U.S. patent number 3,858,938 [Application Number 05/310,015] was granted by the patent office on 1975-01-07 for chair having leg and foot supporting means.
This patent grant is currently assigned to Landstingens Inkopscentral. Invention is credited to Ove Kristensson, Gunnar Olof August Ridder.
United States Patent |
3,858,938 |
Kristensson , et
al. |
January 7, 1975 |
CHAIR HAVING LEG AND FOOT SUPPORTING MEANS
Abstract
There is provided a chair having a frame supported by two front
chair legs and two rear chair legs and having a back support a seat
and a leg supporting means arranged at the front end of the seat
and capable of being swung from a substantially vertical starting
position to a substantially horizontal supporting position. The leg
supporting means comprises an upper and a lower portion capable of
being moved longitudinally relative each other between fixed
limits, and the lower portion of the leg support means has a foot
support connected adjustably thereto. The lower portion of the leg
supporting means is freely displaceably connected with the upper
portion of said means such that it can move longitudinally relative
said upper portion and its pivot point between determined movement
limits. Longitudinal displacement of the lower portion relative to
the upper portion is guided by a link arrangement adapted to
actuate the lower portion during movement of the leg supporting
means from its starting position to the support position in a
manner such that said lower portion is displaced relative to the
upper portion to an outer limit position, thereby providing an
extension of the leg supporting means so that the foot support does
not impede stretching of the legs of a person sitting in the
chair.
Inventors: |
Kristensson; Ove (Stockholm,
SW), Ridder; Gunnar Olof August (Bromma,
SW) |
Assignee: |
Landstingens Inkopscentral
(Solna, SW)
|
Family
ID: |
20300700 |
Appl.
No.: |
05/310,015 |
Filed: |
November 28, 1972 |
Foreign Application Priority Data
|
|
|
|
|
Dec 2, 1971 [SW] |
|
|
15473/71 |
|
Current U.S.
Class: |
297/423.19;
297/68; 297/423.26 |
Current CPC
Class: |
A61G
5/125 (20161101); A61G 5/128 (20161101); A61G
5/127 (20161101); A61G 5/006 (20130101); A61G
5/1075 (20130101) |
Current International
Class: |
A61G
5/00 (20060101); A61G 5/12 (20060101); A47c
007/50 (); A47c 001/02 () |
Field of
Search: |
;297/71,75,88,330,340-342,429,433,68 ;280/34 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nunberg; Casmir A.
Attorney, Agent or Firm: Colvin; Arthur B.
Claims
What is claimed is:
1. A chair having a frame supported by two front chair legs and two
rear chair legs and provided with a back support, a seat and a leg
supporting means, the latter being arranged at the front end of the
seat and capable of being pivoted from a substantially vertical
starting position to a substantially horizontal supporting
position, the leg support means having a foot support adjustably
connected thereto, characterized in that the leg supporting means
has an upper and a lower portion, said lower portion being freely
displaceably connected with said upper portion so that it can be
displaced longitudinally relative to said upper portion and its
pivot point between determined movement limits, said leg support
having attached to the upper portion thereof a rearwardly extending
arm, operating means arranged beneath the seat, the rear end of
said arm being pivotally connected to said operating means, said
operating means being capable of being moved axially forwards and
backwards to raise and lower the leg support respectively between
its vertical and horizontal positions, said operatiang means having
an outwardly projecting arm having a pivot point, a substantially
vertical link having one end connected to said pivot point, the
other end of said link being pivotally connected to a point on the
lower portion of the leg support, whereby raising of the leg
support causes the first named end of the link to be moved with the
operating means and cause axial movement of the lower portion away
from the upper portion, said back support of said chair being
pivotally mounted at its lower end and collapsible rearwardly, the
lower end of the back support having a bracket forming a pivot arm
relative to the pivot point of the back support, a telescopic
connector joining said bracket with the pivot point of the arm
attached to the upper portion, whereby collapsing movement of the
back support causes the leg support to be raised to its support
position, and during movement of the leg supporting means from its
starting position to the support position said lower portion will
be displaced relative to the upper portion to an outer limit
position, thereby providing an extension of the leg supporting
means so that the foot support does not impede stretching of the
legs of a person sitting in the chair.
2. A chair according to claim 1, characterized in that the
telescopic connector comprises a tube with a rod capable of moving
axially therein, the forward end of the tube being connected with
the arm on the upper portion of the leg support, while the rear end
of the rod is pivotally connected with the bracket on the back
support, whereby when the back support is in its raised position
and the leg support is in its starting position, the rod is
inserted to a bottom portion in the tube so that lowering of the
back support causes pressure forces to be transferred by the inner
end of the rod to the tube and to the arm on the upper portion of
the leg support for raising said leg support.
3. A chair according to claim 2, characterized in that the tube is
provided with a plurality of sequentially arranged latching means a
latching arm is pivotally mounted on the frame of the chair and is
movable to cooperate with any one of said latching means to lock
the leg support in an angular position corresponding to the
latching position of said latching means, and that the arrangement
of said back support permits it to be sequentially raised to the
desired angular position and latched in said position.
4. A chair according to claim 1, characterized in that the leg
first, means has the form of a parallel system of arms, of which
arms a first forms the lower portion of said means and a second
extending generally parallel with said first arm in the collapsed
position of said means and hinged to a fixed seat structure, forms
the upper portion of said means, said first and said second arms
being connected together by further arms in said parallel system in
a manner to permit relative longitudinal movement of the first arm
to the second arm and its pivot point, and in that the parallel
system of arms is held in equilibrium in the collapsed position of
the leg support means by a spring means arranged to act on at least
one of said further arms, said first, arm, when disposed in a
vertical position, being shiftable downwardly by the biasing forces
exerted by said spring means responsive to the application of
downward forces against said foot support, whereby the spacing of
said support from a ground surface may be varied.
Description
The present invention relates to a chair having a frame supported
by two front chair legs and two rear chair legs and provided with a
back support, a seat and a leg supporting means arranged at the
front end of the seat and capable of being swung from a
substantially vertical starting position to a substantially
horizontal supporting position, and having a foot support
adjustably connected thereto.
A necessary feature of chairs fitted with leg and foot supports of
the aforementioned type is that the pivoting axis of the leg
support means must coincide with the axis of the persons's knee
joint sitting in the chair, to ensure that the distance from the
knee joint to the foot support is not changed to any appreciable
extent when raising the leg support. This necessary feature can be
ensured by placing the pivoting axis of the leg support means on
the side of the chair, level with the knee joint. This solution to
the problem, however, impairs the overall aesthetic appearance of
the chair. The object of the present invention is therefore to
provide a chair having a collapsible leg supporting means whose
pivot or journalling points are located inwardly of the confines of
the chair frame and are thus relatively well hidden from view at
the same time as the distance between the knee joint of a person
sitting in the chair and the foot support is not shortened when
raising the leg supporting means. This object is obtained with a
chair constructed in accordance with the present invention, which
is mainly characterized in that the leg supporting means has an
upper and a lower portion of which the lower portion of the leg
supporting means is freely displaceably connected with the upper
portion of said means such that it can move longitudinally relative
said upper portion and its pivot point between determined movement
limits, and that longitudinal displacement of the lower portion
relative to the upper portion is guided by a link arrangement
adapted to actuate the lower portion during movement of the leg
supporting means from its starting position to the support position
in a manner such that said lower portion is displaced relative to
the upper portion to an outer limit position, thereby providing an
extension of the leg supporting means so that the foot support does
not impede stretching of the legs of a person sitting in the chair.
Thus, in accordance with the invention the leg supporting means is
divided into two portions capable of being moved axially in
relation to each other, means being provided for moving said
portions away from each other to lengthen the leg supporting means
when said means is raised, so that the foot support is moved
outwardly to enable the legs of the person using the chair to be
stretched when the leg supporting means is raised to an obliquely
outwardly extending position or a horizontal position. In this way,
it is possible to place the pivoting axis of the leg supporting
means beneath the seat and inwardly of the sides of the seats
without incurring discomfit to the occupant of the chair in the
above indicated manner, and while retaining stability of the chair
when extended.
the
These and other features of the invention will be apparent from the
following description, which is made with reference to an
embodiment of a chair constructed in accordance with theh invention
illustrated in the accompanying drawing.
FIG. 1 is a side view of one embodiment of a chair according to the
invention,
FIG. 2 is a front view of the chair in FIG. 1,
FIG. 3 is a diagrammatic side view of the chair in FIG. 1, showing
the leg supporting means in a horizontal position and the back
support also in a horizontal position,
FIG. 4 illustrates a further embodiment of a chair according to the
invention, and FIG. 5 illustrates diagrammatically another
embodiment of a chair according to the invention and shows in chain
lines a raised position of the leg supporting means and a depressed
position of the footrest.
The chair illustrated in the drawing has a chair frame comprising
steel pipes 10 and supported by four chair legs, each of which has
fitted at the bottom thereof a wheel 12, 14 to enable the chair to
be moved smoothly over the floor.
Since the two sides of the chair are of identical construction, the
following description will only be given with reference to one side
of the chair.
The chair is provided with a collapsible back support 16
cooperating with a bracket or arm 18 and capable of pivoting around
a pivot point 20 located on a bracket structure 22 attached to the
frame 10. When seen in the direction in which the chair is normally
moved, the pivot point 20 is located in front of a vertical line
passing through the point of contact of the rear wheel with the
floor.
The chair is also provided with a seat 24, the rear end of which is
pivotally connected with a pivot point 26 on the arm 18 of the back
support. The pivot point 26 of the seat is located behind a
vertical line passing through the back support pivot point 20 and
on a lower level than said point, when the back support occupies
its raised position as shown in Fig. 1.
The front end portion of the seat is supported by bearing means
which enable the seat to be moved backwards and forwards. In the
illustrated embodiment, the bearing means have the form of
upstanding links 28, the lower ends of which are pivotally
connected with the frame 10 at 30, and the upper ends at 32. which
are pivotally connected with the frame of the seat at32.
A gas spring 34 is arranged to assist in raising and lowering the
back support 16, the gas spring being operable by means of a handle
36 (FIG. 3) which in a first position disconnects the gas spring to
permit the back support to be laid flat, and a second postion in
which the gas spring is made operative for raising the back
support. The gas spring may optionally be replaced with a system of
links capable of being operated by means of a lever placed on the
side of the chair.
When the back support is collapsed rearwardly from the position
shown in FIG. 1, the seat pivot point 26 will be moved downwardly
and forwardly, causing the rear end of the seat 24 to be lowered
and the seat to be moved forward. To this end, the bearing means at
the front end of the seat are arranged so that the seat takes a
relatively pronounced rearwardly inclined position when the back
support 16 is collapsed to an intermediate position, between its
raised position as shown in FIG. 1 and its horizontal position as
shown in FIG. 3. With this arrangement, the person occupying the
chair is seated more firmly when the back support is dropped
rearwardly than would be the case if the seat were permitted to
retain its horizontal or slightly rearwardly inclined position as
shown in FIG. 1.
Owing to the fact that the seat is simultaneously moved forward as
the back support is lowered, the centre of gravity of the person
sitting in the chair is also moved forward to a point located
further inwardly of the rear wheels 14, whereby the chair retains
its stability to a greater extent than would be the case if the
centre of gravity of the occupant was not moved.
The chair illustrated in FIG. 1 is provided with two pivotable leg
supports 38 which are of identical construction and hence of which
only one will be described hereinafter. In FIG. 1 the leg support
is shown collapsed to a substantially vertical position, while FIG.
3 illustrates the leg support raised to a horizontal position.
The leg support 38 is divided into portions, comprising an upper
portion 40 and a lower portion 42 capable of being moved axially in
relation to the upper portion 40 in the longitudinal direction of
the leg of the occupant. The upper portion 40 is pivotally
connected at the upper end thereof with the seat frame at 44. The
upper portion 40 comprises a bar or rod extending downwardly in a
sleeve forming the lower portion 42. Pivotally mounted at the lower
end of the sleeve 42 is a foot support 46.
When the leg support is raised to its horizontal position, as shown
in FIG. 3, a system of links causes the lower portion 42 to be
slightly moved axially away from the upper portion, to increase the
distance between the pivot point 44 of the upper portion and the
foot support 46. Thus, in this way there is obtained an increase in
the length of the leg support in a particularly simple manner. The
knees of a person sitting in the chair with the back support and
leg support occupying the position illustrated in FIG. 1 will be
level with the upper side of the seat and slightly in front of its
leading edge. Since the occupant's legs swing around a pivot point
which does not coincide with the pivot point 44 of the upper
section, the seat, subsequent to being swung to the horizontal
position, will extend beyond the extremities of the foot support 46
in FIG. 1 if the foot support 46 with its lower portion should be
securely connected to the upper section 40. With the described
arrangement, however, the foot support is automatically extended by
an amount sufficient to hold the legs of the person sitting in the
chair straight with the feet resting on the foot support. The
manner in which this can be accomplished simply but effectively
will be evident from the illustrated example of the link
system.
Mounted on the rear side of the upper portion 40 is a bracket arm
48 having a pivot point 50 lying behind a vertical line passing
through the pivot point 44 of the upper portion when the leg
support occupies its collapsed position. Between the pivot point 50
and the pivotable arm 18 of the back support is mounted at 52 a
telescopic link, comprising a tube 54 attached at pivot point 50,
and a rod 56 capable of moving axially in the tube 54, the inner
end of the rod 56 engaging the bottom of the tube 54 at its inner
end in the position illustrated in FIGS. 1 and 3, and the outer end
of which rod is connected with the back support bracket at the
point 52. When the back support is collapsed rearwardly to the
position shown in FIG. 3, the leg support 38 is swung up to its
horizontal position, FIG. 3. The leg support can be latched in this
position by a latching arm 58 capable of being operated by a handle
60 and pivotably mounted in the seat frame at 62. The lower end 64
of the latching arm 58 can be brought into engagement with one of a
number of raised members 66 (FIG. 5) arranged on the tube 54, the
selected raised member corresponding to the desired angle of the
leg support in its extended position. In FIG. 3, the leg support is
shown to occupy a horizontal position. If desired, the back support
can now be raised by means of the gas spring 34 to the desired
angle, this being enabled by virture of the fact that the rod 56 is
freely displaceable in the sleeve 54.
To provide for outward movement of the lower portion 42 of the leg
support when lifting said support there is provided an obliquely
upwardly extending arm 68 at the end of the tube 54. The arm 68 is
moved forward by the telescopic link arrangement 54, 56 from the
position shown in FIG. 1 to the position shown in FIG. 3. This
movement is transmitted to the lower portion 42 by means of a link
70, one end of which is pivotally connected to the arm 68 at 72,
and the other end of which is pivotally connected at a point 74 on
the lower section 42.
The chair illustrated in FIG. 1 is constructed as a wheel chair and
may be used to advantage by handicapped persons. By providing the
chair with a seat which can be moved forward when the back support
is lowered, and with a leg support which can be extended when
raising said support, as shown in FIG. 3, there is obtained a
particularly comfortable and safe wheel chair which can be readily
converted to a horizontal and stable bed-like structure with
sufficient room for the legs, as with FIG. 3, when so desired.
FIG. 4 illustrates a modification of the embodiment illustrated in
FIG. 1. The embodiment of FIG. 6 also includes an upper portion 40
pivotally mounted at 44. The design of the rearwardly directed
bracket or arm 48a, anchored to the upper section 40, is somewhat
changed, but operates in principle in the same manner as the arm 48
in FIG. 1, owing to the fact that its rear end is pivotally
connected with the operating means, i.e. the tube 54, at a point
50a. The embodiment of FIG. 6 also includes a lug or an obliquely,
outwardly extending arm 68a attached to the front end of the tube
54 and pivotally connected at its upper, free end 72a with the
upper end of a link arm 70a, the lower end of which link arm 70a is
pivotally connected with the lower portion 42. With the embodiment
of FIG. 4, the link arm 70a is located in front of the upper and
the lower section and extends down to the proximity of the foot
support. By means of this arrangement, the link arm will be
extended slightly in relation to the lower portion 42 when the leg
support is raised to an intermediate position. Supported by the
link arm is a calf support member 76, which is arranged to support
the calf of the leg during practically the whole of the raising
movement performed by the leg support. When the leg support
occupies its horizontal position, the calf supporting member is
approximately in register with the seat 24.
FIG. 5 illustrates a further embodiment of a leg support means
constructed in accordance with the concept of the invention. As
with the embodiments of the chair illustrated in FIGS. 1-4, the leg
support means of this embodiment comprises an upper portion and a
lower portion, the lower portion having a foot rest attached
thereto and being connected to the upper portion in a manner to
permit limited longitudinal movement thereof relative to the upper
portion and to the pivot point of said upper portion.
With this embodiment, the lower portion of the leg support
comprises an arm 80 forming part of a parallel linkage system,
shown generally at 81, so arranged that movement of the leg support
means from its collapsed to its raised position can be effected
without shortening the distance from the knee joint of a person
occupying the chair to the foot rest. The foot rest, shown at 46,
is attached to the lower portion or arm 80 by means of a rod or the
like 82, the position of which relative the arm 80 can be locked by
means of a latch pin 83, for example. Extending generally parallel
with the arm 80 when the leg supporting means occupies its
collapsed position is a portion 84 of an arm forming the upper
portion of the leg supporting means, the other portion 85 of which
arm is pivotally attached to the underside of the seat frame at 86.
The longitudinal movement of the lower portion or arm 82 relative
the upper portion or arm 84, 85 and its pivot point 86 is
facilitated and controlled by two arms 87 and 88 which interconnect
arms 82 and 84 and which are pivotally connected thereto at 89, 90
and 91, 92 respectively. The arms 82, 84, 87 and 88 form a
generally parallel system of link arms when the leg supporting
means occupies its collapsed position.
To maintain the parallel linkage system in equilibrium in the
collapsed, vertically extending position of the leg support there
is provided a spring 92. In the illustrated embodiment the spring
is a compression spring and extends over a rod 93 between an
adjustable stop member 94 and a sleeve 95 arranged to move along
the rod 93 to compress or relax the spring; a further stop member
95a is arranged beneath the sleeve 95 on rod 93 to provide a bottom
movement limit for the sleeve. The end of the rod remote from the
sleeve 95 is pivotally attached at 95b to a link arm actuating
mechanism, hereinafter described, while an extension of arm 88 is
attached to the sleeve 95 in the manner illustrated.
As will be obviius from the aforegoing and from the Figure, when a
load is applied to the foot rest 46, for example as an occupant of
the chair prepares to leave the same, the downardly acting force on
arm 82 will cause arm 88, which is attached to the sleeve 95 of the
spring means, to pivot about its pivot point 92a against the force
exerted by the spring 92. The end of the rod 93 bearing the stop
member 95a may be threaded and the stop member, provided with a
corresponding internal thread, to enable the distance between the
upper and lower limits of movement for the sleeve 95 to be
adjusted, and therewith also the degree of precompression of the
spring 92.
In addition to providing for a smooth and controlled vertical
movement of the lower portion of the leg support means and the foot
rest when a load is applied to the latter, the restraining force of
the spring will also counteract forward tilting movement of the
chair as the occupant stands on the foot rest when climbing into
and out of the chair.
As with the embodiments previously described, movement of the leg
supporting means from its collapsed position to its raised position
is accomplished by means of a telescopic link, comprising a hollow
tube 96 and a rod 97 arranged to move axially in the tube. The
telescopic link 96, 97 is constructed and operates in the same
manneras the telescopic link 54, 56 of FIG. 1, and the outer end of
the rod 97 is therefore connected to a back support bracket 98 at
99. The end of the tube remote from the bracket 98 is connected to
the upper portion or arm 54, 85 and as will be seen from FIG. 5,
the tube 96 also carries the attachment point 95b for the spring
92. The aforedescribed telescopic link arrangement may be emobdied
both when the leg support means shall be capable of being raised
independently of the back rest and when lifting or lowering of the
leg support means is effected simultaneously with corresponding
movements of said back rest. In this latter instance, however, the
telescopic link may be replaced withh any suitable form of drive
means, such as a triangular rod-like structure arranged to respond
to movement of the back rest so as to move the leg support means in
a corresponding manner.
When wishing to raise the leg support means from its collapsed
position, pressure is applied to the rod 97, which bears against
the closed end of the tube 96. Movement of the rod 97 will then
cause the arm 84 to swing outwardly and upwardly about its pivot
86, the arms 88 and 89 connected to the arm 84, 85 and to the arm
80 transferring the movement of arm 84, 85 to arm 80, whereupon the
arm or lower portion 80 of the leg support means also swings
outwardly and upwardly to the desired position.
As before mentioned, the arrangement of arms 80, 84 85, 87 and 88
is such that as the lower portion of the leg support means is moved
outwardly and upwardly under the influence of a similar movement of
arm 84, 85, the arm 80 is moved longitudinally relative to the arm
portion 84 to a determined extent, thereby ensuring that the
distance from the knee joint of the chair occupant to the foot rest
46 is not shortened as the leg support is raised.
As the arm 80 moves upwardly and outwardly in the manner described,
the spring 92 will accompany the movement of arm 88 while pivoting
about pivot point 95b, to serve as a locking link in the raised
position of the leg support means, through the telescopic link 96,
97, which is suitably locked in its extended position by
appropriate means, such as by the latching arm arrangement
described in connection with the embodiment of FIG. 1.
Although the concept of the present invention has been illustrated
by a number of embodiments in which the concept is applied, it will
be obvious that many alternatives are possible by which the lower
portion of the leg supporting means can be made to automatically
move longitudinally relative the upper portion as the leg
supporting means is raised from its vertical collapsed position.
Further, the spring means 62 can be replaced by any suitable means
capable of permitting controlled depression of the foot rest in the
vertical and extended position of the leg support means and of
serving as a locking arm in said extended position of said means.
If the feature of the depressible foot rest is not required, the
spring means may be replaced by a rigid link arm. The invention is
therefore not restricted to the described and illustrated
embodiments, but can be modified within the scope of the following
claims.
* * * * *