US3503621A

US3503621A - Fiber glass ski with channel construction

Info

Publication number: US3503621A
Application number: US727569A
Authority: US
Inventors: Klaus D Schmidt; Merritt A Robinson
Original assignee: Kimball-Schmidt Inc
Current assignee: Kimball-Schmidt Inc
Priority date: 1968-05-08
Filing date: 1968-05-08
Publication date: 1970-03-31
Anticipated expiration: 1987-03-31

Description

March 31, 1970 K, @SCHMIDT m1 3,503,621

FIBER GLASS SKI WITH CHANNEL CONSTRUCTION Filed May 8. 1968 FIG-3 ATTORNEYS United States Patent O 3,503,621 FIBER GLASS SKI WITH CHANNEL CONSTRUCTION Klaus D. Schmidt, San Francisco, and Merritt A. Robinson, San Anselmo, Calif., assignors to Kimball-Schmidt, Inc., San Rafael, Calif., a corporation of California Filed May 8, 1968, Ser. No. 727,569 Int. Cl. A63c 5/12 U.S. CI. 280-1L13 1 Claim ABSTRACT OF THE DISCLOSURE A fiber glass ski having two lengthwise members at least one of which has a molded-in camber and a U-shaped channel construction, the ski being filled with a plastic foam material. When both members are provided with a U-shaped channel construction the members are telescoped together. Steel edges can be inserted along the length of the ski with portions of said edges being disposed between the telescoped side walls of the ski members.

BACKGROUND OF THE INVENTION At present, fiber glass skis are beginning to come into relatively wide usage. However, to the best of applicants knowledge all of such skis are made by laminating a core material and upper and lower ber glass shell members.

One of the most common problems with such skis is that of delamination. During normal use a ski must flex from tip to tail, placing the laminated interfaces of the skis in longitudinal shear. In many instances, the repeated flexing'will cause the ski to fail along the planes of lamination.

Additionally, the laminated construction presently used makes it difficult to control the degree of camber which the finished ski is to have. Even though the individual layers of the ski will be formed with a desired amount of camber in each, when all are assembled together the final camber will not always be precisely that which is desired.

Further, all snow skis are provided with steel edge members along the length thereof, such members being generally fastened by screws to the ski. These edges are subjected to high horizontal forces tending to pull them sideways from the ski and edge failures have proven troublesome.

SUMMARY OF THE INVENTION The above problems of fiber glass skis have been solved by the present invention in several ways.

First of all, instead of utilizing the usual lamination-of flat layers of fiber glass and core material, applicants form a lower ski member of a single piece of fiber glass material having a generally U-shaped construction throughout its length, so that the side walls of the lower ski member also form the side walls of the ski. The top of the ski is then enclosed by an upper member which is bonded to the side walls of the lower member, thus forming an elongated box, in which the core material is disposed.

`The shear load in the ski is then taken up by the four corner edges of the ski and the extensive contact area between the two laminates, all of which are integral with the lower ski member, thus reducing substantially the failure of the ski from normal fiexure during use.

In addition, the fact that the side walls of the ski are integral with the bottom surface enables the camber to be accurately retained after molding, since the side walls will resist the tendency of the bottom surface to flatten out after molding.

3,503,621 Patented Mar. 31, 1970 ICC The advantages above can be enhanced by molding both the upper and lower members so that they have a lengthwise channel construction. The members are telescoped together and the side walls bonded together along their length. With such construction there is no lengthwise plane of the ski in which flexure-induced shear stresses are imposed upon bonded interfaces alone.

The double channel construction has a further advantage in that it enables steel edge members to be inserted between the telescoped side walls of the ski members. The edge members are thus held from pulling away from the ski by the basic structure of the ski rather than merely by screws or other bonding means.

Other objects and advantages will become apparent in the course of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, forming a part of this application, and in which like parts are designated by like reference numerals throughout the same,

FIG. l is a side elevation of a ski embodying the principles of this invention;

FIG, 2 is a plan view of a ski as shown in FIG. 1;

FIG. 3 is a cross-sectional view of the ski of FIG. l, taken on line 3-3 thereof;

FIG. 4 is a cross-sectional view of the ski of FIG. 1, taken on line 4-4 thereof;

FIG. 5 is a cross-sectional view, similar to FIG. 4, showing another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and particularly to FIGS. 1-4 thereof, FIG. 1 illustrates a side view of the ski 10 having a tip or shovel portion 11 and a tail portion 12. As is conventional, the shovel portion curves upwardly and forwardly from point 13 and the ski is curved upwardly from point 13 to the tail to give the ski its desired and necessary camber.

The body of the ski 10 is comprised primarily of three elements: the lower ski member 14, the core 15 and upper ski member 16. As is shown in FIGS. 3 and 4, the lower ski member has a running portion 17, and

upstanding side walls

18 and 19 which run throughout the length of the ski, thus forming a generally U-shaped channel. The upper ski member 16 has an upper portion 21 and downwardly depending

side walls

22 and 23, thus forming a generally inverted U-shaped channel which runs throughout the length of the ski.

The ski is built up as follows. A mold (not shown) having the outside configuration of the lower ski member is utilized, the mold being formed to provide the proper camber for the ski, such camber being predetermined by wellknown techniques. A sole piece 24, of Teflon, polyethylene or similar material is first placed in the bottom of the mold cavity to extend the length thereof. A mat of interwoven glass fibers is then placed i in the mold cavity, such mat extending throughout the length of the mold, to form the running portion 17 and

side walls

18 and 19 of the lower ski member. A layer of fiber glass rovings 25 is then disposed in the mold cavity with the rovings running from one end to the other of the mold. A thermossetting resin, such as a polyester or an epoxy resin, is applied in a conventional manner to impregnate the fiber glas material in the mold. An inner mold member (not shown) is moved into the mold cavity and heat and pressure is applied, in a conventional manner, to the materials in the mold, with such heat and pressure being applied for a length of time suficient to set the resin and bond the sole piece 24 to the lower ski member 14.

The upper ski member 16 is formed in the same manner. A fiber glass mat is placed in the mold cavity of a mold having a cavity shape conforming to the outer shape of the upper ski member and having a camber complementary to that of the lower ski member. The ber glass mat extends the full length of the mold cavity. Next, a layer of fiber glass rovings 26 is disposed in the cavity with the rovings running the length of the mold. A thermosetting resin is applied to impregnate the liber glass material and heat and pressure is applied to set the resin.

The channel formed by the lower ski member 14 is then lled with a suitable plastic foam, such as an epoxy or polyurethane foam. Preferably this is sprayed in as a liquid and after a relatively short time it will harden into a solid core of foam material 15.

The lower ski member 14 thus formed is a one-piece member having the desired channel construction and predetermined camber molded thereinto. The side walls thereof will resist any tendency of the camber to change since they are interal with and perpendicular to the running portion of the ski member.

The foam core 15 may now be routed out to enable the solid

plastic llers

29 and 30 to be inserted in the channel of the lower ski member to achieve the desired thickness at the tip and tail of the ski. Such llers may be made of ABS, nylon, polypropylene, or the like. Preferably the filler 29 will extend from the tip 11 of the ski to about 10-12 inches thereform, and the ller 30 will extend from the tail 12 of the ski to about 8 inches therefrom. If desired, such filler coud be put into the lower ski member channel before the foam core is put thereinto.

Suitable bonding material, such as an epoxy, is applied to the outer surfaces of the

side walls

18 and 19 of the lower ski member 14 and/or to the inner surfaces of the

side walls

22 and 23 of the upper ski member 16, and the upper ski member is telescoped onto the lower ski member, as shown in FIGS. 3 and 4. A hardened edge member 311 preferably of steel, having an L-shaped configuration, is attached to the ski Iby inserting the upstanding flange portion 32 between the

side walls

19 and 23 of the

ski members

14 and 16. The edge member is bonded to the side walls by the bonding material thereon. Edge member 33 is similarly attached to the other side of the ski.

FIG. illustrates an embodiment of the invention wherein only the lower ber glass ski member 114 of ski 110 is formed with

side walls

118 and 119 integral with the portion 117 to form a U-shaped channel. The lower ski member 114 is formed with a sole piece 124 and layer of fiber glass rovings 125 in the same manner as previously described. Similarly, the plastic foam core 115 is formed in the same manner. The upper liber glass ski member 116 encloses the channel formed by the lower ski member and is bonded to the tops of the

side walls

118 and 119 by a suitable bonding agent.

Hardened edge members

131 and 133 are attached to the ski in any conventional manner.

With the foregoing ski construction, it has been found that such construction easily enables the channels to be made as thick or thin as desired, or to vary the thickness along the length of the channels so as to provide the lbest ilexibility of the ski, without varying the overall exterior dimension of the ski, to enable such skis to be best adapted to the particular use to which they will be put. This advantage is extremely diicult to achieve with any degree of precision in the standard laminated ski construction.

Due to the box construction of the channel-shaped members, the camber of the ski is locked in and is independent of any possible creep of the core material. Also, as previously pointed out, the shear stresses on the `ski will be resisted by the integral side walls of the channelshaped members so that lamination peelis eliminated. Particularly is this true with the double channel construction, since at no longitudinal plane is shear stress resisted solely yby interface laminations. Also with the double channel construction the steel edges can be securely locked into place, since they are held against outward movement by the

structural side walls

22 and 23 of the upper ski member 16.

Having thus described our invention, we claim:

1. A ski comprising: A

(a) a lower ski member formed of ber glass material impregnated with a set resin, said lower ski member having a lower running portion and upwardly extending side walls to form a generally U-shaped channel substantially throughout its length, and said lower ski member having a predetermined camber molded thereinto along its length;

(b) an upper ski member formed of -ber glass material impregnated with `a set resin, said upper ski member having an upper portion and downwardly extending side walls substantially throughout its length, said upper ski member having its side walls telescoped onto and bonded to the side walls of said lower ski member;

(c) a core of synthetic foam material lling said channel formed by said lower ski member;

(d) solid plastic ller members disposed between the upper portion of said upper ski member and running portion of said lower ski member adjacent the tip and tail of said ski.

References Cited UNITED STATES PATENTS 2,484,141 10/1949 Alex. 2,613,660 10/1952 Bear. 2,694,580 11/1954 Head. 3,208,761 9/1965 Sullivan et al.

FOREIGN PATENTS 220,991 4/1962 Austria. 1,435,153 3/1966 France.

U.S. Cl. X.R. l6l-l56, 159, 170

LEO FRIAGLIA, Primary Examiner MILTON L. SMITH, Assistant Examiner