Rotating wheelchair arm

Abstract

A movable wheelchair arm rest which is pivotally mounted on a pair of rotating links to move arcuately between forward and rear positions, the rear position allowing access to the side of the chair. The arm includes interconnecting means which mate with interconnecting means on the wheelchair frame to securely and rigidly anchor the arm in both the forward and rear positions.

Description

BACKGROUND OF THE INVENTION

This invention relates to movable armrests for wheelchairs and more particularly to a wheelchair arm which may be conveniently moved between two alternate positions, the arm being rigidly anchored in each position to provide safety and comfort for the wheelchair occupant. Movement of the arm is desirable to permit convenient access to and from the side of the wheelchair for the occupant.

Although the need for a movable or removable armrest for wheelchairs has long been recognized, particularly to enable patients who have lost the use of their legs to slide sideways onto or off of the chair onto a bed, chair, etc, prior art devices have tended to compromise either the degree of possible movement of the movable arm or, in the alternative, the sturdiness of the arm's attachment to the chair and have therefore solved the problem only at the expense of either safety and comfort or convenience. The most apparent solution to the problem is a totally removable armrest, which, for example, commonly includes members which telescope into supporting members attached to the wheelchair frame. However, it is readily recognized by those skilled in this art that this solution permits convenient access to the chair but results in the likelihood of a loss of the armrest or the difficulty of locating a convenient place to store the armrest when it is removed. In addition, in order that the telescoping fit be relatively secure, the interconnection must be a close fit and many handicapped persons are unable, by themselves, to reengage the armrest once it has been removed from the chair.

Some prior art devices have used rotating links for pivoting the arm between a forward and rear position. Such armrests however have utilized the pivoting connection of the links as the only source of lateral support for the armrest, resulting an arm which in either the forward or rear position tends to wobble toward and away from the center of the chair, making the armrest both uncomfortable and unsafe.

SUMMARY OF THE INVENTION

It is therefore the purpose of this invention to provide a wheelchair armrest which is conveniently movable by a disabled occupant from a normal forward position to a retracted alternate position, which armrest is rigidly secured to the wheelchair frame in each of these positions to provide both safety and comfort.

In accordance with this purpose, the armrest is pivotally mounted at the end of a pair of rotating connecting links, the alternate end of each of these links being, in turn, pivotally connected to the wheelchair frame. This pivotal connection permits the wheelchair arm to move arcuately between two positions removed from one another by approximately twice the length of the pivoting links. Such an arrangement permits a substantial forward and rearward movement of the wheelchair arm to provide convenient access from the side of the wheelchair when the arm has been retracted. In addition, sockets are provided on the wheelchair frame which engage with members which extend from the movable arm so as to securely support the arm against the lateral movement in both the forward and rearward position. These sockets are constructed to permit the arm to arcuately enter the sockets while still providing the necessary support. The result is an extremely rigid arm construction when the arm is in either the forward or rear position, thus substantially enhancing the comfort and safety of the wheelchair occupant and permitting the occupant to use the arm, even in its rear position, as a source of support as he is moving into and out of the chair.

These and other advantages of the present invention are better understood through the following detailed description which makes reference to the drawings, in which:

FIG. 1 is a perspective view of a wheelchair embodying the rotating arm of the present invention;

FIG. 2 is a side elevation view of the wheelchair of FIG. 1;

FIG. 3 is a detailed perspective view of the mounting members used for attaching the rotating wheelchair arm shown in FIG. 1, these members being removed from the wheelchair to better detail the construction thereof;

FIG. 4 is a sectional view taken along lines 4--4 of FIG. 3; and

FIG. 5 is a view, partially in section, taken along lines 5--5 of FIG. 3 showing a portion of the underside of the interconnecting link attached to the rotating arm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring initially to FIGS. 1 and 2, the typical wheelchair construction is shown, along with the rotating armrest of the present invention. The typical wheelchair construction includes a pair of driving wheels 11 and 13 which are pivotally mounted at their hub to a pair of rear vertical members 15 and 17, respectively. In addition, a pair of caster wheels 19 and 21 are mounted at the junction of a pair of forward vertical members 23, 25 and a pair of lower horizontal structural members 27, 29, respectively. Upper horizontal structural members 31, 33 on either side of the wheelchair frame complete the basic frame structure. The structural members 15, 23, 27 and 31 and the corresponding structural members on the alternate side of the wheelchair are rigidly attached to one another to form a basic structural side member of the chair. These members are, in turn, connected through a seat structure 35 to one another to form a rigid rolling platform or frame to which the backrest 37 and the rotating arms of the present invention are attached. It should be noted that the backrest 37 is narrower than the total distance between the wheels 11 and 13 by an amount sufficient to permit movement of a pair of armrests 39 and 41 between the backrest 37 and the wheels 11 and 13, respectively.

Since the manner of attaching each of the rotating armrests 39 and 41 to the wheelchair is identical, only the connecting mechanism for the armrest 39 will be described.

The details of the preferred embodiment of the rotating wheelchair arm of the present invention may now be described, particularly in reference to FIGS. 3-5. The wheelchair arm 39 itself is constructed in almost the identical manner in which a removable wheelchair arm is constructed, and thus includes forward and rear vertical structural members 43 and 45, an upper horizontal structural member 47 on which is rigidly attached a pad member 49, and a lower horizontal structure member 51. It will be recognized that the structural members 43, 45, 47 and 51 are rigidly attached to one another and therefore form the structural framework of the armrest. A wheel guard 52 is conveniently attached to the vertical structural members 43 and 45 to assure that the wheelchair occupant does not slide sideways from the chair to contact the driving wheel 11.

Depending from the lower horizontal member 51 are a pair of square tubular members 53 and 55 which, as will be explained below, form the first half of a pair of interconnecting anchor members which are used to anchor the armrest 39 in either the forward or rear position. Pivotally attached to each of these square tubular members 53 and 55, as by pivotal mounting means 57 and 59, are a pair of rotating links 61 and 63. These links include an opening at the upper end to accommodate the pivotal mounting means 57 and 59 and include a similar aperture in their opposite ends. The lower end of the rotating links 61 and 63 are pivotally attached to the upper horizontal frame member 31 of the wheelchair body in a manner which will be more fully described below.

Rigidly mounted upon the upper horizontal structural member 31 of the wheelchair body are a pair of upstanding interconnecting dog members 65 and 67, each of which has a rectangular cross section throughout its upstanding portion but each of which is conveniently constructed in elevation, as shown in FIG. 3, in the form of a trapezoid. This trapezoidal shape permits the interconnecting square tubular members 53 and 55 to firmly engage the base of interconnecting members 65 and 67 while also permitting movement of the square tubular members 53 and 55 to and from such engagement in an arcuate pattern. The base of the trapezoidal section, that is, the distance between a front face 69 and a rear face 71 on the interlocking member 65 and the corresponding distance on the interlocking member 67 closely approximates the distance between the forward inside surface 73 and the rear inside surface 75 of the interconnecting square tubular member 53 so that, when the interconnecting member 53 is pushed down over the interconnecting member 65, a snug fit exists between these interconnecting members in a longitudinal direction. Even more importantly, the thickness of the interconnecting member 65 closely aproximates the width of the square tubular opening of the interconnecting member 53. Each of these interconnecting members is made sufficiently long to permit substantial interengagement, so that once the arm 39 has been depressed fully to engage the pairs of interlocking members 53, 65 and 55, 67, the wheelchair arm 39 is rigidly and sturdily supported to prevent movement both longitudinally along the wheelchair frame and laterally toward and away from the center of the wheelchair.

At the base of each of the dog members 65 and 67, as best shown in FIG. 3, is an adjoining base element 66 and 68, respectively, which, in addition to facilitating firm mounting of the dog members 65 and 67 to the upper horizontal structural member 31 of the wheelchair body, provide a pair of wedge-shaped grooves 70 and 72 which receive one wall of the square tubular members 53 and 55, respectively, so that the wheelchair armrest 39 may be firmly wedged in either the forward or retracted position.

When the wheelchair arm 39 is raised to disengage the pairs of interconnecting members 53, 65 and 55, 67, it may be moved arcuately as the links 61 and 63 rotate. As previously stated, the trapezoidal shape of members 65 and 67 allows this arcuate movement. This movement retracts the arm 39 to a rear or retracted position as shown in dotted lines in FIG. 2. In this position, the square tubular interconnecting member 53 engages the interconnecting member 67 on the wheelchair frame so that, even in this retracted position, the close fit between these interconnecting members makes the wheelchair arm 37 sufficiently rigid against longitudianl and lateral movement to assure comfort and safety to the wheelchair occupant.

It will be recognized that the interconnecting square tubular members 53 and 55 are rigidly attached to the lower horizontal frame member 51 of the arm 37 and that the upstanding interconnecting members 65 and 67 are rigidly attached to the upper horizontal structural member 31 of the wheelchair frame. While it is possible to construct the wheelchair frame and the wheelchair arm 39 so that the distance between the upstanding interconnecting members 65 and 67 is identical to the distance between the square tubular interconnecting members 53 and 55 so that, in the forward position of the wheelchair arm 39, each of the interconnecting pairs can properly engage, it is extremely difficult to construct the pivotal mounting mechanism for the rotating links 61 and 63 to a sufficient accuracy to assure that the interconnecting members properly engage in both the forward and retracted positions. Therefore, as is shown in FIG. 4, the lower pivotal connection of each of the rotating links 61 and 63 is advantageously constructed in an adjustable fashion so that as the wheelchair is assembled adjustment can be made to assure proper interconnection of the wheelchair arm 37 with the wheelchair frame to assure a sturdy assembly.

The rotating link 61 is pivotally mounted to a bushing 77 as by a screw 79 which fits sufficiently loosely within an aperture 81 within the rotating link 61 to provide rotation. A similar pivotal connection is utilized at the opposite end of the link 61. The screw 79 mates with a threaded bore 83 which is eccentric to the axis of the bushing 77. The bushing 77 fits within a tubular sleeve 85 which is rigidly attached, as by braising or welding, to the upper horizontal structural member 31 of the wheelchair frame. The bushing 77 may advantageously include a threaded extension 87 at one extremity which, through a washer 89 and a nut 91, provides for secure mounting of the bushing 77 within the sleeve 85.

During assembly of the chair, the nut 91 and a corresponding nut used for the mounting of a rotating link 63 is loosened and the interconnecting members 53, 65 and 55, 67 are brought into engagement by rotating the bushing 77 within the sleeve 85, using the eccentricity of the bore 83 to adjust for proper alignment. The nuts 91 may now be tightened and it will be appreciated that the eccentric positioning of the threaded bore 83 accomplishes an adjustment of the lower pivotal connection of the rotating arm 61 and 63 to assure a proper pivoting point for the arcuate movement of the arm 39 to assure proper interconnection of these members. It should also be recognized that the length of each of the rotating pivot arms 61 and 63 may be made sufficiently precise so that once the wheelchair arm 39 properly engages the wheelchair frame in the forward position, proper engagement in the rear position, that is, when the square tubular interconnecting member 53 engages the upstanding interconnecting member 67, is assured.

From the preceding description it will be recognized that the rotating links 61 and 63 are used for convenient movement of the arm between the forward and rearward position but are not dependent upon as the sole means of supporting the arm in either of these positions, that function being primarily achieved by the interconnection of members 53, 65, 55 and 67. The links 61 and 63 also assure that the horizontal members 47 and 51 remain substantially horizontal during movement of the arm. Thus, a significantly more sturdy construction is permitted since the pivotal connections of the links 61 and 63 are necessarily sufficiently loose to permit rotation, but since the members 53, 65, 55 and 67 may be made to engage very securely to anchor the wheelchair arm 39.

Claims

What is claimed is:

1. A wheelchair, comprising:

a wheelchair frame;

an armrest, said armrest including a first interconnecting anchor member, said first interconnecting member being a hollow square tuube depending from and rigidly attached to said armrest;

a pair of links, each pivotally mounted at one end to said frame and at the opposite end to said armrest to provide arcuate movement of said armrest relative said frame between a first and a second position; and

a second interconnecting member, said second interconnecting member comprising an upstanding dog which is rectangular in cross section and rigidly attached to said wheelchair frame, said second interconnecting member having a trapezoidal upper extremity, said first and second interconnecting members positioned to engage with one another when said armrest is in said first position.

2. A wheelchair, comprising:

a wheelchair frame;

an armrest, said armrest including a first interconnecting anchor member;

a pair of links, each pivotally mounted at one end to said frame and at the opposite end to said armrest to provide arcuate movement of said armrest relative said frame between a first and a second position;

a second interconnecting member, attached to said wheelchair frame, said first and second interconnecting members positioned to engage with one another when said armrest is in said first position; and

means for adjusting the center of rotation of each of said pair of links relative said wheelchair frame.

3. A wheelchair as defined in claim 2, wherein said means for adjusting the center of rotation comprises:

a tubular sleeve rigidly connected to said wheelchair frame;

a bushing mounted for rotation within said tubular sleeve, said bushing having an eccentric bore therein; and

means for pivotally mounting one of said pair of links to said eccentric bore.

4. A wheelchair having a retractable wheelchair arm for attachment to the side of the wheelchair, comprising:

a wheelchair frame;

an armrest;

a pair of pivot links;

means for pivotally connecting one end of each of said pair of pivot links to said wheelchair frame;

means for pivotally connecting the other end of each of said pair of pivot links to said armrest; and

means for adjusting the center of rotation of one of said pivotally connecting means with respect to said wheelchair frame to adjust the position of said armrest relative said wheelchair frame.

5. A wheelchair having a retractable wheelchair arm for attachment to the side of a wheelchair as defined in claim 4, wherein said means for adjusting the center of rotation comprises:

a hollow tubular sleeve rigidly mounted to said wheelchair frame;

a bushing mounted for rotation within said sleeve, said bushing including an eccentric bore; and

means for pivotally mounting one of said pair of pivot links to said eccentric bore.

6. A wheelchair having a retractable wheelchair arm for attachment to the side of a wheelchair as defined in claim 4, wherein said means for adjusting the center of rotation of one of said pivotally connecting means with respect to said wheelchair frame adjusts the center of rotation of said pair of pivot links with respect to said wheelchair frame.

7. A retractable wheelchair arm for attachment to the side of a wheelchair, comprising:

a framework including upper and lower horizontal members and forward and rear vertical members, all rigidly attached to one another;

means attached to said lower horizontal member for mounting said framework for arcuate movement relative said wheelchair, said means maintaining said horizontal framework members substantially horizontal during such arcuate movement;

means for rigidly interengaging said framework to said wheelchair in at least one position along the path of said arcuate movement; and

means for adjusting the position of said path of said arcuate movement relative said wheelchair.