Abstract:
The device is a portable tractor with attachments for powering skiers, skaters, snowboarders, and the like. It employs a rigid pole to deliver the thrust to a belt which converts the thrust to a pull on the skier&#39;s lower back, leaving the skier&#39;s arms, hands, legs and feet free to perform their usual skiing functions. The pole also provides leverage to turn the tractor so that it follows the skier&#39;s movements. The device provides controls over the tractor&#39;s engine to the skier&#39;s hands, or to other parts of the skier&#39;s body. The tractor has crawler treads bearing retractable cleats which automatically convert into sled runners so the skier can travel downhill pulling the tractor without dismounting the tractor. The tractor can be folded up and transported by backpack. Various attachments enable use of the tractor to power skates, sleds, snowboards and similar vehicles.

Description:
This application claims the benefit of Provisional Application 60/006,877 filed Nov. 17, 1995. 
    
    
     BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     MORE DETAILED BACKGROUND OF THE INVENTION 
     A key task in the development of power devices for skiers is to allow the skier maximum degrees of freedom to control the skis while delivering efficient driving thrust. 
     The shifting of a skier&#39;s weight and posture comprise a principal means of controlling skis. It follows that the skier&#39;s control task is complicated, and control likely is impaired, to the extent that the operational requirements of a driving device limit the skier&#39;s posture and balance on the skis or limit the motion of the skis themselves. Of course, any driving device, by adding a new force into the skier&#39;s balancing task, necessarily complicates that task to some degree. 
     Where the driving thrust is directly applied to the skis themselves, the connection between the skis and the tractor necessarily limits the degrees of freedom of the skis, to the detriment of control. There is, of course, an advantage to driving the skis directly because this can reduce the stress on the skier&#39;s legs which otherwise are required to transmit the power to drive the skis uphill. The instant invention avoids direct drive on the skis, thereby leaving greater freedom of movement to the skis and greater potential control of the skis to the skier, but at the price of some additional stress on the skier&#39;s legs to transmit the power to the skis. 
     Where the driving thrust is applied to the body of the skier, that necessarily limits the degrees of freedom in the skier&#39;s posture and muscular control. This problem can be better illustrated by reference to some existing devices to power skiers. 
     For example, in the device of Mehne, U.S. Pat. No. 3,826,323, the driving thrust is delivered through rigid frame against the skier&#39;s buttocks and requires that the skier shift some body weight away from the skis onto the driving tractor. These requirements tend to limit or confine the skier&#39;s posture on the skis, thus reducing the degrees of freedom available to the skier&#39;s body to control the skis. 
     Mehne&#39;s device patented in 1974 shows an apparently rigid frame  7  which delivers thrust from a tracked tractor to the buttocks of the skier when the skier rests a portion, but not all, of his body weight onto frame  7 . Frame  7 , when used to drive the skier, is secured in position on the skier&#39;s buttocks by a belt  12 . Frame  7  also is adapted to serve as a backpacking frame to carry the tractor when not in use. Mehne discloses that the proportion of the skier&#39;s weight which rests upon the tractor, through frame  7 , is critical to efficient operation of the tractor. This is because the Mehne device alone, without some of the skier&#39;s weight, lacked sufficient traction. However, Mehne discloses that if the skier rests too much body weight on the Mehne device it requires an excessively heavy engine to achieve adequate speed. Mehne&#39;s device also includes straps  27  and  28  which attach the skier&#39;s ankles or boots to the tractor, for the purpose of limiting the separation between the skis and the tractor. Mehne&#39;s straps further limit the skier&#39;s freedom of movement. 
     In Allisio&#39;s device, as depicted in U.S. Pat. No. 4,519,470, the skier is delivered dual power thrust from both (A) the driven skis and also (B) rigid “ski sticks” (which apparently are the skier&#39;s own ski poles) that extend from the tractor between the skier&#39;s legs and bear a “seat”  35  which drives against the back of the skier&#39;s thighs. Allisio&#39;s “ski sticks”  37  are clipped together with a handle  4 , and the tips of the ski sticks are inserted into a plate  39  to form a “rigid connection” to the crawler tractor. At the same time the tractor also drives the skis directly through plates  16  on the rear end of the skis which connect to plates  19  on an ‘articulated connection’  15  to the tractor. It is apparent that adjusting these dual power thrusts on both the skier&#39;s thighs and on the skis may be critical to the skier&#39;s own balance, hence to control of the skis. It also appears that balancing these dual thrusts on the skier&#39;s thighs and the skis must to some extent dictate, and confine, the skier&#39;s posture on the skis. The skier&#39;s balancing task is further complicated by Allisio&#39;s disclosure that “a large part of the skier&#39;s weight acts on the self-propelled unit”. Allisio Specification, Column 1, line 25. It appears, therefore, not only that the adjustment of the seat  35 , relative to the tractor&#39;s driving connection to the skis, may be critical, but also that the skier&#39;s balancing of body weight between the seat  35  and the skier&#39;s feet on the skis may be critical. 
     In the Allisio device, the use of dual thrusts on both the skier&#39;Is thighs and on the skis may be viewed as disadvantageous to the extent that it complicates a skier&#39;s balance on the skis by confining the skier&#39;s posture and compelling weight-shifting, while simultaneously also limiting the degrees of freedom of the skis themselves by the power thrust through a connection to the ski tails. In addition, the Allisio device requires use of the skier&#39;s hands on the handle  4  and deprives the skier of the normal uses of the hands and ski poles for balance and control. 
     RELATED ART 
     U.S. PATENT DOCUMENTS. 
     A variety of tractors and propulsion devices for skis exists. 
     One functional distinction in the prior art is between those tractors which attach to and directly drive the skis and those which drive the body of the skier rather than the skis. 
     Some of the many examples of devices which directly drive the skis are Van Voorhees, U.S. Pat. No. 2,625,229, issued Jan. 13, 1953; Gremeret, U.S. Pat. No. 3,568,787, issued Mar. 9, 1971; Thompson, U.S. Pat. No. 3,645,348, issued Feb. 29, 1972; Thompson, U.S. Pat. No. 3,710,881, issued Jan. 16, 1973; McLoed, U.S. Pat. No. 3,809,173, issued May 7, 1974; Husted, U. S. Patent No. 3,853,192, issued Dec. 10, 1974; Husted, U.S. Pat. No. 3,964,560, issued Jun. 22, 1976; and Husted, U.S. Pat. No. 4,035,035, issued Jul. 12, 1977. 
     A device which drives the body of the skier, rather than the skis, is Mehne, U.S. Pat. No. 3,826,323, issued Jul. 30, 1974. The device of Allisio, U.S. Pat. No. 4,519,470, issued May 28, 1985, drives both the body of the skier and the skis. 
     A control device for powered skis is disclosed by Shiber, U.S. Pat. No. 3,996,010, issued Jun. 29, 1976. 
     The foregoing list is intended as illustrative, not exhaustive. 
     SUMMARY OF THE INVENTION 
     The invention has several aspects. One aspect is comprised of a rigid pole and belt configured to deliver power to the body of a skier to move the skier uphill, while leaving the skier&#39;s hands free to use ski poles and the skier&#39;s feet and legs free to balance upon and control the skis. Modifications adapt the invention to power persons riding on snow boards, skates, skate boards, or equivalent devices. 
     Another aspect of the invention comprises hinged cleats on a crawler-type tractor, adapted to power skiers. The cleats engage the travelling surface when the tractor&#39;s forward motion is driven by the rotation of the treads, but the cleats fold back, disengage from the travelling surface and form a sliding surface when the tractor&#39;s forward motion is faster than the rotation of the treads. Thus, the cleats automatically engage when the treads are the driving force, as when travelling uphill or on the flat, but disengage, turning the tractor treads into sled runners so that the skier can ski downhill pulling the tractor. The cleats of the invention thus eliminate the necessity to dismount the tractor, fold it into a backpack, and carry it down slope on the skier&#39;s back. Of course, the tractor still can be folded into a backpack and carried when desired. A similar mechanism which allows a wheeled tractor&#39;s driving wheels to ‘freewheel’ downhill can be employed where a wheeled tractor is used to power a person on skates. 
     OBJECTIVES, FEATURES AND ADVANTAGES OF THE INVENTION 
     An objective of the invention is to deliver motive power from a tractor to a skier while leaving the skier&#39;s hands, feet and legs with freedom to control the skier&#39;s balance and the skis. It is a feature of the invention that it delivers motive power to a skier from a tractor without any connections delivering motive power from the tractor directly to the skis, or to the skier&#39;s hands, feet or legs, thus leaving them more available for use to control the skier&#39;s balance and the skis. An advantage of the instant invention is that it allows the skier to use hands and ski poles, though at least one hand does have the additional task of manipulating tractor engine controls supplied to the skier&#39;s hand(s) through one or more flexible wires or cables. In principle, the tractor also could be radio controlled through controls supplied to the skier&#39;s hands. 
     A further challenge in delivering motive power to a skier&#39;s body is to transmit the motive force to propel the body while minimizing interference with the skier&#39;s normal skiing motions. Among other things, this tends to retain a larger degree of the sense of ‘free’ skiing, as distinguished from passively riding a powered vehicle. The instant invention transmits a single pulling force through a flexible, rotatable connection between the driving pole and the focal point of the pulling force on the skier&#39;s body. This permits the skier some ability to rotate or swivel about the connection to the power pole. The focus of the pulling force on the skier&#39;s body preferably is at the lower back, waist or buttocks, which places the force pulling force near the skier&#39;s hip joints and near the center of gravity of the skier&#39;s body. Delivery of the pulling force at this point leaves the skier&#39;s body relatively free to rotate about the focal point of the pulling force, in a plane perpendicular to the pulling force. The flexible, rotatable connection of the pulling force to the skier&#39;s body also permits some freedom to swing from side to side, or up and down, relative to the rigid pole which delivers the pulling force. The focal point of the pulling force can be adjusted to some extent on the skier&#39;s body, according to the skier&#39;s preference. Thus, the instant invention allows the skier relatively great freedom to engage in many ‘normal’ or habitual skiing motions with minimal interference from the pulling force imposed at or near the skier&#39;s hips or waist. 
     A further feature of the invention is that the rigid pole or other structure which delivers the driving thrust from the tractor to the connection to the skier&#39;s belt also acts as a lever which transmits the skier&#39;s turning motions to the front of the tractor. The pole thus urges the tractor to turn following the skier&#39;s hips. In effect, the tractor tends to simply follow the skier under the urging of the rigid pole. This turning control over the tractor is particularly enhanced in the configuration where the skier is astride the rigid pole so that the skier&#39;s thighs apply the turning force directly to the pole. Of course, this turning leverage can be readily increased by simply increasing the length of the pole, and the length of the pole can be made adjustable to give a skier individualized control over the amount of this leverage. 
     Another challenge in the development of powered skiing is to keep the driving tractor and the thrust delivery system sufficiently light and compact to be comfortably portable. Note that both the Mehne and Allisio devices are designed to fold onto backpacking frames to be carried by the skier. Both Mehne and Allisio depict the skier as carrying the tractor in a backpack when skiing down hill. It is desirable to avoid having to pack up the tractor unit and carry it downhill, and particularly so where travel is overland, with a mixture of uphill and downhill terrain. 
     An objective of the invention is to enable the skier to travel downhill, as well as uphill, without dismounting the driving connection between the skier and the tractor. A feature of one species of the invention is hinged cleats on the treads of a crawler tractor, such that the cleats disengage from the travelling surface and become sled runners when the tractor&#39;s forward motion is faster relative to the travelling surface than is the rotation of the tractor&#39;s treads. The advantage is that the cleats engage the travelling surface when driven under the power of the tractor in uphill or flat conditions, but the cleats disengage so that the tractor treads turn into sled runners when travelling downhill. The skier has influence over this cleat-disengagement effect because the tractor has a centrifugal clutch. Engine controls are supplied to the skier&#39;s hand(s) through one or more cables so the skier can disengage the centrifugal clutch by reducing the engine speed, thereby slowing the tractor tread revolution and allowing the tractor&#39;s forward speed to retract the cleats. This allows the skier to ski downhill pulling the tractor on sled runners rather than having to dismount the tractor and carry it downhill. 
     Another species of the current invention connects the engine controls to the skier&#39;s shoulders or other upper body so that the skier can activate the engine controls by leaning away from or towards the tractor. For example, the controls can be set up so that if the skier leans or crouches forward, away from the tractor, the engine throttle is advanced, speeding up the engine, while if the skier leans back, or stands up out of the crouch, the engine is slowed. This provides the skier with hands-free control of the engine speed. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     One aspect of the invention is an improved thrust-delivery system for powering skiers, which allows a high degree of freedom to the skier. The sole thrust is delivered through a rigid drive pole  8  which passes between the skier&#39;s legs and which is flexibly, rotatably connected at the skier&#39;s front to a belt worn about the skier&#39;s waist or lower back. The skier thus is drawn forward by the pull of the guide pole through the flexible, rotatable connection against the belt, with the pole being pushed by a tractor from behind the skier. The belt, when combined with harness straps over the shoulders, can be adjusted to deliver the pull from the drive pole over a wide range of positions on the skier&#39;s body, from thighs up through mid-back. The belt usually is adjusted to focus the pull on the skier&#39;s waist or lower back, thus leaving greater degrees of freedom to maneuver hips, legs and feet to control the skis. The skier&#39;s hands remain free to use ski poles, while controls for the tractor are provided to the skier&#39;s hands through flexible wires or cables. There is no direct connection between the driving tractor and the skis so that control of the skis comes entirely through the skier&#39;s feet. This configuration leaves more degrees of freedom for the skier to shift his weight and balance to control the skis and to employ ski poles. Persons knowledgeable in the art will perceive that the belt harness can be adjusted by the skier to the best lancing posture for the particular skier&#39;s needs and skiing style. The length of the drive pole, and the shape of the tab which connects the pole to the belt worn by the skier, also can be adjusted, thereby altering the vector of the force delivered by the drive pole to the belt. This adjustment is significant because angle of the drive pole relative to the ground determines, in part, the size of the vertical component of the force which the drive pole imposes downward on the front of the driving tractor. This downward component of force is important to the traction and efficiency of the driving tractor. Note, for example, that both the Mehne and Allisio devices require such a downward component of force on the driving tractor for it to perform properly. Persons having skill in the art will perceive that the drive pole passing between the skier&#39;s legs as depicted in the drawings could be replaced by a structure which curves around one or both of the skier&#39;s sides, rather than between the skier&#39;s legs, to produce equivalent results. 
     In another aspect of the invention, the cleats on the tractor&#39;s driving treads are hinged so that when the tractor is not moving forward faster than the treads are revolving, the cleats grip into the snow. However, when the tractor is moving forward faster than the treads are revolving the tread cleats automatically rotate backwards, retracting to convert the treads to a smooth sliding surface. Thus, when the tractor is moving forward faster than its own treads are revolving, the tractor treads act as sled runners. With this improvement, the tractor can be towed downhill by the skier and thus does not need to be dismounted, packed up, and carried downhill on the skier&#39;s back. The instant invention also can be folded into a backpack and carried on the skier&#39;s back when desired. Alternatively, the tractor&#39;s retractable cleats permit the skier and the deployed tractor to be towed by some other power source which moves faster than the tractor treads revolve under the tractor&#39;s own power. 
     In other aspects of the instant invention, it can be modified to power skaters, snow-boarders, and sleds as depicted in the drawings. In one version, the tractor is equipped with a lightweight, inflatable sled which can be carried in a pack and deployed as needed. The user thus could employ the tractor in an emergency to transport an injured person, or could transport other objects. 
     Of course, the energy source for the tractor&#39;s engine could be combustion, electric batteries, or other energy source. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a skier being propelled up a hill by the power-driver unit, while wearing a belt-harness connecting system that can also be used to back carry the unit on the down hill run. FIG. 2 is a perspective view of the power-driver unit in a vertical position with the power pole extended. 
     FIG. 2A is a perspective view of the power-driver unit with the power pole being folded into a pack position. 
     FIG. 3 is a perspective view of a skier skiing down hill with the power-driver unit strapped to his back. 
     FIG. 4 is a side view of the power-drive unit connected to the power pole attached to the users belt-harness and showing the throttle/kill switched attachment at the ski pole. 
     FIG. 5 is a longitudinal cross section view of the gas power-driver unit and the folding snow cleat system. 
     FIG. 6 is a perspective detail view of the drive belt and folding snow cleat. 
     FIG. 6A is a cross section detail view of snow cleat positioned on the top side of the belt run over open top of lower frame. 
     FIG. 6B is a cross section detail view of the snow cleat positioned on the bottom side of the belt run, under closed lower frame, while in the power mode. 
     FIG. 6C is a cross section detail view of the snow cleat positioned on the bottom side of the belt run in a open non-powered slide mode. 
     FIG. 7 is a perspective view of a roll-up inflatable sled connected to a power-driver unit. 
     FIG. 8 is a parcel top view of the roll-sled showing control and connecting means to the power unit. 
     FIG. 9 is a longitudinal cross section view of a roll-up inflatable sled and a partial side view of the power-driver unit and control bar. 
     FIG. 9A is a side view of inflatable sled deflated and rolled into a storage mode. 
     FIG. 10 is a perspective view of a sled gurney connected to the power-driver system 
     FIG. 11 is a perspective view of a snow bike connected to a power-driver system. 
     FIG. 12 is a side view of power unit attached to a snow board, showing the user&#39;s riding/control position. 
     FIG. 12A is a top view of the snow board control attachment system showing range of movement. 
     FIG. 13 is a longitudinal cross section side view of an electric power-driver unit. 
     FIG. 13A is a perspective view of the electrical power-driver unit with it&#39;s battery or fuel cell in the extended removal/replacement mode. 
     FIG. 14 is a cut away longitudinal side view of a small power driver, control-connecting rod and throttle system for skating unit. 
     FIG. 14A is a top view of the small skating power driver control system. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Referring now to FIGS. 1,  2 ,  2 A,  3 ,  4  and,  5 , showing a portable drive unit  1  powered by a two cycle gasoline engine  2  which is mounted on a upper frame  3 , with a lower frame  4  supporting two snow tracks  5  and  6 . Power is transferred from the engine to the tracks through a centrifugal clutch  7 A by a chain drive system  7 . The skier is pulled forward by power pole  8  which is attached to the lower frame by fork  9  having locking pivot points  10  and  11 . Power pole length can be adjusted or the pole can be dismantled by loosening adjustment clamp  12 . The skier rides astride the power pole over the padded saddle  15  with his belt harness  13  attached to the end of the power pole at eyelet  14  with a quick release clip  16 . The drive unit is controlled by cable  17  which runs from the engine through the power pole to a hand controlled throttle  18  having a kill switch  19  located at the top ski pole  20 . 
     FIG. 1 shows the portable power unit  1  in uphill driving configuration. 
     FIG. 2 shows the portable power  1  unit in a vertical position with power pole  8  extended. 
     FIG. 2A shows the guide pole  8  being folded at pivot points  10  and  11  and pole shortened at adjustment clamp  12  to fold into the packing position. 
     FIG. 3 shows the system in a back packing configuration attached to belt-harness  13 . 
     FIG. 4 shows the system in a fully extended operation configuration. 
     FIG. 5 is a longitude section view of the power unit showing the interior of the driver system. 
     Referring to FIGS. 5,  6 ,  6 A,  6 B and,  6 C, the chain drive system  7  (FIG. 5) having a centrifugal clutch  7 A, drives tracks  5  and  6 . Each track consisting of a drive belt  21  and a series of hinging snow cleats  22 . When under power belt  21  rotates in a clockwise direction moving the hinging snow cleats  22  around frame  4 , as it moves from the open top of frame  4  it will contact the closed frame bottom at point  4 A which will push against stop/support  27  causing the bite leaf  26  to rotate on axis pin  25  to an extended position (FIG. 6B) catching the snow and power the unit forward (power mode). As long as bite leaf  26  is under frame  4  (in the power mode), hinge stop  27  will bear on the bottom of frame  4  to support the bite leaf  26  in an extend position pushing against the snow. As the belt rotation reaches point  4 B there is no longer support for hinge stop  27  and the pressure of the snow will force the stop through belt opening  28  and the bite leaf will rotate to a closed position. This allows folded cleat  22  to pass under frame section  3  (FIG. 6A.) . When the system is not under power and belt  21  is no longer moving (FIG. 6A) the forward momentum of the power unit  1  over the snow  30  will force bite leaf  26  to swing to an open position allowing the snow  30  to move uninhibited under cleats  22 , putting the system into a sled mode. When in a sled mode, a skier can ski down a slope in a normal fashion controlling the power unit&#39;s direction with the power pole  8  with no resistance from the snow cleats  22 . When the power is reapplied the rotation of belt  21  over the snow  30  forces the bite leaf  26  to return to an extended supported position pushing the system forward in a power mode (FIG. 6B) . The skier can then power up the next slope. 
     FIG. 6 perspective detail of typical section of drive belt  21  showing a hinging snow cleat  22  attached to belt by leaf  24  having axis pin  25  attached to bite leaf  26  having support stops  27 , which can pass through belt  21  at slots  28 . 
     FIG. 6A longitudinal section detail of hinging snow cleat  22  as it passes over the top of frame  4 , stops  27  having no support causes bite leaf  26  to fold under upper frame  3  through slot  28  in belt  21  (FIG.  5 ). 
     FIG. 6B longitudinal section detail of hinging snow cleat  22  as it passes under frame  4 , in a power mode, stop  27  holds bite leaf  26  in an extended mode pushing against snow  30 . 
     FIG. 6C longitudinal section view of hinging snow cleat  22  in a non-powered mode at the bottom of frame  3 , snow  30  has forced bite leaf to fold open in a slide mode. 
     Referring now to FIGS.  7 , 8 , 9  and,  9 -A shows a light weight roll up sled  32  attached and powered by portable power-driver  1 (FIG.  7 ). Sled  32  has a sleep bag like cover  33  with a sticky closure flap  34 , the user would be in the sleeping bag setting on the inflatable cushion  35  (FIG. 9A) that is attached to the flexible plastic base  36  which is the sled bottom. He would stop the sled with brake  31  and controlling his direction with a guide bar  37  (FIG. 9B) which is attached to the guide fork  9 , which will turn the power-driver  1  about pivot connection point  38 . The engine is controlled by a hand throttle  18  and kill switch  19  which is attached to the end of control bar  37 . By deflating cushion  35  bag  33 , cushion  35  and, base  36  would roll up into compact carrier  39  (FIG. 9C) that would fit into the trunk of a car. 
     FIG. 7 perspective view of a roll-up inflatable sled  32  and power-driver unit  1 . 
     FIG. 8 a partial top view showing the relationship of guide bar  37 , fork  9  and pivot connector  38  to power unit  1  and sled  32 . 
     FIG. 9 longitudinal cross section view of roll-up sled  32  and, a partial side view of the power unit and control bar  37 . 
     FIG. 9A side view of inflatable sled  32  deflated and rolled into a carry/storage mode. 
     FIG. 10 a perspective view of a folding sled gurney  40 , powered by the power-driver unit  1  consisting of a folding stretcher  41  which would attach to skis bindings with shoe bracket  42  and clamps  43 . The system would be controlled by a user standing on top of the power unit frame  3  at with his feet at points  3 A and  3 B. By moving handle bars  44  user could turn gurney about pivot connection point  38 , and control his forward speed with the hand throttle  18  and, kill switch  19 . 
     FIG. 11 is a perspective view of a snow bike  50  riding on and attached to power-driver  1  by fork  9  having a quick disconnect clamp  51  that connects to bike frame  52  which has an adjustable passenger seat  53 , and handle bars  44 . The user controls his direction by turning the handle bars  44  which are connected to shaft  54  that is attached to shock absorber  55  which houses and is connected to shaft  56  that attaches to horizontal swivel point  57  that is connected to guide ski  58 . The user setting on seat  53  astride frame  52  with feet placed on foot bars  59  and would control his forward speed with throttle  18  and kill switch  19 . 
     FIG. 12 is a side view of power driver  1  attached to a snow board  60  by means of a pivot/connector  38 . The user stands with one foot in bindings  61  on the snow board and the other foot in binding  62  centered over pivot/connector  38  and attached to the power unit  1 . Direction is controlled by the user twisting his front foot at binding  61 , engine is controlled with a hand held throttle  18  and kill switch  19  connected by cable  17 . 
     FIG. 12A top view of snow board  60  showing placement of bindings  61 ,  62  and, the range of the snow board movement about pivot point  38  as  60 A and  60 B. 
     FIG. 13 is a side view of a power driver  63  equipped with an electric motor  64  powered with a quick replacement battery or fuel cell  65 . System would be used in areas where air quality and noise would present a problem for a gasoline internal combustion system. 
     FIG. 13A perspective view of electric power driver  63  with battery of fuel cell extended for replacement. 
     FIG. 14 is a side view showing a smaller two cycle centrifugal clutch engine  66  that is attached to power pole  8  driving a wheel  67  by means of chain or friction system  68 . The user stands astride the end of guide pole  8  having a padded seat  69  with skates on, and attaches belt harness  13  to eyelet  15  with a quick disconnect clip. Skater controls his direction by skating in a normal fashion and his speed by leaning forward at the shoulders to apply pressure to throttle cable  70 . This type of control system allows the skater to use both of his hands to hold a hockey stick or to pass a ball. The wheel  67  could be studded with spikes for ice skating. If the wheel  67  should be stalled or be lifted from the ice a pressure switch returns the engine to idle. 
     FIG. 14A is a top view showing the configuration of seat  69  engine  66  and wheel  67 .