Structural steel clamped joint

A joint for structural steel is provided which connects a pair of parallel beams in end-to-end relationship with a second pair of parallel beams. The beams are of any cross-sectional form having an L-shaped component, for example an inverted "S." The beams are retained in a U-shaped channel having two upstanding side walls and a bottom wall connecting the side walls. The bottom wall is provided with one or more centrally located holes. The joint is formed by nesting two pairs of parallel beams in end-to-end relationship within the U-shaped channel. The width of the channel is such that the seating bases of the L-shaped beams do not obstruct the holes in the bottom wall of the U-shaped channel. A clamping plate having holes aligning with the holes of the bottom wall of the channel is fitted into the channel over the seating bases of the beams. Means, such as a nut and bolt, are used to bind the clamping plate onto the U-shaped channel. The clamping plate thereby pushes the beams outwardly against the side walls of the U-shaped channel and downwardly against the bottom wall of the channel.

BACKGROUND OF THE INVENTION 
This invention relates to a system for connecting structural beams in an 
end-to-end relationship. 
It is known to connect a single "T" or "I" shaped beam end-to-end to a 
second beam by drilling holes into the beams and using nuts and bolts to 
join them. This is undesirable as weak spots are formed at the loci of the 
holes. An alternate method involves welding the beams together. This 
operation requires a skilled worker and provides a joint which is not 
easily disassembled if desired. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a joint for structural steel is 
provided which connects a pair of parallel beams in end-to-end 
relationship with a second pair of parallel beams. The beams are L-shaped 
or of any cross-sectional form having an L-shaped component, for example 
an inverted "S". The beams are retained in a U-shaped channel having two 
upstanding side walls and a bottom wall connecting the side walls. The 
bottom wall is provided with one or more centrally located holes. 
The joint is formed by nesting two pairs of parallel beams in end-to-end 
relationship within the U-shaped channel. The width of the channel is such 
that the seating bases of the L-shaped beams do not obstruct the holes in 
the bottom wall of the U-shaped channel. A clamping plate having holes 
aligning with the holes of the bottom wall of the channel is fitted into 
the channel over the seating bases of the beams. Means, such as a nut and 
bolt, are used to bind the clamping plate onto the U-shaped channel. The 
clamping plate thereby pushes the beams outwardly against the side walls 
of the U-shaped channel and downwardly against the bottom wall of the 
channel. 
This joint is particularly useful in the erection of temporary buildings 
and can be quickly assembled or disassembled by unskilled help. 
Broadly stated, the present invention provides a joint for structural steel 
comprising: a first pair of parallel beams having a cross-sectional form 
with an L-shaped component; a second pair of parallel beams having a 
cross-sectional form with an L-shaped component; a U-shaped channel having 
two upstanding side walls and a bottom wall connecting the side walls, the 
bottom wall having one or more centrally located holes therethrough; said 
first and second pairs of parallel beams nesting within the U-shaped 
channel in end-to-end relationship without obstructing the holes of the 
bottom wall of the U-shaped channel; a clamping plate fitting into the 
U-shaped channel over the beams and having one or more holes aligning with 
said holes in the bottom wall of the U-shaped channel; and means for 
binding the clamping plate and the U-shaped channel together, said 
clamping plate forcing the said beams outwardly against the side walls of 
the U-shaped channel and downwardly against the bottom wall of the 
U-shaped channel.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The joint of the present invention is formed between two parallel pairs 1, 
2 of beams as shown in FIGS. 1 to 5. 
The beams 1, 2 nest within a U-shaped channel 3 having two upstanding side 
walls 4 and a bottom wall 5 connecting the side walls. The beams are of a 
cross-sectional form having an L-shaped component comprised of base 8 and 
wall 17 so that they can be seated against the inner surface of the 
U-shaped channel 3. In the preferred embodiment shown, the beams are 
S-shaped. 
The width 6 of the U-shaped channel 3 is greater than twice the base length 
7 of the beams so that the seating bases 8 of a parallel pair of beams are 
spaced apart when in place, as shown in FIG. 2. In this manner, holes 9 in 
the bottom wall 5 of the U-shaped channel are left unobstructed. 
A clamping plate 10, preferably having a width 11 slightly smaller than the 
difference between the inside width 6 of the channel and twice the 
thickness of the beams, is provided with holes 12 which match holes 9 in 
the U-shaped channel. This plate will be used to secure the beams within 
the channel. 
The joint is assembled as follows: a first pair of parallel beams 1a, 1b is 
seated inside the U-shaped channel 3. A second pair of parallel beams 2a, 
2b is brought in end-to-end relationship with the first set 1 of beams, as 
shown in FIG. 3. Holes 9 on the bottom wall 5 of the U-shaped channel 3 
remain uncovered. The clamping plate 10 is then placed inside the channel 
3 over the beams such that the holes 12 in the plate 10 align with holes 9 
in the U-shaped channel 3. Means, such as a nut 13 and bolt 14, are used 
to bind the clamping plate 10 and the U-shaped channel 3 together. The 
clamping plate then forces the beams outwardly against the side walls 4 of 
the channel and downwardly against the bottom wall 5 of the channel 
thereby securely holding the two pairs of parallel beams in end-to-end 
relationship. 
In an alternate embodiment, shown in FIG. 5, the bolts can be used to 
attach a vertical riser beam 15 and angled beam or joist 16. 
While the present invention has been disclosed in connection with the 
preferred embodiment thereof, it should be understood that there may be 
other embodiments which fall within the spirit and scope of the invention 
as defined by the following claims.