Wheeled board toy assembly

Claim 2

A skiing instruction device comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaCed apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon and for enabling the platforms to be rotated about an axis substantially parallel to the longitudinal axis of the platforms whereby the user utilizes the platforms to simulate the techniques of snow skiing; and d. means flexibly coupled to the trailing portion of each of the platforms for maintaining the trailing portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship.

Claim 3

A skiing instruction device in accordance with claim 1 in which each of the pair of wheel assemblies of each platform is mounted on the lower surface of the platforms substantially along the longitudinal axis thereof.

Claim 4

A skiing instruction device in accordance with claim 1 in which the means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon comprises a link which is flexibly connected to a leading portion of each of the platforms.

Claim 5

A skiing instruction device in accordance with claim 1 in which the additional means for maintaining the trailing portions at a predetermined distance with respect to one another to enable the platforms to travel in a side by side relationship comprises an additional link which is flexibly connected to the trailing portion of each of the platforms.

Claim 6

A wheeled board assembly for recreational use and adapted for use as a ski instruction device, comprising: a. a pair of wheeled skate boards which are generally rectangular in shape, each of said skate boards having a front end and a rear end, one skate board being used for each of the feet of the user; b. a plurality of skate board wheels affixed to the underside of each of said skate boards, on which skate board wheels said skate boards roll during use; c. a pair of link boards, which are generally rectangular in shape, one said link board being a front link board and being coupled at the front end of each of said skate boards and the other link board being a rear link board and being coupled at the rear end of said skate boards, the skate boards being arranged approximately perpendicular to said link boards; d. a plurality of link board wheels, at least one of said link board wheels being positioned on the underside of each of said link boards, on which link board wheels said link boards roll; e. a pair of outrigger boards which are generally rectangular in shape and which are rotatably affixed to said front link board, one said outrigger board being affixed to each end of said front link board and the longitudinal axis of said outrigger boards being approximately in line with the longitudinal axis of said front link board, each outrigger board having an outer end which is the end further away from said link board; f. a plurlaity of outrigger wheels, at least one of said outrigger wheels being positioned on the underside of each of said outrigger boards, one of said outrigger wheels being positioned at the outer end on the underside of each of said outrigger boards; and g. a pair of ski poles, one of said ski poles being affixed to each of said outrigger boards, the ski poles being affixed at the outer end of said outrigger boards.

Claim 7

A wheeled board assembly for recreational use and adapted for use as a ski instruction device, comprising: a. a pair of wheeled skate boards which are generally rectangular in shape, each of said skate boards having a front end and a rear end, one skate board being used for each of the feet of the user; b. a plurality of skate board wheels affixed to the underside of each of said skate boards, on which skate board wheels said skate boards roll during use; c. a pair of link boards, which are generally rectangular in shape, one said link board being a front link board and being coupled at the front end of each of said skate boards and the other link board being a rear link board and being coupled at the rear end of said skate boards, the skate boards being arranged approximately perpendicular to said link boards; d. a plurality of link board wheels, at least one of said link board wheels being positioned on the underside of each of said link boards, on which link board wheels said link boards roll; e. a pair of outrigger boards which are generally rectangular in shape and which are rotatably affixed to said front link board, one said outrigger board being affixed to each end of said front link board and the longitudinal axis of said outrigger boards being approximately in line with the longitudinal axis of said front link board, each outrigger board having an outer end which is the end further away from said link board; f. a plurlaity of outrigger wheels, at least one of said outrigger wheels being positioned on the underside of each of said outrigger boards, one of said outrigger wheels being positioned at the outer end on the underside of each of said outrigger boards; and g. a pair of ski poles, one of said ski poles being affixed to each of said outrigger boards, the ski poles being affixed at the outer end of said outrigger boards.

Claim 8

The wheeled board toy assembly according to claim 5 wherein each of said skate boards comprises six skate board wheels, said skate board wheels being arranged in groups of three wheels, one group of three wheels being arranged at the front end on the underside of each said skate board, the other group of three wheels being arranged on the underside of the rear end of said skate board, each said skate board further comprising a slat which is generally rectangular in shape, and whose dimensions in length, width and thickness are each smaller, respectively, than the corresponding dimensions of said skate board, said slat being affixed to the underside of said skate board, the longitudinal axis of said slat being approximately parallel to the longitudinal axis of said skate board, said slat being arranged approximately in the middle of said skate board, one of said skate board wheels from the front group of three wheels being positioned on said slat and one of said skate board wheels from the rear group of three wheels being positioned on said slat, whereby said skate board tends to roll in the direction in which said skate board is tilted.

Claim 9

A wheeled board toy assembly according to claim 6 wherein each group of three wheels is arranged in a triangular configuration on the underside of each said skate board, two of the wheels of said group of three wheels forming the base of the triangular configuration and the third wheel of said group of three wheels forming the apex of said triangular configuration.

Claim 10

A wheeled board toy assembly according to claim 7 wherein the wheel forming the apex of the triangular configuration of one group of three wheels is positioned at the front end on the underside of said slat and the two wheels of said group of three wheels which form the base of the triangular configuration are arranged side by side, opposed to one another, on the underside of the front end of said skate board and at the same distance from the front end of said skate board; and wherein the wheel forming the apex of the triangular configuration of the other group of three wheels is positioned at the rear end on the underside of said slat and the two wheels of said group of three wheels which form the base of the triangular configuration are arranged side by side, opposed to one another, on the underside of the rear end of said skate board and at the same distance from the rear end of said skate board.

Claim 11

A wheeled skate board according to claim 8 wherein the only skate board wheels are in contact with the ground when the skate boards are perfectly level are the skate board wheels which are mounted on said slants and which form the apex of the triangular configuration of each group of three wheels.

Claim 12

A wheeled skateboard according to claim 5 wherein said skate boards are coupled to said link boards nuts and bolts which allow both skate boards to rotate about their longitudinal axis with reference to both link boards.

Claim 13

The wheeled board toy assembly according to claim 5 wherein said outrigger boards are rotatably affixed to said front link board by means of hinges.

Claim 14

A wheeled board toy assembly according to claim 5 wherein each outrigger board has a well at said outer end of said outrigger board into which said ski poles fit.

Claim 15

A wheeled board toy assembly according to claim 12 wherein each said outrigger board has means disposed in the well of each outrigger board for flexibly connecting the end of each ski pole opposite from the end of the ski pole grasped by the user to said outrigger board.

Claim 16

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; and d. further comprising means for mounting each of the pair of wheel assemblies to caster with respect to the platform, the axis of the caster of each of the different pair of wheel assemblies extending toward the platform in a region thereof between each of the pair of wheel assemblies, the caster of each of the pair of wheel assemblies enabling each of the platforms to be directed toward a common change of direction by the shifting of the weight of the user thereon.

Claim 17

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; and d. further comprising means for mounting each of the pair of wheel assemblies to caster with respect to the platform, the axis of the caster of each of the different pair of wheel assemblies extending toward the platform in a region thereof between each of the pair of wheel assemblies, the caster of each of the pair of wheel assemblies enabling each of the platforms to be directed toward a common change of direction by the shifting of the weight of the user thereon.

Claim 18

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; and e. the link having an additional wheel mounted upon the surface of the link facing in the direction of the lower surfaces of the platforms for supporting the link with respect to a rolling surface when the link is moved toward the rolling surface.

Claim 19

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; and e. the link having an additional wheel mounted upon the surface of the link facing in the direction of the lower surfaces of the platforms for supporting the link with respect to a rolling surface when the link is moved toward the rolling surface.

Claim 20

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; and e. further comprising a pair of outriggers each being flexibly mounted to a different one of the opposite end portions of the link and extending substantially away from one another in a direction transverse to the length of each of thE platforms, and means for connecting each hand of the user to a different one of the outriggers, whereby the outriggers and the connecting means attached thereto can provide stability to the user.

Claim 21

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; and e. further comprising a pair of outriggers each being flexibly mounted to a different one of the opposite end portions of the link and extending substantially away from one another in a direction transverse to the length of each of thE platforms, and means for connecting each hand of the user to a different one of the outriggers, whereby the outriggers and the connecting means attached thereto can provide stability to the user.

Claim 22

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; e. further comprising a pair of outriggers each being flexibly mounted to a different one of the opposite end portions of the link and extending substantially away from one another in a direction transverse to the length of each of the platforms, and means for connecting each hand of the user to a different one of the outriggers, whereby the outriggers and the connecting means attached thereto can provide stability to the user; and f. in which the means for connecting each hand of the user to a different one of the outriggers comprises a pair of upwardly extending rods each connected at the lower end thereof to a different one of the outriggers and having an upper end portion which is adapted to be grasped by a different hand of the user.

Claim 23

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; e. further comprising a pair of outriggers each being flexibly mounted to a different one of the opposite end portions of the link and extending substantially away from one another in a direction transverse to the length of each of the platforms, and means for connecting each hand of the user to a different one of the outriggers, whereby the outriggers and the connecting means attached thereto can provide stability to the user; and f. in which the means for connecting each hand of the user to a different one of the outriggers comprises a pair of upwardly extending rods each connected at the lower end thereof to a different one of the outriggers and having an upper end portion which is adapted to be grasped by a different hand of the user.

Claim 24

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; e. further comprising a pair of outriggers each being flexibly mounted to a different one of the opposite end portions of the link and extending substantially away from one another in a direction transverse to the length of each of the platforms, and means for connecting each hand of the user to a different one of the outriggers, whereby the outriggers and the connecting means attached thereto can provide stability to the user; and f. further comprising a pair of wheels each of which is attached to the lower surface of a different one of the outriggers to support the outriggers with respect to the rolling surface upon which the instruction device is to be operated.

Claim 25

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. means for maintaining the leading portions of the platforms at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon including a link which is flexibly connected to a leading portion of each of the platforms; e. further comprising a pair of outriggers each being flexibly mounted to a different one of the opposite end portions of the link and extending substantially away from one another in a direction transverse to the length of each of the platforms, and means for connecting each hand of the user to a different one of the outriggers, whereby the outriggers and the connecting means attached thereto can provide stability to the user; and f. further comprising a pair of wheels each of which is attached to the lower surface of a different one of the outriggers to support the outriggers with respect to the rolling surface upon which the instruction device is to be operated.

Claim 26

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platforms; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; and d. further comprising pairs of auxiliary wheels, each pair of auxiliary wheels being mounted with respect to the lower surface of the platform between a different one of the pairs of wheels and the end portion of the platform adjacent thereto, each of the wheels of a pair of auxiliary wheels being mounted on different opposite sides of the longitudinal axis of the platform and having its axis of rotation extending at an angle to the length of the platform and intersecting the longitudinal axis of the platform between the region of the auxiliary pair of wheels and the end of the platform adjacent thereto, the running surface of each of the auxiliary wheels being disposed above a running surface when the platform is supported thereon by the pairs of wheels, whereby an auxiliary wheel of each pair on a given platform in conjunction with the pair of wheels enables the platform to be directed in a curvilinear direction.

Claim 27

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platforms; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; and d. further comprising pairs of auxiliary wheels, each pair of auxiliary wheels being mounted with respect to the lower surface of the platform between a different one of the pairs of wheels and the end portion of the platform adjacent thereto, each of the wheels of a pair of auxiliary wheels being mounted on different opposite sides of the longitudinal axis of the platform and having its axis of rotation extending at an angle to the length of the platform and intersecting the longitudinal axis of the platform between the region of the auxiliary pair of wheels and the end of the platform adjacent thereto, the running surface of each of the auxiliary wheels being disposed above a running surface when the platform is supported thereon by the pairs of wheels, whereby an auxiliary wheel of each pair on a given platform in conjunction with the pair of wheels enables the platform to be directed in a curvilinear direction.

Claim 28

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. further comprising pairs of auxiliary wheels, each pair of auxiliary wheels being mounted with respect to the lower surface of the platforms between a different one of the pairs of wheels and the end portion of the platform adjacent thereto, each of the wheels of a pair of auxiliary wheels being mounted on different opposite sides of the longitudinal axis of the platform and having its axis of rotation extending at an angle to the length of the platform and intersecting the longitudinal axis of the platform between the region of the auxiliary pair of wheels and the end of the platform adjacent thereto, the running surface of each of the auxiliary wheels being disposed above a running surface when the platform is supported thereon by the pairs of wheels, whereby an auxiliary wheel of each pair on a given platform in conjunction with the pair of wheels enables the platform to be directed in a curvilinear direction; and e. in which the wheels of each of the pairs of auxiliary wheels oN the same side of the longitudinal axis of the platform are disposed along a common substantially curvilinear line which intersects each of the pairs of wheel assemblies, whereby each platform can be selectively supported by a wheel of each of the pairs of auxiliary wheels and the pairs of wheel assemblies when the platform is being directed to move along a curved line of travel.

Claim 29

A wheeled board toy assembly comprising: a. a pair of elongated platforms each having an upper surface adapted to receive a different foot of the user when the foot is disposed along the length of the platform; b. a pair of wheel assemblies each having at least one wheel mounted spaced apart with respect to one another along the lower surface of each of the pair of platforms, the axis of rotation of each wheel extending substantially in a transverse direction with respect to the length of the platform, the wheel assemblies enabling the platforms to travel along a rolling surface in the direction of the length of the platforms when the user is standing thereon; c. means flexibly coupled to the leading portion of each of the platforms for maintaining the leading portions at a predetermined distance with respect to one another to enable the platforms to travel together in a side-by-side relationship when the user is standing thereon; d. further comprising pairs of auxiliary wheels, each pair of auxiliary wheels being mounted with respect to the lower surface of the platforms between a different one of the pairs of wheels and the end portion of the platform adjacent thereto, each of the wheels of a pair of auxiliary wheels being mounted on different opposite sides of the longitudinal axis of the platform and having its axis of rotation extending at an angle to the length of the platform and intersecting the longitudinal axis of the platform between the region of the auxiliary pair of wheels and the end of the platform adjacent thereto, the running surface of each of the auxiliary wheels being disposed above a running surface when the platform is supported thereon by the pairs of wheels, whereby an auxiliary wheel of each pair on a given platform in conjunction with the pair of wheels enables the platform to be directed in a curvilinear direction; and e. in which the wheels of each of the pairs of auxiliary wheels oN the same side of the longitudinal axis of the platform are disposed along a common substantially curvilinear line which intersects each of the pairs of wheel assemblies, whereby each platform can be selectively supported by a wheel of each of the pairs of auxiliary wheels and the pairs of wheel assemblies when the platform is being directed to move along a curved line of travel.