US3628789A

US3628789A - Ultrasonic object-supporting system in a ski-slope or the like

Info

Publication number: US3628789A
Application number: US804451A
Authority: US
Inventors: Leonard W Suroff
Original assignee: Ultrasonic Systems Inc
Current assignee: Ultrasonic Systems Inc
Priority date: 1969-03-05
Filing date: 1969-03-05
Publication date: 1971-12-21
Anticipated expiration: 1988-12-21

Abstract

An object-supporting system in the form of a ski support surface adapted to transmit ultrasonic mechanical vibrations so as to quantitatively reduce the frictional sliding engagement between the skis of the skier and the ski support surface.

Description

United States Patent Leonard W. Surolf Jericho, N.Y.

Mar. 5, 1969 Dec. 21, 1971 Ultrasonic Systems, Inc. Fnrmtngdale, N.Y.

lnventor Appl. No. Filed Patented Assignee ULTRASONIC OBJECT-SUPPORTING SYSTEM IN A SKI-SLOPE OR THE LIKE 11 Claims, 3 Drawing Fi l.

US. Cl. ..272/56.5 SS, 198/220 DC, 104/58 Int. Cl. A63g 21/14 Field of Search 198/220 B,

220 D, 220; 221/167, 268; 273/86; 272/565 R, 56.5 SS; 310/26, 28; 35/19 A; 104/58; 222/199, 409

References Cited UNITED STATES PATENTS 7/1939 Gueydan 5/1946 Plebanek... 12/1950 Devol 4/1957 Hopkins 2/1966 Maury 12/1963 Kleesattel et al.

FOREIGN PATENTS 8/1957 GreatBritain 8ll927 Germany Primary Examiner-Anton O. Oechsle Assistant Examiner-Arnold W. Kramer 273/86 X 198/220 X 198/220 198/220 X 273/86 X 226/196 X ABSTRACT: An object-supporting system in the form of a ski support surface adapted to transmit ultrasonic mechanical vibrations so as to quantitatively reduce the frictional sliding engagement between the skis of the skier and the ski support surface.

PATENTEH 0582] an SHEET 1 [IF 2 PATENTEB M021 l9?! SHEET 2 OF 2 INVENTOR LEONARD W. SUROFF ULTRASONIC OBJECT-SUPPORTING SYSTEM IN A SKI- SLOI'E OR THE LIKE BACKGROUND OF THE INVENTION This invention relates to an obj cot-supporting system to provide a minimum of frictional interference and more particularly is concerned with the method and apparatus for providing a ski-slope having an ultrasonically vibrated surface for substantially reducing the frictional sliding engagement between the skis and ski-slope.

The present invention is applicable to the use of a substantially planar surface having an object moving thereacross, which speed of movement is related to the degree of friction between the object and surface, and which frictional resistance is reduced by ultrasonically vibrating the surface. The object-supporting system is applicable to a skating rink, skislope, toboggan run, rail cars, etc., and since this invention is ideally suited for use with a ski-slope it will be so illustrated and described.

Common to all prior art devices with respect to an artificial ski surface, is an attempt to reduce the coefficient of friction between the ski surface and the skis of the skier to pennit movement down the slope as if it was covered with snow. Aside from artificial snow, the use of plastic materials in sections having various shapes and configurations have been proposed but all are rather expensive in initial cost as well as installation cost. The plastic artificial ski surface has the further drawback that once a texture is selected for a certain degree of frictional interference then it cannot be conveniently altered once applied to the slope.

OBJECT OF THE INVENTION It is therefor an object of the invention to provide an improved method and apparatus for producing a surface adapted to be ultrasonically vibrated to obtain substantial friction reduction between any object crossing it and the support surface.

Another object of the invention is to provide an artificial ski-slope having a metallic, or other energy transmitting material, vibrated at an ultrasonic rate with a small amplitude of vibration in the direction perpendicular to the ski support surface so that the vibrations quantitatively reduce the frictional resistance to the skis.

Another object of the invention is to provide an artificial ski-slope in which the coefficient of friction between ski support surface and skis may be varied depending on the desire of the skier or weather.

Other objects and advantages of the invention will be apparent as the disclosure proceeds.

SUMMARY OF THE INVENTION The method and apparatus of the invention is obtained by providing an object-supporting surface adapted to be vibrated at an ultrasonic rate, with the term ultrasonic defined to include vibrations in the range of 10,000 to 1,000,000 cycles per second, on which the object is adapted to move.

The present invention pennits an individual to ski down a slope with skis on without the necessity of having snow or some other artificial medium thereon. This immediately permits an individual in warm weather to utilize ski-slopes that have heretofore had to rely on manmade or natural snow. By providing a ski support surface that is ultrasonically vibrated the degree of friction reduction can be controlled by varying the amplitude and/or frequency of vibration.

Accordingly, when the object-supporting system is in the form of an ultrasonic skislope one or more sheets or webs form the ski support surface which are subjected to static pressure supplied by the skis of the skier, while the ski support surface is vibrated at least in a plane perpendicular to the static pressure so that relative movement or displacement between skier and ski-slope is effected in the direction of the slope. The

' antifriction effect of the vibrations of the ski support surface being relied upon to permit the free movement of the skis relative to the ski support surface in the direction of the slope.

In accordance with the present invention and ski support surface is utilized having a plurality of zones of vibratory motion with at least each pair of zones in the direction of the slope spaced not further than the length of a ski such that the skier is always suspended on at least two zones of vibratory motion. By being able to control the amplitude and frequency of vibration, by control means, it is possible to properly monitor same such that depending upon the degree of competence of the individual he might, if he so desires for his ski run, preselect the degree of friction reduction that suits his needs. For example, the slope can be made as fast as if it were pure ice or were essentially earth such that between the two the degree of friction may be selected.

Since the ski support surface need include at least portions thereof capable of transmitting ultrasonic vibrations it may be composed of both web portions of plastic and transversely extending vibratory elements of substantial length in the direction transverse to the slope while the sheets or webs are positioned therebetween. If the ski surface is made of separate members then they may vibrate simultaneously at a number of locations along the ski support surface by coupling one or more transducers thereto, thereby ensuring that a plurality of zones or points along the desired ski support surface will have elastic vibratory energy introduced therein so that each ski always is in contact with substantially two vibratory zones.

In accordance with an aspect of the present invention, the ski support surface is supported so that the ultrasonic energy may be applied thereto and have a component of vibration at the surface, and the vibratory energy of the present invention may be so directed as to simultaneously provide components of motion both in the shear mode and perpendicular to the surface. The two-directional motion may result from generating an orbital vibration at the contact edge of the vibratory element or by providing an element having its contact surface vibrating in a plane at an angle less than to the plane of the ski support surface.

In accordance with another aspect of the invention, the vibrations are applied to the member forming the support surface, and the high frequency and amplitude of the vibrations are selected so as to achieve large peak accelerations, for example, accelerations of the order of at least 1,000 G. G" being the symbol representing gravitational acceleration, whereby a relatively small static force in the direction of the slope by the skier produces relatively large dynamic forces between theskis and ski support surface to effect the desired relative movement therebetween.

In accordance with another aspect of the invention the ski support surface is comprised of a plurality of support members in transversely spaced apart relationship a given distance apart, which distance is generally less than the distance of the length of the skis, in this manner the remaining portion of the support surface might be at the same level or below that of the vibratory surface of the support members such that one essentially skims along the ski support surfaces merely touching upon the edges or tops of the support members which are vibrating.

BRIEF DESCRIPTION OF THE DRAWINGS Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself, and the manner in which it may be made and used, may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part hereof, wherein like reference numerals refer to like parts throughout the several views and in which:

FIG. 1 is a diagrammatic view in perspective of an ultrasonic object-supporting system in the form of a ski-slope according to the present invention;

FIG. 2 is a greatly enlarged end view illustrating the motion of the vibratory surface and skis shown in FIG. 1, to aid in explaining the reduction of friction concept; and

FIG. 3 is a diagrammatic view which illustrates an alternate form of ultrasonic objectsupporting system in the form of a ski-slope in accordance with the invention.

PREFERRED EMBODIIMENTS OF THE INVENTION Referring to the drawings in detail and initially to FIGS. 1 and 2 thereof, it will be seen that an object-supporting system in the fonn of an ultrasonic ski-slope embodying the present invention is generally identified by the reference numeral 10, and includes supporting means 12 having a ski support surface means 14 which is ultrasonically vibrated and on which the skier 15 can ski with skis l6 contacting the ski support surface 14 which is sloped downwardly at any desired angle as well as curvature. The ski support surface 14 may be formed from one or a plurality of individual support members 18 in the fonn of sheets or panels extending from several feet to several thousand feet in length and having a width which is convenient to transport, as for example, 4 to 50 feet in width. The support member 18 is formed out of material capable of transmitting ultrasonic vibrations, which is preferably metallic, plastic or some composite or laminate material. The support member is relatively thin as compared to its width or length and defines a planar ski support surface 14 which may be of a thickness in the range of 0.0I0-0.l0 inches. The support members 18 may be supported on the ground or by vertically extending support beams 20 used in spaced apart relation to each other as part of the supporting means 12.

To produce the friction reduction efiect ultrasonic vibration generating means 22 is utilized and is coupled to the support surface 14 so as to apply ultrasonic energy to the support surface to produce mechanical vibrations having a component substantially normal to the support surface 14 so that the coefficient of friction between the ski support surface 14 and skis I6 is substantially reduced to permit skiing thereon. The vibration may be continuous to vibrate the entire ski support surface in phase, or due to the size of the surface zones of vibratory motion 25 may be produced either in a predetermined spacing or by random vibration. Accordingly the generator means 26 may be of the type adapted to continuously vary the frequency of vibration of the transducer or ul trasonic motor 28 so as to vary the position of the zones 25 of vibration therealong so as to prevent substantial heat buildup along the surface means 14 at any location thereon.

Accordingly, the vibration generating means 22 includes a vibration generator 26, which may be of an adjustable type to vary frequency by control knob 29 and power to vary amplitude by control knob 30, and one or more ultrasonic motors or transducers 28 coupled to the underside surface 32 of the support members 18 so as to generate ultrasonic mechanical vibrations, and connected by cables 34 to the generator 26. The transducer 28 may be one of a number of electromechanical types, such as, electrodynamic, piezoelectric or magnetostrictive, however, for the operating range of frequencies most desirable for an ultrasonic ski-slope, the transducer 28 is preferably of the magnetostrictive type. The magnetostrictive transducer 28 is preferably formed of a metal, such as, permanicklc, nickel, permendur, or other metals which have high tensile strength and are highly magnetostrictive in character, so that the transducer will vibrate to a maximum degree when subjected to the influence of a biased alternating electromagnetic field established by biased alternating current supplied to a surrounding driving coil or winding from the oscillation generator 26. The transducers 28 produce ultrasonic vibration which effects elastic vibration of the ski support surface 14 at a high frequency of at least 10,000 cycles per second with peak accelerations of the order of at least 1,000 G, whereby the frictional resistance to the skis 16 is quantitatively reduced so that the force to permit skiing may be of a relatively small magnitude.

By coupling one or more transducers 28 to the bottom 32 of the ski support surface 14 the plurality of zones 25 of vibratory motion may be obtained in the direction of motion of the object in the form of skis 16, with the spacing of the zones 25 being such that each ski I6 is substantially always in supporting relationship to at least two zones of vibratory motion. It is possible to vibrate the entire support surface 14 in a certain phase relationship, but to be economical with respect to the power required it is deemed desirable that as long as there are sufficient number of zones of motion, having a component in the plane normal to the direction of movement the skier 15, that the friction reduction effect will be sufficient to permit him to propel himself downward at a rapid speed on a metallic or other surface.

The actual length of the slope may be from several feet to several thousand feet, and extend on a hillside or as indicated formed uprightly on support beams 20. In any event the magnitude of friction reduction is in part related to the actual amplitude of vibration as seen in FIG. 2, in that the ski support surface 14 is moving from between the solid line, at the end of a vibratory cycle, to the phantom surface line at the other end of the vibratory cycle, approximately 20,000 cycles per second, at say an amplitude of vibration of 0.002 inch, which essentially means that it is continuously falling away from the bottom surface 36 of the ski 16 at a quicker rate than the gravitational force of gravity such that in a sense only upon the supporting surface 14 reaching its peak height is it momentarily in contact with the bottom surface 36 of the skis. This phenomenon is a unique property of ultrasonic vibratory mechanical energy which can be utilized in a ski-slope so as to permit one to ski down with a minimum of resistance. Controlling the coefticient of friction between the object in the form of skis l6 and ski-slope 10 is obtained by varying the amplitude and/or frequency of vibration which makes it possible to control the degree of friction reduction, which is controllable by the individual or operator of the slope. This control is obtainable by adjusting the knob 29 and or knob 30.

It has been found that, by reason of the vibrations in a plane perpendicular to the direction of the static force, the frictional resistance of the skis 16 to movement on the ski-slope I0 is vary substantially reduced. A possible explanation of this observed phenomenon is that the extremely high acceleration of the upper surface of the ski support surface 14 resulting from the vibrations causes only a relatively small sliding friction to be present between the engaged ski I6 and the surface 14. Thus, even though the ski support surface 14 is stationary and may have a flat surface, the skis 16 are nevertheless easily displaceable with respect thereto, for example, in the direction of the slope on FIG. 1, thereby to easily move down the slope.

The static pressure or force exerted on the ski support surface 14 may be in the range of between approximately 50 to 5,000 pounds in a given area, such as by one or more skiers or a snowmobile or toboggan. As illustrated in FIG. 2, the frequency of the vibrations between the solid and phantom line at a zone 25 at the free end portion of the ski support surface 14 may be in the range from 10 to I00 kilocycles per second and preferably in the range from 10 to kilocycles per second, while the amplitude of the vibrations is selected within the range from approximately 0.0005 to 0.025 inch so as to ensure the introduction of vibratory energy sufficient to substantially minimize the frictional resistance of the support surface 14 to the advancement of the skis 16. It is appreciated that one or more skiers 15 may simultaneously use the skislope 10.

So as to be able to automatically turn off the power required when the skier 15 has fallen, detecting means 40 is provided at one or more locations along the ski-slope 10 and may include an upper and lower

electric eye beam

42 and 44, respectively, conventionally mounted with respect to the ski-slope 10 with control means 45 coupled thereto such that if a skier were to fall down and only the bottom beam were closed when he passed through it, the circuit, will automatically shut off the generator 26 and the vibratory energy cease. But as long as he passed upright through beams 42 and M simultaneously the power generating means 22 would continue to operate.

FIG. 3 illustrates another embodiment of an object-supporting system 10a of the present invention wherein the skiing is obtained by the individual on supporting means 12a in the form of a ski support surface 140 that is capable of transmitting ultrasonic vibrations which are produced having a component of motion substantially normal to the ski support surface 140 so that the coefficient of friction between the ski support surface 14a and skis 16d of the skier a is substantially reduced to permit skiing thereon. The ski support surface 140 may be comprised of a plurality of support or vibratory members 184 extending transversely across the slope l0 and may be supported on a total assembly as seen in FIG. 1, or may be embedded beneath the ground 470 such that the upper edges 504 are vibrated to produce the zones of motion 250 that extend above the support spacers 52a and housed in a casing 540 extending within the ground. The mounting frame 550 from the support member 180 may be of the type in accordance with US. Pat. No. 3,113,225, which illustrates the construction of this type of bladelike transmission member capable of use in accordance with the present invention. The ultrasonic motor 280 is coupled to the rear of the support member 180.

Extending between the respective support members 18a may be sheets of support spacers 52a of material that might be in the same plane with or slightly below the plane with the upper edge 500 such that essentially the skis l6aare always supported by at least two zones of motion 25a on the ski support surface 14a. The support members 180 have their upper edge constituting the zones of vibratory motion 250 which may be similarly adjusted as to both amplitude of vibration and frequency as previously explained. In this embodiment if used for a narrower object as a toboggan sled then the support members may be placed in end to end relationship to form a single rail or a pair of rails as railroad tracks.

Although illustrative embodiments of the invention have been described in detail herein with reference to the accompanying drawing, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention.

1 claimi l. The method for obtaining an artificial ski-slope comprising the steps of A. providing a substantially continuous, planar, relatively thin ski-supporting surface capable of transmitting ultrasonic vibrations and capable .of supporting a skier wearing skis thereon,

B. maintaining said ski-supporting surface in an inclined position such that one end thereof is at a higher elevation than the opposite lower end so that a skier may ski down the resultant slope by gravity from said higher end to said lower end,

C. coupling a plurality of spaced apart electromechanical vibratory mechanism means to the bottom side of said ski-supporting surface for transmitting mechanical vibrations in spaced apart zones on said ski-supporting surface, and

D. activating said electromechanical vibratory mechanism means to produce said vibration zones at high frequency and low amplitude having a component substantially normal to said ski-supporting surface, and with peak acceleration's of the order of at least 1,000 G, whereby the coefficient of friction between said ski-supporting surface and the skis of the skier is quantitatively reduced.

2. The method as defined in claim 1, wherein said zones of vibratory motion are coupled to said surface at distances selected relative to the size of the skis to be supported thereon.

3. The method as defined in claim 1, wherein said electromechanical vibratory mechanism means are coupled to said surface at distances wherein the spacing between said zones of vibratory motion is such that each ski is substantially always in supporting relationship with at least two zones of vibratory motion.

4. A method as defined in claim 1, wherein said mechanical vibrations are at a frequency of at least 10,000 cycles per second.

5. A method as defined in claim I, and further including the step of controlling the coefficient of friction between the skis and ski-slope by varying the amplitude of vibrations of said surface.

6. A method as defined in claim 1, and further including the step of detecting when a skier has fallen on said ski-slope and discontinuing the vibration of said surface.

7. An artificial ski-slope comprising A. a substantially continuous, planar, relatively thin ski-supporting surface capable of transmitting ultrasonic vibrations and capable of supporting a skier wearing skis thereon,

B. means for maintaining said ski-supporting surface in an inclined position such that one end thereof is at a higher elevation than the opposite lower end so that a skier may ski down the resultant slope by gravity from said higher end to said lower end,

C. a plurality of spaced apart electromechanical vibratory mechanism means coupled to the bottom side of said skisupporting surface for transmitting mechanical vibrations in spaced apart zones on said ski supporting surface, and

D. generator means for activating said electromechanical vibratory mechanism means,

E. said electromechanical vibratory mechanism means producing said vibration zones at high frequency and low amplitude having a component substantially normal to said ski-supporting surface, said mechanical vibrations producing peak acceleration s of the order of at least L000 G, whereby the coefficient of friction between said ski-supporting surface and the skis of the skier is quantitatively reduced.

8. The artificial ski-slope as defined in claim 7, wherein said vibration effects elastic vibration of said surface means at a frequency of at least 10,000 cycles per second.

9. The artificial ski-slope as defined in claim 7, wherein said spacing between said zones of vibratory motion is spaced longitudinally of the ski-supporting surface at a distance of less than one-half the length of the ski such that the skier is substantially always in supporting relationship to at least two zones of vibratory motion.

10. The artificial ski-slope as defined in claim 7, and further including means for varying the amplitude of vibration of said surface to control the coefficient of friction between the skis and surface.

11. The artificial ski-slope as defined in claim 7, and further including detecting means for determining when a skier has fallen on said ski-slope and discontinuing the vibration of said surface.

i I i

Claims

1. The method for obtaining an artificial ski-slope comprising the steps of A. providing a substantially continuous, planar, relatively thin ski-supporting surface capable of transmitting ultrasonic vibrations and capable of supporting a skier wearing skis thereon, B. maintaining said ski-supporting surface in an inclined position such that one end thereof is at a higher elevation than the opposite lower end so that a skier may ski down the resultant slope by gravity from said higher end to said lower end, C. coupling a plurality of spaced apart electromechanical vibratory mechanism means to the bottom side of said skisupporting surface for transmitting mechanical vibrations in spaced apart zones on said ski-supporting surface, and D. activating said electromechanical vibratory mechanism means to produce said vibration zones at high frequency and low amplitude having a component substantially normal to said skisupporting surface, and with peak acceleration''s of the order of at least 1,000 G, whereby the coefficient of friction between said ski-supporting surface and the skis of the skier is quantitatively reduced.

5. A method as defined in claim 1, and further including the step of controlling the coefficient of friction between the skis and ski-slope by varying the amplitude of vibrations of said surface.

7. An artificial ski-slope comprising A. a substantially continuous, planar, relatively thin ski-supporting surface capable of transmitting ultrasonic vibrations and capable of supporting a skier wearing skis thereon, B. means for maintaining said ski-supporting surface in an inclined position such that one end thereof is at a higher elevation than the opposite lower end so that a skier may ski down the resultant slope by gravity from said higher end to said lower end, C. a plurality of spaced apart electromechanical vibratory mechanism means coupled to the bottom side of said ski-supporting surface for transmitting mechanical vibrations in spaced apart zones on said ski-supporting surface, and D. generator means for activating said electromechanical vibratory mechanism means, E. said electromechanical vibratory mechanism means producing said vibration zones at high frequency and low amplitude having a component substantially normal to said ski-supporting surface, said mechanical vibrations'' producing peak acceleration''s of the order of at least 1,000 G, whereby the coefficient of friction between said ski-supporting surface and the skis of the skier is quantitatively reduced.