DETAILED DESCRIPTION OF THE INVENTION

[0021] FIGS. 1, 1A and 1B show a typical dental chair 10, which in standard fashion has the following patient-contacting portions supported on a pedestal 20 secured to the floor with a stable base 22: a headrest 12, a backrest 14, an elongated seat 16 with toeboard portion 16a, and armrests 18. These patient-contacting portions are adjustable and separately articulated with manual and/or motor adjustments in known manner. Power adjustment mechanisms are usually located in pedestal 20, powered from a standard electrical supply, for example through a floor-mounted power/control unit 24, and controlled by the dentist or the patient 32 through foot-operated controls 24a and/or a handheld remote control unit 26.

[0022] FIG. 1A shows the rear of the backrest 14, supported on a metal or plastic frame 30 having a column 30a for adjustment mechanisms or linkages and any electrical wiring needed for the mechanisms or linkages that are powered.

[0023] FIG. 1B illustrates a patient 32 reclining on chair 10. The contours of headrest 12, backrest 14, and seat 16 are carefully designed to comfortably support the patient without strain or pressure points, and to position the patient so that the dentist and hygienist may work conveniently and comfortably on the patient. The importance of the dentist's comfort and convenient access to the patient should not be underestimated, and dental chair manufacturers are believed to design and advertise their chairs with these factors in mind. In accordance with a prior art suggestion, a massage pad 34 is shown laid on chair 10 in an effort to make patient 32 even more comfortable. However, it will be readily apparent that whatever questionable effect the pad 34 may have on the patient's comfort, the thick pad significantly alters the carefully designed contours of chair 10, thereby altering the positioning of the patient and the dentist's access and comfort. It has been found that the use of such pads is neither practical nor comfortable for the dentist. It has further been found that the fabric coverings of such massage pads are not easily or properly cleaned between patients, whereas the smooth, vinyl-like coverings of dental chairs are designed for quick and simple cleaning and asepsis.

[0024] FIGS. 2 and 3 illustrate dental chair 10 modified according to the invention with a backrest 114 having an internal massage mechanism that leaves the contours and surface of the backrest and the rest of the patient-contacting portions of the chair unchanged. Backrest 114 can be a standard backrest like that shown above at 14, subsequently modified to contain a massage mechanism, or can be built at the factory with the massage mechanism already in place. Although other patient-contacting portions of chair 10 can be modified or built with similar internal massage features, backrest 114 is the preferred portion of the chair for this feature because of its primary support of the patient's back and shoulders and its typical separation/separability from the other portions of the chair. The separation of backrest 114 from headrest 12 insulates the headrest (and the patient's mouth) from vibration, which would interfere with the dental work.

[0025] FIG. 2 shows patient 32 receiving a relaxing massage from backrest 114 as he reclines in chair 10. FIG. 3 shows backrest 114 removed from frame 30 and modified with an internal massage mechanism. Although a preferred embodiment of a massage mechanism for backrest 114 is described below, it will be understood by those skilled in the art that arrangements and components other than those shown in this preferred example can be used to provide backrest 114 with a massage capability.

[0026] FIG. 4 schematically shows one possible and preferred layout of massage components built into backrest 114, with two massage motors 116, a heating pad 118, and a pressure-activated heating pad switch 119 turned on by the weight of a patient against the backrest. The illustrated vertically-strung placement of components has been found to work well in the cupped contours of a typical backrest, although other placements are possible, and will depend somewhat on the contours of the backrest 114 and the desired massage and heat placement points on the patient's back.

[0027] FIG. 5 shows the outer, patient-facing layers of backrest 114 partly removed to display the components underlying the positional schematic of FIG. 4 and the manner in which they are mounted in the backrest. Massage motors 116 are of the type found in commercially available massage pads and cushions, nested in correspondingly-shaped cutouts 114d formed in the thick foam core 114c of backrest 114. Each motor is supplied with electric power through conventional wiring 115, and operates in on/off modes and optionally at different massage levels, for example by adjusting the speed of the motor by regulating the power supplied through wiring 115 in known fashion. Control of the massage motors preferably rests with the patient, for example by incorporating on/off and speed controls in handheld remote 26 shown in FIG. 1A, or by using a separate remote control of the type often supplied with commercially available massage pads.

[0028] Nesting or embedding the massage units in a closely conforming fit in the foam of a cushioned portion of the heavy, stable dental chair tends to dampen excessive vibration, such that the massage received by the patient is gentle and relaxing and does not induce vibration in the patient that might interfere with the dental work.

[0029] Heat pad element 118 is likewise of the type found in commercially available massage pads and cushions, and may comprise an array of resistively-heated wire or wires 118a. The wire 118a may be secured to a pad or sheet of material 118b designed to face the patient and transfer the heat generated in an even, comfortable manner. Heat element 118 is essentially flat, so can be secured directly to the face of foam core 114c and/or to a thin overlayer 114b placed between backrest cover 114a and the components in core 114c. Overlayer 114b may be a thin extra layer, for example compressible foam, added to core 114c and conforming to the surface contour of the core, or may be a thin layer of core 114c cut away to act as a flap covering the massage components. Uniform, thin overlayer 114b cushions the massage units and distributes the massage more evenly over the backrest while maintaining the ergonomic surface contour of the backrest.

[0030] Heat pad element 118 can be turned on manually through a remote switch like that used for massage motors 116, or can be pressure-activated by a switch such as that shown at 119, also of the type found in commercially available massage pads and cushions. Illustrated switch 119 is shown nested in a cutout 114f, but with its upper surface preferably slightly above the surface of core 114c to ensure good contact with the patient's back through the cover 114a and foam overlayer 114b. Switch 119 is also shown with an extra piece of foam 119e between the upper surface of the switch unit and overlayer 114b to further improve switch-activating pressure from the patient's back without decreasing patient comfort.

[0031] FIGS. 5A-5C further illustrate the layered arrangement of massage components and backrest layers, and details of massage motors 116 and pressure switch 119. The thickness of the motors 116 is preferably less than or equal to the thickness of backrest foam core 114c. The motors are for example eccentric motors which when rotated cause their housings to vibrate at the desired massage frequency and amplitude. The illustrated pressure switch 119 is a simple set of leaf contacts 119a secured to an insulative plate 119b, with their contact ends spaced vertically and with the uppermost contact end forced into circuit-closing contact with the lower contact end when a patient leans back against the backrest. Foam spacers 119c and foam-covered “pressure plate” 119d serve to cushion and insulate the metal contacts from the backrest cover and the patient's back.

[0032] It will again be understood that the particular set of massage components described above, and their particular arrangement in backrest 114, can vary without departing from the scope of the invention as set forth in the following claims, and will be apparent to those skilled in the art now that I have set forth the foregoing example. It will also be understood that the invention can be applied to different styles of dental chair, and to different cushioned portions of a dental chair, although it is probably not desirable to build a massage function into the headrest portion as it may transmit too much vibration to the patient's mouth as the dentist is working. The degree and amount of massage, the specific mechanisms by which it is applied through the cushioning of the dental chair, and other variables can be selected on an individual basis according to preference, so long as they do not interfere with the dental work being performed on the patient. I accordingly claim: