US3407896A

US3407896A - Air cushioned wheeled base

Info

Publication number: US3407896A
Application number: US595769A
Authority: US
Inventors: Billin Arthur Gilbert; Remley Walter Lee
Original assignee: Sybron Corp
Current assignee: Sybron Transition Corp
Priority date: 1966-11-21
Filing date: 1966-11-21
Publication date: 1968-10-29
Anticipated expiration: 1985-10-29
Also published as: GB1181167A; SE342743B; DE1566460A1

Description

Oct. 29, 1968 A. G. BILLIN ET AL AIR CUSHIONED WHEELED BASE 2 Sheets-Sheet 1 INVENTORS. ARTHUR GILBERT BILLIN 5O WALTER LEE REMLEY ATTORNEY Oct. 29, 1968 A, G. BILLIN ET AL. 3,407,896

AIR CUSHIONED WHEELED BASE 2 Sheets-Sheet 2 Filed Nov. 21. 1966 FIG?) W .L SH RB m. mm vw mmm R U m R A WALTER LEE REMLEY ATTORN EY United States Patent 3,407,896 AIR CUSHIONED WHEELED BASE Arthur Gilbert Billin,Rochester, and Walter Lee Remley, Penfield, N.Y., assignors to Ritter Pfaudler Corporation, Rochester, N.Y., a corporation of New York Filed Nov. 21, 1966, Ser. No. 595,769 6 Claims. (Cl; 180-119) ABSTRACT OF THE DISCLOSURE A dental chair having a pair of forward located rollers, a rearward located lip and a single rearward located ground effect device, the rollers and the groundeffect device together forming a stable, three point support when air is supplied to the ground effect device for moving the chair along a floor surface, the rearward located lip engaging the floor surface and together with the forward located rollers forming a stable, three point support when air is not supplied to the ground effect device for immobilizing the chair.

This invention relates generally to chairs for supporting dental patients and more specifically, to an air cushion base for such chairs which permit smooth relatively friction free movement of the chair along a floor surface.

A common arrangement in a dentist office has the dental chair positioned adjacent a console. The console is usually stationary and contains such apparatus as a power supply, air compressor, lamps, drills, cuspidor and other instruments necessary for performing dental work. The chair, however, is usually quite mobile and can be raised, lowered, tilted, swiveled and in some designs may be moved on .wheels guided by. floor mounted tracks. This permits the dentist to place the patient in the position most convenient for performing the work required.

The common practice in constructing dental chairs is to have the chair swivel on the pedestal or stand which supports the seat of the chair. Because this pedestal is located directly beneath the seat of the chair swinging, say the patients upper body portion, through an arc will cause his lower body portion to swing in the opposite direction through an equal arc. Therefore, care must be taken when swiveling the chair to prevent bumping the patient against any nearby piece of apparatus or other object. Accordingly, it is an object of our invention to provide a dental chair in which the vertical axis of rotation is located at some point forward of the patient, thereby permitting a relatively large arcuate movement of the patients upper body portion without a corresponding large arcuate movement of the patients lower body portion.

If the chair is movable with respect to the floor sur face, provision must be made to insure that the chair does not move while the dentist is working on the patient, as any unwanted or unexpected movement may result in injury to the patient. Therefore, it is another object of our invention to provide a mobile chair which presents a stable at rest platform for safe performance of work in the oral cavity.

One method for moving the chair along the floor surface is to mount the chair on tracks attached directly to the floor. While this arrangement does provide smooth, relatively friction free motion, certain other drawbacks are created. For example, the tracks present an obstacle to the free passage of rolling equipment close to the chair and the length of the tracks define a limit beyond which the chair cannot move. Therefore, it is yet another object of our invention to provide a dental chair which can move freely over a floor surface unguided by track members.

A more recent inovation for moving dental chairs is to provide the chair with an air cushion device in the chair base which device, when inflated, will permit the chair to 3,407,896 Patented Oct. 29, 1968 float on a thin film of air as shown, for example, in the Deeley and Stram Patent No. 3,254,733. Devices which float a load on an air cushion are commonly known as ground effect devices. A typical ground effect device is illustrated in a patent to H. A. Mackie No. 3,161,247. An air supply is readily available in dentists oflices because low pressure air is used to run high-speed drills and other equipment. However, air cushion devices themselves have several drawbacks when applied to such top-heavy equipment as dental chairs. For example, one large air cushion device for lifting the entire chair may be unstable as a single air cushion device may not be able to adequately compensate for the weight shift as'might be the case when the patient goes from a seated position to a reclining position. If a relatively large patient is seated in a chair, any shift in position may cause the center of gravity to move outside of the area covered by the air cushion device causing the chair to tilt and bind on the floor surface when the device is inflated. In such a situation, the dentist must either return the patient to an upright position when moving him, or the dentist must provide some of the lift himself. Other air cushion devices employing three air pods arranged in a tripod configuration have been used to lift loads. However, here too, the pods may not be able to compensate for weight shift unless separate controls are provided to regulate the flow of air to each pod or the dentist himself balances the load while moving the chair and patient. Therefore, it is a further object of our invention to provide an air cushion base for dental chairs which can compensate for any weight shift to prevent the base from binding on the floor surface.

In both instances, when either one large air cushion device or three smaller air pods are used, the entire combined weight of patient and chair is lifted by the flow of air. The escape of this air from between the ground effect device and the floor surface does not lend itself to hygienic conditions as any dust and bacteria in the dentists office will be blown about. One method of preventing the objectionable escape of air has been to build an air return into the ground effect device which increases the cost of production. Therefore, it is an additional object of this invention to provide an air cushion base for dental chairs which greatly reduces the amount of escaping air without adding to the cost of production.

These and other objects, advantages and characterizing features of our invention will become more apparent upon consideration of the following detailed description thereof, in conjunction with the accompanying drawings depicting the same, in which:

FIGURE 1 is a side elevation of the seat, chair frame, chair support and air cushion base, the solid line indicating the seat and chair frame in a fully reclined position and the dotted line reflecting the seat and chair frame in an upright position.

FIGURE 2 is a view in cross section of the air cushion base showing the air pod in a deflated condition.

FIGURE 3 is a bottom view of the base.

FIGURE 4 is an elevation view in section of the rearward portion of the base showing the air pod in an inflated condition.

FIGURE 5 is a schematic representation of the plan view of the air cushion base with the dotted lines illustrating the manner in which the base can be pivoted about on the roller members.

A dental chair constructed in accordance with our invention can be characterized in one aspect thereof by the provision of a generally oblong-shaped base carrying a pedestal for supporting the chair above a floor surface, a pair of roller members journaled to the forward end of the base and an air cushion pod housed at the rear of the base, the air pod when inflated acting to raise the rear of the base off of the floor to reduce friction so that the chair can be rolled or pivoted about on the roller members.

Referring now in detail to the drawings, FIGURE 1 shows a dental chair generally indicated at and a console 12 which constitutes no part of this invention. Console 12 contains the equipment necessary for performing drilling, filling and extracting operations, a cuspidor and other associated dental apparatus (not shown). Chair 10 includes a seat portion 14, a tiltable backrest 16 and a pedestal 18 for supporting the seat above a floor surface 20. Pedestal 18 houses the controls and hydraulic system (not shown) necessary for hydraulically raising and lowering the dental chair or tilting backrest 16. A button panel 22 is incorporated into backrest 16 for activating the hydraulic equipment.

As shown in FIGURE 1, pedestal 18 is supported at its lower end on the air glide wheeled base of our invention generally designated at 30. In the present invention,

pedestal 18 is firmly fixed to base 30 and no provision is made for allowing the dental chair to swivel on the base or pedestal.

Referring now to the invention as shown in FIGURE 2, air glide base 30 is shown to include a downward opening housing 32. Housing 32 has a forward portion 34, a raised central portion 36 for supporting pedestal 18 and a rearward portion 38. As shown in FIGURES 2 and 3, forward portion 34 is provided with a plurality of spaced members 40 formed integrally with housing 32 for sup porting an axle 42. Journaled to either end of axle 42 are rollers 44 which extend slightly through the downward opening housing to support the forward portion of housing 32 above floor surface 20. Rollers 44 are preferably cylindrical, although other rolling members such as a ball and socket may be used in their place. Cylindrical rollers 44 are preferred because this configuration provides dental chair 10 with maximum support and stability. The cylindrical shape resists any force tending to move the base axially with respect to the rollers. Other rolling members such as ball and socket rollers, or casters may not provide this stability against axial movement. As will be seen from FIGURES 1 and 2, the axis of rotation of cylindrical rollers 44 is located far forward of pedestal 18 for purposes explained hereinbelow.

Formed integral with the rearward portion 38 is a generally semi-circular downward projecting lip 46 (FIG- URES 2-4). Lip 46 is adapted to rest on and frictionally engage floor surface providing a brake to effectively prevent movement of the dental chair. Thus, with lip 46 resting on the floor, the dental chair is maintained in a stable tripod supported position. Lip 46 forms the rear leg of the tripod and each of roller members 44 forms a forward leg.

Located within rearward portion 38 of housing 32 is a ground effect device generally designated at 50. Ground effect device 50 (FIGURE 4) is commonly known as an air pod having a cylindrical backing plate 52 firmly affixed to the under surface of rearward portion 38 and a flexible inflatable membrane 54 attached by heat sealing about the periphery of backing plate 52. Membrane 54 is attached at its center portion 56 to backing plate 52 by any suitable means such as a heat seal, and has a plurality of radially spaced openings 58 formed through the membrane for purposes set out hereinbelow. An inlet 60 extends through rearward portion 38 and backing plate 52 to permit the introduction of low pressure air between the backing plate and membrane 54 to inflate the membrane. For convenience, the controls to initiate inflation of the membrane can be included in button panel 22.

As shown in FIGURE 4, air which is introduced from a source (not shown) through inlet 60 and into the air pod inflates fabric-like membrane 54. Since the membrane is attached at its center portion to the backing plate, inflation of the membrane further causes it to assume a toroidal shape. Inflating the membrane further causes it to expand through the downward opening of housing 32 and bear against floor surface 20, lifting lip 46 off of the floor surface. Air escaping through radially spaced openings 58 forces its way between the membrane and the floor surface to form a thin film of air between membrane 54 and floor surface 20. This thin film of air greatly reduces the friction between membrane 54 and floor surface 20 which permits the chair to be easily moved about on cylindrical roller members 44 with a minimum of effort. Since only a portion of the entire combined weight of patient and chair is supported by air pod 50, the area of the air pod is greatly reduced thereby reducing the amount of escaping air.

With the air pod inflated, dental chair 10 remains tripod supported, each of the cylindrical roller members 44- continuing to form one leg of the tripod and the air pod now providing the third leg of the tripod. With this arrangement, dental chair 10 can be rolled forward or backward with a minimum of effort.

As stated hereinabove, the axis of rotation of cylindrical rollers 44 is well forward of the pedestal 18. With this arrangement and with air pod 50 inflated, the back section of the chair can be swung from side to side as desired to better. position the chair in relation to console 12 for performing the work required. This eliminates the need for having pedestal 18 swivel on base 30. Eliminating a swivel in base 30 provides a more rigid construc tion which is desirable for the safety of the patient. As shown in FIGURE 5, the axis about which chair 10 can be rotated is not fixed as is the case in chairs having their seat swiveled to a pedestal. Therefore, the dentist can select the point about which he wishes to pivot dental chair 10. For example, he can pivot the chair about one or the other of the cylindrical rollers 44, some point between these two rollers or some point which lies entirely outside of the base.

Thus, it will be appreciated that the present invention accomplishes its intended objects providing a dental chair which is completely stable yet which can be moved along a floor surface quickly and easily with a minimum of effort. Employing a ground effect device to greatly reduce friction allows the chair to be moved with a minimum of effort. Providing a pair of cylindrical roller members to carry a greater portion of the weight of the chair provides stability without sacrificing mobility. With air pod 50 deflated and with lip 46 resting on floor surface 20, a stable and effective brake is provided which prevents any unwanted or unexpected movement of the dental chair. Eliminating the need for a swivel also adds to the stability of the chair and eliminates the necessity of a locking device to keep the chair from swiveling. Furthermore, by moving the point about which the chair can be pivoted forward of the pedestal, the head and upper body portion of the patient can be moved through a relatively large arcuate distance while moving the lower body portion of the patient through a relatively small arcuate distance. With the pivot point located directly beneath the patient in pedestal 18 as taught by the prior art, both the upper and lower body portions of the patient moved through the same arcuate distance when the chair was pivoted. In the present invention, the chair can be pivoted away from console 12 to provide room for an assistant without having the lower body portion of the patient come in contact with the console.

We claim:

1. A movable stand for supporting a structure above a planar surface comprising:

(a) a unitary base platform having a first portion adapted to rest on said planar surface and a second portion;

(b) a pair of axially spaced rotable members journaled to said base platform adjacent said second portion for supporting the same above said planar surface; and

(c) an air pod device attached to said base platform adjacent said first portion for lifting said first portion 01f of said planar surface when air is supplied to said device wherein an air gap is formed between said device and said planar surface, whereby said stand is movable and interrupting the air supply to said device causes said stand to become immovable.

2. A movable stand as set forth in claim 1 wherein said air pod device is located at one end of said base platform and said rotatable members are located at another end of said base platform, said device and rotatable members together providing a stable, threepoint support for said base platform when air is supplied to said device for moving said stand along said planar surface.

3. A movable stand as set forth in claim 1 wherein said base platform is provided with a downward projecting portion located at one end of said base platform adjacent said first portion, said downward projecting portion being adapted to rest on and frictionally engage said planar surace, said projection and said pair of axially spaced rotatable members together providing a stable, three-point support for said base platform for immobilizing said stand when air is not supplied to said air pod device.

4. A movable stand as set forth in claim 1 wherein said pair of axially spaced rotatable members are journaled to a fixed axis lying substantially perpendicular to a line passing through the midpoint of said axis and the center of said air pod device.

5. A movable stand as set forth in claim 1 wherein said pair of axially spaced rotatable members are cylindrical rollers, the cylindrical shape of said rollers acting to resist movement of said stand about a vertical axis when air is not supplied to said air pod device.

6. In combination with a dental chair having a seat, a tiltable back rest and a pedestal for supporting said seat above a floor surface, an air cushioned wheeled base comprising:

(a) a downward opening housing having a central portion for carrying said pedestal, a rearward portion adapted to rest on said floor surface and a forward portion;

(1:) an air pod device attached within said housing adjacent said rearward portion, said device adapted to support said rearward portion above said floor surface wherein an air gap is formed therebetween when air is supplied to said device;

(c) a pair of rotatable members attached to said forward portion and extending through said downward opening to support said forward portion above said floor surface;

(d) said pair of rotatable members and the rearward portion of said housing resting on said floor surface providing a stable, immovable, three-point support for said dental chair when air is not supplied to said ground effect device; and

(e) said pair of rotatable members arid said air pod device providing a stable, movable, three-point support for said dental chair when air is supplied to said device.

References Cited UNITED STATES PATENTS 3,239,022 3/1966 Dolphin l25 X 3,254,733 6/1966 Deeley et al 180-123 3,261,177 7/1966 Am-ann et a1 180-125 X 3,326,311 6/1967 Jung 180-126 A. HARRY LEVY, Primary Examiner.