US3638813A

US3638813A - Wheelchair lifting device

Info

Publication number: US3638813A
Application number: US879651A
Authority: US
Inventors: John H Strong
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-11-25
Filing date: 1969-11-25
Publication date: 1972-02-01
Anticipated expiration: 1989-02-01

Abstract

A chair lift having a mount, lifting arms supporting a chair platform, and horizontal swivel arms for rotating the chair platform about the mount, a power supply and electrical circuitry being provided for controlling hydraulic pressure in cylinders connected to move the lifting and swivel arms.

Description

0 United States Patent 1 3,638,813 Strong 1 1 Feb. 1, 1972 [54] WHEELCHAIR LIFTING DEVICE 3,458,073 7/1969 Dawson ..214/450 3,476,404 11/1969 Rachman.. ....2I4/l A Inventor: J g, 9 10 h Sacra- 3,516,559 6/1970 Walter ....214/730 mento, Calif. 95816 lrene Strong, Sacra- 3,532,238 10/1970 McMillan ..2l4/67] mento, California, surviving wife and benificiary under the Last Will and Testament of said John H. Strong, deceased. Primary Examiner-Gerald M. Forlenza Assistant Examiner-John Mannix [22] Attorney-Alexander 8. Blair [21] Appl. N0.: 879,651

[ ABSTRACT A chair lift having a mount, lifting arms supporting a chair [52] U.S.Cl ..2l4/148,214/5333; platform, and horizontal Swivel arms for rotating the chair platform about the mount, a power supply and electrical cir- [51] [Ill-Cl ..B66C 23/00 cuitry being provided for controlling hydraulic Pressure in [58] Field of Search ..214/730, 671, 660, l A, 148, cylinders connected to move the lifti and Swive] 3mm 214/149, 77, DIG. 10

5 Claims, 3 Drawing Figures [56] References Cited UNITED STATES PATENTS 2,975,923 3/1961 Ulinski ..214/730 PATENTEBFEB H272 316351813 SHEET 10F 3 IN VEN TOR.

4/014 H STRONG BY PATENTEU m H972 3.633.313

1N VEN TOR. Jay/v A. 57k0/V6 A TTORNEY.

INVENTOR.

JOHN H. STRONG BY WHEELCHAIR LIFTING DEVICE This invention relates to a self-operated wheelchair lift. At the present time there is not way for a wheelchair patient, without assistance, to roll his chair out the front door of his home down the usual three or four steps of the front stoop of the house, to get from one level to a slightly higher level ofa split-level home, to board a plane, etc. This invention will alleviate these problems and when installed will serve many other purposes also. For instance, the device may be installed near a ground floor, kickout type of emergency window in convalescent homes and hospitals which would permit wheelchair patients to get out of buildings unassisted in the event of fire or other emergencies. This invention allows the wheelchair patient to raise, tilt, and rotate the wheelchair in which he is sitting safely and efficiently in order to get from one place to another without aid.

Accordingly, a primary object of this invention is to provide a platform for safely carrying the wheelchair from one place to another.

Another object of this invention is to provide lifting and horizontal swivel arms which allow the wheelchair to be lifted and rotated to any position desired within range ofthe device.

A further object of this invention is to provide a hydraulic pressure source and electrical circuitry so that the wheelchair patient may control the lifting and horizontal swivel arms by himself without aid.

A still further object of this invention is to provide means for tilting the wheelchair platform in order to prevent the wheelchair from rolling off the platform while being lifted and carried.

The above and other objects of this invention will become apparent to those skilled in the art after a consideration of the following detailed description of the various forms of this invention taken together with the accompanying drawings, in which:

Flg. l is a plan view of the wheelchair lift illustrating the range of rotation from inside a building out through a double door;

FIG. 2 is an elevational sectional view taken on line 2-2 of FIG. 1 illustrating how the wheelchair is lifted, tilted, and lowered; and

FIG. 3 is a schematic diagram of the electrical control circuitry.

Referring to the drawing in greater detail, there is illustrated in FIGS. 1 and 2 a power unit connected to a mount 12 which is secured to the floor level by means of a plate 14. Pivotally attached to mount 12 are upper and lower

horizontal swivel arms

16, 16 which support at their ends a vertical post 18. A lower lifting arm 20 and an upper lifting arm 22 are pivotally connected at one end thereof to vertical post 18 and pivotally support at the other end the rear platform post 24 which is vertically secured at the bottom thereof to the rear of the wheelchair platform 26. Platform 26 has

cutouts

28, 28 at the rear and on each side thereof so that as a wheelchair 30 is rolled backward onto platform 26, the rear wheels 32 will roll into cutout 28 and will rest on the ground or floor being exposed beneath platform 26. Extending outward, as shown in FIG. 2, from a mount on rear platform post 24 are a pair of arms or adjustable chair stops 34 equipped with rubber guards 36 and a seatbelt 38.

A hydraulic cylinder 40 is pivotally connected between mount 12 and vertical post 18 with its ram end 42 pivotally attached to vertical post 18. FIG 1 illustrated how hydraulic pressure within cylinder 40 pushes out ram 42 thereby causing vertical post 18 to swing about mount 12 from the solid line position within a building to the dotted line position outside the building where ram 42 is shown extended outward.

A hydraulic lift cylinder 44 is pivotally connected between the bottom of vertical swing post 18 and upper lifting arm 22, its ram end 46 being attached to upper lifting arm 22. Hydraulic pressure forces ram 46 outward from its normal position causing upper lifting arm 22 to lift rear platform post 24 and wheelchair platform 26. At a predetermined height above floor level a link stop 48 will prevent further pivotal movement of lower lifting arm 20 in clockwise direction. At this point in time, an adjustable spring-operated friction clutch 50 secured to rear platform post 24 and upon which upper lifting arm 22 is pivotally attached, will move from the top of a slot 52 in upper lifting arm 22 where it was held by friction toward the bottom of slot 52 as upper lifting arm 22 continues to pivot in the clockwise direction. As upper lifting arm 22 moves upward past friction clutch 52, rear platform post 24 will be tilted about the pivot 54 of lower lifting arm 20 which is now in a fixed position because of link stop 48. As wheelchair platform 26 lifts and tilts, rear wheels 32 roll into platform cutouts 28 as shown by reference numeral 32 in FIG. 2 making it impossible for the wheelchair to roll off wheelchair platform 26. The tilt of rear platform post 24 and the clockwise movement of upper lifting arm 22 are terminated when upper lifting arm 22 makes physical contact with vertical swing post 18 in the position shown in FIG. 2 where upper lifting arm 22 is labeled 22'. When the wheelchair is to be lowered, hydraulic pressure will be withdrawn and applied to the ram end of cylinder 44 causing ram 46 to be lowered as will be explained later and in more detail. When the wheelchair is to be lowered to a height below floor level, hydraulic pressure is withdrawn and applied in the same manner causing upper and lower lifting arms 22 and 20 respectively to pivot in the counterclockwise direction lowering the wheelchair to the lower site, wheelchair platform 26 being lowered until ram 46 is completely lowered into hydraulic lift cylinder 44 or until lower lifting arm 20 makes contact with the edge of the upper level surface at point 56.

There is shown in FIG. 3 a reservoir 68, a pump 70, an elevation control 72 and a swing control 74. When the wheelchair is to be lifted, elevation control 72 is switched to the "up" contact. Current flows to control solenoid 76 which, upon actuation, opens a hydraulic valve 78 allowing pressure to enter hydraulic lift cylinder 44. When elevation control 72 close circuits with the up" contact, current will also pass through an isolation relay 80 which, upon actuation, close circuits contacts 82 and 84 sending the current to a 2-second delay vacuum tube 86. The current passes through a relay 88 and then actuates an electric motor control relay 90 to start pump 70 pumping hydraulic oil through line 92 which is connected to hydraulic valve 78. Control solenoid 76, having opened hydraulic valve 78 to line 92 and line 94, allows the hydraulic oil to pass through line 94 into the bottom of hydraulic lift cylinder 44 forcing ram 46 upward. When elevation control 72 is switched to the down" contact, current in the same manner as already described will pass to control sole noid 76 which will be actuated to open up hydraulic valve 78 to connect line 92 with the line 98. Current also passes through isolation relay 96, vacuum tube 86, relay 88, and electric motor control relay 90 actuating pump 70 to pump hydraulic oil through lines 92 and 98 which is connected to the top of hydraulic lift cylinder 44 so that the hydraulic oil forces ram 46 downward. Hydraulic oil pressure below ram 46 is withdrawn at the bottom of hydraulic lift cylinder 44 by means of line 94 and return line 100.

When the wheelchair is to be swung through a door opening, a swing control is switched to the right" contact allowing current to pass to a control solenoid 112 which, upon actuation, opens a hydraulic valve 114 connecting pressure line 92 with a pressure line 116. Current also passes through isolation relay 118, vacuum tube 86, relay 88, and electric motor control relay 90 actuating pump 70 which pumps hydraulic oil through line 92 and line 116 which is connected at the base of hydraulic swing cylinder 40 allowing hydraulic oil pressure to push ram 42 outward.

A door safety switch 120 connected in series with a tilt safety switch 122 prevents any swinging movement at any time except when doors 124 of FIG. 1 are in the open position and wheelchair platform 26 has been raised and tilted. Also, there may be another switch (not shown in the drawing) which automatically activates arms to extend outward from chair stops 34 in front of the wheelchair patient prior to lifting rather than using seatbelts 38 which manually have to be adjusted and put on and which would probably be neglected by wheelchair patients just as are automobile seatbelts.

When the wheelchair is to be swung back through doors I24, swing control 74 is switched to left" contact allowing current to flow to control solenoid l 12 which actuates hydraulic valve 114 to connect line 92 with the pressure line 126. Current also passes to isolation relay 128, vacuum tube 86, relay 88, and electric motor control relay 90 actuating pump 70 to pump hydraulic oil pressure through line 92 and line 126 which is connected at the front of hydraulic swing cylinder 40 so that hydraulic pressure will push ram 42 back into cylinder 40. Hydraulic pressure is withdrawn from the base of hydraulic swing cylinder 40 by means of lines H16 and 100.

It is possible to have a control swing from 45 to 180. A warning buzzer (not shown in the drawing) is actuated when the wheelchair is moving.

The uses of the wheelchair lifting device just described are numerous. For instance, many wheelchair patients are capable of operating motor vehicles with modified controls. This lift makes it possible for the individual to enter the vehicle, roll up to the drivers location, properly secure his chair, and drive unassisted. This device also in many cases eliminates hard to negotiate ramps. It gives freedom of movement and independence to wheelchair patients and eliminates a great amount of strain with regard to stairs in private homes.

Probably one of the most important implications of this device would be the facilitation of transportation of wheelchair patients in buses and small vans and also house trailers, recreational vehicles, and most other mobile vehicles. A switchbox 150 fixedly mounted on the wheelchair platform or supported by a flexible cable 152, as shown in FIG. 2, is connected to the control circuitry panel 148 on mount 12 so that the wheelchair patient may operate the device unassisted. Cable 152 may be of any length so that the wheelchair lifting device may be operated from any position or location necessary for practical use under the particular circumstances.

While the preferred embodiments of this invention have been illustrated and described, it will be understood by those skilled in the art that changes and modifications may be resorted to without departing from the spirit and scope of the invention.

it is claimed:

1. A wheelchair lifting device, comprising:

a mount;

first means pivotally connected to said mount for swinging thereabout;

a wheelchair platform;

second means pivotally connected to said first means and partially connected to said wheelchair platform for lifting and tilting said wheelchair platform, the tilt being about a horizontal axis;

a power source connected to said amount for activating said first means and said second means in the alternative;

a control circuit for actuating said power source;

said second means comprising a lower arm pivotally connected between said first means and said wheelchair platform;

an upper arm pivotally connected between said first means and said wheelchair platform and having a vertical slot at the end adjacent said wheelchair platform; and

a hydraulic cylinder pivotally connected to said first means at one end thereof and having a ram at the other end thereof pivotally connected to said upper arm, said ram, upon being activated by said power source, extending upward from and moving downward into said hydraulic valve, in the alternative, rotating said upper arm and said lower arm in a clockwise and a counterclockwise direction, in the alternative, about their respective pivot points located at said first means for respectively raising and lowering said wheelchair platform. 2. The wheelchair lifting device of claim 1 comprising a horizontal member extending from said wheelchair platform and protruding through the slot of said upper arm, said upper arm eing pivotally attached to said whee chair platform in a friction fit so that said horizontal member does not fall down to the bottom of the slot of said upper arm from the weight of said wheelchair platform, and a link stop adjacent said lower arm for terminating its upper clockwise movement at a predetermined height, said upper arm continuing clockwise movement after the termination of the clockwise movement of said lower arm causing said horizontal member to slide down to the bottom of the vertical slot of said upper arm allowing said wheelchair platform to pivot about its pivot point adjacent said lower arm.

3. A wheelchair lifting device, comprising:

a mount;

first means pivotally connected to said mount for swinging thereabout;

a wheelchair platform;

a power source connected to said mount for activating said first means and said second means in the alternative;

21 control circuit for actuating said power source;

said control circuit comprising first switch means;

a control solenoid;

a hydraulic valve connected between said control solenoid and said first means;

delay means;

said power source including a pump and a reservoir; and

pressure lines connected between said reservoir and said hydraulic valve and between said hydraulic valve and said first means, said first switch means connected in series with said control solenoid to open said hydraulic valve and also connected in series with said delay means and the pump of said power source for pumping oil pressure through said pressure line by means of the opened hydraulic valve to activate said first means.

4. The wheelchair device of claim 3, comprising second switch means connected between said first switch means and a door through which the wheelchair is to be moved, said second switch means connected to a door and closing circuit when the door is in the open position, and third switch means connected in series between said second switch means and said first switch means and closing circuit only after said second means has been activated.

5. The wheelchair device of claim 4, wherein said delay means comprises a plurality of relays and a vacuum tube connected in series between said first switch means and the pump of said power source.

Claims

1. A wheelchair lifting device, comprising: a mount; first means pivotally connected to said mount for swinging thereabout; a wheelchair platform; second means pivotally connected to said first means and partially connected to said wheelchair platform for lifting and tilting said wheelchair platform, the tilt being about a horizontal axis; a power source connected to said amount for activating said first means and said second means in the alternative; a control circuit for actuating said power source; said second means comprising a lower arm pivotally connected between said first means and said wheelchair platform; an upper arm pivotally connected between said first means and said wheelchair platform and having a vertical slot at the end adjacent said wheelchair platform; and a hydraulic cylinder pivotally connected to said first means at one end thereof and having a ram at the other end thereof pivotally connected to said upper arm, said ram, upon being activated by said power source, extending upward from and moving downward into said hydraulic valve, in the alternative, rotating said upper arm and said lower arm in a clockwise and a counterclockwise direction, in the alternative, about their respective pivot points located at said first means for respectively raising and lowering said wheelchair platform.

2. The wheelchair lifting device of claim 1 comprising a horizontal member extending from said wheelchair platform and protruding through the slot of said upper arm, said upper arm being pivotally attached to said wheelchair platform in a friction fit so that said horizontal member does not fall down to the bottom of the slot of said upper arm from the weight of said wheelchair platform, and a link stop adjacent said lower arm for terminating its upper clockwise movement at a predetermined height, said upper arm continuing clockwise movement after the termination of the clockwise movement of said lower arm causing said horizontal member to slide down to the bottom of the vertical slot of said upper arm allowing said wheelchair platform to pivot about its pivot point adjacent said lower arm.

3. A wheelchair lifting device, comprising: a mount; first means pivotally connected to said mount for swinging thereabout; a wheelchair platform; second means pivotally connected to said first means and partially connected to said wheelchair platform for lifting and tilting said wheelchair platform, the tilt being about a horizontal axis; a power source connected to said mount for activating said first means and said second means in the alternative; a control circuit for actuating said power source; said control circuit comprising first switch means; a control solenoid; a hydraulic valve connected between said control solenoid and said first means; delay means; said power source including a pump and a reservoir; and pressure lines connected between said reservoir and said hydraulic valve and between said hydraulic valve and said first means, said first switch means connected in series with said control solenoid to open said hydraulic valve and also connected in series with said delay means and the pump of said power source for pumping oil pressure through said pressure line by means of the opened hydraulic valve to activate said first means.