- BACKGROUND OF THE INVENTION
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.
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.
- SUMMARY OF THE INVENTION
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.
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.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
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.
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
DESCRIPTION OF SPECIFIC EMBODIMENT
FIG. 7 is an outside view of the crank arm illustrating a further attachment technique of the crank arm to the pedal arm.
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.
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.