Socket support and interlock for staging panels

A structural connection for staging panels and the like in which an open-ended socket receives at one end a projection of a structural element such as a leg. The projection has detent projections to be received in a groove in the socket. A locking element is movable into the other end of the socket to engage the detent projections and retain them in the receiving groove until the locking element is retracted.

FIELD OF INVENTION 
Panels and support legs for portable staging used for visiting musical 
groups and choral groups and drama presentations. 
BACKGROUND AND FEATURES OF THE INVENTION 
Reference is made to U.S. Pat. No. 4,638,604, issued Jan. 27, 1987, which 
is directed to the general subject matter of the present invention. 
Portable staging is used to a considerable degree in schools, churches and 
public halls where space is not available for permanent stage 
installations for plays, choral concerts, and popular band concerts. Also 
portable staging is used in gymnasiums or other large halls to enlarge 
existing stage installations or provide raised platforms for performers. 
These stage installations are composed of panels in 2".times.8', 
3'.times.8', or 4'.times.8' rectangles or in square shapes with legs which 
are detachable so that the panels can be stored flat or readily trucked 
from one location to another. Very often unskilled persons, such as high 
school students, may be moving these panels and, accordingly, the panels 
are subject to rough treatment or to being dropped. Thus, the panels 
should have a rugged construction while being as lightweight as possible. 
It is an object of the present invention to provide a portable stage panel 
with especially high impact corner construction since the corners of the 
panels are most vulnerable to damage. 
Another object is the provision of a high impact corner with built-in 
receptacle for leg attachment and detachment. 
A further object is the provision of an attachment system for support legs 
wherein visual inspection will assure a locked-in condition to insure 
safety while the panels are being used. 
The attachment system includes cooperating insertion elements in a corner 
bore to lock the leg elements in position against accidental dislodgment 
while permitting easy assembly and disassembly. 
Other objects and features of the invention will be apparent in the 
following specification and claims in which the invention is described 
together with details to enable persons skilled in the art to practice the 
invention, all in connection with the best mode presently contemplated for 
the invention.

DETAILED DESCRIPTION OF THE INVENTION AND THE MANNER AND PROCESS OF USING 
IT 
With reference first to FIGS. 1 and 2, the corner of a stage panel is 
illustrated in plan in FIG. 1 and in section in FIG. 2. Each panel has a 
top surface element 20 and a bottom surface 22 formed of a compact 
material and overlying and underlying a lightweight honeycomb filler 24. 
These surface elements and the filler are preferably bonded together as a 
unitary structure. 
Around the edge of the panel are molded or extruded side plates 30 
preferably formed of aluminum and shown in vertical section in FIG. 2. 
Each side plate has an outer wall surface flanged at top 32 and bottom 34 
and open at 36 to provide an elongate passage which opens to a re-entrant 
groove 38 in front of a back wall 40. Inner flanges 42 have serrated outer 
surfaces 44 which cooperate in retaining the side plates in the panel 
construction. 
The corner construction in FIG. 1 includes a square aluminum or plastic 
molding or extrusion block 50 which has sides 52 connected by webs 54 to a 
cylindrical wall 56 which has an axial recess 60. 
At the corner of the block 50 where the two side plates converge are 
parallel webs 62 which are integral with converging sides 52 and with an 
outer corner pillar 64, which has top and bottom ends which are flush with 
the outer surfaces of the top and bottom surface elements 20, 22. These 
surface elements overlie the remainder of the block 50, that is, the sides 
52 and webs 54, 62. The pillar 64 has wing tabs 66 and 68 shaped and 
dimensioned to enter the re-entrant groove 38,38 so the corner block is 
securely established as an integral part of the panel, locked into the two 
side extruded plates 30 and between the top and bottom surface elements 20 
and 22. 
Thus, any corner impact on the panel will be resisted by the block 50 and 
the pillar 64 which are solidly mounted between the top and bottom 
surfaces 20, 21 and the side plates 30. 
In FIGS. 3 and 4, a modified impact corner is illustrated. Reference 
characters applied to FIGS. 1 and 2 are applied to similar parts in FIGS. 
3 and 4. The corner insert is, in this case, shaped like a trapezium with 
two forward walls 80 at right angles to each other and two rearwardly 
extending walls 82 merging in a rounded surface 84 inside of which is a 
cylindrical opening 86. The corner pillar 90 is formed at the juncture of 
walls 80, and webs 92 reinforce the entire structure. The pillar 90 
extends above and below the general plane of the insert at 94 and 96. Side 
wings 98 cooperate with the re-entrant grooves 38 in the panel side plates 
30. 
The high impact corners illustrated in FIGS. 1 to 4 also serve to support 
the panels at the corners. As illustrated in FIGS. 5 and 6, a support leg 
99 will be securely attached to a flanged conical projection 100 having a 
central bore 101 and a bottom flange 102 and also a depending shaft 104 
which is embedded in the support leg. The support legs may have a series 
of two or four spaced projections to engage adjacent panels in an extended 
stage array. Each conical projection 100 has recessed opposed detent balls 
110 to cooperate with a receiving socket 120 having a cylindrical bore 60. 
This socket can either be cast into the impact corner as in FIGS. 1 and 2 
or inserted and retained in the cylindrical recess 86 of FIGS. 3 and 4. 
The receiving socket bore 60 has two axially spaced, annular grooves 122 
and 124. As shown in FIG. 7, a top plug insert 130 shown diagrammatically 
is generally cylindrical in shape and has embedded in the lower end a 
metal pin 132 with a tapered end 134. The top of the insert has a central 
hole 136 and side bores 138. 
In FIG. 8, a looped hook tool 139 has a toe portion 139A which can be 
inserted in hole 136 and a bore 138 to lift the insert 130. 
Referring again to FIG. 7, there are resilient projections 140 and 142 on 
the outer surface of insert 130 which will provide an interference fit in 
the socket bore 60. These projections will engage the upper groove 122 to 
position and retain the insert in the bore when the panel is not in an 
operative position. 
In FIG. 9, an elevation of an actual operative insert 130 is shown. The 
insert is basically cylindrical and has a steel pin 132 mounted centrally 
in one end. The opposite end has a central opening 136 to receive the toe 
end 139A of retraction tool 139 (FIG. 8). An oblong passage 150 extends 
through the insert intersecting the central hole 136. This passage 
accommodates the toe 139A of the tool 139 to allow lifting of the insert. 
Elongate side openings 151, FIGS. 9 and 10, separated by a web 152, are 
non-functional but provided to lighten the insert and save material. As 
viewed in FIG. 9, there are opposed, axially spaced, chordal cored 
openings 154 separated by webs 156. Extending axially from each of these 
webs 156 are chordal projections 140 and 142 connected to the webs 154 by 
resilient neck portions 158. The projections 140, 142 are rounded in both 
the axial and transverse dimension (FIGS. 9 and 10) to cooperate with 
annular grooves 122 and 124 in the socket recess 60 of socket 120. 
IN THE OPERATION of the described structure, in the storage position of a 
panel, the plug insert 130 can be in the upper position as shown in FIG. 6 
where projections 140 engage groove 122. In this position the insert is 
retained against dislodgment and protected from accidental contact. The 
depending pin 132 is confined in the lower portion of the recess 60. If 
desired, the insert 130 can be moved to the lower position prior to 
assembly to facilitate insertion of the pin 132 into the opening 101 in 
cone 100. 
When a support leg core 100 is projected into recess 60, the pin 132 will 
enter the central bore 101 of the core and position near the detent balls 
110. The conical end 134 of pin 132 is intended to cam the balls 110 
outward into the annular groove 124 in bore 60. If this camming is not 
immediate, the top insert 130 will be forced up out of bore 60 a short 
distance to project above the surface 20 of the panel. This will alert an 
assembler that the pin 132 is not seated and he or she can step on the 
insert 130 to force the conical point 134 between the balls 110 to lock 
the leg in the socket 60. In this position the projections 140 of the 
insert will engage the upper groove 122 and both the cone 100 and the 
insert 130 are locked in position in the bore recess 60. 
To release a leg from a panel corner, the tool 139 (FIG. 8) is used. The 
toe 139A of the tool is inserted into the passage 136 and hooked into a 
bore 138 (FIG. 7) or a recess 150 (FIG. 9). An upward force on the tool 
139 pulls the insert 130 up, removing the pin 132 from between the detent 
balls 110. This permits the release of the cone 100 from the lower end of 
the bore 60. In this position, the detent projections 142 on the insert 
130 can engage the upper groove 122 to retain the insert in place. After 
the removal of the support leg, the insert may again be pressed flush with 
the panel top, thus engaging detent projections 140 with upper groove 122 
so the insert is secured against dislodgment during the transportation or 
storage phase. 
In addition to support legs, the attachment structure above described may 
be used to connect railing stanchions and other elements of a staging 
system. 
It will be appreciated that the projection 132 not only actuates the 
detents 110 but also serves as a stabilizing element in being received in 
the central recess of the leg cone 100. Together, the cone 100 and the 
insert 130 are joined in a combined unit filling the bore 60 and resisting 
any lateral movement of the support leg or other element secured to the 
cone 100. 
The projection 132, while shown in full lines in FIGS. 7 and 9, is shown in 
dotted lines in FIGS. 5 and 6 to indicate that it is optional and that the 
upper plug insert 130 can be used without the projection 132 in some 
installations. When the lower insert 100 is provided with detents 110 
which are spring biased outwardly, the projection 132 is not needed to 
insure detent engagement and the upper plug 130 is used to fill the upper 
portion of the recess 60. Similarly, the integral detent projections 140 
and 142 of FIGS. 9 and 10 will serve the same function as detents 110.