US3350092A

US3350092A - Structural elements for an artificial ski slide

Info

Publication number: US3350092A
Application number: US418060A
Authority: US
Inventors: Maki Isao
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-12-14
Filing date: 1964-12-14
Publication date: 1967-10-31
Anticipated expiration: 1984-10-31

Description

C- 31 1967 :SAO MAKI 3,350,092

STRUCTURAL ELEMENTS FOR AN ARTIFICIAL SKI SLIDE O MAb 43 Oct. 31, 1967 |SAO MAK| 3,350,092

STRUCTURAL ELEMENTS FOR AN ARTIFICIAL SKI SLIDE Filed DSC. 14, 1964 2 Sheets-Sheen 2 United States Patent C 3,350,092 STRUCTURAL ELEMENTS FOR AN ARTIFICIAL SKI SLIDE Isao Maki, 85 Z-chome, Nihonbashihama-cho, Chun-ku, Tokyo, Japan Filed Dec. 14, 1964, Ser. No. 418,060 5 Claims. (Cl. 272-565) ABSTRACT F THE DISCLSURE This invention relates to an artificial slide for 'skiing made of a base sheet having thereon a plurality of relatively flexible needle-like projections made of thermoplastic resinous material and molded into a unitary structure, the plurality of the needle-like projections being in at least two groups, the projections of which are somewhat different in height and disposed alternately.

-man The object of the present invention is to provide an improved artificial slide for skiing, in which the sliding effect can be controlled by -tilting the ski and sliding it in a longitudinal, lateral or oblique direction.

It is another object of the present invention to provide an improved artificial slide for skiing, in which any undue slippage of the skiers ski can be prevented. Y

These and other objects of the present invention will become apparent from the following detailed description taken in conjunction with the Iaccompanying drawings wherein:

FIG. 1 is a perspective view of one structural element constructed in accordance with the teachings of the invention with parts omitted;

FIG. 2 is a fragmental view, in vertical section, of the element illustrated in FIG. l;

FIG. 3 is a top plan view of the element illustrated in FIGS. l and 2;

FIG. 4 is a bottom view of the element illustrated in FIGS. 1 through 3;

FIG. 5 is -a vertical section, showing the manner in which the structural element is deformed when the associated ski is effecting a schuss;

FIG. 6 is a vertical section, showing the manner in which the structural element is deformed upon braking a ski; and

FIGS. 7, 8 and 9 are fragmentary views of modifications ofthe invention.

Referring now to FIGS. 1 through 4 of the drawings, a structural element constructed in accordance with the teachings of the invention includes a base sheet 10, for example, in the form `of a square having a lower, relatively smooth bottom face and an upper face having a plurality of ribs formed integrally thereon in a grid arrangement as best shown in FIG. 3. The ribs 20 serve to prevent the base sheet 10 from warping and also serve to prevent any undue slip of the lower end of the skiers stock. It is to be understood that the base sheet may, if desired, have any suitable shape other than the square shape as long as a plurality of the base sheets can continuously cover an area of a plane and that the ribs may be disposed in -any other suitable arrangement as long as they serve to prevent warping of the base sheet. For example, instead of the square shape the base sheet may have, for example, a rectangular, rhombic or trapezoidal shape, or an equilateral triangle, an isosceles triangle, or a regular hexagon or the like. The element 10 further includes a needle unit generally designated by the reference numeral consisting of a multiplicity of relatively highly flexible needle-like projections extending upwardly from and substantially at right angles` to the plane of the upper face of the base sheet 10.

3,350,092 Patented Oct. 31, 1967 As shown in FIGS. l and 2, the needle unit 30 includes longer and shorter needle-

like projections

31 and 32, respectively, disposed alternately as viewed in longitudinal, transverse and oblique directions, as shown in FIGS. 1 and 2.

According to the teachings of the invention, the structural element as above' described is composed of any suitable thermoplastic resinous material having a relatively high flexibility or pliability and molded into a unitary structure. The preferred materials for the element are polypropylenes and polyethylenes. The use of the molding technique is possible so that mass production can be used resulting in cheap elements. Also the use of the thermoplastic resinous materials leads to an advantage that the elements can be effectively washed with water and/ or any suitable chemical for cleaning purpose. Further the present elements are advantageous in that, even if any excessive force would be externally applied to the elements, the same are not damaged due to their flexibility and that they do not injure persons and articles.

Said plurality of needle-like projections are divided into two groups, one group comprising the needle-like projections 31 of larger height land the other group comprising the needle-like projections 32 of smaller height, and said larger and smaller needle-like projections are arranged alternately in all longitudinal, transverse and oblique directions of the rows, as shown in FIG. 3.

Preferably the needle-

like projections

31 and 32 each have an enlarged root portion integrally connected to the upper face of the base sheet 10 and are tapered toward the free extremity with the latter somewhat round. With the needle-like projections shaped in the manner just described, the material for the element is permitted to easily flow into a mold during the injection molding operation.

The needle-

like projections

31 and 32 should he disposed on the base sheet 10 close enough to prevent the front end portion of a skiers stock moving on the elements to tend to forcedly project between any pair of the adjacent projections. In other words, the spacing between two adjacent needle-like projections should be narrower than the diameter of the front end portion of the stock. This measure ensures the moving skiers stock against the danger that the stock slides directly along the upper faces of the aligned base sheets 10' due to a forced entrance of the stock extremity between the two adjacent needle-like projections.

In order for the structural elements 10` as above described to be rigidly secured on a natural or artificial inclined foundation, the base sheet 10 is provided with marginal portions on the entire length of the sides thereof. More specifically, as clearly shown in FIGS. 2 through 4, the square base sheet 10 includes an Lashaped flange or marginal portion 41 projecting outwardly from the two adjacent sides and another L-shaped flange or marginal portion 42 projecting outwardly from the remaining sides with the marginal portions perforated at 43. The marginal portion 41 has its lower surface forming an extension of the lower face of the base sheet 10 and the marginal portion 42 has its upper surface forming an extension of the-upper face of the sheet. The lower and upper surfaces respectively of the

marginal portions

41 and 42 are designed and constructed such that, when the marginal portion 42 of one element 10 is superposed on the marginal portion 41 of the adjacent element, the upper and lower surfaces of the superposed

marginal portion

42 and 41 are flush with the upper and lower faces of the base sheets 10 respectively. To this end, the unarginal portions are preferably a half the thickness of the base sheet.

It will be appreciated that, with the element aligned in the manner just described, the perforations 43 on the marginal portion of one clement are registered with the associated perforations 43 on the superposed marginal portion of the adjacent element.

In order to construct an artificial Gelande, a number of the structural elements as above described are placed on a foundation such as shown at the reference character D in FIGS. 2 or 5, in such a manner that the marginal portion 42 of one element is superposed on the marginal portion 41 lower in level than the adjacent element, and then maybe rigidly secured on the foundation D by having nails N or clamps threaded through the registered perforations 43 and fastened to the foundation D. To rigidly secure the elements 10-30 on the foundation D, any suitable bonding agent (not shown) may be injected into the `registered perforations 43 until the same reaches the foundation D. Alternatively, any suitable bonding agent may be applied to either the lower surfaces of the

marginal portions

41 and 42 or the upper surface of the foundation D. If desired, any desired combination of the processes just described may be utilized.

The

marginal portions

41 and 42 superposed in the manner as above described are advantageous in that the nails or clamps, if used, are fewer in number as compared with the case in which the marginal portions abut against each other without being superposed and that any excessive force which might be externally applied to the element will effect separation of the element from the foundation only with difficulty as compared with the case where the elements are independently mounted on the foundation.

Referring now to FIG. 5 of the drawings, there is illustrated a manner in which a ski is straight sliding along the artificial Gelande composed of the elements of the invention. As shown in FIG. 5, a ski or Sledge S has its bottom surface substantially parallel to the base sheets and brought in contact with the free extremities of the longer needle-like projections 31 which, in turn, are somewhat curved. However, the bottom surface of the ski S is not put in contact with the shorter needle-like projections 32. Under these circumstances, a skier can effect straight sliding movement on the artificial Gelande with a relatively low frictional resistance resulting in an increase in straight sliding velocity.

FIG. 6 illustrates a ski S extending substantially perpendicularly to the plane of the figure and tilted laterally. As shown, the bottom surface of the ski S is brought in contact with not only the longer needle-like projections 31 but also the shorter projections 32 resulting in an increase in frictional resistance. Therefore, the ski S is subject to a high braking force.

If the shorter needle-like projections 32 are made thinner than the longer needle-like projections 31, the element increases its exibility or pliability. Under these circumstances, if a skier desires to change from straight sliding movement to braking movement, he can very smoothly brake as he would do on a natural snow layer but would not be subject to an abruptly increased resistance leading to his falling forwardly.

Referring now to FIG. 7 wherein the same reference numerals designate similar components to those illustrated in FIGS. 1 through 4, there is illustarted a modification of the invention. The modification illustrated includes a base sheet 10` identical to that previously described in conjunction with FIGS. 1 through 4 and a needle unit 30 consisting of a multiplicity of needle-like projections similar to those already described for FIGS. 1 through 4 excepting that the needle-like projections each have on the free end portion a at rough surface 33. Due to a high frictional resistance between the rough end surfaces 33 of the needle-like projections and a bottom surface of a ski moving thereon, a skier is prevented from sliding down at a high speed along the Gelande composed of such elements. Thus the elements illustrated in FIG. 7 can Compose a Gelande suitable for be ginners.

FIG. 8 illustrates an arrangement similar to FIG. 7 excepting that each of needle-like porjections is provided on the upper end portion with a recess or well 34 in place of the upper rough end surface 33 shown in FIG. 7. The well 34 serves to increase the fiexibility or pliability of that portion of the needle-like projection surrounding the well and also exhibits a cushion effect due to the air confined by the well. This cushion effect serves to decrease the frictional resistance between the upper ends of the needle-like projections and a ski moving thereon thereby to increase the sliding speed of the ski.

In FIG. 9 there is illustarted another modification of the structural element according to the teachings of the invention wherein the needle-like projections are of a hollow type. As shown, each of needle-like projections includes a wall 35 and an axial hollow space 36 confined by the wall, closed at the upper end and opening on the bottom face of a base sheet 10'. By providing the hollow space 36, the needle-like projection can increase its flexibility and also its wall 35 can be made uniformly thin regardless of the outside diameter of the projection. In addition, the material for the structural element can not only be greatly saved but also the cushion effect can be enhanced due to the air confined by the hollow portion 36 having its lower end closed by the associated portion of a foundation D.

What I claim is:

1. A structural element for use in constructing an artificial slide for skiing, comprising a base sheet having projecting from one face thereof a plurality of exible needle-like projections and having peripheral margins therearound which are free of needle-like projections, said margins being for connecting the element with an adjacent element, said base sheet and said plurality of needlelike projections being thermoplastic resinous material, and said plurality of needle-like projections being in at least two groups, the needle-like projections of one group having a greater height than the projections in the other group, and individual needle-like projections of each group being positioned alternately with the individual needles of the other group, the needle-like projections being in rows extending in longitudinal, transverse and oblique directions on the said one face of said base sheet.

2. A structural element as claimed in claim 1, wherein each of said needle-like projections has a rough surface on the upper free end thereof.

3. A structural element as claimed in claim 1, wherein each of said needle-like projections has a recess in the upper free end thereof.

4. A structural element as claimed in claim 1, wherein each of said needle-like projections has a longitudinal hollow portion closed at the upper end and opening at the lower end out of the lower face of said base sheet.

5. A structural element as claimed in claim 1 wherein said base sheet has on said one face from which said multiplicity of needle-like projections extend a plurality of ribs composed of the same thermoplastic resinous material and formed integrally on said one face thereof and from which ribs at least some ofthe needle-like projections of said plurality of needle-like projections extend.

References Cited UNITED sTATEs PATENTS 2,174,716 10/1939 Betheu 272-565 3,047,291 7/1962 Hau 272-565 3,078,490 2/1963 Etcher 15-216 3,224,763 12/1965 Han 272-565 3,233,893 2/1966 Meyer 272-565 RICHARD C. PINKHAM, Prima/'y Examiner.

ANTON O. OECHSLE, Examiner.

A. W. KRAMER, Assistant Examiner.

Claims

1. A STRUCTURAL ELEMENT FOR USE IN CONSTRUCTING AN ARTIFICIAL SLIDE FOR SKIING, COMPRISING A BASE SHEET HAVING PROJECTING FROM ONE FACE THEREOF A PLURALITY OF FLEXIBLE NEEDLE-LIKE PROJECTIONS AND HAVING PERIPHERAL MARGINS THEREAROUND WHICH ARE FREE OF NEEDLE-LIKE PROJECTIONS, SAID MARGINS BEING FOR CONNECTING THE ELEMENT WITH AN ADJACENT ELEMENT, SAID BASE SHEET AND SAID PLURALITY OF NEEDLELIKE PROJECTIONS BEING THERMOPLASTIC RESINOUS MATERIAL, AND SAID PLURALITY OF NEEDLE-LIKE PROJECTIONS BEING IN AT LEAST TWO GROUPS, THE NEEDLE-LIKE PROJECTIONS OF ONE GROUP HAVING A GREATER HEIGHT THAN THE PROJECTIONS IN THE OTHER GROUP, AND INDIVIDUAL NEEDLE-LIKE PROJECTIONS OF EACH GROUP BEING POSITIONED ALTERNATELY WITH THE INDIVIDUAL