Abstract:
A lift and tilt chair including both motorized lift capability and motorized tilting capability A hydraulic lift cylinder is provided and operates in conjunction with a motorized tilting system. A seat support is provided having rollers affixed thereto for providing the tilting motion and having the lift cylinder attached thereto for allowing raising and lowering of a patient seated within the chair.

Description:
This application is a continuation of Ser. No. 09/177,808 filed Oct. 23, 1998 now U.S. Pat. No. 6,106,065 which claims the benefit of U.S. Provisional Application No. 60/063,114 filed Oct. 24, 1997. 
    
    
     SUMMARY OF THE INVENTION 
     The present invention generally relates to medical chairs and, more specifically, to chairs that may be moved by a medical professional to place a patient in a desired position. 
     BACKGROUND OF THE INVENTION 
     Many different types of chairs have been developed in the medical field for placing patients in a desired position for treatment or diagnosis. These include dental chairs and ophthalmological chairs. One such chair is disclosed in U.S. Pat. No. 5,467,002, assigned to the assignee of the present invention, the disclosure of which is hereby fully incorporated by reference herein. The chair disclosed in this patent has the ability to raise and lower a patient seated within the chair and also the ability to recline the patient and raise the patient&#39;s feet by way of a pivoting backrest, leg rest and footrest. Often, it is desirable to simply tilt the patient back while leaving the patient in essentially the same seated position. Such chairs are typically referred to as “tilt chairs”. Various tilt chairs have been proposed in the past, however, no chair to date has adequately and efficiently allowed a medical professional to both tilt a patient into position and raise or lower the patient during or after diagnosis or treatment. 
     For these and other reasons, it would be desirable to provide a tilt chair which is cost efficient in design, yet may be used by a medical professional to both tilt a patient automatically into position and raise or lower that patient into the ultimately desired position. 
     SUMMARY OF THE INVENTION 
     To these ends, the present invention provides a medical chair having a patient support generally affixed to a base by a lifting and tilting mechanism. The lifting and tilting mechanism generally comprises a seat support having four rollers mounted thereon and contained within slots respectively contained in a pair of support rails affixed to the back of the patient support. A pair of rollers is mounted to the front of the seat support and a pair is mounted to the rear thereof. The slots are curved to define the tilting path of the chair. The lifting and tilting mechanism further includes a lifting cylinder rigidly affixed to the seat support between the front and rear pairs of rollers. This lifting cylinder is connected to a motorized hydraulic pump contained in the base of the chair. An actuator is affixed between the patient support and the seat support for moving the patient support relative to the seat support by movement of the rails along the front and rear pairs of rollers. Significantly, the front and rear pairs of rollers are mounted to the seat support in generally the same horizontal plane for stability, ease of manufacture and proper movement of the rollers within the guide slots. 
     It will be appreciated that the invention provides a chair that may have a single foot control for use by a medical professional to provide powered movement both in a tilting manner and a vertical direction to adjust the position of a patient undergoing diagnosis or treatment. The invention further provides such advantage in a cost efficient manner due to the integrated design of the lifting and tilting mechanism. Additional advantages and objects of the invention will become more readily apparent to those of ordinary skill upon review of the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a chair constructed in accordance with the invention, but having certain conventional items, such as the arm rests, removed for clarity; 
     FIG. 2 is a side elevational view similar to FIG. 1 but showing the chair n a tilted position; 
     FIG. 3 is a cross section view of the chair illustrated in FIG. 1 taken along line  3 — 3  thereof; and 
     FIG. 4 is a rear perspective view of the chair shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a chair  10  constructed in accordance with a preferred embodiment of this invention. Chair  10  generally comprises a patient support  12  affixed to a base  14  for both tilting and raising or lowering with respect thereto as will be described. Patient support  12  comprises cushions  16 ,  18 ,  20 ,  22  that are respectively attached to flat support members  24 ,  26 ,  28 ,  30 . 
     As shown in FIGS. 1 and 2, a lifting and tilting mechanism  40  generally connects patient support  12  to base  14 . Specifically, a lift cylinder  42  extends from base  14  and is operatively connected to a motorized hydraulic pump  44  as generally described in the above incorporated U.S. Pat. No. 5,467,002. Generally, such hydraulic cylinders are known in the art and take many forms. A suitable hydraulic lift mechanism is fully described in U.S. Pat. No. 5,461,965, assigned to the assignee of the present invention and hereby fully and expressly incorporated by reference herein. Cylinder  42  is attached to a seat support  46  by a nut  47 . As shown in FIGS. 1-3, front and rear pairs of rollers  48   a ,  48   b  are affixed for rotation relative to seat support  46 . As specifically shown in FIGS. 1 and 2, front and rear pairs of rollers  48   a ,  48   b  have two common axes that are each contained in generally the same horizontal plane. Rollers  48   a ,  48   b  are also connected for rolling movement along rails  50 ,  52 . Specifically, rollers  48   a ,  48   b  are contained within respective curved slots  54 ,  56  of rails  50 ,  52 . Slots  54 ,  56  are closed end slots and the ends thereof may define the limits of movement, respectively, of front and rear rollers  48   a ,  48   b.    
     As also shown in FIGS. 1 and 2, connector blocks  58  connect rails  50 ,  52  to respective seat support members  26 ,  28 ,  30 . Side supports  60  (only one shown in FIGS. 1 and 2) are also rigidly affixed to rails  50 ,  52  and connect a footrest  62  pivotally at the lower end thereof. A cover  64 , shown in phantom in FIGS. 1 and 2, may be used to conceal the various mechanical hardware of chair  10  at the rear. 
     Now referring to FIG. 4, the actuating mechanism for tilting the patient support  12  with respect to base  14  includes a threaded rod or drive screw  66  and a drive nut  72  attached via a pivot  68  mounted generally at the rear side of support member  30  and a motor  70  which may rotatably operate a worm drive (not shown) that is in meshed relation to threaded rod  66  in a conventional manner. Operation of motor  70  by conventional controls will cause rotation of the worm drive and rotation of threaded rod  66  within drive nut  72 . A reversible motor is used to allow rotation of threaded rod  66  in either direction. It will be appreciated that rotation of threaded rod  66  will cause drive nut  72  and therefore patent support  12  to travel up and down threaded rod  66  as rails  50 ,  52  move along the respective front and rear rollers  48   a ,  48   b  following curved slots  54 ,  56  along a purely arcuate path having a fixed center of rotation  80  as shown in FIG.  1 . 
     It will further be appreciated that conventional controls may be used operate motorized pump  44  and reversible motor  70  and that a foot switch box (not shown) may be provided with multiple switches for depression by the operator to respectively raise and lower the chair by operating motorized pump  44  and tilt patient support  12  by operation of motor  70 . The limits of travel for both the lifting and tilting operations may be controlled in conventional fashion. One preferred manner of controlling the tilting travel is to use a nut  72  that will continue to allow threaded rod  66  to rotate at the end of the travel. A timer may then be used in the control system to stop motor  70 . 
     While a preferred embodiment has been described, Applicant does not intent to be bound by the details associated with that preferred embodiment, but only by the scope of any claims ultimately granted in a patent.