U.S. patent application number 11/094310 was filed with the patent office on 2005-08-04 for auditorium seating.
Invention is credited to Pernicka, Vaclav, Shats, Michael.
Application Number | 20050168017 11/094310 |
Document ID | / |
Family ID | 34436130 |
Filed Date | 2005-08-04 |
United States Patent
Application |
20050168017 |
Kind Code |
A1 |
Pernicka, Vaclav ; et
al. |
August 4, 2005 |
Auditorium seating
Abstract
A seating apparatus includes a support element having an upright
extending from a floor and a swing arm pivotably mounted to the
upright about a generally vertical pivot axis, a work surface is
secured to the upright above the swing arm, and a seat is mounted
on the swing arm, and the seat having a seat base upon which an
occupant can be seated. The swing arm is pivotable between a stowed
position wherein the seat base is tucked substantially underneath
the work surface, and a deployed position wherein the seat base is
substantially clear of the work surface. The seating apparatus
further includes a dynamic return stop element secured to the swing
arm and a static return stop element secured to the upright. The
dynamic and static return stop elements are positioned in a common
horizontal plane and abut each other when the swing arm is in the
stowed position. At least one of the static and dynamic return stop
elements is adjustable relative to the swing arm and the upright,
respectively, to change the angular position of the swing arm
relative to the upright when the swing arm is in the stowed
position.
Inventors: |
Pernicka, Vaclav; (Brampton,
CA) ; Shats, Michael; (Thornhill, CA) |
Correspondence
Address: |
BERESKIN AND PARR
40 KING STREET WEST
BOX 401
TORONTO
ON
M5H 3Y2
CA
|
Family ID: |
34436130 |
Appl. No.: |
11/094310 |
Filed: |
March 31, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11094310 |
Mar 31, 2005 |
|
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|
10651239 |
Aug 29, 2003 |
|
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|
6899385 |
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Current U.S.
Class: |
297/142 |
Current CPC
Class: |
A47C 1/12 20130101; A47B
83/02 20130101; A47C 9/022 20130101; A47C 7/002 20130101 |
Class at
Publication: |
297/142 |
International
Class: |
A47B 083/02 |
Claims
1. A seating apparatus comprising: a) a support element having an
upright extending from a floor and a swing arm pivotably mounted to
the upright about a generally vertical pivot axis; b) a work
surface secured to the upright above the swing arm; c) a seat
mounted on the swing arm, the seat having a seat base upon which an
occupant can be seated; d) the swing arm being pivotable between a
stowed position wherein the seat base is tucked substantially
underneath the work surface, and a deployed position wherein the
seat base is substantially clear of the work surface; and e) a
dynamic return stop element secured to the swing arm and a static
return stop element secured to the upright, the dynamic and static
return stop elements positioned in a common horizontal plane and
abutting each other when the swing arm is in the stowed position,
at least one of the static and dynamic return stop elements being
adjustable relative to the swing arm and the upright, respectively,
to change the angular position of the swing arm relative to the
upright when the swing arm is in the stowed position.
2. The apparatus of claim 1 wherein the dynamic return stop element
is adjustable relative to the swing arm to which the dynamic return
stop element is secured.
3. The apparatus of claim 2 wherein the dynamic return stop element
comprises an eccentrically mounted button, the button having an
attachment axis about which the button can be rotatably adjusted,
and an outer surface spaced laterally away from the attachment axis
for contacting the static return stop element.
4. The apparatus of claim 3 wherein the static return stop element
comprises a bracket extending from the upright.
5. The apparatus of claim 4 wherein the bracket has at least one
generally vertical gusset, and the static return stop element
comprises an exposed edge of the gusset.
6. The apparatus of claim 1 further comprising biasing means for
biasing the arm to the stowed position.
7. The apparatus of claim 6 wherein the biasing means comprises a
flat coiled torsion spring, the torsion spring having a first end
fixed directly or indirectly to the upright and a second end fixed
directly or indirectly to the swing arm.
8. The apparatus of claim 7 wherein the flat coiled torsion spring
comprises a thin strip of resilient metal coiled in a flat spiral
about the pivot axis.
9. A seating apparatus comprising: a) a support element having an
upright extending from a floor and a swing arm pivotably mounted to
the upright about a pivot joint having generally vertical pivot
axis; b) a work surface secured to the upright above the swing arm;
c) a seat mounted on the swing arm, the seat having a seat base
upon which an occupant can be seated; d) the swing arm being
pivotable between a stowed position wherein the seat base is tucked
substantially underneath the work surface, and a deployed position
wherein the seat base is substantially clear of the work surface;
and e) the upright having a lower end adjacent the floor and an
upper end adjacent the work surface, the upright being generally
straight, and inclined to the vertical such that, relative to a
direction in which the seating apparatus is facing, the upper end
of the upright is forward of the pivot joint, and the pivot joint
is forward of the lower end of the upright.
10. The apparatus according to claim 9 wherein the lower end of the
upright provides an attachment locus for attachment of the upright
to the floor, the attachment locus being positioned rearward of the
pivot axis.
11. The apparatus according to claim 10 wherein the attachment
locus of the upright is rearward of a leading edge of the seat base
when the swing arm is in the deployed position.
12. The apparatus according to claim 9 wherein the upright is free
of bends between the lower end and the upper end of the
upright.
13. The apparatus according to claim 12 wherein the pivot axis is
inclined relative to the axis of the upright.
14. The apparatus according to claim 9 wherein the upright has a
lower end face that is generally perpendicular to the axis of the
upright.
15. The apparatus according to claim 14 further comprising a floor
bracket secured to the lower end of the upright for mounting the
apparatus to the floor.
16. The apparatus according to claim 15 wherein the floor bracket
comprises a flange adapted to be mounted in flush engagement to the
floor and an attachment pocket positioned generally centrally of
the flange and in elevation above the flange, the attachment pocket
adapted to receive the lower end of the upright.
17. The apparatus according to claim 16 wherein the attachment
pocket has an inclined base that is adapted to engage the lower end
face of the upright in flush engagement.
18. The apparatus according to claim 14 wherein the upright has an
upper end face that is generally perpendicular to the axis of the
upright.
19. A swivel mechanism for swivelably supporting a seat above an
arm, the mechanism comprises: a) a sleeve fixed to an outer end of
the arm, the sleeve having open upper and lower ends; b) a post
rotatable within the sleeve, the post having an upper end for
attachment to a seat, the post being axially moveable between a
raised position and a lowered position; c) an upper cam fixed
within the sleeve and a lower cam fixed to the post and slidable
within the sleeve, the upper cam disposed between the lower cam and
the upper end of the post; the upper and lower cams having matching
inclined annular lower and upper surfaces, respectively, wherein
the position of the lower cam relative to the upper cam providing
generally flush contact of the matching inclined annular surfaces
defines the central position of the swivel mechanism; and d) a
compression spring urging the lower cam against the upper cam,
thereby urging the post to the raised position and the swivel
mechanism to the central position.
20. The swivel mechanism of claim 18 wherein the upper cam has at
least one downwardly directed crest and the lower cam has at least
one upwardly directed crest, and wherein, when the pivot is in the
lowered position, an axial gap is provided between the downwardly
directed and upwardly directed events.
Description
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 10/651,239, entitled "Auditorium Seating",
which was filed on Aug. 29, 2003, and the entire contents of which
is also hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates to a seating apparatus for use in
auditoriums, lecture halls, cafeterias, meeting rooms, and the
like.
BACKGROUND OF THE INVENTION
[0003] Seating systems that provide seating with attached desks or
work surfaces are often convenient for use in lecture halls,
classrooms, meeting rooms, or similar facilities. Some existing
seating systems of this type have desks or work surfaces supported
above a floor by structural support elements. Seats are attached to
the support elements by a pivot arm extending from the support
element, so that the seat can be stowed under the desk when not in
use.
[0004] It is known to include biasing means in these seating
systems to bias the swing arm to the stowed position. The biasing
means in known seating systems comprises a tension spring having
one end fixed to the structural member, and the other end fixed at
a point along the length of the arm. The tension springs can be
difficult to install, and generally remain exposed so that they are
prone to damage and/or premature wear.
[0005] Furthermore, in known seating systems having seats attached
to pivot arms, the angular position of the pivot arm relative to
the structural member defining the stowed position is not
adjustable once the seating system has been manufactured and
assembled. Accordingly, due to variations in the manufacturing and
assembly of the seating systems, adjacent seats in a row of seating
may not have uniform stowed positions. In other words, some seats
may be spaced away from the work surface when in the stowed
position, while other seats may touch the work surface when in the
stowed position. An excessive gap between the seat and the desk
when in the stowed position can obstruct aisles between adjacent
rows of seats. Having no space at all between the seat and the desk
when in the stowed position can cause wear or damage to the seat
and the desk. As well, seats having different spacings between the
seats and the desk when in the stowed position can create an untidy
appearance.
[0006] With respect to the structural members of the known seating
systems, uprights having a vertical lower portion and an inclined
upper portion are generally used to support the work surface above
the floor. The upper and lower portions of the uprights are
typically constructed of square or rectangular steel channel, with
a welded joint provided between the upper and lower portions.
Accordingly, the uprights can be rather costly.
[0007] It is also known in existing seating systems to provide a
swivel joint between the chair and the pivot arm to which it is
attached. Providing an auto-orientation feature whereby the seat is
biased towards the forward direction is also a known feature.
Examples of existing swivel joints comprise dual inner and outer
compression springs, thrust bearings, and co-operating cam
surfaces. These joints are rather complex and can be costly to
produce.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide an
improved seating apparatus and elements of a seating system
suitable for use in, lecture halls, classrooms, cafeterias, meeting
rooms, and the like.
[0009] According to one aspect of the present invention, a seating
apparatus has a support element having an upright extending from a
floor and a swing arm pivotably mounted to the upright about a
generally vertical pivot axis. The seating apparatus is further
provided with a work surface secured to the upright above the swing
arm, and a seat mounted on the swing arm, the seat having a seat
base upon which an occupant can be seated. The swing arm is
pivotable between a stowed position wherein the seat base is tucked
substantially underneath the work surface, and a deployed position
wherein the seat base is substantially clear of the work surface.
The seating apparatus is also provided with a flat coiled torsion
spring for biasing the arm to the stowed position, the torsion
spring having a first end fixed directly or indirectly to the
upright and a second end fixed directly or indirectly to the swing
arm.
[0010] The flat coiled torsion spring can be of a thin strip of
resilient metal coiled in a flat spiral about the pivot axis. The
arm can be pivotable about a pivot joint having upper and lower
brackets extending from the upright to vertically straddle an inner
end of the arm, a bore provided in the straddled inner end of the
arm, and a generally vertical pin supported by the brackets and
extending through the bore of the arm, the arm being pivotable
about the pin.
[0011] The seating apparatus can be provided with a boss fixed to
pivot with the arm, the boss extending axially between the arm and
an adjacent one of the upper and lower brackets of the pivot joint.
The pivot joint can include a bushing provided in the bore, the
bushing having an outer surface sized to fit snugly within an inner
surface of the bore, and an inner diameter sized to provide a
sliding fit with the pin. The boss can extend from the bushing.
[0012] The seating apparatus can further include anti-rotate means
adjacent the bushing and the bore for preventing relative motion
between the bushing and bore. The anti-rotate means can include an
axial groove along the outer surface of the bushing and a radially
inwardly directed key extending from the inner surface of the bore
and engaging the groove of the bushing.
[0013] The second end of the torsion spring can be fixed to the
boss, and the first end of the torsion spring can be fixed to the
adjacent one of the upper and lower brackets of the pivot joint.
The adjacent one of the upper and lower brackets can have a
generally vertical gusset with an exposed edge extending adjacent
the boss.
[0014] 11. The apparatus of claim 10 wherein the first end of the
torsion spring comprises a radially outwardly extending hook that
is hooked onto the exposed edge of the gusset. The boss can extend
axially through the center of the torsion spring, and the second
end of the torsion spring can have a tab directed radially
inwardly, and the boss can have a transverse slot to engage the
tab.
[0015] The seating apparatus can further be provided with a swivel
mechanism for swivelably supporting the seat above the swing arm,
the swivel mechanism biasing the seat in a central direction. The
swivel mechanism can have a sleeve fixed to an outer end of the
swing arm, the sleeve having open upper and lower ends, a post
rotatable within the sleeve, the post having an upper end for
attachment to a seat, an upper cam fixed within the sleeve and a
lower cam fixed to the post and slidable within the sleeve. The
upper cam can be disposed between the lower cam and the upper end
of the post, and the upper and lower cams can have matching
inclined annular lower and upper surfaces, respectively. The
position of the lower cam relative to the upper cam that provides
generally flush contact of the matching inclined annular surfaces
defines the central position of the swivel mechanism. The swivel
mechanism can also have a compression spring urging the lower cam
against the upper cam.
[0016] According to a second aspect of the invention, a support
element for a seating apparatus has an upright for supporting a
work surface above a floor. A swing arm for supporting a seat is
pivotably mounted to the upright and pivotable between a stowed
position wherein a seat supported by the swing arm is substantially
underneath a work surface supported by the upright, and a deployed
position wherein a seat supported by the swing arm is substantially
clear of a work surface supported by the upright. A flat coiled
torsion spring is provided for biasing the arm to the stowed
position, the torsion spring having a first end fixed directly or
indirectly to the upright and a second end fixed directly or
indirectly to the swing arm.
[0017] According to a third aspect of the invention, a seating
apparatus has a support element having an upright extending from a
floor and a swing arm pivotably mounted to the upright about a
generally vertical pivot axis. A work surface is secured to the
upright above the swing arm. A seat is mounted on the swing arm,
the seat having a seat base upon which an occupant can be seated.
The swing arm is pivotable between a stowed position wherein the
seat base is tucked substantially underneath the work surface, and
a deployed position wherein the seat base is substantially clear of
the work surface. A dynamic return stop element is secured to the
arm and a static return stop element is secured to the upright, the
dynamic and static return stop elements positioned in a common
horizontal plane and abutting each other when the arm is in the
stowed position. At least one of the static and dynamic return stop
elements is adjustable to change the angular position of the arm
relative to the upright corresponding to the position at which the
dynamic and static return stop elements abut.
[0018] The dynamic return stop element can include an eccentrically
mounted button, the button having an attachment axis about which
the button can be rotatably adjusted, and an outer surface spaced
laterally away from the attachment axis for contacting the static
return stop element. The static return stop element can include a
bracket extending from the upright. The bracket can have at least
one generally vertical gusset, and the static return stop element
can include an exposed edge of the gusset.
[0019] The seating apparatus according to the third aspect of the
invention can further be provided with biasing means for biasing
the arm to the stowed position. The biasing means can include a
flat coiled torsion spring, the torsion spring having a first end
fixed directly or indirectly to the upright and a second end fixed
directly or indirectly to the swing arm.
[0020] According to a fourth aspect of the invention, a seating
apparatus has a support element having an upright extending from a
floor and a swing arm pivotably mounted to the upright about a
generally vertical pivot axis. A work surface is secured to the
upright above the swing arm. A seat is mounted on the swing arm,
the seat having a seat base upon which an occupant can be seated.
The swing arm is pivotable between a stowed position wherein the
seat base is tucked substantially underneath the work surface, and
a deployed position wherein the seat base is substantially clear of
the work surface. The upright is generally straight, and inclined
to the vertical such that, relative to a direction in which the
seating apparatus is facing, the upper end of the upright is
forward of the pivot joint, and the pivot joint is forward of the
lower end of the upright.
[0021] The upright can have upper and lower ends that are generally
perpendicular to the axis of the uprights. A work surface mounting
bracket can be provided adjacent the upper end of the upright for
mounting the work surface obliquely with respect to the generally
perpendicular upper end of the upright.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] For a better understanding of the present invention and to
show more clearly how it may be carried into effect, reference will
now be made by way of example, to the accompanying drawings that
show embodiments of the present invention, and in which:
[0023] FIG. 1 is a perspective view of one embodiment of a seating
apparatus according to the present invention;
[0024] FIG. 2 is a side view of the apparatus of FIG. 1;
[0025] FIG. 3 is a top view of two rows of the seating apparatus of
FIG. 1;
[0026] FIG. 4 is an enlarged perspective view of a portion of the
apparatus of FIG. 1;
[0027] FIG. 5 is an exploded view of the portion of the apparatus
of FIG. 1 shown in FIG. 4;
[0028] FIGS. 6a, 6b and 6c are bottom views of a portion of the
apparatus of FIG. 4 showing an arm in intermediate, deployed, and
stowed positions, respectively;
[0029] FIG. 7 is an enlarged perspective view of another portion of
the apparatus of FIG. 1;
[0030] FIG. 8 is an exploded view of a portion of the apparatus of
FIG. 3;
[0031] FIGS. 8a and 8b are perspective views of the upper and lower
cams, respectively, of FIG. 8;
[0032] FIGS. 9 and 10 are side sectional views of the portion of
the apparatus of FIG. 8 shown in a forward and in a sideways
oriented position, respectively;
[0033] FIG. 11 is an enlarged side view showing further details of
the apparatus of FIG. 2;
[0034] FIG. 12 is an enlarged side view of the apparatus of FIG. 1
adapted to be mounted on an inclined floor;
[0035] FIGS. 12a and 12b are enlarged exploded views showing a
lower portion of the apparatus of FIG. 12 in greater detail;
[0036] FIG. 13 is an exploded perspective view showing an alternate
embodiment of a swivel mechanism according to the present
invention;
[0037] FIG. 13a is a perspective view of an upper cam element of
the mechanism of FIG. 13;
[0038] FIG. 13b is a perspective view of a lower cam element of the
mechanism of FIG. 13;
[0039] FIG. 14 is an enlarged elevation view in cross-section of a
housing portion of the mechanism of FIG. 13; and
[0040] FIGS. 15 and 16 are side sectional views of the mechanism of
FIG. 13 shown in a forward and in a sideways oriented position,
respectively.
DETAILED DESCRIPTION OF THE INVENTION
[0041] A seating apparatus according to the present invention is
shown generally at 100 in the Figures. Referring to FIGS. 1 and 2,
the apparatus 100 has at least one support element 102 for
supporting a seat 104 and a work surface 106 above a floor 108.
[0042] The seats 104 can have a seat base 110 and a backrest 112.
The work surface 106 can be a panel constructed of high pressure
laminate. The work surface 106 presents an adjacent edge 114 that
faces the backrests 112 of the seats 104.
[0043] Each support element 102 comprises an upright 116 and at
least one swing arm 120 pivotably mounted to the upright 116. Each
swing arm 120 has an inner end 122 and an outer end 124. The inner
end 122 of the swing arm 120 is pivotably attached to the upright
116 by means of a pivot joint 125. The outer ends 124 of the swing
arms 120 support the seats 104.
[0044] The swing arms 120 are pivotable between stowed positions,
identified at 126 (in phantom line) in FIG. 2, and deployed
positions, identified at 128 (in solid line) in FIG. 2. In the
stowed position 126, the seat bases 110 of the seats 104 are tucked
substantially underneath the work surface 106. In the deployed
position 128, the seat bases 110 of the seats 104 are substantially
clear of the work surface 106 a sufficient extent so that a user
(not shown) can enter, exit, and sit in the seat 104.
[0045] Furthermore, when the arm 120 is in the stowed position 126,
the backrest 112 of the seat 104 either abuts the adjacent edge 114
of the work surface 106, or is spaced away from the adjacent edge
114 by a relatively narrow gap 130 (as illustrated in FIG. 2). When
in the deployed position 128, a relatively large access space 132
is provided between the backrest 112 of the seat 104 and the
adjacent edge 114 of the work surface 106, again allowing a user to
enter, exit, and sit in the seat 104.
[0046] Providing the seat base 110 of the seat 104 in a position
clear of the work surface 106, and providing the access space 132
between the backrest 112 of the seat 104 and the adjacent edge 114
of the work surface 106, can facilitate entry and exit of an
occupant of the seat 104. Returning the seat 104 to the stowed
position 126 can provide improved passage behind the seats 104,
such as in aisles 134 between adjacent rows of the seating
apparatus 100 (FIG. 3).
[0047] In the embodiment illustrated, three support elements 102
are used to support an elongate work surface 106, providing a
single row of four seats 104. As best seen in FIG. 3, with respect
to a forward facing direction indicated by arrow 135, the three
support elements 102 include a left, a right, and a center support
element 102a, 102b and 102c, respectively.
[0048] The left support element 102a has an upright 116a with a
single arm 120a extending to the right of the upright 116a. The arm
120a rotates clockwise (when viewed from above) to pivot from the
stowed position to the deployed position.
[0049] The right support element 102b has an upright 116b with a
single arm 120b extending to the left of the upright 116b. The arm
120b rotates counter-clockwise (when viewed from above) to pivot
from the stowed position to the deployed position. The center
support element 102 has an upright 116c with two arms 120, namely
one arm 120a and one arm 120b, extending to the left and right,
respectively, of the upright 116c.
[0050] Although three distinct support elements 102a, 102b, and
102c are included in the apparatus 100, it will be readily
understood that the corresponding uprights 116 and arms 120 are
similar in construction, having elements that are identical or
simply mirror images of each other. Accordingly, in the following
description, references to a generic support element 102, upright
116, and arm 120 pertain to any one of the three support elements
102a, 102b, 102c, the three uprights 116a, 116b, 116c, and the two
arms 102a, 102b. For clarity, the positions of the support element
102 shown in FIG. 4 (and following) are of a left support element
102a.
[0051] Referring now to FIG. 4, the pivot joint 125 of the support
element 102 provides a generally vertical pivot axis 151 about
which the arm 120 can pivot. In the embodiment illustrated, the
pivot joint 125 comprises a stationary portion 150a fixed to the
upright 102, and a pivoting portion 150b fixed to the arm 120.
[0052] As best seen in FIG. 5, the stationary portion 150a of the
pivot joint 125 has upper and lower pivot joint brackets 152, 154,
respectively, that extend from the upright 116. The brackets
152,154 are spaced apart along the length of the upright 116 to
vertically straddle the inner end 122 of the arm 120. The upper
pivot joint bracket 152 and lower pivot joint bracket 154 have
opposed upper and lower horizontal plates 156 and 158,
respectively. Vertically aligned upper and lower apertures 162, 164
are provided in the upper and lower plates 156, 158, respectively.
An elongate pin 160 extends through the apertures 162, 164 and is
secured with a washer 161 and a nut 163 threaded on to the lower
portion of the pin 160. The axis of the pin 160 corresponds to the
pivot axis 151 about which the arm 120 can pivot.
[0053] In the illustrated embodiment, as best seen in FIG. 5, the
upper and lower brackets 152, 154 further comprise generally
vertical gussets 166, 168, respectively, which are secured to the
upright 116 and extend generally perpendicularly from the
transverse edges 169 of the horizontal plates 156, 158. The gussets
166 of the upper bracket 152 are directed downwardly, and the
gussets 168 of the lower bracket 154 are directly upwardly. The
gussets 166, 168 serve to brace the horizontal plates 156,158 of
the upper and lower brackets 152, 154, respectively, and can
provide other functions as will be described hereinafter.
[0054] The pivoting portion 150b of the pivot joint 125 comprises a
generally vertical bore 170 extending through the inner end 122 of
the arm 120. The bore 170 can be substantially cylindrical, having
a cylindrical wall 171 with open upper and lower ends 172, 174,
respectively. The bore 170 is aligned with the apertures 162, 164
of the upper and lower pivot brackets 152, 154, respectively, and
the pin 160 extends through the bore 170 so that the arm 120 may
pivot about the pin 160.
[0055] Upper and lower annular bushings 176, 178 can be provided at
the upper and lower ends 172, 174, respectively, of the bore 170 to
enhance the pivoting action of the arm 120 about the pivot axis
151. In the embodiment illustrated, the bushings 176, 178 have an
inner diameter sized to provide a sliding fit with the pin 160, and
an outer diameter sized to fit snugly within the bore 170.
Furthermore, the upper and lower bushings 176, 178 have flanges 179
that engage the upper and lower faces 180, 182, respectively, of
the arm 120 adjacent the bore 170, thereby keeping the bushings
176, 178 from migrating inwards from the opposed ends 172, 174 of
the bore 170. The bushings 176, 178 can be constructed of a
relatively hard, wear-resistant material, such as for example, an
injection molded plastic or nylon.
[0056] Referring still to FIG. 5, the seating apparatus 100 is
further provided with biasing means 184 for biasing the swing arm
120 to the stowed position 126. The biasing means 184 can
advantageously comprise a flat coiled torsion spring 185 having a
first end 186 fixed directly or indirectly to the upright 116, and
a second end 188 fixed directly or indirectly to the arm 120. In
the illustrated embodiment, the torsion spring 185 is fitted in the
pivot joint 125 of the apparatus 100. More particularly, the
torsion spring 185 comprises a thin strip of resilient metal coiled
in flat spiral about the pivot axis 151. The torsion spring 185 is
positioned between the flange 179 of the upper bushing 176 and the
horizontal plate 156 of the upper bracket 152.
[0057] An axially extending boss 190 is provided between the flange
179 of the upper bushing 176 and the horizontal plate 156 of the
upper bracket 152. The boss 190 has an outer diameter that is
smaller than the inner diameter of the smallest coil of the torsion
spring 185, so that the boss 190 can extend axially through the
center of the torsion spring 185.
[0058] The boss 190 is fixed to pivot with the arm 120. In the
embodiment illustrated, the boss 190 extends from the upper bushing
176 of the pivot joint 12. Anti-rotate means 192 are provided
adjacent the bushing 176 and the bore 170 for preventing relative
rotation between the bushing 176 and the bore 170, and hence,
between the boss 190 and the arm 120. The anti-rotate means 192 can
comprise an axial groove 194 provided along the outer surface of
the bushing 176, and a radially inwardly directed key 195 extending
from the inner surface of the bore 170 shaped to fit within the
groove 194.
[0059] Furthermore, in the embodiment illustrated, the first
(radially outermost) end 186 of the torsion spring 185 comprises a
radially outwardly extending hook 196 that is hooked onto an
exposed vertical edge 167 of the adjacent gusset 166. The second
(radially innermost) end 188 of the torsion spring 185-comprises a
radially inwardly directed tab 198. The boss 190 is provided with a
transverse slot 199 for receiving the tab 198. Accordingly, the
first end 186 of torsion spring 185 is fixed to the upright 116,
and the second end 188 of the torsion spring 185 is secured to the
swing arm 120.
[0060] It is to be appreciated that the elements of the pivot joint
125 can be assembled quite easily. In particular, the bushing 176
can be axially inserted into the upper end 172 of the bore 170 of
the arm 120 once the groove 194 has been aligned with the key 195.
The torsion spring 185 can be placed over the boss 190 of the
bushing 176, ensuring that the tab 198 is positioned within the
slot 199. With the lower bushing also inserted in the bore 170, the
inner end 122 of the arm 120 can be positioned between the plates
156, 158 of the upper and lower brackets 152,154, respectively.
[0061] When inserting the arm 120 between the brackets 152, 154,
the hook 196 of the torsion spring 185 can be aligned to engage the
edge 167 of the gusset 166. This will generally require a light
force on the torsion spring 185, since the torsion spring 185 is
preferably pre-loaded. More particularly, the torsion spring 185
can exert a certain pre-load torque on the arm 120 even when the
arm 120 is in the stowed position.
[0062] Referring now to FIGS. 5 and 6a, to define the deployed
position 128 of the arm 120, the seating apparatus 100 can be
provided with static and dynamic advanced stop elements 200 and
202, respectively. The static advance stop element 200 is fixed to
the upright 116. The dynamic advance stop element 202 is secured
to, and moves with, the arm 120. The advance stop elements 200, 202
are positioned relative to each other such that pivoting of the arm
120 from the stowed position 126 to the deployed position 128
causes the dynamic advance stop element 202 to contact the static
advance stop element 200, thereby preventing further pivoting of
the arm 120 beyond the deployed position 128 (FIG. 6b, and shown in
phantom in FIG. 3).
[0063] In the embodiment illustrated, the static advance stop
element 200 comprises the exposed vertical edge 167 of the
rear-most gusset 168b of the lower pivot joint bracket 154. The
dynamic advance stop element 202 comprises a lug 204 welded to the
underside of the arm 120.
[0064] The apparatus 100 can also be provided with static and
dynamic return stop elements 206 and 208, respectively, for
defining the stowed position 126 of the arm 120. The static return
stop element 206 is fixed to the upright 116, and the dynamic
return stop element 208 is secured to the arm 120.
[0065] In the embodiment illustrated, the static return stop
element 206 comprises the exposed vertical edge 167 of the forward
gusset 168a of the lower pivot bracket 154. The exposed vertical
edge 167 presents a static return abutment surface 207 against
which the dynamic return stop 208 can abut.
[0066] The dynamic return stop element 208 comprises a button 210
that is secured to the arm 120. The button 210 is generally
cylindrical in shape having a generally flat mounting face 212
positioned against the arm 120, and an outer diameter surface 214
for contacting the static return stop element 206.
[0067] At least one of the static and dynamic return stop elements
206, 208 may be adjustably secured to the apparatus 100, i.e. to
the upright 116 or the arm 120, respectively, so that the stowed
position 126 of the arm 120 relative to the upright 116 may be
adjusted. In the embodiment illustrated, the button 210 is
eccentrically mounted to the arm 120 along a mounting axis 216.
Accordingly, rotating the button 210 about the mounting axis 216
changes the distance 218 between the mounting axis 216 and the
static return stop 206 when the static return stop 206 is in
contact with the surface 214 of the button 210. This in turn
changes the angular position of the arm 120 relative to the upright
116 when the arm 120 is in the stowed position 126 (FIG. 6c, and
shown in solid line in FIG. 3).
[0068] As a result, the width of the narrow gap 130 between the
backrest 112 of the seat 104 and the adjacent edge 114 of the work
surface 106 when the arm 120 is in the stowed position 126 may be
increased or decreased by changing the rotational position of the
eccentrically mounted button 210.
[0069] This feature can be advantageous for a variety of reasons.
For example, it is generally desirable to have a stowed position
126 for the seats 104 wherein the backrest 112 of the seat 104 is
close to, but not in contact with, the adjacent edge 114 of the
work surface 106 (i.e. spaced by the narrow gap 130). If the
backrest 112 contacts the work surface 106, premature wear or
damage to the seating apparatus 100 could result. If the backrest
112 is spaced too far from the work surface 106 when the arm 120 is
in the stowed position 126, clear passage behind the seat 104 is
compromised. By providing an adjustable return stop element 206 or
208, the position of the seat 104 with respect to the work surface
106 when in the arm 120 is in the stowed position 126 can be
optimized after installation of the seating apparatus 100, despite
any expected variations in fabrication or assembly of the various
apparatus components. Furthermore, by providing an adjustable
return stop element 206, 208, all of the seats 104 in a row can be
adjusted to be spaced equally apart from the work surface 106 by
the narrow gap 130 when the seats 104 are in the stowed position
126, thereby providing a neat, professional appearance (FIG.
3).
[0070] Referring now to FIG. 7, the outer end 124 of the arm 120
can be provided with a swivel mechanism 220 for swivelably mounting
the seat 104 to the arm 120. The swivel mechanism 220 can enable
the seat 104 to rotate to the left or to the right
(counterclockwise or clockwise when viewed from above) from a
central position 222 in which the seat 104 faces the forward
direction 135. In the embodiment illustrated, when in the central
position 222, the seat 104 is oriented such that the backrest 112
of the seat 104 is generally in parallel alignment with the
adjacent edge 114 of the work surface (as seen in FIG. 3).
[0071] The swivel mechanism 220 can comprise a cartridge 224 fitted
in a cylindrical housing 226 provided adjacent the outer end 124 of
the swing arm 120. The swivel mechanism 220 can have orientation
biasing means 228, for biasing the seat 104 to the central position
222.
[0072] In the embodiment illustrated, the cartridge 224 comprises a
seat post 230 to which the seat 104 can be attached by means of a
seat mounting bracket 232. The seat post 230 is rotatably supported
by the cartridge 224, and the cartridge 224 is fixed within the
housing 226.
[0073] Referring now to FIG. 8, the housing 226 is generally
cylindrical, having open upper and lower ends 236, 238,
respectively. The cartridge 224 comprises a cylindrical sleeve 240
which is received in the housing 226. The sleeve 240 can be secured
in the housing 226 by means of radial locking screws 242 provided
around the circumference of the housing 226. In the embodiment
illustrated, three locking screws 242 are provided.
[0074] The sleeve 240 is also generally cylindrical in shape,
having open upper and lower ends 246 and 248, respectively. The
lower end of the sleeve is provided with a radially inwardly
directed retaining lip 249. The retaining lip 249 can be integrally
formed with the sleeve 240, by means of, for example but not
limited to, a swaging process. The inner diameter of the retaining
lip is, in the embodiment illustrated, larger than the outer
diameter of the seat post 230.
[0075] The cartridge 224 further comprises a lower bushing 250
positioned in the sleeve 240 adjacent the retaining lip 249. The
bushing 250 has an outer diameter providing a sliding fit within
the sleeve 240, and an inner diameter to provide a sliding fit with
the outer surface of the post 230. A lower spring seat surface 251,
characterized by generally flat, annular surface, is provided
adjacent the upper axial face of the bushing 250. [0076] The
orientation biasing means 228 of the swivel mechanism 220 comprises
upper and lower orientation cams 252, 254, respectively, and a
compression spring 255 provided about the seat post 230 within the
cartridge 224.
[0076] In the embodiment illustrated, with reference to FIGS. 8a
and 8b, the upper and lower cams 252, 254 are in the form of
annular collars having generally cylindrical outer side surfaces
256 and 258, respectively. The upper cam 252 has an inner diameter
providing a sliding fit with the outer surface of the seat post
230. The upper end of the upper cam 252 comprises a radially
outwardly extending flange 260. The lower end of the upper cam 252
is provided with an upper cam surface 262, which comprises a
generally planar surface oriented at an incline to the axis of the
seat post 230. The inclined upper cam surface 262 presents
vertically uppermost and lowermost points 264 and 266,
respectively.
[0077] The lower cam 254 has an inner diameter providing a snug fit
with the outer surface of the seat post 230. The lower end of the
lower cam 254 has a generally flat spring seat surface 270 oriented
perpendicularly to the axis of the post 230. The upper end of the
lower cam 254 is provided with a lower cam surface 272, which
comprises a generally flat annular surface oriented at an incline
to the axis of the seat post 230 that matches the incline of the
upper cam surface 262. The inclined lower cam surface 272 presents
vertically uppermost and lowermost points 274 and 276,
respectively.
[0078] In the assembled cartridge 224, the lower cam 254 is fixed
to the seat post 230, by, for example, a set screw 255, so that the
seat post 230 and the lower cam 254 move together. The compression
spring 255 is provided in the sleeve 240 between the lower bushing
250 and the spring seat surface 270 of the lower cam 254. The upper
cam 252 is inserted in the sleeve 240 so that the flange 260 abuts
the upper face of the sleeve 240, and the upper cam is fixed to the
sleeve in that position. In the embodiment illustrated, radial
locking rivets 241 extend through the sleeve 240 and engage the
sides 256 of the upper cam 252 to lock the upper cam 252 in
position relative to the sleeve 240.
[0079] In use, the inclined cam surfaces 262 and 272 of the upper
and lower cams 252, 254 are in substantially flush contact around
the circumference of the cam surfaces 262, 272 when the seat 104 is
in the central position 222 (FIGS. 8 and 9). When the seat 104 and
seat post 230 are rotated (swiveled) in either direction, the lower
cam 254 rotates with the post 230, and the post 230 and seat 104
are forced downward as the uppermost point 274 of the lower cam 254
follows the downwardly inclining cam surface 262 of the upper cam
252. This downward translation of the seat 104 compresses the
spring 255 and causes the lower end 282 of the seat post 230 to
protrude beyond the lower end of the lower bushing 250 (FIG.
10).
[0080] It is to be appreciated that the swivel mechanism 220
provides a relatively simple and inexpensive mechanism for
swiveling the seat 104 and biasing the seat 104 to a central
position 222.
[0081] Furthermore, the amount of rotation for swiveling the seat
104 can be limited by the vertical clearance 288 provided between
the upper end of the cartridge 224 and the lower surface of the
seat mounting bracket 232 fixed to the post 230. In the embodiment
illustrated, about 90 degrees of rotation of the seat 104 uses up
the available vertical clearance 288, causing the seat mounting
bracket 232 to bottom out against the uppermost end of the
cartridge 224, thereby defining the maximum swivel position 223
(FIG. 10). A metal washer 290 can be provided above the upper face
of the flange 260 of the upper cam 252, to protect the flange 260
from damage that could result if the seat 104 is aggressively
swiveled to its maximum rotation position.
[0082] When the seat 104 is released, the upward force of the
compression spring 255 is transferred by the inclined cam surfaces
262, 272 of the cams 252, 254 into a rotational force, so that the
seat 104 will swivel back to the central position 222. When in the
central position 222, the lower cam 254 is at its vertically
uppermost position, the adjacent cam surfaces 262, 272 of the cams
252, 254 are in substantially flush contact, and the spring 255 is
in its least compressed state.
[0083] In combination with the pivoting action provided by the
swing arm 120, it will be understood that an occupant of the seat
104, after entering the seat 104, can adjust the position of the
seat 104 relative to the work surface 106 by swiveling the seat 104
and by pivoting the swing arm 120 to any desired position between
the deployed 128 and stowed positions 126 of the arm 120. To exit
the seat 104, an occupant can push back against the floor 108
and/or the work surface 106 using his or her feet and hands,
respectively, so that the arm 120 is moved to the deployed position
128 and the access space 132 is provided between the backrest 112
of the seat 104 and the adjacent edge 114 of the work surface 106
(FIG. 2).
[0084] Upon releasing the unoccupied seat 104, the seat 104 will
swivel to the central position 222 and the arm 120 will pivot to
the stowed position 126. In this position, the backrest 112 of the
seat 104 is preferably near, but not in contact with, the adjacent
edge 114 of the work surface 106. The precise position of the
backrest 112 of the seat 104 relative to the adjacent edge 114 of
the work surface 106 can be adjusted using the adjustable dynamic
return stop element 210 of the illustrated embodiment, as
previously described.
[0085] According to another feature of the present invention, and
with reference now to FIG. 11, the uprights 116 of the seating
apparatus 100 can be inclined from the vertical, such that the
upright 116 has opposed upper and lower ends 302 and 304,
respectively, with the upper end 302 positioned forward (relative
to the direction 135) of the lower end 304 of the upright 116.
[0087] The inclined upper portion 306 of the upright 116 (between
the work surface 106 and the pivot joint 125) advantageously
positions the pivot axis 151 of the pivot joint 125 further
rearward relative to the adjacent edge 114 of the work surface 106
than would be possible with a generally vertical upright. The
inclined lower portion 308 of the upright 116 (between the floor
108 and the pivot joint 125), being in colinear relation with the
upper portion 306, enables a straight continuous length of material
to be used as the upright 116.
[0086] In the embodiment illustrated, the upright 116 comprises a
straight length of steel pipe having an axis 307. The upper and
lower ends 302 and 304 of the upright 116 are cut at right angles
to the axis 307 of the upright 116, producing generally
perpendicular upper and lower end faces 302a and 304a,
respectively. By using a straight but inclined upright 116, the
need of a more costly two-piece, or bent, upright is avoided.
Furthermore, by having square ends 302 and 304, more costly oblique
cuts are avoided.
[0087] The inclined lower portion 308 of the upright 116 (i.e. the
length of the upright 116 between the floor 108 and the pivot joint
125) can advantageously provide an attachment locus 309 for
attaching the upright 116 to the floor 108 that is positioned
rearward of the pivot axis 151. The attachment locus 309 is
generally defined by the intersection of the axis 307 of the
upright 116 and the plane defined by the end 304 of the upright
116. The rearward offset of the attachment locus 309 can position
the attachment of the upright 116 to the floor 108 closer to the
center of the seat 110 (i.e. closer to the post 230, which can
improve the load distribution of an occupant over the floor
attachment and reduce stress loads on the floor attachment
accordingly. In the embodiment illustrated, the floor attachment is
provided by using a floor bracket 314, described in greater detail
subsequently herein. Further, in the embodiment illustrated, the
attachment locus 309 of the upright 116 is positioned sufficiently
rearward to be at least partially further rearward than a forward
edge 111 of the seat base 110 when in the deployed position
128.
[0088] Since the pivot axis 151 is generally vertical, as desired
for the swing arm 120 to pivot in a horizontal plane, the pivot
axis 151 is correspondingly inclined to the axis 307 of the upright
116. In the illustrated embodiment, the upper and lower brackets
152, 154 of the pivot joint 125 are offset to opposite sides of the
centerline of the upright 116, and oriented to vertically opposed
each other (FIG. 11). The brackets 152, 154 are then welded in
place to the upright 116.
[0089] To provide attachment to the work surface 106 and the floor
108, the upper and lower ends 302, 304 of the upright 116 are
fitted with a work surface bracket 312 and a floor bracket 314,
respectively. The work surface bracket 312 can have a generally
horizontal mounting surface 316 to which the work surface 106 can
be secured. The work surface bracket 312 can further be provided
with an inclined attachment surface 318 to which the upper end 302
of the upright 116 can be fastened. The inclined attachment surface
318 can be inclined relative to the mounting surface 316 to abut
the upper end face 302a of the upright 116 in generally flush
contact.
[0090] The floor bracket 314 can have a flange portion 319
presenting a generally horizontal bearing surface 320 to bear in
flush engagement against the floor 108. The floor bracket 314 can
provide an attachment pocket 321 for receiving the lower end 304 of
the upright 116 and facilitating attachment of the floor bracket
314 to the upright 116.
[0091] The attachment pocket 321 can include an inclined base 322
that is adapted to provide flush engagement with the lower end face
304a of the upright 116. Accordingly, the inclined base is inclined
with respect to the horizontal, but is generally parallel to a
plane defined by the lower end face 304a. The flush engagement of
the lower end face 304a of the upright 116 and the base 322 of the
attachment pocket 321 can facilitate providing accurate alignment
of the floor bracket 314 relative to the upright 116, and providing
a secure and reliable joint between the floor bracket 314 and the
upright 116.
[0092] The floor bracket 314 can advantageously be manufactured of
a relatively heavy gauge metal sheet, and can be formed in a press
or stamping operation. The floor bracket 314 and upright 116 can be
joined by inserting the upright 116 into the attachment pocket 321,
so that the lower end face 304a bears in flush engagement against
the base 322. The floor bracket 314 and the upright 116 can then be
welded together.
[0093] Referring now to FIGS. 12, 12a, and 12b, an alternate
embodiment of a floor bracket 314' can be provided to facilitate
installing the apparatus 100 on an inclined floor surface 108',
such as commonly found in auditoriums with downward sloping floors.
The floor bracket 314' has an attachment pocket 321' with an
inclined base 322'. The inclined base 322' is generally inclined
relative to the horizontal, and is adapted to provide flush
engagement with the lower end face 304a of the upright 116.
Depending on the steepness of the sloped floor 108', the inclined
base 322' may be inclined relative to the bearing surface 320' of
the floor bracket 314' (FIG. 12a), or may be generally parallel to
the bearing surface 320' (FIG. 12b).
[0094] Referring now to FIG. 13, an alternate embodiment of a
swivel mechanism 220' is shown. The swivel mechanism 220' is
similar to the swivel mechanism 220 (FIG. 8), and like elements are
generally denoted by like reference numerals, those with a prime
suffix having modifications described in greater detail herein.
[0095] The swivel mechanism 220' includes, in the embodiment
illustrated, a modified cartridge 224' adapted to fit into a
modified cylindrical housing 226' secured to the outer end 124 of
the swing arm 120.
[0096] The cartridge 224' includes a modified orientation biasing
means 228' housed in the cylindrical sleeve 240. The orientation
biasing means 228' of the swivel mechanism 220' includes modified
upper and lower orientation cams 252' and 254', respectively.
[0097] Referring now also to FIGS. 13a and 13b, the upper and lower
orientation cams 252', 254' are in the form of annular collars
having generally cylindrical outer side surfaces 256' and 258'. The
lower end of the upper cam 252' is provided with an upper cam
surface 262', which in the embodiment illustrated, follows an
undulating path having two vertically uppermost points defining
troughs 264a' and 264b', and two vertically lowermost points
defining crests 266a' and 266b' of the upper cam 252'.
[0098] The two troughs 264a' and 264b' are generally disposed
180.degree. apart with respect to the axis of the upper cam 252'.
Similarly, the two crests 266a' and 266b' are generally disposed
180.degree. apart from each other, and 90.degree. apart from the
troughs 264a', 264b'.
[0099] The lower cam 254' has an upper end that is provided with a
lower cam surface 272' that is adapted to engage or follow (as in a
cam follower) the upper cam surface 262'. The lower cam surface
272', in the embodiment illustrated, follows an undulating path
around the perimeter of the lower cam 254', and has two vertically
uppermost points or crests 274a', 274b', and two vertically
lowermost points or troughs 276a', 276b'.
[0100] In the assembled cartridge 224' (FIG. 13), the lower cam
254' can be secured to the seat post 230 by means of, for example,
a set screw 255. The upper cam 252' can be fixed within the upper
end 246 of the sleeve 240 by means of, for example, radial locking
rivets 241.
[0101] The cartridge 224' can be secured to the swing arm 120 by
inserting the sleeve 240 into the housing 226'. Radial locking
screws 242 can be used to secure the sleeve 240 in the housing
226'. However, it has been discovered that over extended use, the
screws 242 can work loose. Referring now also to FIG. 14, to
facilitate providing a durable assembly of the cartridge 224' into
the housing 226' that does not loosen over time, the housing 226'
can advantageously be provided with upper and lower sleeve
engagement elements 401, 403 extending radially inwardly of the
housing 226', and adjacent respective upper and lower ends 236, 238
thereof.
[0102] In the embodiment illustrated, the sleeve engagement
elements 401, 403 are in the form of annular constrictions that are
pressed or swaged into the sidewall of the housing 226'. The sleeve
engagement elements 401, 403 are adapted to provide a narrowed
inner diameter that closely matches the outer diameter of the
sleeve 240 to provide a snug, near press-fit assembly of the sleeve
240 within the housing 226'. To provide such a closely toleranced
fit over the entire axial length of the housing 226' would be cost
prohibitive, if possible at all. The localized engagement of the
sleeve engagement elements 401, 403 with the sleeve 240, combined
with radial locking screws 242 has been found to provide secure,
durable assembly of the cartridge 224' within the housing 226'.
[0103] In use, as best seen in FIG. 15, the undulating cam surfaces
262' and 272' of the upper and lower orientation cams 252', 254,
respectively, are in substantially flush contact around the
entirety of the circumference of the cam surfaces 262', 272' when
the seat is unoccupied and oriented so that the crests 274a' and
274b' of the lower cam 254' are seated within the troughs 264a' and
264b' of the upper cam 254' (i.e. the central position 222'). When
a weight, such as of an occupant, is placed on the seat 104, the
lower cam 254' (secured to the seat post 230) is urged downward,
against the force of spring 255. The downward displacement of the
seat 104, post 230, and lower cam 254' will generally be limited by
the engagement of the seat mounting bracket 232 against the washer
290. This displacement amount is defined by the vertical space 288'
(FIGS. 15 and 16).
[0104] The vertical distance (or axial extent) between the
uppermost and lowermost points (i.e. the trough 264a', 264b' and
crest 266a', 266b') of the upper cam member 252' defines a
crest-to-trough axial extent 288a'. The crest-to-trough axial
extent 288a' can advantageously be sized to be less than the
vertical spacing 288'. Such a smaller axial extent 288a' provides
an axial gap 288b' between the crests 266a', 266b' of the upper cam
252' and opposing crests 274a', 274b' of the lower cam 254' (FIG.
16). The size of the axial gap 288b' is generally defined by the
difference between the spacing 288' and the crest-to-trough axial
extent 288a'. The gap.288b' can allow the seat 104 to be swiveled
much more than 90.degree., and in fact a full 360.degree. in the
embodiment illustrated, which can in turn eliminate the possibility
of damage to the cam surfaces 262', 272' when the seat 104 is
swiveled by an occupant.
[0105] This can be further understood by considering that when the
seat is unoccupied, the spring urges the post 230 and the attached
lower cam 254' to their raised position. In the raised position,
the cam surfaces 262' and 272' are in generally flush contact, and
the crest 266a' is seated within the trough 276a' to define a
central orientation position 222' of the mechanism 220' (FIG. 15).
When the seat is occupied, and remains oriented in the central
oriented position 222' (i.e. the crests 266a' and 266b' of the
upper cam 252' in rotational alignment with the troughs 276a' and
276b', respectively of the lower cam 254'), the axial spacing
between the opposed cam surfaces 262' and 272' is generally equal
to the spacing 288' (i.e. consider a direct downward displacement
of the lower cam 254' by an amount equal to the gap 288' in FIG.
15). As the seat and lower cam 254' are rotated relative to the
upper cam 252', the respective cam surfaces are no longer parallel,
and the axial spacing between them decreases (FIG. 16). The spacing
becomes narrowest at about a 90.degree. rotation (FIG. 16), but the
cam surfaces remain spaced apart (by the gap 288b') when the seat
is occupied (i.e. when the post 230 and lower cam 254' are moved to
the lowered position).
[0106] This can be contrasted to the mechanism 220 (FIGS. 8, 9, and
10), where, at a rotation of slightly more than 900 away from the
forward position, the seat bracket 232 will abut the washer 290,
and the lower cam 272 surface will strike the upper cam surface
262, and since no further axially downward movement of the lower
cam 254 is possible, further rotation is also not possible. This
interference of the cam surfaces, when the lower cam 254 is at its
maximum axially downward position defines the maximum rotational
limit of the seat. Abrupt or forceful rotation to this maximum
rotational limit can cause the cam surfaces 262, 272 to damage each
other at their contact point of interference.
[0107] Referring again to FIG. 16, providing the gap 288b'
eliminates potential interference of the cam surfaces 262', 272'
during rotation of the seat, thus eliminating this potential cause
of damage. Furthermore, although not necessary to provide the gap
288b', the dual-lobed cam design provides a second stable position
disposed 180.degree. from the forward oriented position, in which
the crest 274a', 274b' is seated in the trough 264a', 264b'. If the
seat 104 is rotated less than 90.degree. in either direction from
the forward orientation, the seat 104 will be urged to the forward
orientation when released. If the seat is rotated more than
90.degree. from the forward orientation, the seat 104 will
generally be urged to the second stable position. The second stable
position can be useful for providing, for example, temporary
clearance under the work surface for cleaning purposes or the
like.
[0108] While preferred embodiments of the invention have been
described herein in detail, it is to be understood that this
description is by way of example only, and is not intended to be
limiting. The full scope of the invention is to be determined from
reference to the appended claims.
* * * * *