US3100860A

US3100860A - Motor drive control for wheelchair

Info

Publication number: US3100860A
Application number: US766294A
Authority: US
Inventors: Rosenthal Harry
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-10-09
Filing date: 1958-10-09
Publication date: 1963-08-13
Anticipated expiration: 1980-08-13

Description

' H. ROSENTHAL MOTOR DRIVE CONTROL FOR WHEELCHAIR Aug. 13, 1963 2 Sheets-Sheet 1 Filed Oct. 9, 1958 Aug. 13, 1963 H. ROSENTHAL I 3,100,860- I MOTOR DRIVE CONTROL FOR WHEELCHAIR Filed Oct. 9, 195a 2 sheets-sheet 2 T0 BATTERY Unite Stats l at 3,100,860 I MOTOR DRIVE coNTRoL non ELcrrAm 7 Harry Rosenthal, 6540 N. Campbell Ave, Chicago, lil- Filed Oct. 9, 1958, Ser. No. 766,294 4 Claims. (Cl. 318-55) for electric driving apparatus used with such chairs.

Electrically driven wheelchairs for use by physically handicapped persons have been known generally in the prior art and some have been provided with control means for driving the chair at different speeds in both forward and reverse direction and for turning of the chair. However, the control apparatus for such chairs has generally been rather complex and involve the manipulation of a number of separate control buttons, dials or the like in order to turn or change the speed and direction of movement of the chair. Since wheelchairs are often used by persons whose manual dexterity and strength is serious- 1y limited, there is a definite need to provide control apparatus for such chairs which are operable through a single easily manipulated control member and which will, at the same time, be sufliciently versatile and flexible to provide a high degree of maneuverability.

It is generally desirable that a motor driven wheelchair be provided with two ranges of operating speeds; a higher speed for use outdoors and a lower speed for use indoors. While it is desirable that the chair be operable at different speeds within each range, it is preferable that control means be provided such that a change from one range to the other is not made inadvertently. At the same time, the provision for different speed ranges should be made without unduly complicating the control means for the chair.

Accordingly, it is an object of the present invention to provide control apparatus for a motorized wheelchair which controls are particularly easy to operate and adapted for use by partially disabled persons.

Another object of the invention is to provide a motorized' wheelchair easily operable at different speeds and in different directions and within different speed ranges.

A further object of the invention is to provide an'electrically driven wheelchair incorporating a single speed and direction control member operative on the so-called joystick principle and effective to control both the speed and the turning of the chair.

A feature of the present invention is the combination I of a pivotally mounted control element with a series of leaf-type switches to permit the speed and direction of rotation of the wheels of an electrically driven chair to be controlled separately by the progressive incorporation of resistance elements to control the speed and direction of rotation of electric motors.

A further feature of the invention is the provision of a pair of leaf-type switches connected to the field coil of a motor driving a chair wheel with one of the switches in its normal or unactuatediposition providing a current path which cooperates with a current path through the other switch when the latter is in its actuated position to direct current through the iield coil in a predetermined direction. With the first of the switches actuated and the second in its normal position, the switches cooperate to a form a current path through the field coil in the opposite direction to produce reverse rotation of the wheel.

Another feature of the invention is the provision of a double-throw switch for incorporating or eliminating resistance elements into an electric driving system'for a motorized wheelchair in order to provide for different speed ranges of operation for such chair.

3 1%,856 Patented Aug, 13, 1963 In the accompanying drawings:

FIG. 1 is a perspective view illustrating the general organization of an electrically driven wheelchair utilizing the control means of the present invention;

FIG. 2'is a view in section taken through the top of the control box used with the chair shown in FIG. 1;

FIG. 3 is a view in section taken on the line 33 of FIG. 2;

FIG. 4 is a view in section taken on the line 44 of FIG. 2;

FIG. 5 is a schematic diagram of the wiring circuit used for the control means of the present invention; and

FIG. 6 is a schematic diagram of a portion of the wiring V circuit illustrating an alternative embodiment of the invention.

A motorized chair in accordance with the present invention includes a pair of independently operated electric motors powered by a storage battery and each arnanged to drive a wheel of the chair. Control of the drive is accomplished through a pivotally mounted joy-stick member which has four leaf-type switches positioned around its axis and spaced apart. Operation of the joy-stick may progressively close the contacts of the leaf-type switches one or two at a time and in so doing connect the driving motors to the battery and incorporate resistances of different values into the circuit in order to control the current through the field coils of the respective electric motors and thus control their speeds of rotation. A separate double pole, double throw switch may be provided to incorporate separate additional resistances into the drive circuits so that field coil current of a lower range is available thus pnoviding for drive at various lower speeds. When the range switch is set to its high speed position, the aforesaid independent resistances are cut out'of the circuit permitting field coil current in a higher range to flow for higher speeds of operation. A pair of the aforesaid leaf switches are connected in such a waythat when they are closed they provide a reverse current in the field coils of the respective motors and permit backward movement of the chair. Because the joy-stick control element is operative in a 360 range it is possible to simultaneously forward drive one wheel while reverse driving the other thus permitting sharp turning of the chair. The control member thus consists of a single element which is easily controlled even by an incapacitated person while pemnitting a relatively wide range of speeds to be' employed and making the chair highly maneuverable.

Referring now to the drawings, FIG. 1 is a perspective view of an invalids wheelchair incorporating the present invention. The chair may be of standard construction including a frame 10, a seat 12, baclr l4 and footrests 15. The frame Ill is provided with main driving wheels 16 and 17 being disposed on opposite sides of the frame, both wheels being rotatably mounted on axles such as 18. Smaller front wheels 19 are pivotally secured to the frame to provide a stable balanced structure. Vertical frame members 21 and 22 extend upwardly from the lower frame members 23 and 24 respectively and these vertical frame members serve to support the seat 12 and back 14-. Suitable handle grips 26 are provided so that the wheelchair may be conveniently moved by an attendant. Arm rests 217 are also provided for the chair and supported by other members of the frame.

The apparatus for propelling the wheelchair include reversible electric motors 2'8 and 29 which are mounted on their respective support brackets 31 and 32 disposed on the frame members 23 and 24. The motors 28 and 229 include suitable gear reduction mechanisms which operate the driving drums 33 which are adapted to be moved into or out of engagementwith the wheels '16 and 17 through the operation of

levers

34 and 36.

A standard 12 volt battery 37 is suitably supported beneath the seat of the chair and supplies current to the motors Z8 and Z9 andto the control box 39 which is connected to the motor through the cables 41 and 42.

The control box 3 9', as shown in FIGS. 2 and 3, contains a pair of connection boxes 43 and44 for the cables 41 and 42 respectively, and the

rheostats

46 and 47. A icy-stick type control member '48 is pivotally mounted in the top of the control box as more clearly shown in FIG.

4. Leaf switches 51, 5'2, 53 and 54 are mounted in the I bottom of the control box 39 adjacent one end of the joy-stick'control member. As best shown in FIG. 2-, the

leaf-type switches are arranged around the bottom of at its lower end. A ball 61 is disposed on the shaft 57 and is mounted between the

socket washers

62 and 63 so that a ball and socket connection is formed. This per- 4 contact with leaf 53d with flexible leaf 54c being carried into contact with flexible leaf 54d. It will be evident that in this connection the arms 53b and 5412 are connected to an intermediate point on the

rheostats

46 and 47 so that the current through

field coils

28a and 29a is increased and the speed of rotation of motors 28 and 29' and of the wheels 16 and 17 increases correspondingly. Still further movement, of the knob 58 to the forward position carries

leaves

53d and 54d into engagement with leaves 53c and S4e thus effectively shortingout the

rheostats

46 and 47 andfurther increasing the speed of rotation of the wheels.

When the operator desires to move the chair backwards he pulls the knob 53 toward him thus bringing the contact plate 59 against extension arms 515a and 52x to move

leaves

51b and 52b into contact with leaves 510 and 520 respectively. In this position the

switches

53 and 54 have their respective a and bleaves connected to one another thus providing current paths through those switches. It will be evident from FIG. 5 that in this position connection is made to battery 37 so that l the direction of current flow through the field coils 28a mits the member 43 to be pivoted forward, backward, to

either side or to any intermediate position such as forward and to the left or backward and to the right.

Each of the leaf switches numbered 51 through 54 (FIG. 5) includes flexibile contact arms which are designated by

reference characters

51a, 51b,'51c and 51d,

for example, on the reverse switch 51 and designated by

reference characters

53a, 53b, 53c, 53d and 53e on the forward switch 53. Thus,

forward switches

53 and 54 are provided with live leaves whereas the

reverse switches

51 and 52 have but, four leaves. The leaf 51b has an extension portion designated 51x against which the contact plate 5 9 is adapted to bear on backward movement of the knob 58, while the leaf 53b has a corresponding 7 extension 53x. The

other switches

52 and 54 have corresponding leaves and extending portions illustrated in the schematic diagram of FIG. 5.

As indicated in FIG. 5,

switches

51 and 54 control the motor 28 which drives the right wheel 16 of the chair while the

switches

52 and 53 control the motor 29 driving the left wheel 17.

Switches

51 and 54 are connected to the rheostat 47 while the

switches

52 and 53 are connected to rheostat 46. The double pole, double throw switch 56 provides for connection ofrthe battery 37 to the

field coils

28a and 29a of the respective motors.

In operation of the chair the arm 77 of switch 56 is moved to'connect the

centralcontacts

78 and 79 either to 'low speed contacts '81 and 82' or to the high speed contacts 8 3 and 84. Connection. to the low speed contacts connects the

variable resistors

66 and 67 into circuit so that a lower level of current is supplied to the

field v coils

28a and 29a than is supplied when the high speed contacts 86 and 84 are connected and the resistors are shorted out. a

Assume that the switch 56 is closed in the low speed position and thatthe operator wishes to move the chair straight forward at the lowest available speed. This is .accomplished by grasping the knob 58 and pushing it forward. This causes the ball 56 to pivot within the socket washers and brings the contact plate 59 against the exten- 1 sions '5-3x and 54x thus moving flexible leaves 53b and 54b out of contact with leaves 53a and 54a respectively and into contact with leaves 530 and 54s respectively.

At the same time, switches 51 and 5 2 are in their normal positions so that there are current carrying paths through

closed contacts

51a, 51b and 52a, 52b. This establishes a connection between the battery 37 and the field colil 28a through the entire resistance of rheostat 47 and likewise connects the battery to field coil 29a through the entire resistance of the rheostat 46 thus driving both wheels forward at the same speed. As the knob 58 is moved further forward, flexible leaf 53c is pushed into and 29a will be the reverse of the direction in which the current flows when the

switches

53 and 54 were actuated. The connections made include the

rheostats

46 and 47 so that a controlled amount of resistance is introduced into the circuit and the speed of rotation of the wheels 16 and 17 thus regulated. If it is desired to drive the chair backward at a greater speed the knob 58 is moved further backward so that flexible leaf 51(: contacts leaf 51d and leaf 52c contacts leaf 52d. This provides connection to intermediate points on the

rheo stats

46 and 47 reducing their effective resistance and permitting higher speed of rotation of the wheels.

Turning the chair is accomplished by moving the knob 58 in the direction in which the turn is to be made. For example, if a right turn is to be madeimovement of the knob 58 to the right will cause the joy-stick mem- 7 since this permits positioning of the contact member 59 so that it will cause rotation of the wheels at diiferent rates of speed. For a less sharp tur-n knob 58 maybe moved forward and to the right so that contact member 59 closes switch 53 only with switch 51 remaining open and right wheel 16 remaining stationary. Also, switch 53 may be closed further than switch 54 for an even more gradual turn..

When it is desired to operate the chair at higher speeds, the arm 57 of the double throw, double pole switch 56 is moved against

connections

83 and 84 thus eifectively bypassing the

resistors

66 and 67 and reducing the total amount of resistance in the circuit. In this way, a higher speed range is provided with adjustment within this range being made by the position to which the knob 58 is moved. It is to be pointed out that a single throw switch may be used instead of the [double throw switch to provide operation through a single range of speeds if desired. 7

The action of the joy-stick member '48 maybe made quite tree so that relatively little effort on the part of the operator is required to hold the switches closed.

Although the particular arrangement illustrated shows a control system and in which three forward speeds and two reverse speeds are shown for each of the high and low speed ranges it will be understood that a greater or lesser number of different speeds may be provided simply by changing the number of contacts on the leaf springs.

FIG. 6 illustrates an alternate speed control system providing two forward speeds and two reverse speeds. The

switches

152 and 153 correspond rfunctionally to chair.

switches 52 and 53 respectively in FIG. and areconnected in circuit in the same way as indicated by the reference characters and legends at the ends of the brokenoffleads. Switches 152 and 153' are associated with a potentiometer 146 which provides apredetenmined speedcontrolling resistance. For low speed forward rotation of the left wheel of the chair, extension 153x is moved by the joy-stick and pushes leaf 153b into contact with leaf 153a so that the entire resistance of potentiometer 146 is in circuit; To increase forward speed, the operator manipulates the joy-stick to :bring leaf 1530 against leaf 153d so that only a portion of the total potentiometer resistance (deter-mined 'by the position of arm 146a) is connected. The position of arm 146a may be controlled by means on the outside of control box 39 so that the maximum speed maybe varied by the user to suit different conditions. Reverse driving speed is controlled in the same way through'switch 152. A corresponding set of switches and potentiometer speed control is provided for the right wheel.

The present invention provides, therefore, a simple and easily operated control for a motor driven wheel- By providing the combination of the joy-stick control member and the leaf switches great flexibility of speed control is provided. Furthermore, since different wheels can be rotated in different directions and diiferent speeds depending on the positioning of the control knob, a chair equipped with such control means is highly maneuverable and may be operated easily by a partially incapacitated person.

I claim:

:1. Electrical control means for a vehicle having on each of two sides thereof a supporting wheel and a reversible electric motor for driving the same, with the wheel and motor on one side operating independently of the wheel and motor on the other side, said control means including in combination, first and second circuits individually connected to the motors for energizing the same, a pair of leaf switches electrically connected in each circuit, the first switch of each pair having a plurality of flexible leaves including anintermediate leaf with one leaf on one side thereof and atleast two leaves on the other side thereof, with the leaves being engaged in sequence by movement of said intermediate leaf thereof to cause current fiow in the associated circuit in one direction to provide rotation of the corresponding motor and wheel in the forward direction, the second switch of each pair also having a plurality of flexible leaves with an intermediate lea-f being movable to cause current fiow in the associated circuit in the opposite direction to provide rotation of the corresponding motor and wheel in the reverse direction, said first switches of said pairs being oppositely disposed from said second switches thereof, and said switches of one pair being positioned at right angles with respect to said switches of the other pair, a joy-stick control member pivotally mounted intermediate said first and second switches of both pairs for selectively moving said intermediate leaves thereof to operate said switches, whereby only'one "switch of each pair may be operated at a given time, and resistor means connected to said leaves on said other side of each of said first switches to introduce resistance into said circuit in one position of said first switches to control the current flow in said circuits and thereby control the forward speed of the motors. i

2. Electrical control means for a vehicle having on each of two sides thereof a supporting wheel and a reversible electric motor for driving-the same, with the wheel and motor on one side operating independently of the wheel and motor on the other side, said control means including in combination, first and second circuits individually connected to the motors for energizing the same, a pair of leaf switches electrically connected in each'circuiL'the first switch of each pair having a pinrality of flexible leaves including an intermediate leaf with one leaf on one side thereof and at least two leaves on the other side thereof, with the leaves being engaged in sequence by movement of said intermediate leaf thereof to positions to cause current flow in the associated circuit in one direction to cause rotation of the corresponding motor and wheel in the forward direction, the second switch of each pair also having a plurality of flexible leaves and being actuated by movement of an inter-mediate leaf thereof to cause current flow in the associated circuit in the opposite direction to cause rotation of the corresponding motor and wheel in the reverse direction, said first switch of each pair being oppositely disposed from said second switch thereof, and said switches of said first pair being positioned at right angles with respect to said switches of said second pair, a joy-stick control member pivotally mounted intermediate said first and second switches of both pairs for selectively moving said intermediate leaves thereof to opcrate said switches, whereby only one switch of each pair may be operated at a given time, resistor means connected to said leaves on said other side of said intermediate leaf of each of said first switches to introduce varying amounts of resistance into said circuit as said leaves on said other side of said first switches are engaged in sequence by progressive movement of said controlmember to control the current flow in said circuit and thereby control the forward speed of the motor, and resistance means connected in series with each pair of said leaf switches by means of a leaf of each of said first and second switches on the other side of said intermediate leaf thereof for providing resistance in said circuit independently of the position of said joystick control member.

3. Electrical control means for a vehicle having on each of two sides thereof a supporting wheel and a reversible electric motor for driving the same, with the wheel and motor on one side operating independently of the wheel and motor on theother side, said control means including in combination, first and second circuits individually connected to the motors for energizing the same, a control box adapted to be mounted on the vehicle, a joy-stick control device pivotally mounted on said control box with a knob extending above the control box and an actuating member within said box, a first pair of leaf switches connected in said first circuit and disposed in said box on opposite sides of said actuating member, and a second pair of leaf switches connected in said second circuit and disposed in said box on opposite sides of said actuating member, said switches of said second pair being positioned at right angles to said switches of said first pair, and each of said switches being angularly spaced about with respect to the adjacent switch about said actuating member and at substantially forty-five degrees to the direction of movement of the vehicle, the first switch of each pair having a plurality of vfiexible leaves and being engaged in sequence to cause current flow in the associated circuit in one direction to cause rotation of the corresponding motor and wheel in the forward direction, the second switch of each pair having a plurality of flexible leaves and being operable to cause current flow in the associated circuit in the opposite direction to cause rotation of the corresponding motor and wheel in the reverse direction, said actuating member selectively engaging said switches to operate the same, each of said circuits and said pair of switches connected thereto being arranged to open the circuit and de-energize the associated motor in the event that both switches of said pair are simultaneously operated.

4. Electrical control means for a vehicle having on each of two sides thereof a supporting wheel and a reversible electric motor for driving the same, with the wheel and motor on one side operating independently of the wheel and motor on the other side, said control means including in combination, first and second circuits individually connected to the motors for energizing the same, a control box adapted to be mounted on the vehicle, a joy-stick control device pivotally mounted on said control box with a knob extending above the control box and a round actuating member within said box, a first pair of leaf switches connected in said firstcircuit and disposed in said box on opposite sides of said actuating member, a second pair of leaf switches connected in said second circuit and disposed in said 'box on opposite sides of said actuating member, said switches of said second pair being positioned at right angles to said switches of said first pair and eachof said switches being angularly spaced about 90 with respect to the adjacent switch about said actuating member, the first switch of each pair having a plurality of flexible leaves including an intermediate leaf with one leaf on one side thereof and at least two leaves on the other side thereof, with the leaves on said other side being engaged in se quence by movement of said intermediate leaf thereof to positions to cause current fiow in the associatedcircuit in one direction to cause rotation of the corresponding motor and wheel in the forward direction, the second switch of each pair having a plurality of flexible leaves and being actuated by movement of an intermediate leaf thereof to positions to cause current flow in the associated circuit to cause rotation of the corresponding motor and wheel in the reverse direction, said actuating member selectively moving said intermediate leaves of said switches: to operate the same, each of said circuits and said pair of switches connected thereto operating to open the circuit and de-energize the associated 'anotor when both switches of said pair are simultaneously operated, and resistor means connected to said leaves on said other side of said first switches to introduce resistance into said circuit in one position of said first switches to control the current flow in said circuits and thereby control the forward speed of the motors.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. ELECTRICAL CONTROL MEANS FOR A VEHICLE HAVING ON EACH OF TWO SIDES THEREOF A SUPPORTING WHEEL AND A REVERSIBLE ELECTRIC MOTOR FOR DRIVING THE SAME, WITH THE WHEEL AND MOTOR ON ONE SIDE OPERATING INDEPENDENTLY OF THE WHEEL AND MOTOR ON THE OTHER SIDE, SAID CONTROL MEANS INCLUDING IN COMBINATION, FIRST AND SECOND CIRCUITS INDIVIDUALLY CONNECTED TO THE MOTORS FOR ENERGIZING THE SAME, A PAIR OF LEAF SWITCHES ELECTRICALLY CONNECTED IN EACH CIRCUIT, THE FIRST SWITCH OF EACH PAIR HAVING A PLURALITY OF FLEXIBLE LEAVES INCLUDING AN INTERMEDIATE LEAF WITH ONE LEAF ON ONE SIDE THEREOF AND AT LEAST TWO LEAVES ON THE OTHER SIDE THEREOF, WITH THE LEAVES BEING ENGAGED IN SEQUENCE BY MOVEMENT OF SAID INTERMEDIATE LEAF THEREOF TO CAUSE CURRENT FLOW IN THE ASSOCIATED CIRCUIT IN ONE DIRECTION TO PROVIDE ROTATION OF THE CORRESPONDING MOTOR AND WHEEL IN THE FORWARD DIRECTION, THE SECOND SWITCH OF EACH PAIR ALSO HAVING A PLURALITY OF FLEXIBLE LEAVES WITH AN INTERMEDIATE LEAF BEING MOVABLE TO CAUSE CURRENT FLOW IN THE ASSOCIATED CIRCUIT IN THE OPPOSITE DIRECTION TO PROVIDE ROTATION OF THE CORRESPONDING MOTOR AND WHEEL IN THE REVERSE DIRECTION, SAID FIRST SWITCHES OF SAID PAIRS BEING OPPOSITELY DISPOSED FROM SAID SECOND SWITCHES THEREOF, AND SAID SWITCHES OF ONE PAIR BEING POSITIONED AT RIGHT ANGLES WITH RESPECT TO SAID SWITCHES OF THE OTHER PAIR, A JOY-STICK CONTROL MEMBER PIVOTALLY MOUNTED INTERMEDIATE SAID FIRST AND SECOND SWITCHES OF BOTH PAIRS FOR SELECTIVELY MOVING SAID INTERMEDIATE LEAVES THEREOF TO OPERATE SAID SWITCHES, WHEREBY ONLY ONE SWITCH OF EACH PAIR MAY BE OPERATED AT A GIVEN TIME, AND RESISTOR MEANS CONNECTED TO SAID LEAVES ON SAID OTHER SIDE OF EACH OF SAID FIRST SWITCHES TO INTRODUCE RESISTANCE INTO SAID CIRCUIT IN ONE POSITION OF SAID FIRST SWITCHES TO CONTROL THE CURRENT FLOW IN SAID CIRCUITS AND THEREBY CONTROL THE FORWARD SPEED OF THE MOTORS.