Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS3295621 A
Publication typeGrant
Publication dateJan 3, 1967
Filing dateApr 25, 1963
Priority dateApr 25, 1963
Also published asDE1429294A1
Publication numberUS 3295621 A, US 3295621A, US-A-3295621, US3295621 A, US3295621A
InventorsJr Haskin U Deeley, George H Stram
Original AssigneeDentists Supply Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Supporting base for chair and the like for gliding on a film of air
US 3295621 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

1967 H. u. DEELEY, JR.. ETAL 3,

SUPPORTING BASE FOR CHAIR AND THE LIKE FOR GLIDING ON A FILM OF AIR Filed April 25, 1963 :5 Sheets-Sheet 1 INVENTORS' I96 20o #ASK/N U. DEE'LEY, We. 32 gamma 57mm A; 589. 7 ma H. u. DEELEY, JR. ETAL 3,295,621 SUPPORTING BASE FOR CHAIR AND THE LIKE Jan. 3, 1967 FOR GLIDING ON A FILM OF AIR 5 Sheets-Sheet 2 Filed April 25, 1965 w www INVENTORS HAS/{IN U. DELY,JA, 6150/2 1 STEAM Jan. 3, 1967 H. u. DEELEY, JR. ETAL 3,295,621

SUPPORTING BASE FOR CHAIR AND THE LIKE FOR GLIDING ON A FILM OF AIR 3 Sheets-Sheet 5 Filed April 25, 1963 Q J v M m w l- ER NI-T W05 n muu 6 0d ma. 7 KR 2 U HG V.. B 2 2 4 9 J L n ATTORNEY United States Patent Ofilice Patented Jan. 3, 1967 3,295,621 fiUlPiQRTING 3155B I i/PR CHAIR AND THE LIKE FOR GLIDING ON A lt llLM OF AIR Haskin U. Deeley, .Ir., Baltimore, Md, and George H.

Stram, Hellarn, Pa, assignors to The Dentists Supply Company of New York, York, Pin, a corporation of New York Filed Apr. 25, 1963, Ser. No. 275,594 14- Jiaims. (Cl. 180-7) This invention pertains to a mobile chair construction and, more particularly, to a mobile chair of the type suit able for use by dentists in their dental operatory, by barbers and beauticians in their normal places of business, and by any other profession particularly under circumstances where a patient or patron normally is seated in the chair and it is desired to move the chair with the patient or patron in it from one location to another within the room where the chair normally is located, or from one room to another.

For many years, particularly dental and barber chairs, for example, have been used from a stationary location upon the floor of the dental operatory or barber shop. These chairs usually were of such nature that the seat portions, as well as the backs connected thereto, have been pivotally movable relative to the bases about a substantially vertical axis. In many instances, the backs and foot rests have been adjustably movable relative to the seat of the chair so as to dispose the patient or patron in various angles of sitting positions, as well as enabling them to be disposed substantially horizontally.

Chairs of this type also have been in common use which provide various means for elevating the seat to different vertical positions relative to the stationary base. Most such means are actuated by hydraulic cylinder units requiring either a hand pump or power-operated pump to actuate the piston of the unit and thereby elevate the seat of the chair relative to the base.

In barber shops and beauty salons, especially in regard to shampooing operations, at present it is essential to have the patron or customer sit in the chair while having the shampoo applied to their hair, and then the patron or customer must leave the chair and walk to a sink where they usually are seated upon a low stool while the shampoo is rinsed from their hair. Frequently, two or three such operations as this are required, including repeated applications of shampoo and repeated rinsings, all of which is of a nuisance character resulting, basically, from the fact that the chair is immovable in a horizontal, linear direction of any kind.

Modern trends in dental operatories strongly tend to the use of cabinet units arranged along certain walls of the operatory, including cabinets and units housed within or associated with cabinets, or supported on pedestals. Such cabinets or units contain the various hand instruments commonly used in dentistry such as syringes, pulp testers, cauteries, fluid-operated dental handpieces, and the like, and such cabinets sometimes provide for limited movement of a bank of such instruments relative to the cabinet.

Essentially, while the current trend in furniture motif in dental operatories is toward relatively fixed counters and cabinets along the walls of relatively compact rooms, the trend in instruments, such as Y-ray machines, lights, and other instruments of this general type, still definitely tends toward the use of swinging arms and linkages which, especially in contrast with the otherwise neat appearance of the cabinetry in the room appear to be somewhat awkward and out of place. Basically, it also is still necessary, in accordance with present practice, to bring the instruments to the patient rather than there being any concept of moving the patient with respect to the instruments,

except in regard to such movement as is afforded by the simple rotation of the chair about the vertical axis of its stationary base.

It is the principal object of the present invention to provide a chair for use by medical and dental patients, barber shop or beauty salon customers or patrons, or the like, and more particularly, to provide a base for chairs of this type which is mobile relative to the supporting surface such as the floor, particularly in horizon tal, linear movement of the chair base with respect to the floor, while also permitting movement of the chair about a substantially vertical axis either while the base is stationary or being moved linearly.

One of the principal advantages of providing for such movement of the chair as indicated above is that it permits flexibility in achieving the most desirable and efficient operating position both in regard to the operator and the occupant of the chair, for any given operation. Operation from the most efficient and/or comfortable position produces simplification of the operation, which is an objective of modern dentistry, as well as barbering and beauty shop operation, for example, and thereby results in minimum use of time and maximum economy.

Though pedestals which support certain equipment presently are employed which have casters to render them mobile in dental offices and also in barber shops and beauty salons, thus enabling the same to be moved to the patient or patron, there are a number of overriding advantages resulting from moving a chair, with the patient or patron in it, to certain units, instruments, or areas of an operatory, shop or salon. The more outstanding advantages are:

(1) Improved aesthetics resulting from the absence of casters, pivots and extending arms and existence of only minimum power conduits, tubes and similar service lines since these do not have to follow a movable chair to anywhere near the extent they are required relative to a movable pedestal type unit or instrument. Appearance further is enhanced due to leaving the cabinets, units, counters and the like stationary in the position best suited for them within a room, whereby service lines to them can be hidden to the rear thereof or within the walls.

(2) Maximum efficiency results from moving the patient or patron to instruments or units rather than vice versa because less total movement is involved while also providing greatest possible combination of desired related positions of the dentist or operator to the patient or patron, as well as any assistants involved in such operations.

(3) Maximum accessibility to wall or counter type cabinetry is afforded since, when a unit is moved from a position along a wall or from a counter to a chair, it frequently blocks other units or cabinet areas from accessibility.

(4) Improved traffic How in room is afforded, especially for a dentist or operator, as well as assistants due to maximum clear fioor space being provided when all or maximum number of units and instruments remain substantially within their normal positions along a wall or the like.

(5) Possibility of minimizing size of certain units and instruments due to there being substantially no need to move any of them from a stationary position to the chair, inasmuch as the chair is to be moved to the unit or instrument in accordance with the invention.

(6) A more orderly, departmentalized arrangement of a dental operatory, barber shop or beauty salon is possible due to positioning all necessary instruments and units for certain operations adjacent each other to conserve space and movement of the dentist or operator and assistants. For example, in a dental oflice, all the crown and bridge cabinetry, units and instruments can be mounted along one Wall, all the prosthetic units and equipment can be along another wall, all operative instruments and equipment along another wall, and X-ray and miscellaneous equipment can be grouped along still another wall.

Another object of the invention is to utilize air pressure to produce a film of air between the bottom of the base and a supporting surface, such as a floor, whereby the chair base as well as any chair connected thereto may be moved through the application of limited human force, applied in a horizontal direction against the chair seat or back to effect desirable rotation or linear movement of the chair and base relative to a floor surface.

A'further object of the invention is to provide powerdriven means within the base and connected with the chair seat supporting means thereon to elevate said supporting means, vertically, in opposite directions, within reasonable limits, such elevating means preferably being of the type which does not permit relative rotational movement between the chair seat supporting means and the base.

Still another object of the invention ancillary to the foregoing object comprises the provision of vertically movable guide means carried by the supporting means for a chair seat and movable relative to suitable hearings in the base for the chair, screw threaded means preferably comprising the mechanism by which the chair seat supporting means is raised or lowered relative to the base.

A still further object of the invention is to provide within the base power-driven means operable to produce a sufiicient supply of air under pressure quickly, and for reasonable periods of duration, in order to produce the air film upon which the base glides over a floor surface while being moved as desired, there also being self-contained power means for the chair seat elevating mechanism contained in the base.

One further object of the invention is to provide control means for the aforementioned power means within the base, preferably through the use of actuating means which, preferably, may be mounted upon the back of a chair so as readily to be manually operated, said actuating means being capable of raising or lowering the chair seat relative to the base, and also energizing the air pressure-producing mechanism to provide an air film beneath the base, usually only for a short period of time, and then discontinuing said supply of air at the end of such period to permit the base promptly to become stationary upon the supporting floor surface from gravity.

Details of the foregoing objects and of the invention, as well as other objects thereof, are set forth in the following specification and illustrated in the drawings comprising a part thereof.

In the drawings:

FIG. 1 is a side elevation of a base for a chair which is illustrated in full lines and an exemplary chair seat and back supported by said base is shown in broken lines.

FIG. 2 is a vertical sectional view through the base shown in FIG/1, on a larger scale than in FIG. 1, and showing various details of the mechanism included in the base.

FIG. 3 is a vertical side elevation of the chair base shown in FIGS. 1 and 2 but said section being taken at a right angle to the section shown in FIG. 2 and on a slightly smaller scale than in FIG. 2.

FIG. 4 is a top plan view of the base shown in FIGS. 1 through 3, said view being on the same scale as used in FIG. 3.

FIG. 5 is a fragmentary vertical elevation of a portion of the mechanism for elevating the chair seat-supporting means whichis movably supported by the chair base shown in FIGS. 1 through 4.

FIG. 6 is a top plan view, partly broken away to show details, of part of the supporting mechanism shown in FIG. 5.

FIG. 7 is a vertical sectional view showing a fragmentary portion of the peripheral structure of the chair base otherwise shown in sectional view on a smaller scale in FIGS. 2 and 3, the arrangement in FIG. 7 illustrating in exemplary manner the inflated condition of air discharge and seal means associated with the bottom of the chair base.

FIG. 8 is a fragmentary vertical sectional view of a portion of the screw threaded means operable to raise and lower the chair scat-supporting means relative to the base.

FIG. 9 is a fragmentary vertical sectional view showing a modified portion of the periphery of the base and also illustrating the structure of guide means associated with the base.

FIG. 10 is a partial top plan view of the mechanism for elevating the chair seat-supporting means.

FIG. 11 is a fragmentary vertical sectional view of the periphery of the base similar to FIG. 7, but the section being peripherally spaced from the section shown in FIG. 7 to show additional details.

FIG. 12 is an exemplary electric circuit diagram for the motors within the chair base and the control means therefor.

Referring to the drawings, and particularly FIGS. 1 through 3, the base 16 comprising the present invention preferably is in the form of a metallic casting which is somewhat bell-shaped to provide ample space for the housing of power-driven mechanisms of several different types enclosed therein and also provide an outwardly extending peripheral flange 12. The bottom surface of the base, at least in certain areas thereof, is engageable with a relatively fiat and horizontal supporting surface such as a fioor 14.

Supported by, and vertically movable in opposite directions relative to, the upper portion of base 10 is a head or header 16 comprising a chair seat-supporting means to which an exemplary combination chair seat and back 18 is connectable. It is to be understood that the exemplary showing of such a combination chair seat and back 18 in FIG. 1 is for illustrative purposes only and is not to be regarded as restrictive of the chair seats and/or backs which may be supported by the header 16. It also is to be understood that the base 10 may be employed to support a variety of different types of chair seats and/ or backs connected thereto, including among others, dental chair seats, barber chair seats, beautician chair seats, operating tables, and the like.

The base 10 is primarily intended to rest, by gravity, upon a supporting surface such as floor 14, without being anchored thereto in any way. The area of the bottom of the base is ample to permit very substantial movement of the combination chair seat and back 18 in various pivoted positions relative to base 10, particularly positions extending about a horizontal pivot, without danger of tipping or toppling the base 10 relative to supporting surface 14. Preferably, the upper surface of the peripheral flange 12 also extends outwardly in a radial direction at a relatively fiat angle with respect to the floor surface adjacent which it is disposed so as to form a minimum amount of obstruction in the event operators either accidentally or intentionally engage the flange with their feet.

Enclosed within the base 10 is effective mechanism to raise and lower the header 16 to which a chair seat is connectable. To stabilize vertical movement of the header 16, particularly when the weight connected thereto is not evenly distributed between opposite sides of the vertical axis upon which the header is movable, suitable guide means are provided. In the preferred construction thereof, said means comprise a pair of guide rods 20 which are connected at the upper ends thereof to header 16, as clearly shown in FIG. 3, said rods extending through vertical guide bearings 22 preferably formed in the upper portion of the casting comprising base 10. Under most normal conditions of operation, the guide rods 20 move at a rather slow speed relative to guides 22, whereby the guide bearings may be of a relatively simple journal-bearing type, of which various kinds are available including those which are impregnated with permanent lubrication. Bearings faced with self-lubrication type resins are suitable to minimize friction and sticking. It will be seen also that the guide rods 20 preferably are evenly spaced on opposite sides of the vertical axis of the header l6 and base it] especially as viewed in FIG. 3.

Connected at its upper end to the central portion of header 16 is a screw shaft 24 which, in the preferred construction of the arrangement illustrated herein, is stationary relative to the header. Associated with the screw shaft 24 is a ball-nut 26 affixed to the upper end of sleeve 28 which is rotatably supported by a speed reducing gear assembly 30, of suitable commercial type.

Extending transversely across the lower portion of base is a rigid diaphragm or partition 32 which preferably is braced by radial ribs 33 and has an opening 34 in the center thereof through which the lower end of the gear assembly M) is accessible after a bottom cover plate 36 is removed to expose the same, the cover plate being held in closed position by suitable screws 38.

Power means for the gear assembly 30 comprises an electric motor 40 which is supported adjustably relative to the gear assembly 3-0 by the following mechanism.

A supporting plate 42 which is provided with a seat 44 in its lower face, receives the upper end of the gear assembly 39 within said seat and the plate 42 otherwise is secured to gear assembly 30 by appropriate means such as set screws 46 or the like.

Fixed to plate 42, such as by welding, is a lower post 48 to which an upper post St) is connected so as to be vertically adjustable relative to the lower post by suitable means such as a slot 52 and clamping bolts 54. Connected to the upper end of upper post 50 is a horizontal bearing bracket 56 containing an anti-friction bearing 57. The upper end of a driven shaft 58 is received within the inner race of anti-friction bearing 57 and is fixed thereto for rotation therewith. A bronze journal bearing bushing 6i also surrounds the upper portion of shaft 58 to permit the rotation of an upper clutch member 62 relative to shaft 5% under certain circumstances to be described hereinafter. The clutch member 62 also is provided with a suitable seat to receive an input pulley 64 which preferably is keyed to the upper sleeve portion of clutch member 62 which is clearly illustrated in FIG. 5.

Connected to opposite sides of upper post 50 intermediately of the ends thereof are a pair of arms 66 which extend, at the outer ends thereof into suitable notches d8 formed within the periphery of a non-rotatable friction brake plate 76 which also serves in the capacity of a brake. Preferably, resilient bushings are interposed between the ends of arms 66 and notches 68 so as to minimize the effect of braking shocks from adversely affecting the plate 7%. A bronze thrust washer '72 also is disposed upon the clutch member 62 for direct pressure engagement with an annular pressure plate '74, there being a bottom clutch boss 76 extending through the central aperture of annular plate 74. The boss 76 also is annular to receive the shaft 58 and, in opposed portions of the lower face thereof, the boss 76 is provided with cam notches 7 3.

Keyed to shaft 53 directly below boss 76 is a lower clutch plate 8% which has an upper boss 82 complementary to boss 76 and boss 82 likewise is annular. At diametrically opposed portions of the upper face of boss 82 are V-shaped cams 84 which are complementary in shape to the cam notches 78. The pressure plate 74 and lower clutch plate 80 respectively are adjacent the upper and lower surfaces of brake plate 70 which is non-rotatably secured relative to upper post 50. Plate 86 is urged upwardly toward plate 74 by a compression spring 86 which surrounds the threaded portion 88 of shaft 58, upon which threaded compression collar 90 is mounted, whereby rotation of collar 90 in opposite directions respectively compresses or releases tension upon the spring 86 so as correspondingly to adjust the pressure with which the plates 6 74 and engage opposite sides of relatively fixed friction plate 7i Shaft 53 is provided at its lower end with an enlarged boss 92 having an axial bore formed upwardly therein to receive the upper end of power-input shaft 94 which extends upwardly from the gear assembly 30, the shaft 94 serving to drive the gears within assembly 3%) for purposes of rotating sleeve 28 which actuates ball-nut 26.

As seen particularly from FIG. 10, supporting plate 42 has a bracket arm 96 extending radially therefrom and rigidly connected thereto. Pivotally connected to the outer end of arm 96 is a bracket 93 which is rotatable about the axis of pivot pin 1%. Fixedly connected to bracket 98 is a U-shaped cradle 192 of conventional construction, the opposite arms of which contain arcuate seats Hi4 which receive the conventional mounting collars of the motor 4!). Customary clamping straps 106 also extend around said seats in the motor 40 and engage the opposite arms of bracket 102 so as to support the motor 40 in such manner that its axis is parallel both to the pivot pin and the power input shaft 94. Preferably, the conventional mounting means at opposite ends of the motor include rubber shock absorbing members which are directly engaged by the clamping means afforded by the opposite legs of cradle 192.

The upper end of the drive shaft 108 of motor 40 has a pulley 11d fixed thereto, and a flexible, endless belt 112 extends around pulley 111) and input pulley 64 which is associated with power-input shafts 9 F or purposes of placing the belt 112 under desired tension, it will be seen from FIG. 10 that bracket arm 96 is provided with a vertical extension 114 through which a set screw 116 threadably is mounted with an appropriate lock nut also mounted thereon. The outwardly projecting end of set screw lid engages an upright portion of bracket 98 to which the cradle 192 is connected. Accordingly, as the screw 116 is adjusted in opposite directions, the tension placed upon belt 112 accordingly is varied.

Attention now is directed especially to FIG. 5 relative to describing the function and operation of the clutch or brake arrangement comprising plates 74 and 8%, as well as friction brake plate 70. Limited axial movement is permitted between plates 74 and 81'), as now will be described, but relative rotation between said plates is prevented through the employment of a plurality of short pins 113 which are fixed at their upper ends to plate '74, while the lower portion of the pins 318 extend through complementary holes 129 formed in lower clutch plate 86'. In rest position, the spring 86 normally presses plate 80 upwardly against non-rotatable friction brake plate '70 and the latter is urged against pressure plate 74 that is disposed in vertically abutting relationship with thrust washer '72 carried by upper clutch member 62.

When reversible electric motor 40 is energized, it drives input pulley 64 which rotates clutch member 62 and boss 76 which is provided with cam notches 78 therein. The direction of rotation of motor 49 will dictate which of the angularly related faces of the cam notches 78 will engage corresponding faces of the cams 84. However, regardless of the direction of rotation of clutch member 62, carnming action will occur between notches 73 and cams 8d and cause limited axial movement of clutch plate 8i away from the friction brake plate 70. Also, a limited amount of self-aligning of the same with respect to the plates 74 and 80 is permitted especially by virtue of the resilient lining means within the notches 68 which receive the arms 66 that prevent rotation of plate 78.

Upon the release of the friction brake plate 70 by the lower clutch plate *80, as a result of the above-described camming action, the shaft 51; and the power-input shaft 94, to which the former is integrally connected by pin 122, may be driven freely and rotatably by input pulley 64, which is driven by motor 40. As long as the rotational torque upon pulley 64 is sufficient to retain the camimed-apart relationship of the plates 74 and 80 with regard to plate 71 such free rotation of shafts 58 and 94 will continue. However, as soon as the electric motor 4%} is shut oif by action of the control switch, to be described, the cams 84- will advance slightly in the direction of rotation so as again to be fully disposed within the opposed cam notches 78, thereby permitting the spring 86 to bring clutch plate 81) firmly into contact with the underside of friction brake plate 70 and thereby force the same into firm frictional engagement with the pressure plate 74, thus bringing the rotation of shafts 58 and 94 to a sudden stop, which is the principal object of the clutch and brake mechanism described above. Such arrangement insures very close control of the vertical movements of the chair seat-supporting header 16 and any chair seat and/or back assembly connected thereto.

Details of the ball-nut 26 are shown in FIG. 8 wherein the screw shaft 24 and rotatable sleeve 28 are both shown though only in fragmentary manner. The spiral groove 124 on the shaft 2-4 has a configuration in cross-section which is complementary to the diameter of the spiral row of balls 1 26. Nut 26 also has a spiral groove 128 that is complementary to the groove 124 in shaft 24-, whereby approximately one-half of each of the balls 126 are disposed respectively within the groove 128 of the nut 26 and groove 124 of the shaft 24. As the nut 26 is rotated by driven sleeve 28 which is connected to and supported by gear assembly 30, the row of balls is fed from one end of the nut to the other through the medium of by-pass tube 130, which is integrally connected to the nut. The movement of the balls through the tube 130 for reception by the mating grooves 124 and 12-8 will be in one direction when the screw 24 is being elevated and in the opposite direction when the screw 24 is being lowered.

Since there is no practical Way of predetermining how much an attendant will want to raise or lower the seat supported by base 10, it is contemplated that the control means, to be described, for starting and stopping motor 40 will either be manually or foot controlled and, as long as the control switch is held on, the chair will either be raised or lowered, depending upon the direction of rotation of motor 40.

The present construction also preferably includes u'pward movement-limiting switch means, such as an exemplary electric switch 132, shown in FIG. 3, and conveniently located on the interior of the hollow housing comprising base 10. Said switch has a movable actuating member which is engageable by any appropriate means movable in elevating direction with the elevating mechanism for the chair, such as detent 134 on the lower end of one of the guide rods 2t). A similar downward movementlimitin-g switch 136 appropriately is mounted in the lower portion of housing and supported by suitable bracket 138, for example, carried by partition 32. The actuating member of switch 136 is engageable by detent 134 when the seat-supporting and guiding means, which is vertically movable, reaches the lower limit of its intended travel, thereby to shut off the motor 40 and prevent any damage to the driving mechanism.

Base moving mechanism Contrary to current practice and particularly for adapting the chair seat-supporting base to linear, as well as pivotal, movement within a substantially horizontal plane comprising, for example, the supporting floor surface 14, the base 10 is constructed to include, preferably, selfcontained means to generate air pressure and distribute the same at least around the periphery of the base and discharge the same from the bottom of the base, downwardly against the supporting floor surface, for example, so as to provide a film of air between the base and the supporting floor surface. By such arrangement, the base, as well as the chair seat and back connected thereto,

55 readily may be moved either in straight or curved linear directions, as well as being rotated about a substantially vertical axis, either while otherwise being moved, or not.

The amount of human force necessary to effect such linear or rotatable movements of the chair and base which supports the same is negligible. By the employment of means to produce such air film between the base and supporting floor surface, a number of advantages result, such as the elimination of any need for casters and movement-controlling means therefor, or any other similar type of supporting means which would permit linear and rotatable movements of the base relative to the supporting floor surface.

By employing the air means comprising an important part of the present invention, one of the principal attributes resulting therefrom is that, immediately at the end of the desired movement, the chair base will come to rest upon the supporting surface as soon as the power means which generates the air pressure is shut off. This is assured by the weight of the chair base, the chair, and the occupant, as well as the fact that the air film, which normally is created between the bottom of the base and the supporting floor surface, need only be quite thin, especially since the air discharge mechanism, tobe described, preferably is of a highly flexible nature so as to provide a seal which operates to permit substantially even discharge of air at substantially all circumferential locations around the base, while also permitting the seal to conform to irregularities in the supporting floor surface, at least within reasonable limits. This arrangement comprises one of the most advantageous features of the invention in that it results in the maximum use of minimum air pressure and volume due to minimizing wasteful leakage of air. In effect, the arrangement also comprises an air bearing of a flexible type to permit conformity to irregular surfaces such as a floor or the like.

The housing 10 is provided, preferably in the rear wall thereof, with an inlet opening 140, which communicates with an annular chamber 142 which has, substantially centrally thereof, an air compressor 144, which preferably is of the multi-stage type, provided with peripheral discharge ports 146. The rotatable impeller of the coinpressor is driven by an electric motor 143, which preferably is directly connected to the same to provide compactness. The shell or outer casing of the compressor 144 preferably is seated within a resilient gasket to minimize the transmission of vibrations of the compressor to the base, all other portions of the compressor and its motor preferably being out of direct or rigid metallic engagement with the base. To add further stability to the mounting of the compressor 144, an additional resilient gasket 152 also is disposed between the housing of the compressor and the annular diaphragm 154, which defines the inner extent of the annular chamber 142.

Both for appearance, as Well as efficiency, the inlet to the compressor 144, which is in the outermost end thereof, is shielded by a preferably attractive, porus cover 156, which is shown in exemplary manner in FIG. 2. It is to be understood that, rather than being a sheet of porous fabric, for example, said cover may be of appreciable thickness and additionally serve as a sound mufile.

The annular chamber 142 serves in the capacity of a plenum chamber, which, at the lower end thereof, communicates with the annular distribution chamber 158, the upper wall of which is formed by the peripheral flange 12, and extending downward from such flange are substantially concentric annular walls and 162, the lower surfaces of which preferably are within the same horizontal plane.

An annular plate 164 extends across the bottom surfaces of the annular walls 160 and 162, said plate completing the annular distribution chamber 158, which, essentially, comprises a manifold, discharge from which is etfected evenly, in a circumferential direction and adjacent the periphery of the base 10, by means of a series of air discharge ports 166 which act as metering means. Said ports are of suitable size and are spaced, preferably evenly, in a circumferential direction, to provide a relatively even distribution of air, under pressure, which is applied downwardly from the bottom of the base 11) against a combination porous air discharge and sealing member 168, which preferably is very flexible and sheetlike.

The member 168 may be formed from any suitably porous and flexible material, such as woven fabrics, of which muslin or sailcloth are two suitable specific examples. However, there are certain porous synthetic resins which may be made in sheet form to serve suitably as such air discharge and sealing member. Such resins should be adequately flexible that they will operate to conform readily to all reasonable irregularities within the floor surface 14, for example.

The principal function of the member 168 is to distribute air evenly, essentially by diffusion through perforations which are highly dispersed and preferably are openings of small sizein member 168, said perforations preferably being disposed within a relatively confined annular area directly beneath the member 168 and between said member and the floor surface 14, whereby economic use is madeof the air from the distribution chamber 158. Further, by discharging said air adjacent the periphery of the base 10, maximum efficiency also results due to the utilization of a maximum lever arm in elevating the base. slightly above the floor surface so as to effect ready glidingof the base over the floor surface upon the film of air discharged evenly and uniformly through the porous discharge and sealing member 168.

Ineffect, the air distributed by the member 168 somewhat works against itself, in that the air which has immediately been discharged through the porous member against the floor surface creates the air film desired to effect the gliding movement of the base, whereas the air pressure against the inner surface of the member 168 tends to force the member against the floor surface and thereby effects a seal against which the discharge film of air must operate.

The air discharge and sealing member 168, which preferably i formed from flexible, porous sheet material, inherently is flat and complementary in shape at its outer edge substantially to the periphery of the flange 12 of base 10. In the specific illustration of the periphery of the base 111, in plan view, as shown in FIG. 4, it will be seen that said base substantially is circular in shape. To form the flexible member 168, a piece of suitable size and shape of said material is cut from a supply sheet slightly larger in a radial direction than the shape of the periphery 12 of the base in order that the outer edge 178 may be tucked inwardly around a metal clamping ring 172. Said ring 172 preferably is complementary to the outer edge of the periphery 12 of base 11 and is secured to annular plate 164 by a limited number of circumferentially spaced screws 174, which are countersunk into plate 164 and extend down through threaded holes in the clamping ring 172, as shown in FIG. 11.

The primary purpose of screws 174 is to prevent ready separation of the clamping ring 172 from plate 164, especially when connecting said plate and the porous member 168 assembled therewith to the bottom of the periphery 12 of the base and also removing it therefrom. Especially to prevent damage to the flexible sheet-like member 168, and also to enhance the sealing properties thereof with respect to a floor surface, there is a ring of felt-like material 176, of any suitable nature, either of synthetic or natural material, cemented to the lower surface of clamping ring 172 so as to be disposed between said ring and the periphery of the porous member 168 against which ring 172 would abut, were it not for the presence of the felt ring 176, especially when the base is at rest upon the floor surface.

The flexible, porous member 168 i annular in plan view and substantially of an even width in a radial direction. The inner edge of said member is clamped to the lower surface of annular plate 164 by another clamping ring 178, preferably of metal. Said ring is clamped against the inner periphery of the annular plate 164 with the inner peripheral edge of member 168 clamped there between by a series of peripherally spaced screws 180, which extend through suitable holes in ring 178 and plate 164. Screws 180 threadably engage nuts 182 which are received within appropriate holes or cavities 184, formed within the diaphragm 32, and are securely fixed against rotation with respect to plate 164 by appropriate spot welding, or the like.

Secured to the outermost surface of plate 164, so as to be in vertical alignment with the vertical flange of base 10, as shown in FIG. 7, is another clamping ring 186that is welded or otherwise appropriately connected to plate 164 so as to be movable therewith as a unit. The ring 186 and plate 164 are provided with a plurality of axially aligned holes 188, which are spaced evenly in a circumferential direction around the ring 186, and at least the portions of the holes in ring 186 are threaded.

The annular plate 164, the flexible porous air-discharge and sealing member 168, and the various clamping rings 172, 178 and 186 carried by said plate, comprise a unit which is connectable to and removable from the base 10 as a unitary assembly, and especially from the flat bottom surface 191) thereof, which is complementary to the upper surface of plate 164, as can be readily appreciated from FIG. 7. Attachment of said unit or assembly to and removal of the same from the peripheral flange 12 of the base 11) is accomplished, preferably from the upper surface of flange 12. Two concentric, circular rows of headed screws 192 and 194 respectively extend substantially vertically through the vertically depending circular flanges which respectively are partially defined by annular walls 160 and 162. The heads of the screws 192 and 194 preferably are countersunk into the upper surface of the flange 12, while the lower ends thereof respectively are threaded into the holes 188 in clamping ring 186 and threaded holes 196 formed in clamping ring 172. An exemplary, circularly spaced arrangement of bolts 192 and 194 is shown in FIG. 4.

By removing the screws 192 and 194 from their engagement with the clamping rings 186 and 172 respectively, the air-discharge and sealing unit or assembly may be removed easily and readily from the bottom surface 1% of the base 10 and, if, for example, replacement of the porous member 168 is required after an extended period of use, said assembled unit may be returned either to the service depot or the manufacturer for replacement under precise, factory-controlled conditions, thereby assuring maximum in workmanship in the product. Meanwhile, either a new unit or factory rebuilt unit may be installed in the matter of a few minutes on the chair base, and thereby restore the base to full operative condition with respect to the air-discharge feature of the base.

Replacement of the porous member 168 at the factory or service depot is accomplished quickly and inexpensively, requiring only the removal of the limited number of screws 174 and all of the screws 1811, thereby completely freeing the material 168 from plate 164, following which a new sheet of material is installed by being clamped to the plate 164, the new sheet 168 preferably being cut to size at the factory and maintained in stock either there or at the service depot so as to insure uniformity of positioning, quality, and ultimate operation for air distribution and cushioning purposes.

In operative use, there actually is very little wear sustained by the member 168, since, when the base and chair carried thereby are moved linearly or rotatably within a substantially horizontal plane parallel, for example, to the floor surface 14, there is a film of air between the floor surface and the bottom of the member 168. When the base is stationary relative to the floor surface, the

1 1 ring of felt 176 i disposed between any metal portions of the base and the inner surface of member 168. Also, in clamping the opposite edges of the porous member 168 to the plate 164 through the means of clamping rings 172 and 178, the edges of said rings which engage the clamped portions of the member 168 preferably are somewhat rounded, thereby minimizing any cutting or abrasion which might otherwise be sustained by member 168 in regard to engagement thereof by the clamping rings 172 and 178. The clamping ring 186, at least in accordance with normal intended operation of the mechanism, will never come in contact with member 168.

In order to assure, as far as reasonably possible, that there will be no objectional extent of canting of the base relative to the floor surface 14 while moving especially in linear directions over such surface, and particularly as a result of pushing horizontally upon the upper portion of the back attached to the chair seat 18, the outer edge of the peripheral flange 12 of the base is provided with one of a plurality of embodiments of means, which are intended to be employed to prevent any impedance in the movement of the chair base relative to the floor surface as a result of any canting of the base which might occur from such movement.

One embodiment of such means is illustrated in FIGS. 2, 3 and 7, wherein it will be seen that the outer periphery of annular plate 164 extends beyond the periphery of flange 12 a limited extent and is downwardly bent to form a guide flange 198. To enhance the guiding function thereof, with respect to the floor surface, however, the entire periphery of said flange preferably is covered with a molded annular member 200, preferably formed from a suitable synthetic resin having self-lubricating properties so as to provide substantially no friction, several com mercial varieties of such suitable resin being sold under the trade names Teflon, Delrin, Nylatron, and Nylon. All of these materials have the general property of being self-lubricating so as to impart substantially no friction against a surface with which it is slldably brought into contact.

The lowermost surface of the annular ring member 200, which preferably is entirely within a common plane, is slightly below the lowermost surface of the air-discharge and sealing member 168 when the chair is at rest, i.e., as illustrated in FIG. 2, whereby the base actually will rest upon ring member or rim 200. It will be appreciated that in the corresponding, enlarged, sectional view of the peripheral flange 12 shown in FIG. 7, the porous member 168 is disposed in exemplary, inflated condition as when the normal air pressure is being exerted thereagainst for purposes of permitting linear or rotatable movement of the base and chair connected thereto. It will be understood, of course, that there will be a relatively thin film of air also between the member 168 and floor surface14, which is not illustrated in FIG. 7, but, nevertheless, is present during such operation. When member 168 is thus inflated to float the base 10 as described, the rim 200 is spaced slightly above the floor surface 14, as shown in exemplary manner in FIG. 7 but if slight tilting of the base 10 occurs, the rim 200 will engage the floor surface and prevent the periphery of the base from impeding lateral movement of the base.

Another embodiment of guide means is illustrated in vertical sectional elevation in FIG. 9 and in plan view in FIG. 4. In this embodiment, a reasonable number of projecting bosses 202 are spaced circumferentially around the outer terminal edge of peripheral flange 12, as shown in FIG. 4. Referring to FIG. 9, it will be seen that each boss is provided with an internal cavity 204 which contains a compression spring 206 and a hardened metallic ball 208 of substantial diameter, said ball being held against complete removal from the cavity 204 by any suitable means such as by an intur-ned terminal rim 210 depending from the boss 202, or the like.

The force of the spring 206 and the diameter of the ball 208, as well as the position of the ball within the cavity 204 all are such as normally to maintain the ball at least lightly in contact with the floor surface at least when the base is stationary and the member 163 is uninflated. By such an arrangement, when the member 168 is inflated so as to assume the exemplary position thereof with respect to the base as illustrated in FIG. 7, the position of each ball 208 in the bosses 202 is such that if canting of the base occurs during linear or rotatable movement of the base with respect to the floor surface 14, one or more of the balls 208 will engage the floor surface and tend to prevent any retarding in the movement of the chair base relative to the floor.

Control arrangement The operation of motor 40, in either of its directions of rotation, as well as the operation of motor 148, which respectively control the raising and lowering of the seatsupporting header 16 and the air compressor 144, are controlled preferably from a single switch box 212 which, for convenience, may be mounted upon the rear surface of chair back 214 for ready engagement by the hand of the operator, or at other suitable locations on the chair seat or back, the base, or at remote locations depending upon the desires and needs of the dentist, operator, assistant, or otherwise. The specific control means preferably comprise an exemplary double throw switch 216, which controls motor 40 for either desired rotary direction, and a simple ON-OFF switch 218 both of which are illustrated in the circuit diagram of FIG. 12. It will be assumed that an electric conduit will be provided to extend to a suitable source of power such as a wall or floor electric outlet, and appropriate conductors will lead from said conduit to the various switches and, fro-m said switches, to the motors in accordance with the wiring diagram of FIG. 12. The switch 216 preferably is marked UP, OFF and DOWN, while switch 218 is marked ON and OFF.

When switch 218 is moved to ON position, the motor 148 will commence to operate and will cause the air pressure to be generated immediately for discharge into annular chamber 142 and, from there, into the annular distribution chamber 158 for discharge into the space immediately below plate 164 so as to inflate the air-discharge and sealing member 168, thereby causing a film of air to be disposed between said member and the floor surface. Such film will permit ready rotatable or linear movement,

either in straight or curved directions, of the base relative to the floor surface 14, simply by the application of a limited amount of manual force, for example, against the back 214 of the chair seat 18 and thereby move the chair seat and a customer or patient therein to any desired new position within the operatory, barber shop, beauty salon, and otherwise. At the completion of such movement, switch 218 is moved to OFF position to stop motor 148.

When motor 148 is stopped, the air pressure within the air circulating system immediately will be dissipated sufliciently that member 168 will become deflated and the base 10 will come to rest, by gravity, in the new location, in which position it will remain until subsequently moved again. During the time the member 168 is inflated, the base 10, chair seat and person supported thereby can be rotated about a vertical axis or moved in any linear direction desired.

The vertical movement of the seat-supporting header 16 as well as the chair seat and any person occupying the seat is controlled in its movements in reverse directions by the switch 216, shown in FIGS. 1 and 12, which is connected to the reversible circuits of the motor 40 which, as explained above, is of the reversible type. The motor will continue to operate in the selected direction as long as the switch 216 is held in the UP or DOWN position but, immediately upon movement of the switch actuator to OFF position, the motor Will stop. Should the elevating or lowering of the chair seat continue to either its upper or lower extreme positions, the safety or limit switches 132 and 136 will be engaged, as described hereinabove, and automatically disconnect the motor circuit when the actuating member of one or the other of said switches 132 or 136 is engaged by, for example, the actuating detent 134 carried by one of the guide rods 20.

While the chair base illustrated in the drawings and described hereinabove has included a self-contained air compressor 144 to provide means by which the base and all that is carried thereby may be suspended upon a film of air so as readily to be moved horizontally or rotated about avertical axis, it is to be understood that air under suitable pressure may be supplied, from an external source and conducted to the annular distributing chamber 158, for example, through the use of a suitable control valve. Such valve, for example, could be solenoid-actuated and controlled, if desired, by switch 218. The conduit to supply such air to the chair base could be of a suitable flexible nature and rest upon the floor surface, conceivably also being in conjuncture with the flexible electric conduit leading to the chair base from a power outlet, as described above.

In view of the foregoing, it will be seen that inasmuch as the means carried by the base for raising and lowering a chair seat to be supported by the header 16 thereon is such as to embody laterally spaced vertical guide members 20 which are on opposite sides of centrally positioned screw mechanism for raising and lowering the chair seat, no means are provided for effecting rotation between the chair seat 18 or the header 16 which supports the same, on the base 10. Another reason for not providing for any such rotatability of the seat relative to the base is that, by the arrangement just referred to, it is possible to direct the movement of the chair base 10 relative to the supporting floor surface, for example, by engagement of the back 214 which is connected to the chair seat 18 for example. However, rotation of the chair seat 18 to any desired position about a vertical axis, for example, readily is achieved simply by applying the air pressure to the air-discharge and sealing member 168 so as to furnish a film of air beneath the chair base adjacent the floor surface, either for a momentary period or longer, which permits the chair base to glide readily and easily over the floor surface, either in linear directions or for revolving movements about a substantially vertical axis. Stabilizing of such movement of the chair base is accomplished by any one of a number of floor-engageable stabilizing means adjacent the base of the rim, such as peripheral rim member 200 or the means 202 shown in FIGS. 4 and 9.

While the invention has been described and illustrated in its several preferred embodiments, it should be understood that the invention is not to 'be limited to the precise details herein illustrated and described since the same may be carried out in other ways falling within the scope of the invention as claimed.

We claim:

1. Mobile supporting means for a chair seat comprising in combination, a base arranged to be moved along and supported upon a floor surface, supporting means on the upper portion of said base arranged to have a chair seat connected thereto, air distributing means in the lower portion of said base, means to supply said distributing means with air under pressure, a substantially circular and ring-like rigid plate member having air discharge port means therethrough, means detachably connecting said plate member to the lower portion of said base, porous flexible sheet-like air discharge means complementary in shape to said plate member and extending over the lower surface of said plate member adjacent the periphery thereof, means to control the supply of air to said porous means, and means connecting the periphery of said porous flexible air discharge means to the periphery of said plate member, said porous flexible air discharge means being inflated a limited amount away from said plate member when air under pressure is discharged from said air distributing means through said discharge ports and against said porous flexible discharge means to cause air to be discharged therethrough and form a film of air between the same and a floor surface over which the mobile supporting means may glide upon said film, said detachable connecting means permitting said plate member and porous air discharge means carried thereby to be disconnected from said base as a unit.

2'. The mobile supporting means according to Claim 1 in which said air discharge ports in said plate member comprise metering means and are of suitable size and location in said plate to provide substantially even air pressure upon the entire inner area of said porous flexible discharge means.

3. The mobile supporting means according to claim 1 in which said air distributing means in the lower portion of said base comprises a manifold chamber opening downwardly from said base, and said plate member extending across the lower face of said manifold chamber and permitting discharge of air under pressure through said port means in said plate member to the inner surface of said porous flexible discharge means.

4. The mobile supporting means according to claim 3 in which the lower portion of said base is broader than the upper portion thereof and is of sufiicient cross-sectional dimension and shape to provide adequate support for a chair seat and occupant upon a floor surface, said manifold chamber in the lower portion of said base being adjacent and extending substantially around the periphery of said base and the shape of said plate member being complementary to the periphery of said lower portion of said base.

5. The mobile supporting means set forth in claim 4 further including guide means for said base carried thereby around the periphery thereof and having lower guiding surfaces at least no higher than the plane of the bottom of said base when at rest upon a floor surface, whereby said guide means serves to prevent halting engagement of the peripheral edge of said base with a floor surface While moving thereover.

6. The mobile supporting means set forth in claim 5 further characterized by said porous air discharge means being inflatable downwardly from the bottom surface of said base a limited amount, and said guide means engageable with such floor surface when said air discharge means is uninflated and spaced slightly above such iloor surface when said air discharge means is inflated as when said base is gliding upon a film of air relative to such floor surface.

7. The mobile supporting means acording to claim 3 in which said means to supply said air distributing means with air under pressure comprises an air compressor and power means to operate it carried by said base, said compressor discharging into said air distributing means when operating.

8. The mobile supporting means according to claim 1 further including guide means extending vertically relative to said base and connected to said supporting means for a chair seat and operable to guide said supporting means for vertical movement in opposite directions relative to said base, said guide and supporting means including means preventing rotation thereof relative to said base and said base also including power means interconnected to said supporting means for a chair seat and operable when energized to move the same vertically as aforesaid, whereby when a chair seat is attached to said supporting means it is non-rotatably but vertically adjustable relative to said base and said connected base and chair seat may be moved horizontally and pivotally about a vertical axis relative to a floor surface when said base is supported upon a film of air.

9. The mobile supporting means according to claim 8 in which said guide means comprises a plurality of interengaging transversely spaced vertical guide bearings 15 and rods slidable in said bearings, said bearings being carried by said base and said rods being connected and depending from said supporting means for a chair seat.

10. The mobile supporting means according to claim 9 in which said power means is a reversible electric motor and including limit switches connected in the power circuit to said motor and supported by said base means in vertically spaced relationship for engagement by actuating means fixed relative to said seat supporting means and engageable with said switches at the opposite limits of desired vertical movement of said seat supporting means relative to said base.

11. The mobile supporting means according to claim 9 further including a chair seat connected to said supporting means, a chair back connected to said seat and normally extending vertically therefrom, and manually operable control means for said power means for said supporting means carried by said back of said chair seat for convenient engagement by the hands of the operator.

12. The mobile supporting means according to claim 9 further including a chair seat connected to said supporting means, a chair back connected to said seat and normally extending vertically therefrom, and manually operable control means for said power means for said air compressor carried by said back.

13. Mobile supporting means movable relative to a substantially horizontal supporting surface such as a floor and comprising a base, means on said base to receive articles or persons to be supported thereby, sheet-like porous flexible means on the bottom of said base, means to direct air under pressure to said porous flexible means for discharge therethrough onto such supporting surface and provide a film of air permitting said base to glide over said surface, means to control the supply of air to said porous flexible means, plate means complementary in shape to the bottom of said base and disengageably connected thereto, means connecting said porous flexible means to said plate means and said plate means having air passages therethrough to discharge air onto said porous means, the periphery of said plate means comprising a flange 16 extending radially beyond said base, and stabilizing guide means connected to the rim of said flange for guiding engagement with a supporting surface when said base is tilted relative to said surface.

14. The mobile supporting means set forth in claim 13 further characterized by said guide means comprising antifriction type synthetic resin affixed at least the lower peripheral surface of said plate means, the lower surface of said guide means normally being spaced above a supporting surface when the base is gliding thereover upon a film of air but slidably engageable with such surface when said base is tilted from its normally intended position of substantial parallelism of the bottom thereof with such surface while gliding thereover.

References Cited by the Examiner UNETED STATES PATENTS 1,582,280 4/1926 Koken 297348 2,743,787 5/1956 Seck. 2,832,986 5/1958 Seek. 2,938,590 5/1960 Barnett. 3,082,836 3/1963 Billman. 3,096,728 7/1963 Amann et al 1807 X 3,097,718 7/1963 Jay et al. l807 3,101,125 8/1963 De Ridder 180-7 3,104,496 9/1963 Macks 1807 X 3,119,598 1/1964 Petersen et al. 180-7 3,161,247 12/1964 Mackie 180-7 3,185,238 5/1965 Coates 180-7 3,232,366 2/1966 Cockerell 1807 3,243,004 3/1966 Mackie 180-7 FOREIGN PATENTS 225,214 3/1926 Great Britain. 860,781 2/1961 Great Britain.

A. HARRY LEVY, Primary Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1582280 *Jan 21, 1924Apr 27, 1926Koken Walter FBarber's chair
US2743787 *Apr 7, 1954May 1, 1956Hoover CoAir supported cleaner with diffuser
US2832986 *Apr 6, 1956May 6, 1958Hoover CoConvertible air supported suction cleaner
US2938590 *Dec 9, 1957May 31, 1960Henry W BarnettConveying device
US3082836 *Dec 5, 1960Mar 26, 1963United Aircraft CorpLifting device
US3096728 *May 1, 1961Jul 9, 1963Gen Motors CorpHigh speed land transportation system and vehicle therefor
US3097718 *Jun 25, 1958Jul 16, 1963Ford Motor CoSupport system
US3101125 *Jul 27, 1960Aug 20, 1963Reynolds Metals CoGround effect machine
US3104496 *May 26, 1958Sep 24, 1963Fred Macks ElmerApparatus for providing mobility of a figure toy
US3119598 *Aug 28, 1962Jan 28, 1964Douglas Aircraft Co IncAir film supported weighing jack
US3161247 *May 19, 1961Dec 15, 1964Gen Motors CorpAir cushion load supporting device
US3185238 *Oct 3, 1960May 25, 1965Douglas Aircraft Co IncPneumatic loadlifting and translating means
US3232366 *Jun 13, 1962Feb 1, 1966Hovercraft Dev LtdGround effect machine with permeable material support member
US3243004 *May 2, 1962Mar 29, 1966Gen Motors CorpDiaphragm construction for air cushion device
GB225214A * Title not available
GB860781A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3347330 *Jul 12, 1965Oct 17, 1967Dentists Supply CoSelf-leveling air supported mobile chair base
US3754617 *Feb 23, 1971Aug 28, 1973Bertin & CieDevice for partitioning a space between two bodies in relative motion to each other
US4552403 *Sep 29, 1983Nov 12, 1985Hamilton IndustriesPower-operated medical examination table
US4993736 *Sep 22, 1989Feb 19, 1991Mangar Aids LimitedWheelchair apparatus
US20030187433 *Mar 28, 2002Oct 2, 2003A-Spine Inc.Rotary device for fixing vertebrae under treatment
EP0406100A1 *Jun 26, 1990Jan 2, 1991PROCEDES FRANCE TRANSPORT, Société Anonyme dite :Vehicle or load supporting unit with device of the air-cushion sustaining type
WO1991000204A1 *Jun 26, 1990Jan 10, 1991Procedes France TransportLoad carrier vehicle for assembly with lifting members of air cushion type
U.S. Classification180/124, 297/344.23, 384/124, 297/344.19, 188/166, 188/72.1
International ClassificationA47C1/06, A47C1/00, A47B91/00, A47C3/20, A61G15/00, B60V3/00, A47C3/30, A61G15/10, B60V3/02
Cooperative ClassificationB60V3/025, A61G15/10, A47B91/002, A47C3/30, A47C1/06
European ClassificationA47C1/06, B60V3/02B, A47C3/30, A61G15/10, A47B91/00B