WO1995010961A1

WO1995010961A1 - Double articulated headrest for dental patient chair

Info

Publication number: WO1995010961A1
Application number: PCT/US1994/011418
Authority: WO
Inventors: John W. Lewis
Original assignee: Mdt Corporation
Priority date: 1993-10-21
Filing date: 1994-10-07
Publication date: 1995-04-27
Also published as: MXPA94008201A; AU8014194A

Abstract

A double articulated headrest (30) for dental patient chairs (10) includes a mounting mechanism with a headrest support rod (46) extending through one end of a central clamping member (50), a chair connector rod (74) extending through another end of the central clamping member and locking means (110) operable with one hand to compress elements of the central clamping member (50) such that they simultaneously releasably clamp the chair connector rod (74) and the headrest support rod (46) with respect to the central clamping member.

Description

DOUBLE ARTICULATED HEADREST FOR DENTAL PATIENT CHAIR

BACKGROUND OF THE INVENTION Field: This invention relates to the adjustable headrests of chairs used for the provision of professional services in the vicinity of a person's head. It is particularly directed to mounting systems for such headrests, notably those of patient chairs, such as those used in dental practice.

State of the Art: Dental patient chairs have often included a headrest that can be tilted with respect to a chair back. This feature provides better patient comfort while a dentist is performing dental operations. The adjustable headrests previously known have required that both hands of an operator be used to make one or more adjustments. This procedure is cumbersome if the operator happens to be holding a dental tool or is otherwise involved in a dental procedure at the time it becomes desirable to make a headrest adjustment. Moreover, the specific positionings achievable with available adjustable headrests are limited. Tilting adjustments are typically provided by a mechanism coupled to a headrest support which independently slides into and out of corresponding support structure formed as part of the patient chair back.

Certain dental patient chair arrangements provide an axis about which a headrest tilts and another axis about which a support interconnecting the back of the patient chair and the headrest rotates. A lever arrangement is operated to move and lock both the headrest and the support. The location of the lever is such that two hands are required to operate the lever while also manipulating the headrest. Trial and error is typically required to set the headrest at an optimum position. The headrests associated with other chairs used in physical therapy, medical, personal grooming and other professions to position a person's head appropriately for the provision of professional services have similar concerns and limitations.

There remains a need for a headrest for a professional services chair, notably a dental patient chair, the positioning of which can be easily and quickly adjusted by an operator using only one hand. Such a headrest should be adjustable with respect to the distance the headrest is positioned away from the top of the chair back; the position of the headrest, forward or back, with respect to the chair back; and the tilt angle of the headrest relative to the chair back.

SUMMARY OF THE INVENTION The present invention provides a headrest, including a mounting mechanism, adaptable for use with professional services chairs. Although the headrest of this invention finds application in a variety of professional surroundings, it is for convenience described in this disclosure with particular reference to dental patient chairs. The mounting mechanism of this invention allows double articulated pivoting of the headrest with respect to the back of the chair on which it is installed. Further, the double articulated mounting mechanism can be easily operated with one hand.

A double articulated headrest of this invention includes a mounting mechanism with a headrest support structure extending through one end of a central clamping member, a chair connector structure extending through another end of the central clamping member and locking means operable with one hand to compress elements of the central clamping member such that they simultaneously releasably clamp the chair connector structure and the headrest support structure with respect to the central clamping member. The mounting mechanism generally comprises a central member with a first segment constructed and arranged to couple with a headrest support structure and a second segment constructed and arranged to couple with a chair connector structure. A headrest support structure is connected to the first segment through a first lockable articulating joint. A chair connector structure is connected to the second segment through a second articulating joint. Attachment means is provided for fixing the chair connector structure to a chair back. Suitable operation means is structurally associated with the central member, and is structured and arranged for simultaneously and releasably clamping the central member to both the chair connector structure and the headrest support structure. In this fashion, it is possible selectively to lock or unlock the first and second joints simultaneously with one hand. In a typical arrangement, the first and second segments of the clamping member are provided with first and second bores, respectively, comprising the first and second articulated joints. For example, each joint may comprise a cylindrical member rotatably positioned within one of the bores. These first and second bores may be interconnected by an approximately longitudinal channel through the central member to separate that member into a front structural element and a rear structural element. These elements cooperatively function as a clamping arrangement which simultaneously either lock or unlock the first and second articulated joints. In such assemblies, the operation means is manipulated to draw the front and rear elements towards each other in a clamping action which applies sufficient clamping force to lock the joints against further articulation. One of the front and rear elements may be divided into respective components of the first and second segments by a slot communicating with the channel.

The operation means is ideally structured so that it functions to apply clamping force simultaneously to the first and second segments in the vicinity of the slot. One suitable mechanism locates a third bore with its axis through the slot, approximately normal the two elements. The bore may extend completely through the front and rear elements. A locking bolt may be positioned through the third bore so that its head engages the outer surface of one of the elements. A locking nut threaded onto the locking bolt engages the outer surface of the other element. The bolt is turned within the nut to either increase or decrease clamping force at the joints.

In a specific embodiment, a central clamping member has a headrest support rod inserted through a first bore formed at one end and a chair connector rod through a second bore formed at an opposite end of the clamping member. The central clamping member is split to form separated front and rear elements, and the front element is transversely divided by a slot. A central aligned bore extends transverse to and is positioned midway between the first and second bores and through the spaced apart front and rear elements. A locking bolt extends through the central aligned bore of the central clamping member to be threaded into a locking nut so that turning of the locking bolt into the locking nut will compress the centrally split front element towards the rear element. This action clamps and locks the central clamping member to each of the headrest support rod and the chair connector rod. Conversely, turning of the locking bolt out of the locking nut will allow the split element to relax and to release the clamping action on the headrest support rod and chair connector rod so that they can rotate in the first and second bores, respectively, of the central clamping member.

THE DRAWINGS

In the drawings, which illustrate what is currently regarded as the best mode for carrying out the invention, FIG. 1 is a perspective view of a dental patient chair having a headrest of the invention mounted to the chair back;

FIG. 2 is an enlarged, fragmentary view showing in front elevation the major components of the central clamping member of FIG. 1, partially cut away for clarity; FIG. 3 is a view in vertical section through the central clamping member, taken on the line 3-3 of FIG. 2;

FIG. 3 A is an enlarged sectional view taken within the line 3A-3A of FIG. 3; and

FIG. 4 is a rear elevation view of the central clamping member of FIG. 2.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT A dental patient chair, shown generally at 10 in FIG. 1, includes a pedestal base 12, a chair support 14, a chair seat 16 and a chair back 18. Arms 20 are provided at opposite sides of the chair back, and project from the chair back alongside and above a portion of the chair seat 16.

A headrest, designated generally 30, is adjustably connected to an upper end 32 of the chair back 18. The headrest includes a padded cushion 34 secured to a backing plate 36. The backing plate 36 has spaced arms 38 and 40 that terminate in sleeves 42 and 44 (FIG. 2). A headrest support rod 46 is positioned through the sleeves 42 and 44 so that it is joumaled through a first bore 48 of a central clamping member, designated generally 50. Screws 52 and 54, which may be flat head screws but are illustrated as set screws, are passed through the sleeves 42 and 44 are threaded into the rod 46, thereby to lock the headrest assembly 30, including the padded and shaped cushion 34, backing plate 36, spaced arms 38 and 40 and sleeves 42 and 44, directly to the rod 46, and thus to the clamping member 50. The central clamping member 50 defines a second bore 58 extending approximately parallel the first bore 48 and at an end 60 opposite the end 62 of the central clamping member containing the support rod 46. The central clamping member 50 is split by a channel 64 (FIG. 3) between the bores 48 and 58 to define a front element 66 and a rear element 68, respectively. The channel 64 is shown disposed approximately parallel the axes of the bores 48 and 58. Front element 66 is divided intermediate its length by a slot 70 (FIG. 2), transverse the channel 64, into a first segment 66 A and a second segment 66B.

A chair connector rod 74 is journaled through the second bore 58, and is positioned through sleeves 76 and 78, respectively, fixed to spaced apart arms 80 and 82 of a slide plate 84. The plate 84 slides snugly into a pocket 86 formed in the upper end 32 of the chair back 18. Screws 88 and 90, respectively, passed through the sleeves 76 and 78 and threaded into the chair connector rod 74, securely lock the arms 80 and 82 directly to the chair connector rod, and thus to the clamping member 50. A third bore 100 (FIG. 3) is provided through the front element 66, between its segments 66A, 66B, and the back element 68. The axis of the bore 100 is positioned within the slot 70. An enlarged counterbore 102 is provided in the element 66 and an even larger counterbore 104 is provided at the opposite end of bore 100 in the element 68. As illustrated by FIG. 3, a shoulder 106 projects from the head 108 of a locking bolt 110 shown installed through the bore 100 to engage a locking nut 112. The bolt 110 and nut 112 are preferably left hand threaded so that clockwise rotation of the bolt effects tightening of the clamp 50. The locking nut 112 is positioned in the counterbore 104 in rear element 68, and as best shown by FIG. 4, includes six equally spaced projecting fingers 114, extending from a central area 115. The nut 112 is secured against rotation by a screw 116 turned into the bottom of counterbore 104 and positioned between adjacent fingers 114. As illustrated, a pair of threaded holes 118 are positioned selectively to receive the screw 116. These holes 118 are positioned such that as the locking nut 112 is threaded onto the locking bolt 110, one hole 118 is inevitably located beneath a finger 114 while the other is inevitably located between two other of the fingers 114. This positioning allows the locking nut 112 to be secured at selected thirty degree increments of rotation. This arrangement permits the nut to be tightened onto the locking bolt to achieve a desired compression of the front and rear elements 66 and 68 with a limited rotation of the bolt 110, thereby developing the clamping force needed to lock the headrest support rod 46 and chair connector rod 74 into the bores 48 and 58, respectively.

A needle bearing 120 is sandwiched between a pair of thrust bearings 122 (FIG. 3) and the bearings 120 and 122 are mounted in counterbore 102 on a shoulder 124. These bearings permit the bolt 110 to turn easily into and out of locking nut 112. Head 108 also includes an enlarged circular mid-portion configured as a knob 126 and an undersurface 128 positioned to act through bearings 120 and 122 to press upon shoulder 124 and the segments 66A, 66B of the front element 66 adjacent the counterbore 102. A pair of extensions 130 and 132 (FIG. 2) radiate outwardly from opposite sides of knob 126, and each such extension has a flat wing member 134 (FIGS. 1 and 4) projecting alongside the central clamping member 50 and parallel to the central aligned bore 100.

In use, the central clamping member 50 is secured to the top end 32 of a chair back 18, as by insertion of a plate 84 on the ends of the arms 80 and 82 into the chair back. The cushioned head rest 30 is attached to the central clamping member 50 with arms 38 and 40 fixed to the headrest support rod 46. Positioning of the headrest relative to the chair back is accomplished by loosening the central clamping member 50 through turning of the locking bolt 110 and pivoting of the central clamping member around the chair connector rod 74 and of the head rest 34 with the headrest support rod 46. The central clamping member 50 is released from clamping engagement with the headrest support rod 46 and with chair connector rod 74 by turning of the head 108 of locking bolt 110 to release the compression pressure applied to the front element 66 and rear element 68 of the central clamping member 50. From behind the chair 10, an operator may easily rotate the head 108 by pushing with a single digit of one hand down on one of the flat wing members 134. A few degrees of rotation is sufficient for this purpose. At the same time, the operator may grasp the central clamping member 50 to pivot it with respect to the chair connector rod 74. The fingers of the hand resting on the flat wing member 134 are inevitably appropriately positioned to manipulate the arms 38 and 40 as required to rotate the headrest with respect to support rod 46.

Once the central clamping member 50 and headrest 30 have been properly positioned, the operator, with the same hand, may rotate the head 108 to turn the bolt 110 into locking nut 112, thereby again compressing the elements 66 and 68 to apply clamping pressure to the chair connector rod 74 and the headrest support rod 46. Again, only a few degrees of rotation provides sufficient clamping force to lock the assembly against further movement. While the illustrated embodiment of the invention has been herein described, the appended claims are intended to encompass equivalent structures, without regard to the particular environment of use appropriate for various other specific embodiments.

Claims

THE CLAIMS What is claimed is:

1. A double articulated structure for mounting a headrest to a chair, comprising: a central member with a first segment constructed and arranged to couple with a headrest support structure and a second segment constructed and arranged to couple with a chair connector structure; a headrest support structure connected to said first segment through a first lockable articulating joint; a chair connector structure connected to said second segment through a second lockable articulating joint; attachment means for fixing said chair connector structure to a chair back; and operation means structurally associated with said central member, said operation means being structured and arranged for simultaneously and releasably clamping said central member to each of said chair connector structure and headrest support structure, whereby selectively to lock or unlock said first and second joints.

2. A double articulated structure according to Claim 1, wherein: said first and second segments are provided with first and second bores, respectively, comprising said first and second articulating joints.

3. A double articulated structure according to Claim 2, wherein: said first and second bores are interconnected by an approximately longitudinal channel through said central member to separate a front element from a rear element of said central member; and said operation means is operable to draw said front and rear elements towards each other in a clamping action, whereby to lock said first and second joints.

4. A double articulated structure according to Claim 3, wherein: one of said front and rear elements is divided into components of said first and second segments by a slot communicating with said channel; and said operation means functions to apply clamping force simultaneously to said first and second segments in the vicinity of said slot.

5. A double articulated structure according to Claim 4, further comprising: a third bore with its axis through said slot, said bore extending through said front and rear elements; wherein said operation means comprises a locking bolt extending through said third bore and a locking nut threaded onto said locking bolt.

6. A double articulated structure according to Claim 5, wherein: said third bore has enlarged first and second counterbores at the outer surfaces of said front and rear elements, respectively; said locking nut is positioned in one of said counterbores; said bolt includes a head having a shoulder projecting into the other of said counterbores; and structural projections extending from opposite sides of said head constitute means for turning said bolt by the application of hand pressure.

7. A double articulated structure according to Claim 6, further including: a plurality of needle bearings mounted in said third bore and in engagement with said bolt.

8. A double articulated headrest mount for dental patient chairs comprising: a central clamping member having a pair of parallel bores therethrough, said bores being respectively located at opposite ends of said central clamping member, said central clamping member including: front and rear elements spaced apart by a channel interconnecting said parallel bores; a slot through said front element and extending transverse to said channel; and a central bore hole through said front and rear elements, said channel and said slot; a locking bolt extending through said central bore with a head of said locking bolt engaging one of said elements of said clamping member; and a nut threaded onto said bolt to engage the other element of said clamping member.

9. A double articulated headrest mount according to Claim 8, further comprising: bearings mounted in said central bore to provide bearing surfaces for said locking bolt; and structural wing members extending as part of said locking bolt parallel to said central bore hole, whereby a user can rotate said bolt by pressing a single digit of one hand on a said wing member.

10. A double articulated headrest for patient chairs, comprising: a central clamping member having a pair of parallel bores therethrough at opposite ends thereof; a headrest support rod joumaled through one of said bores; a chair connector rod journaled through the other of said bores; a padded and shaped headrest fixed to said headrest support rod for rotation with said headrest support rod; means for fixing said chair connector rod to a chair back; and operation means for clamping said central clamping member to each of said chair connector rod and headrest support rod.

11. A double articulated headrest according to Claim 10, wherein: said bores are interconnected by a channel through said central clamping member to separate a front element from a rear element of said central clamping member; one of said front and rear elements is divided into first and second segments by a slot communicating with said channel; and said operation means is structured and arranged to apply clamping force simultaneously to said first and second segments in the vicinity of said slot.

12. A double articulated structure according to Claim 11, further comprising: a third bore with its axis through said slot, said bore extending through said front and rear elements; wherein said operation means comprises a locking bolt extending through said third bore and a locking nut threaded onto said locking bolt.

13. A double articulated structure according to Claim 12, wherein: said third bore has enlarged first and second counterbores at the outer surfaces of said front and rear elements, respectively; said locking nut is positioned in one of said counterbores; said bolt includes a head having a shoulder projecting into the other of said counterbores; and structural projections extending from opposite sides of said head constitute means for turning said bolt by the application of hand pressure.

14. A double articulated structure according to Claim 13, further including: a plurality of needle bearings mounted in said third bore and in operable engagement with said shoulder.

15. A double articulated structure according to Claim 14, further including structural means for stopping the rotation of said locking nut within said counterbore.