Headrest support and adjustment mechanism

[0001] This invention relates to mechanism for adjustably supporting a headrest relative to a chair back.

[0002] In many situations, and particularly in medical and dental chair situations, chairs are provided with a back and a headrest which projects above the back. Attempts have been made to produce a comfortable and easily adjusted headrest, but for the most part these have not provided the range of adjustability and ease of use that may be desired.

[0003] The headrest often is a somewhat pillow-shaped element spaced from the upper edge of the chair back and needs to be positioned to comfortably cradle the user's head. The comfort and adaptability of the headrest will be determined in great part by its angular position relative to the chair back, its position relative to the plane of the support surface of the chair back, and its distance from the top of the chair back. Each of these may require different positioning due to the characteristics of the user.

[0004] Many conventional headrests on chairs, such as dental chairs, are mounted on the chair back through mechanism which provides some degree of adjustability. However, the adjustment may require loosening of a screw-actuated mechanism, adjusting the headrest, and then having to screw the mechanism back to a tightened condition. This often is a two-handed operation and requires more operator time and effort than is desired.

[0005] A more desirable mechanism would allow the headrest to be locked in a desired position with the mechanism at rest, be able to be released by a single-hand actuation, with release of the actuator then returning the mechanism to a lock-up condition.

[0006] Further, for matters of hygiene, a plastic bag, or other covering, often is placed over the headrest and actuator mechanism making it difficult to access screw actuators or other conventional adjustment mechanism. Thus, a mechanism which permits one-handed adjustment and which may be easily operated through such a covering would be desirable.

[0007] Further, it is desirable to have a headrest support and adjustment mechanism which permits at least two degrees of pivotal freedom. Such would allow the mechanism to be pivoted, or rotated, fore-and-aft relative to the chair back, and then have another adjustment permitting pivoting of the headrest itself relative to remainder portions of the mechanism.

[0008] In the past, the height adjustment of the headrest above the chair back generally has been permitted only through a major operating stem which is slidable relative to the chair back and then frictionally held in position. There has been little opportunity for minor adjustment of the height of the headrest once the stem is held in place. A need is apparent for some auxiliary slide mechanism allowing simple raising and lowering of the headrest relative to the chair back which may be accomplished either by the operator or the patient/user of the chair.

[0009] Additionally, it has been found that many headrests and headrest adjustment mechanisms are so thick, when measured front-to-back, that when the chair, headrest and patient are laid back to a nearly horizontal position, with the patient's head preferably as close to the operator's (dentist or hygienist) lap as possible, the patient's head still is elevated some distance above the operator's lap. This can produce an inconvenient working position for the operator, requiring that their hands and wrists be placed in undesirable positions. It has been found that the lower the patient's head may be relative to the operator's lap, the more desirable the angle for the operator's hands and wrists. Thus, a thinner mechanism and headrest are desirable to allow such.

[0010] Thus it is desirable to provide headrest adjustment mechanism which can be worked through a covering bag, is easy to clean, is simple to operate, is reduced to as small a package as possible to provide good positioning of the patient for the operator to work on, and is operated with a single hand operated manual actuator which requires a minimal amount of force to release the headrest from a lock up position to permit adjustment, yet when the actuator is released positive locking for the headrest in a desired orientation is provided.

[0011] The present invention is structured and operates to overcome many of the disadvantages set out above found in previous devices and to provide the desired characteristics described.

[0012] More specifically, mechanism is provided having an elongate mounting body with brackets pivotally connected adjacent its opposite ends for mounting to a headrest and to a chair back, with a plurality of elongate interleaved plate members, or fingers, pivotally connected to the brackets with a clamp-style locking mechanism releasably holding the interleaved fingers in frictional locked positions to secure the brackets in selected positions. Release mechanism is provided for temporarily releasing the clamping force to permit pivotal movement of the brackets relative to the mounting body to permit adjustment of the headrest relative to the chair back.

[0013] In one embodiment of the mechanism, a mounting body is a substantially enclosed housing and two sets of plate members, or friction plates, extend longitudinally of the housing with interleaved portions of the two sets of plate members situated within the enclosure. The plate members extend and move longitudinally of the housing. This provides a relatively thin assembly which permits a patient's head supported by the chair back and headrest to be positioned closely adjacent an operator's lap during use.

[0014] In the mechanism, a release mechanism operator in one embodiment includes an elongate lever pivotally mounted to provide adequate mechanical advantage for release of clamping force on the friction plates through one-handed use. This permits a user to easily release the locking mechanism holding the pivotal brackets in place to permit adjustment, and then release of the lever allows locking to recur.

[0015] Another aspect is the provision of a slide mechanism adapted to mount the headrest on the adjustment assembly, such that the headrest may be moved in a translational path toward and away from the back of the chair. This permits comfortable placement of the headrest for both tall and short patients.

[0016] The structure of the headrest support is such that the translational movement is accomplished in a sliding fashion by either the operator or patient to permit convenient and comfortable positioning of the headrest relative to the pivotal adjustment mechanism and the backrest.

[0017] In one embodiment slide mechanism mounts the headrest for translational movement relative to ancillary headrest support mechanism, such that the headrest may be moved to a position in which majority of the headrest extends beyond the ancillary support mechanism. In this position only the thickness of the headrest cushion and slide mechanism separate the patient's head from the operator's lap to permit optimum working position.

[0018] These and other features will become more apparent as the following description is read in conjunction with the drawings.

[0024] Referring to the drawings, and first more specifically to FIG. 1, at 10 as indicated generally a headrest with a cushion 11 supported above a chair back 12 such as would be used in a dental or other medical style chair to support a patient. The headrest is supported above the chair back 12 by adjustment and support mechanism indicated generally at 14 constructed according to an embodiment of the invention.

[0025] An elongate slide post, or bar, 18 would be attached to the back of chair 12 by a frictional holding mechanism which allows major raising and lowering of the headrest mechanism. This allows approximate positioning of the headrest but is inconvenient for finer adjustment once the patient is in the chair.

[0026] The adjustment and support mechanism 14 for the headrest according to the invention includes an elongate housing, or mounting body, 22. Referring to FIGS. 3-5, the housing has a selected length L, a selected height H, and a selected width W which are best adapted to provide the operational advantages of the present device. For example, the width W is greater than height H so that appropriate operating mechanism may be accommodated within the housing while still providing a low profile height H to allow patient's head on the headrest to be placed as close to the operator's lap as possible. The support mechanism 14 is show in FIGS. 3-5 in a substantially horizontal orientation which it may assume when a patient is laid back in the chair.

[0027] The housing 22 has a substantially planar top wall 24, a substantially planar bottom wall 26, spaced therefrom, and a pair of opposed spaced apart side walls 28,30. The top, bottom and side walls define an enclosure which houses the major portion of the operating components of the apparatus.

[0028] A headrest mounting bracket 34 having a pair of bracket arms 34a, 34b is pivotally connected through pivot connection, or rod, 36 adjacent one end of housing, or body, 22. Pivot connection 36 is spaced outwardly from a central region of housing 22 toward said one end. Pivot connection 36 has an axis 36a which extends laterally, or widthwise, of housing 22. Headrest bracket 34 also has a lever arm portion 34c thereon which extends laterally from pivot connection 36.

[0029] A crossplate, or guide plate, 38 extends across outer edge portions of bracket arms 34a, 34b and is secured, as by welding, thereto or is cast as a single element with bracket arms 34a, 34b. The crossplate has opposed outer edge, or margin, portions 38a,38b which project laterally outwardly beyond bracket arms 34a,34b and a central portion 38C as best seen in FIGS. 2 and 5.

[0030] As best seen in FIG. 2, cushion 11 of headrest 10 may have a shallow curved configuration to comfortably cradle a patient's head, indicated generally at 40 in dashed line in FIG. 2. A connector plate, or member, 44 may be secured to the back of cushion 11 and, as best seen in FIG. 2, and has a shallow curved configuration which conforms to, or is complementary to, the curved configuration of cushion 11. Connector plate 44 has laterally spaced apart parallel guide rail portions 46,48 extending longitudinally of the connector plate and forming channels, or guideways, 46a, 48b adapted to slidably receive edge margin portions 38a, 38b, respectively, of crossplate 38 therein. Channels 46a, 48b act as guideways to mount connector plate 44 on headrest bracket 34 and permit translational sliding movement relative thereto. Explaining further, a sliding fit is provided between edge margins 38a, 38b and channels 46a, 48b permitting the headrest connector plate 44 and the headrest cushion connected thereto to be slid along crossplate 38 toward and away from chair back 12.

[0031] To improve the operation of this translational sliding movement, appropriate materials may be interposed between edge margin portions 38a,38b and channels 46a,48a to provide a selected sliding fit therebetween. The fit should be such that an operator or patient may easily slide the headrest up or down to produce the most convenient or comfortable position desired. A layer of a material such as DELRIN (produced by EI Dupont De Nemours) has been found to work well as an interface in the channels between edge margin portions 38a,38b and channels 46a,48a. This, or other material appropriate to provide the desired sliding fit, may be applied either to edge margin portions 38a,38b or to the interiors of channels 46a,48a.

[0032] Referring still to FIG. 2, a cavity 42 is formed in central section 38c of crossplate 38 facing toward connector plate 44. A friction plate 47, which may be in the form of a block of NYLATRON (produced by Polymer Corporation) is situated in cavity 42 with a spring 49 biasing it outwardly toward connector plate 44. The biasing force of spring 49 urging friction plate 47 outwardly and against connector plate 44 serves to produce a selected frictional holding of the connector plate relative to the crossplate such that the headrest cushion will be held in a selected position once it is placed as desired by the user.

[0033] A back support bracket 50 to which post 18 is secured, as by welding or other means, is pivotally connected to housing 22 through a pivot connection, or rod, 52 adjacent the end of housing 22 opposite bracket 34. Pivot connection 52 is spaced outwardly from a central region of housing 22 toward said opposite end. The pivot connection 52 has an axis 52a which extends laterally, or widthwise, of housing 22.

[0034] Bracket 50 includes a pair of laterally spaced bracket arms 50a,50b. Bracket arms 50a,50b project outwardly from their associated end of housing 22 through openings defined in housing 22, as do bracket arms 34c,34b, at the opposite end of the housing. Bracket 50 has a lever arm portion indicated generally at 50c which projects laterally of pivot connection 52.

[0035] A plurality of elongate substantially planar parallel plate members, or fingers, also referred to herein as friction plates, 56 are disposed in a set. They are pivotally connected adjacent their outer set of ends at a pivot connection 58, or rod, 58 to lever arm 34c of bracket 34. The axis 58a of the pivot connection extends transversely, or widthwise, of housing 22. Remainder portions of plate members 56 extend longitudinally through a major portion of the interior of the enclosure provided by housing 22 toward the opposite end of the housing.

[0036] Elongate slots 56a are formed in plates 56 extending longitudinally thereof. These slots extend toward the opposite, or inner, ends of plates 56 spaced from the end portion connected to pivot connection 58. Plate members 56 and their respective slots 56a are aligned transversely, or widthwise, of housing 22.

[0037] A plurality of elongate parallel substantially planar plate members, or fingers, also referred to as friction plates, 62 are disposed in a set with their outer ends pivotally connected at a pivot connection, or rod, 64 extending transversely, or widthwise, of housing 22. The axis 64a of pivot connection 64 extends transversely, or widthwise, of housing 22. Plates 62 are connected to lever arm 50c in a region spaced from pivot connection 52 for bracket 50.

[0038] Remainder portions of plate members 62 extend longitudinally through the enclosure of housing 22 toward the end occupied by bracket 34. Plate members 62 have elongate longitudinally extending slots 62a formed therein which extend to a region adjacent their inner ends. Plate members 62 and their respective slots 62a are aligned transversely, or widthwise, of housing 22.

[0039] As best seen in FIG. 5, the inner end portions of the sets of plate members, fingers, 56 and 62 are interleaved in a mid-region of housing 22.

[0040] In the interleaved region portions of slots 56a,62a are aligned. An elongate rod portion 68 of a locking, or clamping, mechanism indicated generally at 70, extends laterally and slidably through aligned portions of slots 56a,62a. Rod portion 68 assists in maintaining alignment of the plate members as they move within the housing. Rod 68 has an enlarged cylindrical head portion 68a received in a cavity 72 formed in side wall 28. The opposite end portion 68b of rod 68 extends into a throughbore 74 in side wall 30.

[0041] An enlarged bearing member, or portion, 76 secured to rod 68 is mounted for reciprocating movement in the direction of arrow 78 and is positioned to bear against a laterally outwardly facing side of one of the plate members. In FIG. 5, it bears against an outer facing surface of a plate member 56. Rod 68 and member 76 are held against movement longitudinally of housing 22.

[0042] A plurality of stacked spring washers, or Bellville springs, indicated generally at 80 are interposed between side wall 28 of the housing and bearing member 76. These urge the bearing member away from wall 28 and into forceful bearing contact with the plate members. This forces the interleaved portions of the plate members into clamping engagement between bearing member 76 and the inner, or abutment, surface 30a of side wall 30. The forceful clamping of bearing member 76 against the interleaved portions of fingers 56,62 clamps them into frictional locking engagement such that they are held in the position shown. Since the outer end portions of the plate members 56,62 are connected to bracket members 34,50, this frictional locking will hold the brackets in their given positions, thus holding the adjustment mechanism in position relative to slide bar support 18 and holding headrest 10 in selected angular position relative to housing 22.

[0043] Release mechanism including a lever 84 is provided to release the frictional clamping force and allow the plate members, or fingers, to move longitudinally relative to the housing and relative to each other to permit rotation of and changing of the angularity of brackets 34 and 50 relative to housing 22.

[0044] The elongate lever 84 is pivotally connected at 86 to housing 22 and has an engaging projection 88 thereon closely adjacent pivot connection 86. When the lever is in the position illustrated in solid outline in FIG. 5, it has substantially no effect on the clamping mechanism and thus the clamping mechanism frictionally locks the plate members in position. Swinging of the lever member to the dashed outline position illustrated in FIG. 5, causes projection 88 to engage end portion 68b of rod 68 and force the rod and bearing member 76 away from clamping engagement with the plate members against the biasing force of springs 80. When the clamping force is thus released by swinging movement of the lever, the plate members are released allowing relative sliding movement therebetween. This permits rotational swinging of bracket 34 and bracket 50 relative to housing 22 to change the angular position of headrest 10. Release of lever 84 returns the mechanism to its locked up position.

[0045] The range of pivotal movement of brackets 34,50 and the commensurate longitudinal shifting of their associated fingers 56,62, respectively, are illustrated in FIGS. 3 and 4.

[0046] Explaining operation of the apparatus, the operator initially places headrest slide support, or rod, 18 in a selected position relative to the back rest. When a patient, or user, enters the chair, the operator may depress lever 84 easily with one-handed operation due to its significant mechanical advantage provided by the long lever arm to release the clamping lock of the fingers. With the clamping lock thus released, the angular positions of portions of the assembly may be easily adjusted to conform to the patient. Release of the lever returns the mechanism to a locked position.

[0047] When the user, or patient, is seated in the chair their back rests against the plane of the user-engaging surface of the chair back. When the clamping mechanism is released, housing 22 may be swung rearwardly or forwardly about its pivot axis 52 to swing the headrest relative to the plane of the user-engaging surface of the chair back. At the same time, the angle of head rest support bracket 34 may be swung about its pivot axis 36 to a selected angular position relative to housing 22. This is all permitted by longitudinal movement of plate members 56,62 within the housing when the clamping mechanism is released. In this way, the headrest may be positioned as desired for the most comfortable disposition for the user and convenient positioning for the operator.

[0048] Similarly, once the patient is situated, the slide mechanism connected to the back of the headrest allows the headrest to be easily slid up and down relative to the chair back to obtain desired vertical positioning.

[0049] The configuration of housing 22 and the operating mechanism mounted therein for permitting adjustment of the headrest and locking such in a selected position, has a relatively thin profile, or height H, allowing the patient's head to be placed closely adjacent the operator's lap. Further, the enclosed housing provides a protective casing for the operating mechanism which permits ease of operation, cleaning, and positioning.

[0050] While a preferred embodiment has been described herein, it should be apparent to those skilled in the art that variations and modifications are possible without departing from the spirit of the invention.