Abstract:
An drive assembly for an exercise bike consists of an electrical motor ( 10 ), a driven wheel ( 20 ), a unidirectional clutch ( 30 ), a flywheel ( 40 ), a shaft ( 47 ) and a crank wheel ( 50 ). The shaft ( 47 ) penetrates the driven wheel ( 20 ), the unidirectional clutch ( 30 ) and the flywheel ( 40 ). The driven wheel ( 20 ) is driven by the electrical motor ( 10 ) and then passes on the rotating momentum via the clutch ( 30 ), the flywheel ( 40 ), the belt wheel and the crank wheel ( 50 ) in sequence when the electrical motor ( 10 ) is switched on. The exercise bike can rotate in an automatic way to make the ordinary exercise bike into a physical therapy training bike.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an electrical drive assembly, and more particularly to a drive assembly used in an exercise machine, which allows the exercise machine to be used in an active or passive way.  
           [0003]    2. Description of Related Art  
           [0004]    Indoor sports and exercise have become much more popular in modern urban societies because people do not have enough time or space for outdoor sports. Thus the use of aerobic exercise machines such as exercise bikes, steppers, treadmills and fitness flyers has mushroomed, but the use of the individual exercise machines is limited. Take the exercise bike as an example, the exercise bike is a zero-impact exercise device and can be used by all people of different ages to exercise. However, the exercise bike is only used in a passive mode. That is to say, the exercise bike only works when a user rotates the exercise bike pedals. Therefore, an injured people who is unable to operate the exercise bike but needs physical therapy to recover from an injury cannot use the exercise bike for physical therapy.  
           [0005]    Toward the objective of using an exercise bike to improve the range of motion in and strength of a patient&#39;s legs, the present invention provides a modified electrical drive assembly for an exercise bike that allows the exercise bike to be operated in either an automatic or passive mode.  
         SUMMARY OF THE INVENTION  
         [0006]    The main objective of an electrical drive assembly for an exercise machine in accordance with the present invention is to allow the exercise machine to move automatically to provide training for people who need physical therapy for their feet or legs.  
           [0007]    Other advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is an exploded perspective view of an electrical drive assembly for exercise machine in accordance with the present invention;  
         [0009]    [0009]FIG. 2 is a perspective view of the electrical drive assembly in FIG. 1;  
         [0010]    [0010]FIG. 3 is a side plan view of the drive assembly in FIG. 2;  
         [0011]    [0011]FIG. 4 is a top plan view in partial section of the drive assembly along line  4 - 4  in FIG. 3;  
         [0012]    [0012]FIG. 5 is an operational perspective view of the drive assembly in FIG. 1 used on an exercise bike; and  
         [0013]    [0013]FIG. 6 is an operational side plan view of an exercise bike with the drive assembly in FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    With reference to FIGS. 1 and 2 an electrical drive assembly for exercise bike comprises an electrical motor assembly ( 10 ), a driven wheel ( 20 ), a unidirectional clutch ( 30 ), a flywheel ( 40 ), a shaft ( 47 ) and a crank wheel ( 50 ). The shaft ( 47 ) penetrates the driven wheel ( 20 ), the unidirectional clutch ( 30 ) and the flywheel ( 40 ) and has two distal ends respectively secured on two supporting frames ( 56 ,  561 ).  
         [0015]    The electrical motor assembly ( 10 ) includes a direct current motor ( 11 ) and a motor mount ( 13 ) to mount the motor ( 11 ) on the exercise machine. A toothed pinion ( 12 ) extends from and rotates with the direct current motor ( 11 ). A first driving belt ( 14 ) is mounted around the toothed pinion ( 12 ) and the driven wheel ( 20 ) to make the toothed pinion ( 12 ) and the driven wheel ( 20 ) rotate synchronously.  
         [0016]    The driven wheel ( 20 ) has two circular side faces with a center in each face. A shaft hole ( 21 ) is defined in the center of the driven wheel ( 20 ), and multiple positioning holes ( 211 ) are defined around the shaft hole ( 21 ).  
         [0017]    With reference to FIGS. 1 and 4, the unidirectional clutch ( 30 ) is securely mounted on one side-face of the driven wheel ( 20 ) and has a middle plate ( 31 ), a first insert ( 32 ) and a second insert ( 33 ). The first insert ( 32 ) is attached to one side of the middle plate ( 31 ) toward the driven wheel ( 20 ) to press into the shaft hole ( 21 ) in the driven wheel ( 20 ). Multiple positioning holes ( 311 ) are defined in the middle plate ( 31 ) around the first insert ( 32 ) to correspond to the positioning holes ( 211 ) in the driven wheel ( 20 ). A bolt (not numbered) penetrates each pair of aligned positioning holes ( 311 ,  211 ) to attach the clutch ( 30 ) to the driven wheel ( 20 ). The second insert ( 33 ) is attached to the other side of the middle plate ( 31 ) opposite to the first insert ( 31 ). A bearing mount ( 34 ) is axially defined in the center of the clutch ( 30 ) through the first insert ( 32 ) and the second insert ( 33 ). A unidirectional bearing ( 35 ) is securely mounted inside the bearing mount ( 34 ) to allow the clutch ( 30 ) to rotate in only one direction.  
         [0018]    With reference to FIGS. 1 and 3, the flywheel ( 40 ) is mounted adjacent to the clutch ( 30 ) and comprises a magnetic attractable face ( 41 ), a central shaft ( 42 ) and a belt wheel ( 45 ). The magnetic attractable face ( 41 ) forms an outer periphery of the flywheel ( 40 ) and serves to adjust a distance between a magnetic device ( 57 ) and the magnetic attractable face ( 41 ). Thus, the magnetic force on the magnetic attractable face ( 41 ) is adjustable by controlling the distance to make the flywheel ( 40 ) have different effort levels to operate the drive assembly. The central shaft ( 42 ) formed on one side of the flywheel ( 40 ) is rotatably inserted into the second insert ( 33 ) of the clutch ( 30 ). A through hole ( 421 ) is axially defined in central shaft ( 42 ) and through the flywheel ( 40 ). A central circular recess ( 43 ) is defined in the other side of the flywheel ( 40 ) and the belt wheel ( 45 ) is firmly received inside the central circular recess ( 43 ), wherein the belt wheel ( 45 ) further has a side wheel ( 452 ) secured on a free side of the belt wheel ( 45 ). A bearing ( 453 ) is mounted in the center of the belt wheel ( 45 ) to prevent direct friction between the belt wheel ( 45 ) and the shaft ( 47 ). Additionally, a lubricating sleeve ( 472 ) is mounted around the shaft ( 47 ) inside the central shaft ( 42 ) of the flywheel ( 40 ) to lubricate the joints of the shaft ( 47 ) and the other elements ( 20 ,  30 ,  40 ) secured on the shaft ( 47 ).  
         [0019]    The crank wheel ( 50 ) has a crankshaft ( 51 ) secured in the center to drive the crank wheel ( 50 ). A second driving belt ( 54 ) loops around the crank wheel ( 50 ) and the side wheel ( 452 ) on the belt wheel ( 45 ) to make the two wheels ( 50 ,  452 ) rotate synchronously. Additionally, a tension wheel ( 55 ) is rotatably mounted on the supporting frame ( 56 ) near the belt wheel ( 45 ) to slightly press the second driving belt ( 54 ) so that the second driving belt ( 54 ) tightly loops around the crank wheel ( 50 ) and the belt wheel ( 45 ) to avoid looseness.  
         [0020]    With reference to FIGS. 5 and 6, the electrical drive wheel assembly is mounted on an exercise machine such as a stationary bike. The exercise bike comprises a housing ( 70 ), a base ( 60 ), a seat ( 611 ) and an adjustable frame ( 62 ). The housing ( 70 ) has a top, two side-faces and is mounted on the base ( 60 ) to receive the electrical drive assembly inside. A seat post ( 61 ) with the seat ( 611 ) is attached to the top of the housing ( 70 ). The erecting frame ( 62 ) with two hand grips ( 621 ) is attached beside the side-faces of the housing ( 70 ). In this embodiment of exercise bike, the crankshaft ( 51 ) of the crank wheel ( 50 ) has two ends extending oppositely and outwardly to emerge from the side-faces of the housing ( 70 ). Each end has a foot pedal ( 53 ) attached to a distal end of the crankshaft ( 51 ). Additionally, an auxiliary housing ( 63 ) is constructed beside the housing ( 70 ) to particularly receive the electrical motor assembly ( 10 ) inside.  
         [0021]    When a normal user rides the exercise bike, the user can impose stepping force to the pedals ( 53 ) to make the crank wheel ( 50 ) drive, then the belt wheel ( 45 ) synchronously rotates and drives the flywheel ( 40 ). However, the magnetically attractable surface ( 41 ) is magnetically dragged by the magnetic device ( 57 ) so that the user can exercise his or her legs by adjusting the magnetic force of the magnetic device ( 57 ). When a patient needs physical therapy for his or her legs, the electrical motor ( 11 ) is switched on to rotate the driving wheel ( 12 ). The driven wheel ( 20 ) synchronously rotates with the driving wheel ( 12 ) and drives the flywheel ( 40 ) by the unidirectional clutch ( 30 ). Next, the belt wheel ( 45 ) also rotates to drive the crank wheel ( 50 ) rotates so that the pedals ( 53 ) are moved in a passive way and the patient can exercise the legs slowly with the rotating exercise bike.  
         [0022]    The electrical drive wheel assembly for an exercise bike in accordance with the present invention has a simplified structure as described. Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.