in place (FIG. 11).

To prevent the running edges from being moved under the compression molding operation with the use of such retainers, the running surface member 7 is put in place with said retainers interposed between both edges. By compressing by the movable male section 12 of the mold, heating until the thermosetting resin of the prepregsheet is cured and taking out from the mold, the ski body 1 wherein the baseplate 3, side members 4, reinforcing rib 5, running edges 6 edge retainers and running surface member 7 are integrally molded.

By the reference numeral l6, 16 are designated separators such as woven cloths of polypropylene fabrics or glass fibers which are not adhesive to said thermosetting resins. By peeling these separators from the body 1 after forming in the mold can be obtained a rough surface which are ready for better bonding to the upper plate 2.

Forming of the upper plate 2 is essentially identical to that of the above-described ski body 1. By cutting to suitable size and inserting the prepregsheet to form the upper plate 2 into the female section 17 of the mold, inserting top edges 8 with the use of edge retainers into corresponding places on the upper surface of said plate at both sides thereof in the same way as in the case of the ski body, placing an intermediate layer 2a of said sheet thereupon, then compressing by the male section 18 of the mold, heating until the thermosetting resin is cured and taking out from the mold the upper plate 2 with embedded therein top edges 10. By the reference numeral 19 is designated a separator of a woven cloth which is not adhesive to said thermosetting resins and which corresponds to the aforementioned separator 16. Edge retainers 14 to be used are the same as in the case of the ski body. In an example illustrated top edges are fixed in the same way as shown in FIG. 11.

FRlP skis containing inside cavities therein can be produced joining thus formed ski body 1 and upper plate 2 with each other as shown in FIG. 7.

FRP skis produced according to this invention have various effects as mentioned above. In addition to this, by reason of the use of the prepregsheet in the form of wet sheet or of block consisting of an aggregate of fabrics impregnated with thermosetting resins, it is possible to simplify the operation of pilling up and inserting materials into the mold and to join steel edges, top edges and running surface member simultaneously with their forming. Moreover, it is always possible to provide high-quality skis (uniform in quality) because edges are fixed by plates of metal and prevented from being moved under the cycle of molding operation, thereby to permit them to be embedded and secured in place.

What is claimed is:

1. A fiber reinforced plastic ski comprised of:

an integral, laminated base of fiber-reinforced plastic material, which extends the length of said ski; said base having integral side members extending upward to contact an upper plate; said base also having a lower running surface member, which extends the length of said ski and is laminated beneath said base; said running surface member having a lower surface beneath said ski;

a laminated substantially flattened upper plate of fiber reinforced plastic material, which extends the length of said ski and meets said side members; with said base and its said side members, said upper plate defines an interior cavity within said ski; said upper plate having an upper surface above said ski, and having edges along said upper surface;

at least one reinforcing rib, integrally formed as part of said base, extending upward from said base and into contact with said upper plate, which is substantially the same height as said side members and is disposed within said interior cavity;

along the length of said base running next to both sides of said running surface member, each side of said base is cut out for receiving a respective lower edge member;

. two lower edge members, each extending the length of said ski, and extending down to be even with said ski running surface, being received within the said respective base cut out therefor; each said lower edge member including a surface which faces said lower surface of said ski; each said lower edge member also defining a lower edge for said ski; each said lower edge member including a portion, displaced away from said ski lower surface, which extends toward the other said lower edge member;

retaining means for said lower edge members; said retaining means being laminated into said laminated base for being securely held in position; said lower edge member retaining means including vertically offset pawl elements, which respectively either engage one of said edge members from above or engage it from below by engaging the said displaced portion thereof;

said upper plate having a respective upper edge member embedded in its said upper surface along both said upper edges and extending the length of said ski.

2. A fiber reinforced plastic ski of claim 1, wherein said retaining means comprises at least one plate extending across said ski and being disposed within said base, whereby said retaining means retains both said lower edge members; said retaining means being cut inward from its edges to define the individual said pawl elements, which are upraised or lowered to be positioned, respectively, above or below said lower edge members.

3. A fiber reinforced plastic ski of claim 1, wherein along the length of said upper plate near its said upper surface, said plate is cut out for receiving said upper edge members; said upper edge members being received within the respective said cut outs therefor; said upper edge members each including a surface which faces said upper surface of said upper plate; each said upper edge member also defining a respective upper edge of said ski; each said upper edge member including a portion displaced from said upper surface of said upper plate, which displaced portion extends toward the other said upper edge member;

retaining means for said upper edge members; said retaining means being laminated into said upper plate for being securely held in position; said upper edge member retaining means also including vertically offset pawl elements, which respectively either engage at least one of said upper edge members from below or engage it from above by engaging the said displaced portion thereof.

4. A fiber reinforced plastic ski of claim 3, wherein each said retaining means for each of said upper and said lower edge members comprises a respective at least one plate extending across said ski and being respectively disposed within said upper plate and said base, whereby each said retaining means plate retains, respectively, both of said upper edge members and both of said lower edge members; each said retaining means being cut inward from its edges to define the individual said pawl elements, which are upraised or lowered

Claims

1. A fiber reinforced plastic ski comprised of: an integral, laminated base of fiber-reinforced plastic material, which extends the length of said ski; said base having integral side members extending upward to contact an upper plate; said base also having a lower running surface member, which extends the length of said ski and is laminated beneath said base; said running surface member having a lower surface beneath said ski; a laminated substantially flattened upper plate of fiber reinforced plastic material, which extends the length of said ski and meets said side members; with said base and its said side members, said upper plate defines an interior cavity within said ski; said upper plate having an upper surface above said ski, and having edges along said upper surface; at least one reinforcing rib, integrally formed as part of said base, extending upward from said base and into contact with said upper plate, which is substantially the same height as said side members and is disposed within said interior cavity; along the length of said base running next to both sides of said running surface member, each side of said base is cut out for receiving a respective lower edge member; two lower edge members, each extending the length of said ski, and extending down to be even with said ski running surface, being received within the said respective base cut out therefor; each said lower edge member including a surface which faces said lower surface of said ski; each said lower edge member also defining a lower edge for said ski; each said lower edge member including a portion, displaced away from said ski lower surface, which extends toward the other said lower edge member; retaining means for said lower edge members; said retaining means being laminated into said laminated base for being securely held in position; said lower edge member retaining means including vertically offset pawl elements, which respectively either engage one of said edge members from above or engage it from below by engaging the said displaced portion thereof; said upper plate having a respective upper edge member embedded in its said upper surface along both said upper edges and extending the length of said ski.

3. A fiber reinforced plastic ski of claim 1, wherein along the length of said upper plate near its said upper surface, said plate is cut out for receiving said upper edge members; said upper edge members being received within the respective said cut outs therefor; said upper edge members each including a surface which faces said upper surface of said upper plate; each said upper edge member also defining a respective upper edge of said ski; each said upper edge member including a portion displaceD from said upper surface of said upper plate, which displaced portion extends toward the other said upper edge member; retaining means for said upper edge members; said retaining means being laminated into said upper plate for being securely held in position; said upper edge member retaining means also including vertically offset pawl elements, which respectively either engage at least one of said upper edge members from below or engage it from above by engaging the said displaced portion thereof.

4. A fiber reinforced plastic ski of claim 3, wherein each said retaining means for each of said upper and said lower edge members comprises a respective at least one plate extending across said ski and being respectively disposed within said upper plate and said base, whereby each said retaining means plate retains, respectively, both of said upper edge members and both of said lower edge members; each said retaining means being cut inward from its edges to define the individual said pawl elements, which are upraised or lowered to be positioned, respectively, above or below the respective said edge members.

5. A fiber-reinforced plastic ski as claimed in claim 1, in which a plurality of reinforcing ribs are provided.

6. A fiber-reinforced plastic ski as claimed in claim 1, in which said reinforcing rib is in the shape of a zigzag which extends lengthwise along said ski.