Abstract:
The present invention is a clutch assembly for use with motor driven toys, particularly a toy vehicle configured to be maneuvered on a surface. The clutch assembly includes a clutch operably coupled with the motor and a bell housing having at least one opening in its circumferential wall with a circumferential leading edge. At least an engagement end of the clutch is rotated within the housing. The clutch engagement end has finger members that resiliently flex outwardly from a center of rotation of the clutch. Each finger member has at least one small protrusion extending outwardly from the outside circumferential surface of the finger member that engages with the leading edge when the clutch is rotated and the finger member flexes outwardly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This patent application claims priority to U.S. Patent Application No. 60/386,374, filed Jun. 5, 2002, entitled “Non-Slip Clutch Assembly for Remote Control . . . . ” 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention generally relates to a clutch assembly, and more particularly to a non-slip clutch assembly for use with remote-controlled toy vehicles.  
           [0003]    Although clutch assemblies are generally known, they generally operate through frictional engagement between components of the clutch assemblies. The frictional clutch design allows three states of operation: disengaged, partially engaged, and fully engaged. This design is fine and, in fact, preferable in many applications. However, for some applications, it might be preferable to have a clutch assembly with only two states of operation: disengaged or fully engaged.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    Briefly stated, the present invention is a toy clutch assembly comprising a bell housing and a clutch. The bell housing has at least one opening with a leading edge. The bell housing is mounted for rotation about a central axis. The clutch is maintained at all times at least partially within the bell housing and is rotatable within the bell housing about the central axis. The clutch has at least one resiliently flexible finger member with an end that resiliently flexes outwardly away from the central axis during rotation. The at least one finger member has at least one small protrusion extending in a direction outwardly away from the central axis. The at least one protrusion engages with the leading edge when the finger member flexes outwardly at an engagement speed of the clutch. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0005]    The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.  
         [0006]    In the drawings:  
         [0007]    [0007]FIG. 1 is a perspective view of the toy vehicle in which the present invention is located;  
         [0008]    [0008]FIG. 2 is a perspective view of the toy vehicle of FIG. 1 with the top cover and rider removed;  
         [0009]    [0009]FIG. 3 is top plan view of the drive gear train of the toy vehicle of FIG. 1;  
         [0010]    [0010]FIG. 4 is an exploded view of the clutch assembly of the present invention;  
         [0011]    [0011]FIG. 5 is an end plan view of the clutch of the present invention;  
         [0012]    [0012]FIG. 6 is a perspective view of the noise-producing feature of the toy vehicle of FIG. 1;  
         [0013]    [0013]FIG. 7 is a perspective view of the bottom of the gear train housing cover of the toy vehicle of FIG. 1; and  
         [0014]    [0014]FIG. 8 is an exploded view of the toy vehicle of FIG. 1 with the top cover and rider removed. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]    Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “upper” and “lower” designate directions in the drawings to which reference is made. The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import.  
         [0016]    Referring to the drawings in detail, wherein like numerals indicate like elements throughout, there is shown in FIGS. 1 through 7 a preferred embodiment of a toy vehicle, indicated generally at  10 , in accordance with the present invention. Referring to FIG. 1, the vehicle  10  has a top cover  16  and a bumper  18  engaged with a chassis  28  (FIG. 2). The top cover  16  is designed to simulate a go-cart. Engaged with the top of the top cover  16  is a rider  20 , simulating a driver of the vehicle  10 . A power switch  26  behind the rider  20  in FIG. 1 (portrayed in phantom) extends upwardly from the top cover  16 , allowing a user to turn on or off the power for the vehicle  10 .  
         [0017]    Referring to FIGS. 2 and 8, the chassis  28  can be seen with the top cover  16  and the bumper  18  removed. Engaged with the chassis  28  are a steering mechanism housing  30 , a steering motor housing  32 , a drive mechanism housing  38 , and an on-board control unit  36 . Within the steering mechanism housing  30 , located proximate the front of the chassis  28 , is a conventional steering mechanism (not shown) powered by a conventional steering motor (not shown). The steering mechanism controls the pivoting of steerable wheels  12 , located proximate the front of the chassis  28 . Each steerable wheel  12  is rotatably mounted on a steerable wheel shaft  13 . The steering wheel shaft  13  is engaged with a wheel pivot member  34 , extending outwardly therefrom. The wheel pivot member  34  is pivotably mounted to the chassis  28  and also pivotably mounted to the steering mechanism, allowing the steering mechanism to pivot the pivot member  34  about its connection point with the chassis  28 . In this way, turning of the vehicle  10  is effectuated.  
         [0018]    The on-board control unit  36  is conventional and maintained within the vehicle  10 , engaged with the chassis  28 . An antenna  22  is engaged with the control unit  36 , extending upwardly therefrom through an opening in the top cover  16  (FIG. 1). The on-board control unit  36  includes a radio receiver circuit and an associated motor control circuit and is in electrical communication with the battery power supply (not shown) as well as both the steering motor and a drive motor  40  (FIG. 3). The on-board control unit  36  is configured to receive and process control signals transmitted from a remote control unit (not shown) spaced from the vehicle  10  to remotely control movement of the vehicle  10 .  
         [0019]    The drive mechanism housing  38  is located proximate the back of the chassis  28 . The drive mechanism housing  38  includes a removable drive mechanism housing cover  38   a . Removal of the drive mechanism housing cover  38   a  reveals a drive mechanism, indicated generally at  39  (FIG. 3). Referring to FIG. 3, the drive mechanism  39  includes the drive motor  40  and a gear train  41 . The drive motor  40  should be of a type that can provide a proper amount of power for the vehicle  10  and be maintained within the vehicle  10 , such as, but not limited to an electric motor or a small gasoline motor. A forward or a backward command received from the remote control unit will cause the drive motor  40  to rotate in the appropriate direction, transmitting power through the gear train  41  and effecting rotation of a drive wheel axle  15  located proximate the rear end of the chassis  28 . A pair of toy vehicle drive wheels  14 , one located at each end of the drive wheel axle  15 , are rigidly engaged with the drive wheel axle  15 , such that rotation of the drive wheel axle  15  effects rotation of the drive wheels  14 , thereby propelling the vehicle  10 . The gear train  41  has a first combined gear  42 , a toy clutch assembly  50 ; a second combined gear  44 , a first spur gear  46 , and a second spur gear  48 . The first combined gear  42  is rigidly engaged with the rotating member of the drive motor  40 . The smaller gear of the first combined gear  42  engages with the second spur gear  48 , which is rotatably maintained on the drive wheel axle  15 . The second spur gear  48  is rotatable regardless of whether the drive wheel axle  15  is rotating and is used to produce a motor-like sound, as will be described below. The larger gear of the first combined gear  42  engages with the toy clutch assembly  50 , which will be described below. The toy clutch assembly  50  engages with the larger gear of the second combined gear  44 . The smaller gear of the second combined gear  44  then engages with the first spur gear  46 . The first spur gear  46  is rigidly engaged with the drive wheel axle  15 , such that rotation of the first spur gear  46  causes rotation of the drive wheel axle  15 .  
         [0020]    Referring to FIGS.  3 - 5 , the toy clutch assembly  50  includes a clutch bell housing  52 , a clutch  54 , and a clutch gear  55 , all rotatably mounted on a clutch shaft  56 . The central axis of shaft  56  constitutes a central axis of assembly  50  and each component  52 ,  54 ,  55 . The clutch  54  is rigidly engaged with the clutch gear  55 . The clutch  54  is sized such that at least a proximal end portion of it fits and is maintained at all times within the clutch bell housing  52  without contacting the clutch bell housing  52  at any angular orientation, at least when the clutch is not being rotated. Referring to FIG. 5, the portion of the clutch  54  that is inserted within the clutch bell housing  52  includes at least one and preferably two, generally semi-circular, resiliently flexible finger members  54   a . Each member  54   a  has at least one small finger member protrusion  54   b  on the outer circumferential (radial) edge of each finger member  54   a  extending in a direction outwardly away from the central axis of shaft  56 , a finger member connection point  54   c  which connects the two finger members  54   a  to the rest of the clutch  54 , and a gap  54   d  between the ends of the two finger members  54   a . The finger members  54   a  are designed to flex resiliently radially outwardly from the center of the clutch  54  and central axis of shaft  56 . When the clutch  54  is rotated above a threshold rotational speed, flexing of the finger members  54   a  causes the finger member protrusions  54   b  to move beyond the original diameter of the clutch  54 , bending proximate the connection point  54   c  and widening the finger member gap  54   d  diametrically opposite the connection point  54   c , and come into contact with the clutch bell housing  52 . The threshold speed of the clutch  54  is dependent upon a spring tension of the finger members  54   a . The spring tension is a function of thickness and material of the finger members  54   a . In this way, the engagement speed can be adjusted by varying the thickness, shape and/or material of the finger members  54   a  to enable the toy clutch assembly  50  to work with a range of motor speeds for vehicles of different scale sizes and loading weights. Of course, engagement speed should be less than normal operating speed(s) to maintain engagement of the clutch assembly during operation.  
         [0021]    The clutch bell housing  52  has an opening  52   a , preferably elongated and rectangular, with an axially extending leading edge  52   b  on each of the left and the right sides (circumferential ends) of the opening  52   a  in FIG. 4. When the clutch  54  rotates and the finger members  54   a  flex radially outwardly, one of the finger member protrusions  54   b  will enter the clutch bell housing opening  52   a  and rotate into facing engagement with one of the leading edges  52   b , depending on which direction the drive motor  40  is rotating. Engagement in this way between the clutch  54  and the clutch bell housing  52  causes both to rotate at the same speed without slippage. This, in turn, causes the second combined gear  44  and the first spur gear  46  each to rotate, thereby causing rotation of the drive wheels  14 , propelling the vehicle  10 . It will be appreciated that clutch assembly  50  can be designed to transmit rotation in opposing directions by making opposing sides of each protrusion  54   b  generally planar and parallel to the central axis of shaft  56  and can make the assembly  50  a one-way or overrunning clutch by appropriately sloping one of the two opposing sides of each protrusion  54   b  with respect to the central axis to cam the protrusion from the opening  52   a .  
         [0022]    Referring to FIGS. 3, 6, and  7 , the vehicle  10  mechanically produces noise at all times when the power switch  26  (FIG. 1) is turned on. At all times when the vehicle  10  is powered, the drive motor  40  runs. If the vehicle  10  is not being commanded by a user to move either forward or backward, the drive motor  40  rotates at a speed below the threshold speed so as not to engage the toy clutch assembly  50  and propel the vehicle  10 . However, rotation of the drive motor  40  in either direction or at any speed causes rotation of the second spur gear  48 . The second spur gear  48  is the source of the noise produced by the vehicle  10 , the noise intended to simulate the sound of a real go-cart motor. The second spur gear  48  is freely rotatable about the drive wheel axle  15  so that noise can be produced whether or not the vehicle  10  is moving.  
         [0023]    The second spur gear  48  has four pivot members  49  rotatably engaged with and equally spaced about one (generally) circular (annular) face of the second spur gear  48 . The pivot members  49  are pivotally mounted to the second spur gear  48  at pivots  48   a  located generally circumferentially spaced around the drive wheel axle  15  through the second spur gear  48 . Each pivot member  49  has an elongate projection  49   a  extending outwardly from the pivot  48   a  of the pivot member  49 . Interspersed between pivot members  49  are abutments  48   b . The abutments  48   b  are L-shaped and situated such that, depending upon the rotation of the second spur gear  48 , the centripetal force will cause either the pivot members  49  to abut the short side of the abutments  48   b  so that the projections of the pivot members  49  extend outwardly radially from the center of the second spur gear  48  (during a forward direction of rotation) or abut the long side of the abutments  48   b  so that the projections of the pivot members  49  remain proximate the center of the second spur gear  48  (during a backward direction of rotation). Rotation in a forward direction causes the projections of the pivot members  49  to extend outwardly from the center of the second spur gear  48  and come into contact with a drum protrusion  58   b  extending downwardly from a small hollow plastic drum  58  engaged with and extending through the top of the drive mechanism housing cover  38   a . This percussive contact between the projections of the pivot members  49  and the drum protrusion  58   b , when quickly and successively repeated, approximates the sound of the engine of an actual go-cart. The noise produced is amplified within the drum  58 , exiting the drum through a drum opening  58   a  and entering a hollow muffler  24  (FIG. 1) engaged with the top cover  16  (FIG. 1). The sound then exits the muffler  24  through a muffler opening  24   a  (FIG. 1) so that it would seem as though the vehicle  10  were producing actual motor noise.  
         [0024]    In operation, the vehicle  10 , when turned on but not commanded to go either forward or backward, will produce motor noise but not move forward because the drive motor  40  is rotating at a speed that is less than the engagement speed of the toy clutch assembly  50 . When the vehicle  10  is commanded to go either forward or backward, the drive motor  40  rotates at a speed higher than the engagement speed, thereby engaging the toy clutch assembly  50  as described above and causing the vehicle  10  to be propelled.  
         [0025]    The operation of the toy clutch assembly  50  provides either complete disengagement, thereby allowing the vehicle  10  to produce noise but not move, or complete engagement, thereby allowing power to be transferred from the drive motor  40  to the drive wheels  14  with no power loss due to slippage of the toy clutch assembly  50  and causing the vehicle  10  to move and produce noise. This two-state toy clutch assembly  50  is made possible by the interference engagement between the finger member protrusion  54   b  and the clutch bell housing opening leading edge  52   b  when the clutch  54  is rotated at speeds higher than the engagement speed. The two-state toy clutch assembly  50  of the present invention allows for smooth forward and backward operation of the vehicle  10 . Use of an ordinary frictional clutch would result in jerky forward and backward motion and/or slow acceleration of the vehicle  10  due to partial clutch engagement (slippage), especially when encountering rough terrain or upward hills.  
         [0026]    It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. For example, while a separate chassis/separate body construction is disclosed, the vehicle may be formed by a pair of mated half-shells or other monocoque construction. “Chassis” is intended to cover both a conventional chassis supporting a separate mounted body and also a monocoque construction in which the body also functions as a chassis bearing loads on the vehicle. Although an electric motor and a gas engine are disclosed, other motors (i.e., spring, inertia wheel, compressed air) might supply rotary output through such clutch assembly.  
         [0027]    Although above-described toy clutch assembly  50 , consisting of the clutch bell housing  52 , the clutch  54 , and the clutch gear  55 , rotates about the clutch shaft  56 , it is within the spirit and scope of the present invention that an element may be rigidly engaged with the clutch shaft  56  such that it rotates with the clutch shaft  56 . Such rigid engagement of either the clutch  54  or the clutch bell housing  52  with the clutch shaft  56  may also eliminate the need for clutch gear  55  and/or the gear portion of the clutch bell housing  52 . It is further within the spirit and scope of the present invention that the toy clutch assembly  50  is engaged with either the drive motor  40  or the drive wheel axle  15  through means other than gears, such as belts and rigid links. Lastly, the present invention is not limited to use with toy vehicles; it may be used with any toys with motors. The motors with which the toy clutch assembly  50  may be used are not limited to electric; they may be of any type, including hydraulic, pneumatic, and spring.  
         [0028]    It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.