Note: Descriptions are shown in the official language in which they were submitted.
f . . ~
218357
MULTI-PURPOSE CONVERTIBLE FURNITURE
This invention relates to a new or improved multi-
purpose convertible furniture article and in particular to an
article that can provide, amongst other uses, a bench-type seat,
or a combined table and seat, in the latter configuration the
article also being usable as an elevated platform or staging.
Convertible picnic-type tables have previously been
proposed in various forms, to provide articles that can be used
as tables or benches, sawhorses, scaffolding or other supports,
and examples of such articles can be seen in United States
Design Patent No. D-265,787 and also in U.S. Patent Nos.
1,792,737 Greenstreet, 4,606,575 Kodet and 4,615,559 Blondeau.
U.S. Patent 4,801,175 Albanese shows an example of a furniture
article that provides a convertible bench/table. However the
Albanese structure is not useful as a support platform since it
does not provide a sufficiently stable support for the table top
when in the horizontal position. U.S. Patent 4913488 Donnell
JR. shows another example of convertible furniture which has a
support member rotatably mounted on the frame and movable from a
seat back position to a table top position. However in the
table top position Donnell's support member is clearly unsuit-
able for use as a support platform since is only supported over
a relatively narrow portion in the front to back direction nor
would it provide the desired degree of stability for use as a
support platform. It is believed that few of the prior art
designs have been commercially successful, one possible reason
being that they are inadequately designed or unduly complicated
so as not to be economically viable. Such prior art designs of
convertible bench/tables furthermore lacked stability in the
A(l~Ef~DED S;iEET
CA 02183357 2004-02-03
760'44-5
2
table configuration.
Summary of the Invention
The aim of the present invention is to provide a
multi-purpose convertible furniture article that is of
sturdy and relatively simple construction and that will, in
particular, be stable when used in a table or platform
configuration.
According to one aspect the invention provides an
article of furniture comprising: a substantially rigid base
frame having four feet regularly arranged in longitudinally
aligned front and rear pairs which pairs are spaced
transversely from each other to provide a stable support for
said article upon a horizontal surface, said front pair of
feet being wheels; said frame including longitudinally
spaced sub-frames extending transversely and from top-to-
bottom of said frame, said sub-frames being rigidly
interconnected by vertically and transversely spaced
horizontally extending frame elements and by brace means;
two of said frame elements comprising a pair of
longitudinally spaced horizontal supports each rigidly
attached at transversely spaced locations on said frame and
having end portions projecting transversely beyond a rear
side of said frame; a horizontal seat carried on and
extending between said end portions; said article further
including a table top having a length and a width, said
table top being selectively movable between a horizontal
position wherein said table top is supported on a top
section of said frame, and a lower position wherein said
table top is supported on said frame in a position extending
upwardly from one longitudinal edge of said seat so as to
provide a backrest, guide means interacting between said
CA 02183357 2004-02-03
76044-5
3
table top and said frame to accommodate such movement of the
table top; retainer means selectively operable to secure
said table top in said horizontal position wherein said
table top is transversely offset relative to said seat;
wherein said frame carries support means that extend over a
distance in the front-to-rear direction that corresponds to
a major portion of the width of the table top such that in
the horizontal position the table top is stably supported on
said support means over a major part of the width of said
table top; said article of furniture having a center of
gravity and having a weight distribution such that when said
article of furniture is supported on a horizontal surface
and the weight of a user is concentrated on the front of
said table top, the article of furniture remains stable.
According to another aspect the invention provides
an article of furniture comprising: a substantially rigid
base frame having four feet regularly arranged in
longitudinally aligned front and rear pairs which pairs are
spaced transversely from each other to provide a stable
support for said article upon a horizontal surface; said
frame including longitudinally spaced sub-frames extending
transversely and from top-to-bottom of said frame, said sub-
frames being rigidly interconnected by vertically and
transversely spaced horizontally extending frame elements
and by brace means; two of said frame elements comprising a
pair of longitudinally spaced horizontal supports each
rigidly attached at transversely spaced locations on said
frame and having end portions projecting transversely beyond
a rear side of said frame; a horizontal seat carried on and
extending between said end portions; a table top having a
CA 02183357 2004-02-03
76044-5
3a
length and a width, said table top being selectively movable
between a horizontal position wherein said table top is
supported on a top section of said frame, and a lower
position wherein said table top is supported on said frame
in a position extending upwardly from one longitudinal edge
of said seat so as to provide a backrest; guide means
interacting between said table top and said frame to
accommodate such movement of the table top said guide means
comprising at each end of said frame a longitudinally
extending pivot pin received within a corresponding
transversely extending slot on the underside of said table
top, said pivot pins being substantially coaxial, and said
table top being movable transversely relative to and
pivotable about the axis of said pivot pins; retainer means
selectively operable to secure said table top in said
horizontal position wherein said table top is transversely
offset relative to said seat, said retainer means comprising
retaining pins that are insertable through said slots when
the table top is in its horizontal position, each said
retaining pin being received within a socket in said frame
to inhibit horizontal or pivotal movement of the table top
relative to said frame; wherein said frame carries support
means that extend over a distance in the front-to-rear
direction that corresponds to a major portion of the width
of the table top such that in the horizontal position the
table top is stably supported on said support means over a
major part of the width of said table top; said article of
furniture having a center of gravity and having a weight
distribution such that when said article of furniture is
supported on a horizontal surface and the weight of a user
is concentrated on the front of said table top, the article
of furniture remains stable.
CA 02183357 2004-02-03
7604-5
3b
The furniture article can be made of any suitable
material, but conveniently can be fabricated substantially
entirely from wood. Without requiring the furniture article
to be excessively weighty, it can be configured to provide
the required stability when used as a platform or staging by
arranging the front feet to be positioned more or less
directly below the front edge of the table top. Similarly
the rear feet are positioned directly below or not far
forwardly of the rear edge of the seat so that the furniture
article will not lose its stability even when the user's
weight is concentrated on the rear edge of the seat.
For convenience in moving the article, one or
other of the pair of feet (preferably the rear pair) may
include wheels so that the furniture article can be lifted
at the side opposite where the wheels are located and
readily transported by being rolled on the wheels.
The guide means for the table top is preferably
provided by an elongate slot formed in a stringer that
extends across the width of the underside of the table top
in the front to rear direction, each of these slots
cooperating with a respective pin in the adjacent end of the
base frame in the upper rear area thereof. In the
horizontal position of the table top the pin is received in
one end of the slot so that the table top can be moved
transversely and pivoted into the bench backrest position.
WO 95!21558 ,~ 1 ~ 3 ~ 5 7 PCTlCA95/00069
4
Preferably at each end of the table there is a
retaining pin that, when the table top is in its horizontal
position can be inserted through the forwardmost end of the slot
and engaged in a socket in the adjacent upper front portion of
the base frame to secure the table top against rearward or
pivotal movement. It may be desirable to arrange for the entire
weight of the table top and any load supported thereon to be
transmitted to the base frame through the pivot pins and the
retaining pins.
It is also desirable to include adjustable support
means through which the table top can be supported at various
inclined positions. Such support means could be in the form of
a pivoted link at each end of the table top having a series of
holes therein enabling the retaining pin to be passed through a
selected hole to engage in the base frame socket, so that the
pivoted link then supports the table top at the desired angle of
inclination.
As referred to above, the convertible furniture
article can be configured so that it forms a bench or a table,
and can also be utilized as a support platform, a sawhorse, a
combination work bench, a desk, and indeed for many other
purposes as will occur to the user. If desired, it can be
designed to be collapsible so that it can be disassembled for
shipping or storage.
Numerous features and details of the invention will be
more fully understand from the following description of specific
embodiments, given by way of example only, when read in
conjunction with the accompanying drawings wherein:
W O 95!21558 PCT/CA95/00069
21833 ~~~
Figure 1 is a perspective view, from the rear and one
end, of a preferred embodiment of the convertible furniture
article;
Figure 2 is a perspective view corresponding to Figure
1 showing the furniture article in a modified configuration as
seen in Figure 6;
Figure 3 is a plan view;
Figure 4 is a front elevational view of a second
embodiment, that is modified by the inclusion of wheels at the
lower end of the front legs;
Figure 5 is an end elevational view of the article as
seen from the right hand side of Figure 4;
Figure 6 is a view corresponding to Figure 5 but
showing the furniture article in an altered configuration;
Figure 7 is a view corresponding to Figure 5 showing
the article in yet another configuration;
Figure 8 is an end elevation showing two such
convertible furniture articles juxtaposed to provide a picnic
table;
Figure 9 is an enlarged fragmentary front elevational
view showing a portion of the article as seen in Figure 4; and
Figure 10 is a view corresponding to Figure 9 showing
a modification.
The furniture article 1 comprises a sturdy and rigid
base frame 2 on which is supported a table top 3, and a
longitudinally extending seat 4 that projects rearwardly from
the frame.
The frame may be fabricated of any desired material
WO 95/21558 PCTICA95100069
21~33~?
6
and as shown in the drawings coMprises two vertically oriented
longitudinally spaced sub-frames 5 which are rigidly
interconnected to form the base frame. Each sub-frame 5 is of
generally A-shape as seen in side view comprising a generally
upright front leg 6 and an upwardly and forwardly inclined rear
leg 7, these legs being interconnected by a transverse
horizontal top member 8 near their upper ends and at about mid-
height by a transverse horizontally extending intermediate
member 9, the members 8 and 9 extending in what for convenience
is herein described as the front to rear direction of the
article. The members 8 and 9 are rigidly interconnected to the
legs 6 and 7 by suitable fastening means, as illustrated by
bolts 10.
Each intermediate horizontal member 9 projects
rearwardly of the leg 7 and carries one end of a seat 4 formed
as shown by two timber planks 15 attached as by nailing to the
extensions 11, the outermost plank 15 having centrally therein a
hand grip aperture 16.
As best seen in Figure 4, the end sub-frames 5 are
rigidly interconnected by a longitudinally extending member 17
spaced below the upper ends of the sub-frames, this being
secured to the front legs 6 and reinforced by angularly arranged
braces 18. The top ends of the sub-frames 5 are further
interconnected by longitudinally extending wooden planks 19
screwed to the tops of the legs 6 and 7. In the embodiment of
Figures 1 and 2 the lower ends of the legs provide widely spaced
feet 6a, 7a whereas in the embodiment of Figures 4 to 8 the feet
at the lower ends of the front legs 6 are coaxial pairs of
W O 95121558 PCT/CA95/00069
X183357
wheels 20.
The table top 3 comprises a number of longitudinally
extending wooden planks 22 extending in closely spaced
relationship and interconnected on their undersides at each end
on the outboard side of the adjacent sub-frame 5 by a transverse
stringer 23 extending as seen in Figure 1 in the front to rear
direction, the stringers being wooden members to which the
planks 22 are nailed to provide therewith a rigid table top
structure which has a transverse width in the front to rear
direction (see Figure 4) that only slightly exceeds the width of
the top end of the base frame 2. Each stringer 23 has a
longitudinal through slot 24 therein, this slot having a length
that is only slightly less than the length of the stringer. A
pivot pin 25 mounted in the upper rear corner of each sub-frame
5 projects laterally therefrom and extends through the slot 24
in the adjacent stringer, the pins 25 being coaxial and together
forming a pivot axis for the table top.
Horizontally offset from the pivot pin 25, each sub-
frame 5 has a socket 26 (Figure 6) which is aligned with the
front end of the respective slot 24 and which receives a
retaining pin 27 which can be passed from the outboard side
through the front end of the slot. It will be seen that with
the retaining pin positioned in its socket as illustrated in
Figure 4, the table top is essentially immobilized. In this
position, as shown in Figure 9, the planks 22 of the table top
are spaced slightly above the horizontal planks 19 on top of the
sub-frame, and accordingly the weight of the table top and of
any load supported thereon is transmitted to the base frame
PCT/CA95100069
WO 95121558 J 7
8
through the pivot pins 25 and retaining pins 27. Thus the pins
25 and 27 provide a solid abutment supporting the table top in
its horizontal position and do not rely on any frictional force
in this supporting action. Additionally, the planks of the
table top have only a small clearance above the planks 19 at the
top of the base frame (see particularly Figures 9 and 10) and so
can provide additional support to the table top in the event
that it deflects downwardly in the middle under load.
Additionally, the rigid base frame 2 provides a safety feature
in that in the event of failure of one or more of the pins 25
and 27, the table top will drop only a very short distance
before it once more finds solid support on the planks 19 at the
upper end of the base frame. In practice, the clearance between
the planks 19 and the underside of the table top boards 22 need
be no more than two or three millimetres. The possibility of
failure of any of the pins 25, 27 is quite remote since these
can easily be selected to be of a size and strength sufficient
to support any practical load with a high safety factor.
Furthermore these pins provide an abutment type support for the
stringers 23, and are loaded in shear to which they are highly
resistant. In no sense is there any reliance on gripping or
frictional forces to support the table top 3.
From the foregoing description it will be appreciated
that when the retaining pins are withdrawn, the table top 3 can
be moved transversely to the rear (this movement being
accommodated by the slots 24) and can then be pivoted and moved
downwardly to the position shown in Figures 2 and 6 where the
table top assumes an upwardly and rearwardly inclined attitude
WO 95/21558 ~ ~- PCT/CA95/00069
2183~~?
9
and provides a backrest in relation to the seat 4. In this
backrest position the table top 3 is supported against the upper
rear edge 28 of the rear legs 7, this edge 28 being angulated as
seen in Figure 5 to be somewhat more upright than the direction
of orientation of the leg 7.
When it is required for the table top to be held at a
slight inclination, the retaining pins 27 are withdrawn, the
table top 3 pivoted slightly upwardly at its front end around
the pins 25, and after reinsertion of the retaining pins 27, the
table top is released so that the lower surfaces of the
stringers 23 come to rest on the retaining pins 27. Minor
variations in the inclination can be effected by providing on
the retaining pins 27 an eccentric polygonal cam configuration
(not shown) having a number of facets at different spacings from
the axis of the pin, in use these facets being selectively
oriented to support the lower surfaces of the stringers 23.
Additional or alternative means can be provided for
adjusting the inclination of the table top 3, as shown in Figure
5 this being in the form of an elongate link or strut 29 lying
against the underside of the planks 23 on the outboard side of
each stringer 23 and pivoted to the latter by a pin 30. Each of
the links 29 has a series of longitudinally spaced holes 32 of a
size to accommodate passage of the retaining pin 27. Therefore
when the retaining pin is withdrawn and the table top pivoted
upwardly at its front about the axis of the pins 25, each link
29 can be swung downwardly, and a selected one of its holes
brought into register with the socket 26 whereupon the retaining
pin can be inserted through that hole into the socket, and the
PCTlCA95100069
WO 95/21558
link 29 will form a strut to support the table top at the
desired inclination as illustrated in Figure 7. When not in use
the links 29 are stowed against the underside of the table top
planks 22 and retained thereby suitable means, e.g. springs (not
shown).
Figure 9 shows the interconnection of the pivot pin 25
to the base frame 5. The pivot pin is received in a bore 34 in
the base frame and is secured by a washer 35 and a wing nut 36,
there being a further washer 37 between the head of the pivot
10 pin and the outer side of the stringer 23, the pivot pin passing
with clearance through the slot 24.
Similarly, as seen in Figure 10, the retaining pin 27
passes with clearance through the slot 24 to be received in the
socket 26 formed by a bore in the front leg 6.
From the foregoing it will be appreciated that the
described furniture article is readily convertible from the
table configuration as shown in Figure 1 to the seating
configuration as shown in Figure 2. What is particularly
advantageous about the convertible furniture article of the
present invention is its stability when used as a platform or
staging in the configuration seen in Figures 1 and in 3 to 5.
In this configuration the upper surface of the table top 30 will
be at a height of some 70 to 75 centimetres above the ground
support surface, and may readily be accessed by a user employing
the seat 4 as a step. With reference to Figure 5 it will be
seen that the retaining pins 27 and pivot pins 25 between them
provide a secure attachment and support for the table top upon
the base frame 2, this support extending over the major part of
WO 95121558 218 3 3 ,5 7 PCT/CA95/00069
11
the width of the table top as measured in the front to back
direction.
Furthermore, the furniture article provides a secure
and stable support for a user standing on the table top. Thus
even if the weight of the user is concentrated on the
forwardmost edge of the table top as indicated by the arrow 40
in Figure 5, the article will remain stable so long as the
distance of the arrow 40 forwardly of the vertical plane 41 of
the forwardmost point of contact between the support frame 2 and
the ground, i.e. the location where the wheels 20 contact the
ground, times the weight of the user, is less than the spacing
between the plane 41 and the center of gravity 42 times the
weight of the furniture article 1. In other words the furniture
article will remain stable so long as the following relationship
holds true:
L x D1 > W x D2
where:
L is the load produced by the weight of the user,
W is the weight of the furniture article,
D1 is the spacing between the arrow 40 and the plane
41, and
D2 is the spacing between the center of gravity 42 and
the plane 41.
In comparing Figures 1 and 5 it will be seen that in
the former, the critical plane will coincide with the front of
the feet 6a formed by the lower ends of the front legs 6 whereas
in Figure 5, with the wheels centrally mounted on the front legs
6, the plane 41 is at an intermediate location about midway
WO 95!21558 ~ J 7 PCT/CA95/00069
12
between the front and rear of the feet 6a of front legs 6. Thus
in order to increase the stability of the furniture article it
is preferable to ensure that the wheels 20 contact the ground
surface more or less directly below the front edge of the table
top 3. For this purpose, rather than the wheels being mounted
centrally in the front legs 6, they may be mounted with their
axis in the regions of the forward edge of the front legs (not
shown). Alternatively, the front legs 6 may be angled forwardly
downwardly to achieve the same effect. In the embodiment shown
in Figure 5 the ratio D1 . D2 is in excess of 5 so that the
furniture article can stably support a load at the location of
the arrow 40 of at least 5 times the weight of the furniture
article.
Similarly, as shown in Figure 5, the spacing D3 of the
center of gravity 42 forwardly of the vertical plane defined by
the rear end of the feet 7a is at least 5 times greater than the
spacing D4 from this plane of the rear most part of the seat 4a,
so that this location of the seat can support a load in excess
of 5 times the weight of the bench without tipping. If desired,
the seat could be shortened or the rear feet 7a extended so that
there is no overhang of the seat.
Because of the solid structure of the frame 2 and the
wide based support its provide for both the seat 4 and the table
top 3, the furniture article when in the configuration shown in
Figures 1 or 5 is extremely stable and provides a secure working
platform for the user.
To ensure adequate stability for the article when used
as a platform, the base frame (2) must support the table top (3)
J j ~ PCTlCA95/00069
WO 95/21558
13
or at least half of its transverse (i.e. front to back) width.
Thus, with reference to Figure 5, the horizontal spacing between
the pivot pins (25) and the retaining pins (27) must be at least
50%, preferably 75%, and most preferably from 80% to 90% of the
width of the table top (3). This combined with the wide base
provided between the front and rear legs (6, 7) ensures a very
stable support for the furniture article.
An alternative means (not shown) for adjusting the
inclination of the table tup (3) as discussed in relation to
Figure 7 may be provided by locating elongate support struts
similar to the struts (29) on the inboard side of each stringer
(23). This strut could be of metal or strong plastic of a
thickness about three millimetres, a width of about 2.5
centimetres and a length of about 30 centimetres and pivoted on
a bolt the threaded end of which extends to the outboard side of
the stringer (23) to be engaged by a wing nut by means of which
the link can be pressed against the inboard side of the stringer
(23) to provide a frictional force which will retain the link,
when not in use, in a retracted position where it is hidden by
the stringer (23), but from which it can nonetheless readily be
swung downwardly when it is required to support the table top at
an inclination. This repositioning of the strut from the
outboard to the inboard side of the stringer (23) also has the
advantage that it is now about 6 cm closer to the sub-frame (5)
and can thus more strongly resist lateral movement of the table
top (3).
Another means of preventing or substantially
eliminating lateral movement of the table top (2) when it is
WO 95/21558 L ~ ~ ~ ~ ~ ~ PCT/CA95/00069
14
supported in an inclined condition is to provide a blocking
means (not shown) which can be selectively engaged to prevent
movement of the slot (24) relative to the pivot pin (25). The
blocking means could be in the form of a detent (not shown)
mounted on the stringer (23) and capable of being inserted into
the slot (24) near the rearward end thereof when it is desired
to block movement of the pin (25) lengthwise of the slot (24).
