IMPROVEMENTS IN BRIDGES
Year: 1884

page_text: I HENRY HARRIS LAKE of the firm of Haseltine Lake & Co Patent Agents
Southampton Buildings in the County of Middlesex do hereby declare the nature
of said invention for "IMPROVEMENTS IN BRIDGES" to be as follows:-
This invention relates to bridges for carrying roads or railways.
Arched beam bridges as heretofore constructed present the inconvenience of
being too flexible as when a load rests upon one of the extremities of such a bridge,
this extremity sinks, the other extremity being at the same time raised. Such
great flexibility presents, in certain cases, a defect which, according to this inven-
tion, I obviate by giving to the brigde the form of a trussed beam.
The characteristic feature of such a bridge is that it is formed of transverse pieces
having all the same shape and dimensions and joined together by means of similar
oblique and longitudinal pieces.
This bridge is rapidly erected, and when arranged as a horizontal trussed beam,
it may be thrown directly over a river or placed upon the piles or piers of a
metallic bridge which has been destroyed in warfare.
This bridge is formed of upper and lower cross bars arranged in two parallel
planes and joined together by means of braces of equal length, the said braces
forming regular parallelograms the lengths of the shortest diagonals of which are
equal to the sides thereof. These figures not being liable to lose their shape, the
skeleton beam of the bridge remains horizontal notwithstanding any unequal
distribution of loads thereon.
The said braces, some of which are horizontal whilst the others are oblique, have
all the same length and are terminated by iron pieces provided with perforations
through which are passed the said cross bars Upon the lower longitudinal braces
slide sockets which permit the insertion of intermediate cross bars connected
together by means of longitudinal and intermediate bars also passed through
sockets in such a manner that they serve as guides for the first mentioned cross
bars. This lower part of the structure serves as a support for the superstructure
which may carry a road,

page_text: In order to maintain the upper and lower longitudinal bars at a constant
distance from one another, rings are fixed upon the cross bars and held by set
screws, and outside the bars and upon the longitudinal beam are fitted metallic
caps also secured by means of set screws. When, instead of the cross bars, iron
tubes are used, cylindrical rods provided with rings and having screw-threaded
pins and nuts may be inserted into the extremities of the said tubes.
These rods and nuts, and likewise the set-screws, serve to hold the extremities
of iron braces which prevent the bridge from moving laterally.
The same result could be obtained by means of two supplementary cross bars
pushed or forced as far as possible, and held in position by means of wedges or of
rings provided with set screws.
The bridge thus formed may be arranged with either side uppermost; in one
case the extremities of the upper cross bars may be joined with the lower longi-
tudinal bars by means of ropes stretched by means of couplings provided with
Bcrew threaded hooks; in the other case, ropes are unnecessary.
I may use in the construction of these trusses ordinary materials such as rails,
T-iron bars, and the like. Any kind of material, either wood, iron or the like will
answer the purpose.
This bridge presents the advantage of requiring only a small quantity of material
for its construction whilst offering a great resistance and perfect rigidity.
The horizontal or oblique bars can be boxed in at their extremities and are
_articulated together in the same manner as the two pieces of a hinge joint,
which reduces by half the thickness of the sides of the skeleton-beam-of-the-
bridge.
A bridge constructed according to my invention may rest upon an arch formed
by trussed ties crossing each other and provided at their extremities with circular
perforations and circular cross bars.
This arrangement however whilst requiring a large quantity of material has the
disadvantage of being too flexible, as above stated.

page_text: COMPLETE SPECIFICATION.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of my invention for "IMPROVEMENTS IN BRIDGES " and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
This invention relates to bridges, and has for its object to so combine a number
of pieces of the same form and dimension, that they can be united with one another
in order to form a rigid framing.
The framing offers great facility of mounting, dismounting and transport, and
can be adapted to spans of variable dimensions.
The invention is illustrated in the accompanying drawing the figures of which
are hereinafter referred to.
The improved framing is composed, of two series of cross-bars A and a, figures
1, 2, 3, placed parallel to and at equal distances from one another, longitudinal
bars c and d maintaining the distance between the bars of each series.
These two series of bars which are in different horizontal planes are held in
their respective positions at the desired distance apart by diagonal bars or braces b
of equal dimensions, arranged as shown in Figure 1, the two bars b connected to
each extremity of each upper cross-bar a being connected to the extremities of two
lower cross-bars A, and vice versa.
The bars thus arranged constitute a rigid skeleton applicable to the construction
of bridges.
The principal elements of this structure are the longitudinal or diagonal bars
figures 5 and 6, and the intermediate or cross bars, figures 7 and 8. Figure 11
represents the upper cross-bars.
These parts can be made of iron, steel, or wood, and of different sections, but
uniform and of the same length for each element of the same structure,
In the bridge which is represented in figures 1, 2, 3 of the accompanying
drawing, the upper and lower cross bars a a a A A A arranged in two horizontal
planes one above the other, may have either a cylindrical, rectangular or any other
suitable section, the ends upon which are secured the ends or eyes of the bars bod
being cylindrical.
The bars b c d which may also be of cylindrical, rectangular or any other suitable
section and of the same length, possess, at their extremities, eyes adapted to receive
the cylindrical ends of the cross-bars A a, and connect these latter horizontally
as well as vertically, forming by means of intermediate bars regular parallelograms
the short diagonals of which are equal in length to the sides.
This form of framing is inflexible and maintains a horizontal position even when
a load is unequally distributed.
The longitudinal, diagonal bars, and the cross-bars, are held in place by nuts g,
Figures 12 and 18, on the screwed ends of the cross bars, shoulders also being
formed, if necessary, on the cylindrical parts of the cross-bars,

page_text: The superstructure for a railway, or other road can be arranged either upon the
lower cross-bars A or upon the upper cross-bars a, according to the position of the
framing relatively to the level of the way, by means of longitudinal beams f,
figures 9 and 10, connected to the aforesaid cross-bars.
The horizontal and diagonal bars connected at their extremities, as shown in
figures 12 and 13, are articulated to each other like the two parts of a hinge,
in which manner the thickness of the side parts of the skeleton of the bridge is
reduced by one-half. It is to be understood that the said bars can be joined in any
other manner providing they are always articulated at their junction. The whole
framing is strengthened by horizontal braces h and vertical braceą j arranged
chiefly at the two extremities.
The right-hand portions of figures 1, 2, and 4 represent a double skeleton
consisting of one framing placed within the other, thereby increasing the strength
of the structure.
I can use for this kind of structure, railway rails or T-iron.
In the case where the form of the cross-bars used is cylindrical and of uniform
diameter, an arched bridge can be constructed with the same elements as shown in
figures 14 and 15, in which the cross-bars are designated by A. and the longitudinal-
bars by B.
Figures 16 and 17, 18 and 19, 20 and 21, represent the ends of the longitudinal
bars and their connection with the cross-bars, use being made of double T-iron,
wooden beams or hollow iron bars.
Having now particularly described and ascertained-the-nature-of-my-said
invention, and in what manner the same is to be performed I declare that what
I claim is
First. The system of framing herein before described which can be dismounted
and extended at will, and is formed of two principal elements viz the cross-bars,
and the longitudinal and diagonal bars having uniform dimensions, joined together
like hinges and so connected or jointed as to form a rigid structure presenting a
rectangular section, of which the top and bottom are formed of cross-bars and
longitudinal bars, and the vertical parallel sides of diagonal bars.
Second. The application of the same elements to the construction of arched
bridges.
HASELTINE, LAKE & Co.,
For the Applicant.