U.S. patent number 3,814,474 [Application Number 05/260,448] was granted by the patent office on 1974-06-04 for detachable tablet arm and bookrack.
This patent grant is currently assigned to Steelcase Inc.. Invention is credited to Michael J. Armstrong, Richard H. Baker, Donald E. McNally.
United States Patent |
3,814,474 |
Baker , et al. |
June 4, 1974 |
DETACHABLE TABLET ARM AND BOOKRACK
Abstract
This chair includes a detachable tablet arm and bookrack. The
tablet arm includes a pair of supporting legs which pass beneath
the air seat. Each leg includes a projecting tab which hooks into a
receiving well created by a deformation in a seat supporting flange
at the side of the chair. The ends of the legs are bolted to
similarly formed receiving wells at opposite sides of the chair.
The bookrack includes a platform which hooks over a crossbar
joining the front legs of the chair. A supporting back projecting
upwardly from the rear of the platform includes a pair of
oppositely directed tabs for insertion into the rear receiving
wells on the seat supporting flanges.
Inventors: |
Baker; Richard H. (Grand
Rapids, MI), McNally; Donald E. (Grand Rapids, MI),
Armstrong; Michael J. (Grand Rapids, MI) |
Assignee: |
Steelcase Inc. (Grand Rapids,
MI)
|
Family
ID: |
22989207 |
Appl.
No.: |
05/260,448 |
Filed: |
June 7, 1972 |
Current U.S.
Class: |
297/160;
297/188.12; 297/411.26 |
Current CPC
Class: |
A47C
7/62 (20130101); A47C 7/68 (20130101); A47C
7/705 (20180801) |
Current International
Class: |
A47C
7/62 (20060101); A47C 7/68 (20060101); A47b
035/00 () |
Field of
Search: |
;297/192,416,189,188,160,161,162,440,442 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: McCall; James T.
Attorney, Agent or Firm: Price, Heneveld, Huizenga &
Cooper
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. In a chair with detachable bookrack and tablet arm, said tablet
arm including an arm platform and at least one supporting leg
depending therefrom and passing beneath the seat of said chair, the
improvement comprising: said leg having a leg tab secured thereto
and projecting therefrom; said bookrack including a platform, a
support projecting upwardly therefrom and a support tab projecting
from said support; said chair including receiving means connected
thereto and positioned beneath said seat, said receiving means
defining a recess for matingly receiving both said leg tab and said
support tab.
2. The chair of claim 1 comprising: said leg tab being positioned
generally at a first side of said seat; said leg including securing
means positioned beneath said seat generally at the second side
thereof; said bookrack support including spaced first and second
legs joined at the upper ends by a crosspiece; said crosspiece
being broken intermediate said legs and including means for joining
the two portions thereof; each crosspiece portion including one of
said support tabs, said support tabs projecting in opposite
directions away from the center of said crosspiece; said chair
including one of said receiving means for each of said support
tabs, each of said receiving means being positioned generally at
opposite sides of said chair with said recesses opening towards one
another; each of said receiving means being adapted to receive both
a support tab and said leg tab and each of said receiving means
including engaging means for matingly engaging said securing means
on said leg whereby said tablet arm can be either a left-handed or
a right-handed tablet arm; said bookrack being sufficiently
resiliently flexible that said crosspiece portions can be separated
and compressed inwardly towards one another to facilitate insertion
of said support tabs into said receiving means.
3. The chair of claim 2 in which: said first and second legs of
said bookrack are resiliently flexible.
4. The chair of claim 2 comprising: said first side of said seat
being that side of said seat adjacent said arm platform.
5. The chair of claim 4 in which said receiving means comprises: a
well depending downwardly from said seat, leaving a space between
the bottom of said seat and said well.
6. The chair of claim 5 in which said tablet arm includes a second
leg depending downwardly therefrom and passing beneath the seat of
said chair; said second leg being positioned forwardly of the first
leg; said second leg including a tab being secured thereto and
projecting therefrom and said second leg including a securing means
at its end; said chair including a pair of front downwardly
depending wells, each generally at the front and one at each side
of said chair for matingly receiving said tab and each including an
engaging means for engaging said securing means.
7. The chair of claim 5 in which: each said support tab for said
bookrack comprises: a side wall, a base and a tab, said side wall
being secured to and projecting upwardly from said crosspiece
portion, said base projecting generally laterally from said side
wall and said tab projecting from said base; each said leg tab
comprising a side wall, a base and a tab, said side wall being
secured to said leg and projecting upwardly therefrom, said base
projecting generally laterally from said side wall; each said side
wall of each said leg tab and said support tab including a portion
projecting therefrom in the same direction as its respective tab,
but at a lower level, spaced therefrom; each said receiving means
including a notch for receiving said side wall of said leg tab
member and having a notch for receiving said side wall of said
support tab member; said side walls resting in said respective
notches, said tabs being positioned within said receiving means on
the upper surface thereof and said projecting side wall portions
being positioned below said receiving means.
8. The chair of claim 7 in which said chair seat is mounted on a
pair of flanges, each of said flanges being secured to said chair
generally at the side thereof; each of said wells being defined by
a downward deformation in said flange.
9. The chair of claim 8 in which said platform and said chair
include means cooperating to secure said platform to said chair,
said cooperating means being disposed generally at the front of
said chair and at the front of said platform.
10. The chair of claim 9 in which said means cooperating comprise:
at least one hook on the front of said platform and a crossbrace
extending between and joining the front legs of said chair.
11. The chair of claim 1 in which: said support tab for said
bookrack comprises: a side wall, a base and a tab, said side wall
being secured to and projecting upwardly from said support, said
base projecting generally laterally from said side wall and said
tab projecting from said base; said leg tab comprising a side wall,
a base and a tab, said side wall being secured to said leg and
projecting upwardly therefrom, said base projecting generally
laterally from said side wall and said tab projecting from said
base; each said side wall of each said leg tab and said support tab
including a portion projecting therefrom in the same direction as
its respective tab, but at a lower level, spaced therefrom; said
receiving means including a notch for receiving said side wall of
said leg tab member and having a notch for receiving said side wall
of said support tab member; said side walls resting in said
respective notches, said tabs being positioned within said
receiving means on the upper surface thereof and said projecting
side wall portions being positioned below said receiving means.
12. In a chair with detachable tablet arm, said tablet arm having
an arm platform and at least one supporting leg depending
downwardly therefrom and passing beneath the seat of said chair,
the improvement comprising: said leg having a leg tab secured
thereto and projecting therefrom; said chair including receiving
means defining a recess beneath said seat for matingly receiving
said leg tab to thereby support and locate said leg beneath said
seat; said leg tab being positioned generally at a first side of
said seat; said leg including securing means positioned beneath
said seat and generally at the second side of said seat; said chair
including engaging means positioned beneath said seat for matingly
engaging said securing means.
13. The chair of claim 12 comprising: said first side of said chair
being that side of said chair which is adjacent said arm
platform.
14. The chair of claim 13 comprising: said leg tab projecting from
said leg generally towards the side of said chair at which said
tablet arm is located.
15. The chair of claim 14 in which said receiving means comprises:
a well depending downwardly from said seat generally at said first
side thereof.
16. The chair of claim 15 in which said leg tab comprises a side
wall, a base and a tab, said side wall being secured to and
projecting upwardly from said leg and said base projecting
generally laterally from said side wall; said tab projecting
outwardly from said base; said side wall including a portion
projecting beyond the end of said base in the same direction as
said tab, but being spaced from said tab at a level below that of
said tab; said well including a notch therein for matingly
embracing said side wall with said tab lying within said well on
the upper surface thereof and said projecting side wall portion
lying beneath said well on the underside thereof.
17. The chair of claim 16 in which said leg tab includes a second
wall secured to said leg and projecting upwardly therefrom and then
being joined to said base, said leg tab being generally U-shaped in
configuration; said well including a second notch therein defining
a tongue between said notches; said second side wall being matingly
engaged by said second notch and said tab overlying said
tongue.
18. The chair of claim 16 in which said engaging means comprises: a
second well depending downwardly from said seat, generally at said
second side thereof; said well having an aperture therein; said
securing means comprising a bolt passing through the end of said
leg and through said aperture; the space between said receiving
well and seat being sufficiently large that a nut can be inserted
therein; a nut being inserted in said well with said bolt being
threaded in said nut.
19. The chair of claim 18 in which: said nut includes a hook on one
side thereof for hooking over the edge of said receiving well to
facilitate locating said nut with respect to said aperture and to
prevent said nut from rotating when said bolt is threaded
thereinto.
20. The chair of claim 18 in which: said second well and the first
well are identical in structure whereby said tablet arm can either
be a left-handed or a right-handed tablet arm.
21. The chair of claim 18 in which said chair seat is mounted on a
pair of flanges, each of said flanges being secured to said chair
generally at the side thereof; each of said wells being defined by
a downward deformation in said flange.
22. The chair of claim 15 in which said tablet arm includes a
second leg depending downwardly therefrom and passing beneath the
seat of said chair; said second leg being positioned forwardly of
the first leg; said second leg including a tab being secured
thereto and projecting therefrom sand said second leg including a
securing means at its end; said chair including a front downwardly
depending well generally at the front and at each side of said
chair for matingly receiving said tab and including an engaging
means for engaging said securing means.
23. The chair of claim 15 in which said chair seat is mounted on a
pair of flanges, each of said flanges being secured to said chair
generally at the side thereof; each of said wells being defined by
a downward deformation in said flange.
24. In a chair having a detachable bookrack and tablet arm, said
tablet arm including a pair of legs depending downwardly therefrom
and passing beneath said seat, said chair including a flange at
either side thereof for supporting the chair seat, the improvement
comprising: each of said legs including a tab projecting upwardly
therefrom and towards said tablet arm; said tabs being positioned
beneath said seat generally at the side adjacent said tablet arm;
each of said flanges including a pair of deformations therein in a
downward direction away from the bottom of said seat, said
deformations defining receiving wells for receiving said tabs at
either side of said seat whereby either a left-hand or right-hand
tablet arm can be mounted to said chair; each of said legs
including securing means at the end thereof for securing to the
receiving wells at the side of said chair away from said tablet
arm; said bookrack including a platform and a pair of legs
projecting upwardly generally from the rear thereof, said legs
being joined by a cross-piece which is broken intermediate said
legs; said crosspiece including means detachably joining the two
portions thereof; cooperating means disposed generally at the front
of said chair and said platform cooperating to secure said platform
to said chair; each portion of said crosspiece including a tab
projecting upwardly from said crosspiece and outwardly away from
each other; one of said receiving wells on each of said flanges
being generally at the rear of said seat and being sufficiently
large to receive one of said crosspiece tabs and one of said leg
tabs.
Description
BACKGROUND OF THE INVENTION
The present invention relates to attachments for chairs. More
specifically, it relates to optional tablet arm and bookrack
attachments which serve to increase the versatility of a chair. The
invention is particularly well-adapted for use with stacking
chairs. An example of such chairs is disclosed in patent
application Ser. No. 111,429, owned by the assignee of this
invention, invented by Randall P. Buhk, et al, and filed Feb. 1,
1971.
Conventionally, tablet arms comprise a wooden arm member supported
by a frame connected to the chair. This frame generally includes a
pair of leg members passing beneath the seat and being bolted to
the frame of the chair, generally at each side of the chair. This
requires four sets of bolts and four bolting operations. To perform
the operation quickly, two people are required. One must hold the
frame in place while the other bolts it down. Some prior art chair
and tablet arm combinations even require the removal of the seat
prior to attaching the tablet arm, in order that the same bolts may
be used to hold both the seat and the tablet arm.
As an alternative to bolts, the arms may pass through tubular
members positioned beneath the seat. One problem with this is that
it is diffuclt to slide the arms through the tubes, if any type of
snug fit is to be achieved. In the alternative, the tubes may be
two-section members which can be loosened for sliding the arms
therethrough and which can then be retightened. The only problem
with such an arrangement is that this also requires a number of
different bolting and unbolting operations.
Conventional bookrack attachments are similarly generally bolted to
the chairs. Some prior art bookracks hang over cross-pieces between
the legs of the chair, and include rod portions wrapped around the
crosspieces. In the latter case, however, the bookracks are
generally not readily attachable or detachable.
SUMMARY OF THE INVENTION
In the present invention, a chair is provided having readily
attachable tablet arm, or bookrack, or both. In the case of each
attachment, mounting is facilitated by the attachment member
including a tab projecting from a supporting portion thereof into a
receiving means disposed beneath the chair seat.
In the case of tablet arm, for example, the arm has at least one
supporting leg passing beneath the seat of the chair. The tab is
secured to and projects from this supporting leg. Preferably, the
tab is generally positioned at one side of the seat and the leg
includes a securing means positioned beneath the seat and generally
at the opposite side thereof. The chair includes engaging means for
matingly engaging the securing means. By positioning the tab in the
receiving means, one can positively locate and hold the tablet arm
while effecting engagement of the securing and engaging means. In
fact, the invention further contemplates that the tab and receiving
means will be located on that side of the chair which is adjacent
the tablet arm such that the tablet arm is held in place and
balanced by the tab engaging the receiving means while one
completes the assembly of the securing means to the engaging means.
Such a structure makes the job of attaching the tablet arm to the
chair a simple, one man operation. Further, the load of a person
resting on the tablet arm is transmitted to the frame by a position
interfit or interlock between the tablet arm and frame. This gives
positive security against the tablet arm collapsing. If bolts or
screws were used at this point, they might loosen and fall out
under load.
In the case of the bookrack, the bookrack includes a platform which
is secured generally to the front of the chair by means on the
platform and chair which cooperate to effect such securance. The
platform includes a support depending upwardly therefrom, generally
near the rear thereof. This support includes a tab projecting
therefrom for insertion into the receiving means positioned
generally beneath the seat. In this manner, positive locating and
holding of the bookrack can be effected without any bolting at all.
Preferably, the support includes spaced legs joined at their upper
ends by a crosspiece. The crosspiece is broken between the legs and
includes joining means for holding the separate crosspiece portions
together. Each of the crosspiece portions includes a tab, with the
two tabs projecting in opposite directions, away from each other.
The chair then includes a receiving means positioned generally at
opposite sides of the chair for receiving each of the tabs. The
bookrack itself is preferably sufficiently resiliently flexible
that the crosspiece portions can be separated and compressed
inwardly towards one another to facilitate insertion of the tabs
into the receiving means.
For attaching the bookrack and tablet arm simultaneously, the same
receiving means at the back of the chair is specially adapted for
holding the tabs of both the tablet arm and bookrack. Preferably,
receiving means are positioned on either side of the chair to
facilitate the mounting of the bookrack and to make it possible to
mount either a left or right-handed tablet arm.
Finally, the objects of the present invention are further
facilitated by the specific construction of the tab member. Each of
the tab members is joined to the tablet arm leg or to the bookrack
support by an upwardly depending side wall joined to a base
projecting generally laterally therefrom. The tab itself projects
outwardly from the base. A portion of one of the side walls
projects beyond the end of the base in the same direction as the
tab, but the side wall portion is spaced from the tab and projects
at a level which is below that of the tab. The receiving means on
the chair which cooperates with this tab member comprises a well
defining a recess for receiving the tab. The well includes a notch
therein into which the side wall of the tab can be inserted with
its projecting portion passing beneath the well and with its tab
overlying the top of the well. This unique structure results in a
more positive interlock between the tab and the receiving
means.
These and other objects and advantages of the present invention
will further be understood and appreciated by reference to the
written specification and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a chair embodying the present
invention;
FIG. 2 is a perspective view of the chair with the bookrack and
tablet arm of this invention attached thereto;
FIG. 3 is a bottom plan view of the chair seat, with the central
portions thereof being broken away to facilitate the showing
thereof;
FIG. 4 is a front elevational view of the tablet arm supporting
frame;
FIG. 5 is a bottom plan view of one side of the chair seat showing
the tabs on the tablet arm supporting frame and on the bookrack as
they are about to pass into mating engagement with the receiving
means on the bottom of the chair seat;
FIG. 6 is the same view as FIG. 5 with the aforesaid tabs being
positioned in such mating engagement;
FIG. 7 is a top plan view of a portion of the chair frame, with the
seat removed, showing the tab of a supporting leg for the tablet
arm in mating engagement with a receiving means on the chair
frame;
FIG. 8 is a cross-sectional view taken along plane VIII--VIII of
FIG. 3, with a supporting leg of the tablet arm being secured to
the chair frame;
FIG. 9 is a front elevational view of the bookrack;
FIG. 10 is a side elevational view of the bookrack; and
FIG. 11 is a top plan view of one side portion of the bookrack.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the preferred embodiment, the chair 10 (FIG, 1) includes a front
receiving well 20 and a rear receiving well 30 at each side of the
seat thereof for mating engagement with leg tab members 50 on the
front and rear supporting legs 42 and 43, respectively, of tablet
arm 40, (FIGS. 2 through 7). Rear wells 30 are also adapted for
cooperation with the crosspiece tab members 70 on the rear of
bookrack 60 (FIG. 2, 5, 6 & 9). With tablet arm 40 and bookrack
60 assembled to chair 10, chair 10 takes on the appearance shown in
FIG. 2.
Chair 10 is of the wire rod, stacking variety. It is bascially
similar in construction to the stacking chair described and claimed
in patent application, Ser. No. 111,429 filed Feb. 1, 1971,
entitled CHAIR, and owned by the assignee of the present invention.
It includes a wire rod frame 13 for supporting a seat 14 and back
15 (FIG. 1). Connected to the sides of wire rod frames 13 for
facilitating the support of seat 14 are a pair of side flanges 11
(FIG. 3). Side flanges 11 are preferably stamped from metal and
welded to wire rod frame 13. Each includes several apertures for
receiving bolts 12 which secure seat 14 thereto.
Front receiving well 20 is formed by a deformation downwardly in
each side flange 11 (FIGS. 3 and 8). This leaves a space between
the bottom of seat 14 and the top of each receiving well 20.
Each front receiving well 20 includes a pair of spaced notches 21
which define a tongue 22 (FIG. 3). Notches 21 and tongue 22
cooperate with leg tab member 50 in the manner which is shown in
FIGS. 5 & 6 and which will be more fully described hereinafter.
Receiving well 20 also includes an aperture 23 therethrough which
acts as an engaging means for the end of front tablet arm
supporting leg 42 in the manner which is shown in FIG. 8 and which
will be more fully described hereinafter.
Each of the rear receiving wells 30 is similarly formed by a
downward deformation at the rear of each side flange 11 (FIG. 3).
Each rear receiving well 30 includes a front notche 31, a middle
notch 32 and a rear notch 33. Front notch 31 and middle notch 32
are space to define a front tongue 34 which corresponds generally
to tongue 22. Middle notch 32 and rear notch 33 define a rear
tongue 36. Front and middle notches 31 and 32 and front tongue 34
cooperate with the leg tab 50 on the rear leg 43 of tablet arm 40
in the same manner as tongue 22 and notches 21 cooperate with leg
tab member 50 on front supporting leg 42 (FIGS. 5 & 6). Rear
tongue 35 and rear notch 33 cooperate with crosspiece tabs 70 on
bookrack 60 in the manner which is shown in FIGS. 5 & 6 and
which will be more fully described hereinafter. Rear well 30 also
includes an aperture 36 for engaging the end of rear leg 43, just
as the end of leg 42 cooperates with aperture 23.
Tablet arm 40 comprises an arm platform 41 supported generally by
the upper support portion 48 of a front leg 42 and rear leg 43
(FIGS. 2 and 4). The specific connection between the upper support
portion 48 and arm platform 41 is generally conventional in nature
and facilitates the pivotal movement of arm platform 41 upwardly to
simplify the task of sitting down in or arising from chair 10.
Front legs 42 and rear leg 43 extend downwardly from arm platform
41 and then project inwardly to pass beneath seat 14 of chair
10.
Both front leg 42 and rear leg 43 of tablet arm 40 include a leg
tab member 50 secured thereto (FIG. 4). Each leg tab member 50 is
secured to legs 42 and 43 at a point beneath chair seat 14 near the
point where legs 42 and 43 project inwardly and pass beneath seat
14. When tablet arm assembly 40 is secured to chair 10, leg tab 50
is positioned generally adjacent that side of seat 14 which is
adjacent arm platform 41.
Each leg tab member 50 includes a side wall 51 and a spaced side
wall 53 joined to a base 52 (FIG. 5). Leg tab member 50 is
preferably formed of metal and side walls 51 and 53 are preferably
secured to leg 42 or leg 43 respectively by welding. Tab 54
projects outwardly from base 52.
Projecting from base 52 is tab 54. Side walls 51 and 53 project
upwardly from leg 42 such that tab 54 is spaced above either leg 42
or leg 43 (FIG. 4). Tab 54 projects from base 52 generally towards
tablet arm platform 41, rather than towards the opposite end of leg
42 or 43. The fact that tab 54 points in this direction helps
insure that it will not become accidentally disengaged from
receiving walls 20 or 30 when seat 14 is sat upon. If tab 54 were
pointed inwardly with its receiving well 20 or 30 opening
outwardly, the compressive force tending to compress the sides of
the chair 10 inwardly when seat 14 is sat upon, even though slight,
might tend to cause tab 54 to disengage from its respective
receiving well 20 or 30. By orienting tabs 54 and receiving wells
20 and 30 according to the present invention, any compressive force
tending to move the sides of the chair 10 inwardly will merely tend
to further force tab 54 into either receiving well 20 or 30.
Side wall 51 of tab member 50 includes a portion 55 projecting
beyond the end of base 52 generally in the direction of tab 54
(FIG. 5). Projecting portion 55 projects at a level spaced below
the level of tab 54 (FIG. 4). Thus when tab 54 is inserted into
front receiving well 20, projecting portion 55 is positioned below
the surface of receiving well 20 while tab 54 is positioned above
the surface of receiving well 20 (FIG. 6). Side wall 51 proper is
then received in notch 21 and side wall 53 is received in the
opposite notch 21. Thus tab 54 specifically overlies tongue 22 of
receiving well 20. In this manner, tab member 50 is positively held
in place and is restrained from lateral movement, vertical up and
down movement and longitudinal movement in a direction towards the
outside of chair 10.
Tab 50 on rear leg 43 cooperates with rear receiving well 30 in the
same manner. Thus, side wall 51 is received within middle notch 32,
side wall 53 is received within front notch 31, projecting portion
55 is positioned beneath the surface of receiving well 30 and tab
54 is positioned above front tongue 34.
The end of front leg 42 and of rear leg 43 includes an aperture 44
therethrough for receiving a bolt 45 (FIGS. 4 and 8). Bolt 45 in
front leg 42 extends upwardly and passes through aperture 23 in
receiving well 20 and is threaded into a special nut 46 which is
disposed within front receiving well 20. The space between seat 14
and front receiving well 20 makes it possible to place nut 46 in
this position. Nut 46 is specially adapted for this purpose, having
a hook portion 47 which hooks over the edge of receiving well 20.
By pushing nut 46 inwardly until hook 47 is stopped by the edge of
receiving well 20, one pretty well located the threaded aperture of
nut 46 over aperture 23. Further, hook 47 prevents nut 46 from
turning when bolt 45 is threaded thereinto.
Rear leg 43 includes an identical aperture 44 at its end for
cooperating in an identical manner with a bolt 45 and nut 46 having
a hook portion 47. For rear leg 43, bolt 45 passes through aperture
36 in rear receiving well 30.
Bookrack 60 is formed of a plurality of wire rods welded together
(FIG. 2). It includes a book supporting platform 61 joined to a
back 62. Back 62 serves not only to prevent books from being slid
off the back of platform 61, but also as a support for platform
61.
Thus, back 62 includes a pair of spaced legs 63 projecting upwardly
from either side of platform 61, generally at the rear thereof
(FIGS. 9 through 11). Legs 63 are joined by a crosspiece 65 which
is broken in the middle into two separate crosspiece portions. A
cylindrical, tubular joining tube 66 is welded to one of the
crosspiece portions 65 and is open at its other end such that the
other crosspiece portion 65 can be inserted thereinto.
A crosspiece tab member 70, preferably formed of metal, is welded
to each crosspiece portion 65 near its juncture with its respective
leg 63. Each tab member 70 includes a side wall 71 secured to and
projecting upwardly from crosspiece portion 65 and being joined to
and integral with a laterally projecting base 72 (FIGS. 9 and 5). A
tab 73 projects from base 72 with each of the two tab members 70
being oriented such that the tabs 73 project in opposite directions
away from each other and away from the center of crosspiece 65.
Side wall 71 includes a portion 74 projecting therefrom in the same
direction as tab 73 projects, but at a level spaced below tab 73.
Thus when tab 73 is inserted into rear receiving well 30, it
overlies rear tongue 35 (FIGS. 5 and 6). Wall 71 is received within
rear notch 33 and projecting wall portion 74 is positioned beneath
rear receiving well 30. In this manner, tab member 70 is snugly
received in and mated to rear receiving well 30.
Bookrack 60 is made such that is has sufficient resilient
flexibility that the separate crosspiece portion 65 can be
separated one of said crosspiece members 65 being removed from
joining tube 66, and then compressed inwardly toward one another in
overlapping fashion to facilitate the insertion of tabs 73 into
rear receiving wells 30. The end of one of the crosspiece portions
65 is then reinserted into joining tube 66 such that the tabs 73
are positively held within rear receiving wells 30 by a rigid
crosspiece 65 extending between tab members 70 (FIG. 9). In the
preferred embodiment, the flexibility of bookrack 60 is provided
primarily by the wire rod supporting legs 63.
The front of platform 61 is secured to the front of chair 10 by
means of hooks 67 formed at the ends of the side rods 68 of
platform 61 (FIGS. 2, 9 and 10). These hook over a cross-brace 16
which extends between the two front legs 17 of chair 10. Thus, the
front of platform 61 is supported at the front of chair 10 while
the rear thereof is supported at the rear of chair 10.
OPERATION
In operation, either tablet arm 40 or bookrack 60, or both, can be
readily mounted to chair 10. In order to mount tablet arm 40 to
chair 10, legs 42 and 43 are passed beneath seat 14 and tabs 54 on
leg tab members 50 are hooked into front receiving well 20 and rear
receiving well 30 respectively. Tablet arm 40 is thereby held in
place and can easily be balanced while bolt 45 is passed through
aperture 44 at the end of each leg 42 and 43 and through either
aperture 23 or 36 and is secured to nut 46. The force or load
placed on tablet arm 40 by a person leaning thereon is transmitted
to frame 10 by the positive interlock between tabs 54 and receiving
wells 20. This positive interlock insures that tablet arm 40 will
not inadvertantly collapse under load. Bolts 45 are used only on
the side of frame 10 opposite platform 41 and therefore are not
subjected to a force tending to pull them loose. They need only be
tightened sufficiently to prevent rattling.
Bookrack 60 is secured to chair 10 by hooking hooks 67 over
crossbrace 16. Then, being sure that crosspiece portions 65 are
disengaged, side legs 63 of back 62 are compressed inwardly and
crosspiece tab member 70 are placed in alignment with rear
receiving wells 30. Legs 63 are then allowed to spring back
outwardly such that tabs 73 will automatically pass into and be
received by rear receiving wells 30. Tabs 73 are positively held
within rear receiving wells 30 by again joining crosspiece portions
65 at joining tube 66.
With the attachments thus assembled, one has converted a wire rod
stacking chair 10 into a tablet arm chair suitable for many
instructional uses. This greatly increases the versatility of the
basic chair 10. The fact that the present invention enables tablet
arm 40 and bookrack 60 to be so easily attached to chair 10 is a
significant factor in increasing the versatility of the chair. Of
course, it will be understood that the above is merely a preferred
embodiment of the invention and that many changes and alterations
can be made thereof without departing from the spirit and broader
aspects of the invention.
* * * * *