U.S. patent number 3,888,463 [Application Number 05/389,463] was granted by the patent office on 1975-06-10 for self-leveling hoist for wheel chairs.
Invention is credited to Robert A. O'Brien, Manuel Peterson.
United States Patent |
3,888,463 |
O'Brien , et al. |
June 10, 1975 |
Self-leveling hoist for wheel chairs
Abstract
A hoist having a mobile frame, a pair of supports mounted on the
frame, an arm mounted for pivotal movement on each support, a
platform secured on the remote ends of the arms, a ram
interconnecting each support and its respective arm for elevational
movement in parallelism, and a power system mounted in driving
relation to the rams.
Inventors: |
O'Brien; Robert A. (Fresno,
CA), Peterson; Manuel (Fresno, CA) |
Family
ID: |
23538368 |
Appl.
No.: |
05/389,463 |
Filed: |
August 20, 1973 |
Current U.S.
Class: |
254/10C; 212/195;
254/129; 212/261; 414/921; 187/900 |
Current CPC
Class: |
A61G
3/063 (20130101); B66B 9/00 (20130101); B60P
1/48 (20130101); Y10S 187/90 (20130101); Y10S
414/134 (20130101) |
Current International
Class: |
B66B
9/00 (20060101); A61G 3/06 (20060101); B60P
1/00 (20060101); A61G 3/00 (20060101); B60P
1/48 (20060101); B60p 001/48 () |
Field of
Search: |
;212/8A,9
;254/1R,1B,1C,124,129 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Reeves; Robert B.
Assistant Examiner: Scherbel; David A.
Attorney, Agent or Firm: Huebner & Worrel
Claims
Having described our invention, what we claim as new and desire to
secure by Letters Patent is;
1. A wheel chair hoist comprising a mobile frame, elongated support
means mounted on the frame and upwardly extended therefrom, bracket
means mounted on the support means for elevational adjustment,
means for securing the bracket means in adjusted position on the
support means, a wheel chair platform having oppositely disposed
open ends and a path of wheel chair travel between the open ends,
substantially parallel arms pivotally connected to the bracket
means and to the platform on opposite sides of the path mounting
the platform on the frame at one side of the support means for
concurrent longitudinal reciprocal movement and adjustable
elevational movement in parallelism, powered means interconnecting
the bracket means and the arms to raise and to lower the platform
on the frame, and a counterbalance mounted on the bracket means on
the opposite side of the support means from the platform for
integral elevational adjustment with the bracket means.
2. A wheel chair hoist comprising a mobile support frame having
predetermined forward and rearward end portions; a pair of spaced
support members rigidly mounted on the support frame adjacent to
the forward end portion and upwardly extended therefrom; brackets
mounted on the support members for corresponding adjustable
elevational movement; a pair of elevationally spaced substantially
parallel arms pivotally mounted on each bracket and rearwardly
extended therefrom for pivotal elevational movement as well as
adjustable elevational movement with their respective bracket; an
elongated platform having opposite ends both adapted to receive and
to discharge a wheel chair for rolling movement longitudinally
across the platform pivotally mounted between the rearward ends of
the arms for elevational movement therewith in horizontal
parallelism; powered means connected to the arms for controlled
raising of the arms to move the platform upwardly and forwardly for
juxtaposition with an elevated surface to and from which a wheel
chair can be rolled and controlled lowering of the arms to move the
platform downwardly and rearwardly from the elevated surface to a
lower surface to and from which a wheel chair can be rolled; and a
counterbalance interconnecting the brackets for corresponding
elevational movement therewith at the side thereof opposite to the
direction of arm extension from the brackets.
3. The hoist of claim 2 in which the counterbalance has a
substantially flat upwardly disposed surface intermediate the
raised and lowered positions of the platform.
4. The hoist of claim 2 in which the powered means includes
hydraulic rams connected to the brackets and having position
controlling connection to the arms and in which the counterbalance
includes a container containing an hydraulic system connected to
the rams, an electric motor having powering connection to the
hydraulic system, and a battery having powering connection to the
motor whereby the hoist is self contained and the powered means is
elevationally adjustable with the arms in response to elevational
adjustment of the brackets on the support members.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a self-contained hoist and more
particularly to such a hoist which is capable of being operated and
maintained by a disabled person for purposes of gaining access to
elevated areas.
Lifting devices are employed in a multitude of areas of
application. Such devices commonly require permanent implacement at
a specific location and are dependent upon external sources of
power for their operation. This is particularly onerous for
disabled persons such as paraplegics and paralytics borne by wheel
chairs who must use such lifting devices to gain entrance to
elevated areas which are otherwise inaccessible. Disabled persons
normally depend upon others to mount the device in position for use
and frequently must rely upon others to operate and maintain the
device. This dependence and the attendant embarrassment discourages
the use of such devices.
Furthermore, the dependence upon external sources of power severely
limits the locations at which such devices may be employed. Thus,
gaining entrance to automobiles, buses, trains, aircraft, mobile
homes, buildings and the like becomes difficult to the point of
practical impossibility. Because of these deficiencies, disabled
persons are dissuaded from exposing themselves to situations in
which such dependence upon a lifting device as well as other
persons would be required.
Therefore, it has long been recognized that it would be desirable
to have a hoist which can be operated and maintained by disabled
persons without dependence upon others thereby encouraging the
mobility and self-reliance of such persons.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention
to provide an improved self-contained hoist.
Another object is to provide such a hoist which does not require
permanent or semipermanent implacement prior to use.
Another object is to provide such a hoist which may easily be
motivated to any suitable location for use.
Another object is to provide such a hoist which is adapted to be
operated solely by a disabled person to elevate himself.
Another object is to provide such a hoist which can be maintained
by disabled persons.
Another object is to provide such a hoist which is not dependent
upon external sources of energy for its operation.
A further object is to provide such a hoist which is balanced so as
to remain stable during operation.
Further objects and advantages are to provide improved elements and
arrangements thereof in a device for the purposes described which
is dependable, economical, durable and fully effective in
accomplishing its intended purposes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the self-contained hoist of the
present invention.
FIG. 2 is a top plan view of the hoist.
FIG. 3 is a side elevation of the hoist.
FIG. 4 is an end view of the hoist.
FIG. 5 is a somewhat enlarged fragmentary vertical section taken on
line 5--5 in FIG. 2.
FIG. 6 is a fragmentary top plan view of the portion of the hoist
viewed in FIG. 5.
FIG. 7 is a schematic illustration of the power system for the
hoist.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring more particularly to the drawings, the selfcontained
hoist of the present invention is generally indicated by the
numeral 10. As shown in FIG. 1, the hoist is adapted to support a
wheel chair 11 shown in dashed lines in FIG. 1. The hoist is
adapted to be positioned in rested relation on a floor or ground
surface generally indicated by numeral 12 in FIGS. 3 and 4. As
shown in FIG. 3, the hoist is positioned in its normal operational
environment adjacent to a floor 13 shown in dashed lines.
The hoist 10 has a substantially rectangular frame 20 composed of a
pair of spaced, substantially parallel angle-iron bars 21 having
opposite ends 22. The bars are interconnected at their
corresponding opposite ends by a pair of substantially flat cross
plates 23. A pair of support members 24, having remote ends 25 are
individually secured, as by welding, adjacent to corresponding
opposite ends of the angle iron bars in substantial right angular
relation. A ground wheel assembly 26 is secured, as by welding, on
each support member immediately adjacent to the opposite end of its
respective angle-iron bar, as best shown in FIG. 3.
A bracket or mounting assembly 35 is slidably mounted on each of
the support members 24. Each of the mounting assemblies has a
tubular sleeve 36, having a front side 37 and a back side 38,
slidably received on its respective support member. The back side
of each sleeve has a pair of screw threaded bores 39. A bolt 40 is
screw threadably received in each of the bores and adapted to be
tightened into binding engagement with its respective support
member so as to secure the sleeve in position. A pivotal connection
41 is fastened on the back side of each tubular sleeve, as best
shown in FIGS. 5 and 6. A cross member 42 is affixed on the sleeves
in interconnecting relation substantially normal to the support
members.
Each of the mounting assemblies 35 has a mount 46 secured for
pivotal movement on its respective pivotal connection 41. Each of
the mounts has a pair of substantially flat side plates 47
interconnected by a stop plate 48 extending substantially normal to
and between the side plates. Each of the side plates has an
integral pivot arm 49 extending from its respective support member
to the left, as viewed in FIG. 3, and an oppositely extending ram
arm 50. The pivot arms of each mount are secured for pivotal
movement on the pivotal connection of their respective tubular
sleeve 36. A screw threaded bore 51 is extended through the stop
plate of each mount and has an adjustment bolt 52 screw threadably
received therein for engagement with the front side 37 of the
tubular sleeve.
As best shown in FIGS. 5 and 6, each of the mounts 46 has an upper
pivotal connection 60 extending between the side plates 47 thereof
substantially right angularly thereto. A lower pivotal connection
61 extends between the side plates in spaced relation to the upper
pivotal connection. A ram connection 62 extends between the ram
arms 50 of the side plates of each mount. A normally closed limit
switch 63 is adjustably mounted on the ram connection of one of the
mounts. The switch has a switch lever 64 operably mounted
thereon.
A pair of adjustable braces 70 are extended between the frame 20
and each of the mounting assemblies 35. Each brace has a rigid tube
71 pivotally secured outwardly on each of the angleiron bars 21
intermediate the opposite ends 22 thereof, as best shown in FIGS.
1, 3, and 4. Each of the tubes has an adjustment nut 72
rotationally mounted at the end thereof remote from the frame. A
screw-threaded eye bolt 73 is pivotally mounted on each of the
pivotal connections 41 outwardly of its respective mount 46 and
adjustably screw-threadably received in the adjustment nut of its
respective tube, as best shown in FIG. 6.
An arm assembly 80 is mounted on each of the mounting assemblies 35
in alignment with its adjacent angle-iron bar 21. Each of the arm
assemblies has a lower arm member 81, having opposite ends 82,
pivotally fastened adjacent to one of its opposite ends on the
lower pivotal connection 61. Each arm assembly has a pair of upper
arm members 83, having opposite ends 84, individually pivotally
mounted on the upper pivotal connection 60 of each mounting
assembly. A ram 85, having an extendible power arm 86, is pivotally
mounted on the ram connection 62 of each mount 46. A pivotal
connection 87 is affixed on each of the lower arm members adjacent
to the opposite end thereof remote from its respective mounting
assembly. The power arm of each ram is connected to the pivotal
connection 87 of its respective arm assembly, as best shown in FIG.
3.
A platform 94 is mounted on the remote ends of the arm assemblies
80. The platform has opposite sides 95 and has a pair of spaced,
substantially parallel inverted channel members 96. Four
substantially parallel cross plates 97 are secured on the channel
members extending substantially right angularly thereto. A floor 98
is fastened, as by welding, on the channel members and cross plates
in supported relation. The floor has a pair of wheel depressions 99
integrally formed therein, as best shown in FIG. 2. A pair of
upstanding side rails 100 are mounted on the floor in spaced
relation in substantial alignment with their respective adjacent
channel members. A conduit 101 is fastened on each of the side
rails extending to the floor substantially normal thereto.
A return bent mount 109 is secured, as by welding, on the cross
plates 97 adjacent to each of the channel members 96 midway between
the opposite ends thereof. Each mount has an upper pivotal
connection 110 and a lower pivotal connection 111 disposed
substantially right angularly to their respective channel members.
The pivotal connections 110 and 111 of each mount are axially
aligned with their corresponding respective pivotal connections of
the other mount. The ends 82 of the lower arm members 81 remote
from the arm mounting assemblies 35 are pivotally connected to
their respective lower pivotal connections 111. Similarly, the
remote opposite ends 84 of the pair of upper arm members 83 are
pivotally connected to their respective upper pivotal connections
110. The upper arm members and lower arm member of each arm
assembly thereby form a parallelogram type linkage so as to support
the platform 94 for movement in parallelism on the frame 20, as
best shown in FIG. 3. An elongated box-like container 112 is
mounted, as by welding, on the cross member 42 between the mounting
assemblies 35. The container has an internal receptacle 113 and
affords a cover 114 which is removable from the container to gain
access to the receptacle.
As shown in dashed lines in FIG. 2, the receptacle of the container
has a power source generally indicated by numeral 119 mounted
therein. The power source includes a fluid circulating system
generally indicated by the numeral 120, as schematically
illustrated in FIG. 7. The system is preferably hydraulic so as to
insure a smoothness of operation. The system includes a fluid
reservoir 121 which is mounted within the receptacle 113 of the
container 112, as shown in FIG. 2. The fluid reservoir contains a
conventional hydraulic fluid. The system further includes a fluid
pump 122, a return valve 123 and a regulator valve 124 all of which
are similarly mounted in the receptacle of the container, as shown
in dashed lines in FIG. 2. A pump conduit 125 interconnects the
reservoir and the pump in fluid transferring relation. A supply
conduit 126 is extended from the fluid pump in fluid transferring
relation. A pair of flexible ram hoses 127 are extended from the
remote end of the supply conduit and are individually connected in
fluid transferring relation to the rams 85 adjacent to their
respective power arms 86 in the conventional manner. A return
conduit 128 is connected to the supply conduit in fluid
transferring relation and is operably extended through the return
valve 123, the regulator valve 124 and connected to the fluid
reservoir 121.
The power source 119 further includes an electrical drive system
schematically illustrated in FIG. 7 and generally indicated by the
numeral 135. The electrical system has a pump motor 136 mounted in
driving relation to the pump 122. The electrical system further
includes a battery 137, and a charger 138 having an electrical
connection 139 adapted for insertion in a conventional wall socket,
not shown. The battery and charger are mounted in the receptacle
133 of the container 112. A solenoid 140 is mounted in operable
connection with the return valve 123 and adapted to maintain the
valve in a closed configuration when the solenoid is not energized.
A platform control mechanism or switch box 141 is mounted on the
side rail 100 on the left as viewed in FIG. 4. The box operably
mounts a spring loaded, normally open platform lifting switch 142
and a similarly spring loaded, normally open platform lowering
switch 143.
The electrical system 135 has an electrical circuit 151. The
circuit includes a first motor conductor 152 electrically
interconnecting the battery 137 and the motor 136. A second motor
conductor 153 extends from the motor and is in turn connected to
the limit switch 63. A lifting switch conductor 154 interconnects
the limit switch and the lifting switch 142. A return conductor 155
interconnects the lifting switch and the battery.
The electrical circuit 151 further includes a lowering switch
conductor 160 which interconnects the first motor conductor 152 and
the lowering switch 143. A first solenoid conductor 161
interconnects the lowering switch and the solenoid 140. A second
solenoid conductor 162 interconnects the solenoid and the return
conductor 155. A first charger conductor 163 interconnects the
charger 138 and the return conductor 155. A second charger
conductor 164 is extended from the charger to a normally open
control switch 165. A third charger conductor 166 operably
interconnects the control switch and the first motor conductor 151.
Conductors 154, 155, 160 and 161 extend through the conduit 101 of
the side rail 100 mounting the control box 141 for connection to
their respective lifting switch 141 and lowering switch 143, as
best shown in FIG. 5.
OPERATION
The operation of the described embodiment of the subject invention
is believed to be clearly apparent and is briefly summarized at
this point. The hoist 10 can be transported along the ground
surface 12 on its wheel assemblies 26 to the desired location for
use by grasping the cross plate 23 farthest from the support
members 24 so as to tilt the hoist back on the wheel assemblies.
This can frequently be accomplished even by a disabled person in a
wheel chair 11 due to the optimum distribution of weight relative
to the wheel assemblies by the mounting of the platform 94 and
container 112 on opposite sides of the support members 24. The
hoist is normally positioned with the container 112 disposed
beneath the floor 13 to which access is sought, as shown in FIG. 3.
With the frame 20 in rested engagement with the ground surface, the
hoist is in quite stable attitude for the performance of a variety
of lifting operations.
Normally adjustment of the elevation of the mounting assemblies 35
on the support members 24 is not required due to the capability of
selectively positioning the platform 94, as will subsequently be
described. However, where such adjustment is desired, the bolts 40
of each tubular sleeve 36 are first loosened. The adjustment nut 72
of each adjustable brace 70 is then adjusted so as to extend or
retract the eye bolt 73. The mounts 46 are accordingly adjusted on
their respective support members 24 as desired. When the desired
position has been selected, the bolts 40 are again tightened in
their respective screw threaded bores 39, and against the support
member securely to retain their respective mount 46 in the selected
position. The limit switch 63 is then adjusted on its respective
ram connection relative to the adjacent upper arm member 83 to
define a maximum elevation for the platform, as will subsequently
become more clearly apparent.
The hoist 10 is then operated to motivate the platform 94 to a
lowered position in engagement with the frame 20. A disabled person
desiring to use the hoist rolls the wheel chair 11 on which he is
seated onto the platform and positions the chair so that it is
securely received in the wheel depressions 99 of the floor 98. The
wheel chair is preferably oriented so that the person is facing in
the direction of the container 112. The lifting switch 142 is
subsequently pressed against spring tension and retained in this
position for as long as upward movement of the platform is desired.
As shown schematically in FIG. 7, closing of the lifting switch
completes the electrical circuit 151 from the battery 137, through
the first motor conductor 152 to the motor 136, from the motor
through the second motor conductor 153 to the limit switch 63, from
the limit switch through the lifting switch conductor 154 to the
lifting switch, and subsequently through the return conductor 155
to the battery.
Thus, electrical energy is supplied to the motor 136 which in turn
operates the pump 122. Accordingly, fluid, preferably hydraulic, is
pumped from the fluid reservoir 121 through the pump conduit 125,
the supply conduit 126, the ram hoses 127 and subsequently into the
rams 85. As a result the power arms 86 of the rams are gradually
and smoothly retracted. This contraction, as can best be seen in
FIG. 3, causes the lower arm member 81 of each arm assembly 80 to
be upwardly pivoted about the lower pivotal connection 61 thereof.
The parallelogram type linkage of the upper arm members 83 and
lower arm members 81 insures that the platform 94 is, as a result,
elevated under hydraulic power with the platform disposed parallel
to the frame, or, in other words, horizontally.
When the arm assemblies 80 reach the preselected elevated position,
the switch lever 64 of the limit switch 63 is contacted by its
adjacent upper arm member 83 so as to trip the limit switch and
open the electrical circuit 151. This terminates the flow of
electricala energy through the motor 136 so as to stop the
introduction of hydraulic fluid to the rams. Thus, the platform's
upward movement is discontinued. The platform 94 is retained in the
elevated position since fluid cannot return to the reservoir
through the supply conduit 126 or return conduit 128. The operator
can alternatively, of course, stop upward movement before the limit
switch 63 is tripped by simply releasing the lifting switch 142 and
allowing spring tension to again open the electrical circuit at
that point. However, normally the hoist is adjusted so that the
upper arm member trips the switch lever 64 at the time the floor 13
is reached by the platform.
After the switch lever 64 is tripped, the operator releases the
lifting switch 142 to allow the electrical circuit 151 again to be
broken. Subsequently the operator simply motivates the wheel chair
11 off the floor 98 of the platform 94 and onto the floor 13. As
long as the return valve 123 remains closed, the rams 85 remain in
their contracted configuration so as to maintain the platform at
the selected elevated level.
To transfer from the floor 13 to the ground surface 12, the
operator simply rolls the wheel chair 11 onto the platform 94.
Subsequently the lowering switch 143 is pressed against spring
tension to complete a portion of the electrical circuit 151. The
portion of the circuit completed extends from the battery 137
through the first motor conductor 152, through the lowering switch
conductor 160 to the lowering switch, through the first solenoid
conductor 161 to the solenoid 140, through the second solenoid
conductor 162 to the return conductor 155 and back to the battery.
Thus the solenoid is energized to open the return valve 123 thereby
allowing hydraulic fluid to be discharged under pressure through
the ram hoses 127, the supply conduit 126, and the return conduit
128 to the reservoir 121. The regulator valve 124 insures that the
flow of hydraulic fluid is maintained at a constant, relatively
slow rate of speed so that the platform is lowered slowly and
evenly.
When the platform reaches the desired lowered position, the
lowering switch 143 is released to again allow spring tension to
open the portion of the electrical circuit 151 through the solenoid
140. As a result, the return valve 123 again closes to terminate
the flow of fluid back to the reservoir 121 and retain the platform
94 in the desired position. The operator then simply rolls the
wheel chair 11 from the platform as desired.
It will be noted that the hoist 10 of the present invention is
entirely self-contained not being dependent upon any outside source
of energy. The charger 138, with its associated electrical
connection 139, is adapted to permit charging of the battery 137
when convenient by insertion of the electrical connection into a
conventional electrical wall outlet, not shown. When the control
switch 165 is manually closed, electrical energy is allowed to flow
through the connection to the charger which, in the conventional
manner produces the proper electrical voltage required for charging
the battery. This energy is transmitted through the battery by the
charger conductors 163, 164 and 166. Disabled persons can readily
perform such a charging operation as well as otherwise maintaining
the hoist. Thus, the container 112 is at a convenient heighth for
servicing the battery and other elements contained therein from a
wheel chair.
Therefore, the hoist of the present invention is entirely
self-contained not being dependent upon any outside source of
energy nor requiring permanent or semipermanent installation prior
to use. Furthermore, the hoist is adapted readily to be adjusted,
operated and maintained even by disabled persons without dependence
on other persons thereby encouraging mobility and
self-reliance.
Although the invention has been herein shown and described in what
is conceived to be the most practical and preferred embodiment, it
is recognized that departures may be made therefrom within the
scope of the invention, which is not to be limited to the
illustrative details disclosed.
* * * * *