Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a structural member such as a
beam or joist for use in concrete forming structures for the
purpose of supporting poured concrete in walls, columns and slabs
employed in the building industry~ One such joist or beam forms
the subject of our Canadian Patent No. 941,123 which issued on
February 5th, 1975 and which includes a cold-rolled substantially
U-shaped channel or top chord which has elastically deformable
side walls capable of being sprung outwardly to admit a wooden
nailable insert into the channel;a lower chord spaced from the
top chord by primary and secondary chord connecting means; and a
pair of slotted nailer-plates each located at an opposite end of
the joist. This structural member, although admirable for its
purpose proved to be heavy and somewhat costly to manufacture.
A still further known type of beam or joist is
manufactured from extruded aluminum. This type of joist
also has a U-shaped channel or upper chord into which a wooden
joist member or insert is forced with the inner surfaces of said
channel being provided with serrations to inhibit movement of
the insert upwa`rdly in a vertical plane, and, hence, to separate
from the channel member. However, this type of structural member
suffered from the disadvantage that it was difficult to remove
damaged wooden inserts from the channel.
In consequence a further type of extruded aluminum joist
was evolved and this type forms the subject of our Canadian
Patent No. 1,045,34~ which issued on October 2nd, 1979 and which
included a U-shaped channel to contain a wooden insert with ~he
inner walls of the channel diverging away from one another towards
the bottom of the channel thus making it easier to remove said
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insert.
soth of the last mentioned structural members included
a slot in the lower chord to accommodate a bolt forming part of
a clamp adapted to clamp the joist to ano-ther supporting member.
Now it is well known to provide the free ends of the
upper and lower horizontal flanges of structural beams and
trusses with short stub ox strengthening flanges extending normal
to said horizontal flanges. However, due to their sharp edges,
these stub flanges have tended to become damaged with the rough
usage encountered on building sites, and moreover have not lent
themselves to easy connection of one joist to a supporting member
(short of employing the type of clamp just described) which
utilizes the slot and accommodated bolt.
Accordingly, it is the object of the invention to
provide a structural member having the type of inverted "top-hat"
section or U-shaped channel adapted detachably to receive lumber
inserts and to profile the free ends of the upper and lower
I flanges so that their stub flanges inhibit damage more than known
types while permitting relatively easy and quick connection to
other supporting members as required.
According to the present invention therefore, a
structural member is provided for the support o poured concrete,
said member consisting of an extruded, elongated channel member
;presenting an upper chord, a lower chord, and chord connecting
means intermediate said chords, said upper chord defining a
channel substantially U-shaped in cross-section adapted to permit
the introduction of a removable insert therein, said channel
having a pair of opposed side walls connected to a bottom wall,
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the free end of each said side wall terminating in an outwardly
extending flange normal thereto; said chord connecting means
comprising a central web extending between said upper and lower
chords; said lower chord being defined by a pair of flanges
parallel with, and spaced from, the first-mentioned flanges; the
free end of each said flange terminating in a stub flange profiled
by a pair of spaced surfaces, portions of which at least extend
substantially normal to the longitudinal axis of said web and
which terminate in a pair of converging surfaces so as to present
each said stub flange with a cross-section which is substantially
conical in cross-section.
The invention is illustrated, by way of example, in the
accompanying drawings in which:
Figure 1 is an end view of one type of structural
member showing the wooden insert in situ; and
Figure 2 to 4 are end views of alternative forms of
structural members.
Referring to the drawings, and in particular to Figure
1, the structural member shown therein (and which can be employed
as either a beam or joist) consists of an elongated channel member
presenting an upper chord, indicated generally at A, a lower
chord indicated generally at B and chord connecting means or web
(indicated generally at C) intermediate said chords A and B.
The upper chord defines a channel indicated generally
at D which is substantially U-shaped in cross-section and which
is formed by a pair of opposed side walls 1 connected by a
bottom wall 2. The upper end of each side wall terminates in an
outwardly extending flange ~ extending normal thereto.
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The lower chord B is defined by a pair o~ lower flanges
parallel with, but spaced from, the flanges 3.
The structural member includes a slot 5 of substantially
T-shaped cross-section located in the general area of the junction
of the web C and the lower chord B and which slot is adapted
slidably to receive a bolt-head 6 of a slidable clamp (not shown)
which does not fo.rm any part of this invention but which can,
in known manner, clamp a joist to another and adjacent structural
member.
The free end of each flange 3,4 terminates in a stub
flange profiled by a pair of spaced surfaces 7,8 portions of
which at least extend substantially normal to the longitudinal
axis of the web C and which surfaces terminate in a pair of
converging surfaces 9,10 so as to present each stub flange with
a substantially conical cross-section.
An insert 11 (which can be of wood) is forced into
channel D and detachably secured therein by any suitable means
such as nails. Plywood panels or dimensioned lumber are then
laid on the inserts and nailed thereto so as to support the
poured concrete.
In the form of invention shown in Figure 2, it will be
seen that the surfaces 7 of the stub flanges are much sharper
; than those shown in the arrangement of Figure 1. In other words,
they are much closer to extending at 90 to their associated
flanges 3 and 4. Other than that small difference, the second
alternative form of the invention is the same as that described
above and illustrated in Figure 1.
In the arrangement shown in Figure 3, the structural
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member omits the T-shaped slo-t 5 but the thlckness of the web C
increases, at 12, towards the lower chord B in the general area
of the junction of the web and said lower chord.
The arrangement shown in Figure 4 is similar to that
in Figure 3 except that the stub flanges are of the type shown
in Figure 2.
In all cases, the structural members are of extruded
aluminum and the angle between the converging surfaces 9 and 10 is
within the range of 80 to 100 and preferably 90.
From the above description, i-t will be appreciated that
the particular shape of the stub flanges are such that they will
resist damage caused by rough handling or abuse and permit the
fastening of two iden-tically flanged members to each other by
means of a suitable and complementary friction clamp such as
that described and claimed in copending Application Serial No.
368,630 filed January 15th, 1981- The said flanges also
provide gripping surfaces for positive connection and a ready
means for the self-centering action of the complementary friction
~clamp, as well as being completely visible for safety
inspections.
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