US3661421A

US3661421A - Chair arm structure

Info

Publication number: US3661421A
Application number: US74308A
Authority: US
Inventors: Philip C Johnson
Original assignee: Dentsply International Inc
Current assignee: Dentsply Sirona Inc
Priority date: 1970-09-23
Filing date: 1970-09-23
Publication date: 1972-05-09
Anticipated expiration: 1989-05-09

Abstract

A support for chair arms pivoted to the back, respectively at one or both sides, for movement between a lower arm-supporting position and an elevated position to facilitate ingress and egress to and from the seat of the chair. The support includes link means operable in tension to support the arm in said lower position to minimize danger from accidental movement of the arm to a lower position and also provide desired clearance between said arm and chair seat without obstruction by said supporting link means.

Description

0 Umted States Patent 1151 3,661,2 1 Johnson 1 51 1y 9, 11972 [54] CHAIR ARM STRUCTURE 1,239,185 9/1917 Hunt ..297/417 X 1,737,947 12/1929 Rynearson ..5/1 14 [72] Invent Phi? cmcmnat" Ohm 2,689,600 9 1954 Van Briesen ..297/415 73 Assi nee: Dents 1 International Inc. York, Pa. 1 g p y FORElGN PATENTS OR APPLICATIONS [22] 1970 1,137,590 12/1968 Great Britain ..297/414 [21] Appl. No.: 74,308

Primary Examiner-Casmir A. Nunberg Related U.S. Application Data c, Remus Ju t [63] Continuation-impart of Ser. No. 863,085, Oct. 2,

1969, abandoned. [57] ABSTRACT A support for chair am1s pivoted to the back, respectively at [52] U.S. Cl ..297/417, 297/422 one or both sides, for movement between a lower arm-sup- [51] Int. Cl porting position and an elevated position to facilitate ingress [58] Field of Search ..5/82, 114, 119; 297/71, 162, and egress to and fr m he seat of the chair- The uppo t in- 297/347, 413-417, 420 Cludes link means operable in tension to support the arm in said lower position to minimize danger from accidental move [56] References Cited ment of the arm to a lower position and also provide desired clearance between said am and chair seat without obstruction UNITED STATES PATENTS y Said Supporting link means- 3,514,153 5/1970 Maurer et a1. ..297/71 13 Claims, 15 Drawing Figures PATEMTEUMAY 91912 3,661,421

SHEET 1 [1F 3 INVENTOR PHILIP C. JOHNSON PATENTEUHAY 91972 $661,421

SHEET 2 OF 3 INVENTOR PHILIP C. JOHNS ON BY v/ AT ORNEY PATENTEDMAY 9 I972 SHEET 3 BF 3 INVENTOR.

PHILIP C. JOHNSON 1 1 AT RNEY CHAIR ARM STRUCTURE This application is a continuation-in-part of my original application, Ser. No. 863,085, filed-Oct. 2, 1969, which is being formally abandoned upon the filing of the instant application.

BACKGROUND OF THE INVENTION The present invention primarily pertains to pivoted chair arms respectively adapted to be connected to one or both sides of the back of a chair essentially intended for medical purposes. The term medical purposes is intended to embrace especially chairs which are adapted to be used for various kinds of medical examinations and/or treatment of the types employed in ophtharnology; otolaryngology, which includes examination and treatment of the ear, nose and throat; dental examinationand treatment; and surgical examination and treatment.

It is common practice in chairs of the foregoing type to provide either at one or both sides thereof arms which, in normal .operation, extend substantially horizontally for purposes of the occupants of the chairs resting their arms upon the arms of thechair. However, to facilitate ingress and egress to and from said chairs, at least the more modern types thereof are arranged so that one or both of said arms may be elevated from a substantially horizontal position to a more or less vertical position along one side of the back so as to freely expose one side of the seat of the chair without obstruction from the arm.

Numerous types of medical chairs of the kinds referred to above presently are available and at least the more modern examples thereof are provided with arms which may be pivotally moved from a lower, substantially horizontal position to an inoperative upright or vertical position to eliminate any obstruction to the ingress or egress of a patient to or from the chair seat. Providing suitable bracing for such arms, however, particularly when disposed in the arm-supporting position, which is substantially horizontal, has presented many troublesome design and manufacturing problems. As a result, most of said arms are provided with an upstanding supporting post which extends between one side of the chair seat and the arm intermediately of the ends thereof, and especially near the outer end thereof.

Supporting post means of this type is satisfactory for purposes of affording adequate support per se. However, it presents problems with respect to the disposition of the post when the arm is to be raised to upright position, for example. If the post remains attached to the seat of the chair, it presents a serious obstruction to free access with respect to the seat thereof. If the supporting post is elevated with the arm when it is raised as aforesaid, repositioning'the supporting post with respect to an appropriate socket or receptacle on the chair seat usually is required.

Other attempts to solve the foregoing problem have resulted in the arm at one side of the chair being supported by a vertical post which is fixedly connected thereto intermediately of the ends of the arm and extends upwardly from one side of the seat of the chair, while the opposite arm is supported in pivoted, cantilever fashion by meansof a rotatable shaft arrangement which extends transversely through or across the back of the chair from the first-mentioned arm. Such arrangement includes locking or keying means which halt downward movement of the second arm in the desired substantially horizontal supporting position. The latter arrangement, however, includes a relatively lightweight arm which is not rigid and relies entirely upon movement-checkingmeans of very short radial dimension. Accordingly, especially if an attempt is made to lean or somewhat sit upon the arm, as is not uncommon, bending or actually shearing of the movement-checking mechanism and bending of the arms occurs.

SUMMARY OF THE INVENTION ported in the lower, arm-supporting position for the comfort of an occupant of the chair and said support means also provides for ready, manual elevation of the arm to a raised position without requiring disconnection or separation of any of the supporting mechanism, whereby upon return of the arm to the lower, arm-supporting position, the mechanism to support the arm in said position is restored automatically to its operative, supporting relationship with respect to the arm.

It is another object of the invention to provide chair armsupporting means which include linkage interconnected between the pivoted end of a chair arm and the seat of a chair in such manner with respect to the pivot of the arm that the linkage is placed under tension when force is applied downwardly upon the outer end of the arm when disposed in arm-supporting position, thereby affording maximum safety against accidental release of the arm from said position as under conditions when abnormal force is applied downwardly upon said arm.

It is a further object of the invention to provide said linkage means in the form of a plurality of pivotally connected links which, when the arm is raised to its elevated position, will both move rearwardly from the planes of the seat and back of the chair so as in no way to interfere with the ingress or egress to and from the chair seat.

It is still another object of the invention to arrange the pivotal connection of said linkage means to the arm and seat of the chair so that when the back of the chair is lowered from a normal, somewhat upright position toward a horizontal position, the angular relation between said arm and said back will be increased so as to continually dispose the arm at a comfortable position with respect to use thereof by the patient and, further, when the back of the chair is lowered toward said horizontal or reclining position, said arm also may be disposed closely along one side of the back, substantially within the plane thereof, if desired.

It is still a further object of the invention to provide an embodiment of linkage means for supporting the arms of chairs of the type referred to in which the linkage joint has latching mechanism which includes a spring-pressed detent and cooperating cam means which releasably holds the links in axial, operative alignment but the same may be moved to collapsed position simply by manual force applied laterally against the linkage joint.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an exemplary chair of the type to which the present invention is applicable and showing an arm at one side thereof held in an operative position by a chair arm support embodying the principles of the present invention.

FIG. 2 is a fragmentary side elevation of a portion of the chair shown in FIG. I, illustrated on a larger scale than employed in said figure, and showing details of the linkage means arranged to maintain the arm in the position shown in FIG. 1, the positioning means for said linkage means being elevated from its normal operative position to disclose details of the linkage means.

FIG. 3 is a fragmentary side elevation similar to FIG. 2 but showing the arm in raised position adjacent one side of the back of the chair and the linkage means being arranged in inoperative position to permit such disposition of the chair arm.

FIG. 4 is a fragmentary side elevation showing the relative positions of the chair seat and back when the back is disposed in reclining position, said view also illustrating the disposition of the arm with respect to the back when the linkage means remains in axially aligned position.

FIG. 5 is a fragmentary view similar to FIG. 4 but showing the arm disposed along the one side of the back and the linkage means being shown in the position assumed thereby under such circumstances.

FIG. 6 is a fragmentary side elevation showing portions of the seat and back of the chair otherwise shown in FIGS. 1 and 2 and illustrating, on a larger scale, details of the supporting and positioning mechanism for the back and arm of the chair when the back is disposed in upright position.

FIG. 7 is a fragmentary side elevation showing a portion of the chair details illustrated in FIG. 6 and the back being disposed in reclining position with the arm positioned along one side of the back.

FIG. 8 is an enlarged, fragmentary transverse sectional view showing the arm-supporting pivot means of the chair as seen on the line 8-8 ofFlG. 6.

FIG. 9 is a plan view, partly in horizontal section at one end, showing details of an alternative means for positioning the linkage in axially aligned manner.

FIG. 10 is a side elevation of the linkage per se shown in FIG. 9.

FIG. 11 is an enlarged side elevation, partly in longitudinal section, of another embodiment of linkage means from that shown in the preceding figures, as seen on line 11-11 of FIG. 12.

FIG. 12 is a side view of the embodiment of linkage means shown in FIG. 11.

FIG. 13 is a fragmentary view of the joint of the linkage means of FIGS. 11 and 12 when the links are angularly related to each other.

FIG. 14 is a fragmentary side elevation of a portion of a chair such as shown in FIG. 1, illustrated on a larger scale than in said figure, and showing the embodiment of linkage means shown in FIGS. 11-13 in arm-supporting position.

FIG. 15 is a view similar to FIG. 14 but showing the arm in raised position adjacent one side of the back of the chair.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a chair 10 is shown which is intended to be representative of a number of different types of chairs which, in general, can be classified as medical chairs. Chairs in this category are intended to be occupied by patients of various kinds of physicians, either for examination or treatment purposes. The patient sits upon the seat 12 and rests against the back 14. For purposes of both comfort and utility, chairs of this type usually are provided at opposite sides of the back with arms 16 upon which a patient may rest their arms. The seat is connected to a suitable chair base 17 which may be one of a wide variety of kinds, none of which comprise part of the present invention.

It is the principal objective of the present invention to provide either one or both sides of the back 14 of the chair 10 with arms 16 which are positioned so as normally to project forwardly from the front face of the back 14, whereby the same are substantially parallel to the upper surface of the seat 12. importantly, the arms 16 are spaced above the upper surface of the seat 12 so as to provide a substantially unobstructed space 18 between the arms 16 and the upper surface of seat 12, such clean space extending forwardly from the front surface of the back 14. Under certain conditions of use, it is essential and desirable that a patient sit sideways upon the chair. As readily can be appreciated from FIG. 1, by providing a space 18 of ample size between the seat 12 and arms 16, patients may move their legs from resting upon the forward portion 20 of the seat 12 to a position in which they extend downwardly from the side of the seat 12 and thereby occupy the space 18 between one of the arms 16 and said seat.

Especially for purposes of ingress and egress of a patient with respect to seat 12, it is preferred that at least one of the arms 16 be capable of being raised to an elevated position, such as shown in FIG. 3, for example. In such position, it extends closely along one side of the back 14 and thereby oflers no obstruction to the seating of a patient upon the seat 12, followed by swinging of the patients legs onto the forward portion '20 of the seat. After this, the arm 16 which has been raised to permit such ingress may be lowered to the operative, forwardly extending or substantially horizontal position shown in FIGS. 1,2 and 6.

For purposes of the present description of the invention, when the back 14 is in the position shown in FIGS. 1 and 2, for example, said back is referred to as being in the "upright" position, notwithstanding the fact that the upper end of the back actually extends a little greater distance rearwardly than the lower end thereof. Similarly, when the arm 16 is in the position shown in FIGS. 1, 2 and 6, it is referred to as being in the substantially horizontal" or arm-receiving position, notwithstanding the fact that it is not actually parallel to the supporting surface upon which the chair base 18 rests, for example. However, such position is regarded as being substantially horizontal.

In the preferred construction, the arm 16 preferably is approximately parallel to the upper surface of the seat 12, as indicated hereinabove. Also, although the present drawings illustrate only a single arm, it is to be understood that the arm rest shown therein could be duplicated on the opposite side of the chair and thereby provide a pair of arms respectively disposed at opposite sides of the back 14. In addition, the position of the arms 16 shown in FIGS. 1, 2 and 6 is considered to be the operative position, whereas when the arm is elevated to dispose the same substantially along one side of the back 14, it is considered to be in the inoperative position.

In the drawings comprising part of the present invention, for simplicity, the various figures illustrate only a single arm 16. It is preferred that the arm 16 and the mechanism which supports the same in accordance with the principles of the invention be disposed on the side of the back 14 which is the same side from which a patient normally gains ingress to the seat, said side also being that from which the patient normally makes egress therefrom. However, the structure of the present invention makes it possible to have both arms independently pivoted and supported as described so that a person may have ingress and egress from either side of the chair, thus increasing its versatility.

The present invention effects support of the arm 16 in both the operative position shown in FIGS. 1, 2 and 6, as well as the inoperative position shown in FIG. 3, for example, by linkage means 22 which is simple, yet highly effective to achieve the desired purposes. In the exemplary embodiment of the chair back 14 and arm 16, attention is directed to FIGS. 6 and 8 in which it will be seen that the chair arm essentially has an inner frame 24 which is substantially U-shaped in cross-section. One side 26 is apertured to receive a pivot bolt 27 therethrough. Said bolt also extends through a side frame member 28 of back 14. Suitable spacing washers 30 may be used between the adjacent side surfaces of the arm 16 and back 14, as shown in FIG. 8. Accordingly, the arm 16 is supported in cantilever manner and, as is best seen from FIG. 6, the pivot bolt 27 is closely adjacent the terminal end of the arm 16 which is pivoted to back 14.

In order to prevent downward movement of the outer end of arm 16 from the operative, lower supporting position thereof shown in FIGS. 1, 2 and 6, linkage means 22 is employed. The preferred manner of utilizing the linkage means is such that the application of weight upon the upper surface of arm 16, when exerted downwardly toward seat 12, places the linkage means 22 under tension, due to the arrangement of

pivots

27 and 56. The design of the linkage means thus has been purposely arranged in this manner so as to afford the safest manner of resisting, in particular, abnormal or excessive downward force applied against the am 16 such as when anyone leans heavily upon the arm or even attempts to sit upon it, as is not uncommon in actual use.

Details of the linkage means 22 are best shown in FIGS. 6 and 7, wherein it will be seen that a pair of

links

32 and 34 are pivotally connected at one end by a pivot pin 36. Said end of the link 32 is bifurcated to form a pair of wings 38 and the corresponding end of link 34 has a single tongue 40 which closely fits between the inner surfaces of the wings 38. Also, the outer end of tongue 40 is provided with a bevel 42 and a transversely extending terminal end surface 44, see FIG. 10, which abuts the inner end of the slot which defines the wings 38 when the

links

32 and 34 are disposed in axial alignment as shown in FIG. 10. Thus, the

links

32 and 34 can pivot with respect to each other only in one direction from axial alignment inasmuch as the engagement of the end surface 44 of tongue 40 with the inner end 46 of the slot between wings 38 will prevent relative movement between the links in one direction about the pivot pin 36 from said axially aligned positions thereof.

Positioning means for the

links

32 and 34 are provided in the form of a simple but effective sleeve 48. The operative position of the positioning sleeve 48 is as shown in FIGS. 1 and 4, wherein it surrounds and encloses the pivotally connected ends of the

links

32 and 34 and thereby makes the linkage means 22 rigid, with the individual links axially aligned. The operative position of the positioning sleeve 48 is maintained by the same abutting a fixed collar 50 on link 34. The positioning sleeve 48 is yieldably maintained in said position by a compression spring 52 disposed in a suitable slot in link 32, for example, as shown in FIG. 6. The pressure of said spring is exerted against a screw 54, or similar abutment means, in sleeve 48, as shown in FIG. 6. It will be understood that in FIG. 6, as well as in FIG. 2, the sleeve 48 has been retracted manually to a position in which the

links

32 and 34 may be pivotally moved with respect to each other.

When it is desired to pivotally move the arm 16 from the substantially horizontal, operative position thereof shown in FIGS. 1, 2 and 6, toward the inoperative position in which it is disposed along one side of the back 14, it is only necessary for the operator to manually move the positioning sleeve 48 from the position shown in FIGS. 1 and 4 to the exemplary position shown in FIGS. 2 and 6. In the latter position, the

links

32 and 34 may readily be moved to the position shown in FIG. 3, for example, thereby breaking the alignment of the linkage means. As soon as such breaking has been initiated, the sleeve 48 may be released and the spring 52 will move it against the pivotally connected end of the link 34, for example, as shown in FIGS. 3, 5 and 7.

One of the outstanding advantages of such arrangement is that when the arm 16 is to be restored to the operative position, by lowering it, for example, from the position shown in FIG. 3 to that shown in FIG. 2, such as after a patient has been disposed upon seat 12, the

links

32 and 34 will be pulled into alignment with each other. As soon as the tongue 40 is disposed fully between the wings 38 of link 32, the positioning sleeve 48 will instantly be moved by spring 52 against the top abutment 50, thereby surrounding the pivoted ends of the links and restoring the linkage means 22 to rigid, axially aligned condition. When in such position, it is stiff and capable of resisting substantial compressive forces if subjected thereto, such as, for example, when a patient is disposed in the chair when the back 14 is inclined toward the horizontal position, which is shown in exemplary manner in FIGS. 4, 5 and 7, for example, and the patient desires to attempt to pull himself upwardly toward a sitting position. Under such circumstances, the linkage means 22 are placed under compressive force but there is no danger of the same buckling, for example, so as to render the arm 16 capable of being moved backwardly toward one side of the back 14, due to the function of positioning sleeve 48.

The linkage means 22 controls the movement of the arm 16 due to one end of link 32 thereof being pivotally connected by a pin or bolt 56 between the sides of the U-shaped frame 24 of the arm, for example, outwardly from pivot bolt 27, as shown in FIG. 8. The outer end of link 34 of said linkage means is pivotally connected by a suitable pin 58 to a bracket 60 connected to one side of seat 12, as best shown in FIGS. 6 and 7. A hinge member 62 is connected to the adjacent side of back 14, as shown in FIG. 6, and is also pivotally connected to bracket 60 by a pivot pin 64.

By viewing FIG. 6, it will be seen that the pivotal axes of the pivot bolt 27 and pivot pin 56 which are connected to arm 16 are in a line which is substantially parallel to the line of axes of pivot pin 58 and pivot bolt 64. By such arrangement, when the linkage means 22 remains in axially aligned condition, and the back ,14 is tilted to reclining position, such as shown in FIG. 4, said linkage means and the various axes of the pivot means referred to will cause the arm 16 to be moved angularly with respect to the back 14, as shown in FIG. 4, so that an obtuse angle A is formed between the arm and the plane of the back 14. Said angle is greater than the angle which exists between the arm and back when the back is disposed in upright position as shown in FIGS. 1 and 2, for example. It has been found that this position of the arm 16 provides substantial comfort to an occupant by affording means to rest their arms upon the same.

More importantly, when the linkage means 22 is disposed in the position shown in FIG. 4, for example, substantial pulling force may be exerted by an occupant against the outer ends of the arms 16 to permit occupants to pull themselves toward a sitting posture and thereby facilitate the restoration of the back 14 to an upright position by any appropriate power means such as the exemplary elevating unit 66 which is at least partially shown in FIGS. 1 and 7, or by the back being manually moved by an operator or attendant.

In the event the arm 16 is initially disposed in upright position, adjacent one side of the back 14, it also is possible to lower the back 14 to a reclined position without disturbing the arm 16 or the linkage means 22. This can be appreciated by comparing FIGS. 3 and 5 in which it will be seen that the angle between the

links

32 and 34 is of greater extent in FIG. 3 than it is in FIG. 5. However, in both situations, the links extend rearwardly from the plane of the forward surface of the back 14 and thus in no way interfere with an occupant while seated in seat 12 and leaning against back 14, regardless of whether the back is in the upright or reclined position.

In view of the fact that the principal function of the linkage means 22, especially when in axially aligned condition, is to maintain the arm 16 in the lower, arm-supporting position, as shown in FIGS. 1, 2 and 6, in which position the linkage means is under tension, other means than the positioning sleeve 48 may be employed to retain the pivotally connected

links

32 and 34 in such axially aligned position. One such additional means is illustrated in FIG. 8 in the form of a coiled spring 68 which extends around the pivot pin 58 of link 34. Opposite ends thereof respectively are disposed within holes 70 respectively formed in link 34 and the inner wall of the slot in bracket 60 which receives the pivoted end of link 34, as clearly shown in FIG. 9. The coils of the spring 68 are disposed in such manner that the spring normally tends to urge the link 34 clockwise, for example, as viewed in FIG. 10. When urged in such direction, the engagement of end surface 44 of link 34 against the inner end 46 of the slot in link 32 will prevent any further pivotal movement in that direction between

links

32 and 34 after axial relationship has been established. Thus, the spring 68 constitutes a further embodiment of positioning means to maintain the

links

32 and 34 in axial relationship, over and above the positioning function of the sleeve 44 in the embodiment described hercinabove.

In addition to the embodiment of the invention illustrated in FIGS. 9 and 10 for purposes of maintaining the linkage in axially aligned, arm-supporting position, the present invention includes still another embodiment of linkage mechanism for said purpose which is illustrated in FIGS. 11-15. Referring to FIGS. 11-13, in particular, said additional linkage comprises a pair of

links

72 and 74 which preferably are cylindrical in shape but may be of other geometric configurations in crosssection, if desired.

The outer ends of the

links

72 and 74 are each provided with pivot holes 76 by which the opposite ends of the

connected links

72 and 74 are pivotally attached respectively to the pivot pin 56, which is connected to the rearward end of arm 16, for example, and pivot pin 58, which is supported by the brackets 60, as shown in FIG. 6. It is to be understood that, in regard to the embodiment of the linkage shown in FIGS. 11-15, the same is connectable to the chair structure illustrated in the preceding embodiment, and especially FIGS. l-8, as a substitute for the previously described linkage embodiments of the invention.

The ends of the

links

72 and 74 which are opposite those that contain the pivot holes 76 are shaped so as to interfit in a manner to form a connecting hinge structure. Specifically, but without limitation thereto, the link 72 is provided with a slot 78 which is best shown in FIG. 12 and extends inward from said end of said link a predetermined distance. The corresponding end of link 74 is shaped to provide a tongue 80, which is dimensioned to closely fit within the slot 78 for slidable, pivotal movement relative to the surfaces defining the sides of slot 78.

The interfitting tongue 80 and the portions of the link 72 which define slot 78 are transversely intersected by a plurality of coaxially aligned holes to receive pivot pin 82 which, specifically, is illustrated as a screw. An appropriate lock washer, not shown, may be utilized, if desired, with respect to said screw, and said screw preferably is threaded into at least one of the portions of the link 72 which defines the slot 78.

The pivotally connected

links

72 and 74 are maintained in the longitudinally aligned, normal operative position thereof, by latch means having the following preferred construction. Link 72, for example, is provided with a bore 84 which extends longitudinally thereinto from the base of slot 78. The bore 84 has an enlarged outer end 86. The bore 84 receives a compression spring 88, one end of which abuts the bottom of the bore 84 and the opposite end of the spring abuts the inner end of a slidable plunger 90. Plunger 90 is cylindrical and closely complementary to the sidewalls of bore 84 for guided movement relative thereto.

Plunger 90, at its outer end, has a detent 92, provided with a preferably hemispherical terminal end. The detent 92 is of a smaller diameter than the main body portion of plunger 90 for purposes of forming an annular shoulder 94 which abuts against a threaded locking sleeve or ring 96 having complementary threads in the bore enlargement 86 for purposes of retaining the plunger 90 and detent 92 in operative position relative to the bore 84 of link 72.

The plunger 90 and detent 92 are integral and preferably are formed from suitable self-lubricating materials such as an appropriate synthetic resin, one appropriate type of which is sold under the trademark NYLON. Other appropriate synthetic resins, including those having comparable frictionfree characteristics and self-lubricating properties may be used in lieu of said specifically mentioned resin. In addition to having suitable wear-resistant and lubricating characteristics, such material is also capable of deadening sound generated during the operation of the latching mechanism, at least to a limited extent.

The outer end of tongue 80 is provided with a notched cam surface 98, somewhat resembling a fiat Z in cross-section as can readily be seen especially in FIGS. 11 and 13. The surface 98 preferably is so shaped that the detent 92 does not bottom in the notch 100, but abuts the sloping surface 102, for example, and thereby maintains the outermost terminal end surface 104 in firm abutment with the bottom or base of slot 78 as can be readily seen from FIG. 11. This arrangement, therefore, releasably maintains the

links

72 and 74 in longitudinal alignmeat.

It is to be understood that while the details of the latching mechanism have been illustrated as being disposed within or upon the

links

72 and 74, such illustration is intended to be exemplary rather than restrictive. Accordingly, the latching plunger 90 and its detent 92, as well as the associated mechanism which supports and operates it may be mounted in link 74 and the tongue 80 with its notched cam surface 98 may be provided on link 72.

The latching arrangement described above and illustrated in FIGS. 11-15 is relatively inexpensive to manufacture due to the ease of fabrication and assembly. The structure affords great tensile strength which is the principal type of stress to which it is subjected in operation to support a chair arm 16 in the so-called lower, arm-supporting position, as shown in FIG. 14. However, when it is desired to move the arm 16 to the raised, or inoperative position, as illustrated in exemplary manner in FIG. 15, it is only necessary to manually or otherwise engage the

links

72 and 74 intermediately of the ends thereof, adjacent to pivotal connection of the same and move said connection laterally, such as rearwardly with respect to the seat 12, for example.

As soon as the longitudinally aligned position of the

links

72 and 74 is changed by such pivotal collapsing or breakage" of the linkage, upward movement of the outer end of the arm 16 will be initiated, whereupon the arm then readily may be raised to the fully elevated position shown in FIG. 15. When the arm 16 is so elevated, the

links

72 and 74 will be disposed within the exemplary position illustrated in FIG. 15, for example.

As in regard to the embodiment illustrated in FIGS. 1-8, for example, it also will be seen that the

connected links

72 and 74 of the embodiment of FIGS. 11-15 also are operable to support the arm 16 in the position shown, for example, in FIG. 4, and in which the back 14 is disposed in reclining position. Further, by collapsing the linkage so that the links are angularly related, as shown, for example, in FIG. 15, whereby arm 16 is elevated to inoperative position, the back 14 may also be lowered under such circumstances from the position shown in FIG. 15 to a substantially horizontal position as shown in FIG. 5, for example, while the arm 16 is still disposed substantially adjacent the side of the back 14.

Also, as described above with respect to the embodiment of the invention shown in FIGS. l-8, the linkage embodiment shown in FIGS. 1 l-15 may be applied to a plurality of arms 16 positioned respectively at opposite sides of the chair seat 12 and back 14, whereby one or both of the arms 16 may be elevated with respect to back 14, as desired.

While the invention has been illustrated and described in its several preferred embodiments, it is to be understood that the invention is not to be limited to the precise details herein illustrated and described since the same may be carried out in other ways falling within the scope of the invention as illustrated and described.

I claim:

1. A chair comprising a seat and back connected to each other, an arm for one side thereof, pivotal means supporting said arm adjacent one end in cantilever manner adjacent one side of said back for pivotal movement of the opposite end of said arm between a lower supporting position for an arm of an occupant and an elevated position to permit unobstructed ingress and egress to and from said side of said seat and back, linkage means positioned adjacent said side of said back and seat and connected at the opposite ends thereof respectively to said pivoted end of said arm and means adjacent the junction of said seat and back, the axis of the pivotal support means for said arm being between the pivotal connection of said linkage means to said arm and the opposite end of said arm, whereby said linkage means is disposed in tension when said arm is in said lower position, and said linkage means being operable to effect support of said arm by said linkage means when in said lower position to provide unobstructed space between said arm and said one side of said seat and also permit raising said arm to said elevated position.

2. The chair according to claim 1 in which said linkage means comprises a pair of links pivotally connected together and said linkage also including positioning means operable to maintain said links in axial alignment and also permit relative pivotal movement of said links for angular positioning of the same with respect to each odier and thereby efiect a contraction of the distance between the opposite pivoted ends of said linkage means to permit the raising of said am to said elevated position thereof.

3. The chair according to claim 2 in which said positioning means comprises a manually slidable sleeve movable to and from a position in which said sleeve encloses the pivotal connection of said two links to each other and thereby locks the same rigidly in axial alignment with each other, and means interconnected to said sleeve and operable to bias the same toward said position in which said sleeve locks said links in axial alignment.

4. The chair according to claim 2 in which said links when in angular retracted position extend away from the forward surface of said back and thereby not interfere with said seat when said arm is in said elevated position thereof.

5. The chair according to claim 2 in which said positioning means comprises a spring connected to one of said links and operable to move said links in a direction to dispose said links in axial alignment with each other, said links further including means thereon adjacent the pivotal connection of the links to each other to prevent pivotal movement between said links in one direction from a position in which they are axially aligned with each other.

6. The chair according to claim 3 in which said back is hingedly connected to the rearward end of said seat for reclining movement of said back rearwardly with respect to said seat, said linkage means being adapted to dispose said arm at an obtuse angle relative to said back when said arm is in the normal lower position thereof and the back is in rearwardly reclined position with respect to said seat.

7. The chair according to claim 1 in which said linkage means is contractible between the outer ends thereof to permit said ends of said linkage means to be moved toward each other and thereby permit raising said arm to an elevated position to dispose the same along one side of said back.

8. The chair according to claim 6 further including brackets respectively disposed along opposite sides of said seat near the rear edge thereof and including pivots connected to said back and one end of said linkage means, said pivots which connect said arms to said back and the pivots by which said linkage means are connected to said arms being aligned approximately parallel to the line of pivots on said brackets, whereby when said back is tilted to reclining position, said arm is disposed at a greater angle to the plane of the back than when said back is upright with respect to the seat and said arm is in said lower position thereof.

9. The chair according to claim 6 in which said linkage means is adapted to support said arm rigidly relative to said back when said back is disposed in a reclining position, whereby said outer free end of said arm may be engaged by an occupant safely to assist the occupant in raising himself from resting upon said lowered back incident to the back being raised toward said nonnal substantially upright position thereof.

10. The chair according to claim 1 in which said linkage means comprises a pair of links pivotally connected together and said positioning means comprises latch means adjacent the pivotal connection of said links, said latch means comprising a spring-pressed detent on one link engageable with cooperating means on the other link when the links are in axial alignment and said latch means being readily releasable manually to permit angular positioning of the links relative to each other and thereby effect a contraction of the distance between the opposite ends of said linkage means to permit raising of said arm to said elevated position thereof.

11. The chair according to claim 10 in which said springpressed detent is movable axially relative to the link which supports the same and the adjacent end of the other link has seat means to receive said detent when said links are in axial alignment.

12. The chair according to claim 11 in which said means to receive said detent is a notched cam surface.

13. The chair according to claim 12 in which the pivotal connection between said links comprises a tongue on the end of one link and a slot in the end of the other link receiving said tongue, and a pivot pin extending transversely through said tongue and the end portions of said other link which define said slot, said notched cam surface being on the outer end of said tongue and said detent projecting outwardly from the base of said slot.

Claims

2. The chair according to claim 1 in which said linkage means comprises a pair of links pivotally connected together and said linkage also including positioning means operable to maintain said links in axial alignment and also permit relative pivotal movement of said links for angular positioning of the same with respect to each other and thereby effect a contraction of the distance between the opposite pivoted ends of said linkage means to permit the raising of said arm to said elevated position thereof.

9. The chair according to claim 6 in which said linkage means is adapted to support said arm rigidly relative to said back when said back is disposed in a reclining position, whereby said outer free end of said arm may be engaged by an occupant safely to assist the occupant in raising himself from resting upon said lowered back incident to the back being raised toward said normal substantially upright position thereof.

11. The chair according to claim 10 in which said spring-pressed detent is movable axially relative to the link which supports the same and the adjacent end of the other link has seat means to receive said detent when said links are in axial alignment.