U.S. patent number 3,661,421 [Application Number 05/074,308] was granted by the patent office on 1972-05-09 for chair arm structure.
This patent grant is currently assigned to Dentsply International Inc.. Invention is credited to Philip C. Johnson.
United States Patent |
3,661,421 |
Johnson |
May 9, 1972 |
CHAIR ARM STRUCTURE
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.
Inventors: |
Johnson; Philip C. (Cincinnati,
OH) |
Assignee: |
Dentsply International Inc.
(York, PA)
|
Family
ID: |
22118887 |
Appl.
No.: |
05/074,308 |
Filed: |
September 23, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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863085 |
Oct 2, 1969 |
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Current U.S.
Class: |
297/411.32;
297/411.39 |
Current CPC
Class: |
A61G
15/10 (20130101); A47C 7/541 (20180801); A47C
1/03 (20130101); A47C 7/543 (20130101) |
Current International
Class: |
A47C
1/03 (20060101); A47C 7/54 (20060101); A47C
1/022 (20060101); A61G 15/00 (20060101); A61G
15/10 (20060101); A47c 007/54 () |
Field of
Search: |
;5/82,114,119
;297/71,162,347,413-417,420 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Nunberg; Casmir A.
Parent Case Text
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.
Claims
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 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.
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 normal 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 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.
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.
Description
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 ophthamology;
otolaryngology, which includes examination and treatment of the
ear, nose and throat; dental examination and 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 the
chair. 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 means of 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-checking means 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
It is the principal object of the present invention to provide
support means for the arms of chairs of the type referred to above
which are entirely free from obstructing the space between said arm
and the seat of a chair when the same is supported 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
arm-supporting 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. 1, 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 of FIG. 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 offers no obstruction to
the seating of a patient upon the seat 12, followed by swinging of
the patient's 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 arm 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
hereinabove.
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 cross-section, 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. 1-8, 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 friction-free 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 flat 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 alignment.
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. 1-8, the linkage embodiment shown in FIGS.
11-15 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.
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