AN IMPROVED METHOD OF UNITING AND SECURING BEAMS OR PIECES OF WOOD OR METAL IN THE CONSTRUCTION OF BRIDGES AND FOR OTHER LIKE PURPOSES
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
12th February 1872.-A communication from abroad by Robert
A. MoLeod, of Florence, Italy.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "AN IMPROVED METHOD OF UNITING AND
SECURING BEAMS OR PIECES OF WOOD OR METAL IN THE CONSTRUCTION OF BRIDGES
AND FOR OTHER LIKE PURPOSES," a communication, to be as follows:-
The said Invention relates to constructing bridges, platforms, floors,
ceilings, roofs, domes, and other like structures without the aid of
pillars, columns, or similar supports, except at the extremities or borders
of the structure. For this purpose I employ beams of wood, iron,
or other metal or material, each of which is supported by resting at
or near each end upon another beam, and in its turn supports another
beam or number of beams resting upon it. The several beams which
meet together thus form and are sustained by self-supporting joints.
The said beams are fitted together by notches and tongues, whose
shape and dimensions are determined by the nature of the structure.

page_text: I carry my Invention into practice in the construction of a flat
bridge as follows:-The bridge is composed of two kinds of beams,
one of which has all its faces perpendicular to each other. It has
three notches one at each end exactly alike, and on the same side,
and one in the middle on the opposite side of the beam. I also use
another beam all of whose faces are perpendicular to each other, and
which contains four notches all of the same dimensions. The two outer
notches are on one side of this beam, and the two inner notches on
the opposite side. The length of the second beam is not necessarily
the same as that of the first beam. I place two rows of the first
mentioned beams with the central notch uppermost, and parallel to
them and between them I place two other rows with the central notches
opposite the end notches of the outer rows. Then with these beams I
combine the beams of the second kind, which are laid transversely upon
the first beams, the notches of all the beams being fitted together.
Each notch has a depth equal to one-half the depth of the beams,
therefore all of the upper surfaces of the beams thus fitted to each
other will lie in the same plane and form a flat structure. And if the
ends be supported, the whole will be supported and will form a firm
bridge.
In constructing a curved bridge the bridge is made in all respects
the same as that above described, except that the depth of the notches
is something less than one-half the thickness of the beams. The result
of this difference is that the bridge assumes a curved form. The exact
curvature depends on the depths of the notches, increasing as their depth
is diminished. This curved bridge is much stronger than the flat bridge
for two reasons: 1st, the notches being shallower the strength of the
material is not so much impaired; 2nd, the curved form gives it when
the ends of the longitudinal beams are made to fit closely all the
strength of the arch, while at the same time it has none of the thrust
of the latter.
In constructing a floor or ceiling I use a number of beams, all of
which are alike. All the faces of the said beams are perpendicular to
each other. There are four notches, two on one side which are alike,
and two on the opposite side also alike. In putting the beams together
to form a continuous floor the notches are so fitted together that the
beams form squares, and the ends of four beams lie together and form
therefore a self-supporting joint, and it is evident that if these ends be

page_text: supported the whole structure will be supported and make a solid floor.
Or I may make a floor or ceiling of a hexagonal pattern. This floor
is composed of beams all alike. The top, bottom, and sides of the
beams are perpendicular to each other, but the ends are inclined to
the sides at an angle of 60 degrees, that is, there are four notches, two
alike on one side, and two alike on the opposite side of the beam. In
putting these beams together to form a floor the beams are placed
together hexagonally, and the ends of three beams lie together. These
three ends thus form a self-supporting joint, and their upper surfaces lie
in the same plane, the structure being continued as far as desired. It
is evident that if the ends be supported the whole will be supported and
form a firm floor.
In constructing a dome I proceed nearly in the same manner as in
constructing a curved or arched bridge. A diminution of the depth of
the notches will convert the floor into a dome or roof curving in every
direction. Except in one or two special forms however the beams
should not be all of the same length.