Patent Publication Number: US-2006019802-A1

Title: Removable crank arm for exercise cycle

Description:
This invention relates to a removable crank arm for an exercise bicycle and, more particularly, to a removable crank arm for an exercise bicycle which allows adjustable mounting of a pedal to the crank arm in order to provide greater or lesser movement of the limbs of a user.  
     BACKGROUND OF THE INVENTION  
      Exercise bicycles are, of course, well known. They are provided usually for fitness or training purposes. Because the pedal on which the user rests his foot moves in a circular path, impact blows to the user are avoided which is desirable to prevent aches and sprains to the joints and muscles. Such exercise bicycles are particularly useful for the elderly or for rehabilitation purposes.  
      Arthritic users are restricted in movement and the more prevalent the arthritis in the user, the more restrictive is the movement. While exercise is known to be beneficial for sufferers of arthritis, and while the movement of the pedals of an exercise bicycle is particularly advantageous because of the absence of shocks and impact to the user, the range of movement of the legs and knees of a user who is suffering from arthritis may not be sufficient to completely rotate the pedal arm to which the pedals are attached. It would be desirable to adjust the motion path of the pedals in order to increase or decrease the range of motion to be performed by the user so as to adapt to the movement of the individual user.  
      Various apparatuses have been designed to deal with the requirement for an adjustable path of the pedals. U.S. Pat. No. 5,316,532 (Butler) discloses an aquatic exercise cycle with a disc which allows incrementally spaced means to secure the legs of a user. U.S. Pat. No. 4,509,742 (Cones) teaches a hydraulic exercise cycle with a flywheel which allows incremental adjustment of the pedal assembly to the flywheel thereby allowing variable load resistance. Canadian application 2,235,465 (Saringer et al) teaches a flywheel to which resistance is adjustable by way of a control circuit. And Butterworth U.S. Pat. No. 6,589,139 teaches a primary and a secondary crank which allow or prohibit relative movement therebetween and which require tht the pedal arm be attached to the axis of the pedal arm assembly with a removable bolt and an additional member.  
      The prior art, however, does not teach an exercise bicycle which may be easily adjusted or modified to allow a reduced path of motion of a pedal for users who may lack the ability to participate in the full range of motion such as those arthritic users aforementioned.  
     SUMMARY OF THE INVENTION  
      According to one aspect of the invention, there is provided a removable crank arm for an exercise bicycle having a pedal arm with a pedal arm axis of rotation and having a first generally horizontal axle section and a second generally vertically extending pedal arm section, said removable crank arm comprising attachment means for attachment of said removable crank arm to said second generally vertically extending pedal arm section of said pedal arm of said exercise bicycle, said removable crank arm being rotatable about a crank arm axis and being operably connected to said pedal arm and being generally rotatable about said axis of rotation of said pedal arm, said removable crank arm further comprising a pedal operably mounted to said crank arm at at least one distance from said crank arm axis, said rotatable pedal rotating about a pedal axis of rotation relative to said crank arm, said removfable crank arm being connected to said pedal arm at a location other than said axis of rotation of said pedal arm.  
      According to a further aspect of the invention, there is provided a method of moving a pedal connected to a crank arm at a predetermined distance from the axis of rotation of said crank arm mounted on an exercise bicycle, said method comprising removing a pedal from a pedal arm which rotates about a pedal arm axis of said exercise bicycle, said pedal arm having a first generally horizontal axle section and a second generally vertically extending pedal arm section, mounting said crank arm on said second generally vertically extending pedal arm section by connecting said crank arm to said second generally vertically extending pedal arm section of said pedal arm such that said crank arm rotates about the axis of rotation of said pedal arm and mounting a rotatable pedal on said crank arm which pedal is adapted to be connected at at least two predetermined distances from the axis of rotation of said crank arm, said rotatable pedal rotating about a pedal axis of rotation, said crank arm being mounted to said pedal arm at a location other than said axis of rotation of said pedal arm. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
      Specific embodiments of the invention will now be described, by way of example only, with the use of drawings in which:  
       FIG. 1  is a diagrammatic isometric view of the exercise bicycle with the rotating crank arm illustrated in operative position according to the invention;  
       FIG. 2  is a rear view of the inside of the crank arm particularly illustrating the installed position of the crank arm on the pedal arm of the exercise bicycle according to the invention;  
       FIGS. 3A and 3B  are diagrammatic side and plan view of wedge clamps used to secure the crank arm to the pedal arm of the exercise bicycle according to the invention;  
       FIG. 4  is an outside diagrammatic view of the flywheel illustrating the pedal attachment holes according to the invention and the pedal arm being shown in broken lines;  
       FIG. 5  illustrates the attachment shaft used to connect the pedal to the crank arm according to the invention;  
       FIGS. 6A and 6B  are diagrammatic side and inside views of the crank arm, respectively, illustrating a further embodiment of the attachment of the crank arm to the pedal assembly; and  
       FIG. 7  is an outside view of the crank arm illustrating a further attachment technique of the crank arm to the pedal arm. 
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENT  
      Referring now to the drawings, an exercise bicycle according to the invention is generally illustrated at  100  in  FIG. 1 . It is of the type usually used in recreational and fitness centers and includes a seat  101  for a user, a read out device  102  and a frame  103  sed to enclose and support the movement of a rotating pedal  104  which is attached to a rotating crank arm  110 .  
      Rotating crank arm  110  is connected to a pedal arm  111  ( FIG. 2 ) in a manner to be described and rotates about a crank arm axis  112 . The pedal arm  111  comprises two well defined portions, namely a first generally horizontal axle section portion  200  and a second generally vertically extending pedal arm section  115  ( FIG. 6B ). The crank arm  110  includes a plurality of attachment holes  113  which allow the pedal  104  to be connected to the crank arm  110  at various distances from the axis  112 . The pedal  104  may have a heel cup  114  and a toe strap  120  which will allow the foot or shoe of the user to be securely held in place when using the pedal  104 .  
      Referring now to  FIG. 2 , the inside surface of the crank arm  110  is illustrated as being mounted on the generally vertically extending pedal arm portion  115  of the pedal arm  111  of the exercise bicycle  100 . The pedal of the pedal arm  111  is removed and the crank arm  110  is then mounted onto the pedal arm  111  by way of a groove  121  (also shown in  FIG. 3A ) which is machined in the crank arm  110 . Wedge assemblies  122  ( FIGS. 3A and 3B ) are provided to clamp the crank arm  110  onto the pedal arm  111  such that the axis  112  of the crank arm  110  is generally coincident with the axis of the pedal arm  111 . Set screws  123 ,  124  may be used to attach the wedge clamp assemblies  122  to the crank arm  110  and also to allow adjustable movement of the wedge clamp assemblies  122  when the crank arm  110  has reached its proper position on the pedal arm  111  so that the crank arm  110  is securely held on the pedal arm  111 .  
     OPERATION  
      In operation, the pedal (not illustrated) of the original pedal arm  111  of the exercise bicycle  100  will be removed and the wedge claim assemblies  122  will be opened to allow entry of the pedal arm  111  of the exercise bicycle into the grove  121  of the crank arm  110  which crank arm  110  is manipulated into position on the pedal arm  111 .  
      The crank arm  110  will be positioned on the pedal arm  111  so that the axis of rotation  112  of the crank arm  110  is coincident with the axis of rotation of the pedal arm  111  when under normal operation with the exercise bicycle  100 . When that position is reached, the set screws  123  will be rotated by, for example, a hex key (not illustrated) until the crank arm  100  is securely attached to the pedal arm  111 . Of course, while the attachment of only one crank arm  110  has been described, it will be appreciated that the same operation will occur on the side of the exercise bicycle  100  which is opposed.  
      Following the attachment of the crank arm  110  to the pedal arm  111  of the exercise bicycle  100  on both sides, the pedal  104  will be attached. Pedal  104  itself rotates about a pin  130  ( FIG. 5 ) which has a threaded end  131  and a head  132  which maintains the pedal  104  on the pin  130 . The holes  113  are threaded and complementary to the threads on pin  130  so that the pin  130  and attached pedal  104  can be attached to whatever hole  133  is deemed appropriate for the user. For example, if the degree of arthritis suffered by he user is high or if injury rehabilitation dictates an initial and very small movement of the limb of the user, the holes  113  closest to the axis of rotation  112  of the crank arm  110  may be dictated for pedal and pin attachment. Conversely, as the degree of flexibility and limb movement of the user increases, the pin  130  and attached pedal  104  can be threadedly attached to a hole  113  further removed from the axis of rotation  112  of the crank arm  112 .  
      The user will then assume the usual position on the exercise bicycle  100  and with his feet in the pedal  104 , he will rotate the crank arm  110  thereby obtaining exercise and proper movement of the intended limb.  
      The crank arm  110  may be attached to the pedal arm  111  is a variety of different ways and a further method of attachment is illustrated in  FIGS. 6A and 6B . In this attachment technique, the horizontal arm  200  of the pedal arm  111  is positioned in a cradle  201  which is mounted to the crank arm  110 . This cradle  201  may be movable between attachment holes or by way of a sliding movement in an oblong hole such as that hole  202  such that the crank arm  110  rotates about the axis of rotation of the pedal arm  111 . Following the proper positioning of the pedal arm  111  and pedal arm cradle  201 , the hole  203  of the pedal arm  111  to which the pedal is originally attached is aligned with a hole  202  in the crank arm  110  and a bolt or pin  204  secures the pedal arm  111  to the crank arm  110 . Thereafter, the pedal  104  is connected on one of the series of holes  113  which are machined into the outside surface of the crank arm  110 .  
      Yet a further attachment technique illustrated in  FIG. 7 . In that embodiment, the pedal arm  111  is connected to the wedge clamps  122  as already described in association with the embodiment of  FIGS. 2 and 3 . However, the crank arm  110  has a countersunk hole  300  drilled through its thickness and a complementary flat head bolt  301  in positioned in the hole  300  and extends through the join the pedal arm  111  at the hole in the pedal arm  111  previously occupied by the pedal  104 . Thus, the crank arm  110  will rotate with the pedal arm  111  in precisely the same manner as previously described with the pedal  104  being connected to any one of the machined holes  302  depending on the extent of movement ability possessed or desired by the user.  
      Many further embodiments will readily occur to those skilled in the art to which the invention relates and the particular embodiments described are given by way of example only and are not intended as limiting the scope of the invention as defined in accordance with the accompanying claims.