Abstract:
A patient procedures chair is provided with a system that permits ready interchangeability of patient headrests with ease of positioning and locking in position while at the same time guarding against inadvertent axial removal.

Description:
BACKGROUND OF THE INVENTION 
     Patient comfort and positioning are important goals of all medical procedure chairs. Additionally, particular medical specialties have requirements beyond these basic considerations. For example, dermatologists, plastic surgeons, oral maxillofacial surgeons and specialists practicing otolaryngology require maximum access to the head and neck area of patients. Other medical specialists, such as gynecologists, proctologists and podiatrists have different desired features in procedure chairs. Thus, for procedures involving the head and neck area of patients, it is preferable that the position of the headrest be adjustable and that the neck area be narrow. The specific configuration of the headrest itself should be variable to accommodate different types of procedures involving the head. It is desirable, therefore, that the headrest, on the one hand, be easily positionable and readily locked in a desired position, and on the other hand, that headrests of different sizes and shapes can be quickly and easily substituted to enhance the performance of different types of procedures. 
     SUMMARY OF THE INVENTION 
     A procedure chair in accordance with the present invention is ideally adapted for those procedures specifically directed to the head and neck areas of the patient. A narrow neck section permits easy adjustment of the headrest toward and away from the back section of the chair and the headrest itself is adjustable about multiple axes for convenience in positioning the patient in an optimal position. More importantly, the entire headrest may be quickly and easily removed and a headrest of a different configuration or size substituted and locked securely in place without the use of tools. A single, hand-operated knob permits the headrests to be interchanged and locked into position; thus providing a rigid interconnection between the headrest and back section of the chair. The hand-operated knob serves the dual function of providing easy substitution of headrests and also of simultaneously locking the headrest about its multiple axes of adjustability, all with a simple twist of the hand-operated knob. To prevent inadvertent axial removal of a headrest during its adjustment about its axes, the headrest is provided with a recess in its lower surface that receives the headrest connector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a procedure chair in accordance with the present invention; 
         FIG. 2  is a plan view of the seat back and headrest of the chair extended out in planar configuration; 
         FIG. 3  is a side view of that portion of the chair shown in  FIG. 2 ; 
         FIG. 4  is a perspective view of the upper portion of the back section and headrest of the chair; 
         FIG. 5  is a perspective view illustrating the manner of removing the headrest; 
         FIG. 6  is a cross-sectional view of the clamping mechanism associated with the headrest of the chair; 
         FIG. 7A  is a front perspective view of a headrest of a different size and shape than that shown in  FIGS. 1-4 ; 
         FIG. 7B  is a rear perspective view of the headrest of  FIG. 7A ; 
         FIG. 7C  is a side view of the headrest of  FIGS. 7A and 7B ; 
         FIG. 8A  is a front perspective view of still another size and shape headrest; and 
         FIG. 8B  is a rear perspective view of the headrest of  FIG. 8A . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  of the drawings shows a procedure chair  10  having a foot section  12 , a leg section  14 , a seat section  16 , a back section  18 , and a headrest  20 . The chair is mounted on a base  22 , which is capable of vertical movement to position a patient at an appropriate elevation. As best seen in  FIGS. 4 through 5  of the drawings, a pair of posts  24  are slidably received in bearings  26  mounted in the back section  18 . A clamping mechanism  27  is operable through a hand knob  28  to fix the posts  24  at their desired position with respect to the back of the chair  18 . Fixed to the distal ends  30  of the posts  24  is a crossbar  32 . The crossbar  32  is received in a socket  34  in one end of a connector  36  that is provided with a second parallel socket  38 . 
     The headrest  20  has a padded upper surface  40  and a lower surface  42 . A pintle  44  is fixed at one end  46  to the lower surface  42  of the headrest  20  and is cantilevered out over the lower surface  42 . This cantilevered construction provides a free end  47 , as best seen in  FIG. 5 , which is insertable into the socket  38  to permit selective attachment of headrests of various configurations. These may be as shown in  FIGS. 7A-7C  and  8 A and B. Each, it will be noted, includes a cantilevered pintle  44 ′ and  44 ″ having free ends  47 ′ and  47 ″ to be received in the socket  38  of the connector  36 . Also, it will be apparent that these are just a few of the wide variety of headrests of various sizes and shapes that are available. 
     The connector  36  engages both the crossbar  32  and pintle  44  in its sockets  34  and  38 , respectively. Twisting the knob  37  clamps the crossbar  32  and the pintle  44  simultaneously, to lock the headrest against movement about the two parallel axes defined by the crossbar  32  and the pintle  44  and form a rigid connection between the headrest and back section, with no play or “slop.” Thus, the headrest is both easily removed and replaced and easily adjusted about dual axes. 
     The clamping mechanism for the crossbar and pintle  32  and  48 , respectively, is best seen in  FIG. 6 . The crossbar  32 , pintle  44  and associated bearings  50  are received in a resilient clamp  52  having opposing, substantially C-shaped sections  54 . The clamp  52  has a threaded central socket  56 , which receives a threaded shaft  58 , to which is attached the knob  37 , as also seen in  FIGS. 4 and 5  of the drawings. 
     A spring washer  60  and suitable bearing assembly  62  are interposed to bear on the upper leaf sections  64  of clamp  52  as the threaded shaft  58  is turned by the knob  37 , causing the clamp to squeeze the bearings  50  and the pintle  44  and crossbar  32  received in the bearings and rigidly lock them in a desired position. 
     The same mechanism that permits the headrest  20  to be easily removed and replaced by another headrest also allows for adjustments of the position of the headrests about dual axes. As seen in  FIG. 5  of the drawings, upon turning the knob  37  the clamping force exerted against the crossbar  32  and the pintle  44  is relieved. The headrest may then be adjusted as desired. The clamp is once again tightened to lock the headrest rigidly to the back section. 
     It will also be noted that the headrests are provided with a recess, as best seen at  70  in  FIGS. 4 and 5 ,  70 ′ in  FIGS. 7B and 7C  and  70 ″ in  FIG. 8B . During adjustment of the headrests about the two axes, the connector  36  may be seated in the recess, as shown in  FIG. 7C , to prevent the headrests from being inadvertently removed axially. 
     While the present invention has been illustrated by the description of one or more exemplary embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.