Muscle powered therapeutic vehicle

A therapeutic wheeled vehicle particularly suited for strengthening the hip extensor muscles of a user is described. The vehicle combines the therapeutic benefits of conditioning the hip extensor muscles with the enjoyable activity of propelling oneself on a wheeled vehicle. A frame is provided following the general pattern of a tricycle with one steerable wheel and a pair of driving wheels. A seat, a back rest, and at least one strap for holding the user in position on the seat and the back rest are also provided. These user support structures securely hold the user in the proper operating position, even when the user has less than normal muscular control and strength, such as with children with cerebral palsy. Structures are included for receiving at least a portion of the user's leg between the user's knee and the user's hip and for transmitting the extension motion of the user's hips into the rotational movement of the pair of driving wheels. Substantially only the hip extensor group of muscles of the user are used to propel the vehicle.

BACKGROUND 
1. The Field of the Invention 
This invention relates to human powered vehicles. More particularly, the 
present invention relates to therapeutic devices which are used to provide 
conditioning of specific muscles of the human body. 
2. The Prior Art 
The benefits of muscle powered activities are universally recognized. For 
example, the physiological benefits of pedaling a muscle powered wheeled 
vehicle, such as a bicycle or a tricycle, are well known. Unfortunately, 
some who need the benefits of such exercise the most are unable to use 
previously available bicycles and even tricycles. 
In particular, children afflicted with cerebral palsy are generally unable 
to operate any of the previously available tricycles which are enjoyed by 
other children. Moreover, both adults and children may be afflicted with 
other disorders which make operating previously available bicycles and 
tricycles difficult or impossible. Thus, such persons are denied the 
benefits which accrue from such activities. 
In particular, it is often the case that a person lacks either the muscle 
strength or coordination in the hip extensor muscles. Hip extensor muscles 
are critical for walking since they prevent trunk flexion and collapse. 
The hip extensor muscles are one of the major support muscles of the body 
used in standing and walking. Weakness of the hip extensor muscles cannot 
be treated with external bracing as is often the case with more distal 
muscles. 
Moreover, in children with cerebral palsy who have undergone the selective 
dorsal rhizotomy procedure to reduce spasticity, hip extensor muscle 
weakness is frequently very pronounced. It is often the case that physical 
therapists work extensively (often for years) to strengthen these muscles 
in children with cerebral palsy. As a general rule, it is very difficult 
to strengthen muscles in children; they refuse to lift weights. However, 
children will ride tricycles. Disadvantageously, a conventional tricycle 
does not strengthen the hip extensor muscles; it primarily strengthens the 
quadriceps muscles. 
Even though the is has been known for a long time that many persons, 
including children with cerebral palsy, are unable operate previously 
available tricycles, the problem of providing a muscle powered vehicle 
which can be operated by persons with particular disorders, and which will 
benefit such persons, has been unrecognized. Thus, in view of the 
inability of many individuals, for example children with cerebral palsy, 
to operate previously available bicycles and tricycles, it would be an 
advance in the art to provide a muscle powered wheeled vehicle which can 
be used by such individuals and which provides therapeutic conditioning to 
the hip extensor muscles. 
BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
In view of the above described state of the art, the present invention 
seeks to realize the following objects and advantages. 
It is a primary object of the present invention to provide a wheeled 
apparatus which can be powered by a person with impaired muscle control. 
It is yet another object of the present invention to provide a muscle 
powered wheeled vehicle which can be operated by a child afflicted with 
cerebral palsy. 
It is another object of the present invention to provide a muscle powered 
wheeled vehicle which will promote improvement in the walking gait of 
children with cerebral palsy. 
It is a further object of the present invention to provide a muscle powered 
wheeled vehicle which promotes activation of the hip extensor muscles in a 
similar or greater amount than walking. 
The present invention provides a therapeutic wheeled vehicle particularly 
suited for strengthening the hip extensor muscles of a user. The present 
invention combines the therapeutic benefits of conditioning the hip 
extensor muscles with the enjoyable activity of propelling oneself on a 
wheeled vehicle. Children, particularly those with disorders such as 
cerebral palsy, benefit from the present invention. 
Embodiments of the present invention include a frame which is preferably 
constructed using materials and techniques similar to those used in 
bicycle and tricycle construction. The preferred embodiment of the present 
invention follows the general pattern of a tricycle having one steerable 
wheel and a handlebar connected to the frame and a pair of driving wheels 
connected to the rear of the frame. 
A seat, a back rest, and at least one strap for holding the user in 
position on the seat and the back rest are also provided. These user 
support structures securely hold the user in the proper upright operating 
position, even when the user has less than normal muscular control and 
strength. 
Importantly, the present invention includes means for receiving at least a 
portion of the user's leg between the user's knee and the user's hip 
preferably including means for receiving the back of the user's thigh. The 
present invention also includes means for transmitting the reciprocating 
movement of the user's hip into the rotational movement of the driving 
wheel or wheels such that the vehicle can be propelled by the hip movement 
of the user. The desired hip movement of the user is extension of the hip 
joint. In the preferred embodiment of the present invention, each of the 
user's legs are coupled to the driving wheels such that as the hip joints 
are alternately moved to extend the legs of the user the vehicle is 
propelled. Substantially only the hip extensor group of muscles are used 
to propel the vehicle thus providing conditioning for that specific group 
of muscles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference will now be made to the drawings wherein like structures will be 
provided with like reference designations. 
FIG. 1 provides a perspective view of the presently preferred example the 
therapeutic vehicle of the present invention. The described embodiment is 
particularly suited for use by children with cerebral palsy. Those skilled 
in the art will appreciate that the present invention has application with 
persons other than children and with disorders other than cerebral palsy. 
Still, the illustrated therapeutic vehicle will be described herein as 
being used with children having cerebral palsy with the understanding that 
the teachings provided herein can readily be used to provide therapeutic 
vehicles to benefit others. 
As mentioned, children with cerebral palsy generally have deficient 
strength and control in the group of muscles used to extend the hip joint. 
The group of muscles involved in the extension motion of the hip 
principally includes the gluteus maximus muscle as well as, to a lesser 
extent, the biceps femoris, the semitendionosus, and the semimembranosus 
muscles which will collectively be referred to herein as the "hip extensor 
muscles." 
Since the hip extensor muscles are critical to having a proper walking 
gait, these muscles must be developed in order for a child to walk 
properly. Unfortunately, children are notoriously uncooperative when 
required to engage in therapeutic exercise per se. With the therapeutic 
vehicle of the present invention, the hip extensor muscles are generally 
activated to a greater extent than with other modes of therapy suitable 
for children and the children find operating the vehicle to be an 
enjoyable activity. Thus, the child obtains the benefit of the therapeutic 
hip extensor muscle action while enjoying a common childhood activity 
which could not otherwise be enjoyed. 
The therapeutic vehicle, generally represented at 10 in the figures, 
includes a frame, generally indicated at 12, and three wheels 32, 34, and 
35, a handlebar 28, a seat 36, and drive components which will be 
described in detail later. Importantly, the vehicle 10 is configured as a 
three wheel tricycle to ensure a proper amount of stability and safety for 
the user. It is, however, within the scope of the present invention to use 
only two wheels, or more than three wheels, in embodiments of the present 
invention. 
The frame 12 is preferably constructed using techniques used to construct 
bicycle frames. The frame 12 of the illustrated vehicle 10 includes a top 
tube 18, a rear driving wheel tube 22, a hanger tube 20, a down tube 16 
and a head tube 14. The particular frame geometry illustrated in the 
figures is preferred but many other frame geometries and types of 
frame-like structures can be used within the scope of the present 
invention. 
The front wheel 32 is attached to a fork 24 which is rotatably mounted in 
the head tube 14 preferably using bearing structures (not represented in 
the figures) available in the art. A stem 26 connects the handle bar 28 to 
the fork 24. The handle bar 28 is provided with grips 30 as is known in 
the art. The front wheel and the components associated with it are used to 
steer the therapeutic vehicle 10. As will be appreciated by those skilled 
in the art, these structures can be fabricated using components and 
techniques known in the art or one skilled in the appropriate art can take 
advantage of other components and techniques which would be suitable for 
fabrication of an embodiment of the present invention. 
The illustrated therapeutic vehicle 10 includes two rear driving wheels 34 
and 35, which, as in the case of the front wheel 32, preferably are of the 
type generally used in the bicycle and tricycle art. The rear driving 
wheels 34 and 35 are connected to an axle 66 which is connected to the 
frame 12 by way of bearing member 67, as shown best in FIG. 3. As will now 
be explained, the axle 66 is coupled to the legs of the user (not 
represented in the figures) so that the action of the hip extensor muscles 
alone will propel the therapeutic vehicle 10 thereby providing 
conditioning to said group of muscles. 
As mentioned, the illustrated therapeutic vehicle 10 is particularly 
intended for use by children having cerebral palsy who, in order to obtain 
maximum benefit from the present invention, require support structures to 
keep their body in position as they use their hip extensor muscles to 
propel the therapeutic vehicle 10. In order to provide such support, a 
seat 36 and a back rest 42 are provided in the illustrated therapeutic 
vehicle 10. In order to transmit the action of the hip extensor muscles to 
the rear driving wheels 34 and 35, a crank 50 is provided for each leg of 
the user. Each of the cranks 50 hang from pivots 49 as will be explained 
more fully shortly. 
As shown best in FIG. 2, a seat 36 is provided to give vertical support to 
the user. The seat 36 is connected to a seat post 39 which can be locked 
into a vertical position using a locking bolt 37. A seat arm 40 is 
connected to a support tube 38 which is connected to the top tube 18 of 
the frame. The seat post 39 slides vertically within a sleeve 41 until the 
locking bolt 37 is tightened. 
Referring now to FIG. 3, for best results, the height of the seat 36 should 
be adjusted in the direction of arrow B so that the hip joints of the user 
are at the same height as the crank pivots 49. Thus, lining up the crank 
pivots 49 approximately with the acetabulum, slightly above the greater 
trochanter of the hip, will generally be satisfactory. Other positions, 
however, may also be used as determined by experience with users of the 
therapeutic vehicle 10. 
Referring now to the side view of FIG. 2, the back rest 42 is also provided 
to keep the user in the proper upright position. Also included is a strap 
44 which wraps around the torso of the user and keeps the back of the user 
against the back rest 42. As can be seen best in FIG. 1, the back rest 
preferably has a curved shape to cradle the user's torso. The strap 44 is 
preferably provided with lengths of hook and pile fastener (one patch of 
which is represented at 46) to hold the strap together around the user. A 
buckle or some other type of fastener can be used on the strap 44 in place 
of the preferred hook and pile fastener 46. 
As illustrated best in FIG. 2, the back rest 42 can be moved forward and 
backward in the direction of arrow A. The back rest 42 is attached to a 
back rest post 74 which passes through a sleeve 72. A locking bolt 76 
positioned on the sleeve 72 holds the back rest 42 in position when 
tightened. A strut 70 connects the sleeve 72 to the support tube 38. While 
use of the user support structures described herein is preferred, other 
arrangements may also be used within the scope of the present invention. 
Furthermore, it is within the scope of the present invention to orient the 
user in positions other than the described upright position. 
While being securely held in the proper position, the user can propel the 
therapeutic vehicle by using substantially just the hip extensor muscles. 
The drive train components, which will now be described in detail, 
function to couple the movement of the hip extensor muscles to the driving 
wheels 34 and 35. As will be appreciated, the drive train components used 
in embodiments of the present invention should provide support for the 
legs of the user so that primarily the hip extensor muscles are used and 
lack of strength or coordination in other muscles does not hinder the use 
of the present invention. 
As illustrated best in FIG. 1, the cranks 50 are shaped so that as the 
user's leg is rested thereupon the knee of the user is comfortably bent. A 
thigh support 52 is included on the crank 50 and receives the back of the 
user's thigh. A calf support 54 is also provided on the crank 50 to hold 
the user's calf in place. A foot rest 56 receives the user's foot and a 
strap 58, which can be provided with some type of fastener such as a hook 
and pile fastener, holds the user's foot in place. Similarly, if desired, 
the thigh support 52 and the calf support 54 can also be provided with 
straps to hold the user's legs in place. 
A first connecting rod extension 60 is pivotally connected to each of the 
cranks 50. Each of the connecting rod extensions 60 are attached to a 
connecting rod 62 which is in turn joined to a second connecting rod 
extension 64 which is rotationally connected to the eccentric portion of 
the axle 66. 
Preferably, the effective length of the connecting rod 62 can be altered to 
increase or decrease the mechanical leverage provided between the cranks 
50 and the axle 66. It is also within the scope of the present invention 
to provide a friction brake on one or more of the wheels 32, 34 and 35, or 
on the axle 66 or other structure in order to provide additional 
mechanical resistance to the propulsion of the therapeutic vehicle or to 
limit the speed thereof. 
In the described therapeutic vehicle 10, the connecting rod 62 is provided 
with internal threads (not shown) which are engaged by external threads 
(not shown) provided on the first connecting rod extension 60 and the 
second connecting rod extension 64 and which allow the combined length of 
these structures to be increased or decreased by rotating the rod 62. A 
flat 61 is provided on the rod 62 to allow the rod to be gripped by a 
wrench and turned. Other structures can also be used, such as a turn 
buckle (not represented), to alter the length of the structures connecting 
the cranks 50 to the axle 66. It will be appreciated that it is also 
within the scope of the present invention to provide structures which 
allow changing the position at which a structure corresponding to the 
first connecting rod extension 60 is joined to the crank 50 or the 
changing eccentricity of the eccentric portion of the axle 66. Moreover, 
while the illustrated structure is preferred, it is within the scope of 
the present invention to use completely different arrangements to couple 
the movement of the user's hip extensor muscles to the driving wheels. As 
will now be appreciated, using the structure represented in the figures, 
as the user alternately activates his left side and right side hip 
extensor muscles, the cranks 50 will alternately pivot resulting in the 
rotation of the rear driving wheels 34 and 35. 
In view of the foregoing, it will be appreciated that the present invention 
provides a muscle powered wheeled vehicle which can be readily operated by 
a child afflicted with cerebral palsy and which conditions the hip 
extensor muscles as it is used. The strengthening of the hip extensor 
muscles provided by the present invention promotes improvement in the 
walking gait of children with cerebral palsy and others as well. The 
present invention also provides a therapeutic vehicle which promotes 
activation of the hip extensor muscles in a similar or greater amount than 
walking and which is often more productive than other types of therapy. 
The present invention may be embodied in other specific forms without 
departing from its spirit or essential characteristics. The described 
embodiment is to be considered in all respects only as illustrative and 
not restrictive. The scope of the invention is, therefore, indicated by 
the appended claims rather than by the foregoing description. All changes 
which come within the meaning and range of equivalency of the claims are 
to be embraced within their scope.