Abstract:
An operator-propelled, four-wheel vehicle uses a treadmill to drive two rear wheels through a bicycle type derailleur and sprocket gear shifter which provides gear changing capability. The front wheels, each of which have disk brakes, are steered by an automotive type steering apparatus. A vertical extension from the steering mechanism at the front of the vehicle mounts a horizontal steering bar to provide steering control. The steering bar also mounts control grips and cables for the front disk brakes and clutch assembly, as well as the gear shifter. An automatic breaking system ensures that an unmanned vehicle will remain in place.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to operator-propelled and directed land vehicles. 
   2. Description of the Related Art 
   There are a variety of operator propelled land vehicles. These include such things as bicycles, miniature automobiles, roller skates and scooters. None of these vehicles are intended to provide a variable walking or running exercise when carrying an individual from place to place. 
   SUMMARY OF THE INVENTION 
   This four-wheeled, treadmill-driven vehicle provides an individual with a method of selecting a desired walking or running exercise level while traveling from place to place under his own propulsion. The vehicle has a rectangular shaped chassis with four corner mounted wheels. A treadmill drives the rear wheels trough a chain. A bicycle derailleur gear changer is used to change the ratio of the vehicle&#39;s forward motion versus the treadmill belt motion. 
   A planar platform of essentially the same size and shape as the chassis is pivotably attached to the front of the chassis. The platform inclines upward from the rear of the chassis. The platform has three rotatably mounted shafts which extend transversely across the platform. A first and a second shaft are located across the front end, and a third shaft is located across the rear end. Front and rear rubber rollers enclose the first and third shafts within the outer lateral edges of the platform. The treadmill belt is wrapped lengthwise around the platform enclosing both rollers. A platen is attached to the upper surface of the platform to minimize friction between the belt and the platform. The front rubber roller is keyed to the first shaft to convert movement of the treadmill belt to rotation of the shaft. 
   The first and second front shafts have gears mounted on corresponding ends which mesh with each other. This engagement transmits the rotation of the belt driven first shaft to the second front shaft and reverses the direction, relative to that of the first shaft, of the second shaft&#39;s rotation. The opposite end of the second shaft has a larger gear attached to its end. 
   The third shaft has a number of different sized sprockets in successive sizes attached to the rear axle. These sprockets and the larger gear on the second front shaft are connected together by a chain. A derailleur engaging the chain is mounted between the sprockets and the front gear. This derailleur changes the ratio of the belt movement to movement over the ground by selecting successively different sized sprockets. 
   The rear wheels are attached to the rear shaft to transmit rear shaft rotation, driven by the chain from the second front shaft, to movement over the ground. A control cable from the derailleur to the front of the vehicle provides ready operator gear changer control. With this arrangement a forward facing operator driving the upper run of the treadmill rearward will move the vehicle in a forward direction. 
   An automatic parking braking apparatus is provided at the rear of the vehicle. The platform has a pair of rearward extensions which are supported by coil springs from the chassis. When there is no operator on the vehicle, the springs will be at their minimum compression and the rear of the platform will be elevated. A brake drum, in the form of a relatively large cylinder, is attached around the rear axle. A downward extension terminates in an inward curved extension which mates with the brake drum. The curved extension is positioned directly under the break drum. When there is no operator on the platform and the rear of the platform is elevated, the curved portion of the extension will engage the break drum thereby providing an automatic parking brake. 
   The front wheels are pivotably connected to the front of the vehicle through an automotive type steering arrangement. The front wheels are steered by the operator by means of a steering bar extending generally across the vehicle front. The steering bar is attached to the automotive steering arrangement through a pivotably mounted vertical rod. The front wheels also have disk brakes which are controlled by a cable extending to the steering bar where it is attached to a lever for easy operator access. 
   This operator propelled vehicle provides exercise for the user while simultaneously traveling from one location to another. Steering is readily accomplished by the steering bar at the front of the vehicle. The derailleur cable and break cables are attached to the steering bar for ready access. The automatic breaking system ensures that an unoccupied vehicle will remain in place even on a steep slope. The operator can disengage the rear axle from the drive train via a clutch mechanism attached to the rear axle assembly. The clutch is controlled by a cable which extends to the steering bar where it is attached to a lever for easy operator access. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects and features of the present invention will become more manifest to those skilled in the art upon a reading of the following description, taken in connection with the accompanying drawings and wherein: 
       FIG. 1  is an isometric view of the vehicle; 
       FIG. 2  is a top view of the vehicle; and 
       FIG. 3  is a side view of the vehicle. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1-3  show vehicle  10 . Vehicle  10  has an essentially rectangular shaped chassis  12  with a generally similar sized and shaped frame  14  mounted in an upwardly inclined attitude in a forward direction across the upper surface. Chassis  12 , it is envisioned, is formed from welded steel bars and frame  14  from a sheet of planar steel. The front end of frame  14  has pivot attachments  15  which pivotably attach downward extensions from each side of the front end of the frame  14  to opposite aligned upward extensions from each side of the front end of chassis  12  by means of a pin inserted through mating holes to enable the frame  14  to pivot about the front end of the chassis. The rear end of frame  14  is free. This freedom permits the frame  14  to pivot with respect to chassis  12 . 
   Frame  14  has a front first shaft  14 A and an adjacent front second shaft  14 B. First shaft  14 A extends across the front end of a frame-attached platform through ball bearings, not shown, in opposing holes in downward extensions from opposite sides. Front first shaft  14 A has a rubber roller  12 A 1  over that portion of the shaft which is within the limits of frame  14 . Rubber roller  12 A 1  is keyed to first shaft  14 A. Shaft  14 A has a first gear  14 A 2  attached to one end. Second shaft  14 B extends through ball bearings in a gearbox cover, and the shaft  14 B protrudes to the outside of the frame  14 . Second front shaft  14 B has a second gear  14 B 2  attached to the protruding end such that the gears,  14 A 2  and  14 B 2 , intermesh. A larger third gear  14 B 3  is attached to the end of second front shaft  14 B opposite to second gear  14 B 2 . A third rear shaft  14 C extends across the rear end of frame  14  through opposing holes in downward extensions from opposite sides at the rear of the platform. Third rear shaft  14 C has a rubber roller  14 C 1  over that portion of the shaft  14 C which is within the limits of the platform. 
   A plastic planar platen  14 D overlies the upper surface of frame  14 . A treadmill belt  14 E is attached around rubber rollers  12 A 1  and  14 C 1  with the inner portion adjacent to the upper surface of platen  14 D. Platen  14 D minimizes friction between treadmill belt  14 E and frame  14 . The above apparatus provides a means of transferring force exerted on treadmill belt  14 E to third gear  14 B 3 . 
   A rear axle  12 A is pivotably mounted across the rear of chassis  12  through holes in opposed downward projections from the rear of the chassis  12 . A number of different sized sprockets  13 A, arranged in successive sizes, are attached to the end of rear axle  12 A essentially aligned with second gear  14 B 3  on the end of second front shaft  14 B. Sprockets  13 A are part of a bicycle type derailleur gear changer. A chain  12 AC 2  connects sprockets  13 A to third gear  14 B 3 . Derailleur  12 A 3  is attached to chain  12 AC 2  between sprockets  13 A and third gear  14 B 3  arranged such that the derailleur can move the chain  12 A 2  from sprocket to sprocket and change the gear ratio. A control cable  12 A 5  extends from derailleur mechanism  12 A 3  to a control lever  12 A 6  for operator control of the derailleur  12 A 3 . Rear wheels  12 C are attached to opposite ends of rear axle  12 A. This arrangement effects transfer of power from third gear  14 B 3  to rear axle  12 A via sprockets  13 A and drives the attached rear wheels  12 C forward when the upper run of treadmill belt  14 E is moved rearward by an operator. The arrangement also provides a means to change the treadmill gear ratio. 
   A clutch assembly  17  is mounted to a rear axle assembly and enables the operator to disengage the drive train from the treadmill assembly. This allows the operator to shift gears while the vehicle remains stationary or coasts. A clutch cable  17 A extends from clutch assembly  17  to a clutch lever  17 B for operator control of the clutch assembly  17 . 
   An automatic parking breaking apparatus is provided by apparatus which includes horizontal planar projections  14 F which extend rearward from opposite sides of frame  14 . Gas shocks  14 G are mounted between projections  14 F and chassis  12 . A brake cylinder  16  is mounted around rear axle  12 A. Projection  18  has a first downward portion and a second inward portion with an upward concave surface to better conform to an outer surface of brake cylinder  16 . Projection  18  is sized and arranged such that the second portion is below brake cylinder  16 . Gas shocks  14 G are arranged such that, with no operator standing on frame  14 , the shocks  14 G will force the platform upward such that the second portion of projection  18  will bear against cylinder  16  and provide an automatic brake by locking the rotation of rear axle  12 A attached to the cylinder. Suitable breaking material can be applied to either or both of the mating break surfaces for a more positive brake connection. 
   Two front wheels  20  are rotatably mounted on each side of the front of vehicle  10  through bearings (not shown). Each front wheel  20  has a disk brake  22 . The wheels  20 , disk brakes  22  and steering arms  24  are pivotably attached as a unit and arranged to pivot relative to a vertical axis from a bar  12 D attached to chassis  12 , which bar  12 D extends across the front of the chassis. Steering arms  24  are connected together by tie rods  26  arranged such that the pairs of steering arms  24  and wheels  20  will pivot together with the wheels remaining parallel to each other. A horizontally oriented steering hand bar  28  is attached to a cylindrically shaped vertical oriented steering tube assembly  30 . 
   Steering tube assembly  30  is pivotably connected to chassis  12  by being extended through a quick release collar  33  pivotably connected to support stanchions and then into keyed tube  33 A where it is secured in place by spring-loaded pins  33 B, one protruding through a hole on either side of the keyed tube  33 A. The support stanchions have ball joints  37  at the ends where they connect to the frame so that they may move upward or downward about a hinge point to permit steering tube assembly  30  to fold flat to the surface of the tread belt. 
   Steering tube assembly  30  is keyed to mate with keyed tube  33 A to take rotational stress off of spring-loaded pins  33 B. Keyed tube  33 A is pivotably connected to chassis  12  by being extended through a mating cylinder  32  with ball bearings (not shown) perpendicularly attached to chassis  12  near the center of the front. Steering tube assembly  30  is composed of an inner tube  30 A and an outer tube  30 B. Cylinder  32  is sized to allow rotation of steering rod  30  within the cylinder. An offset tab  34 , which is attached to the lower end of steering rod  30 , has an extension, the distal end thereof being pivotably attached to the end of each tie rod  26  through matching holes in the tie rod and extension. Tab  34  and tie rods  26  are secured by nuts and bolts. With this arrangement, moving steering bar  28  will cause front wheels  20  to train while remaining essentially parallel to one another to provide operator control of steering. A control cable  36  from both disk brakes  22  extends to a hand grip  38  mounted on steering bar  28  to provide operator braking control. Control cable  12 A 5  from derailleur  12 A 3  extends to control lever  12 A 6 . Control lever  12 A 6  is also mounted on steering bar  28  for operator gear changing control. 
   While various parts of this invention have been described with specific embodiments a number of other arrangements would occur to one skilled in the art. A tensioner could be added to the chain apparatus. The treadmill belt could be slotted for additional friction between the operator and the belt. A brush could be added to the belt apparatus to provide automatic cleaning of the belt surface. A variety of other arrangements which transfer power from the treadmill belt to the rear wheels could be employed. The breaking apparatus both for parking and during transit could be changed as long as they provided the necessary breaking functions. The steering apparatus could be one of a number known in the art for steering the front wheels while keeping the front wheels essentially parallel with each other. Since the above are just a few examples of the modifications and changes that are possible, that would readily occur to one skilled in the art, it is contemplated that the appended claims will cover any such modifications or embodiments as fall with the true scope of the invention.