Improvements in the Construction of Braced Metallic Girders.
Year: 1893

page_text: Date of Application, 14th Mar., 1893-Accepted, 2nd June, 1893
COMPLETE SPECIFICATION.
Improvements in the Construction of Braced Metallic Girders.
I, FRANTISEK PRASIL, of Prague, Bohemia, in the Austrian Empire, Civil
Engineer & Chief of the Bridgework of Prague, do hereby declare the nature of
my said invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The object of my invention is to effect improvements in the construction of iron
and steel girders for bridges, roofs, and analogous constructions.
In carrying out my invention I construct the panels or bays of the girder of one
uniform size, for the purpose of simplifying the construction: using the smallest
number of parts: economising labour and material, and facilitating transportation.
My invention chiefly consists in uniting the several parts of the girder by means
of internal right and left hand screws, whereby they are drawn together at one
operation for which purpose I use diagonal and other braces and stringers of
tubular form, where practicable; and, when using other sectional forms, the ends
are socketed and screw threaded, or formed with internal flanges or shoulders.
And in order that my said invention may be particularly described and ascer
tained, reference is hereby made to the accompanying drawings, in which similar
letters of reference indicate corresponding parts.
Figs. 1, 2 and 3, are diagrammatic illustrations, shewing the method of con-
struction, with diagonal braces, the horizontal connections a being made with
internal screws, and the cross connections being effected with bolts and nuts, as
shown in Fig. 8.
Figs. 4 and 7 illustrate methods of connecting tubes of equal section, by internal
right and left hand screws B' B². The ends 1 and 2 have corresponding internal
screw threads. The tubular screw B (Fig. 4) has polygonal conical ends for
receiving a key S, correspondingly formed, whereby the screw may be turned, and
the ends 1 and 2 of the tubes drawn together. Another method of turning the
screw is shewn in Fig. 7. The central portion of the screw is formed so as to fit
the polygonal plate C, by which the screw is turned until the ends of the tubes 1
and 2 press against the plate C on each side, as shown.
The
A method of uniting tubes of different diameters is shown in Fig. 5.
smaller pipe 1 has an internal screw thread, and the larger pipe 2 has a
shoulder x.
The screw B has a flange k; whereby the tubes are secured together,
as shown.
Fig. 6 illustrates another method of uniting tubes, or bars of any sectional
form; the ends being made tubular to form the junctions. The central portion of
the screw B is formed with teeth z, and when nearly screwed up, a suitable
tool is inserted in the opening o for drawing the ends 1 and 2 together, by turning
the screw.
Fig. 8 illustrates the method of connecting two triangular ends 3, 4, 3, 4, by
means of a tenon w, bolt 2 and nut 2¹.
Figs. 9, 10 and 11 illustrate cross braces and girder connections. The web of
a cross girder T may be connected with the tubular stretcher D, as shown in
Figs. 9 and 10. The web of the girder T is bored through to receive a screw B
(before described) to which the ends 1 and 2 are secured.
Referring to Fig. 11, the cross girder is supported by the tubular stretcher D
by means of the saddle T¹. The horizontal cross girder T is connected with the
vertical part by means of bolts passing through the tubular pieces m¹ n', and screwed
into the ends m n of the upper tubes. QQ are the heads of the bolts. Such
additional tubes as d are secured as before described.
Fig. 12 illustrates diagrammatically, the method of construction adopted in

page_text: bridges and viaducts. Starting from the pier r the several parts are added by
means of a travelling crane R, as shown; the crane following up the work. In
building from a central or other detached pier, the girders are extended on each
side simultaneously, so as to be in equilibrium.
Having now particularly described and ascertained the nature of my said inven
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In the construction of girders for the purposes aforesaid, the application and
use of tubular elements, or tubular ends to such elements, for the purpose of uniting
the same by means of internal right and left handed screws, substantially as herein
before described and illustrated by the drawings.
2. In the construction of girders as aforesaid, the application and use of a key S
for the purpose of turning the screw B, substantially as hereinbefore described
and illustrated by Fig. 4 of the drawings.
3. In the construction of girders as aforesaid, the combination of a right and
left handed screw B formed with teeth for turning the same by a suitable
tool, substantially as herein before described and illustrated by Fig. 6 of the
drawings.
4. In the construction of girders as aforesaid, the combination of a right and
left handed screw, the central portion of which is formed polygonal, and a plate C
correspondingly formed for turning the same, substantially as herein before
described and illustrated by Fig. 7 of the drawings.
5. In the construction of girders as aforesaid, the method of connecting the
tubular ends of different diameters, by means of a screw B, the head of which
engages an internal collar formed in the end 2, and the thread B' of the screw,
being secured to the end 1, substantially as herein before described and illustrated
by Fig. 5 of the drawings.
6. In the construction of girders as aforesaid, the method of connecting the
tubular elements with a cross girder T, substantially as herein before described and
illustrated by Figs. 9 and 10 of the drawings.
7. In the construction of girders as aforesaid, the combination of a saddle T
with the tubular element D, for supporting the several connections, substantially
as herein before described and illustrated by Fig. 11 of the drawings.
8. In the construction of girders as aforesaid, the method of connecting the
diagonal trusses 3, 4, 3, 4, by means of tenons, bolts, and nuts, substantially as
herein before described and illustrated by Fig. 8 of the drawings.
9. The general construction, combination and arrangement of the several and
respective parts, together forming my invention of improvements in the construction
of braced metallic girders, substantially as herein before described and illustrated
by the drawings.
Dated 11th March 1893
GEO.
DOWNING,
8, Quality Court, London, W.C., Agent.