U.S. patent application number 17/617683 was filed with the patent office on 2022-08-04 for tiltable stool.
This patent application is currently assigned to Inventor Group GmbH. The applicant listed for this patent is Inventor Group GmbH. Invention is credited to Thomas Walser.
Application Number | 20220240681 17/617683 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-04 |
United States Patent
Application |
20220240681 |
Kind Code |
A1 |
Walser; Thomas |
August 4, 2022 |
Tiltable Stool
Abstract
A tiltable stool includes a seat which is connected to a base by
an elongated body structure. The base has an upper base element and
a lower base element. The upper base element is resiliently
deformable. The resiliently deformable upper base element allows
the stool to pivot in any direction. The lower base element is a
rotationally symmetrical outwardly convex and inwardly concave
body. The upper base element may include one or more annular
grooves.
Inventors: |
Walser; Thomas;
(Kreuzlingen, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Inventor Group GmbH |
Wollerau |
|
CH |
|
|
Assignee: |
Inventor Group GmbH
Wollerau
CH
|
Appl. No.: |
17/617683 |
Filed: |
June 10, 2020 |
PCT Filed: |
June 10, 2020 |
PCT NO: |
PCT/IB2020/055459 |
371 Date: |
December 9, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62859314 |
Jun 10, 2019 |
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International
Class: |
A47C 9/00 20060101
A47C009/00; A47C 7/00 20060101 A47C007/00; A47C 3/025 20060101
A47C003/025; A47C 3/026 20060101 A47C003/026 |
Claims
1. A tiltable stool, comprising: a seat; an upper base element; a
body structure extending between the seat and the upper base
element, the body structure being firmly connected to a central
portion of the upper base element; and a lower base element, the
lower base element having an annular upper end firmly connected to
an annular outer portion of the upper base element, wherein the
upper base element is resiliently deformable and includes a portion
having a U-shaped profile.
2. The tiltable stool as in claim 1, wherein the lower base element
is a rotationally symmetrical outwardly convex and inwardly concave
body extending from the annular upper end to an annular lower
end.
3. The tiltable stool as in claim 1, wherein the lower base element
and the upper base element are connected to each other with a
tongue and groove joint.
4. The tiltable stool as in claim 1, wherein the lower base element
comprises an upwardly facing tongue which engages a downwardly open
groove in the upper base element.
5. The tiltable stool as in claim 1, wherein an outer surface of
the upper base element and an outer surface of the lower base
element transition seamlessly into one another.
6. The tiltable stool as in claim 1, wherein the upper base element
is made of a resiliently deformable material and the lower base
element is made of an inelastic material.
7. The tiltable stool as in claim 1, wherein both the upper base
element and the lower base element are made of resiliently
deformable material.
8. The tiltable stool as in claim 1, wherein the upper base element
comprises an annular groove in the portion having the U-shaped
profile.
9. The tiltable stool as in claim 8, wherein the annular groove is
deeper than it is wide.
10. (canceled)
11. The tiltable stool as in claim 8, wherein the annular groove is
arranged concentrically around and proximal to the central
portion.
12. (canceled)
13. The tiltable stool as in claim 8, wherein the annular groove
has an inner side wall and an outer side wall, wherein upper
portions of the inner side wall and the outer side wall are
arranged at a distance from one another when the tiltable stool is
in an upright position, and wherein the upper portions of the inner
side wall and the outer side wall touch when the tiltable stool is
deflected and reaches a maximum tilt angle.
14. The tiltable stool as in claim 8, further comprising a tilt
angle adjustment ring which is axially displaceable along a
longitudinal axis of the body structure, the tilt angle adjustment
ring having a lower portion which engages the annular groove at a
selectable depth.
15. The tiltable stool as in claim 14, wherein a maximum tilt angle
of the body structure is limited by selecting the selectable depth
of the lower portion of the tilt angle adjustment ring in the
annular groove.
16. The tiltable stool as in claim 1, wherein the upper base
element comprises a plurality of concentric and radially spaced
annular grooves.
17. The tiltable stool as in claim 16, wherein the annular grooves
have a generally U-shaped cross-sectional profile.
18. The tiltable stool as in claim 16, wherein the annular grooves
are filled with a compressible compound.
19. The tiltable stool as in claim 16, wherein the annular grooves
are wider than they are deep.
20. (canceled)
21. The tiltable stool as in claim 1, wherein the seat is pivotably
mounted to an upper end of the body structure.
22. The tiltable stool as in claim 1, wherein the seat comprises an
upper seat member which is firmly attached to a lower seat member,
and wherein the lower seat member includes a U-shaped lower seat
member portion which is configured to deform and allow the seat to
pivot relative to the body structure.
23. The tiltable stool as in claim 22, wherein a width of the
U-shaped lower seat member portion determines a maximum pivot angle
of the seat relative to the body structure.
24. (canceled)
Description
TECHNICAL FIELD
[0001] The present disclosure generally relates to an article of
furniture, and more particularly, to a tiltable stool or chair.
BACKGROUND
[0002] Articles of furniture such as stools or chairs which allow a
user to rock forward, backward and sideways are generally known. A
tiltable stool is typically configured to be used on a generally
horizontal surface such as a floor. The stool comprises a top
portion providing a seat and a base portion comprising a bottom
surface configured to support the stool on the floor.
[0003] An example of a tiltable stool is disclosed in the
applicant's U.S. Pat. No. 9,894,998 which is hereby incorporated by
reference thereto in its entirety.
SUMMARY
[0004] A tiltable stool includes a seat, a base, and a body
structure extending between the seat and the base. The base
includes at least an inner base element and an outer base element.
The outer base element extends outwardly around the inner base
element. The body structure is firmly connected to a central
portion of the inner base element. The outer base element has an
annular upper end extending outwardly around the inner base element
and a rotationally symmetrical outwardly convex and inwardly
concave body extending from the annular upper end to an annular
lower end. The outer base element or the inner base element is
resiliently deformable, thereby allowing the body structure to
pivot in any direction.
[0005] The inner base element and the outer base element may be
connected to each other with a tongue and groove joint. In
particular, the outer base element may have an inwardly facing
tongue which engaged an outwardly open groove in the inner base
element.
[0006] An upper surface of the inner base element and an upper
surface of the outer base element may be arranged in a common
plane. The upper surface of the inner base element and the upper
surface of the outer base element may transition seamlessly into
one another.
[0007] The inner base element may have an outwardly facing
cylindrical support surface which abuts a corresponding inwardly
facing cylindrical support surface of the outer base element. The
outer base element may have an inwardly facing tongue which engages
an outwardly open groove in the inner base element. In this
configuration the outwardly facing cylindrical support surface of
the inner base element may be arranged above the groove and the
inwardly facing cylindrical support surface of the outer base
element may be arranged above the tongue.
[0008] The inner base element may be made of an inelastic material
and the outer base element may be made of a resiliently deformable
material. Alternatively, the inner base element may be made of a
resiliently deformable material and the outer base element may be
made of an inelastic material. In yet another alternative both the
inner base element and the outer base element may be made of
resiliently deformable material.
[0009] An adjustment disk may be arranged at a variable height
below the inner base element. A maximum tilt angle of the body
structure may then be limited by selecting the variable height of
the adjustment disk below the inner base element. The body
structure may extend through the inner base element and the
adjustment disk may comprise an inner thread which engages a
corresponding outer thread arranged at a lower end of the body
structure. The adjustment disk may be configured to push against
the outer base element when a maximum tilt angle of the body
structure has been reached.
[0010] The outer base element may have a generally C-shaped cross
section. The inner base element may be generally disk-shaped. The
inner base element may be made of spring steel and include a
plurality of circumferentially distributed slots extending outward
away from its central portion.
[0011] The seat of the stool may be pivotally mounted to an upper
end of the body structure.
[0012] In another example, a tiltable stool includes a seat, a
resiliently deformable inner base element, and a resiliently
deformable outer base element extending outwardly around the inner
base element. A body structure extends between the seat and the
inner base element. The body structure is firmly connected to a
central portion of the inner base element. The inner base element
and the outer base element each form a spring damper system,
allowing the body structure to pivot in any direction by deforming
the inner base element and the outer base element. A damping factor
of the outer base element is larger than a damping factor of the
inner base element.
[0013] In a different configuration, a tiltable stool has a seat,
an upper base element, a lower base element, and a body structure
extending between the seat and the upper base element. The body
structure is firmly connected to a central portion of the upper
base element. The lower base element has an annular upper end
firmly connected to an annular outer portion of the upper base
element. The upper base element is resiliently deformable.
[0014] The lower base element may be a rotationally symmetrical
outwardly convex and inwardly concave body extending from the
annular upper end to an annular lower end.
[0015] The lower base element and the upper base element may be
connected to each other with a tongue and groove joint. In
particular, the lower base element may comprise an upwardly facing
tongue which engages a downwardly open groove in the upper base
element.
[0016] An outer surface of the upper base element and an outer
surface of the lower base element may seamlessly transition into
one another.
[0017] The upper base element may be made of a resiliently
deformable material and the lower base element may be made of an
inelastic material. Alternatively, both the upper base element and
the lower base element may be made of resiliently deformable
material.
[0018] The upper base element may comprise an annular groove. The
annular groove may be deeper than it is wide. The annular groove
may have an inner side wall and an outer side wall. The inner side
wall and the outer side wall may be arranged at an angle towards
one another when the tiltable stool is in an upright position. The
annular groove may be arranged concentrically around and proximal
to the central portion.
[0019] The annular groove may have a generally V-shaped
cross-sectional profile with a flat bottom.
[0020] The annular groove may have an inner side wall and an outer
side wall.
[0021] Upper portions of the inner side wall and the outer side
wall may be arranged at a distance from one another when the
tiltable stool is in an upright position. The upper portions of the
inner side wall and the outer side wall may touch when the tiltable
stool is deflected and reaches a maximum tilt angle.
[0022] The tiltable stool may include a tilt angle adjustment ring
which is axially displaceable along a longitudinal axis of the body
structure. The tilt angle adjustment ring may have a lower portion
which engages the annular groove at a selectable depth. A maximum
tilt angle of the body structure may be limited by selecting the
selectable depth of the lower portion of the tilt angle adjustment
ring in the annular groove.
[0023] The upper base element of the tiltable stool may include a
plurality of concentric and radially spaced annular grooves. The
annular grooves have a generally U-shaped cross-sectional profile.
The annular grooves may be filled with a compressible compound.
[0024] The annular grooves may be wider than they are deep.
[0025] The upper base element may be generally disk-shaped.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 shows a cross section of a first example of a base of
a tiltable stool.
[0027] FIG. 2 shows a cross section of a second example of a base
of a tiltable stool.
[0028] FIG. 3 shows a cross section of a third example of a base of
a tiltable stool.
[0029] FIG. 4 shows a perspective cross section of a fourth example
of a base of a tiltable stool.
[0030] FIG. 5 shows a cross section of a fifth example of a base of
a tiltable stool.
[0031] FIG. 6 shows a cross section of a sixth example of a base of
a tiltable stool.
[0032] FIG. 7 shows a cross section of a seventh example of a base
of a tiltable stool in a normal state.
[0033] FIG. 8 shows the base of FIG. 7 in a deflected state.
[0034] FIG. 9 shows a cross section of an eighth example of a base
of a tiltable stool in a normal state.
[0035] FIG. 10 shows the base of FIG. 9 in a deflected state.
[0036] FIG. 11 shows a cross section of a stool.
[0037] FIG. 12 is a diagram showing a mechanical spring and damper
configuration.
[0038] FIG. 13 is a cross sectional view of a stool base showing an
inner base member with conical lower surface.
[0039] FIG. 14 is a cross sectional view of a stool base showing an
inner base member with conical upper surface.
[0040] FIGS. 15-17 show a cross sectional profile of a stool base
with an annular groove.
[0041] FIGS. 18-20 show a cross sectional profile of a stool base
with a plurality of annular grooves.
[0042] FIGS. 21 and 22 show a cross sectional profile of a stool
base with a corrugated upper base element.
[0043] FIG. 23 is a partially cut perspective view of the stool
base as in FIG. 22.
[0044] FIG. 24 is a partially cut perspective view of the stool
base as in FIG. 19.
[0045] FIG. 25 is a cross sectional profile of a stool base with
annular grooves and a cover.
[0046] FIG. 26 is a cross sectional profile of a stool base with
annular grooves formed in an intermediate part.
[0047] FIG. 27 is a cross sectional profile of a stool base with
annular grooves formed in an intermediate part.
[0048] FIG. 28 is a cross sectional profile of a stool base with
annular grooves and rollers.
[0049] FIG. 29 is a cross sectional profile of a stool.
DETAILED DESCRIPTION
[0050] Referring to FIGS. 1 and 11, a tiltable stool 1 has a seat
2, a base 3, and an elongated body structure 4 between the base 3
and the seat 2. The stool 1 may comprise a height adjustment
mechanism including an adjustment lever 7 to adjust the length of
the body structure 4. The body structure 4 may comprise a pillar
assembly and defines a vertical axis 5 of the stool 1.
[0051] The base 3 may include an inner base element 20 which is
connected to an outer base element 10. The body structure 4 is
firmly connected to a central portion 29 of the inner base element
20. The central portion 29 may include a receiving opening for a
lower portion of the body structure 4. The outer base element 10 is
configured to rest on a floor.
[0052] The outer base element 10 or the inner base element 20 is
resiliently deformable. This allows the body structure 4 to pivot
in any direction by deforming the resilient element of the base 3.
Throughout this specification and the following claims, the
coordinating conjunction "or" is not used to express exclusivity.
That is, the outer base element or the inner base element being
resiliently deformable means that either the outer base element
alone is resiliently deformable, that the inner base element alone
is resiliently deformable, or that both the outer base element and
the inner base element are resiliently deformable.
[0053] When a tilting force is applied to the seat, the seat is
moved from a normal position into a dynamic seating position.
Typically, the normal position is upright. In the upright position,
the vertical axis 5 of the stool 1 is perpendicular to the floor.
In response to a tilting force, the resilient element of the base 3
is deformed, and the vertical axis 5 of the stool 1 is tilted by a
tilt angle .alpha. out of the normal position.
[0054] The outer base element 10 surrounds and is firmly connected
to the inner base element 20. In particular, an upper annular end
of the outer base element is connected to an outer rim of the inner
base element. The inner base element 20 may be connected to the
outer base element 10 by a tongue and groove joint. As shown in
FIG. 1, the outer base element 10 may include an inwardly facing
tongue 11 which engages an outwardly open groove 21 in the rim of
the inner base element 20. The tongue-and-groove connection may
also use an outwardly facing tongue arranged on the inner base
element 20 and an inwardly open groove at the outer base element
10.
[0055] The inner base element 20 and the outer base element 10
preferably transition seamlessly, i.e. smoothly and without gaps,
into one another. An upper surface 26 of the inner base element and
an upper surface 16 of the outer base element may be arranged in a
common plane. The upper surface 26 of the inner base element and
the upper surface 16 of the outer base element thereby transition
seamlessly into one another.
[0056] The inner base element may have an outwardly facing
cylindrical support surface 27 at its outer rim. This outwardly
facing cylindrical support surface 27 abuts a corresponding
inwardly facing cylindrical support surface 17 of the outer base
element. In combination with a tongue and groove joint the
outwardly facing cylindrical support surface 27 of the inner base
element 20 and the inwardly facing cylindrical support surface 17
of the outer base element 10 are arranged in a plane axially spaced
above the tongue 11 and groove 21. The support surfaces 17, 27 are
generally vertically oriented.
[0057] The inner base element 20 may be generally disc-shaped
having a generally vertically oriented, i.e. cylindrical, outer
rim. The outer rim may alternatively have a frustoconical shape, in
which case the support surfaces between the inner base element and
the outer base element may also be frustoconical.
[0058] The desired tiltability of the stool can be achieved in that
the inner base element is made of an inelastic material and the
outer base element is made of a resiliently deformable material.
Within the scope of this specification and the following claims, a
material will be considered inelastic if a part made thereof, when
the same is subjected to typical forces occurring in a stool, do
not lead to a noticeable deformation of the part. An inelastic
material may also be referred to as rigid. A material will be
considered resiliently deformable, or simply resilient, if a part
made thereof, when the same is subjected to typical forces
occurring in a stool, does elastically deform and resume its
original shape when no longer subjected to the typical forces.
Within a stool forces up to 2500 N are typical.
[0059] The desired tiltability can also be achieved by making the
inner base element from a resiliently deformable material and the
outer base element from an inelastic material. In yet another
variation both the inner base element and the outer base element
may be made of resiliently deformable material. In that case, the
inner base element and the outer base element are preferably made
of different materials, and in particular of materials having
different hardness.
[0060] The resilient element of the base 3 may be made of
thermoplastic polyurethane (TPU), rubber, thermoplastic polyolefin
(TPO), fiberglass enforced polyamide (PA) or fiberglass enforced
polyurethane (PU). The selection of material requires a trade-off
decision between cost and functionality. Experiments including
durability tests have shown, that a thermoplastic polyurethane with
90 A Shore hardness provides the required robustness at an
affordable price. An outer base element 10 made of softer TPU with
75 A Shore hardness would require about twice the amount of
material as one made of TPU with 90 A Shore hardness.
[0061] The inelastic element of the base 3 may be made of metal,
e.g. aluminum, or steel, or be made of a hard plastic, e.g. a
plastic with greater than 100 A Shore hardness.
[0062] Shown in FIGS. 1 and 2 is a configuration in which the inner
base element 20 is made of a rigid material and the outer base
element 10 is made of a resilient material. In this configuration,
the shape of the outer base element 10 primarily determines how
sitting on the stool feels to a user. The user primarily observes
how the stool moves downwardly in response to vertical forces. This
characteristic may be expressed as a vertical spring constant of
the stool. The user will also observe how easily the stool pivots,
i.e. how strongly the stool pushes back against horizontal forces
applied to the seat.
[0063] The shape of the outer base element 10 can be defined by
several characteristic metrics as illustrated in FIG. 2. Among
those characteristic metrics are the height h of the outer base
element 10, its thickness t, the diameter D.sub.u of its circular
upper end, the diameter D.sub.b of its circular lower end, and its
maximum diameter D.sub.max between the upper end and the lower
end.
[0064] While experiments have been conducted with parts of certain
dimensions, the absolute size of those parts may be scaled, leaving
characteristic proportions that have been found to be
beneficial:
D max / D u : > 1.2 ##EQU00001## D max / h : 3 - 10
##EQU00001.2## D max / D b : 1.05 - 2 ##EQU00001.3## t / h : 0.05 -
0 . 3 .times. 5 ##EQU00001.4##
[0065] Generally, use of a thicker and software material (e.g.
between 75-85 A Shore) for the outer base element should be
considered for high-end products where comfort and service life of
the product are critical. For lower cost models it is desirable to
reduce the mass of the outer base member to ideally less than 1 kg,
which can be accomplished by using thinner and harder material
(e.g. above 90 A Shore).
[0066] The outer base element 10 may have a generally C-shaped
cross section. As illustrated in FIG. 1, the outer base element 10
may be formed as one piece, but functionally divided into an upper
section 12, a center section 13, and a lower section 14. As
indicated by dotted lines the upper section 12 may extend from the
upper end to a virtual line which cuts the outer surface of the
outer base element perpendicularly at a 45.degree. upward angle.
The lower section 14 may extend from the lower end to a virtual
line which cuts the outer surface of the outer base element
perpendicularly at a 45.degree. downward angle.
[0067] A differently shaped outer base element is illustrated in
FIG. 5. Here, the lower section 54 of the outer base element is
shaped as a generally flat ring. The center section 53 is generally
cylindrical having vertical walls. The upper section 52 has a
generally rounded circular cross section.
[0068] While the outer base element 10 will preferably be formed as
one piece, it may also be formed in two pieces as shown in FIG. 3.
For example, the outer base element may consist of an upper outer
base element 32 that is joined to a lower outer base element 34 by
a joint 35. The upper outer base element 32 and the lower outer
base element 34 may be made of different hard materials.
[0069] FIGS. 7 and 8 show a configuration in which the outer base
element 72 is made of a rigid material which the inner base element
71 is made of a resilient material.
[0070] FIG. 4 shows a configuration in which both the outer base
element and the inner base element 40 are made of resilient
material. To improve its elasticity the inner base element 40
includes a plurality of circumferentially distributed slots 41
which extend outward away from the central portion. The slots 41
extend diagonally, i.e. with a radial and a circumferential
component, from the central portion towards the rim of the inner
base element. While diagonal slots have proven to be beneficial, in
particular, if the inner base element is not completely flat,
radially extending slots without a circumferential component can be
used in flat parts.
[0071] It may be desirable to limit the tilt of the stool to a
maximum tilt angle and to allow a user to adjust this maximum tilt
angle. This can be accomplished by providing an adjustment disk 61
as shown in FIG. 6. The adjustment disk 61 is connected to the
lower end of the body structure 4. A central axis of the adjustment
disk 61 is concentric with the vertical axis 5 of the stool 1. As
the stool 1 tilts, so does the adjustment disk 61.
[0072] The adjustment disk 61 is wide, such that an outer rim of
the adjustment disk, upon reaching the maximum tilt angle, pushes
against an inner surface of the outer base element. The stool 1 can
tilt no further than permitted by the height between the outer rim
of the adjustment disk 61 and the inner surface of the outer base
element underneath.
[0073] The position of the adjustment disk 61 within the base may
be adjustable. For example, a lower portion of the body structure 4
may extend through the inner base element with a threaded end. The
threaded end of the body structure may be connected with a threaded
central opening of the adjustment disk 61. By rotating the threaded
adjustment disk 61 within the base it can thus move up and down as
indicated by a lower position 61' in dotted line and an upper
position of the adjustment disk 61 shown in solid line in FIG. 6.
In the lower position 61', tilt of the stool is significantly
limited. Here, the adjustment disk 61' leaves very little space for
the stool to tilt until the adjustment disk pushes against the
outer base element.
[0074] The concept of limiting the maximum tilt angle of the stool
by an adjustment disk can also be applied to the configuration with
a resilient inner base element 71 and rigid outer base element 72
shown in FIGS. 7 and 8. Such a configuration is shown in FIGS. 9
and 10. Here, the adjustment disk 91 is also provided in a
height-adjustable arrangement within the base. However, the maximum
tilt of the stool is limited when the adjustment disk 91 pushes
against an upper portion of the outer base element. As shown, the
maximum tilt of the stool is very limited when the adjustment disk
91 is in an upper position 90, while the maximum pivot angle of the
stool is larger when the adjustment disk is in a lower position
92.
[0075] In either configuration, the adjustment disk is arranged
within the base at a variable height below the inner base element.
A maximum tilt angle of the body structure is limited by selecting
the variable height of the adjustment disk below the inner base
element.
[0076] The stool shown in FIG. 11 uses the same general structure
of an inner base element 20 and an outer base element 10. In this
configuration both the inner base element 20 and the outer base
element 10 are made of resilient material. The outer base element
10 may be made of a thermoplastic material having a hardness of
about 80 A-90 A Shore. The inner base element 20 is preferably made
of spring steel. As shown, the outer base element 10 overlaps the
inner base element 20. The inner base element 20 is connected to
the outer base element 10 in that the inner base element 20 engages
an undercut of the outer base element 10. The relative softness of
the outer base element 10, in particular if still warm after
molding or if heated, allows sliding the outer base element 10 onto
the inner base element 20 by stretching the outer base element 10
and allowing the inner base element 20 to engage the undercut of
the outer base element.
[0077] While a force fit connection between the inner base element
and the outer base element is preferred for recyclability, the
inner base element may also be welded (e.g. by ultrasonic welding)
or glued to the outer base element. The outer base element may also
be overmolded onto the inner base element. The inner base element
and the outer base element may also be produced by multi-material
injection molding.
[0078] Since both the inner base element 20 and the outer base
element 10 are resiliently deformable, both deform when the stool
is tilted. Surprisingly though, the dynamic response of the inner
base element 20 and the outer base element 10 to a sudden lateral
movement of the seat 2 can be quite different. Both the inner base
element 20 and the outer base element 10 can be considered damped
spring systems. The damping factor of the outer base element 10 is
significantly larger than the damping factor of the inner base
element 20. The different damping factors are attributed to the
choice of materials (spring steel vs. thermoplastic) and their
relative sizes.
[0079] The different damping characteristics of the inner base
element and the outer base element support a desirable use of the
stool: The inner base element allows small, high-frequency
movements of a user, which stimulates the user's muscular system.
The user may constantly make micro-adjustments to her position on
the stool while maintain balance, and thereby exercising her
muscles. Intentional larger movements of the stool, i.e. larger
pivot angles when reaching for a distant object, are possible and
supported by deformation of the outer base element. However, such
larger movements are significantly more dampened than small and
fast movements. This provides a sense of stability to the user and
avoids a risk of accidental fall.
[0080] FIG. 11 illustrates this general concept of the base 3
schematically. The body structure 4 can pivot relative to the floor
in response to a lateral force F by resiliently deforming the inner
base element 20 or the outer base element 10. Each of the base
elements is a mechanical spring damper system. The inner base
element is preferably underdamped, i.e. its damping ratio is
smaller than one. The outer base element is preferably overdamped,
i.e. its damping ratio is greater than one. The stool 1 so achieves
a dynamic behavior that previously could only be accomplished with
pressurized components, but without using any such pressurized
components.
[0081] As shown in FIG. 11, the seat 2 may be pivotably mounted to
an upper end of the body structure 4. The seat 2 may include an
upper seat member 111 which is firmly attached to a lower seat
member 112. The connection between the upper seat member 111 and
the lower seat member 112 resembles the connection between the
inner base element 20 and the outer base element 10. The lower seat
member 112 may be made of a resiliently deformable material. The
lower seat member 112 may be a radially or diagonally slotted
spring steel disk, which may be identical to the inner base element
20. When in use, the seat 2 may move horizontally in any direction
while staying in a generally horizontal orientation. That is, while
the body structure 4 pivots about the base 3, the seat 2 can pivot
in opposite direction relative to the body structure and thereby
maintain a generally horizontal orientation.
[0082] FIG. 13 shows a configuration of a resiliently deformable
inner base element 20 having a frustoconical lower surface 131
which faces a correspondingly shaped conical surface of an
adjustment member 132. The adjustment member 132 is
height-adjustably attached to the body structure 4. The adjustment
member 132 limits how far the inner base element 20 can deform
downwardly. Deformation of the inner base element 20 is limited to
an adjustment space 133 between the inner base element 20 and the
adjustment member 132. The adjustment member is arranged within the
outer base element 10 and below the inner base element 20.
[0083] An alternative configuration of an adjustment member 142 is
shown in FIG. 14. Here, the resiliently deformable inner base
element 20 has a frustoconical upper surface 141 which faces a
correspondingly shaped conical surface of an adjustment member 142.
In this configuration the upward movement of the inner base element
20 is upwardly limited to a space 143 above the inner base element
20 and below the adjustment member 142. As indicated by dotted
lines the position of the adjustment member 142 can be
adjusted.
[0084] A differently configured stool is shown in FIG. 15-17. The
tiltable stool 1 has a base 3 and an elongated body structure 4
between the base 3 and a seat 2. The base 3 includes an upper base
element 150 which is firmly connected to a lower base element 160.
The body structure 4 is firmly connected to a central portion 29 of
the upper base element 150. The central portion 29 includes a
receiving opening for a lower portion of the body structure 4. The
lower base element 160 is configured to rest on a floor.
[0085] The upper base element 150 is resiliently deformable. The
lower base element 160 may be resiliently deformable and may in
particular be the annular elastic base disclosed in the applicant's
U.S. Pat. No. 9,894,998. The lower base element 160 may however be
inelastic and may e.g. include roller wheels 281 attached to a
rigid support structure 282 as shown in FIG. 28. At least the
resiliently deformable upper base element 150 allows the body
structure 4 to pivot in any direction. Even more preferably, both
the upper base element 150 and the lower base element 160 are
resiliently deformable and complement each other with different
frequency responses to a deflective force.
[0086] When a tilting force is applied to the seat, the seat is
moved from a normal position as illustrated in FIG. 16 into a
dynamic seating position as shown in FIG. 15. Tiltability of the
upper base element is enhanced by an annular groove 151 which is
arranged concentrically around and proximal to the central portion
29. The annular groove may have a generally V-shaped profile with
an inner side wall 153 and an outer side wall 152. Both side walls
152, 153 extend from an upper end of the groove to a bottom 154 of
the groove 151. The inner side wall 153 and the outer side wall 152
may be slanted at an angle towards one another. This causes a
downwardly diminishing width of the groove. The bottom 154 of the
groove may be generally flat.
[0087] The annular groove 151 is relatively deep, i.e. a depth of
the groove is greater than a width of the groove. As illustrated,
the groove is about three times deeper than it is wide.
[0088] The annular groove 151 allows use of relatively hard
materials having a hardness greater than 90 Shore. Elasticity is
primarily achieved through the shape of the groove, not the
softness of the material used. Use of a relatively hard material is
desirable, especially when using TPU which tends to become harder
and brittle over time. This is true especially in areas where the
TPU is frequently deformed. The structural elasticity afforded by
the annular groove provides a longer life than elasticity obtained
from use of softer material.
[0089] A tilt angle adjustment ring 170 may be provided. The tilt
angle adjustment ring 170 as shown in FIG. 17 is axially
displaceable along the longitudinal axis of the body structure 4.
For example, a lower portion of the body structure 4 may have an
outer thread 171 which meshes with an inner thread 172 of the
adjustment ring. The axial position of the adjustment ring 170 can
then be selected by rotating the adjustment ring relative to the
body structure 4.
[0090] A lower portion 173 of the adjustment ring is configured to
engage the annular groove 151 at a selectable depth. In a lowermost
position of the adjustment ring 170 the lower portion 173 protrudes
completely into and fills the space within the groove 151. Thereby,
the deformability of the upper base member 150 in the area of the
groove 151 is substantially reduced.
[0091] By raising the adjustment ring, a maximum tilt angle .alpha.
of the stool can be controlled. The stool can tilt only until the
upper end of the outer wall 152 touches the lower portion 173 of
the adjustment ring 170.
[0092] The lower base element 160 is arranged entirely below and
firmly connected to the upper base element 150. In particular, an
upper annular end of the lower base element is connected to an
outer end of the upper base element. The upper base element 150 may
be connected to the lower base element 160 by a tongue and groove
joint. As shown in FIGS. 15-17, the lower base element 160 may
include an upwardly facing tongue 161 which engages a downwardly
open groove 155 in the outer end of the upper base element 150.
[0093] The upper base element 150 and the lower base element 160
preferably transition seamlessly, i.e. smoothly and without gaps,
into one another.
[0094] An alternative configuration of an upper base element 180 is
shown in FIGS. 18-20 and FIG. 24. The upper base element 180 has
two radially spaced concentric grooves 181,182. This includes an
outer groove 181 and an inner groove 182. In the illustrated
configuration the grooves 181,182 have a generally U-shaped profile
with parallel side walls. The side walls include an outer side wall
183 and a parallel inner side wall 184. The U-shaped profile of the
grooves 181,182 allows the body structure 4 to pivot in any
direction about a pivot point P. The pivot point P is arranged
along a central axis of the upper base element 180 within the
base.
[0095] A total width of upper ends of the inner groove 182 and the
outer groove 181 determines a maximum tilt angle .alpha. of the
body structure 4 relative to the base 3. As shown in FIGS. 18 and
19, the maximum tilt angle .alpha. is reached when the grooves
181,182 have been fully deformed such that upper ends of their
respective inner side walls 184 and outer side walls 183 touch. The
maximum tilt angle .alpha. is preferably about 10 degrees.
[0096] The width of the grooves 181,182 should be selected to meet
pinch test standards and is preferably less than 8 mm or wider than
23 mm. The grooves 181, 182 may be filled with a compressible
material 185, for example a rubber compound.
[0097] Alternatively, the grooves 181, 182 may be covered with an
annular cover 251 as shown in FIG. 25. The annular cover 251 is
made of a compressible material such as a rubber compound or a
resiliently deformable foam. The annular cover may have a
ring-shaped body 254 which extends from the inner wall of the
innermost groove to the outer wall of the outermost groove.
Thereby, the ring-shaped body 254 covers upper ends of the grooves
181, 182. Extending downwardly from the ring-shaped body 254 are
legs 252, 253 which extend into the grooves 181, 182. The legs 252,
253 may be held in the grooves 181, 182 by a form-fit
connection.
[0098] Stiffening ribs 186, 187 may be formed in the upper base
element 180 radially outwardly of the grooves 181,182. Thereby,
resilient deformation of the upper base element 180 is
substantially limited to the area of the grooves 181,182.
[0099] Another alternative configuration of an upper base element
210 is shown in FIGS. 21-23. In this configuration, five radially
spaced grooves 211-215 are used. The grooves 211-215 are relatively
shallow and resemble corrugations. The grooves 211-215 have a
generally sinusoidal profile of alternating ridges and valleys.
Relatively shallow here refers to a depth of the grooves being
smaller than a width of the grooves. The corrugated profile of the
upper base element 210 extends substantially along its entire
surface from its center 216 to its radially outer end 217.
[0100] Irrespective of a particular embodiment, the upper base
element 150,180,210 is preferably an integrally molded single
piece. In combination with a single-piece molded lower base element
160 the base 3 may thus consist essentially of only two parts. This
allows for very cost effective manufacturing yet provides a
desirable dynamic deformation. The utilization of grooves has
proven beneficial to extend the useful life of the base.
[0101] In some configurations, it may be desirable not form the
upper base element as a single part, but rather as an assembly of
several pieces. One example of such a modular design is shown in
FIG. 26. As shown, the body structure 4 of the stool is held in an
inner base body 261. The inner base body is connected to an
intermediate upper base body 260. The intermediate upper base body
260 is a resiliently deformable molded component. The intermediate
upper base body 260 includes annual grooves 181, 182 which allows
the body structure 4 to pivot in any direction. The intermediate
upper base body 260 may overlap the inner base body 261 and extend
to the body structure 4. That is, the inner base body 261 may be
covered entirely by the intermediate upper base body 260. The
intermediate upper base body 260 may be connected to the inner base
body 261 with fasteners 265. An outer upper base body 262 may be
arranged around the intermediate upper base body 260. The outer
upper base body 262 may be generally disk-shaped and extend
radially from the intermediate upper base body 260 at its inner end
to a lower base body 263 at its outer end.
[0102] FIG. 27 shows an alternative configuration of an
intermediate upper base body 270. As shown, the intermediate upper
base body 270 is connected to the inner base body by an inner
tongue-and-groove joint 272. The intermediate upper base body 270
is connected to the outer upper base body 275 by an outer
tongue-and-groove joint 273. The intermediate upper base body 270
is covered by a cover 271 which reaches above the annular grooves
formed in the intermediate upper base body 270. The cover 271
extends from the inner base body 261 to the outer upper base body
275. The cover 271 provides a seamlessly surface which hides the
intermediate upper base body 270.
[0103] FIG. 29 shows a stool with a resiliently deformable base
having an upper base member 292 which includes a plurality of two
or more annual grooves 293. The grooves 293 are configured to
deform under lateral load which allows the body structure 4 to
pivot relative to the floor. The seat 2 is pivotably mounted to an
upper end of the body structure 4. The seat 2 includes an upper
seat member 111 which is firmly attached to a lower seat member
112. The lower seat member 112 mirrors the design of the upper base
member 292 in that it has a plurality of two or more grooves 294.
This allows the seat 2 to pivot relative to the body structure 4.
The lower seat member 112 and the upper base member 292 may be so
similar that they can be molded from a common tool.
[0104] Desirable configurations of a tiltable stool include: A
tiltable stool, comprising: a seat; an inner base element; a body
structure extending between the seat and the inner base element,
the body structure being firmly connected to a central portion of
the inner base element; and an outer base element, the outer base
element having an annular upper end extending outwardly around the
inner base element and a rotationally symmetrical outwardly convex
and inwardly concave body extending from the annular upper end to
an annular lower end, wherein the outer base element or the inner
base element is resiliently deformable, thereby allowing the body
structure to pivot in any direction.
[0105] The tiltable stool as described above, wherein the outer
base element and the inner base element are connected to each other
with a tongue and groove joint.
[0106] The tiltable stool as described above, wherein the outer
base element comprises an inwardly facing tongue which engaged an
outwardly open groove in the inner base element.
[0107] The tiltable stool as described above, wherein an upper
surface of the inner base element and an upper surface of the outer
base element are arranged in a common plane.
[0108] The tiltable stool as described above, wherein an upper
surface of the inner base element and an upper surface of the outer
base element transition seamlessly into one another.
[0109] The tiltable stool as described above, wherein the inner
base element comprises an outwardly facing cylindrical support
surface which abuts a corresponding inwardly facing cylindrical
support surface of the outer base element.
[0110] The tiltable stool as described above, wherein the outer
base element comprises an inwardly facing tongue which engaged an
outwardly open groove in the inner base element, and wherein the
outwardly facing cylindrical support surface of the inner base
element is arranged above the groove and the inwardly facing
cylindrical support surface of the outer base element is arranged
above the tongue.
[0111] The tiltable stool as described above, wherein the inner
base element is made of an inelastic material and the outer base
element is made of a resiliently deformable material.
[0112] The tiltable stool as described above, wherein the inner
base element is made of a resiliently deformable material and the
outer base element is made of an inelastic material.
[0113] The tiltable stool as described above, wherein both the
inner base element and the outer base element are made of
resiliently deformable material.
[0114] The tiltable stool as described above, further comprising an
adjustment disk which is arranged at a variable height below the
inner base element.
[0115] The tiltable stool as described above, wherein a maximum
tilt angle of the body structure is limited by selecting the
variable height of the adjustment disk below the inner base
element.
[0116] The tiltable stool as described above, wherein the body
structure extends through the inner base element and wherein the
adjustment disk comprises an inner thread which engages a
corresponding outer thread arranged at a lower end of the body
structure.
[0117] The tiltable stool as described above, the adjustment disk
is configured to push against the outer base element when a maximum
tilt angle of the body structure has been reached.
[0118] The tiltable stool as described above, wherein the outer
base element has a generally C-shaped cross section.
[0119] The tiltable stool as described above, wherein the inner
base element is generally disk-shaped.
[0120] The tiltable stool as described above, wherein the inner
base element comprises a plurality of circumferentially distributed
slots extending outward away from the central portion.
[0121] The tiltable stool as described above, wherein the seat is
pivotally mounted to an upper end of the body structure.
[0122] A tiltable stool, comprising: a seat; a resiliently
deformable inner base element; a body structure extending between
the seat and the inner base element, the body structure being
firmly connected to a central portion of the inner base element;
and a resiliently deformable outer base element extending outwardly
around the inner base element, wherein the inner base element and
the outer base element each form a spring damper system, allowing
the body structure to pivot in any direction by deforming the inner
base element and the outer base element.
[0123] The tiltable stool as described above, wherein a damping
factor of the outer base element is larger than a damping factor of
the inner base element.
[0124] Various configurations of a tiltable stool are possible by
combining any two or more of the following features: The structure
of the lower base element being a rotationally symmetrical
outwardly convex and inwardly concave body extending from the
annular upper end to an annular lower end. The lower base element
and the upper base element being connected to each other with a
tongue and groove joint, in particular the lower base element
having an upwardly facing tongue which engages a downwardly open
groove in the upper base element. A seamless transition of an outer
surface of the upper base element and an outer surface of the lower
base element. A material selection of the upper base element being
made of a resiliently deformable material and the lower base
element being made of an inelastic material, or alternatively both
the upper base element and the lower base element being made of
resiliently deformable material. The upper base element having an
annular groove, in particular an annular groove that is deeper than
it is wide. The specific structure of the annular groove having an
inner side wall and an outer side wall, the inner side wall and the
outer side wall being arranged at an angle towards one another when
the tiltable stool is in an upright position. The position of the
annular groove being arranged concentrically around and proximal to
the central portion. The shape of the annular groove having a
generally V-shaped cross-sectional profile with a flat bottom. The
limitation of a maximum tilt angle when the upper portions of an
inner side wall and outer side wall of an annular groove touch. The
use of a tilt angle adjustment ring which is axially displaceable
along a longitudinal axis of the body structure in which the tilt
angle adjustment ring has a lower portion which engages the annular
groove at a selectable depth. A maximum tilt angle of the body
structure being limited by selecting the selectable depth of the
lower portion of the tilt angle adjustment ring in the annular
groove. The upper base element having a plurality of concentric and
radially spaced annular grooves, in particular grooves having a
generally U-shaped cross-sectional profile. Annular grooves being
filled with a compressible compound or covered by a cover. The
annular grooves being wider than they are deep. The upper base
element being generally disk-shaped.
[0125] One skilled in the art will recognize that various
additional configurations can be achieved by adding features not
specifically listed above but generally described in this
specification.
[0126] Within this specification the words "example" and
"exemplary" are used herein to mean serving as an instance or
illustration. Any embodiment or design described herein as
"example" or "exemplary" is not necessarily to be construed as
preferred or advantageous over other embodiments or designs.
Rather, use of the word example or exemplary is intended to present
concepts in a concrete fashion. As used in this application and the
following claims the term "or" is an inclusive "or" rather than an
exclusive "or". That is, "or" means "and/or" unless specified
otherwise or clear from context. The articles "a" and "an" as used
in this application and the appended claims should generally be
construed to mean "one or more" unless specified otherwise or clear
from context to be directed to a singular form.
* * * * *