STEERABLE WHEEL ASSEMBLY WITH DAMPING AND CENTERING FORCE MECHANISM FOR AN IN-LINE SKATE OR ROLLER SKI

Abstract: A steerable wheel assembly for an in-line skate or roller ski comprises a hollow or dish-shaped wheel (11), a wheel bearing (13), and a wheel support (14) connecting the wheel (11) to a steering pivot (16) which is substantially disposed at a distance measured radially from the rotational axis of the wheel (11) where that distance is greater than the outer radius of the wheel bearing (13) and less than the outer radius of the wheel (11). Steering of the wheel occurs as the user's weight is displaced or the chassis of the device is inclined with respect to the ground toward the desired turning direction. A chassis for an in-line skate or roller ski containing a damping and centering force mechanism which may be used to moderate the behavior of a steering mechanism or suspension mechanism comprises a structural member (21), a damper housing (17), a damper piston (19), a fluid chamber (24), and a centering force means (18). When the steerable wheel assembly is coupled with the chassis with internal damping and centering force mechanism, a sporting device with improved handling and maneuverability is provided. A flex spring (31) may provide steering, self-centering and spring suspension in a single assembly. Brakes such as drum or disk brakes connected to one or more wheels may be provided with a boot-actuated cable assembly.

Description: STEERABLE WHEEL ASSEMBLY WITH DAMPING AND CENTERING FORCE MECHANISM FOR AN IN-LINE SKATE OR ROLLER SKI FIELD OF THE INVENTION The invention pertains to wheeled recreational devices such as skates, land skis and skate boards. Many wheeled devices have been invented with varying degrees of public acceptance and popularity. Some of the most widely known are for sport and recreation, such as roller skates. Although very functional and popular, roller skates steer using a bulky mechanism which requires wheels to be in pairs. This allows them to have a certain degree of stability as well as steerability, but makes them heavier than ideal, and limits their overall performance in terms of speed, handling, and the range of terrain on which they may be used. Certain performance gains and wider usage have come from the introduction of in-line skates. These are faster, more maneuverable, and potentially lighter. However, they do not actually steer by weight displacement (although they may at first appear to do so). Steering of in-line skates is accomplished by actually scrubbing the wheels and twisting the skate relative to its direction of motion, i.e. , by misalignment of the wheel to introduce lateral frictional force. This works well only with wheel configurations that have a relatively short wheelbase, typically shorter than the users foot, or that have central wheels which are lower than the other wheels, creating an effective wheelbase which is short enough to allow turning - a configuration commonly referred to as rocker. For configurations with only two wheels and/ or longer wheelbases, steering by scrubbing the wheels is much more difficult. Examples of such devices include land skis, roller skis, and some of the recently introduced all terrain "off-road" in line skates. Typically with these devices steering is accomplished by step turning, which is clumsy and difficult. Handling could be greatly improved if steering were accomplished by some form of weight displacement steering similar to that of downhill skis. A wide variety of mechanisms exist for steering individual wheels of sporting devices by weight displacement. However, the known methods have drawbacks which have prevented them from being adopted for in-line skates or land skis, as discussed below. U.S. patent 4,382,605 to Hegna, 1983 relies on a chassis comprised of multitude of flexible members which bend and result in steering when the user's weight is shifted. This is complex from a manufacturing standpoint, and potentially unwieldy when used on a foot mounted device such as an in-line skate, roller ski, or the like. The mechanism described in U.S. patent 3,876,217 to Copier, 1975 and the similar mechanism used in practice on wheeled land surfing boards both allow the front wheel of a device to pivot about an axis defined by a pivot which is located relatively forward of the front wheel axle. This mechanism is unwieldy because the user's weight is applied to the frame from behind the front wheel, which requires substantially large and potentially heavy supporting members connecting the weight bearing portion of the frame to the pivot, and additional members to transfer forces between the pivot and the axle of the front wheel. In both these cases these members form a fork around the front wheel. With the fork, and the additional length of frame required to connect to it, the overall device weight is substantially greater than if the frame could connect directly to the axles of the wheels. U.S. Patent 4,138,127 to Kimmell and Stansbury, 1979 describes a mechanism which uses cradle members to provide steering action to wheels of an in-line wheeled device. These cradle members also require a load bearing frame structure which extends to the side of the wheel away from where the user's weight is principally applied in order to create a pivot with the cradle; for example, for a front wheel, the frame must extend beyond the front of the wheel even though the user's weight is primarily located behind the front wheel. For a device with large wheels, this type of mechanism would require a potentially unwieldy frame structure, similar to those described above. U.S. Patent 5,372,383 to Kubierschky, 1994 describes a mechanism which is largely incorporated into the inside of an in-line wheel to provide steering by weight displacement. This mechanism has several disadvantages. As in the case of U.S. 4,138,127, this mechanism requires link members which could be unwieldy for devices with large wheels. Secondly the total amount of steering pivot action obtainable is small because it is limited to the maximum angle obtainable between an axle shaft and an axle tube that surrounds it. For a device with a relatively long wheel base, this would limit the user to large radius turns. Finally, the wheel bearings must be large enough to fit around the axle tube, which would in many cases, prohibit the use of the inexpensive small skate bearings which have become the industry standard. U.S. Patents 5,199,727 to Lai, 1993 and 5,443,277 to Kubierschky, 1995 describe mechanisms for the same purpose which are both fully contained inside the wheel, and eliminate some of the bulk of the previously mentioned methods. Although they do not require the use of bulky links or cradles, these mechanisms have the following disadvantages: a) Some if not all of the functional parts of these mechanisms must fit within the inner race of the wheel bearings (as the wheel is viewed from the side). This again necessitates the use of wheel bearings which are larger, heavier and probably more expensive than standard skate bearings. b) These mechanisms do not lend themselves to the use of standard, inexpensive skate or skateboard wheel bearings for the steering pivot elements because of space constraints. c) Both mechanisms are limited in total pivot range because of arrangements similar to those of U.S. 5,372,383, of a stationary shaft body enclosed by a hollow axle tube body that pivots with the wheel. d) Finally, the mechanism of U.S. patent 5,199,727 is subject to having harmful grit and other foreign matter enter into the mechanism unless an elaborate sealing mechanism is added. It would therefore be desirable to provide a versatile and steerable wheel assembly which provides steering control through weight displacement, and optionally provides centering and damping forces to moderate the steering behavior. It would further be desirable to provide such an assembly adapted to diverse skates or similar devices that could benefit from the ability to steer by weight displacement. Accordingly, among several objects and advantages to be addressed by the present invention are one or more of the following: a) to provide a mechanism for steering by weight displacement or inclination with respect to the ground which fits within the radius of the wheel and allows the use of standard skate bearings or relatively simple and fungible bearing or bushing assemblies for the primary wheel bearings and for any steering pivot; b) to provide a steering mechanism which allows a much larger steering pivot range than achieved by other mechanisms that can fit inside a wheel of a skate or roller ski; c) to provide a steering mechanism that is easily sealed against grit and other foreign material; d) to provide a steering mechanism of low or minimal weight; e) to provide a steering mechanism that requires a supporting frame on only one side of the wheel (i.e. with a cantilevered axle) thus reducing the structural complexity and weight of the device; f) to provide a steering mechanism that fits primarily inside the cavity of the wheel of a device so that it is well protected from potentially destructive impact; g) to provide a damping and centering force mechanism to moderate steering behavior, and which preferably fits within and is protected by the frame of the device; h) to provide a steering mechanism which can easily be coupled with an adjustable damping and centering force mechanism capable creating a damped, self centering system to improve handling and maneuverability; i) to provide a damping and centering force mechanism that can be incorporated into the chassis of a device to be easily coupled with a steering mechanism or other mechanism while adding rninimal weight and complexity to the device; j) to provide a steering mechanism which can be easily disabled by the user so that the rotational axis of the wheel is temporarily fixed with respect to the frame of the device; and k) to provide a sporting device such a skate or roller ski with a simple chassis that is disposed to one side of the foot to provide maximum strength and ground clearance, ease of manufacture, and minimum weight and complexity. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings. SUMMARY OF THE INVENTION One or more of the foregoing objects are achieved in accordance with the present invention by a steerable wheel mechanism for a sports device, that includes a wheel, a wheel bearing, and a wheel support which is pivotally connected to a chassis by a pivot assembly substantially contained or centered inside the wheel, and configured to provide improved, weight responsive maneuverability with a compact mechanism. A damping and centering force mechanism internal to the chassis of the sports device may be used in conjunction with the steerable wheel mechanism to provide improved handling, and includes a damper housing incorporated in the chassis, a damping piston, and optionally a centering force element such as a spring or elastomeric member. The damping piston may be a spherical member, and the assembly may employ air as the damping fluid. As applied to a sporting device to be used in pairs with one mounted to each foot, such as a skate or roller ski, each device includes two or more wheels and a chassis having a primary structural member that runs along one side of the foot to provide strength, steering and ground clearance, simplicity, light weight, and ease of manufacture. A brake mechanism may be actuated by the user's boot, and preferably brakes the rear wheel. BRIEF DESCRIPTION OF THE DRAWINGS These and other features of the invention will be understood from the description and claims herein, taken together with the Figures illustrating representative embodiments and details of construction thereof, wherein: Figs 1A to 1C show prior art sporting devices either with a conventional steering mechanism or no steering mechanism, depending on the device. Fig 1A shows a typical roller ski without steering. Fig IB shows an all terrain in line skate without a steering mechanism, which is typical. Fig 1C shows a land surfing device. Figs 2A to 2C show the preferred embodiment of a ski / skate sporting device configured with the steering, damping, and centering force mechanisms of the present invention. In these figures, the wheel being steered is the front wheel, and a damping / centering force mechanism is coupled with the steering mechanism. The illustrated device is configured for a left foot. Fig 2A shows an isometric view. Fig 2B shows a right side view. Fig 2C shows a left side view. Figs 3A to 3F show various aspects of the preferred embodiment of a steering mechanism with steering bearings contained within the perimeter of the wheel being steered. These Figs show the mechanism as it applies to a front wheel of a sporting device. Fig 3 A shows an isometric view of the steering mechanism connected to the wheel that it steers. Fig 3B shows a sectioned view of this mechanism to illustrate the interconnection of the parts. Fig 3C shows a top view with part of the wheel removed for clarity. Fig 3D shows a right side view including the relationship between the steering axis and the tire patch. Fig 3E shows a top view with the mechanism in a left turn configuration. Fig 3F shows a top view with the mechanism in a right turn configuration. Fig 3G shows an isometric view of a sporting device with the preferred mechanism configured to steer the rear wheel. Fig 4 shows an isometric view of a damping and centering force mechanism integrated with the chassis of a sporting device. Part of the chassis has been cut away to show the damper elements. Fig 5 shows an isometric view of the steering mechanism coupled with the damping and centering force mechanism and integrated with part of the chassis of a sporting device. This view shows part of the chassis cut away to show the arrangement of the internal components. Figs 6 A - 6C show an alternate embodiment of the steering mechanism coupled with an alternate embodiment of the damping and centering force mechanism. Figs 7A and 7B show views of a sporting device employing the damping mechanism as a suspension means for the chassis of the device. Fig 7 A shows the whole sporting device, and Fig 7B shows a partial view of the chassis with a cutaway to show the details of the internal damping and centering force mechanism. This figure also shows an optional restoring force means similar to the steering centering force means of Fig 5. Fig 8 illustrates a flex member steering pivot assembly useful in another embodiment of applicant's steerable wheel recreation device. DETAILED DESCRIPTION The invention will be discussed following a brief review of relevant features of certain prior art wheeled sports devices. In illustrating embodiments of the invention, certain preferred as well as several necessary mechanical components will be shown, for which common mechanical or automotive terminology is employed, with corresponding elements in different embodiments bearing the same numeral, but possibly an alphabetic suffix α.b....to distinguish among them. Among the elements appearing in the figures are a tire 10, wheel 11, damper sealing boot 12, wheel bearing assembly 13, wheel support assembly 14, kingpin 15, steering pivot assembly 16, damper housing 17, centering force mechanism 18, damper piston 19, steering link 20, chassis 21, steering axis 22, tire patch 23, fluid chamber 24, connecting pin 25, steering stop pin 26, steering lockout hole 27, steering limit track 28, suspension pivot 29, suspension link 30, and wheel rotation axis 31. A survey of the prior art demonstrates the need for a compact, lightweight, robust steering mechanism for use in sporting devices. Figs 1A to 1C show existing sporting devices that either do not have steering mechanisms or have steering systems that could be improved. Fig 1A shows a conventional roller ski. This device does not employ an explicit steering mechanism. Turns are executed by the user by lifting up one ski and putting it down again in a different direction. The direction of each of the skis must be changed consecutively, one after the other, to execute a "step turn". Such devices are widely used specifically for Nordic ski training. However, their overall use is limited due to their difficult handling characteristics. Specifically, their inability to turn gracefully or effortlessly at speed in the manner of a downhill ski makes them dangerous and difficult to use. Their use is thus limited to developing greater proficiency in a necessarily difficult muscular exercise. The situation would be greatly improved if they had a mechanism that allowed them to turn as the user transferred his or her weight. Additionally, it would be desirable to tailor the steering response to the user's input and to bumps in the environment. This is accomplished with embodiments of the present invention, described further below, which apply damping and centering forces to the wheel being steered. Fig IB shows an all terrain in-line skate of the prior art. This device also does not have an existing steering mechanism. Steering is accomplished either by step turning as described above, or by twisting the skate while the wheels are still in contact with the ground, although the latter control movement may be difficult to perform with a skate having a long wheelbase. The illustrated construction results in poor handling and can lead to crashes, especially on narrow trails where the user's feet must be kept very close together. The usefulness and enjoyment from this type of device would be greatly improved if the user could steer by leaning or changing his weight distribution at the same time as moving quickly along a narrow winding path. Fig 1C shows a prior art land surfing device. This device currently employs a weight displacement operated steering mechanism. For this type of application, the steering ability is essential to the operation of the device. The existing steering mechanism for this type of device, so far as known to the applicant, works, but it is unwieldy because it requires large frame members that extend far beyond the front of the front wheel. This arrangement also makes the device heavier and less aesthetically pleasing than if it employed a compact steering mechanism such as the steerable wheel mechanism of the present invention described below. For this type of sports device, it would also be desirable to tailor the steering response with predictable damping and centering forces. Each of the devices described above would be improved with the use of a compact, lightweight, robust weight displacement steering mechanism coupled with a damping and centering force mechanism. A list of other devices that would benefit from applicant's steering mechanisms includes, but is not limited to roller skates, ice skates, skate-skis, in-line skates, land or snow surfing devices, as well as various forms of non-sports equipment such as dollies, roller pallets and certain farm equipment or industrial machinery. The weight-steerable sporting device proposed in this patent is intended to overcome many of the disadvantages noted above. Specifically, it allows the user to traverse terrain at speed with quick alpine-ski-like turns, a trait that is especially useful on downhill sections, while still providing for various forms of locomotion on level and uphill sections. The requirement of step turning is eliminated, as is the need to twist the entire skate for executing a turn. A preferred embodiment of the present invention is shown in Figs 2A to 2C. This embodiment is in the form of a skate or ski sporting device, which is to be used in pairs, with one worn on each foot. The primary mode of use involves a motion similar to that of Nordic or Randonee skiing. Randonee skiing is similar to Nordic skiing, except that the heels of the boots have the possibility of being locked down for better control on extended downhill runs. In embodiment of Figs 2A-2C, in general, the heel of each foot is free to lift somewhat, allowing a graceful striding motion to be used to generate forward motion when on flat ground or when going up hill. One or both of the wheels may contain a one way clutch or ratchet mechanism, so that by pushing back, the wheel is made to exert a forward force to aid in forward propulsion. With the use of such a clutch, when the user strides forward, the propelling skate will not roll backward. Additionally, an outward push, or skating type motion similar to that used in ice skating, can also be used for propulsion when terrain merits. In each case, the user steers at will by leaning toward the desired turning direction. This is particularly useful once an appreciable forward speed has been attained. Steering is accomplished via a mechanism which is described in greater detail below. Preferably, the steering response is modified with an optional damping and centering force mechanism which is also described below. Additional mechanisms may be provided to disable the steering mechanism and/or to lock the user's heel down to the device for more control under certain conditions. Brakes may also be included on the device to enhance control and safety, though the brake mechanism is not specifically shown in the figures, for clarity. A sporting device configured as described above is more maneuverable and is usable on a wider range of terrain than the previously existing roller ski and skate devices. This is achieved by providing a wheel assembly that steers in response to the distribution of the user's weight. The wheel steering mechanisms of the present invention also have utility when used with devices other than the preferred sports device embodiments described herein. The following describes the steering mechanism alone so that its component parts can be understood and used in various applications. A typical embodiment of the steering mechanism of the present invention is illustrated in Figs 3A to 3G. These figures show a front wheel of a sporting device as the wheel being steered. In the figures, closely related elements have the same numerals, but different alphabetic suffixes. The present invention is designed to cause steering action based upon the user's weight displacement and lean of the device with respect to the ground. The mechanism has a wheel 11 with a hollow or dish shaped cross section. A tire 10 is mounted around the perimeter of wheel 11, which, in turn, is carried by a wheel support means 14 that includes an axle portion and a structural connection portion. Wheel 11 is rotatably mounted to wheel support 14 with a wheel bearing assembly 13. Wheel 11 is thus able to rotate with respect to the device about a wheel rotation axis 31 (Fig 3C) and allows the device to move with respect to the ground. Optionally, a one-way clutch assembly, roller clutch, or ratchet mechanism may be included as part of or next to wheel bearing 13 so that the wheel will roll forward but not backward, and a backward push on the device will result in forward propulsion. A rigid chassis 21 constitutes a fixed body or stationary assembly which all other parts move relative to. The structural connection portion of wheel support 14 is rotatably mounted to chassis 21 by a kingpin rod 15 and a steering pivot means 16. The basic operation of the steering mechanism is as follows: for the front wheel steering configuration of Figs 3A to 3F, when weight is applied to chassis 21 and chassis 21 is tilted to the side during forward motion, wheel 11 turns toward the direction of tilt. This results in steering of the sporting device. The operation of the steering mechanism described herein relies upon the steering axis 22 (Figs 3 A, 3B, and 3D), which is defined by the orientation of the steering pivot 16. Wheel 11 pivots relative to chassis 21 about the steering axis 22. Applicant defines the tire patch 23 as the contact region the where tire 10 deforms as it makes contact with the ground, as shown in Fig 3D. For the steering of a front wheel as shown in Figs 3A to 3F, the steering axis 22 is positioned just ahead of the wheel axis, and the steering axis extends rearwardly and downwardly to intersect the plane of the ground in front of the center of tire patch 23. This configuration of the axis 22 relative to the chassis 21 and the tire patch 23 ensures that the wheel turns in the desired direction when weight is applied and chassis 21 is inclined. The steering mechanism of this embodiment can utilize a wide range of bearings for both wheel bearing 13 and steering pivot 16. It also possesses a wide steering range when compared with other in-wheel steering mechanisms, an ability to accommodate a cantilevered axle, and an ability to include a steering lockout mechanism. The ability to use standard bearing types is made possible by the hollow or dish shape of wheel 11, which allows a spindle and/or wheel hub take standard bearings or bushings, yet to be positioned close to the steering axis. This advantageously reduces the cost of the device, provides a robust pivot, and allows easy replacement. The wide steering range is made possible by the fact that wheel support 14 (and the axle portion thereof) pivot with wheel 11, rather than being stationary and limiting the pivot angle as in several of the prior art examples. This wide range allows the steering to execute tighter turns than with other in-wheel steering mechanisms. The use of a cantilevered axle allows the chassis of the device to be as simple and inexpensive as a single tube or other member, such as an elongated which runs along only one side of the device. The steering lockout mechanism, described further below, is facilitated by the easy access to the parts of the steering mechanism. The user has access to a steering stop pin 26, which can be placed either in a steering limit track 28 to allow steering action, or in a steering lockout hole 27 to disable steering action by locking the steering assembly 14 in a fixed alignment. (Figs 3B, 3C and 5). While this provides one example of a simple lockout mechanism, a variety of other mechanisms are possible. Fig 3B shows that in the preferred embodiment, chassis 21 has a "yoke" feature (i.e. two arms) which extend around both sides of wheel support 14. If kingpin 15 is to be supported at both ends (either fixed or in bearings), the "yoke" feature may be incorporated into the part of chassis 21 that supports wheel support 14 as shown in Figs 3A to 3F; alternatively, wheel support 14 may have a "yoke" feature which reaches around part of chassis 21 (this configuration is not shown in the figures). The "yoke" feature may be omitted entirely if kingpin 15 is cantilevered. In that case, the chassis and the wheel support may each hold one end of the kingpin 15. Kingpin 15 may be fixed to chassis 21 so that wheel support 14 rotates with respect to it, or it may be fixed to wheel support 14 and rotate with respect to chassis 21. Alternatively, the kingpin 15 may move rotationally within its mounting in both the chassis and the wheel support. The configuration chosen depends upon strength considerations, size of the desired steering pivot, as well as the arrangement of any other damping or centering force mechanisms that may be provided, as discussed below. Fig 3G shows an embodiment of the steering mechanism configured to steer a rear wheel of a sporting device. The elements of the mechanism are the same as in the above description for front wheel steering. In addition to front only or rear only steering, it is also feasible to configure a sporting device with both front and rear wheels that steer using this type of mechanism. In the case of a steerable rear wheel, a steering axis similar to axis 22 extends downwardly and forwardly, for example, to intersect the ground behind the center of the tire patch. This condition is required for the system to be stable without an additional centering force mechanism, so that it naturally returns to a neutral steering position during forward motion when no tilt of the chassis or leaning weight is applied. In one embodiment of the invention, a damping and centering force mechanism is provided to moderate the steering movements of the steerable wheel. A preferred embodiment is shown in Fig 4, wherein a damping and centering force mechanism is mounted or incorporated into the chassis of the sporting device. Fig 5 shows a similar mechanism coupled with the steering mechanism of Figs 3A to 3G. This assembly advantageously adds biasing or centering forces to the steering system in addition to those provided by gravity and the configuration of the steering axis. The specific handling characteristics for either a front or rear wheel will in general be dependent upon the centering forces applied by the centering force mechanism in addition to the centering forces applied by virtue of gravity and the geometrical configuration of the system. Additional centering forces keep the wheel centered if it is lifted from the ground, and can modify steering behavior to suit specific terrain conditions. Centering forces can be provided through the use of springs, elastomer elements, or any other element that provides centering force when its dimensions are changed. In Figs 4 and 5, a coil spring is shown as a centering force means 18. Note that the spring 18 is attached at both ends so that it provides position-restoring centering forces when extended as well as when compressed. Applicant also contemplates the use of different spring members so that the centering forces are asymmetrical, or progressive or have an asymmetrical relationship to the angular displacement of the wheel. Such restoring force characteristics may be provided, for example, by providing an additional spring positioned within the illustrated coil spring and disposed to be compressed but not stretched, or by employing a This can compensate for any relative ease of leaning a device one way versus the other and further tailor the steering response to the user's needs. It is also desirable to add damping forces (resistance proportional to the velocity of steering movement) to the system. These moderate steering movement, preventing steering wobble, uncontrolled oscillation, and unwanted steering movement. In the preferred embodiment of the invention, damping is accomplished by coupling the steering assembly to move a damper piston 19 in a damper housing 17 when wheel 11 is rotated about steering axis 22 with respect to chassis 21. The steering and damping mechanisms are coupled by a steering link 20 which is rigidly connected to kingpin rod 15 and may be rotatably connected to piston 19. As the assembly is moved, the angle of piston 19 changes with respect to housing 17 (i.e., the piston may rock in its bore) but a good seal or fit may be maintained between piston 19 and the inner bore of housing 17 by reason of a rounded or spherical surface of the perimeter of piston 19. The housing 17 is sealed at least on one end, and possibly on both ends, defining or housing a fluid chamber 24 that forms a fluid filled volume within which the piston 19 moves. When piston 19 moves, a pressure differential is created in the fluid (which may simply be air) on either side of it. A flow-limited path is provided between areas of high and low pressure, either in the form of a small amount of clearance between the perimeter surface of piston 19 and housing 17, or by a small port through the piston 19, or a port or passage in one of the walls of housing 17. For the device shown in Figs 4 and 5 it is assumed that there is a clearance between piston 19 and housing 17 of a size to provide an appropriate resistance to motion along the axis of chamber 24, and therefore no port is shown. The limited clearance or small port causes the fluid flow to be throttled, so kinetic energy from the system is dissipated and the movement of the steered wheel is damped. Adjustments to the size of the port or to the fit between piston 19 and housing 17 change the magnitude of the damping forces generated. A damper sealing boot 12 shown in Fig 4 is a flexible membrane, preferably made of rubber, which prevents the entry of grit and debris into the housing 17. The preferred embodiment uses air damping. This advantageously a) uses part of chassis 21 as a housing for the damper system (housing 17); b) creates minimal visual clutter; c) requires few extra components; and d) adds nrinimal extra weight because of a) and c) and because air serves as a lightweight damping fluid. It should be noted however, that an effective embodiment can also be implemented using oil or another fluid as a damping medium, or using a wide variety of other damping mechanisms. The damping and centering force mechanism of the present invention can also be incorporated into a variety of devices either in conjunction with a steering mechanism, or for use with other mechamsms. Applicant also contemplates embodiments of the invention employing other steering mechanisms, or other centering and damping mechanisms. Figs 6A to 6C show an embodiment in which the steering centering force and damping mechanisms have been incorporated into wheel support 14b instead of residing in the chassis. In this embodiment, the kingpin rod 16b is rotatably connected to piston 19b via a connecting pin 25. This embodiment employs two sets of centering elastomers 18b, one on either side of piston 19b. Note that wheel support 14b has a cylindrical feature, housing 17b, which essentially serves the same purpose as housing 17 in Figs 4 and 5, and contains the piston 19b and centering elastomers 18b. Either of these embodiments of the steering mechanism can be used on various otherwise conventional wheeled recreation devices to enhance their performance with its compactness, light weight, and steering ability. It is possible to create a sporting device that uses the steering mechanism without damping and centering force mechanism, or with a different damping and centering force mechanism. If damping is not needed, piston 19 and fluid chamber 24 are not required. If centering forces are not required, centering force means 18 is not required. It is also possible to create a sporting device that uses the damping and centering force mechanism in conjunction with a different steering mechanism. It is also possible to create a sporting device that uses the damping mechanism to control a suspension mechanism or many other mechanisms. Furthermore, it is possible to create a sporting device that uses multiple damping and centering force mechanisms for different purposes within the same device. For example, a damping and centering force mechanism may also serve as a suspension assembly. Figs 7A and 7B show an embodiment of the damping and centering force mechanism arranged so that it works with a suspension mechanism for a sporting device. The device shown here is similar to the skate or roller ski devices referred to above, but it may also be adapted so that it functions as part of many other devices, such as a bicycle frame. The basic function of the suspension mechanism is to allow relative motion between parts of the chassis of the device when bumps or dips in the terrain are encountered. The result is that the forces and displacements transferred to the user are moderated. In these figures, when the suspension mechanism is operated, the two parts of chassis 21c move relative to one another, causing piston 19c to slide inside of a housing 17c. Housing 17c is part of chassis 21c, or is rigidly attached to it. This motion causes a damping effect similar to the damping effect described in conjunction with the steering mechanism of this patent. This damping effect results in improved handling characteristics when the device is used on rough terrain. The suspension mechanism shown here also incorporates a centering force means 18c similar to the centering force means for the steering described above. Centering force means 18c is attached at one end to piston 19c and at the other end to chassis 21c, so that it expands or contracts as piston 19c moves and it applies forces which urge the chassis toward a neutral or centered position. In the figures centering force means 18c is depicted as a coil spring, although many other types of centering force means can be used. In Figs 7A and 7B, the forward part of chassis 21c which comprises housing 17c is pivotally mounted to rear part of chassis 21c via a suspension pivot 29. The mechanism could also be configured so that the parts of chassis 21c slide with respect to one another rather than pivoting. A third method for performing a similar function can be arranged with the use of a four-bar linkage mechanism joining the two halves of chassis 21c. It should also be noted that piston 19c can be configured to slide in either the forward or the rear portion of chassis 21c. Additionally, a separate, pre-existing damping mechanism could be incorporated into chassis 21c rather than using the inner surface of chassis 21c as the housing for piston 19c. When the damping and centering force mechanism of the present invention is arranged to provide a suspension action, it can greatly improve the operational characteristics of the device that it is employed in. For a sporting device, specifically, the smoothness of the ride, the handling, and the range of terrain on which the device can be used will be improved. Fig 8 illustrates a flexible spring embodiment of a steering pivot assembly for mounting a wheel so that it steers by means of the rider's weight distribution. In this embodiment, a curved leaf or flex spring 31 is attached to the chassis 30 and holds the axle or bearing spindle 14 extending therefrom. The leaf spring in the illustrated embodiment curves in a generally U-shaped contour, and may also have a slight twist, such that increasing the load on the wheel causes the plane of the flex spring 31 at the axle area to move in an inward-outward sense, shifting the angular disposition of the axle 14, hence the steering direction of the wheel. The flex spring is not a true pivot, in that it may also move the axle 14 outwardly as it pivots the orientation of its axle-supporting outer end; that is, it shifts the axle 14 outwardly as it flexes, thus introducing additional translational movement. However this does not impair the desired steering effect. Furthermore, in this embodiment, the flex spring 31 may provide the steering pivot mechanism, a softened suspension, and an automatic centering effect to return the steering to a neutral position when loading is reduced. The flex suspension with weight distribution steering need not be restricted to flexures with a curved spring plate as shown, but may also be implemented with a central body of flexible material, such as a rubber block, in which separate axle-holding and chassis- attaching structural or connecting plates are embedded in respective orientations effective when they flex to achieve the desired deflection of the steering direction as the weight loading on the axle varies. As noted above, the wheeled recreational device of the present invention may include a braking mechamsm. One presently preferred implementation of such a mechanism is a disk brake having a rotor at one or more of the wheel assemblies, and preferably actuated by a mechanism such as a cable which attaches to the cuff of the user's boot and exerts tension as the lower leg angles forward. This mechamsm allows the rider to crouch down, into a stable position with flexed knees suitable for stopping, and thus initiate braking action as he assumes this posture. The actuating cable may in turn connect to a hydraulic cylinder, or to a mechanical camming linkage for moving the brake friction material, e.g., shoes or pads. Figs 2A to 2C, 3G, and 7A show skate / ski devices which employ a chassis structure that runs along one side of the foot and wheels, rather than under the foot and around both sides of the wheels as in most of the prior art devices. The configuration of WO 00/27488 PCT/TJS99/2613t> running a structural member along the side of the foot is advantageous for the following reasons: a) It allows the use of a single tube or other member for simplicity; b) It facilitates making the device lightweight; c) It similarly allows the manufacturing to be economical; d) It allows the maximum possible ground clearance when bumps and debris are encountered; and e) It facilitates the use of mechanisms including, but not limited to the in-frame damping and centering force mechanism of this patent. Thus the reader will see that the steering mechamsm of the invention can be used to greatly improve the maneuverability and handling characteristics of a device, particularly a skate or roller ski. The use of the damping and centering force mechanism of the invention, either in conjunction with a steering mechanism, or a suspension mechanism can further enhance the performance of such a device. Additionally, such a device can be manufactured simply and inexpensively with the use of the one-sided chassis of this invention. While the above description describes the specific illustrated embodiments, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of preferred embodiments thereof. Many other variations are possible. For example, in addition to a one piece flexible member or flexure, a hinge could be used for the steering pivot, rather than the embodiments shown in the figures; other linkages could be used to facilitate suspension action while still using the damping and centering force mechamsm of the invention, and the one-sided frame could support the front wheel from the left side and the rear wheel from the right side, or vise-versa, while still passing by the foot substantially to one side as provided in the invention. Accordingly, the scope of the invention should be deteπriined not by the embodiments illustrated, but by the appended claims and their legal equivalents. What is claimed is:

Claims: CLAIMS 1. A recreational wheel device of the type having a chassis for supporting the user and having a wheel assembly mounted to the chassis, wherein the wheel assembly includes a steerable wheel having an outer radius and a rotation axis a wheel bearing having a bearing radius and mounted for rotation of said steerable wheel about said rotation axis a steering pivot substantially disposed within the outer radius of said steerable wheel and extending radially beyond said bearing radius of the wheel bearing and a wheel support assembly structurally carrying the wheel bearing, said wheel support assembly being mounted to pivot on the steering pivot such that the steerable wheel responds to weight distribution of a rider supported on the chassis whereby the recreational device is actively steered through the rider's weight displacement. 2. The recreational device of claim 1, wherein said device is selected from among a skate, a skateboard and an in-line ski. 3. The recreational device of claim 1 , wherein said wheel assembly further comprises a fixed non-steerable wheel. 4. The recreational device of claim 3, wherein said steerable wheel is cantilevered from said chassis. 5. The recreational device of claim 4, wherein said chassis extends along one side of a users foot. 6. The recreational device of claim 1, further comprising a damping assembly for modulating movement of the wheel support as said steerable wheel steers. 7. The recreational device of claim 6, wherein said damping assembly resides within and is protected by the chassis. 8. The recreational device of claim 1, wherein said steering pivot comprises a kingpin aligned proximate the plane of rotation of said wheel. 9. The recreational device of claim 1, further comprising means for limiting rotation of said wheel to one direction thereby allowing the user to propel the device by pushing. 10. The recreational device of claim 1, wherein the steering pivot pivots about a pivot axis that intersects the ground at a center line of said wheel. 11. The recreational device of claim 1 , wherein said wheel includes a tire having a construction selected from among pneumatic tires, solid tires made of resilient material, and tires filled with a foam material. 12. The recreational device of claim 1, further comprising a brake assembly. 13. The recreational device of claim 1, further comprising a centering assembly for exerting restoring force to center the steerable wheel. 14. The recreational device of claim 1, further comprising locking means for locking said steerable wheel in a fixed alignment. 15. A recreational device having a plurality of wheels and including a steerable wheel having an outer surface and a rotation axis a wheel bearing mounting said steerable wheel for rotation about the rotation axis a steering pivot assembly defining a steering pivot axis, and a wheel support mounted to said steering pivot assembly and carrying said wheel bearing so that the steerable wheel is steered as the wheel support moves about the steering pivot axis, wherein the wheel support is mounted substantially within the contour of said wheel such that the pivot axis lies close to the center plane of the steerable wheel and weight distribution applied by a user standing on the device is effective to move the steering pivot assembly and steer the device via said steering wheel. 16. A chassis for a foot mounted sporting device such as an in-line skate or roller ski, such chassis comprising a) a structural member extending from front to back so as to define a wheelbase, and b) a damping system substantially contained within said structural member for moderating handling behavior, such as the steering and suspension, and which includes i) a damper housing, ii) a damper piston, and iii) a fluid chamber, whereby a device incorporating said chassis exhibits improved handling behavior. 17. The chassis of claim 16, wherein said damper housing is an integral part of said structural member, whereby said chassis can be of lightest possible weight and lowest possible cost and complexity. 18. The chassis of claim 16, wherein said damper housing is rigidly attached inside said structural member, whereby an existing damping system can be incorporated into said chassis to reduce manufacturing cost. 19. The chassis of claim 16, wherein said fluid chamber is filled with air, and optionally wherein an outer surface of said piston is rounded so the piston may rock within said damper housing while sealing thereagainst. 20. A chassis for a foot mounted sporting device such as an in-line skate or roller ski, such chassis comprising a) a structural member, and b) a centering force system substantially contained within said structural member to moderate handling behavior, such as steering or suspension, said centering force system including one or more elements of the group of elements consisting of metal springs, rubber springs, rubber bumpers and elastomeric bodies, whereby a device incorporating said chassis exhibits a self-centering handling behavior. 21. The chassis of claim 16, further comprising a centering force system to moderate handling behavior, for example including but not limited to steering and suspension, and which is substantially contained within said structural member, and which comprises one or more elements selected from the group consisting of metal springs, rubber springs, rubber bumpers and elastomer bodies, whereby a device inco orating said chassis exhibits an improved handling movement that is both controllably damped and self centering. 22. The recreational device of claim 1 configured as a skate or roller ski, and wherein the chassis includes a structural member, said device further comprising a) a damping system substantially contained within said structural member which can be used to moderate handling behavior, for example including but not limited to steering and suspension, and which includes i) a damper housing, ii) a damper piston, and iii) a fluid chamber, and b) a restoring force system to moderate handling behavior such as steering or suspension, and which is substantially contained within said structural member, said restoring force system including one or more elements selected from the group consisting of metal springs, rubber springs, rubber bumpers and elastomer elements. 23. A sporting device to be used in pairs with one on each foot, for example an in-line skate, roller ski, or roller skate comprising a) two or more wheels, and b) a chassis with primary structural or load bearing portion thereof disposed substantially to either the left or the right side of the user's foot, whereby said sporting device can be economically constructed, for example using a single tubular member or molded part for the structure of said chassis, and said sporting device can have as much clearance over rough ground, curbs, and other objects as possible. 24. The sporting device of claim 23, wherein the structural or load bearing portion of said chassis is in the form of one or more tubular members. 25. The sporting device of claim 23, wherein the structural or load bearing portion of said chassis is in the form of one or more members selected from a group consisting of tubular members, channel members, molded composite members such as carbon fiber members, and molded plastic members. 26. The recreational device of claim 1, configured for the device to be used in pairs with one on each foot, for example as an in-line skate, roller ski, roller skate or the like, and wherein the chassis includes a primary structural or load bearing portion thereof disposed substantially to one side, e.g. either to the left or the right, of the user's foot, and carries the steering pivot of the steerable wheel assembly, and further incuding a damping system substantially contained within said structural portion of the chassis and which connects to the wheel support assembly to moderate steering motion of said wheel and wheel support, and which includes i) a damper housing, ii) a damper piston, and iii) a fluid chamber, and a restoring force system to moderate steering behavior connecting to said damper piston, which is substantially contained within said structural member, and which comprises one or more elements selected from the group consisting of metal springs, rubber springs, rubber bumpers and elastomer elements, whereby a sporting device with a lightweight, economically constructed chassis is steerable by weight displacement or inclination with respect to the ground while effectively exhibiting a damped self centering steering response.

Inventors: PAGE JAMES S, PAGE, JAMES, S.
Applicants: CROSSKATE LLC, PAGE JAMES S, CROSSKATE, LLC, PAGE, JAMES, S.
Application year: 1999
Main classification: A63C5
IPC codes: A63C5, A63C17