US20020070514A1

US20020070514A1 - Omnidirectional spherical roller caster

Info

Publication number: US20020070514A1
Application number: US09/735,690
Authority: US
Inventors: Ronald Costa; Dale Rorabaugh
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-12-12
Filing date: 2000-12-12
Publication date: 2002-06-13

Abstract

A caster capable of omnidirectional transport having a spherical roller freely mounted within a housing having a concave spherical cavity. A plurality of cylindrical bores is disposed perpendicular to the inner concave surface in equilateral geometric configuration, axially converging toward the center of the cavity. A plurality of small internal caster assemblies, mounted for free independent rotation about the convergent axis, extend from within the bores to contact the spherical roller, thereby creating a loading surface capable of providing omnidirectional rotation. The spherical roller interfaces between the loading surface of the cavity and a surface onto which the entire caster assembly is imparted omnidirectional movement.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to caster/roller systems, and is more particularly is directed toward a new and improved spherical roller caster system advantageous for omnidirectional movement over and against surfaces.

2. Description of Related Art

2.1 Casters and Rollers

Casters are very ancient, and rollers even more so, possibly even preceding the wheel. Rollers support unidirectional rolling movement. Casters support ominidirectional rolling movement, but at a price. Once aligned in the desired direction of movement, a caster presents but little rolling resistance, and essentially serves as a roller or wheel. However, if a caster is not properly aligned for rolling movement in a new direction then the caster must “swing around” its pivot axis until the correct rolling alignment is assumed. This swinging motion involves a slipping and a sliding, as opposed to a rolling, of the wheel of the caster. This swinging motion is typically at a much greater frictional loss than rolling, thus causing loss of energy. If a load supported by the caster is at rest, inertial and frictional resistance must be overcome before the caster assumes proper alignment for subsequent rolling support, and movement, of the load. This resistance can cause jerky, spasmodic, imprecise, and energy intensive initial motion of the load. In other words, it is hard to get a stationary heavy load supported on casters initially improperly aligned to the desired direction of movement to commence movement in the desired direction, let alone to smoothly do so. It would accordingly be of value if a caster could be developed that, while retaining the low rolling resistance of a true caster, was in all respects ominidirectional, with absolutely no preference as to direction or initial direction in the motion of a supported load.

A previous partial solution to this problem of a true omnidirectional caster is the spherical ball roller. Insofar as supported in typically lubricated hemispherical cavities, a spherical ball caster will have no directional preference in its rotation that is supportive of a rolling movement. However, the exposed rolling surface of the sphere may pick up such contamination from the surfaces, normally a floor, over and on which rolling is performed as does, when later rolled into the supportive cavity, cause increased frictional resistance. The clear answer to supporting a hard spherical ball caster for omnidirectional rotation is to support the spherical ball itself on a space frame of arrayed secondary rollers or casters, normally three such secondary rollers. The problem is that such a structure simply moves the frictional scrubbing an misalignment problem to another, lower, level, dictating that even the spherical ball roller caster will at least initially present a higher rolling resistance in some directions than in others.

2.1 Dry-Ground Roller Skates

Referral to roller skates herein is so as to relate the evolution of roller- and caster-based mechanical support for unrestricted omnidirectional motion, particularly as desired in the sports field. This somewhat systematic evolvement is germane, as well, to general improvement of mechanical support for spatial mobility, whether in sports-related or industrial applications.

The thrill of snow sports has captured a large market. Unfortunately, the predominant part of world has no snow, or has long periods without snow. Especially in this age of visual communication, the grace and beauty of ice figure skating, and the sheer excitement of snow skiing and snowboarding has attracted the masses in snowless areas. In-line roller skating is currently very popular because it provides skaters the opportunity to skate without the need for ice. Common paired-wheel roller skates, known and manufactured for many years, can move either forward or backward only in a straight line, but these roller skates cannot rotate and spin like figure skates. Additionally, because of this wheel arrangement, it is difficult for a roller skater to lean left or right, in order to pivot or negotiate tight curves. Conventional in-line skates having single in-line wheels simulate the feel and motion of ice skating, but do not achieve the apparently free movement of figure ice skates.

The following patents illustrate the desire and development of unusual or modified wheel arrangements on dry-land skates. U.S. Pat. No. 301,676 issued to Clark in 1884 describes a roller skate with a double bracket having rollers mounted on independent shafts. U.S. Pat. No. 954,993 to Peters in 1910, describes a roller skate having a plurality of pairs of rollers and a plurality of single rollers, the pairs of rollers and single rollers being disposed alternately in curvilinear arrangement. The peripheries of the single rollers being disposed within those of the pairs of rollers. A continuous bearing surface is thereby presented for the entire skate.

Generally, wheels mounted on a single axis can only turn in one plane. The skates with wheels set at the periphery are limited to forward and lateral motion only. Combining the two does not result in resistance-free omnidirectional motion.

The versatility of roller skates was improved with the introduction of roller blades. These skates have a single line of round wheels; imitating the blade of an ice skate, and pivoting sideways is achievable. However, because the wheels are mounted on horizontal shafts, the roller blades cannot rotate and spin like ice skates. Figure skates themselves cannot glide sideways in any direction from the axis of the blade.

U.S. Pat. No. 5,566,958, 1996, issued to Sinelnikov, et al, describes an in-line roller skate having a side motion wheel support and a plurality of side wheels rotatably connected to the support, arranged at approximately right angles to the skating wheels, arranged such that when upright on a flat surface, the vertical skating wheels contact the flat surface and the side wheels do not. But, when the roller skate is tilted beyond a set angle from vertical, the side wheels contact the skating surface.

U.S. Pat. No. 5,295,701 issued to Reiber in 1994, describes a roller skate assembly that includes longitudinally aligned front and rear rollers, and a center roller which is mounted between the front and rear rollers. The center roller is alternately positionable in a longitudinally aligned or a transversely offset position relative to the in-line rollers. Other related art patents for wheels rotating about a single axis include U.S. Pat. Nos. 2,445,268 to Hodgins; 3,072,169 to Hastings; 3,170,235 to Williams; 3,757,383 to Iiyoshi; 3,789,947 to Blumrich; 3,936,061 to Wada; 4,054,335 to Timmer (showing a caster wheel); 4,058,324 to Dallaire (describing an early version of an in-line skate with maneuverability adjustments) and 4,070,065 to Heitfield (describing a wheel for skateboards and roller skates); 5,246,238 to Brown (showing a single axis roller skate wheel with a plurality of further single axis bearings along its periphery, which rollers rotate perpendicular to the plane of the wheel, so that the skate can move in the forward and lateral directions—laterally only for braking purposes). U.S. Pat. No. 5,382,031 to Marconato describes a roller blade skate with single axis wheels that can also slide sideways. U.S. Pat. No. 5,388,623 to Homma describes elastic single axis wheels. U.S. Pat. No. 4,090,283 to Woolley describes a method of making a hollow globular roller rotating about a single axis.

Skates employing spherical rollers in lieu of cylindrical rollers, or wheels, as the primary rolling elements have used either simple sockets or ball bearings to support larger spherical rollers. These combinations are not desired from the standpoint of too much friction or too little control.

U.S. Pat. No. 4,076,263, to Rand, 1978, describes a ball skate having a configuration which intentionally does not allow lateral motion. U.S. Pat. 5,716,074 to Theodorou, 1998, finally described a multi-directional in-line roller skate having spherical roller wheels with multi-directional turning ability. The skate includes a single line of spherical rollers, which substitute for the single axis wheels of a common roller skate, but can roll sideways. The configuration of this skate mechanism is very complex and cumbersome, costly to manufacture and repair, and control in other applications is doubtful.

2.3 Skateboards

The basic configuration of skateboards has been, to date, deck, trucks, and wheels. While advances such as urethane wheels, kicktails, laminated wood decks, precision bearings, griptape and concave decks have offered better control, they have not changed the motion characteristics, relying instead on straining riders' athletic ability to squeeze new performance limits from existing equipment.

Snowboarding is a sport rapidly growing in popularity, initiated by the freedoms of movement afforded by snowboards. A snowboarder uses the presence of sidecut and flex to turn by leaning, referred to as “carving,” towards the intended direction of travel and involving little or no lateral slippage. The radius of turn is controlled by adjusting the weight applied. Additionally, a snowboard has the ability to slide virtually in any direction, or combination thereof

Until U.S. Pat. No. 5,833,252, to Strand, 1998, this omnidirectional travel on dry ground has not been achieved. To that date, expert riders employed a technique called “powersliding”, wherein, through brute force, a skateboard was driven sideways. This is a very difficult and dangerous maneuver, requiring high speed-generated momentum to overcome friction of the wheels as the riders pushed their boards far out in front of their bodies, necessitating the use of heavily padded gloves to protect their hands while leaning and dragging on the passing pavement. Because powersliding requires the rider to travel fully sideways, the subtle moves available on a snowboard are virtually unachievable.

The variety of maneuvers made possible by these omnidirectional movements presents a kind of trill of motion heretofore unavailable. Transitioning, in a highly controlled manner, in and out of skidding in any direction and carving while in motion down a hill, a snowboarder can rotate at any angle, land a jump in any orientation. Naturally, the great appeal of snow sports has led to attempts to replicate the thrills on a dry surface. U.S. Pat. Nos. 4,134,598 to Urisaka, 1979; 4,805,936 to Krantz 1989; 5,195,781 to Osawa, 1993; 4,744,576 to Scollan, 1988 represent these attempts with respect to skiing, and 5,259,632 to Mahoney, describing a skateboard adapted for use on ice with rotating thin cylindrical blades. None of these are examples of true omnidirectional movement on dry land.

Of related art examples proffering true lateral motion, U.S. Pat. No. 5,312,258 to Giorgio, 1994, uses an array of ball-type roller bearings on a constructed half pipe, however, his device does not include means for controlling the omnidirectional motion. U.S. Pat. No. 3,827,706 to Milliman, 1974, uses a combination of pivoting casters and fixed wheels, the casters disposed slightly closer to the ground than the fixed wheels, allowing a skier to angle the ski in and out of a sliding mode; however, no means is provided to stabilize the casters or to smooth the transitions as weight is transferred from a pivoting caster to a fixed caster. U.S. Pat. No. 4,886,298 to Shols, 1989, employs a complex twisting ski design that combines four casters with normal skateboard trucks.

Four patents use a biased, pivoting caster. U.S. Pat. Nos. 4,460,187 to Shimizu, 1984, describes two skis and 5,125,687 to Hwang, 1992, describes a board for simulating the parallel skiing body position. Both inventions have a single front caster with a spring tensioning the caster to point straight ahead. These inventions neither permit lateral sliding or the caster to rotate through 180 or 360 degrees nor multiple bias on the caster. Shols, 1989, describes a bias by a hinge means and a compliant mounting surface; however, this configuration does not permit more than one direction of bias, allows wobbling and does little to help the rider get back into the straight-ahead position.

Finally, in U.S. Pat. No. 5,833,252, 1998, Strand describes a lateral-sliding roller board that allows a rider lateral sliding motion somewhat similar, but far from equivalent, to a snowboard. The roller board has a platform with four fixed wheels and two pivoting rollers along the platform's longitudinal axis. The fixed wheels function similarly to conventional skateboard trucks, while the pivoting rollers are spring-biased to align them with the longitudinal axis of the platform allow them to rotate in alignment with the direction of force exerted on the platform. Transfer of weight from one type of roller to the other is facilitated by a height differential between the two types of rollers.

2.4 Other Transport Machines

Biased casters that allow unimpeded 360 degree rotation and specific force profiles are described by U.S. Pat. Nos. 4,246,677 to Downing and Williams, 1981, and 4,280,246 to Christensen, 1981. These inventions relate to semi-automated cart delivery systems typically used in hospitals for transporting food and medication. When the carts are lifted, the pivoting casters rotate to a preset angle, allowing them to move through an automated system. When the casters are touching the ground, the inventions function only to lessen wheel flutter. They are not intended to augment the cart's motion and steering characteristics. U.S. Pat. No. 4,715,460 to Smith, 1987, shows a wheelchair base with single-axis wheels having bearings in the circumferential periphery thereof The bearings rotate perpendicularly to the plane of each wheel, so that the wheels can move laterally. However, the wheels are limited to forward and lateral movement at a direction roughly perpendicular to the forward movement, but not at any angular movement at angles between 0 and 90 degrees off from the forward direction.

Many types of omnidirectional vehicles are known in the art. For example, La, in U.S. Pat. No. 4,237,990, describes an omnidirectional bumper car for amusement parks. Ziegler in U.S. Pat. No. 3,295,700 describes an omnidirectional vehicle for use in handling radioactive materials. Suitable wheels for such vehicles are described in U.S. Pat. Nos. 3,789,947 to Blumrich and 3,876,255 to Ilon. The omnidirectional nature of the vehicle made provision of other suspension systems difficult. In addition, the cumbersome design of these prior art omnidirectional vehicles rendered them inapplicable to skates skateboards, wheelchairs, omnidirectional conveyor platforms, and the like, in which all of the propulsion, suspension, and control must be situated in a relatively small area beneath the user or seat of a chair.

All of the single axis wheels can only rotate in one plane, except for the complicated devices with further, complicated single bearings built into the circumference of the larger single axis wheel. These arragements result in “scuffing,” which creates considerable friction and load on the wheels. Furthermore, upon information and belief, no other caster system has an independent, free-mounted spherical roller with control features in a very simple design, thereby providing movement effectively, smoothly and easily in any angular or rotating direction.

Therefore, there is a need for a spherical roller caster system of simple design, simple maintenance, inexpensive to build and repair, and hitherto unobtainable omnidirectional movement.

SUMMARY OF THE INVENTION

The present invention contemplates a new and improved spherical roller caster system that is substantially continuously totally without directional bias in support of omnidirectional movement in any direction over and against surfaces, such as on streets, sidewalks, floors and similar surfaces, and conversely movement of surfaces over the caster, as for example, a roller platform appending a conveyor. The present invention also relates to sport vehicles that can transition in and out of a mode of controlled omnidirectional motion.

To be “without directional bias” means that the rolling resistance of the roller is, both initially in the movement of a load and at all subsequent times, substantially identical no matter in what initial, or subsequent, direction or directions the load should be moved. A load supported on the new spherical roller caster system may, for example, be initially equally easily moved in any direction of the compass, and may thereafter trace a serpentine path, without experiencing (normal inertial forces excepted) that it is at any time any less smooth or more difficult to move the load in any direction. The closest analogy to the type of motion supported is in the support of a load, such as a puck, upon an air bed, such as a game table, where the jets of supporting air clearly do not bias the load (the puck) to any predetermined direction of motion.

Accordingly, the principal objective of the present invention is to bring a heretofore-unrealized freedom of movement to a caster to render it capable of omnidirectional movement, which can be used in multitudinous applications with minor configurational adjustments of this invention. In this regard, the object of the present invention to provide spherical roller casters that are easy to control and function in a far more unrestricted, but controlled manner.

Another object of this invention is to provide transport systems of simple, low-cost construction capable of this free-form, but controllable action.

Yet another important object of the present invention is to bring an unrestricted freedom of movement in sport, as best exemplified by snowboarding, to skateboarding over warm, dry surfaces, without the necessity of snow or of waiting for appropriate seasons to practice this free movement.

Further objects relative to the skateboard are: to provide the ability to turn rapidly, or “carve,” when leaning to one side, to provide the ability to instantly shift into a mode of omnidirectional behavior, easily travelling forwards, backwards, sideways or various combinations thereof, to provide the ability to transition smoothly and controllably between carving and the omnidirectional mode, to provide a skater an interface between his board and the surface on which he rides that imitates characteristics of a snowboard, where the omnidirectional mode is engaged when weight is relatively evenly distributed across the board and exited by transferring weight to the board's edge, to provide the ability to perform partial or complete rotation, repeatedly, while skateboarding, without lifting, while in motion, to provide the ability to ride on different types of terrain, including paved surfaces, tile and wood floor, ice, fabric and dirt by making simple adjustments. Such a device must be economical to produce and sell, so that anyone may enjoy its advantages.

Still yet another object of the present invention to bring a new freedom of movement to casters in industrial and domestic use.

1. A Caster Supporting Omnidirectional Transport

Accordingly, in one of its aspects, the present invention is embodied in a caster supporting omnidirectional transport. The caster includes a sphere supported within and by a space frame, or housing. The housing defines (i) an imaginary hemispherical cavity, having a radius between its pole point and center, juxtaposed relative to substantially half the sphere, and (ii) at least three imaginary bores in substantially equilateral geometrical configuration, and substantially equidistantly arrayed about the cavity's pole point, within the imaginary hemispherical cavity. Each imaginary bore has an axis that both converges towards the center of the sphere and that is at an acute angle to the radius of the imaginary hemispherical cavity. This accute angle is less than 90 degrees, and is more preferably 60 degrees or less.

Within each bore there is an assembly extending to contact the surface of the sphere. Each assembly has an annular bearing mounted to the housing centrally about the axis of the bore for free independent rotation about the axis of the bore. There is (i) a shaft mounted internally within the annular bearing at a position that is offset from the axis of the bore, and (ii) a wheel rotatably supported by the shaft and contacting the sphere for the support thereof

Thus, the sphere is ultimately supported on an by (i) the collective shaft-mounted mounted wheels of (ii) the collective shafts of (iii) the collective annular bearings of (iv) the collective caster assemblies as are supported in (v) the collective bores of the space frame, or housing. This support creates a loading surface permitting omnidirectional rotation of the contacted sphere.

Importantly to the caster's support of omnidirectional movement, the offset of each shaft and of the wheel that is supported by that shaft from the converging axis of the associated imaginary bore makes that such force moment as is developed upon changing rotational direction of the sphere causes may cause rotation of the annular bearing of one or more of the assemblies. It is (i) this offset, and (ii) this rotation, in the support of the rotating sphere of the caster that facilitates that any all changes in rotational direction transpire smoothly, and without any appreciable differentiation. The caster is truly omnidirectional. The sphere or spherical roller can be contained and supported within the housing by a removable annular retainer. Thus, the containing and supporting is comprised of a set of small caster assemblies providing load-bearing interfaces between the concave regions outlining the spherical cavity and the spherical rollers, thereby providing multidirectional movement capability. Also contemplated is a self-lubricating annular lip on the retainer surface circumscribing the opening and disposed within a plane distal from the equator of the roller.

In one preferred embodiment, the annular outer surface of the bearing assembly of the internal caster has splines and is press-fitted into a splined bore, thereby retaining the caster within the bore. There are, of course, many other means of fitting the internal caster assembly known to those familiar with the art. The interior of the housing can be exposed for cleaning and servicing of assemblies therein by removing the annular retainer fastened to the housing.

The spherical roller of the caster of may be comprised of a homogeneous material, with a texture and resiliency depending on the need for durability, friction or softness. Or, it may alternatively be comprised of a heterogeneous material, such as a hard core with a resilient surface.

2. Use of the Omnidirectional Caster In a Skateboard

In another of its aspects, the present invention is embodied in an omnidirectional skateboard. Such a skateboard has an integral, elongated, structurally rigid, single-piece platform for supporting a user. The platform has a flat central portion with a longitudinal axis, bilateral upwardly inclining wings extending from the central portion, and fore and aft upwardly-angled extensions.

There is at least one spherical roller assembly (caster) as defined in section 1 above that is longitudinally spaced and centrally attached to the underside of the flat central portion of the platform. Each such assembly has a housing with at least one downwardly open spherical cavity. The cavity is defined by at least three shallow cylindrical bores in the inner, upper surface of the housing defining the spherical cavity. The bores are positioned to form an equilateral geometrical configuration with the axis of each bore aligned to the center nucleus of the spherical roller, as defined hereinabove. There is a plurality of small internal caster assemblies fitted within these bores, extending in a spherical geometrical relationship axially aligned to the center of the cavity. Each small caster assembly has an annular bearing assembly, having an inner void space and a splined exterior surface. There is a shaft transversely mounted within, and offset from, the center of the void space. The longitudinal axis of the shaft is transverse to the rotation of the bearing assembly. The shaft supports a wheel, thereby creating a loading surface capable of providing omnidirectional rotation when in contact with a surface.

A spherical roller, freely mounted within the spherical cavity of the housing, rollably communicates with the wheel, thereby interfacing between the loading surface of the spherical cavity and a surface onto which the roller apparatus (caster) is imparted omnidirectional movement. The spherical roller is contained within the housing by a retainer, such that a portion of the spherical roller protrudes from the housing, thereby allowing contact between the spherical roller and the surface over which it travels. The internal parts of the caster are repaired and cleaned by removing the removable retainer.

Alongside the omnidirectional caster(s), is a plurality of equally spaced, longitudinally aligned fixed-wheel assemblies attached to the underside of each of the upwardly inclined wings of the platform structure. Each fixed wheel assembly is mounted on a shaft fixedly oriented transversely to the central longitudinal axis of the platform, and configured to maintain the fixed-wheels mounted thereon in axial alignment relative to the platform structure.

Another preferred embodiment contemplated by this invention is a conveyor platform that permits omnidirectional movement of matter over its surface. It has an integral, dimensional, structurally rigid, platform and one or more attached housings, having one or more concave spherical cavities, each having an annular opening to the exterior of the housing. There is also a plurality of cylindrical bores equilaterally disposed on the inner surface of the housing opposite to the annular opening, each bore aligned to the center of the cavity, a spherical roller, and a proportionately small internal caster assembly fitted into each cylindrical bore. The caster assembly contains an annular bearing fitted within the bore, a shaft rotatably mounted within a void space defined by the annular bearing, with a longitudinal axis of rotation transverse to the axis of rotation of the bearing, and a wheel rotatably supported by the shaft for rollably interfacing between the inner surface of the cavity and the spherical roller, thereby providing a loading surface.

The spherical roller concomitantly rollably interfaces between the bearing assemblies and a surface with which the spherical roller communicates, allowing omnidirectional movement. There is means for retaining the spherical roller within the housing, such that a portion of the spherical roller protrudes from the housing, thereby allowing contact between the spherical roller and a surface. There is also means to open and close the housing, for performing repairs and cleaning the contents thereof.

The platform may have a plurality of internal caster assemblies disposed in equilateral geometric configurations about the spherical rollers, forming load-supporting surfaces axially aligned to the spherical roller center nucleus. This configuration is capable of imparting uninfluenced omnidirectional rotation to the spherical roller.

The spherical roller may be retained within the housing by a removable annular retainer, whereby only a portion of the spherical roller extends beyond the annular retainer. The internal caster assembly may have splines on the annular bearing surface, which is press-fitted into a splined bore. There may be means to access the housing and assemblies therein for cleaning and servicing by removal of the removable retainer.

The spherical roller may be comprised of a homogeneous material depending on the nature of the surface contacted and therefore the requirement for durability, friction or softness, or of a heterogeneous composition, having a hardened core with a resilient surface.

Further objects and advantages of this invention will become apparent from a consideration of the drawings and ensuing description. Notwithstanding the prior art, the present invention is neither taught nor rendered obvious thereby.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can best be understood in conjunction with the accompanying drawings, in which: [0055]
FIG. 1 is a perspective top view of a spherical roller caster assembly of the present invention showing the spatial arrangement of the component parts; [0056]
FIG. 2 is a perspective bottom view of the roller assembly with the spherical roller removed, showing the concave spherical cavity and embedded small casters that form the loading surface for the spherical roller; [0057]
FIG. 3 is a perspective bottom view of an alternate embodiment of roller assembly of the present invention, showing a different set of ball-like wheels within the small casters; [0058]
FIG. 4 is a cross sectional side elevation of a small caster assembly that is part of the loading surface for the spherical roller of this invention. This view is of an upside-down caster, as in a conveyor platform; [0059]
FIG. 5 is a bottom perspective view of the roller skateboard (“Omniboard”) of the present invention, showing a single central spherical roller caster flanked by rows of conventional in-line skate wheels; [0060]
FIG. 6 is a bottom perspective view of an alternate embodiment of the roller board of the present invention, showing two central casters in tandem; [0061]
FIG. 7 is a close-up front cross-sectional view of a roller board just in front of the single central caster in FIG. 5; [0062]
FIG. 8 is a close-up front view of the roller skateboard of FIG. 7, banked to the right; [0063]
FIG. 9 is a top view of a conveyor platform employing a plurality of the rollers of this invention. The caster surface of the platform can be a grid of single units as shown, or any size housing(s) having a plurality of cavities containing casters of this invention; [0064]
FIG. 10 is a cross-sectional cutaway side elevation of the load-bearing small caster assembly that communicates with the spherical roller of this invention as an alternate embodiment of that in FIG. 4, having a compression bearing; [0065]
FIG. 11 is a schematic cross-sectional side elevation of an alternate embodiment of this invention, showing a screw-in type of caster; and [0066]
FIG. 12 is a perspective side view of another alternate embodiment of the instant invention, showing a scalloped, largely open housing.[0067]

5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A. EXAMPLE ONE

OMNIDIRECTIONAL CASTER

Below is a detailed general description one preferred embodiment of a spherical caster defined by this invention that is capable of omnidirectional movement, said caster having a multitude of useful applications. Such a generalpurpose caster can be manufactured in a variety of sizes, and from a variety of materials known to those who practice the art. The description below is an example of a preferred embodiment, and is not intended to limit the invention to that described, or depicted. [0068]
Referring now to FIGS. 1, 2 and [0069] 3, this apparatus comprises a housing 10, containing at least one spherical cavity (FIG. 2, 12), the cavity defining a directionally open 2 spherical socket designed to hold a spherical roller 9. The cavity 12 has a plurality of shallow cylindrical bores 4 in its concave spherical surface opposing the annular opening 2. The bores 4 are positioned to form an equilateral geometrical configuration (an equilateral triangle, as an example, is indicated by the stippled line in FIG. 1, and three is the minimum plurality required). There is also a plurality of small circular “swivel” wheel/bearing assemblies (small casters), as shown in FIGS. 4 and 10, one to fit within each bore 4, extending in a spherical, geometrically ordered relationship in contact with the spherical roller 9 (also FIG. 11,9).
Referring now to FIG. 4, each swivel assembly has annular ball bearings [0070] 46, seated within a race 47, mounted for free independent rotation within one of the cylindrical bores in the upper surface of the spherical socket. Each annular bearing has a shaft 40 mounted within its annular void space, the longitudinal axis of which is transverse to the rotation of the bearing 45. Each shaft rotatably supports a load-bearing wheel 42 (or wheel/bearing 41/42) communicating with the spherical roller that is freely mounted within the socket, thereby creating a loading surface capable of providing omnidirectional rotation when in contact with the spherical roller.
As seen in FIG. 11, the spherical roller, [0071] 9 rollably interfaces between the swivel-type loading surface of the socket and a surface (such as a floor) onto which the spherical roller is imparted omnidirectional movement. The spherical roller 9 is contained within the housing 114 by a removable ring 118 (see also FIG. 3, 16), such that a portion of the spherical roller protrudes from the housing, thereby allowing contact between the spherical roller and the traveled surface. The ring can be removed for opening the housing to permit repairs and cleaning of the omnidirectional roller apparatus.
In one preferred embodiment of this invention, the plurality of swivel assemblies comprises three, configured in the form of an equilateral triangle (FIG. 1, stippled line) immediately above the [0072] spherical roller 9, forming a load-supporting triad capable of imparting omnidirectional rotation to the spherical roller. This load-supporting triad has an upper set of three swivel assemblies (casters) providing load-bearing interfaces between the concave region (FIG. 2, 12) and the spherical roller (FIG. 1, 9), and for providing multidirectional movement capability. It also has a lower retaining plate 16 (FIG. 2, 3; see also FIG. 11, 114) placed within a plane below the equator of the spherical roller 9. The retaining plate (or ring) has a self-lubricating annular lip FIG. 3, 14 on the upper surface circumscribing the annular opening. A Teflon insert or screw as shown in Figure can also provide the lubrication 12, 137, or any means known to those who practice the art. The swivel assemblies may have splines and be press-fitted into each of the triad of splined shallow cylinder bores 4. The housing cavity 12 can be accessed for cleaning and servicing of assemblies therein by removing the retaining plate 16 fastened to the housing 10.
The [0073] spherical roller 9 may be comprised of a homogeneous material, such as steel, plastic or rubber, the texture and resiliency of which would depend on the need for durability, friction or softness. Alternately, it could be made from a heterogeneous material or combination, such as a rubber surface bonded to a steel core, or a heterogeneous composition such as a hard plastic core with a resilient covering. For example, a hardened rubber roller with a frictional outer surface may be suitable in sports-related applications to provide a good rolling action with desirable surface friction characteristics to enhance control and provide long wear. Other satisfactory materials might include metal or plastics with or without a filler. The spherical rollers preferably are solid and may be of the same material throughout or may be a composite material exemplified by a golf ball.
The omnidirectional [0074] roller apparatus housing 10 may be manufactured of a metal or impact-resistant plastic. The housing, although shown attached with screws 18 to a platform, such as in a dolly or skateboard, may be made readily detachable and replaceable also by means of a screw-in housing [FIG. 11], as just one example. In any event, a housing may contain as many hollow cavities and ball systems as is required for an application, and may be mounted on rear and forward portions of a platform in a straight line, in each comer, or in any position determined to be advantageous for a particular application.
In practice, the spherical roller apparatus is sized to meet requirements of the application. For example, a skateboard [Example 2, infra], may require a spherical roller to be about the size of a standard baseball or even a softball. Typically, however, in sports applications such as skates or skateboards, the diameter of the balls may be on the order of 2″ to 3″ more or less. Industrial applications would require sizes based on intended use. [0075]
The [0076] housing 10, in the illustrated embodiment FIGS. 1-3, has a formed spherical socket 12 with an annular bottom opening 14, through which the lower portion of the spherical roller 9 protrudes. The diameter of the opening 14 is made slightly smaller than that of the spherical roller 9 by a retaining ring 16, in order to retain the spherical roller within the socket whenever there is an upward force exerted on the housing. The housing may be beveled about its sides [FIGS. 7, 8] or cut way [FIG. 12] in order to facilitate omnidirectional tilting, thereby enhancing freedom of action. To reduce friction as the spherical roller contacts the edge of the socket opening, a self-lubricating lip, such as a coating of Teflon or the like may be fused about the socket edge as in FIG. 1, 2, or the spherical roller could be supported by Teflon screws as in FIG. 12, 137.
Each [0077] spherical roller 9 communicates and is supported within its socket by means of a triad system of small swivel casters 8, as shown in FIGS. 1, 2, 3, and in more detail in FIG. 4, 10. The spherical roller is cradled within, or crowned by (depending on orientation), a system of supports including at least three swivel assemblies (small casters) stereospatialy located above, and in contact with, the spherical roller. The swivel assemblies are fixed within bores 4 in the upper spherical surface of the socket 12, precisely geometrically disposed to each other; the lower surface of each wheel 8 contacting the spherical roller 9 at its upper surface, or vice versa, as in Example 3 infra.
As best shown in FIG. 4, a rolling support wheel [0078] 42 is rotatably mounted on a shaft 40 extending transversely and attached at its ends to the inner surface of the rotating bearing assembly 48, in a position slightly offset from the center of the bearing assembly. Each bearing assembly is free to rotate independently of the other bearing assemblies. This configuration is best shown in FIGS. 1-3 where the bearing wheel 8 is relatively small in diameter and engages the top portion of the spherical roller 9. In this configuration, the different areas of a rotating spherical roller will experience similar surface speeds because the axis of rotation is identical in all contacting surfaces. By employing the geometric configurations in the manner shown in FIG. 1, the spherical roller is free to rotate forward, backward and sideways, and is evenly supported. Due to the offset of the load-bearing wheel shafts 7 from the center, a slight resistance against sidewise rotation of the spherical roller 9 is provided by momentum, so that some control over the direction and movement is effectuated. Because the restriction to side motion is very slight, and can be overcome by a slight shift in weight, there is much more freedom to perform free-form maneuvers. And, since the spherical rollers are omnidirectional in the line of movement, and the sides of the frame are beveled, the user can tilt the roller caster from one side to the other in a manner not possible with four-wheeled roller systems.
The contact areas of the swivel wheels (small casters) may be rounded, or preferably, flat to prevent their pressing into the surface of the spherical roller. They may be made from various materials, including metal and plastics such as nylon or Teflon, which are tough and durable and provide good rolling action with low friction characteristics. [0079]
Referring now more particularly to FIGS. 2, 12, of the drawings, there is shown means for replacing the spherical roller in the event that the spherical roller wears out after a period of extended use, or just for routine cleaning. In FIG. 2, the [0080] housing 10 is provided with a removable retaining ring 16 through which the spherical roller 9 projects. The ring 16 may be held in position by screws 18, as shown, or by any other suitable means; and when in position, will hold the spherical roller 9 within its socket. It will be understood that by removing the screws 18, the ring 16 may be disconnected to thereby enlarge the opening and remove the ball or service the within assemblies as required. In FIG. 12, the spherical roller can be supported by a similar ring 135, which may contain Teflon screws 137 to provide a sliding surface. In this example, screws alone can contain the spherical roller.

B. EXAMPLE TWO

OMNIDIRECTIONAL SKATEBOARD

Another particularly preferred and more specialized embodiment of this invention is an omnidirectional skateboard shown in FIG. 5. This board comprises an integral, elongated, structurally rigid, single-piece, formed platform for supporting a skater. The platform has a central longitudinal axis along the length of the board, with a flat [0081] central portion 50 and bilateral, upwardly inclining wings 51 extending laterally from the center portion. Unlike a conventional skateboard, this invention does not require identification of fore and aft portions, as it is equally effective whatever end the user chooses to go forward. This allows a monumental increase in freedom of movement.
This skateboard has one or more longitudinally spaced [0082] spherical roller assemblies 60, as described hereinbefore, centrally attached to the underside of the flat central portion 50 of the platform structure. Each assembly housing 56 contains at least one spherical roller caster configured to have the capability of independent omnidirectional rotation.
As already described generally and reiterated below, each such [0083] spherical roller apparatus 60 attached 59 to the platform comprises a housing 56 having at least one spherical cavity 57 defining a downwardly open spherical socket to hold a spherical roller 58. There are at least three shallow cylindrical bores in the upper surface of the spherical socket, positioned to form an equilateral triangle, each bore having one of the load-bearing swivel caster assemblies hereinabove described extending in a spherical triangular relationship in contact with the spherical roller.
This skateboard also has a plurality of equally spaced, longitudinally aligned fixed-[0084] wheel assemblies 52 attached to the underside of each of the upwardly inclined wings 51 of the platform structure. The fixed-wheel assemblies are not new in the art, but are described here because they facilitate a new use of the novel roller caster 60 that is this invention. Each fixed wheel-assembly has a wheel 53 mounted on a fixed shaft 55 in a bracket 54 oriented transversely to the central longitudinal axis of the platform, and configured so as to maintain the fixed-wheels in axial alignment relative to the platform structure. FIG. 6 depicts an alternate embodiment having two spherical roller casters of this invention attached in tandem.
As shown in FIG. 7, the body weight of a skater is supported primarily by the spherical roller [0085] 75 apparatus when the platform is in the non-tilted orientation. This permits movement of the roller board in a direction of travel extending along the longitudinal axis, transversely, or at any angle thereto. Steering the roller board is accomplished by tilting the platform structure about the central longitudinal axis. Each fixed-heel 70 mounted on a shaft 72 in a bracket 71 is biased to rotate in a direction of travel along the longitudinal axis. The skater may selectively cause an increased portion of body weight to be supported by one or more of the plurality of fixed-wheel assemblies as shown in FIG. 8.
The platform is wider and longer than a normal skateboard deck, and typically measures 11 inches wide and 40 inches long. This additional size makes this skateboard easier to ride and control. FIG. 7 shows a cross-section of the platform, cut perpendicularly to the longitudinal center line axis. The shape of the platform is rather concave, with its sides gently angled upward from the base, to help the rider transfer exerted force laterally. Two basic types of mechanical components are mounted to the underside of the platform [FIGS. 5, 6, [0086] 7, 8]; one or more roller casters and a plurality of fixed-wheel assemblies. Shown in FIG. 5, are eight fixed-wheel assemblies 54 positioned parallel to the longitudinal centerline 50. One or more omnidirectional spherical roller caster(s) 60 are centrally positioned between the parallel fixed wheels [see also FIG. 6]. The fixed-wheel assemblies 54 provide a different function and effect on maneuvering from that of the omnidirectional pivoting roller assemblies. This combination results in a heretofore-unattainable level of freedom and similarity to snowboarding.
The larger than conventional platform of the skateboard of this invention results in a wider and longer wheelbase for the fixed wheels [0087] 56 to provide additional stability. Additionally, the spherical roller caster housing under the central portion of the board may be provided with a number of cavities for selective use, depending on experience and ability of the rider. More widely spaced-apart rollers would result in greater stability, while a single central roller (as in FIG. 5) would impart the greatest maneuverability
Referring now to FIG. 11, an alternate embodiment of the present invention depicts a screw-in type of [0088] caster housing 114, allowing ready replacement of worn or damaged casters, or ready adjustment of the height of the platform for negotiating rougher terrain, or making sharper cuts. The spherical casters provide omnidirectional motion. A spherical roller 9 remains in constant contact with the ground and can align itself with the direction of force exerted on platform. There is no bias spring as in the Strand patent; rather very slight bias is introduced by the momentum of motion due to the offset load-bearing small casters 4 above the spherical roller, as already described. This bias simulates the natural bias tendency of a snowboard. The bias thus created does not pose an impediment to lateral or rotational maneuverability, it merely aids control in whatever the desired direction of travel.
Another preferred embodiment of the roller caster is shown in FIG. 12. Here, the [0089] housing 131 is scalloped, having arches 132, and legs 134 supporting a retaining ring 135 (optional). This version opens the spherical roller 136 to the environment, and permits maximum tilting. In one embodiment, the spherical roller is retained (with or without the retaining ring) by self-lubricating adjustable points 137 located anywhere on the retaining ring, or on each of the extended legs 134 of the arches. It has been discovered that, contrary to conventional thinking, the spherical roller remains cleaner when exposed to the elements. Prior attempts to provide closer cavity tolerances and sealing lips resulted in more frequent jamming and more difficult cleaning. 133 are the approximate location of one of the load-bearing small caster assemblies.
The success of the omnidirectional roller skateboard can be attributed to the interaction of the relatively resistance-free omnidirectional motion of the spherical roller system and the fixed-wheel lateral support; the first providing previously unachievable maneuverability, the latter providing the desired control. [0090]
FIG. 7 shows the skateboard when the rider's weight is perfectly centered over the platform. It can be seen that the spherical roller housing [0091] 74 is tapered to provide clearance for the protruding spherical roller 75. It can also be seen that the fixed wheels 70 are above the skating surface, with skater's weight directly on the central spherical roller 75. Under these circumstances, there is virtually no resistance to travel in any direction aside from the slight momental force of weight in motion, supplemented by the slightly offset load-bearing small swivel casters.
FIG. 8 shows the position of the various rollers relative to the surface as weight is shifted to one side. By shifting his or her weight from one side to another, the skater an “carve,” as with conventional skateboards or skis without sliding out of control, more or less equivalent to the action of a snowboard. To slow down, the skater merely shifts his or her weight to the side. This weight transfer engages the fixed wheels on that side, greatly increasing friction to slow the board. The amount of speed control varies with the amount of weight shifted. Unlike the casters in Strand, there is no need for a bias spring to effect force in order to prevent wobbling. Here, the spherical roller, due to its spherical nature, close tolerances and precise triangulation (spacing), encounters no vibration and the result is wobble-free motion. [0092]
Accordingly, it can be seen that the roller board brings a new freedom of movement to skateboarding, approximating many of the movements found in snowboarding. The roller board provides the ability to “carve,” as a conventional skateboard can, where leaning weight to one side causes the device to turn in that direction. It permits a mode of omnidirectional motion, where the device can easily travel forwards, backwards, sideways or in circular fashion. [0093]
The roller board also provides a user interface that simulates the balance characteristics of snowboarding and other board sports, where the omnidirectional mode is engaged when the rider's weight is relatively evenly distributed across the board and this mode can be exited by transferring weight to the board's edge. It allows rotations repeatedly without lifting the board while in motion. [0094]
As a final advantage, the omnidirectional roller skateboard, the “Omniboard,” is remarkably simple in design and economical to produce and maintain. [0095]

C. EXAMPLE THREE

OMNIDIRECTIONAL PLATFORM

Another important and highly preferred embodiment of this invention is an omnidirectional platform, such as one appending a conveyor system. This platform may contain a plurality of attached housings as shown in FIG. 9, each having one or more concave spherical cavities. Attachment to a platform may be as illustrated in FIG. 2, 3, or screwed in as in FIG. 11. As described before, each cavity has an annular opening; however, in this case the opening is on the upper side of the housing (i.e., the housing is inverted), to form one or more spherical socket capable of containing a [0096] spherical roller 9. Such a platform can have as many spherical roller assemblies as is required, and in various configurations. A linear grid configuration is shown in FIG. 9.
As before, there is a plurality of cylindrical bores equidistantly geometrically disposed on the lower surface of the spherical socket, opposite the topside annular opening. There is a matching number of swivel assemblies disposed within the cylindrical bores in the internal, bottomside surface of each of the sockets. Each swivel assembly contains a shaft rotatably mounted within a space defined by an annular bearing and attached thereto, forming a longitudinal axis of rotation transverse to the axis of rotation of the bearing. The shaft rotatably supports a swivel that rollably interfaces between the sockets and a spherical roller in each of the housing hollow sockets. This results in the swivel assemblies rollably interfacing between the concave spherical cavities and the spherical roller. The spherical roller concomitantly rollably interfaces between the bearing assemblies and a surface with which the spherical roller assembly communicates, allowing omnidirectional movement of a surface over the platform. [0097]
This embodiment, as do the other embodiments, has means for retaining the spherical roller within the housing, such that a portion of the spherical roller protrudes from the housing, thereby allowing contact between the spherical roller and the surface of an object moved over it. Also contained is the retainer ring, or plate, to quickly open and close the housing, for performing repairs and for cleaning. [0098]
The spherical roller may be retained and supported within the concave socket by a removable annular retaining plate, wherein only a portion of the spherical roller extends beyond the annular retaining plate, although in some applications, this may not be necessary since the force of gravity forces the spherical roller against the load-bearing wheels. The swivel assemblies may have splines and be press-fitted into each of the triad of splined shallow cylinder cavities. Again, as in embodiments referred to hereinbefore, the means to open the housing for cleaning and servicing of the roller wheel housing and assemblies therein may be a removable retaining ring fastened to the housing. [0099]
The spherical roller may be comprised of a homogeneous material, such as steel, hard rubber or plastic, or of heterogeneous material, such as a steel core covered with a rubber skin, or a composition such as a plastic core covered with a resilient surface. [0100]
In accordance with the preceding explanation, variations and adaptations of the omnidirectional roller caster in accordance with the present invention will suggest themselves to a practitioner of the mechanical arts. [0101]
Pursuant to the above-described and other possible variations and adaptations of the present invention, the scope of the invention should be determined in accordance with the following claims only, and not solely in accordance with those embodiments within which the invention has been taught. [0102]

Claims

What is claimed is:

1. A caster comprising:

a sphere;

a housing defining (i) an imaginary hemispherical cavity, having a radius between its pole point and center, juxtaposed relative to substantially half the sphere, and (ii) at least three imaginary bores in substantially equilateral geometrical configuration within the imaginary hemispherical cavity and about its pole, each imaginary bore having an axis that both converges towards the center of the sphere and that is at an acute angle to the radius of the imaginary hemispherical cavity, and;

an assembly extending from within each bore to contact the surface of the sphere, each assembly including

an annular bearing mounted to the housing centrally about the axis of the bore for free independent rotation about the axis of the bore,

a shaft mounted internally within the annular bearing at a positional offset from the axis of the bore, and

a wheel rotatably supported by the shaft and contacting the sphere for the support thereof;

wherein the collective shaft-mounted wheels of the collective shafts of the collective caster assemblies create a loading surface permitting omnidirectional rotation of the contacted sphere;

wherein the offset of the shafts and of the wheels that are supported by the shafts from the converging axis of the imaginary bores make that such force moment as is developed upon changing rotational direction of the sphere causes rotation of the annular bearing of one or more of the assemblies, facilitating that the change in rotational direction transpire smoothly.

2. The caster according to claim 1

wherein the acute angle is 60 degrees or less.

3. The caster according to claim 1, wherein the sphere roller is contained within the housing cavity by a removable annular retainer.

4. The caster according to claim 1, wherein the caster assembly of the internal caster has splines on its annular outer surface, and is press-fitted into a matching splined bore, thereby securing the caster within the bore while allowing free rotational movement.

5. The caster according to claim 1, wherein the sphere is comprised of a homogeneous material, with a texture and resiliency depending on the particular need for durability, friction or softness.

6. The caster according to claim 1, wherein the sphere is comprised of a heterogeneous material, having a hard core with a resilient surface.

7. An omnidirectional skateboard, comprising:

a. an integral, elongated, structurally rigid, single-piece platform for supporting a user, the platform having

i a flat central portion with a longitudinal axis,

bilateral upwardly-inclining extensions from the central portion, and

ii fore and aft upwardly-angled extensions;

b. at least one spherical roller assembly longitudinally spaced and centrally attached to the underside of the flat central portion of the platform, each assembly having

i. a housing, comprising

(1) at least one downwardly-open spherical cavity defined by at least three shallow cylindrical bores in the inner, upper surface of the housing defining the spherical cavity, positioned to form an equilateral geometrical configuration with the axis of each bore aligned to the center nucleus of the spherical roller,

ii. a plurality of proportionately small internal caster assemblies fitted within the bores, extending in a spherical geometrical relationship axially aligned to the center of the cavity, each assembly having,

(1) an annular bearing,

(2) a shaft transversely mounted within and offset from the center of the bearing, the longitudinal axis of which is transverse to the rotation of the bearing,

(3) a wheel, rotatably supported by the shaft,

wherein a loading surface is created that is capable of imparting omnidirectional rotation when in contact with a surface,

c. a large spherical roller freely mounted within the spherical cavity of the housing, rollably communicating with the wheel,

thereby interfacing between the loading surface of the spherical cavity and a surface onto which the roller apparatus is imparted omnidirectional movement;

d. means for containing the spherical roller within the housing, such that a portion of the spherical roller protrudes from the housing, thereby allowing contact between the spherical roller and the surface, and

e. means for opening the housing to permit repairs and cleaning of the omnidirectional apparatus;

f. a plurality of equally spaced, longitudinally aligned fixed-wheel assemblies attached to the underside of each of the upwardly inclined wings of the platform structure, each fixed wheel assembly mounted on a shaft means fixedly oriented transversely to the central longitudinal axis of the platform, the fixed-wheel mounting means being configured to maintain the fixed-wheels mounted thereon in axial alignment relative to the platform structure.

8. A platform permitting unbiased omnidirectional movement of materials over its surface, comprising:

an integral, dimensional, structurally rigid platform;

a plurality of housings attached to a plane, each housing having at least one concave spherical cavity, each cavity having an annular opening to the exterior of the housing disposed opposite the attachment;

a plurality of cylindrical bores equilaterally disposed on the concave inner surface of the housing opposite to the annular opening, each bore aligned to the center of the cavity;

a spherical roller;

a smaller internal caster assembly fitted into each cylindrical bore, the caster assembly containing

an annular bearing fitted within the cylindrical bore,

a shaft rotatably mounted within a void space defined by the annular bearing, with a longitudinal axis of rotation transverse to the axis of rotation of the bearing,

a wheel rotatably supported by the shaft for rollably interfacing between the inner surface of the cavity and the spherical roller, thereby providing a loading surface,

wherein the spherical roller concomitantly rollably interfaces between the bearing assemblies and a surface with which the spherical roller communicates, allowing omnidirectional movement;

means for retaining the spherical roller within the housing, such that a portion of the spherical roller protrudes from the housing, thereby allowing contact between the spherical roller and a surface; and

means for opening the housing, for performing repairs and cleaning the contents thereof

9. The platform according to claim 8, wherein the plurality of internal caster assemblies are disposed in equilateral geometric configurations about the spherical roller, forming load-supporting surfaces axially aligned to the spherical roller's center nucleus, thereby capable of imparting uninfluenced omnidirectional rotation to the spherical roller.

10. The platform according to claim 8, wherein the spherical roller is retained within the housing by a removable annular retainer, wherein only a portion of the spherical roller extends beyond the annular retainer.

11. The platform according to claim 8, wherein the spherical roller is comprised of a homogeneous material depending on the nature of the surface contacted and therefore the requirement for particular durability, friction or softness.

12. The platform according to claim 8, wherein the spherical roller is comprised of a heterogeneous material, having a hardened core with a resilient surface.