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Claims  |
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What is claimed is:
1. A folding framework for use as a folding display frame movable between
an open expanded position forming a three-dimensional array of cubicles in
a display-supporting frame and a compact closed form for storage, the
framework comprising:
a plurality of pairs of rods, each pair of rods being pivotally joined to
each other at an intermediate point;
a plurality of hubs, the respective ends of each rod being pivotally joined
to corresponding ones of said hubs, each hub having a plurality of said
rods pivotally joined thereto;
the pivotal connection of each rod to a hub providing rotation of the rod
relative to the hub about a corresponding single axis of revolution;
rods connected to any one hub being rotatable about said single axis of
revolution from a closed position in which all the rods are substantially
parallel to each other to an open position in which the rods radiate
outwardly from each other;
each hub having a base plate with fixed flanges projecting therefrom for
pivotally supporting a first pair of said rods secured to a corresponding
first pair of said flanges on opposite sides of a central axis of the hub
and a second pair of said rods pivotally connected to a corresponding
second pair of said flanges on opposite sides of the central axis of the
hub, said second flanges extending substantially perpendicularly to said
first flanges;
the pair of first flanges having corresponding fixed first bearing surfaces
lying substantially on a first axis passing essentially through the
central axis of the hub, the pair of second flanges having corresponding
fixed second bearing surfaces lying substantially on a second axis passing
essentially through the central axis of the hub and extending
substantially perpendicularly to said first axis;
the ends of the first rods pivotally secured to said first bearing surfaces
being rotatable thereon about spaced apart fixed axes of revolution
extending substantially parallel to each other and lying substantially in
a first plane, the ends of the second rods pivotally secured to said
second bearing surfaces being rotatable thereon about spaced apart fixed
axes of revolution extending substantially parallel to each other and
lying substantially in a second plane which is spaced outwardly from the
base plate by an offset distance greater than said first plane and which
lies substantially parallel to the first plane.
2. Apparatus of claim 1 wherein all the rods are of substantially equal
length and each rod is connected at one end at a pivotal connection in
said first plane of the associated hub and is connected at the other end
at a pivotal connection in said second plane of the associated hub.
3. Apparatus of claim 1 wherein the rods are of a first length or a second
length, the difference in length being twice the distance between said
first and second planes.
4. Apparatus of claim 1 wherein, in said open position, the rods connected
to each hub extend outwardly substantially perpendicularly to each other,
whereby the rods and associated hubs form a rectangular lattice.
5. Apparatus of claim 2 wherein, in said open position, the rods connected
to each hub extend outwardly substantially perpendicularly to each other,
whereby the rods and associated hubs form a substantially square shaped
lattice.
6. Apparatus of claim 3 wherein, in said open position, the rods connected
to each hub extend outwardly substantially perpendicularly to each other,
whereby the rods and associated hubs form a rectangularly shaped lattice.
7. Apparatus of claim 1 further including stab connector means mounted on
at least one pair of hubs, the stab connector means including a male
member rigidly mounted on and projecting from one of said pair of hubs,
and a female member rigidly mounted on and projecting from the other of
said pair of hubs, the male and female members telescopically engaging
when the hubs are moved into the open position of the folding frame, and a
releasable catch on one of said members engaging the other of said members
to lock the telescopically engaged members together.
8. Apparatus of claim 1 in which the rods are tubular metal rods with an
outside diameter approximately one half the width of the hub.
9. Apparatus of claim 1 in which the second pair of flanges project
outwardly from the base plate of the hub by an extended distance in which
the second plane is at least twice the distance from the base plate than
the first plane, whereby the framework can be moved to an open position
defining a short radius of curvature.
10. Apparatus of claim 9 in which the pair of second flanges includes
multiple pivot points to which the second rods can be selectively attached
on each second flange, said pivot points on each flange comprising spaced
apart holes on each second flange progressing outwardly from the base
plate.
11. Apparatus of claim 1 wherein the spacing between the first and second
flanges allows each base plate to be sufficiently compact in size while
its folded rods avoid interference with each other sufficiently so that
the hubs can nest against each other in the closed condition of the
framework.
12. Apparatus of claim 1 wherein the rods pivotally attached to the first
flanges of each hub are longer than the rods pivotally attached to the
second flanges of each hub, to thereby form a rectangular lattice.
13. Apparatus of claim 1 wherein the rods pivotally attached to the first
flanges of a first hub are pivotally secured at their opposite ends to
corresponding second flanges of a second hub, and in which the rods
pivotally attached to the second flanges of a first hub are pivotally
secured at their opposite ends to corresponding first flanges of said
second hub, to thereby form a substantially square shaped lattice in the
open condition of the framework.
14. Apparatus of claim 1 in which the first flanges are offset from one
another on opposite sides of the central axis, and the second flanges are
offset from one another on opposite sides of the central axis.
15. In a folding open framework for use as a folding display frame movable
between an open expanded position forming a three-dimensional array of
cubicles in a display-supporting frame and a compact closed form for
storage, the framework comprising a plurality of pivotally joined pairs of
rod members in which four of said pairs of rod members are pivotally
joined at their ends by eight hub members to form four sides of a
rectangular cubicle having a hub at each of the eight corners of the
cubicle, a plurality of said cubicles forming an array with adjoining
cubicles sharing a common pair of rod members and the associated four hub
members at each of the ends of the pair of rod members, the improvement
comprising:
each hub member having a base plate with fixed flanges projecting therefrom
for supporting a first pair of said rod members pivotally secured to a
corresponding first pair of flanges on opposite sides of a central axis of
the hub and a second pair of said rod members pivotally secured to a
corresponding second pair of said flanges on opposite sides of the central
axis of the hub, said second flanges extending substantially
perpendicularly to said first flanges;
the pair of first flanges having corresponding fixed first bearing surfaces
lying substantially on a first axis passing essentially through the
central axis of the hub, the pair of second flanges having corresponding
fixed second bearing surfaces lying substantially on a second axis passing
essentially through the central axis of the hub and extending
substantially perpendicularly to the first axis;
the ends of the first rod members pivotally secured to the first bearing
surfaces being rotatable thereon about spaced apart fixed axes of
revolution extending substantially parallel to each other and lying
substantially in a first plane, the ends of the second rod members
pivotally secured to said second bearing surfaces being rotatable thereon
about spaced apart fixed axes of revolution extending substantially
parallel to each other and lying substantially in a second plane which is
spaced outwardly from the base plate by an offset distance greater than
said first plane and which lies substantially parallel to said first
plane.
16. Apparatus of claim 15 wherein the rod members pivotally attached to the
first of said hub flanges are longer than the rod members pivotally
attached to the second of said hub flanges, the difference in length being
equal to twice the amount of offset of the associated axes of revolution.
17. The apparatus of claim 15 wherein the rod members are all of
substantially equal length.
18. Apparatus of claim 15 further including stab connector means mounted on
at least one pair of hubs, the stab connector means including a male
member rigidly mounted on and projecting from one of said pair of hubs and
a female member rigidly mounted on and projecting from the other of said
pair of hubs, the male and female members telescopically engaging when the
hubs are moved into the open position of the folding frame, and a
releasable catch on one of said members engaging the other of said members
to lock the telescopically engaged members together.
19. Apparatus of claim 15 wherein the hubs on at least one side of the
framework include a flanged knob projecting therefrom, a bar having a
plurality of keyslots spaced along the bar at intervals corresponding to
the distance between knobs, for engaging the knobs of aligned hubs,
whereby the bar is removably secured to a plurality of hubs, each
successive keyslot being shorter in length than the adjacent keyslot,
whereby the bar can be engaged one knob at a time to the aligned hubs.
20. Apparatus of claim 19 wherein the bar includes a plurality of sections
and hinge means securing each section to an adjacent section, whereby the
bar can be folded when not secured to the knobs.
21. Apparatus according to claim 20 in which the hinge means have
adjustable friction means for controllably adjusting the friction of the
hinge joint about with the sections of the bar fold.
22. Apparatus of claim 15 in which the spacing between the first and second
flanges allows each base plate to be sufficiently compact in size while
its folded rod members avoid interference with each other sufficiently so
that the hubs can nest against each other in the closed condition of the
framework.
23. Apparatus of claim 15 wherein the rod members pivotally attached to the
first flanges of each hub are longer than the rod members pivotally
attached to the second flanges of each hub to form a rectangular lattice.
24. Apparatus of claim 15 wherein the rod members pivotally attached to the
first flanges of a first hub are pivotally secured at their opposite ends
to corresponding second flanges of a second hub, and in the rods pivotally
attached to the second flanges of a first hub are pivotally secured at
their opposite ends to corresponding first flanges of said second hub to
form a substantially square shaped lattice in the open configuration of
the framework.
25. Apparatus of claim 15 in which the first flanges are offset from one
another on opposite sides of the central axis, and the second flanges are
offset from one another on opposite sides of the central axis.
26. Apparatus of claim 15 in which the rods are tubular metal rods with an
outside diameter approximately one half the width of the hub.
27. Apparatus of claim 15 in which the second pair of flanges project
outwardly from the base plate of the hub by an extended distance in which
the second plane is at least twice the distance from the base plate than
the first plane, whereby the framework can be moved to an open position
defining a short radius of curvature.
28. Apparatus of claim 27 in which a pair of second flanges includes
multiple pivot points to which the second rods can be selectively attached
on each second flange, said pivot points on each flange comprising spaced
apart holes on each second flange progressing outwardly from the base
plate.
29. A folding framework for use as a folding display frame movable between
an open expanded position forming a three-dimensional array of
compartments in a display-supporting frame and a compact closed form for
storage, the framework comprising:
a plurality of pairs of rods, each pair of rods being pivotally joined to
each other at an intermediate point;
a plurality of hubs, the respective ends of each rod being pivotally joined
to corresponding ones of said hubs, each hub having a plurality of said
rods pivotally joined thereto;
the pivotal connection of each rod to a hub providing rotation of the rod
relative to the hub about a corresponding single axis of revolution;
rods connected to any one hub being rotatable about said single axis of
revolution from a closed position in which all the rods are substantially
parallel to each other to an open position in which the rods radiate
outwardly from each other;
each hub having a base plate with fixed flanges projecting therefrom for
pivotally supporting a first pair of said rods secured to a corresponding
first pair of said flanges on opposite sides of a central axis of the hub
and a second pair of said rods pivotally connected to a corresponding
second pair of said flanges on opposite sides of the central axis of the
hub, said second flanges extending at an angle to said first flanges;
the pair of first flanges having corresponding fixed first bearing surfaces
lying substantially on a first axis passing essentially through the
central axis of the hub, the pair of second flanges having corresponding
fixed second bearing surfaces lying substantially on a second axis passing
essentially through the central axis of the hub and extending at said
angle to said first axis;
the ends of the first rods pivotally secured to said first bearing surfaces
being rotatable thereon about spaced apart fixed axes of revolution
extending substantially parallel to each other and lying substantially in
a first plane, the ends of the second rods pivotally secured to said
second bearing surfaces being rotatable thereon about spaced apart fixed
axes of revolution extending substantially parallel to each other and
lying substantially in a second plane which is spaced outwardly from the
base plate by an offset distance greater than said first plane and which
lies substantially parallel to the first plane.
30. Apparatus of claim 29 in which the second pair of flanges project
outwardly from the base plate of the hub by an extended distance in which
the second plane is at least twice the distance from the base plate than
the first plane, whereby the framework can be moved to an open position
defining a short radius of curvature.
31. Apparatus of claim 30 in which the pair of second flanges includes
multiple pivot points to which the second rods can be selectively attached
on each second flange, said pivot points on each flange comprising spaced
apart holes on each second flange progressing outwardly from the base
plate.
32. Apparatus of claim 29 wherein the hubs on at least one side of the
framework include a flanged knob projecting therefrom, a bar having a
plurality of keyslots spaced along the bar at intervals corresponding to
the distance between knobs, for engaging the knobs of aligned hubs,
whereby the bar is removably secured to a plurality of hubs, each
successive keyslot being shorter in length than the adjacent keyslot,
whereby the bar can be engaged one knob at a time to the aligned hubs.
33. Apparatus of claim 32 wherein the bar includes a plurality of sections
and hinge means securing each section to an adjacent section, whereby the
bar can be folded when not secured to the knobs.
34. Apparatus according to claim 33 in which the hinge means have
adjustable friction means for controllably adjusting the friction of the
hinge joint about with the sections of the bar fold. |
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Claims |
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Description |
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FIELD OF THE INVENTION
This invention relates to folding display frames, and more particularly, to
a hub design for interconnecting pivotally joined rods into a folding
frame.
BACKGROUND OF THE INVENTION
Folding display frames are commonly used at trade shows for holding display
panels assembled into a temporary display stand. Photomural displays and
other graphics, projection screens, product display shelves, and the like
are commonly mounted on the portable display stands.
Folding display frames typically comprise a number of rigid frame members
pivotally connected together at their ends in a collapsible and portable
form. The framework, in its expanded or open state, commonly consists of a
grid of horizontal and vertical rod members forming an array of cubicles.
The frame is carried to the exhibition hall in its collapsed form and is
then erected to form the rigid structural framework for the display stand.
Display panels, which are mounted to the display frame, and other
structural members of the supporting frame also are carried to the trade
show in a compact form. The entire folding display system is then
assembled into the finished display unit. When the trade show is
completed, the display frame is collapsed and the display system is
carried away in its portable form.
In a typical three-dimensional framework, a plurality of rod members are
pivotally connected together to permit collapsing of the framework into a
compact form in which the rod members lie substantially parallel to each
other. Except where the framework is assembled in a substantially
permanent structure, the rod members are pivotally joined at their ends to
some type of hub, so that the rods can be rotated relative to each other
as the framework is adjusted between its open, expanded configuration and
its closed, compact storage configuration. Examples of such prior art
folding frameworks are found in U.S. Pat. No. 4,471,548, Goudie; U.S. Pat.
No. 4,479,340, Alphonse, et al.; U.S. Pat. No. 4,512,097, Zeigler; U.S.
Pat. No. 4,580,375, Nodskov, et al.; and U.S. Pat. No. 4,276,726, Derus.
One of the objectives in designing folding display frames is to make the
structure light in weight and compact in its folded form to enhance ease
of transportation and storage when the framework is not in use. At the
same time, the framework, when fully expanded into its useful
configuration, must be strong and fairly rigid. The framework not only
must be strong enough to give adequate support to the display panels and
the items mounted on them, but it must also withstand abuse, particularly
when being constantly folded and unfolded.
Large diameter thin-walled metal tubes normally provide maximum
strength-to-weight ratios. However, the hubs to which the tubes are
pivotally joined must be made light and compact to reduce the space
required by the hubs when they are brought together in the collapsed
configuration of the framework. In the past, attempts to utilize small
hubs and thin solid rods have resulted in a relatively fragile structure,
whereas use of larger diameter tubular rods has resulted in bulkier and
heavier hubs.
A commonly used display frame configuration is one in which the upright
frame has a curved configuration, i.e., the frame is arcuate in the top
plan view shape of the expanded frame. Such a configuration tends to be
more stable than an expanded display frame in a flat form. Therefore, it
is desirable for the portable display frame to be quickly and easily
assembled into a stabilized curved configuration and then be easily
collapsed from this configuration without difficulty.
Display booth spaces rented in exhibition halls are generally of standard
sizes; a standard trade show booth is ten feet wide, for example. As a
result, the folding display frames are commonly assembled into an expanded
configuration which stays within the standard ten-foot-wide space.
However, the designs of prior art portable display frames tend to limit
the configurations of the display stands which are able to fit within the
standard booth space.
Thus, there is a need for a simple, lightweight, strong and rigid folding
display frame which can be quickly and easily unfolded and assembled into
an expanded configuration used in supporting various types of display
stands at trade shows. The display frame also should be easily expanded
into the desired, curved, stabilized configuration normally used in trade
show display stands. The frame also should be quickly and easily folded
into its compact configuration when not in use. The particular
configuration in which the display frame is used should not interfere with
ease of folding the framework into its compact form. The configuration of
the display frame also should not require a large volume or weigh too much
when the frame is folded, since these folding frameworks must be
conveniently transported to and from the exhibition hall.
SUMMARY OF THE INVENTION
This invention is directed to an improved folding framework incorporating a
unique hub design that permits large-diameter, thin-walled tubes to be
pivotally connected in a strong, rigid joint. At the same time, the hub is
very compact and light in weight. In addition to producing a framework
which is strong and rigid in its expanded form, the framework easily
unfolds and folds into a lightweight, compact form. An added advantage of
the present hub design is that it allows rod members of unequal length to
be incorporated into the framework's array so that the height of the array
may be, for example, less than the width while still permitting the
structure to be folded effectively.
Briefly, one embodiment of the framework incorporating features of the
present invention, in its expanded or open state, consists of a grid of
horizontal and vertical rod members forming an array of cubicles, each
cubicle having a top, bottom and two side frame sections. Each frame
section consists of two rods or tubes pivotally joined to each other
midway between their ends. The rods terminate at each end in pivotally
attached hubs. Adjacent cubicles in the array share common rods and hubs.
In the framework's collapsed or closed state, the rods of each frame
section are rotated with respect to each other approximately 180.degree.
so that the opposite ends are brought into proximity. The hubs are then
closely packed in two groups at opposite ends of the substantially
parallel rods. This configuration allows the framework to be easily
expanded into its open configuration and easily collapsed into its compact
configuration.
Each hub is uniquely formed with a base and integrally formed flanges
projecting from the base, the flanges being mutually perpendicular to each
other. A tubular rod is pivotally attached at each end to a hub flange.
The pivot axes of tubes secured to one pair of diametrically opposite
flanges are parallel and lie in a first common plane, and the pivot axes
of the tubes secured to the other pair of diametrically opposite flanges
also are parallel, but lie in a second common plane that is parallel to,
but offset from the first plane. This provides a "high" and "low" hub
configuration of sufficiently compact size that the frame members can be
folded into proximity with the hubs moved together as close as possible in
a two dimensional array, while the folding rods avoid interference during
rotation to allow the framework to be folded into an extremely compact
size. The "high" and "low" hub configuration also allows folding into this
compact size while the frame is constructed from tubular rods of
large-diameter, thin-walled construction that provide maximum
strength-to-weight ratios. Therefore, the hub construction allows folding
into the contact size without sacrificing the rigidity and strength of the
overall framework.
As a further advantage provided by the "high" and "low" hub configuration,
the folding display frame can be expanded into a variety of predetermined
configurations. In one embodiment, a combination of rod members of
different lengths attached to different short or long flanges of the hub
makes it possible to form either a square lattice construction or a
rectangular lattice construction. In a further embodiment, hub length can
be extended to provide different points of pivotal attachment of the rod
members to the hub, so that different combinations of rod member lengths
and pivot points on the hub can produce a variety of display frame
configurations. One advantage of this embodiment is that various display
stand configurations can be produced while the finished display stand
still fits within the confines of the standard ten-foot-wide display booth
size.
These and other aspects of the invention will be more fully understood by
referring to the following detailed description and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a display frame in an expanded position.
FIG. 2 is a top plan view of the expanded frame.
FIG. 3 is a top plan view of a frame hub.
FIG. 4 is a side elevational view of the frame hub.
FIG. 5 is a front elevational view taken on line 5--5 of FIG. 3.
FIG. 6 is a partial view, in perspective, showing a the frame latching
mechanism.
FIG. 7 is a detailed partial view of the frame in a nearly collapsed
position.
FIG. 8 is a detailed partial view similar to FIG. 7 but showing an
alternate construction.
FIG. 9 is a perspective view showing the frame in the folded or collapsed
position.
FIG. 10 is a detailed plan view of a folding channel bar.
FIG. 11 shows the channel bar in its folded condition.
FIG. 12 is an elevational view illustrating an alternative configuration of
the frame hub.
FIG. 13 is an elevational view taken in line 13--13 of FIG. 12.
FIG. 14 is an end elevational view taken on line 14--14 of FIG. 12.
FIG. 15 is a semi-schematic plan view illustrating a standard configuration
of an expanded frame using the hub design illustrated in FIGS. 3 through
5.
FIG. 16 is a semi-schematic plan view illustrating an alternative
configuration of an expanded frame but using the hub design of FIGS. 3
through 5.
FIG. 17 is a semi-schematic plan view illustrating a further alternative
configuration of an expanded frame, using the hub design of FIGS. 3
through 5 but in a different arrangement of hub positions and frame member
connections.
FIG. 18 is a semi-schematic plan view illustrating an alternative
configuration of a display frame using the hub design of FIGS. 12 through
14.
FIG. 19 is a semi-schematic plan view illustrating a further alternative
display stand configuration using the hub design of FIGS. 12 through 14.
FIG. 20 is a fragmentary top plan view, partly in cross-section, showing an
alternative embodiment of a folding channel bar.
FIG. 21 is a fragmentary front elevational view, partly in cross-section,
taken on line 21--21 of FIG. 20.
FIG. 22 is a detailed top plan view illustrating the folding channel bar in
its folded configuration.
DETAILED DESCRIPTION
Referring to FIG. 1, the numeral 10 indicates generally a folding framework
shown in its open or expanded position. The framework is constructed from
multiple pairs of rods or frame members in the form of thin-walled metal
tubes, such as indicated at 12 and 14. The rods in each pair are pivotally
joined together by a hinge pin 16. The hinge pins 16 are located between
the ends of the rods, allowing the rods to swivel with respect to each
other in scissors-like fashion. These rod pairs are joined to form a
grid-like framework, with the multiple pairs of rods being arranged in
vertical columns and horizontal rows. The ends of the rods are joined by a
plurality of identical hubs 18.
As best shown in FIGS. 1 and 2, the framework in the expanded or open
position comprises a plurality of vertical columns, five of which are
indicated respectively at 20, 22, 24, 26 and 28. These are joined by a
plurality of horizontal rows, four of which are indicated at 30, 32, 34
and 36. Each of the rows, as best shown in the top view of FIG. 2, is made
up of pairs of rods 12 and 14 in which the hinge pin pivot connection 16
is located slightly off the center or mid-position between the ends of its
respective rods. Since all horizontal rods are of equal length, this
causes the four pairs of rods joined in each row to assume a slightly
arcuate shape. This shape gives more stability to the frame when resting
on the floor or some other supporting surface.
The rod and hub configuration allow the folding display frame to move
between the open expanded position and a compact closed form for storage.
In the open expanded position, the framework forms a three-dimensional
array of framelike compartments of polygon form which, in the illustrated
embodiment, are formed as cubicles with respective hubs at the corners of
the cubicles. The respective ends of each rod are pivotally joined to
corresponding ones of the hub and each hub has a plurality of the rods
pivotally joined to it. The pivotal connection of each rod to a hub
provides rotation of the rod relative to the hub about a corresponding
single axis of revolution. The rods connected to any one hub are rotatable
about the single axis of revolution from a closed position in which all
rods are substantially parallel to each other to an open position in which
the rods radiate outwardly from each other. Each hub has a base plate with
fixed flanges projecting from it for pivotally supporting a first pair of
rods secured to a corresponding first pair of flanges on opposite sides of
the central axis of the hub and a second pair of rods pivotally connected
to a corresponding second pair of flanges on opposite sides of the central
axis of the hub, in which the second flanges extend substantially
perpendicularly to the first flanges in the configuration in which the
compartments of the frame are formed as cubicles. The pair of first
flanges have corresponding fixed first bearing surfaces lying
substantially on a first axis passing essentially through the central axis
of the hub. The pair of second flanges have corresponding fixed second
bearing surfaces lying substantially on a second axis passing essentially
through the central axis of the hub and extending substantially
perpendicularly to the first axis, in the configuration in which the
compartments are formed as cubicles. The ends of the first rods, pivotally
secured to the first bearing surfaces, are rotatable thereon about spaced
apart fixed axes of revolution extending substantially parallel to each
other and lying substantially in a first plane. The ends of the second
rods, pivotally secured to the second bearing surfaces, are rotatable
thereon about spaced apart fixed axes of revolution extending
substantially parallel to each other and lying substantially in a second
plane which is spaced outwardly from the base plate by an offset distance
greater than the first plane and which lies substantially parallel to the
first plane. This configuration of expandable and contracting cubicles in
the framework provides a number of improvements in folding display frames
described below, and although the invention is described with respect to
the framework being formed with an array of cubicles, other geometric
forms also are possible without departing from the scope of the invention.
The framework is locked in the expanded position shown in FIGS. 1 and 2 by
a suitable latch mechanism which anchors one or more pairs of adjacent
hubs 18' and 18" together. A preferred latch for this purpose is shown in
detail in FIG. 6. One hub of the pair, such as indicated at 18', has a
latch rod 40 which projects toward the adjacent hub 18" of the pair. As
the framework is expanded to its open position by moving the
pairs of hubs 18' and 18" toward each other, the latch rod 40 engages a
latch receptacle which is rigidly secured to the hub 18". The latch rod 40
enters a hole or bore 44 in the end of the latch receptacle 42 where the
tapered end 46 of the rod 40 engages a spring-loaded latch pawl 48. As the
latch rod is fully inserted into the bore 44, the latch rod pawl engages a
notch 50 in the rod, securely locking the rod 40 in position in position
in the latch receptacle 42. The pawl, which is pivotally supported on the
receptacle by a pin 52 can be disengaged from the notch 50 to release the
latch by pushing down on the opposite end 54 of the latch pawl 48. The
pawl is urged into engagement with the notch 50 by a suitable spring 51.
The latch mechanism shown in FIG. 6 need only be provided for one pair of
hubs, preferably near the center of the framework grid. If greater
rigidity is required, additional pairs of hubs can be provided with such a
latch mechanism.
With the latch mechanism released, the entire framework can be collapsed or
folded into the storage condition, as shown in FIG. 9. In this position
the two rods 12 and 14 in each pair of such rods are rotated relative to
each other about the connecting pivot 16, allowing each respective pair of
hubs 18' and 18" to be moved apart until the rods 12 rotate almost 180
degrees relative to the other rods 14 of each pair. In the fully folded
position, all the hubs 18' move into side-by-side engagement with each
other, and all the hubs 18" also move into engagement with each other. In
this way, the hubs are nested in two groups, each group occupying an area
which is limited by the size of the hubs.
In order to achieve nesting in the minimum space and to make the folded
framework as compact as possible, a unique hub is provided which allows
the hub to be substantially reduced in size without sacrificing rigidity
and strength of the framework. At the same time, the hub design of the
present invention provides for ease of assembly in pivotally attaching the
rods to the hubs. Details of the hub design are shown more clearly in
FIGS. 3-5.
Referring to these figures, the hub 18 is preferably molded of a suitable
plastic material, but it can be die-cast or otherwise formed of light
weight metal. The hub is formed with a base plate 60 which is generally
square in outline with the corners rounded as shown in FIG. 5 The base
plate has a flat outer surface 62 from which proj | | |
