Four-line exercising attachment for wheelchairs

A four limb exercising attachment for wheelchairs which will permit the occupant of the wheelchair to exercise all four limbs simultaneously, thereby affording proper bilateral movement of the arms and legs. The exercising attachment will also propel the wheelchair when operated in a suitable manner. The attachment may be used with most standard wheelchairs of the type having right and left front and rear wheels. The attachment includes right and left mounting assemblies, each mounting assembly being securable to the frame of a standard 4 wheel wheelchair at three or more spaced apart locations. A common input shaft will extend between the left and right mounting assemblies after they are mounted upon the wheelchair. Left and right arm-drives in the form of levers and leg-drives including foot pedals are in turn interconnected to the common input shaft in such a manner that movement of the arm levers will cause corresponding movement of the foot pedals and vice versa, which movement can be suitably synchronized. A resistance device is in turn connected to the common input shaft, which resistance device may include a propulsion assembly. Finally, steering devices are provided in the forms of manually operated brakes.

TECHNICAL FIELD 
The present invention relates generally an attachment device for 
wheelchairs which will permit the occupant of the wheelchair to exercise 
all four limbs simultaneously to afford proper bilateral movement of the 
arms and legs. The exercising attachment will also provide for propelling 
the wheelchair when operated in a suitable manner. 
BACKGROUND OF THE INVENTION 
There are currently large numbers of wheelchair bound individuals, 
throughout the world, who would realize health benefits through increased 
exercise. These groups include, but are not limited to, the paralyzed, 
stroke victims, amputees, the aged, and those with cerebral palsy. These 
people to a large extent must rely on a wheeled device such as a 
wheelchair for effective mobility. This type of transportation typically 
fails to promote any exercise or movement of the handicapped limbs which 
leads to varied medical problems. Increased exercise would decrease the 
incidence of muscle atrophy, osteoporosis, venous stasis (poor 
circulation), decubitus ulcers (bed sores), and stiffening of joints. In 
this regard it should be noted that muscular atrophy is due to the lack of 
muscle activity. Similarly, the incidence of osteoporosis is also 
increased as a result of disuse of a limb. Venous stasis is due to the 
lack of muscle contractions. In a healthy limb continuous contraction of 
the muscle helps push the blood through the circulatory system. This is 
especially important in the lower limbs and the lack of muscle 
contractions is why the blood tends to pool in the feet and ankles of 
paralyzed persons leading to swelling. Decubitus ulcers are the result of 
pressure points (i.e., between a bone and a bed or seat) which stops the 
flow of blood to part of the tissue. (In a healthy person, fidgeting keeps 
such problems from developing.) The lack of circulation tends to lead to a 
breakdown of the tissue and often infection. Finally, stiffening of the 
joints also results from disuse of a limb. Exercise would also lead to 
cardiovascular conditioning and an overall increase in the quality of 
life. Cardiovascular deconditioning is the result of inadequate exercise 
and this inadequacy is due to the limited muscle mass available in the 
arms which inherently limits our cardiovascular exercise capability to 
two-thirds that of our leg cardiovascular exercise capability. 
In summary it should be noted that if an individual is confined to a 
wheelchair and does not get proper exercise the body will deteriorate. The 
effect on the mental health of a person with paralysis who is slowly 
watching his or her body deteriorate is obviously of importance. Their 
efforts to maintain a positive outlook would be helped by keeping the 
paralyzed limbs in good shape. This would also aid in full recovery if a 
treatment is ever developed for the cause of their paralysis. For a person 
without paralysis, normal walking is sufficient to avoid experiencing any 
of the above symptoms. 
The need for exercise has long been recognized and many differing designs 
have been proposed in recognition of this need. U.S. Pat. Nos. 4,316,616 
and 4,471,972 have both proposed exercising attachments which can be added 
to the front of a wheelchair which will provide for rotational movement of 
the arms while at the same time causing the wheelchair to be propelled in 
a forward direction. U.S. Pat. Nos. 4,572,501 and 4,824,132 additionally 
teach not only rotational movement of the arms but also rotational 
movement of the feet to provide for suitable exercising, the rotational 
movement of the feet being achieved through a normal bike-pedal mechanism. 
In the four designs mentioned above, there is an insufficiency of 
exercising of the arms by the crank-type mechanisms illustrated. The first 
two patents do not teach any exercising for the legs and while the second 
group achieves desirable leg exercising, they do it in devices which must 
be disconnected from a wheelchair before the patient can be transferred to 
or from the wheelchair. None of the foregoing patents disclose exercising 
of the arms where there is almost full extension and retraction of the 
arms, which is considered a better form of exercise. 
A large number of patents show lever devices which can be mounted on 
wheelchairs of either a conventional design or of a special design. These 
levers have an upper handgrip portion and are pivotally interconnected to 
the wheelchair at their lower end. In operation, these levers can be 
pivoted from a forward arm extended position to a retracted arm position 
to provide for forward movement. Representative U.S. Pat. Nos. are: 
4,840,076; 4,811,964; 4,762,332; 4,735,431; 4,560,181; 4,506,900; 
4,503,724; 4,453,729; 4,358,126; 4,354,691; 3,994,509; 3,877,725; 
3,666,292; 2,643,898, 2,578,828; and 838,228. 
All of the patents mentioned in the previous two paragraphs have various 
design defects, some requiring chairs of special design, and others 
requiring substantial modification to existing chairs. Others do not 
maintain bilateral motion of the arms and legs. Many designs do not permit 
the normal lateral transfer of the occupant to and from the wheelchair. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a four-limb exercising 
attachment for most standard wheelchairs of the type having right and left 
front and rear wheels, which attachment when properly used will provide 
suitable exercising for the wheelchair occupant. 
A further object of the present invention is to provide an exercising 
attachment for most standard wheelchairs which can be attached with as few 
modifications as possible. 
It is a further object of the present invention to provide an exercising 
attachment for wheelchairs which permits the leg-drive means and at least 
one of the arm-drive means to be stored in such a position that it would 
not affect normal lateral transfer (over the side of the wheelchair) or 
the normal use of the wheelchair. 
It is a further object of the present invention to keep the weight of the 
entire drive as low as possible so that the wheelchair is readily 
transferable to or from a car, etc. This is also done for the obvious 
reason that a heavy wheelchair is more difficult to drive up inclines and 
across rough terrain (grass, dirt). 
It is a further object of the present invention to provide a four-limb 
exercising attachment for standard wheelchairs, which exercising movement 
may also be used to propel the wheelchair in a forward direction, and 
wherein nothing is attached to the main rear wheels of the standard 
wheelchair. This is because the rear wheels and their attachment points 
are not standardized in any way. Therefore, attachment to the rear wheels 
would require many different designs which would limit the economies of 
mass production. 
It is a further object of the present invention to have a direct connection 
between the hands and feet so that the frequency of the hand-drive can be 
utilized to control the frequency of the stimulation of the paralyzed 
limbs and to maintain bilateral movement. 
A further object of the present invention is to utilize variable gearing 
for the drive system. The reason for this is that very low gearing may be 
needed to climb slopes such as wheelchair ramps, but that gearing for 
moving on level smooth ground should be such that the necessary number of 
arm and leg cycles per second are in a reasonable envelope. 
It is a further object of the present invention to design a leg-drive means 
for adjustment to a wide range of leg lengths. This will limit the number 
of models necessary to fill the needs of almost anyone. 
It is a further object of the present invention to keep the center of 
gravity of the entire wheelchair, drive system, and occupant in a 
reasonably low position to prevent tipping. Since a wheelchair with a 
drive system has a potential to travel faster than a standard wheelchair, 
it is desirable that it does not have a greater tendency to tip over than 
a standard wheelchair. 
It is a further object of the present invention to provide a four-limb 
exercising attachment for wheelchairs wherein the drive system is fairly 
efficient at translating arm and leg movement into forward motion. This is 
desirable to permit the operation of the exercise wheelchair with people 
of very low strength and would also permit the wheelchair to be used for 
mobility purposes rather than just as an exercise machine. Physiologically 
speaking, this is also a desirable characteristic since it improves the 
user's sense of well-being. 
It is a further object of the present invention to permit the effort to be 
applied by a single limb only while imparting motion to the other limbs in 
such a manner that bilateral stability is achieved. 
Another object of the present invention is to design a four-limb exercising 
attachment for wheelchairs which would have the ability to allow exercise 
while sitting still. This would allow an occupant to exercise at a desk, 
etc., to aid circulation and thus replace normal fidgeting. 
The foregoing objects and other objects and advantages of the present 
invention are accomplished by providing an attachment having right and 
left mounting assemblies, each mounting assembly being securable to the 
frame of a standard 4 wheel wheelchair at three or more spaced apart 
locations. A common input shaft will extend between the left and right 
mounting assemblies after they are mounted upon the wheelchair. Left and 
right arm-drive means in the form of levers and leg-drive means including 
foot pedals are in turn interconnected to the common input shaft in such a 
manner that movement of the arm levers will cause corresponding movement 
of the foot pedals and vice versa, which movement can be suitably 
synchronized. Resistance means are in turn connected to the common input 
shaft, which resistance means may include propulsion means. Finally, 
steering means are provided in the forms of manually operated brake means. 
The foregoing design will be more fully understood after a consideration of 
the following detailed description taken in conjunction with the 
accompanying drawings in which two forms of the present invention are 
illustrated.

DETAILED DESCRIPTION 
In the following detailed description right-hand and left-hand reference 
will be determined from standing behind the wheelchair and facing its 
direction of travel. 
In the drawings two separate embodiments of the four-limb exercising 
attachment of the present invention are illustrated, both being indicated 
generally at 10. The first embodiment is shown in FIGS. 1 through 16, and 
the second embodiment is shown in FIGS. 17 through 21. As each of these 
designs has a number of common structural features, the same reference 
numerals will be applied with respect to each of the embodiments for 
reference to the same parts. 
The attachment of each of the embodiments is designed for mounting on a 
more or less standard wheelchair. 
The Wheelchair 
In the following description a wheelchair is described of the type having 
front right and left caster wheels 12, 14, respectively, and rear right 
and left main or drive wheels 16, 18, respectively. These front and rear 
wheels are in turn supported on right and left frame assembly 20, 22, 
respectively. Each of the frame assemblies is generally rectangular having 
upper and lower transversely extending frame members indicated by the 
suffixes ".1" or "0.4", respectively, and front and rear frame members 
indicated by the suffixes ".3" and ".2", respectively. Each of the frame 
assemblies 20, 22 further includes an upwardly inclined intermediate frame 
member indicated by the suffix "5". In the wheelchair design illustrated 
right and left rear wheel mounting assemblies are indicated generally at 
24, each assembly being secured to the intermediate and rear frame members 
22.5 and 22.2 or 20.5 and 20.2 to adjustably mount the associated rear 
wheel 16 or 18 to the frame assembly 20, 22. Each wheelchair further 
includes right and left seat frame members 26, 28, respectively, which are 
mounted on the associated upper frames 20.1 or 22.1 by associated seat 
supports 30. A seat 32 is carried by the right and left seat frame members 
26, 28. The rear frame members 20.2 and 22.2 extend above and behind the 
seat and a back 34 is disposed about these members. The upper end of the 
rear frame members 20.2, 22.2 are in turn bent backwardly and are provided 
with handgrips 36. Arm rests 38 are provided to either the right or the 
left side of the seat. In order to provide for lateral transfer of the 
wheelchair occupant, the arm rests are suitably telescopically received 
within arm rest brackets 40 mounted behind each of the right and left 
frame assemblies. Thus, each of the arm rests includes a vertically 
extending pipe-like portion the lower end of which is notched, which 
notched lower end rests upon a transversely extending pin 42 in the lower 
end of the arm rest brackets 40 so that by lifting up the arm rest 38 it 
can be swung 180.degree. so that the notch in the lower end can again rest 
upon the pin 42. Finally, the wheelchair includes a crossbrace assembly 
which, in the form indicated, includes two crossing tubular members 44, 
46, which crossing members are interconnected by a fastener assembly 48. 
The crossing frame members are conventionally pivotally secured at the 
their lower ends to an associated lower frame member 20.4 or 22.4, and at 
their upper ends they are rigidly secured to one of the right or left seat 
frame members 26, 28. While not shown, each of the wheelchairs will be 
conventionally provided with foot rests supported by the front right and 
left frame members 20.3, 22.3. 
The wheelchair thus far described is of a generally conventional design and 
the first and second modifications of this invention are shown mounted on 
such a conventional wheelchair. However, it should be obvious that other 
conventional wheelchair designs may be utilized in connection with the 
four-limb exercise attachment of this invention. 
The Attachments--In General 
While two embodiments of four-limb exercising attachments are illustrated, 
there is a certain commonality of features between them. Thus, each of the 
attachments has right and left mounting assemblies 50, 52. Each of the two 
illustrated exercising attachments has a common input shaft 54. Each 
embodiment has right and left arm-drive means indicated generally at 56, 
58, respectively, the arm-drive means being capable of imparting rotary 
motion to the input shaft 54. The right and left arm-drive means 56 and 58 
are interconnected to the right and left frame assemblies 20, 22, 
respectively. Each of the two embodiments further includes leg-drive means 
indicated generally at 60, the leg-drive means being connected to the 
common input shaft 54 for imparting rotary motion to the input shaft. Each 
of the two illustrated embodiments includes steering means in the form of 
right and left manually operated brake means, both brake means being 
indicated generally at 62. Each of the two designs has resistance means, 
or resistance/propulsion means, but the resistance means of the two 
designs differ significantly. Briefly though, the resistance/propulsion 
means of the first embodiment shown in FIGS. 1 through 16 imparts a 
driving motion to the right and left rear drive wheels 16, 18 by engaging 
the tread of each of these wheels with right and left friction drive 
wheels which are mounted upon the ends of an output drive-shaft assembly 
which includes an intermediate differential. In the design of the 
embodiment illustrated in FIGS. 17 through 21, the resistance/propulsion 
means includes a propulsion assembly further incorporating a fifth wheel 
mounted between the right and left main wheels 16, 18. The more or less 
common features will now be described in detail. 
In both embodiments the right and left mounting assemblies each includes a 
metal plate 64.2 or 64.1, the metal plates being mirror images of each 
other. These plates are in turn secured to the upper and lower right and 
left frame members 20.1, 20.4, 22.1, and 22.4 by suitable fasteners. Thus, 
in the first embodiment saddle-bracket assemblies 66 are utilized, whereas 
in the second embodiment U-bolts 68 are utilized for securing purposes. 
The mounting plates 64.1 and 64.2 of the first embodiment are further 
interconnected to each other by a transversely extending bar 65 which is 
rigidly secured by welding or the like at its ends to the two metal 
plates. Suitably journaled within the metal plates 64.1 and 64.2 is the 
transversely extending common input shaft 54. 
Right and Left Arm-Drive Means 
Each of the right and left arm-drive means indicated generally at 56 and 
58, respectively, includes a two part lever assembly having upper and 
lower parts 72, 74. The upper part includes an upper handgrip portion 72.1 
movable between forward and rear positions, as somewhat indicated in FIG. 
1. Each lower lever part includes a lower end portion 74.1 which is 
pivotally connected to an associated lever mounting assembly 76 suitably 
carried on one of the metal plates 64.1 or 64.2. Each lever further 
includes a lower intermediate portion 74.2 which is slidably received 
within a linear bearing 78. Linear bearing mounting means 80 are provided 
for mounting the linear bearing 78 for rotational movement about a 
transversely extending axis, such as that defined by the common input 
shaft, the linear bearing mounting means 80 for example being a circular 
disk rigidly mounted on one end of the input shaft 54 for rotation 
therewith. The levers 56 and 58 further include a tubular upper 
intermediate portion 72.2 which telescopically receives the upper end of 
the lower intermediate portion 74.2. These parts are so designed that they 
will not rotate with respect to one another when fully telescoped together 
but which will permit the upper intermediate portion 72.2 and the handgrip 
portion 72.1 to be moved upwardly away from the lower intermediate portion 
74.2 to disconnect the parts to permit lateral transfer of the user to or 
from the wheelchair as can be seen from an inspection of FIGS. 1, la, and 
16, the upper portion 72 being shown in its stowed position in FIG. 16. 
It is a feature of the arm-drives of the present apparatus that due to the 
design of the drives that the arm drives 56, 58 will always be maintained 
in a fixed relationship with each other. Thus, the common input shaft 54 
extends entirely from one side of the wheelchair to the other. The disks 
or linear bearing mounting means 80 are rigidly secured to the shafts. 
Thus, each of the right and left disks will always be turned the same with 
respect to the other. The left linear bearing 78 is mounted 180.degree. 
out-of-phase with the right linear bearing 78. This 180.degree. 
out-of-phase relationship can always be maintained. (In some situations it 
may be desirable to alter this relationship which can be done by changing 
the mounting of one of the bearings on its associated disk. In addition, 
the distance of the linear bearing 78 from the center of rotation of the 
linear bearing mounting means 80, which is defined by the centerline of 
the shaft 54, may also be suitably varied to increase or decrease the 
resistance imparted to the arms by the resistance means. However, once 
mounted, the selected relationship will always be maintained.) It should 
also be noted that there is a dead space for each lever at a forward or 
rear position. However, the dead spaces of one lever do not coincide with 
the dead space of the other lever. Thus, with reference to FIGS. 3a 
through 3d it can be seen that when a lever is engaging the linear bearing 
at its forwardmost position as shown in FIG. 3c, which for convenience 
will be referred to as a 0.degree. position, that rearward movement of the 
lever will impart a turning motion to the associated disk and will 
therefore impart a turning motion to the shaft 54. Maximum turning force 
is achieved when the linear bearing is in the 90.degree. position 
illustrated in FIG. 3b. When the same lever has achieved the 180.degree. 
position shown in FIG. 3c, continued rearward movement of the lever will 
continue to impart a slight rotational movement to the disk 80 as 
indicated by the arrow. Thus, when one lever is in the 0.degree. position 
and the other lever is in the 180.degree. position, it is possible to 
impart a turning motion to the shaft 54. Finally, when the linear bearing 
is in the 270.degree. position, as illustrated in FIG. 3d, forward motion 
to the lever will continue to impart rotational movement to the shaft 54. 
The forward dead spot for the levers 56, 58 are at a position where the 
linear bearing is in a right angle position to lines extending from the 
centerline of the shaft 54 through the center of the linear bearing and 
then to the center of the mounting assembly 74, this position being 
approximately 345.degree. in the forward position and approximately 
195.degree. in the rear position. Because of this offset drive 
relationship, it is always possible to propel the wheelchair with the 
arm-drive means. However, as a practical matter, if the levers are near a 
dead space position, it is easiest to start the wheelchair in a forward 
direction by engaging one or both of the handgrip rings 82 which are 
secured to the drive wheels 16, 18 to get the wheelchair moving and to 
then start reciprocating the levers to continue the forward motion, 
inertia carrying the levers past their respective dead spots. 
Steering Means 
The steering means of the present invention consists essentially of the 
right and left brake means which are capable of individually braking the 
right and left wheels 16, 18 to affect turning. Thus, if the right wheel 
16 is braked and forward power is directed to the left wheel 18, the 
wheelchair will turn in a right-hand direction. The brake means 62 
includes a brake-applying lever 84 associated with each of the handgrips 
72.1, the brake-applying lever being interconnected with a caliper brake 
mechanism 86 of the type conventionally used with handgrip-braking 
bicycles, the brake-applying lever 84 being connected with the brake 
mechanism 86 by means of a brake cable 88. While the upper lever portion 
72 can be removed from the lower lever portion 74, it is not necessary to 
disconnect the brake lever 84 from the brake mechanism as there is a 
sufficient length of cable 88 between the parts to permit stowage of the 
lever 68 at any convenient location. 
Leg-Drive Means 
The leg-drive means 60 includes a telescopic housing assembly indicated 
generally at 92, the telescopic housing assembly supporting at its forward 
end a transversely extending crank or drive shaft 94 which has right and 
left crank arms 96.1, 96.2 secured thereto. The crank arms support right 
and left foot pedals 98.1 and 98.2, respectively. 
While conventional pedals 98.1 and 98.2 are employed in both embodiments, 
it may be desirable to add full foot supports as shown in FIGS. 1 and 2. 
The full foot support includes a sole plate 100 which has mounted thereon 
suitable toe and heel clips 102, 104, respectively. Such an attachment 
will ensure that the feet be maintained on the pedals for patients who 
have no control of their feet. In order to provide for stowage of the 
telescopic housing assembly underneath the seat of the wheelchair, as will 
be necessary when performing a lateral transfer of the patient, one of the 
crank arms 96.1 or 96.2 may be rotated 180.degree. so that it lies 
parallel to the other crank arm, the stowage position being shown in FIG. 
16. At this point, it should be observed that as the seat and back of the 
wheelchair are not provided with fore and aft adjustment. Since the users 
of the wheelchair may have differing leg lengths, it is desirable to 
provide a drive means which is adjustable in length so that a single drive 
means may be provided for users having differing leg lengths. To this end 
an extendible and retractable drive is provided which is mounted in the 
telescopic housing. The telescopic housing assembly 92 includes a first 
housing assembly 106, and a second housing assembly 108 secured to the 
first housing assembly for telescopic adjustment thereto. 
Each of the housing assemblies 106, 108 include two clam-shell parts, one 
part acting as a support for various shafts, the support part being 
indicated by the suffix ".1", and the other part serving primarily as a 
cover, this part being indicated by the suffix ".2". Thus, the second 
support housing 108.1 rotatably supports the crank or drive shaft 94 at 
the location spaced away from the first housing 106, the shaft 94 having a 
drive sprocket 110 mounted thereon for rotation therewith. The first 
housing support 106.1 is supported about a driven shaft 112 in FIGS. 1 
through 3 and about the common input shaft 54 in FIGS. 17 through 19. 
Further mention of this will be made below. A driven sprocket 114 is 
secured to the associated driven shaft 112 or 54 for rotation therewith. 
The support housing 106 is journaled about the associated driven shaft 112 
or 54 for swinging movement and can be held in various positions of 
adjustment in a manner which will be more fully brought out below. 
The first housing support portion 106.1 as well as cover portion 106.2 
supports a first stub shaft 116 on which is mounted a first idler sprocket 
118. Similarly the second housing support portion 108.1 and cover 108.2 
supports a second stub shaft 120 on which is mounted a second idler 
sprocket 122. A chain 124 is disposed over the various sprockets 110, 114, 
118, and 122 and when the crank shaft 94 is caused to be rotated by rotary 
motion of the pedals 98 it will impart rotary motion to the associated 
driven shaft 54 or 112. Alternatively, if the associated shaft 54 or 112 
is caused to be rotated through the action of the arm-drive means 56, 58, 
the pedals will in turn be caused to be rotated. By selection of proper 
gearing, rotational movement of the pedals will be, maintained in 
synchronism with the arm-drive means. While not previously mentioned, a 
further stub shaft 126 and idler sprocket 128 are also mounted on the 
second housing portion 108. This will ensure that one flight of the chain 
124 does not interfere with another flight of the chain as it passes over 
the sprocket 118. As can be seen from FIGS. 4 and 7, the housing portion 
108.1 and 108.2 are provided with elongated slots 130 which receives the 
stub shaft 116 so that the second housing 108 can be moved relative to the 
first housing 106. When this occurs, as for example when moving from a 
retracted position shown in full lines in FIG. 4 to an extended position 
shown in phantom lines in FIG. 4, the distance from the sprockets 110 and 
114 will be increased, but the distance between the sprockets 118 and 120 
will be decreased the same amount as the sprocket 122 moves towards the 
sprocket 116. By providing the drive as illustrated it is possible to 
extend and retract the telescoping housing to provide for people with 
differing leg lengths. 
The housings can be held in their desired positions of adjustment by means 
of a pin 132 (FIG. 13) which is normally biased to an extended position by 
a spring 134 in housing 136, which spring can be moved to a retracted 
position by engagement with a button 138 to move the pin out of one of a 
plurality of aligned adjustment apertures 140 formed in the support 
housing 108.1. The operation of the adjustment mechanism should be 
apparent from FIG. 13. 
Drive Extension--First Embodiment 
As previously noted the telescopic housing means 92 of the leg drive means 
is connected to an intermediate drive shaft 112 in the first embodiment 
whereas in the second embodiment it is connected directly to the common 
input shaft 54. In the first embodiment the intermediate drive shaft 112 
is supported by a drive extension indicated generally at 142. The drive 
extension includes a clam-shell housing 143 having a primary support 
portion 143.1 and a cover 143.2. The housing parts 143 are in turn 
supported at their rear end by the common input shaft 54 and at an 
intermediate portion by the fixed shaft rod 65. To this end, at least one 
of the portions 143.1, 143.2 is provided with a suitable support bearing 
144. In order to have the leg-drive means of the first embodiment 
drivingly connected to the common input shaft a further sprocket 146 is 
mounted on the driven shaft 112 for rotation therewith and another 
sprocket 147 is secured to the common input shaft 54 in line for the 
sprocket 146. A chain 148 is passed over the sprockets 146 and 147 to 
cause shafts 112 and 54 to rotate together. 
An adjusting mechanism indicated generally at 150 (FIG. 2) is mounted on 
the forward end of each of the clam-shell portions 143.1 and 143.2 which 
may be used to hold the housing assembly 92 in various positions of 
angular adjustment two of which positions are illustrated in FIGS. 1 and 
16. The adjusting mechanisms 150 are identical with the adjusting 
mechanism 132 through 138 and cooperate with suitable apertures 152 in the 
first housing assembly 106.1 and 106.2, only the apertures in the 
clam-shell cover 106.2 being illustrated. 
Resistance Means--First Embodiment 
The resistance given to the rotation of shaft 54 which is caused by motion 
of either the right arm-drive means 56, the left arm-drive means 58, or 
the leg-drive means 60 (or any combination thereof), can be created in a 
number of ways. Thus, if the chair is to be used as a stationary 
exerciser, it is only necessary to connect an adjustable resistance device 
to the common shaft 54, such an adjustable resistance device being a disk 
and disk brake, which disk is driven by the shaft 54, a magnetic field 
device such as an electrical generator with a variable resistance load, an 
aerodynamic resistance device such as a fan, or any other such suitable 
device as may occur to those skilled in the art. In addition to such a 
resistance device, which are well known from stationary exercise bicycles, 
the present invention also contemplates applying resistance by providing a 
drive for propelling the wheelchair in a forward direction. 
One form of propulsion device is illustrated in the first embodiment and 
consists of right and left friction-wheel drives 154, 156, respectively, 
which engage the rubber tread on the right and left drive wheels 16, 18, 
respectively, of the wheelchair. The right and left friction drive wheels 
154, 156 are in turn mounted on the ends of right-hand and left-hand 
output drive shafts 158, 160, respectively. The shafts 158 and 160 in turn 
extend outwardly from an intermediate differential 162. The differential 
is in turn driven through an input gear 164 which is in turn driven from 
the output gear 166 of a change-gear transmission 168. The transmission 
168 is of the type typically found in three-speed bicycles and will 
provide three or more output speeds, the speed being selected by shift 
lever 169. The transmission is driven by an input shaft 170 and when the 
shaft 170 is caused to be rotated in one direction, for example a 
counterclockwise direction when viewed from the left side, as shown in 
FIG. 1, the output gear 166 will be driven. However, the transmission 168 
is of the type that will free wheel. Thus, when the shaft 170 is rotated 
in an opposite direction, for example clockwise as shown in FIG. 1, there 
will be no output to the gear 166 as a one-way or overrunning clutch 
mechanism is employed within the transmission 168. The input shaft 170 is 
in turn caused to be driven by a sprocket and chain mechanism including 
chain 172 and input and output sprockets 174, 176, respectively. The input 
sprocket 174 is secured to the common shaft 54 for rotation therewith. 
Similarly, the sprocket 176 is secured to the input shaft 170 of the 
transmission for rotation therewith. 
Lateral Transfer 
It is a feature of the present invention that the exercising attachment can 
be mounted on the wheelchair without affecting normal lateral transfer of 
the user to or from the wheelchair. To accomplish this the housing 92 and 
the foot pedals 98 must be stowed underneath the wheelchair. One of the 
lever assemblies 72, 74 must be split with the upper portion 72 being 
placed in a stowed position. Finally, it will be necessary to move an arm 
rest 38 also to a position where it will not affect lateral movement of 
the user. These various positions are shown in FIG. 16. After a user of 
the wheelchair has transferred onto the wheelchair, it is then necessary 
to properly reposition the various parts. This is done simply by raising 
and swinging the arm rest 38 to its forward position and then forcing it 
down so that it will be held in its forward position. The upper tubular 
intermediate portion 72.2 will then be telescoped about the lower 
intermediate portion 74.2 and the housing 92 will be swung to its normal 
operating position and pinned in place, the pedals 98 then being properly 
positioned. If the user has leg mobility, he will then place his feet upon 
the pedals. If necessary the user's feet can be secured onto sole plates 
100 by toe and heel clips. The handgrips 72.1 will be engaged and, if they 
are in an intermediate position, as for example the positions shown in 
FIGS. 3b and 3d, it is only necessary to pull on one of the handgrips to 
initiate forward movement of the wheelchair. This movement will be 
transmitted to the pedals and provide proper exercise to the lower limbs 
in the case of a patient not having movement of the lower limbs. 
Alternatively, if the patient has movement of the lower limbs, coordinated 
movement between the arms and legs is achieved as all motions are commonly 
transmitted through the common input shaft 54. The gearing is so selected 
that either synchronous or asynchronous bilateral movement may be 
achieved. While the resistance means shown in FIGS. 1 through 16 is the 
resistance imparted by forward motion, in some cases it may be desirable 
to use the apparatus of this invention in a stationary manner. To this end 
the handgrips will be reciprocated initially in a backwards manner as well 
as the pedals 98. As a transmission 168 utilized has an overrunning clutch 
mechanism, this motion will not impart any forward motion to the 
wheelchair and suitable resistance means of the type typically used with 
stationary exercise bicycles may be employed. Thus, a disk may be mounted 
on the shaft 54 which can be engaged by a suitable caliper brake, or any 
other suitable mechanism, including air resistance means, may be employed 
to provide a suitable resistive effort to the operation of the pedals and 
handgrips. 
Steering Brakes Mounting--First Embodiment 
In the first embodiment, the caliper brake mechanisms 86 are pivotally 
mounted on eye bolts 182 which are suitably secured to the lower end of 
each of the right and left plates 64. If one desires to turn in the 
right-hand direction, it is only necessary to engage the right-hand 
pivoted lever 84 to cause the right-hand caliper brake to engage the 
right-hand drive wheel 16. The force imparted from the drive shaft 54 will 
now pass through the differential 162 and drive the other wheel at a 
faster rate than the one being braked to affect a turning motion. 
Second Embodiment 
While some differences between the first and second embodiments have been 
discussed above, the second embodiment of FIGS. 17 through 21 differs from 
the first embodiment primarily in the manner in which the wheelchair may 
be driven to impart a resistance to the turning of the input shaft 54. 
Thus, in the second embodiment the propulsion means which imparts a 
resistance is a fifth wheel 184, the fifth wheel trailing under the chair. 
The fifth wheel is mounted upon a transmission 186 in the same manner that 
a bicycle wheel is mounted on its hub transmission. The transmission is in 
turn supported by stub shafts 188 in turn received by slotted ends of a 
fork 190. The transmission 186 controlled by a conventional Bowden wire 
mechanism 192, the upper controlling shift lever mechanism not being 
illustrated in FIGS. 17 through 19. The transmission 186 may also include 
an overrunning clutch to permit the pedals or hand levers to be moved in 
an opposite direction without imparting a forward motion to the fifth 
wheel 184. The axis for the fifth wheel 184 is indicated by the broken 
line 194 in FIG. 18. In order to prevent scuffing of the fifth wheel 184 
during turns, it is desirable that the axis 194 be in line with the axis 
196 of the rear wheels 16, 18 when viewed from above as shown in FIG. 16. 
The fork 190 is the rear portion of a rear trailing arm assembly or 
housing, indicated generally at 198, which is of a dog-leg shape. Its 
upper forward end portion 200 is journaled for pivotal motion about the 
common input shaft 54. The means for imparting rotary motion to the fifth 
wheel include a sprocket 202 secured the shaft 54, an intermediate shaft 
204, a pair of sprockets 206 and 208 carried by the intermediate shaft 204 
for rotation therewith, and one more sprocket 210 suitably connected with 
the input shaft of transmission 186 to act as the input therefore. When 
the shaft 54 is rotated, it will cause corresponding rotation of the 
sprocket 202, which will in turn cause sprockets 206 to rotate due to the 
provision of a chain 212. The chain 212 is suitably tensioned by a tension 
idler 214 Finally, a further chain 216 is provided which is driven by 
sprocket 208 the chain in turn driving sprocket 210. It is not necessary 
to provide a chain tension idler for this chain as the tension on the 
chain 216 can be suitably adjusted by moving the sprocket 210, along with 
transmission 186 towards and away from the shaft 214 within the slots of 
the fork ends. 
Biasing means indicated generally at 218 are provided to ensure that the 
fifth wheel 184 engages the surface of the ground with sufficient force to 
propel the chair in a forward direction. The biasing means includes an eye 
bolt 220 or the like which has its eye end disposed about a stub shaft 222 
between the forks of the rear portion 190 of the trailing arm assembly 
198. This shaft is positioned just forwardly of the fifth wheel 184 as can 
best be seen in FIG. 18. The upper end of the eye bolt 220 passes through 
a frame member or bracket 224, the ends of which are secured to the plates 
64.1 and 64.2. A washer or the like 226 is provided on an intermediate 
portion of the eye bolt between the frame member 224 and the shaft 220 and 
a spring 228 is provided above the washer 226, which spring wears against 
the washer 226 and the frame member 224 to force the rear trailing arm 
assembly downwardly. The washer may be held in position by a sleeve 229. A 
torsional spring, around the drive shaft, could be used instead of this 
type of "suspension". 
The operation of the second embodiment is essentially the same as the 
operation of the first embodiment. The mounting of the chain housing 92 to 
the shaft 54 differs as has been previously indicated, and it is 
adjustably positioned by means of a long bolt 230 which passes through 
suitable apertures 232 in the upper forward end of the upper forward 
portion 200 and corresponding aperture 234 in the first housing assembly 
106. The second embodiment does not show the sole plates 100, merely 
showing right and left pedals 98.1, 98.2. However, if the user of the 
wheelchairs needs or requires such sole plates with the heel and toe 
clips, they can be readily added to the pedals shown. In the second 
embodiment the lever mounting assembly 76 is moved forwardly of the 
location shown in the first embodiment to provide better ergonomics. The 
second embodiment also differs from the first embodiment in that the brake 
caliper 86 is carried by a bracket 236 which is in turn secured to a lower 
portion 20.4 or 22.4 of the frame assembly. 
It has been found through testing that the embodiment illustrated in FIG. 1 
provides greater resistance to the turning of the input shaft 54 than the 
design shown in the second embodiment. This is believed to be due 
primarily to the inefficiencies of the friction-wheel drives 154, 156. 
Also, as the drive is more complicated, there are the inefficiencies of a 
more complicated drive mechanism. Thus, it has been found in many 
situations that the vehicle shown in the first embodiment need not be 
provided with any further resistance means when utilized in a stationary 
manner. It has also been found that the version shown in FIGS. 17 through 
19 is also suitable for relatively rapid movement from one location to 
another, particularly for those who have use of their legs. Thus, when the 
attachment shown in the second embodiment has been mounted on a standard 
wheelchair, it has been possible for an average male college student to 
maintain speeds in the neighborhood of 10 miles per hour with very little 
(or minimal) effort. In order to reduce the added weight of the 
attachments, suitable low weight materials are utilized. 
Finally, the present apparatus may also be utilized with functional 
electrical stimulation, if desired. 
While two preferred forms of the present invention have been illustrated 
and described above, it should be apparent that various modifications may 
be made. Accordingly, applicant does not intend to be limited to the 
particular details shown and described above, but that, it will be 
understood that the foregoing description and illustrations are by way of 
example only, and that such modifications and changes as may suggest 
themselves to those skilled in the art are intended to fall within the 
scope of the present invention as defined by the appended claims.