US3537717A - Damped ski and method of making - Google Patents

Damped ski and method of making Download PDF

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Publication number
US3537717A
US3537717A US780088A US3537717DA US3537717A US 3537717 A US3537717 A US 3537717A US 780088 A US780088 A US 780088A US 3537717D A US3537717D A US 3537717DA US 3537717 A US3537717 A US 3537717A
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Prior art keywords
ski
damping
skis
strip
layer
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US780088A
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English (en)
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Donald B Caldwell
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3M Co
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Minnesota Mining and Manufacturing Co
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    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63C—SKATES; SKIS; ROLLER SKATES; DESIGN OR LAYOUT OF COURTS, RINKS OR THE LIKE
    • A63C5/00—Skis or snowboards
    • A63C5/12—Making thereof; Selection of particular materials
    • A63C5/122—Selection of particular materials for damping purposes, e.g. rubber or the like

Definitions

  • This invention relates to skis and to methods of improving the performance thereof.
  • skis having a shell or skeleton of metal and/or reinforced plastics having a shell or skeleton of metal and/or reinforced plastics, the interior core typically being filled with wood blocks, foamed plastic or other material which provides compressive strength.
  • Such skis are uniform, predictable, and have signiiicantly greater wear resistance and useful life.
  • Such skis have a somewhat different feel than wooden skis, typically displaying a greater degree of flutter, or vibration, particularly when used on steep or icy slopes, or when making sharp turns.
  • the present invention provide-s an improved ski construction in which mass-produced skis can be made to have the feel and lack the flutter characteristic of wooden skis.
  • the resultant product is one which combines the best physical attributes of both the earlier wooden Skis and the modern carefully constructed synthetic products. If desired, skis can be initially manufactured in accordance with the invention, but it is almost equally satisfactory to modify a pair of commercial skis to incorporate the features ⁇ of the invention, very little time or effort being required.
  • a surprising and unexpected feature of the modified ski construction is a noticeably enhanced maneuverability, as is particularly manifested by increased speed in slalom competition.
  • a viscoelastic layer which has a thickness of at least 0.015 inch (about 0.4 mm.), a glass transition temperature in the range of -55 C. to 85 C., and, at temperatures throughout the range of 25 C. to - ⁇ -5 C. and frequencies of 10-20 Hz., a loss tangent value of at least 0.5 (preferably at least 0.7) and a dynamic shear modulus in the range of 0.7-700 kg./cm.2.
  • the constraining layer and the viscoelastic layer are further selected so that the dynamic stretching stiffness of the former, measured in force per unit width, is significantly higher than (preferably at least 10 times as great as), the dynamic shear stiffness of the latter, measured in force per unit volume in the foregoing temperature and frequency ranges, all measurements being in c.g.s. units.
  • a commercial ski is conveniently modified with the aid of a strip of damping material formed by applying a viscoelastic layer to one face of a suitable constraining layer (e.g., thin aluminum sheet) and then adhering the viscoelastic layer to the upper surface of the ski.
  • a suitable constraining layer e.g., thin aluminum sheet
  • the entire upper surface of the ski may be provided with the strip of damping material, although satisfactory results are obtained by applying the damping material in a strip extending longitudinally from the bindings to the front touchdown point of the ski.
  • a 32-inch (approximately 81 cm.) long damping strip has been found extremely suitable.
  • the viscoelastic layer has aggressive pressure-sensitive adhesive characteristics, facilitating attachment of the damping strip and permitting removal if and when desired. It is also contemplated, however, to employ a viscoelastic layer which lacks adequate adhesiveness, a separate pressure-sensitive or other adhesive being used to bond the viscoelastic layer to the upper surface.
  • Suitable viscoelastic materials may be based on polyisobutylene. Particularly preferred, however, are copolymers af alkyl acrylate and one or more copolymerizable acrylic monomers such as acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide.
  • the alkyl acrylate may be a single monomer having about -6-10 carbon atoms in its alkyl group which is not highly branched, i.e., more than half of the alkyl carbon atoms are in a straight chain terminating at the oxygen bridge.
  • alkyl acrylate is a mixture of monomers
  • their alkyl groups should have an average of about 6-10 carbons, and less than half of the alkyl groups should be highly branched. Because of their age-resistance, affinity for metals, adhesion characteristics and viscoelastic properties at the range of temperatures encountered, copolymers containing -97% isooctyl acrylate and correspondingly 10-3% acrylic acid are especially preferred.
  • the strip of damping materal can be the same width as the ski; alternatively, one or more strips of lesser width, preferably arranged symmetrically can be applied. Likewise, a plurality of damping strips can be superposed and adhered to the ski; in such case, the width of each strip may be the same or, if desired, upper strips may be narrower than lower strips. It is also apparent that for sophisticated skiers, the degree of damping may be tailored to the individual or the snow conditions, damping strips being added or removed as desired. Generally, however, it has been found that a ski which has been damped is more satisfactory to an individual for all skiing conditions.
  • a test has been devised to measure the duration of vibrations set up in a ski.
  • the rear portion of a ski i.e., that portion lying more than 31/2 inches (about 9 cm.) behind the mid point of the ski
  • a light weight vibration pickup is then attached approximately 6 inches (l cm.) to the rear of the front touchdown point.
  • the ski is then set into vibration by lightly plucking the tip, vibration thereafter continuing at the resonant frequency of the ski (which is almost always in the range of -15 HZ.) and gradually dying away.
  • the Output of the vibration pickup is fed into a recorder having a strip chart moved beneath a marking pen at a speed of mm. per second. From the chart, the resonant frequency is calculated and the average height ratio of several succeeding peaks measured, thereby obtaining the average peak to peak decrement ratio.
  • a typical decay rate for a wooden ski is about 15 db/sec.; the vibration decay rates for conventional non-wooden skis are usually in the range of 2-5 db/sec., with a few approaching 15 db/sec. It has been found that, regardless of the nature of the ski to which damping strips made in accordance With this invention are applied, the decay rate can easily be increased by 10-20 decibels per second. -If desired, of course, the dimensions of the strip can be varied t0 achieve a greater 0r lesser degree of damping.
  • the strip is preferably chosen so that the weight increase is held to a minimum.
  • the damping index an arbitrarily selected parameter which is defined as the vibration decay rate increase in db/sec. (compared to a bare ski) divided by the weight of the damping strip in grams.
  • the weight increase does not exceed 200 grams and that the damping index be at least about 0.1,
  • the thickness of the entire damping strip be held to as low a caliper as feasible, the overall thickness preferably being no more than about 0.1 inch (2.5 mm.), not only to minimize Weight but also to facilitate moving the ski sideways through snow. It has been found, however, that it is important for the overall thickness to be at least about 0.02 inch (0.5 mm.) if significant improvement is to be obtained. Satisfactory results have been achieved where the constraining layer is sheet aluminum having a thickness in the range of 0.015-0.050 inch (about 0.4-1.25 mm.) and the viscoelastic layer has a thickness of at least about 0.015 inch (about 0.4 mm.).
  • FIG. l is a side elevational view showing one form of ski made in accordance with the invention.
  • FIG. 2 is a top view of a conventional ski modied in accordance with the present invention.
  • FIG. 3 is an enlarged cross-sectional view of a portion of the ski shown in FIG. 2, taken along section lines 3*3.
  • FIG. l depicts a ski 10 having a body portion 11, the lower surface of which has front touchdown 12 and rear touchdown 13.
  • Damping strip 14 comprises constraining number 15 and viscoelastic layer 16, the latter being firmly adhered to the upper surface of body 11.
  • Numeral 17 designates the general location where a ski boot (not shown) is attached when ski 10 is used.
  • FIGS. 2 and 3 depict a ski 10a having body 11a, with front touchdown 12a and rear touchdown 13a.
  • damping strips 14a each individually similar to damping strip 14 as shown in FIG. l, comprising constraining member 15a and viscoelastic layer 16a. Damping strips 14a extend longitudinally from approximately the forward portion of boot location 17a to front touchdown 12a.
  • a glass fiber-filled 95.5:4.5 isooctylacrylate: acrylic acid copolymer, for use as a viscoelastic material in practicing the invention was prepared in accordance with Example 1 of Kalleberg and Turner U.S. Pat. 3,062,683 and knife-coated on a glassine-kraft paper carrier web having a silicone-treated release surface on both sides.
  • the coated carrier web was dried in an air-circulating oven at about C. for 2 minutes, 155 C. for 3 minutes and finally about C. for 6 minutes to provide a dried coating about 1 mil (25 microns) thick, whereupon the coated carrier web was Wound upon itself in roll form for storage.
  • the glass fibers have no appreciable effect on these values and can, l desired, be omitted; the fibers serve primarily to prevent any tendency ofthe viseoelastie material to ooze.
  • Dynamic shear stiffness is calculated for a given viscoelastic layer by dividing the dynamic shear modulus by the stiffness. Glass transition temperature, determined by refractive index measurements, was -71 C.
  • Damping strips were prepared as follows: A 30-inch diameter rnetal roll was wrapped with S-mil (0.127 mm.) biaxially-oriented and heat-set polyethylene terephthalate (polyester) film. The roll was then rotated while' the coated carrier web was pressed against the film by a spring-loaded From the foregoing table it is observed that a 0.016 (0.41 mm.) aluminum restraining layer is not quick enough to obtain optimum results. It is inferred that it stretches slightly, thereby diminishing the effect of the visoelastic material. The' 0.032 (0.81 mm.) aluminum layer, how- 5 ever, is eminently satisfactory and olers a clear cut weight savings over the 0.040 (1.02 mm).
  • isooctyl acrylate acrylic acid copolymer viscoelastic adhesive] to several type's of skis.
  • the coated liner was then placed on a table, coated side up, se'veral Widths of 32-inch long 7075T6 aluminum strips, ranging from 0.016 to 0.040 inch (approximately 0.4 to 1 mm.) thick, placed on the coated surface, :and the damping material and liner trimmed to size with a razor blade.
  • the Youngs modulus for 7075T6 aluminum strips is approximately 7,000,000 kg./ cm2; stretching stiffness is calculated as the product of Ski construction 3,537,717 7 8 width are likewise effective.
  • skis tested were the same 7' down point, at least one elongated strip of a damping maas those listed in Table I, the constraint layer being 0.032- terial comprising in combination: inch (0.81 mm.) aluminum in all cases.
  • the method of reducing the normal tendency of a ski to chatter and vibrate on rough or icy substrates comprising applying to the upper surface of said ski, in an area lying between the bindings and a touchdown point, at least one strip of a damping material comprising in combination:
  • viscoelastic layer having:
  • a ski having laminated to the upper surface thereof, in an area lying between the bindings and the front touchthe ski, said viscoelastic layer having a thickness of at least about 0.4 mm. and at temperatures throughout the range of 25 C. to -1-5" C. and frequencies of 10-20 Hz., a loss tangent of at least 0.5 and a dynamic shear modulus in the range of 0.7-700 kg./cm.2,
  • a constraining layer laminated to the upper surface of the viscoelastic layer said constraining layer having a dynamic stretching stiffness at least l0 times as great as the dynamic shear stiffness of said viscoelastic layer, the overall thickness of said damping material being 0.5-2.5 mm.

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US780088A 1968-11-29 1968-11-29 Damped ski and method of making Expired - Lifetime US3537717A (en)

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US78008868A 1968-11-29 1968-11-29

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US3537717A true US3537717A (en) 1970-11-03

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US (1) US3537717A (enrdf_load_stackoverflow)
JP (1) JPS4932377B1 (enrdf_load_stackoverflow)
CH (1) CH525012A (enrdf_load_stackoverflow)
DE (1) DE1960684A1 (enrdf_load_stackoverflow)
FR (1) FR2024542A1 (enrdf_load_stackoverflow)

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844576A (en) * 1973-07-18 1974-10-29 Olin Corp Vibration damped ski
DE2434423A1 (de) * 1973-07-18 1975-02-06 Olin Corp Schwingungsgedaempfter ski
US3901522A (en) * 1973-07-18 1975-08-26 Olin Corp Vibration damped ski
US4293142A (en) * 1979-07-16 1981-10-06 K-2 Corporation Vibration damped ski
JPS57175375A (en) * 1980-02-21 1982-10-28 Sukii Roshiniyoru Sa Ski with vibration damper
JPS57177783A (en) * 1981-04-09 1982-11-01 Sukii Roshiniyoru Sa Ski
WO1985001220A1 (en) * 1983-09-20 1985-03-28 Koleda Michael T Vibration damping units and vibration damped products
US4563020A (en) * 1982-06-11 1986-01-07 Skis Dynastar Sa Ski vibration damper
US4577886A (en) * 1984-07-26 1986-03-25 Chernega John O Adjustable flex ski
US4639009A (en) * 1985-12-30 1987-01-27 Olin Corporation Snow ski with elastomeric sidewalls
US4696487A (en) * 1985-10-07 1987-09-29 Girard Donald A Ski which is stiff in torsion and relatively weak in beam
US4865345A (en) * 1984-12-27 1989-09-12 Skis Rossignol S.A. Vibration damper for ski
US4895388A (en) * 1988-05-17 1990-01-23 Richmond William D Pair of skis
US5026086A (en) * 1988-11-04 1991-06-25 Salomon S.A. Device for absorption of shocks and vibrations between a ski and a binding
EP0478196A1 (en) * 1990-09-24 1992-04-01 Minnesota Mining And Manufacturing Company Vibration damper having extended temperature range
US5203583A (en) * 1988-11-07 1993-04-20 Salomon S.A. Ski furnished with front masses of inertia
US5288097A (en) * 1987-02-27 1994-02-22 Salomon S.A. Process for manufacturing a ski, and a ski manufactured by the process
US5333889A (en) * 1991-11-25 1994-08-02 Skis Rossignol S.A. Board for sliding, provided with a device for damping vibrations
US5342077A (en) * 1990-07-30 1994-08-30 Skis Rossignol S.A. Snow surfboard having asymmetric characteristics
US5421574A (en) * 1989-08-28 1995-06-06 Toray Industries, Inc. Sports instrument and impact-absorbing element to be attached to sports instrument
EP0682962A1 (de) 1993-02-23 1995-11-22 HTM Sport- und Freizeitgeräte Aktiengesellschaft Schwingungsdämpfungseinrichtung
US5605511A (en) * 1992-08-05 1997-02-25 Callaway Golf Company Golf club head with audible vibration attenuation
WO1997011751A1 (en) * 1995-09-26 1997-04-03 Floreani, Richard Sliding device dampener
US5775715A (en) * 1995-08-01 1998-07-07 K-2 Corporation Piezoelectric damper for a board such as a snow ski or snowboard
US5984343A (en) * 1997-04-08 1999-11-16 Robert J. Harrington Sliding apparatus having adjustable flexion and torsion characteristics
US6095547A (en) * 1995-08-01 2000-08-01 K-2 Corporation Active piezoelectric damper for a snow ski or snowboard
US6113113A (en) * 1994-04-08 2000-09-05 Robert J. Harrington Sliding apparatus having adjustable flexion and torsion characteristics
US6182998B1 (en) * 1995-12-04 2001-02-06 Salomon S.A. Shock-absorbing device for a ski or the like
US20030234513A1 (en) * 2002-01-24 2003-12-25 Skis Rossignol Sa Snow skis
US20040217577A1 (en) * 2003-04-30 2004-11-04 Skis Rossignol Sa Snow skis

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2294724A1 (fr) * 1974-12-20 1976-07-16 Arai Fusaji Ski, en particulier pour courses de descente
DE2709517A1 (de) * 1977-03-04 1978-09-07 Fritzmeier Kg Georg Ski
FR2527460B1 (fr) * 1982-05-27 1986-07-04 Dynamic Perfectionnement aux skis du type a noyau en matiere synthetique cellulaire
AT382318B (de) * 1982-10-19 1987-02-10 Caber Italia Ski
DE3527996C2 (de) * 1985-08-03 1994-06-23 Mankau Dieter Ski mit Ausgleichselementen
FR2611518B1 (fr) * 1987-02-27 1989-11-17 Salomon Sa Ski a amortissement reparti
DE3825188A1 (de) * 1987-08-18 1989-03-02 Blizzard Oesterreich Ges M B H Ski
AT395946B (de) * 1988-12-23 1993-04-26 Tyrolia Freizeitgeraete Skibindung
AT390886B (de) * 1988-07-18 1990-07-10 Fischer Gmbh Skipaar, insbesondere alpinskipaar
FR2638649B1 (fr) * 1988-11-07 1991-01-11 Salomon Sa Ski muni de masses d'inertie laterales
DE3840553A1 (de) * 1988-12-01 1990-06-07 Blizzard Gmbh Ski mit einem daempfungselement
WO1991003284A1 (fr) * 1989-08-28 1991-03-21 Toray Industries, Inc. Articles de sport et materiau amortissant les chocs applique sur les articles de sport
AT402157B (de) * 1990-08-07 1997-02-25 Varpat Patentverwertung Plattenförmige dämpfungseinrichtung für eine schibindung

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2264535A (en) * 1939-06-17 1941-12-02 William Rhodes Davis Ski with metal facing on the running surface
US2995379A (en) * 1958-12-30 1961-08-08 Head Howard Ski
US3194572A (en) * 1960-12-07 1965-07-13 Fischer Josef Laminated ski
US3300226A (en) * 1964-09-28 1967-01-24 Jr Charles L Reed Ski construction and method for varying the flexibility thereof
US3475035A (en) * 1967-02-17 1969-10-28 Mobay Chemical Corp Polycarbonate plastic skis

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2264535A (en) * 1939-06-17 1941-12-02 William Rhodes Davis Ski with metal facing on the running surface
US2995379A (en) * 1958-12-30 1961-08-08 Head Howard Ski
US3194572A (en) * 1960-12-07 1965-07-13 Fischer Josef Laminated ski
US3300226A (en) * 1964-09-28 1967-01-24 Jr Charles L Reed Ski construction and method for varying the flexibility thereof
US3475035A (en) * 1967-02-17 1969-10-28 Mobay Chemical Corp Polycarbonate plastic skis

Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2434423A1 (de) * 1973-07-18 1975-02-06 Olin Corp Schwingungsgedaempfter ski
US3901522A (en) * 1973-07-18 1975-08-26 Olin Corp Vibration damped ski
US3844576A (en) * 1973-07-18 1974-10-29 Olin Corp Vibration damped ski
US4293142A (en) * 1979-07-16 1981-10-06 K-2 Corporation Vibration damped ski
JPS57175375A (en) * 1980-02-21 1982-10-28 Sukii Roshiniyoru Sa Ski with vibration damper
JPS57177783A (en) * 1981-04-09 1982-11-01 Sukii Roshiniyoru Sa Ski
US4438946A (en) * 1981-04-09 1984-03-27 Skis Rossignol S.A. Slalom ski with vibration damper
US4563020A (en) * 1982-06-11 1986-01-07 Skis Dynastar Sa Ski vibration damper
US4627635A (en) * 1983-09-20 1986-12-09 Koleda Michael T Vibration damping units and vibration damped products
WO1985001220A1 (en) * 1983-09-20 1985-03-28 Koleda Michael T Vibration damping units and vibration damped products
US4577886A (en) * 1984-07-26 1986-03-25 Chernega John O Adjustable flex ski
US4865345A (en) * 1984-12-27 1989-09-12 Skis Rossignol S.A. Vibration damper for ski
US4995630A (en) * 1984-12-27 1991-02-26 Skis Rossignol S. A. Vibration damper for ski
US4696487A (en) * 1985-10-07 1987-09-29 Girard Donald A Ski which is stiff in torsion and relatively weak in beam
US4639009A (en) * 1985-12-30 1987-01-27 Olin Corporation Snow ski with elastomeric sidewalls
US5288097A (en) * 1987-02-27 1994-02-22 Salomon S.A. Process for manufacturing a ski, and a ski manufactured by the process
US4895388A (en) * 1988-05-17 1990-01-23 Richmond William D Pair of skis
US5026086A (en) * 1988-11-04 1991-06-25 Salomon S.A. Device for absorption of shocks and vibrations between a ski and a binding
US5203583A (en) * 1988-11-07 1993-04-20 Salomon S.A. Ski furnished with front masses of inertia
US5421574A (en) * 1989-08-28 1995-06-06 Toray Industries, Inc. Sports instrument and impact-absorbing element to be attached to sports instrument
US5342077A (en) * 1990-07-30 1994-08-30 Skis Rossignol S.A. Snow surfboard having asymmetric characteristics
US5118562A (en) * 1990-09-24 1992-06-02 Minnesota Mining And Manufacturing Co. Vibration damper having extended temperature range and low temperature shock resistance
EP0478196A1 (en) * 1990-09-24 1992-04-01 Minnesota Mining And Manufacturing Company Vibration damper having extended temperature range
US5333889A (en) * 1991-11-25 1994-08-02 Skis Rossignol S.A. Board for sliding, provided with a device for damping vibrations
US5605511A (en) * 1992-08-05 1997-02-25 Callaway Golf Company Golf club head with audible vibration attenuation
EP0682962A1 (de) 1993-02-23 1995-11-22 HTM Sport- und Freizeitgeräte Aktiengesellschaft Schwingungsdämpfungseinrichtung
US6113113A (en) * 1994-04-08 2000-09-05 Robert J. Harrington Sliding apparatus having adjustable flexion and torsion characteristics
US5775715A (en) * 1995-08-01 1998-07-07 K-2 Corporation Piezoelectric damper for a board such as a snow ski or snowboard
US6095547A (en) * 1995-08-01 2000-08-01 K-2 Corporation Active piezoelectric damper for a snow ski or snowboard
WO1997011751A1 (en) * 1995-09-26 1997-04-03 Floreani, Richard Sliding device dampener
US6182998B1 (en) * 1995-12-04 2001-02-06 Salomon S.A. Shock-absorbing device for a ski or the like
US5984343A (en) * 1997-04-08 1999-11-16 Robert J. Harrington Sliding apparatus having adjustable flexion and torsion characteristics
US20030234513A1 (en) * 2002-01-24 2003-12-25 Skis Rossignol Sa Snow skis
US7011332B2 (en) * 2002-01-24 2006-03-14 Skis Rossignol Sa Snow skis
US20040217577A1 (en) * 2003-04-30 2004-11-04 Skis Rossignol Sa Snow skis
US7264262B2 (en) * 2003-04-30 2007-09-04 Skis Rossignol Sa Snow skis

Also Published As

Publication number Publication date
FR2024542A1 (enrdf_load_stackoverflow) 1970-08-28
DE1960684A1 (de) 1970-06-18
JPS4932377B1 (enrdf_load_stackoverflow) 1974-08-29
CH525012A (de) 1972-07-15

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