Patent Abstract:
A steering and transmission mechanism interconnects the front and rear wheels of an in-line vehicle which includes rigid steering members or links operable by manual control for selectively determining rear wheel positioning from a normal turn or straight position to a crab position. Each member has adjacent ends selectively coupled together by a lock-arm movable in response to a manual control to change rear wheel positions. The steering members are slidably carried on a shifter housing and a resilient device is employed for returning steering from the crab position to the normal steering position.

Full Description:
Priority claimed on Ser. No. 60/542,356 filed Feb. 9, 2004 pending. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to the field of vehicle steering, and more particularly to a steering transmission mechanism interconnecting front and rear wheels so as to maneuver the vehicle with respect to a longitudinal axis in an arcuate path, a linear path or in a linear angular path. 
   2. Brief Description of the Prior Art 
   Maneuverability of a conventional in-line wheeled vehicle, such as a scooter, is limited due to the fact that the front and rear wheels track along a common path that restricts maneuvering. In some instances, maneuverability is increased by permitting rotation or pivoting of the rear wheel to follow the front wheel so that a curvilinear path is followed which allows for more turning freedom and a shorter turning radius. Such examples are disclosed in U.S. Pat. No. 5,954,349, No. 4,799,702, and No. 4,555,122. 
   However, problems and difficulties have been encountered with these conventional vehicles, which stem largely from the fact that all the interconnecting mechanisms or transmission means between the front and rear wheels are directly connected to and are supported on the vehicle frame. The prior mechanisms rely on cable and pulley arrangements which have a tendency to stretch creating slack or “play” during structural flexing. In other instances, strings, complicated flexible linkages and rider body weight balancing techniques are employed to effect rear wheel pivoting so as to track with the front wheel. Still others, such as disclosed in U.S. Pat. No. 3,620,547 (FIG. 6) permit both turning of the front and rear wheels so as to track along a linear or curvilinear path as well as allowing the wheels to track in parallel in angular relation to the longitudinal axis of the frame wherein such a maneuver gains “crab” maneuvering. Again, it is the shifting of the rider or driver&#39;s weight which achieves the pivoting of the rear wheel to effect such maneuvering. 
   In none of the above reference disclosures is there provision of a mechanism not supported or directly fastened to the frame that employs a rigid mechanism to effect shift or change from turn-steering to crab-steering by manual switch-over control. 
   Therefore, a long-standing need has existed to provide a steering and transmission assembly for a vehicle, such as an in-line scooter, that is rigidly connected between the front and rear wheels and operable to alternately cause the rear wheel to track the front wheel in a curvilinear path or to cause the rear wheel to pivot parallel to the front wheel where both wheels are in an angular “crab” path with respect to the center line of the vehicle and wherein the assembly is supported on the front and rear wheel assembly without connection or support on the frame of the vehicle. 
   SUMMARY OF THE INVENTION 
   Accordingly, the above problems and difficulties are avoided by the present invention which provides a novel steering and transmission means interconnecting the front and rear wheels of an in-line vehicle which includes rigid steering members operable by manual control for selectively determining rear wheel positioning. Each member has adjacent ends selectively coupled together by a lock-arm movable in response to a manual control to change wheel positions. The steering members are slidably carried on a shifter housing and resilient means are employed for returning steering from a crab position to a normal steering position. 
   In one form, a first steering member is employed for normal turn-steering and has one end connected to a pivotal rear wheel fork. A second member is for crab-steering having one end thereof attached to the opposite side of the rear fork. A movable shifter lock-arm extends between the free ends of the first and second members for selectively positioning the rear wheel to either normal or crab steering positions. 
   Therefore, it is among the primary objects of the present invention to provide a novel vehicle, such as a scooter, with alternate turn-steering and crab-steering wheel positions, having a manually operated shift mechanism for controlling the orientation of the rear wheel. 
   Another object of the present invention is to provide a shifting and transmission mechanism for a two-wheel push scooter capable of manually converting turn-steering to crab-steering while the user is riding the scooter by using a hand control. 
   Still a further object of the invention is to provide a steering and transmission mechanism for the front and rear wheels of a vehicle wherein there are no attached points or support of the steering linkage or shifter unit to the main framework of the scooter. 
   Yet another object of the present invention is to provide a vehicle, such as a scooter, which includes a folding handlebar as well as a front and rear wheel shifting and transmission assembly which do not interfere with the function of either folding or steering operations. 
   A further object resides in providing a scooter which is capable of two-wheel steering, wherein each wheel is turned in opposite directions in order to cause a turning motion but which can also be shifted so both wheels can be steered with the wheels aligned in parallel with each other that permits the scooter to travel sideways. 
   A further object of the present invention is to provide a steering and transmission means for interconnecting the front and rear wheels of a vehicle so that the wheels may be pivoted in an angular orientation with respect to the center line or longitudinal axis of the scooter in order to effect sideways travel of the scooter. 
   Another object resides in a vehicle having two-wheel steering in which each wheel is turned in opposite directions so as to cause a turning motion which alternately can be shifted so both wheels can be steering with the wheels aligned in parallel with each other. 
   A feature resides in providing a manually operated shifting means for selecting rear wheel position for normal turn-steering or crab-steering and for shifting a two-wheel push scooter, or the like, from turn-steering to crab-steering while the operator is riding and back again by employing a hand control. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood with reference to the following description, taken in connection with the accompanying drawings in which: 
       FIG. 1  is a side-elevational view illustrating an in-line vehicle, such as a scooter, employing the wheel shifter and transmission means incorporating the present invention; 
       FIG. 2  is an enlarged perspective view showing the front and rear wheels of the in-line vehicle wherein the pivotal rear wheel is pivotal with respect to the longitudinal axis of the vehicle frame; 
       FIG. 3  is a diagrammatic top plan view illustrating pivoting of the rear wheel to be in a curvilinear path tracking the front wheel with respect to the longitudinal axis of the frame; 
       FIG. 4  is a view, similar to the view of  FIG. 3 , illustrating the rear wheel in parallel with the front wheel to permit angular travel with respect to the longitudinal axis of the frame performing a crab-steering procedure; 
       FIG. 5  is a bottom sectional view of the shifting and transmission means incorporating the present invention as used on the vehicle shown in  FIG. 2  in the direction of arrows  5 - 5  wherein the front and rear wheels follow a curvilinear path as shown in  FIG. 3 ; 
       FIG. 6  is a bottom sectional view, similar to the view of  FIG. 5 , illustrating the front and rear wheels in position to achieve angular or crab-steering as illustrated in  FIG. 4 ; and 
       FIG. 7  is a transverse cross-sectional view of the shift and transmission means shown in  FIG. 5 , as taken in the direction of arrows  7 - 7  thereof. 
   

   DESCRIPTION OF PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , a novel steering and transmission means for the front and rear wheels of an in-line vehicle is indicated in the general direction of arrow  10 . Although the present invention relates to other types of vehicles, the present invention is illustrated in connection with an in-line scooter having a frame  11  on which the operator or driver of the scooter is supported. The front end of the scooter includes a front wheel  12  which is carried on a fork  13  which, in turn, is carried on a fixture  14  at the end of an elongated handle  15  which is collapsible. The handle includes an elongated tube for receiving an upper portion  16  that is adjusted for height and secured in position by a clamp  17 . The upper end of portion  16  of the handle  15  includes handlebars  18  which supports manual lever control  20 . The handle  15  including front fork  13  and front wheel  12  rotates with respect to the fixture  14  and it can be seen that the fixture  14  is attached to the frame  11  by a brace  21 . The brace is further supported on the frame by a cam-lock device  22  which includes a locking handle  23 . Therefore, it can be seen that the handle  15  may be shortened or lengthened by moving the portion  16  in and out of the tube in which it is mounted and that the handle can be folded towards the rear of the frame  11  by loosening the cam-lock  22  via handle  23  so that the brace  21  will travel through the yoke of the cam-lock device. So, it can be seen that the lever handle  20  for the shift mechanism is connected to a shift and transmission means under the frame  11  by a cable  24 . Furthermore, when the handle  15  has been adjusted for height and securely locked in upright position, the front wheel  12  can be pivoted with respect to fixture  14  by twisting or turning handle  18  as in the direction of the double arrows shown. 
   The vehicle  10  further includes a rear wheel  25  that is rotatably carried on a rear fork  26 . Fork  26  is rotatably carried on a rear fixture  27  that is attached to the rear of the frame  11  by a rear brace  28 . A brake  30  is provided whereby the operator of the vehicle can depress the brake so that friction is applied to the rear wheel  25  as is the customary practice. 
   The wheels as illustrated in  FIG. 1  are in an in-line arrangement where the rear wheel  25  tracks the same path as the front wheel  12 . The front and rear wheels are illustrated lying on the central longitudinal axis of the frame  11  so that the vehicle will progress in a straight-forward line of travel. However, when it is desired to change position so that the vehicle travels in a turn position or to a crab position, linkage is provided such as a turn-steering link  31  and a crab-steering link  32 . Also, the steering and shifting means within the frame  11  further includes a rigid steering rod  33  that is connected to the front fork  13 . 
   Referring now in detail to  FIG. 2 , it can be seen that the rear wheel  25  can be rotated or pivoted in alternate directions as shown in broken and solid lines. Each of the respective steering links  31  and  32  are coupled to flanges outwardly projecting from the fork  26  by means of a lug  35  connected to a post or pin  36 . The same construction is included for the connection of the free end of link  31  with the opposite side of the fork  26 . Also, the steering rod  33  is connected to an outwardly projecting flange on the front fork  13  by means of a lug  37  and pin  38 . The links  31  and  32  as well as rod  33  are connected to a shift and transmission means carried in a housing  40  underneath the frame  11 . It is to be understood that there is no connection between housing  40  and the frame  11  which is a major feature of the present invention. It can be seen that the free ends of links  31  and  32  are exposed beyond the rear of frame  11  while the free end of steering rod  33  is exposed from the front end of frame  11 . The links and rod are inter-connected within the housing  40  and will be described in detail later. 
   Referring now to  FIG. 3 , the rear wheel  25  may be pivoted or rotated to a position with respect to the longitudinal axis of the frame  11  by means of the steering arrangement so that the rear wheel will track the front wheel  12  in a curvilinear path for turning purposes. This positioning of the rear wheel  25  is noted as the turn position and the travel of the rear wheel will follow the arcuate or curvilinear path of the front wheel  12 . 
   With respect to  FIG. 4 , it can be seen that the rear wheel  25  can be pivoted or rotated to an angular position with respect to the central longitudinal axis of housing  40 . In this position, the rear wheel  25  is parallel with respect to the front wheel  12  and permits a crab steering so that the vehicle will progress in an angular orientation with respect to the central longitudinal axis of the housing  40 . 
   Therefore, in the layout shown in  FIG. 3 , as the front wheel is turned, the rear wheel turns in the opposite direction which causes the vehicle to move in a normal turning fashion. However, in the layout shown in  FIG. 4 , as the front wheel is turned, the rear wheel turns in the same direction as the front wheel which causes the scooter to crab sideways. 
   Referring now in detail to  FIGS. 5 and 6 , the shifting and transmission means located beneath the vehicle frame  11  is illustrated. It can be seen that the housing  40  includes parallel channels  41  and  42  and that the turn-steering link  31  is in sliding position in channel  41  while the crab-steering link  32  resides in sliding condition in channel  42 . Roller bearings, such as bearing  43 , are carried on the links  31  and  32  for ease of movement within the channels. The shifter lock-arm  44  resides between the links  31  and  32  and include rollers on opposite ends of the arm  44  which selectively engage with either a notch  45  in link  31  or in a notch  46  in link  32 . As illustrated, in  FIG. 5 , the shift lock-arm  44  is engaged in engaged in notch  45  of link  31  so as to effect normal turn steering. To support the lock-arm  44 , a pair of swing-arms  47  and  48  have their opposite ends pivotally attached to the housing  40  on one end and to the lock-arm at their opposite ends. The lock-arm is normally biased into engagement with notch  45  in link  31  by means of a return spring  50  having its opposite ends connected to the housing  40  and to the arm  44  respectively. The end of shift cable  24  passes through the housing  40  and terminates at the end of a shift pull spring  52 . The end of spring  52  is attached to a retaining pin  53  carried on the swing arm  47 . Furthermore, it can be seen that the steering rod  33  is secured to the housing  40  so that as the front wheel is turned by the hand steering mechanism, the rod  33  will move a limited distance forward or a limited distance rearward depending on the direction of turn. Therefore, it can be seen that a solid load bearing path is from the wheel  25  through link  31  and the shift housing  40  to the rod  33  and the front wheel  12  when the shifting and transmission means is in the turn-steering position. 
   In the crab-steering position shown in  FIG. 6 , shift cable  24  has been retracted so that the swing arms  47  and  48  will cause the lock-arm  44  to move out of engagement with notch  45  in link  31  where upon the rear fork  26  rotates causing link  32  to be aligned with lock-arm  44  wherein the roller at the end of the arm will engage notch  46 . At this time, link  31  merely floats within channel  41  while a load bearing straight path is from the rear wheel  25  through link  32  into the frame  40  and hence to shift-rod  33  and wheel  12 . 
   With respect to operation, in  FIGS. 5 and 6  a shift and transmission means is illustrated that allows instant shifting from turn-steering to crab-steering. In normal turn-steering mode, when the vehicle or scooter handles (not shown) are turned, the front wheel turns causing fork  13  to move steering rod  33  in a fore and aft direction. This causes the shifter housing  40  to also move fore and aft. Since shifter lock-arm  44  is engaged into steering link  31 , the rear wheel fork  26  moves fore and aft causing the rear wheel to turn in the opposite direction of the front wheel, thereby causing the scooter to “turn” in a normal fashion. This action is possible because shifter lock-arm  44  is engaged only in slot  45  in steering-link  31  and is not engaged in the crab-steering link  32  which is left free-floating during normal steering. 
   To shift to crab-steering, the hand lever  20  on the handlebars  18  is pulled or activated which pulls shifter cable  24  and subsequently pulls on shifter spring  52  which causes the shifter lock-arm  44  to try to retract from turn-steering link  31 . Unless front and rear wheels are perfectly aligned in a direction parallel with the scooter frame  11 , the shifter lock-arm  44  cannot engage into the crab-steering link  32 . The shifter lock-arm roller bearing at the end of the arm will travel along the crab-steering link  32  until reaching the curved notch or recess  46  in the crab-steering arm or link  32  which is in-line with the shifter lock-arm roller thereby allowing the shifter to engage into the crab-steering link while at the same time disengaging from the turn-steering link  31  which is now allowed to float freely. 
   It can be seen now that when the front wheel is turned, fork  13  again causes steering rod  33  to move fore and aft which again causes shifter frame  40  to move fore and aft but now carries with it the crab-steering link  32  that causes the rear wheel to move parallel with the front wheel which now allows the scooter to move at an angle to the central longitudinal axis of the frame and housing in a crab sideways direction. 
   The operator of the scooter or vehicle is now able to move left or right in a crab fashion as long as the operator holds the handle bar lever  20  in a closed or pulled position. When the operator decides to turn, the operator simply relieves tension on the hand lever. When the operator stops the crabbing direction either left or right and the front wheel is aimed straight forward, the curved recess  45  in turn-steering link  31  will align with shifter lock-arm  44  and return spring  50  will cause the shifter lock-arm to engage back into steering rod  31 , thereby putting the scooter or vehicle back into normal steering. 
   The shifter lock-arm  44  is allowed to move transversely across the midsection of the housing  40  since it is carried by the two swing-arms  47  and  48  which are allowed to pivot on four pivot point pins. 
   It should also be noted that the three bell cranks, two for the rear wheel and one for the front wheel, have permanently mounted vertical shafts which carry a bushing, such as bushing  55  on post  36 . The bushing drives the steering links in a fore and aft direction as the wheels turn. In the manner shown, the steering links have slots at their respective ends that run transversely in which the bearings reside. This allows the shifter frame  40  to stay centered in the scooter frame  11  and not be forced left or right as the links or bell cranks swing in an arc when the wheels are turned. 
   In view of the foregoing, it can be seen that a unique feature of the present invention is that there is no attachment points of the steering linkage or shifting units to the platform or framework  11  of the vehicle. The complete shifter and transmission unit and steering links float free inside the scooter frame and are only connected to the pivot points of the bell cranks or forks. This greatly facilitates assembly and maintenance of the vehicle. Since most scooters fold their handlebar assembly down and most carry along the front wheel assembly, the slot at the end of the steering rod  33  allows for quick disconnect from the front wheel assembly. 
   While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

Technology Classification (CPC): 1