WO1997026960A1

WO1997026960A1 - In-line roller skate with improved lean angle

Info

Publication number: WO1997026960A1
Application number: PCT/US1997/001152
Authority: WO
Inventors: Steven D. Kimmell; Thomas Baumann; Arthur Dale Baker
Original assignee: Rollerball International, Inc.
Priority date: 1996-01-26
Filing date: 1997-01-27
Publication date: 1997-07-31
Also published as: AU1583097A

Abstract

An in-line skate includes a plurality of wheels (12, 14). Each of the wheels has an axis of rotation (295), with the axis of rotation being located in a vertical plane (defined with respect to a skating surface) through the wheel; a generally spherical outer periphery (293) and an indentation at each (292) location at which the axis of rotation traverses the generally spherical outer pheriphery. Each of the indentations has an outer edge. The skate further comprises a pair of arms (291) coupled to each of the wheels. Each arm of the pair of arms is coupled to its associated wheel inside one of the indentations such that (i) the aforementioned vertical plane passes through the pair of arms and (ii) a plane tangent to the outer periphery of the wheel and perpendicular to a radius of the wheel which lies in the aforesaid vertical plane and which intersects the edge of the indentation does not intersect any portion of the arm.

Description

IN-LINE ROLLER SKATE WITH IMPROVED LEAN ANGLE

This is a continuation-in-part of U.S. Patent Application Serial No. 08/299,234, to Kimmell et al., filed August 31 , 1994, which is incorporated herein in its entirety by reference.

Field of the Invention The present invention relates generally to roller skates and in particular to roller skates having in-line, generally spherical shaped wheels which allow a skater to lean or incline the skate to a relatively large degree.

Background of the Invention

Early roller skate designs employed generally disk-shaped wheels having relatively narrow outer peripheral surfaces defining the rolling surfaces. The rolling surfaces are the surfaces of the wheels which contact the floor or ground during a controlled roll on the floor or ground.

The rolling surface of a typical conventional wheel design abruptly ends at each side wall of the wheel. Thus, if a skater leaned too far to one side while skating, the rolling surfaces of the skate wheels would lose contact with the floor or ground, causing the skater to lose control and/or fall to that side.

Various prior roller skate designs employed four of such disk-shaped wheels supported on a pair of axles. Two wheels were supported on one axle mounted toward the front of the skate and two wheels were supported on the other axle mounted toward the back of the skate. Early roller skate wheels were made of generally hard materials ,such as steel or ceramic materials. More modern roller skate wheels have been made of a softer rubber or plastic material.

Recently, "in-line" skates have become popular. These "in-line" skates have, for example, four generally disk-shaped wheels, each supported on its own axis, arranged in a line along the length of the skate, in various "in-line" skate designs, the mounting brackets for coupling the wheels and axles to the shoe part extend adjacent the side walls of the wheels. The location of these mounting brackets tends to allow portions of the bracket to scrape the ground or floor, if the skater where to lean the skate too far to either side. The "lean angle", the angle of inclination measured from the vertical, is severely limited by the wheel mounting bracket, as well as by the generally disk-like shape of the wheels.

"In-line" skates having wheels which appear to be more spherical, or to be wider than typical disk-shaped wheels, have been disclosed, for example, in U.S. Pat. No. 4,034,995, to Forward et al. (generally spherical wheels), U.S. Pat. No. 3,936,061 , to Wada (wide disk), and U.S. Pat. No. 2,529,314, to Schmid (wide disk). "In-line" skates can, to some extent, give the skater a riding sensation which is closer (relative to the two wheels-per-axle roller skates) to that of riding on ice skates. Typical ice skates are provided with a thin blade for contacting the ice. Generally, the bottom edge of the thin blade can remain in contact with the ice, even when the skater leans the skate to one side, e.g., during a high-speed turn. However, as discussed above, typical "in-line" roller skates cannot be leaned to a significant degree to one side without scraping the wheel bracket against the ground and/or without the user's ankles collapsing inward and the rolling surface of the wheels losing contact with the ground, as discussed above. Thus, typical "in-line" skates still do not provide performance characteristics equal to or near those provided by ice skates. As in-line skates become more and more popular, skaters will demand higher performance equipment. As sports such as roller hockey grow, skaters will need lighter weight, more durable and higher performance skates. As such, the need for such equipment is on the rise.

Along with a demand for higher performance, the growing popularity of in-line skating has also motivated studies of the mechanics of in-line skating. It has been found that when an in- line skater accelerates, he thrusts against the ground with one foot while riding on the other. The more fully the skater can extend his thrusting leg, the longer the duration of the powering stroke, and thus, the greater the acceleration. Conventional in-line skates, however, limit the extension of the leg due to the fact that, at a comparatively shallow angle, the contact surface of the wheel (the "tread") ends. The skater cannot push against the side wall of the wheel, and thus must change sides and thrust with his other foot in order to continue accelerating.

Also, when the skate itself is used as a brake, rather than a separate braking element, the usual practice is to turn the foot, or feet, so as to drag the sides of the wheels against the skating surface (the "T-stop" or "hockey stop"). This is often done by putting the trailing foot down, sideways to the direction of travel, and pressing down. The leading leg is extended at the same time. The greater the lean angle, and thus the farther rearward the trailing leg can be extended, the lower the center of gravity of the skater and thus the safer and more effective the braking process becomes.

A need exists for an in-line skate that maximizes the effective skating surface and the lean angle, in order to afford maximum acceleration and braking ability. Summary of the Preferred Embodiments

In accordance with one aspect of the present invention there is provided an in-line skate comprising a plurality of wheels. Each of the wheels has an axis of rotation, with the axis of rotation being located in a vertical plane (defined with respect to a skating surface) through the wheel; a generally spherical outer periphery; and an indentation at each location at which the axis of rotation traverses the generally spherical outer periphery. Each of the indentations has - - an outer edge. The skate further comprises a pair of arms coupled to each of the wheels. Each arm of the pair of arms is coupled to its associated wheel inside one of the indentations such that (i) the aforementioned vertical plane passes through the pair of arms and (ii) a plane tangent to the outer periphery of the wheel and perpendicular to a radius of the wheel which lies in the aforesaid vertical plane and which intersects the edge of the indentation does not intersect any portion of the arm.

In a more particular embodiment, the skate further includes a chassis, and the pairs of arms are integral with the chassis, that is, form a single piece together with the chassis. The pairs of arms can also be separate elements that are affixed to the chassis. The arms can further be single elements, or can be comprised of a plurality of separate elements that are fastened together. For example, the arms can comprise flat or curved arm portions together with bushings or other segments which extend into the indentations of the wheels to couple therein with the wheels.

In accordance with another aspect of the present invention, there is provided a skate having wheels and pairs of arms as described above. The pairs of arms are coupled to the wheels such that the skate is capable of achieving a lean angle of at least about 60°, preferably at least about 64°. In accordance with still other aspects of the present invention, trucks are provided comprising yokes and wheels coupled together in the manners described above. Skates are also provided which include a chassis and a plurality of yokes permanently, or removably, affixed thereto.

Other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.

Brief Description of the Drawings The detailed description will be made with reference to the accompanying drawings, wherein like numerals designate corresponding parts in the several figures. Figure 1 is a left side perspective view of a left skate of an embodiment of the present invention, illustrating a two wheeled skate having a chassis, a brake and a shoe portion. Figure 2 is a front elevational view of the skate of Figure 1 .

Figure 3 is a perspective view of a wheel of the present invention, with line A-A indicating the axis of the wheel and line B-B lying in the equatorial plane of the wheel. Figure 4a is a cross sectional view of a first embodiment of a wheel according to the invention taken along the line A-A of Figure 3 (i.e., an axial cross section), illustrating the lip/shoulder structure.

Figure 4b is an enlarged view of the lip/shoulder structure of Figure 4a, showing the increased outer shell thickness "X" afforded by the lip/shoulder structure.

Figures 4c-e are, respectively, a left view in the B-B plane of Figure 3 (i.e., a left equatorial cross sectional view), an axial view, and a right equatorial cross sectional view, of a particularly preferred aspect of a wheel core according to a first embodiment of the inventive wheel, illustrating the disposition of reinforcing ribs and pin/receptor structures. Figures 5a-b are cross sectional views along line A-A and line B-B, respectively, of Figure 3, illustrating a spool-type core.

Figures 6a-b are cross sectional views along line A-A and line B-B, respectively, of Figure 3, illustrating an "iron cross" type core.

Figures 7a-b are cross sectional views along line A-A and line B-B, respectively, of Figure 3, illustrating a "diamond" type core.

Figures 8a-b are cross sectional views along line A-A and line B-B, respectively, of Figure 3, illustrating an alternative, machined spool-type core.

Figure 9a is a perspective view of the skate of Figure 1 , illustrating a chassis, two wheels and a brake. Figure 9b is a perspective view of the skate of Figure 9a which further includes a "grind plate", more specifically a box plate.

Figure 9c is a perspective view of the skate of Figure 9a which further includes a plurality of rollers affixed transversely to the chassis for facilitating trick skating.

Figure 9d is a perspective view of an alternative embodiment of the skate of Figure 9a which includes means for fastening the skate to a separate article of footwear worn by a skater.

Figure 10 is a bottom view of the skate of Figure 1 .

Figure 1 1 is a rear elevational view of the skate of Figure 1 .

Figure 12 is a perspective view of a second embodiment of a skate of the present invention.

Figure 13 is a perspective view of Figure 12 with a shoe portion removed. Figure 14 is a perspective view of a third embodiment of a skate of the present invention.

Figure 1 5 is a perspective view of Figure 14 with a shoe portion removed.

Figure 16 is a side elevational view of Figure 1 5.

Figure 17 is a perspective view of a fourth embodiment of a skate of the present invention.

Figure 18 is a perspective view of Figure 17 with a shoe portion removed. Figure 19 is a bottom view ©* th* ambmΛ mt αf fφuw ? ?■ Figure 20 is a side elevational view of the embodiment of Figure 17. Figure 21 a is a side elevational view of the chassis of Figure 17.

Figure 21b is a side elevational view of an alternative embodiment of the chassis of Figure 21 a illustrating a sub-frame to which the front two wheels are mounted and which in turn is coupled to the chassis.

Figure 22 is a perspective view of a fifth embodiment of a skate of the present invention. Figure 23 is a side elevational view of the embodiment of Figure 22. Figure 24 is a perspective view of the fifth embodiment of a skate of the present invention with a shoe portion removed. Figure 25a is perspective view of an embodiment of a skate chassis of the present invention to which a plurality of trucks are removably affixed.

Figure 25b is a front elevational view of a skate including the chassis and trucks of Figure 25a.

Figures 26a-b are top and side elevational views of a first embodiment of a skate brake of the invention.

Figures 27a-b are left top and bottom perspective views of a second embodiment of a skate brake of the invention having a flattened bottom portion.

Figures 28a-b are a left perspective and side elevational view, respectively, of a third embodiment of a skate brake of the invention showing a removable brake pad. Figure 29 is a partial sectional view of a skate according to the invention showing the lean angle achieved according to the invention, in which the wheel has arms conforming in shape to the shape of the indentations of the wheel.

Figure 30a-b are sectional views showing a two-part skate chassis which is subsequently joined together with a wheel in a skate according to the invention. Figure 31 is a side sectional view of a preferred embodiment of a wheel and arms according to the invention in which the arms include arm portions and bushings.

Detailed Description of the Preferred Emboriimpnts The in-line skates described herein represent improvements to the skates described in commonly assigned U.S. Patent Applications No. 08/061 ,583, filed May 12, 1993, and No. 07/831 ,392, filed February 7, 1992, which are incorporated herein in their entireties by reference.

In the following detailed description, reference is made to various figures which depict a single improved in-line roller skate. It is to be understood that all such skates are intended to be used with a second similarly constructed roller skate (not shown), such that one skate may be worn on the user's right foot mά H»a OHMT ffraia enty k* worn on the user's left foot. Only one skate is discussed in detail herein, since both the right foot skate and the left foot skate have similar construction (except that the shoe portion of the right skate is preferably configured for a right foot and the shoe portion of the left skate is preferably configured for a left foot). It is further to be understood that each of the plurality of wheels described herein has the same structure. Thus, only one wheel of each embodiment will be discussed in detail unless otherwise noted.

A first embodiment of a skate according to the present invention is shown in Figures 1 , 2 and 3. The roller skate 10 includes a front wheel 12 and a rear wheel 14, a chassis 16 to which wheels 12 and 14 are coupled, a shoe portion 18, and a brake 21 coupled to chassis 16 behind the rear wheel 14. Each of these elements are discussed in further detail below. The Wheels

The present inventors have recognized that light-weight wheels are preferred for maximizing the performance characteristics of the roller skate. However, in an effort to design a light- weight wheel, the structural strength of the wheel should not be significantly compromised.

The exterior surface of wheel 12 is a generally spherical shape. The term "generally spherical" as employed herein is intended to encompass true spheres and similar shapes such as spheroids and ellipsoids, as well as spheres, etc. having flattened and/or indented poles. The generally spherical shape of the wheels 12 and 14 in combination with the configuration of the chassis 16 allows the user to maintain a rolling surface of each wheel on the floor or ground, while leaning the skate by a relatively large degree with respect to a line extending perpendicular to the floor or ground. In addition, the structure of each wheel 12 and 14 is designed to provide high-performance operation and ease of manufacture.

A first preferred embodiment of the wheel is shown in Figure 4a. As shown, a wheel 12 includes a core 20 surrounded by an outer shell 22. The core 20 comprises generally hemispherical halves 26 and 28, which are bonded together in the equatorial plane of core 20 (i.e., in the plane defined by line B-B of Figure 3). The term "generally hemispherical" is used herein in the same manner as the term "generally spherical".

Each generally hemispherical half 26 and 28 further comprises a lip 30 and 32, respectively. Each lip is disposed about the equatorial periphery of the generally hemispherical half. Thus, each lip is in a plane perpendicular to the axis of rotation 24 of core 20. Core halves 26 and 28 are bonded together along lips 30 and 32. The joined lips 30 and 32 function to reduce shear between the core and the outer shell. This acts to prevent detachment of the outer shell from the core. In the particularly preferred embodiment of Figure 4a, one lip (here, lip 30) has defined therein a notch 35, and the other lip (here, lip 32) includes a rim 37. Notch 35 receives rim 37. This structure affords increased strength and stability to the joint formed by bonding core halves 26 and 28. Each core half 26 and 28 further comprises a shoulder 34 and 36, respectively. As shown in more detail in Figure 4b, chord C-C defines shoulders 34 and 36. The distance between chord C-C and the continuation of the outer circumference of core 20 (indicated by the dashed arc C-C), designated "X", which is equivalent to the distance "X"', is the additional thickness of outer shell 22 above the top of lips 30 and 32 afforded by the shoulder structure. This additional thickness is especially advantageous because of the heavy wear that occurs over the equatorial area of wheel 20 in use in a skate. Such wear occurs in particular in skates used by beginning skaters.

In Figures 4c-e, a preferred embodiment of the foregoing wheel core 20 includes a plurality of internal reinforcing ribs 39. On at least a portion of the plurality of ribs 39 are mounted pins 41 and receptors 43. Pins 41 are mounted on one of the core halves (here core half 26), and receptors 43 are mounted on the other core half (here core half 28). Receptors 43 engage pins 41 concurrently with the engagement of rim 37 in notch 35, preventing rotation of core halves 26 and 28 relative to each other.

Core halves 26 and 28 preferably are bonded together as described in more detail below, prior to formation of shell 22 around core 20.

Alternative embodiments of core 20 are illustrated in Figures 5a through 8b. Referring to Figures 5a-b, wheel 12 includes a rigid, spool-shaped core 34 over which is formed outer shell 22. Spool-shaped core 34 can be a unitary structure, as shown in Figure 5a. In the alternative, core 34 can be formed by bonding two half-spools. The core 34 includes a substantially cylindrical axle housing 38 which defines a hollow interior 40 for receiving an axle (not shown). Each end of the axle housing 38 opens into a larger diameter, substantially cylindrical bearing housing 42 and 44, for receiving a wheel bearing member (not shown). For example, for a wheel of 70 mm in diameter, the distance between bearing housings 42 and 44 is preferably about 43 mm, where an axle of substantially 43.5 mm in length (instead of 43 mm, to prevent the bearings from locking when operating within the bearing housings) is housed in the axle housing 38.

The spool-shaped core of Figures 5a-b provides a wheel having a high volume of cover material. Such a wheel provides high performance, having excellent stability and long life. This embodiment would provided the needed performance for skating sports such as hockey. This embodiment, however, has a high wβigfoi. In Figures 6a-b, wheel 12 has a core 48 and an outer shell 22. Core 48 has an "iron cross" axial cross section. More specifically, core 48 defines a generally disk shaped space 50 disposed about axis of rotation 24 at the midpoint of the axle housing 38. This embodiment requires less material for the outer shell 22 but still provides a thick covering at the high wear areas 52 of the wheel 12, which exhibit high wear in skates used by more advanced skaters. The embodiment also provides a substantial outer shell thickness about the equatorial area of the wheel 12.

In Figures 7a-b, wheel 12 has a core 56 and an outer shell 22. Core 56 has a "diamond" (more precisely, truncated diamond or octagonal) axial cross section. In this embodiment, core 56 defines a volume disposed about the axis of rotation 24 and centered at the midpoint of the axle housing 38, which includes a central section 51 and first and second end sections 53 and 55, respectively. Central section 51 defines a space 58 and has a generally cylindrical shape. First and second end sections 53 and 55 have a generally conic frustum shape and are disposed adjacent central section 51. The frustum base radii of first and second end sections 53 and 55 are substantially equivalent, preferably equivalent, to the radius of central section 51. This embodiment also requires less material for outer shell 22 than the embodiment of Figure 5a, but provides a thick covering at the wear areas 68.

The three embodiments illustrated in Figures 5a-b, 6a-b and 7a-b typically do not require reinforcing ribs such as the ribs 39 of the embodiment of Figure 4c-3. Such ribs may be included, if desired. The cores may be unitary, or may be formed from two halves in a manner similar to the embodiment of Figure 4a. These cores may be formed by various processes, preferably by injection molding, as discussed below.

An alternative embodiment of wheel 12 as shown in Figures 8a-b includes core 60 and outer shell 22. Core 60 includes a substantially cylindrical axle housing 62 which defines a hollow interior 64 for receiving an axle (not shown). Each end of the axle housing 62 opens into a larger diameter, substantially cylindrical bearing housing 66 and 68, for receiving a wheel bearing member (not shown). Spool-type core 60 in this embodiment is a machined metal core, such as an aluminum core.

In all of the embodiments of the present invention the outer shell 22 preferably is formed of a material which provides long life with continuous contact and friction on hard surfaces. Particular preferred materials include thermoplastic polyurethanes.

In any of the foregoing or subsequent embodiments of wheel 12, outer shell 22 may be textured or otherwise shaped. In particular, a tread pattern may be formed on at least a portion of the outer surface of outer shell 22. Alternatively, the outer surface of outer shell 22 may include a plurality of facets. Either of these embodiments may provide additional traction and improved performance on irregular skating surfaces, such as tiled floors.

If desired, outer shell 22 may be formed of a material which provides glow-in-the-dark properties. In a preferred embodiment, the material for the outer shell 22 is suitable for injection molding about core 20. Thus, the material should not be too flexible and "rubbery". Furthermore, the material must be suitable for binding to the outer peripheral surface of core 20. If injection molded to the outer peripheral surface of core 20, the material forming outer shell 22 must have a melting point low enough to avoid imparting excessive heat to core 20 during the injection molding process. Excessive heat and subsequent cooling to form outer shell 22 may cause core 20 to deform.

Further, if the melting temperature of the shell material is close to the melting temperature of the core material, shell material might leak into the core. This would result in defective, unbalanced wheels. Therefore, it is preferred that the material chosen for outer shell 22 have a melting point less than the melting point of the material forming core 20. The difference in melting points of the core and outer shell materials preferably is about 40 to 100°F. Higher temperature differentials may be employed depending on the choice of materials, but lower temperature differentials are not preferred.

In a preferred embodiment, wheel 12 is made by injection molding or press forming from a glass-reinforced plastic material. Preferably, the material includes a plastic matrix with a glass load of ranging from approximately 1 5% to approximately 35%.

Plastics suitable for use in forming core 20 include nylon, ABS (acrylonitrile-butadiene- styrene copolymer) and polypropylene. Melting points for nylon 6/6 materials typically ranges from about 425 to 475 °F, and for nylon 6 materials from about 350° to 400°F. Materials suitable for forming outer shell 22 include thermoplastic polyurethanes, typically having melting temperatures from about 385° to 400°F. Other polyurethanes having lower melting temperatures may also be employed.

The following examples of combination of material can be used to produce cores within the present invention.

Table 1

Plastic Matrix % Glass Fiber

Dupont Zytel 8018, Virgin with up to 14.3% 25% Regrind Nylon, Type 6/6

DuPont Zytel 8018, 100% Regrind 14.3% Nylon, Type 6/6

BASF Ultramid B3EG3, Virgin with up 15% to 25% Regrind Nylon, Type 6

BASF Ultramid B3EG7, Virgin with up 35% to 25% Regrind Nylon, Type 6

Impact-modified BASF Ultramid 1 5% B3EG3, Virgin with up to 25% Regrind Nylon, Type 6

Impact-modified BASF Ultramid 35% B3EG7, Virgin with up to 25% Regrind Nylon, Type 6

An exemplary polyurethane material for forming outer shell 22 is BASF Elastolian S85A55 polyurethane polyester base (85 durometer A Shore).

As shown in Figures 1 and 2, the wheel structure, being generally spherical, defines a relatively large outer peripheral surface suitable to make rolling contact with the ground or floor. That is, the generally spherical shape of the outer surface of the wheel defines a relatively large arc which defines the riding surface area of the wheel - the area of the surface which can make controllable rolling contact with the ground or floor. This relatively large rolling surface area allows the axis of rotation 24 of wheel 12 be at a relatively large angle with respect to the plane of the ground or floor and still be operable to roll in a controllable manner along the ground or floor.

This feature allows the skater to lean the skate to a relatively great extent with respect to a line extending perpendicular from the plane of the ground or floor. As a result, the skater has a greater ability to lean into high speed and/or sharp turns and has a greater ability to ride along angled surfaces than the skater would have with conventional disk-shaped wheels discussed above. It is believed that a skilled skater could have the physical ability to lean a skate as far as about 70 degrees from a line p iff— cMln ** tfce btm defined by the ground or floor. provided that the structure of the skate will allow such a lean. Therefore, in a preferred embodiment, the arc is about 140 degrees so as to define a riding surface area of the wheel sufficient to accommodate a lean of up to about 70 degrees. The relatively large arc feature, in combination with the high-strength and light-weight wheel core structure and soft outer cover discussed above, provides a significantly improved high-performance wheel which allows- the skater to maintain a controllable forward or backward movement of the skate, even with the skate at a substantial angle or lean. The resulting sensation felt by the skater is similar to that of an ice skate (which, by virtue of a thin blade adapted to "cut" into the ice, can be leaned or angled relative to the ice surface and still maintain a controllable forward movement). With reference to any of wheel structure embodiments discussed above, a preferred method for making wheels in accordance with the present invention will now be discussed.

In order to produce wheels of accurate dimensions, the core should be formed in accurate dimensions. In a preferred embodiment, core 20 is formed in a molding process or in a pressing process. Accordingly, the material chosen to form core 20 is preferably of the type which is suitable for molding or pressing, yet will not significantly deform or change in dimension during the cooling step of the molding or pressing process, and which provides sufficient strength characteristics to withstand prolonged and rigorous skating, as discussed above.

The ability of the core material to maintain its shape and dimension (and to avoid deformation) during the cooling steps is further advantageous for embodiments, as discussed below, wherein two portions are coupled together to form the core.

A preferred process for making a wheel 12 according to the invention will now be discussed with reference to Figure 4a. As discussed above, outer shell 22 may be formed by injection molding the covering material over core 20 and cooling the outer shell 22. In such embodiments, the material used to form core 20 is preferably of the type which will not significantly deform or cause a change in dimension during the injection molding and cooling steps of forming outer shell 22.

As noted above, in a preferred embodiment, core 20 is formed of two molded or pressed portions 26 and 28. Each portion 26 and 28 includes half of core 20 and a half of axle housing 27. The lips 30 and 32, as well as the equatorial peripheries of core halves 26 and 28, should be accurately dimensioned and free of deformations so as to avoid gaps between the two halves upon bonding. Such gaps could allow the material used to form outer shell 22 to seep into the interior of core 20.

The core halves 26 and 28 may be coupled together using various techniques, including heat sealing, such as inctuøftø laser sealing; iHieti * pending; and sonic welding. Sonic welding is particularly preferred. Sonic welding helps to ensure that the dimensions of core halves 26 and 28 are not altered. Sonic welding further helps to prevent the material used to form outer shell 22 from seeping into the interior of the core during the step of forming outer shell 22 by injection molding. Core halves 26 and 28 are coupled together, such as by sonic welding, to form core 20.

Core 20 typically has a diameter of about 60 mm, which may be greater or less as a matter of design choice. Outer shell 22 is preferably formed about core 20 by injection molding, to provide a thick layer of a softer plastic material, such as a thermoplastic urethane. The maximum pressure for injecting the plastic material into the mold should be selected so as to avoid collapsing core 20. Outer shell 22 is then cooled to form a wheel structure having a typical diameter of 70 mm, which can be greater or less as a matter of design choice.

Those skilled in the art will readily be able to specify various process parameters such as pressures, temperatures, times, etc., as well as select appropriate molding tools, for forming wheel 12. Wheel 12 is then weighed to determine whether any outer shell material seeped into the interior of core 20 during formation of outer shell 22. If wheel 12 weighs more than a predetermined weight (predetermined to be the weight of a wheel with no seepage of the shell material into the core), then the wheel is determined to be defective. The Chassis Referring to Figures 1 , 2, 9a and 10, a first embodiment of a chassis 16 of the present invention is illustrated. The chassis 16 couples the wheels 12 and 14 to the shoe portion 18. In the preferred embodiment shown in the figures, brake 21 is affixed to chassis 16.

The shape of the chassis is preferably designed for strength as well as to allow for a high degree of skate inclination (lean or angle) with respect to the ground or floor without contacting and scraping the ground or floor. Preferably, the width of the chassis 16 is no greater than

(and preferably less than) the maximum width of the shoe portion 18. This allows the chassis

16 to be relatively thin, so as not to contact the ground or floor at high degrees of skate inclination. This also allows the chassis to be formed as a relatively light-weight structure.

The chassis 16 preferably is formed from a material such as glass fiber-reinforced nylon or other materials of similar structural strength. Chassis 16 can also be formed from a metal such as aluminum or steel.

Chassis 16 includes a first pair of arm extensions 70 and 72 to which front wheel 12 is coupled by standard means, such as threaded fasteners. The chassis 16 also includes a second pair of arm extensions 74 and 76 to which back wheel 14 is coupled. Arm extensions 70, 72, 74 and 76 are unitary with fife øβfftiflM* M «*#Φ0. fide portions 78 and 80 are preferably supported by ribs 81 and 83. Side portions 78 and 80 may be curved upwards, between arm extensions 70 and 74 and arm extensions 72 and 76, respectively. This curved section provides a "rail guide" and allows a skater to perform various tricks or stunts such as "rail riding". As illustrated in Figure 9a, holes 82 are provided in at least a portion of the top portion of chassis 16 to receive means, such as threaded fasteners, for fastening chassis 16 to shoe 18. In Figure 9b, "grind plate" 95 is affixed, preferably detachably affixed using appropriate fasteners, to side sections 78 and 80 (not visible). Grind plate 95 serves to facilitate trick skating, such as "rail riding," and also protects side sections 78 and 80 from excessive wear. Grind plate 95 can be configured as a "rail plate," that is, a flat plate affixed separately to each side section 78 and 80, or in the alternative as a "box plate" which wraps around the bottom of chassis 16 and is affixed to both side sections 78 and 80.

Grind plate 95 can be formed from a variety of materials. In a preferred embodiment, grind plate 95 is at least partially comprised of a material having a low coefficient of friction to facilitate sliding. When grind plate 95 becomes excessively worn, it can be replaced with a new grind plate.

In Figure 9c, a plurality of rollers 94 are mounted in side sections 78 and 80 (not visible). Rollers 94 are mounted transversely to the longitudinal axis of chassis 16, and facilitate "rail riding" by the user. Figure 9d illustrates an alternative embodiment of the foregoing skate which includes means for fastening the skate to a separate article of footwear worn by a skater. Skate 1 1 includes wheels 12 and 14 and chassis 16, but rather than boot 18 affixed to chassis 16 includes fastening means such as straps 93 and heel bracket 97. The user thus places a shoe, boot or other article of footwear on his foot, and then contacts the article of footwear with the chassis 16 and the heel bracket 97. Straps 93 then secure the skate 1 1 to the user's shoe or boot. The foregoing alternative embodiment is applicable to any of the various skate configurations described herein.

A second embodiment of chassis 16 is illustrated in Figures 12 and 13. Skate 10 includes three generally spherical wheels 84, 86 and 88. The wheels 84, 86 and 88 preferably have a structure as discussed above. The wheels are affixed to chassis 90 by pairs of extensions 91 in a manner similar to that described with respect to the preceding embodiments. The three- wheeled embodiment affords a faster skate than the two-wheeled embodiment, but is somewhat less maneuverable than the two wheeled skate.

A third embodiment of chassis 16 is illustrated in Figures 14, 15 and 16. Skate 10 includes five generally spherical shaped wheels 96, 98, 100, 102 and 104. The wheels 96, 98, 100, 102 and 104 preferably have a structure as discussed herein. The five wheels are affixed to arm extensions 99 of chassis 16. As with the foregoing three-wheeled skate embodiment, the five-wheeled skate provides a faster skate than the two-wheeled embodiment, and is particularly advantageous as a speed skate. It is preferred that the five-wheeled skate use 62 mm wheels. This provides for a lower center of gravity and easier cross-over.

Any of the foregoing or subsequent embodiments are capable of accommodating wheels 12 having varying diameters. Thus, for example, a set of wheels 12 having a relatively large diameter can be exchanged for another set having a relatively smaller diameter. This can be accomplished by the use of bushing spacers or other spacing means. Figures 1 7-21 a illustrate an embodiment of a skate according to the invention which includes an asymmetrical wheel configuration. Skate 10 includes three generally spherical shaped wheels 108, 1 10, and 1 12. Wheels 108, 1 10 and 1 12 preferably have a structure as discussed above. The wheels are coupled to chassis 16 in the manner discussed above. Ribs 81 and 83 preferably are employed to support side sections 78 and 80 as previously described. As may be seen, wheels 108, 1 10 and 1 12 are asymmetrically placed along the longitudinal axis of chassis 16. "Asymmetric" placement herein denotes that the spacings between adjacent pairs of wheels varies along the longitudinal axis of the skate.

In the embodiment of Figure 17, wheels 108 and 1 10 are coupled near the front of chassis 16, and wheel 1 12 is coupled near the rear of chassis 16. The spacing between wheels 108 and 1 10 is less than the spacing between wheels 1 10 and 1 12.

In a preferred embodiment, wheels 108 and 1 10 have a first diameter and wheel 1 12 has a second diameter which is greater than that of wheels 108 and 1 10. This configuration affords both speed and improved maneuverability. Due to the sizing of the wheels, a conic path is naturally formed as the skate moves along a surface. Therefore, the skate is more inclined to turn. This provides the improved turning characteristics. However, for the same reasons, the skate is generally less stable than a skate having all of its wheels the same size.

A modification of the foregoing asymmetric embodiment includes two wheels, namely a front wheel having a relatively smaller diameter and a rear wheel having a relatively larger diameter. In effect, this embodiment omits the second wheel 1 10 in Figure 17. This configuration is still "asymmetric" in the sense that the wheel diameters differ.

Figure 21 b illustrates an alternative embodiment in which front wheels 108 and 1 10 are coupled indirectly to chassis 16. Front wheels 108 and 1 10 are first coupled to sub-frame 1 13. Sub-frame 1 13 in turn is coupled to chassis 16 in the manner described above with respect to the wheels of preceding embodiments. Rear wheel 1 12 is coupled to chassis 16 in the manner previously described. If desired, other skate configurations as described herein can include one or more sub-frames to which two or more wheels are directly coupled. The sub-frame or sub-frames in turn are coupled to the skate chassis.6

An alternative chassis embodiment for a skate of the present invention is illustrated in Figures 22, 23 and 24. Skate 10 includes two generally spherical shaped wheels 12 and 14, preferably wheels having structures as described herein. The wheels are coupled to chassis 120. Chassis 120 includes front portion 122 and rear portion 124 which extend upwardly from base portion 126 of chassis 120. Front portion 122 and rear portion 124 define localized coupling points 128 and 130 in the front and rear, respectively, for attaching the chassis 120 to a shoe 1 8. The localized coupling points allow the chassis 120 to accommodate various sized shoes. This in turn reduces the manufacturing cost of the skate.

The chassis embodiments discussed directiy above and illustrated in Figures 1 - 23 preferably are formed to be a unitary body. As such, a stable, solid and lightweight chassis may be obtained. In an alternative embodiment applicable to any of the foregoing designs, the chassis can include a base portion and plurality of trucks, including a wheel and a yoke, which are removably affixed to the chassis. Such a chassis permits ready interconversion between various embodiments of the skate having different numbers of wheels and/or wheels of differing diameters.

Referring to Figures 25a-b, a preferred embodiment of the foregoing chassis is illustrated. Chassis 140 includes a base 142 and means for affixing a plurality of yokes thereto. Exemplary means include the pair of rails 144 shown in Figure 25a having defined therein a plurality of openings 146. To chassis 140 are removably affixed a plurality of trucks 147. Truck 147 includes wheel 12 coupled to yoke 148. Yoke 148 includes means for coupling the yoke to chassis 140. As illustrated, exemplary coupling means include a pair of flanges 150 having defined therein corresponding openings 151. Openings 151 are capable of being aligned with pairs of openings 146 in rails 144 and receiving fasteners 152, preferably removable fasteners which can be threaded fasteners such as nut/bolt assemblies. In this way, each truck 147 is coupled, preferably removably, to chassis 140. Other means for coupling the trucks to the chassis will be readily apparent to those skilled in the art and are contemplated as being within the scope of the present invention. The Shoe Portion

As illustrated in Figure 1 , skate 10 includes a shoe portion 18 for receiving a user's foot. Various shoe portion designs for roller skates are well known in the art and are, therefore, not discussed in detail herein. However, in a preferred embodiment of the present invention, the shoe portion 18 is formed as a stiativeiy light-weight, yet high-strength structure. The Brake

As shown generally in Figure 1 , a skate according to the invention preferably includes a brake 21 affixed to the chassis of the skate. Various embodiments of brake 21 are shown in more detail in Figures 26a-b, 27a-b and 28a-b Brake 21 in general is a "U-shaped" member which includes a U-shaped portion 206 comprised of a bottom section 207 and arms 209, and flanges 21 1 which preferably form an obtuse angle with arms 209. Bottom section 207 can be semi-circular or can have other shapes such as a rounded square. The U-shaped portion 206 can have a circular cross-section or another cross-section such as oval, elliptical, square, etc. Flanges 21 1 preferably include at least one mounting hole 213, preferably at least two mounting holes 213 as shown. Brake 21 is affixed to chassis 16 by conventional means such as threaded fasteners.

Brake 21 partially surrounds rear wheel 14, preferably about 130° - 1 50°. This configuration affords multi-directional braking capabilities. The lowest point of bottom section 207 does not touch a surface when the skate is in a level position, but contacts the skating surface when the skate 10 yaws upwards with respect to the axis of rotation of rear wheel 14, or when skate 10 is sufficiently laterally inclined. Brake 21 flexes during use, and thus affords variable, controllable braking.

If desired, brake 21 may be affixed to chassis 16 such that is partially surrounds front wheel 12, rather than rear wheel 14.

Brake 21 may be made of any durable material, as for example a thermoplastic polyurethane.

An alternative embodiment of brake 21 is illustrated in Figure 27a. Bottom portion 209 includes a flattened portion 217 which forms an expanded wear surface, preferably oriented at an angle to the skating surface when brake 21 is affixed to chassis 16. The expanded wear surface provides additional braking power. Flattened portion 217 may be textured with ridges or other textures, if desired. Optional stiffening ribs 215 may be included to provide additional support between arms 209 and flanges 21 1.

In Figures 28a-b, another alternative embodiment of brake 21 comprises two releasably coupled components. Bottom portion 209 has a surface 225 to which brake pad 223 is affixed by removable fastening means 223, such as a threaded fastener. In this embodiment, the U- shaped brake can be formed from a material such as nylon, polypropylene or another similar material, while brake pad 223 preferably is formed from a thermoplastic polyurethane. Brake pad 223 can be replaced when excessively worn. Brake 21 may serve as a stabilizer bar or pivot point during tricks or stunts, in addition to performing its braking function. The brake may also be used with the disk shaped wheels of various in-line skates.

In Figures 29 and 31 , skates according to the invention which achieve improved lean angles (θ) with respect to a vertical plane perpendicular to a skating surface with which the skate is in contact, are illustrated. It is to be recognized that the configurations of wheels and arms illustrated therein are useful with any of the foregoing embodiments as well. For example, wheels having any of the internal structures described herein can be employed. Likewise, any number of wheels and pairs of arms can be selected, and similarly, wheels having varying sizes and spacings can also be selected. Brakes of various sorts, including any of the improved brakes described herein, can be included as well.

In the embodiment of Figure 29, arms 291 are shaped to conform to the shape of indentations 292 and parts of the outer periphery of wheel 293. Arms 291 are coupled to axle 295 of wheel 293. Wheel 293 has axis of rotation A and a radius R that is perpendicular to the skating surface and that intersects the edge of indentation 292 as shown. This wrap¬ around structure affords a lean angle (θ) of at least about 60° .

Use of thinner arms formed from stronger materials, such as titanium, and corresponding reduction in the size of the indentations 292, can afford even higher lean angles, up to 70° to 80° or more. One concern that may arise when arms 291 are formed together with chassis 294, i.e., when the chassis and arms are molded as a single unit, is that it can be difficult to remove the unit from the mold in which it is formed. To overcome this difficulty, the chassis 294 with arms 291 can be formed from two pieces 301 -302 (see Figure 30a) which are subsequently joined together (see Figure 30b). Alternatively, the arms 291 can be formed from arm portions 31 1 to which are affixed bushings 312 (see Figure 31 ). The bushings 312 in turn are coupled to axles 295 of wheels 293 inside indentations 292, and the axles 295 are secured by means of recessed screw heads 296. In this embodiment, the arms 291 include two elements which are joined together to form each single arm. The exemplary indentations 292 of wheels 293 as shown in Figures 29-31 have chamfered edges 297. These chamfered edges can be eliminated to increase the available outer periphery of the wheels, and thus to afford an increase of about 2° in the lean angle (θ). In doing so, it may be useful to modify the wheels 293 by, for example, using stronger bearings.

The skate illustrated in Figures 29-31 thus are characterized by minimal protrusion of the arms 291 from the wheels 293, such that no part of the skate touches the skating surface until the entire outer periphery of the wheels 293 is utilized. The outer periphery, or "tread", of the wheels, which contacts the skating surface, extends far beyond the point at which the tread of a conventional in-line skate wheel ends. A skater thus is able to continue each stroke for a longer period and to realize more continuous acceleration. Due to the greater available tread, traction is increased and maneuverability is correspondingly enhanced. The improved lean angle realized by the inventive skate further shortens the turning radius of the skate and permits turning at higher speeds. The inventive skate also allows greater rearward extension of the skater's leg during braking, with attendant lowered center of gravity. Side braking is thus facilitated.

Claims

What is claimed is: . An in-line skate comprising: a plurality of wheels, each of said wheels having an axis of rotation, said axis of rotation being located in a vertical plane through said wheel; a generally spherical outer periphery; and an indentation at each location at which said axis of rotation traverses said generally spherical outer periphery, each of said indentations having an outer edge; and a pair of arms coupled to each of said wheels, wherein each of said pair of arms is coupled to its associated wheel inside one of said indentations such that (i) said vertical plane passes through said pair of arms and (ii) a plane tangent to said outer periphery and perpendicular to a radius of said wheel lying in said vertical plane and intersecting said edge of said indentation does not intersect any portion of said arm.

2. The skate of claim 1 further comprising a chassis, wherein said pairs of arms are integral with said chassis.

3. The skate of claim 1 further comprising a chassis, wherein said pairs of arms are separate elements and are separately affixed to said chassis.

4. The skate of claim 1 further comprising a chassis, wherein said chassis is comprised of two parts, one of each said pair of arms being integral with one of said two parts of said chassis.

5. The skate of claim 1 wherein said pairs of arms comprise arm portions and bushings, said bushings being affixed to said arm portions and extending into said indentations of said wheels to couple therein with said wheels.

6. An in-line skate comprising:

a plurality of wheels, each of said wheels having an axis of rotation, said axis of rotation being located in a vertical plane through said wheel; a generally spherical outer periphery; and an indentation at each location at which said axis of rotation traverses said generally spherical outer periphery, each of said indentations having an outer edge; and a pair of arms coupled to each of said wheels, wherein each of said pair of arms is coupled to its associated wheel inside one of said indentations such that said skate is capable of achieving a lean angle of at least about 60°.

7. The skate of claim 6 further comprising a chassis, wherein said pairs of arms are integral with said chassis.

8. The skate of claim 6 further comprising a chassis, wherein said pairs of arms are separate elements and are separately affixed to said chassis.

9. The skate of claim 6 further comprising a chassis, wherein said chassis is comprised of two parts, one of each said pair of arms being integral with one of said two parts of said chassis.

10. The skate of claim 6 wherein said pairs of arms comprise arm portions and bushings, said bushings being affixed to said arm portions and extending into said indentations of said wheels to couple therein with said wheels.

1 1 . A truck comprising: a wheel having an axis of rotation, said axis of rotation being located in a vertical plane through said wheel; a generally spherical outer periphery; and an indentation at each location at which said axis of rotation traverses said generally spherical outer periphery, each of said indentations having an outer edge; and a yoke comprising a pair of arms coupled to said wheel, wherein each of said pair of arms is coupled to said wheel inside one of said indentations such that (i) said vertical plane passes through said pair of arms and (ii) a plane perpendicular to a radius of said wheel lying in said vertical plane and intersecting said edge of said indentation does not intersect any portion of said arm.

12. The truck of claim 1 1 wherein said pairs of arms comprise arm portions and bushings, said bushings being affixed to said arm portions and extending into said indentations of said wheels to couple therein

13. An in-line skate comprising

(a) a chassis having a base portion, and

(b) a plurality of trucks of claim 1 1 affixed to said chassis.

14. The skate of claim 13 wherein said plurality of trucks are removably affixed to said chassis.

1 5. A truck comprising: a wheel having an axis of rotation, said axis of rotation being located in a vertical plane through said wheel; a generally spherical outer periphery; and an indentation at each location at which said axis of rotation traverses said generally spherical outer periphery, each of said indentations having an outer edge; and a yoke comprising a pair of arms coupled to said wheel, wherein each of said pair of arms is coupled to said wheel inside one of said indentations such that said truck is capable of achieving a lean angle of at least about 60°.

16. The truck of claim 15 wherein said pairs of arms comprise arm portions and bushings, said bushings being affixed to said arm portions and extending into said indentations of said wheels to couple therein with said wheels.

17. An in-line skate comprising

(a) a chassis having a base portion, and

(b) a plurality of trucks of claim 1 5 affixed to said chassis.

18. The skate of claim 17 wherein said plurality of trucks are removably affixed to said chassis.