US 2892506 A
Description (OCR text may contain errors)
'June 30, 1959 Filed Jan. 15} 1957 J. A. SLATER 2,892,506 ELECTRICALLY DRIVEN INVALID CHAIR 2 Sheets-Sheet 1 Inventor JAMES A. 31/? T1272 June 30, 1959 J. A. SLATER ELECTRICALLY DRIVEN INVALID CHAIR 2 Sheets-Sheet 2 Filed Jan. 15, 1957 INYENTOR JAMES A. SLATER :ELECTRICALLY DRIVEN CHAIR .James A.' Slater, Eastleigh, England .;Application January 15, 1957, Serial No. 634,377
Claimspriority, application .Great Britain January 17, 1956 4 Claims. (Cl.180-26) i 'lhis invention'concerns invalid chairs and relates parjtiicularly to wheeled invalid chairs intended prinigrily' for indoor use.
fSeveral types of mechanically propelled invalid car- .riagesifor use out-of-doors are, of course, already known in the art, and as their prime movers, utilize either internal combustion engines or ,electric motors. JCarriages fpropelled by internal combustion engines are obviously F fundamentally unsuited for indoor use, While those elec- ,firically driven carriages which have been available hitherto,byreason of their steering constructions and drive arrangementsand their physical size together with" that of the-storage batteries required to operate the drive arrangements, have been of such unwieldy dimensions; and limited manoeuvrability as to be impracticable for use indoors in domestic premises.
'It is, therefore, an object of the invention to provide a highly manoeuvrable, mechanically propelled invalid chair suitable for indoor use and having dimensions of an order permitting it readily to negotiate paths between and around domestic furniture and the like.
According to the present invention, a mechanically propelled invalid chair includes a seat-carrying upright framework of which the height is commensurate with its width and length, a pair of non-driven spaced wheels supported or journalled in the base of said frameworkat or near to the rearward lateral edge thereof, a single driven ;wheel supported centrally of the lateral forward region of said framework, said wheel being adapted by way of steering means conveniently'accessible to a person'dis- 'posed on said seat,- to be rotated'at least through substantially a semicircle, and a front wheel drivingmotor mounted immediately adjacent said wheel in such a manner as to partake in the steeringrnovementsthereof.
The-chair is preferably constructed of tubular material, 'for example tubular-steel, and may conveniently comnprise. a cantilever chair-of the typecornmonly employed Z as .so-called nesting chairs. Such: achair presents a conzvenient base. for. mounting the aforementioned wheels, aand between thisbaseand zthe seat-carrying portionprodes ample space for mounting anelect-ric motorg'steerning imeansand;storage batteries. The springing action not ethe cantilever type of chair-is also aldesirable'feature.
--.The. steering @means preferably comprises a: substan- .-tially upright steering column terminatingnat azlheight .;to;be grasped by-a person seated ,in-the chair-anddetachably connectable with abox pivotally secured to a transgorse member extendingbetween the lateral'forward ex- .trernities of the framework-and'housing said motor, said .,box .at' the same time. presenting journal he lingseorl the ll k6 supports for the; front Wheel.
' -Th8 invention will. be described furtheigaby way of example, with reference to the accompanying drawings,
fig. l is a perspectiveelevation'of one invalid, chair ,.const ructed in-accordance with the invention,
Fig. 2,.is, a diagrammatic -sectional;elevation-;,of the rg whes td v .an s ee in arran ement .;2 t Fig. 3 is a detail-of a steeringcolumn used to steer-and control the arrangement of Fig; 2,
Fig. 4 is a detail in perspective showing therear wheels suspension and battery-carrying arrangement,
"Fig. 5 is a schematic circuit diagram of the, drivejilnd control arrangements for the chair, and
"rotatable within this collar 5- there' engages a-smaller diameter tubular stub 6 projecting from-or securedto the upper face of a box housing 7, at a lower region of Fig. 6 is a front view from the chair side of thesteeringhandle, partially broken away,- to show the electrical switch means contained therein.
- In the embodiment of the invention shown in the drawings, between the forward, upright laterally-spacedframe portions 1a, 1b of a cantilever chair 2 of tubular steel construction, there extends a transverse steel tube Li -centrally intermediate the ends of -which is seeureda- 'stout metal casting 4 presenting an-upri'ght c'ollarS. Fre'ely which is journalled a single front wheel 8. The 1 upper portion of this stub is threaded and engaged by a nut- 6a to hold the box-7 secured to the collar 5. Two laterally spaced rear wheel 9 are located on an axle 10 at a rearchain wheel 15- securedtoor formed integrally withthe front driving wheel can,
- tion,: the remaining being obtained by placing tion comprise an upright column 17 at its top-end'is-provided-witha transverse, rubber-or plastic-faced manual grip 18. a portion 18a of this-manual relative to :the remainder, whereby rotary movement-of within: the grip and adapted to control electrical energy to the driving motor. andialso to. enable the upright column ably connected with the motor and front wheel housing, the lower end of the steering column and the interior of 19a, 19b. The stub'and the lower end front drivingwheel 8 of the chair 2 itself. Ball races 16 may; if desired, be interposed between the metal collar 5 and the stub 6 projecting from the upper face-ofthe housing 7, and it will be appreciated that by coupling to the-stub, a suitable means for effecting rotation thereof relative to said collar, the motor housing and'hence'the ifdesired, be rotated through a full 360. Preferably, h owever, mutually co-operating stop-means (not shown) are incorporated on the stub 6 and the metal collar 5 to prevent arotationgreater with the chair moving in a forward direcof a complete turning circle the chair in'reverse. "Inthis conneetion-it-willbe noted-that -the box 7- is suspended 'in-the collar '5 at a forward region-of said-box, so that the longer rearward portion is housed and freely rotatable between the sideimembers of the a chair framework.
'The steering means in this embodiment of the inven- (Figs. 1 and 3) which than about As will be described 'later, gripmay be made rotatable said-portion 18a may operate an electric switch'25 housed the sup-ply of For this reason, 17 to be detachthe stub 6 at-the top of the housingrnay be provided with mutually co-operating electrical plug and socket means of the steering column are likewise provided with mutually f o-operating stout pinZll and-a keyway 21 adapted for interengageement to transmit steering movementsfrorn the column 1 to the stub.
One or morestorage batteries diagrammatically-indicated at 22 for supplying electrical energy to the driving motor-11, areicarried on a tray 23 extending transversely across; the baseot-the chair framework, for example-Ibe- I tween the two rear wheels 9, only a single lead into the motor and front wheel housing 7 being necessary, since the return path to the battery may conveniently be completed through the metal framework of the chairZ. In
order to provide a relatively slow and also for a faster forward speed, it has been found convenient to use a change-field motor having two windings, and switch means for placing these windings either in series or parallel.
The switch means also provides for reversing the con-' SS provided with two make contacts 31. The manual grip 18 at the upper end of the steering column, at an inner region thereof, fixedly houses a three-pole, four position manually operated rotary switch 25, the control spindle 32 of which is secured to the manually rotatable outer portion 18a of the manual grip 18. In this rotary switch 25 (see Fig. the wiper 33, 33' and 33 of each section is connected, via an isolating switch SW, to the chair frame, which in turn is connected to the negative pole of the battery 22, and one position 34, 34' and 34" in each section of the switch 25 is left disconnected to provide for a stop position. Preferably this stop position is provided at the second position of each section of the switch 25, considering rotation of the control spindle and hence of the wiper in a clockwise direction. The remaining clockwise positions of two sections of switch 25 are commoned together and connected to one end of the operating coil of the relay RF, which also has a make 7 contact 35 adapted on operation of said relay, to extend earth to the operating coil of relay SS, the other end of the operating coil of relay SS being connected to battery positive. The make contacts 31 of relay SS are paralleled and inserted in the positive battery lead through the motor armature 26 so that relay SS thus operates as a start relay. The motor armature 26 is so connected to the contacts 36 of the relay RF, that, as shown, this relay can operate to reverse the current through the armature 26, whereby the direction of rotation of the motor 11 is reversed. It will be observed the earth is also extended to the operating coil of relay SS when the switch 25 is in its fully anti-clockwise position, but that in this case relay RF does not operate. Thus, in the fully anti-clockwise position of switch 25, the motor 11 drives the chair 2 in reverse, but when switch 25 is in either of its two clockwise positions, relay RF operates to reverse the current through the armature and hence the drive is forward.
I field coils 27 is connected across the two movable contacts of this relay, the other field coil 28 being connected across two of the fixed contacts thereof, one of the latter being connected to the chair frame. A cross-connection including a resistor R is then made between two diagonally opposite fixed contacts of the change-over contacts on this relay HF (but not so as to include that fixed contact which is connected to the chair frame) whereby on operation of relay HF the series connection of the field coils 27 and 28 necessary for a smooth start and slow speed is changed into a parallel connection enabling the motor 11 to develop its full power and to drive at a higher speed.
In the third section of the manually operated rotary switch in the steering column grip, therefore, the fourth position is connected to this last-mentioned relay HF and the first position, thus requiring the wipers to pass through the stop position first, is connected to the reverse relay RF as mentioned above. In order to prevent abrupt rotation of the manually operated switch 25 from a forward speed straight through the stop position and into reverse, the steering column grip 18 includes pin and gate means (not shown) requiring axial displacement of the rotary portion 18a of the grip on changing from forward to reverse movement of the chair.
The double pole change over relay RF, which changes armature polarity for forward and reverse, normally (in the non-energized position) has the motor connected so as to propel the chair backwards; also it will be noted that the starting relay SS (in the non-energized position) has its upper fixed contact connected to battery negative. In this state, if the chair is pushed or otherwise propelled forward other than by the motor, there will be an electrical generating action within the motor, the power from which is dissipated through the resistor R. This selfgenerating action within the motor (which behaves and acts like a dynamo in these circumstances) causes a considerable retarding force within the motor and acts as a brake to the chair. This action takes place regardless of whether the battery is connected or not, and the eifect is that the chair will be kept at a safe slow walking speed down steep ramps, regardless of the weight of the person. The state of charge of the batteries in no way affects the action just described.
It will be appreciated that the features proposed by the invention provide a high degree of manoeuvrability and either forward or rearward motion in a chair of com pact construction and of dimensions sufficient only to seat a user comfortably in an upright position. Since the steering and driving components of the chair, once the detachable steering column is removed, are contained wholly in the lower portion of said chair, it will be appreciated that it is possible to make the upper portion thereof detachable from the lower portion, as indicated at 29, whereby the two portions may readily be housed, for example, in the luggage compartment of an automobile if desired. Alternatively, the upper portion may be placed on the vehicle seat, where it may be sat in and hence, in effect, occupy no room at all. Hingedly attached to the chair frame by brackets 38 and 39 is a foot board 40 for the comfort and convenience of the occupant.
I claim? 1. An electrically driven invalid chair comprising a chair frame including a pair of vertical, parallel spaced members at the front of said frame, a seat and means for horizontally supporting said seat with respect to said members, a pair of spaced, rear wheels rotatably secured to the back of and within said chair frame and supporting said back of said frame thereon, a horizontal bar extending between and secured to said vertical members below the level of said seat, a fixed collar centrally disposed on said bar, an electrical motor and housing therefor located below said horizontal bar and said seat and having a major portion of said housing disposed within said chair frame, a front wheel mounted on the undersurface of said housing and means driven by said motor within said housing for imparting a driving force to said front wheel, a fixed stub on the upper surface of said housing, said stub having an electrical connector therein, said stub rotatably engaged within said collar, an upright steering column having its lower end rotatably and removably secured within said collar and a handle on the other end of said column, said steering column located adjacent the front edge of said seat, said lower end of said steering column having an electrical connector in removable engagement with said corresponding connector on said stub, and an electrical switch on said handle for controlling the operation of said electrical motor in said housing and imparting movement to said chair.
2. The electrically driven invalid chair defined in claim 1 wherein the electrical connectors on said steering column and said stub are male and female plugs.
3. The electrically driven invalid chair defined in claim 1 wherein said means for horizontally supporting said seat with respect to said vertical, parallel spaced members includes a pair of spaced tubular members which removably engage said vertical members and support said seat in cantilever fashion.
4. An electrically driven invalid chair comprising a chair frame including a pair of vertical, parallel spaced members at the front of said frame, a seat and means for horizontally supporting said seat with respect to said members, a pair of spaced rear wheels rotatably secured to the back of and within said chair frame, said rear wheels supporting the back of said chair frame, a horizontal bar extending between and secured to said vertical members, a fixed collar centrally located on said bar below the level of said seat, an electrical motor and housing therefor located below said horizontal bar and said seat and having a major portion of said housing disposed within said chair frame, said housing rotatably mounted on said collar, a front wheel mounted on the undersurface of said housing and first means driven by said motor within said housing for imparting a driving force to said front wheel, second means on the upper surface of said housing including an electrical connector,
a rotatable upright steering column inserted within said collar and a handle on the upper end of said column, said steering column located adjacent the front edge of said seat, the lower end of said steering column having an electrical connector in removable electrical contact with said electrical connector on said second means, and an electrical switch on said handle for controlling the operation of said electrical motor in said housing and imparting movement to said chair.
References Cited in the file of this patent UNITED STATES PATENTS 693,102 Bowker Feb. 11, 1902 1,781,792 Rodman Nov. 18, 1930 2,468,801 Beall May 3, 1949 2,482,472 Fried Sept. 20, 1949 2,513,718 Gfrorer July 4, 1950 2,586,273 Steven Feb. 19, 1952 2,635,703 Goeller Apr. 21, 1953 2,642,121 Frick June 16, 1953 2,814,505 Kelly Nov. 26, 1957