Improvements in Movable Bridges.
Year: 1894

page_text: Date of Application, 5th Dec., 1894
Complete Specification Left, 3rd Sept., 1895-Accepted, 5th Oct., 195
PROVISIONAL SPECIFICATION.
Improvements in Movable Bridges.
THOMAS WALTER BARBER of Ellora, Silverhill, St. Leonards-on-Sea in the
County of Sussex, Engineer, do hereby declare the nature of this invention to be
as follows:-
My improvements relate to bridges having movable or opening spans, and are
designed to simplify their construction and working.
For these purposes, instead of the usual swinging spans, moving horizontally on
vertical pivots; or of the "bascule" type swinging vertically on horizontal pivots;
I construct the movable span so as to telescope or slide within the fixed spans or
abutments; for which purpose I make them narrower than the fixed portion and
cause them to travel on wheels or rollers running on fixed rails attached to the
fixed portion.
The opening span may be in one or two parts. In either case the platform of
the movable span is suspended or supported upon swinging arms so as to rise and
fall far enough to pass under or over the platform of the fixed span; and I balance
the movable platform by weights or hydraulic pressure, adjusted by leverage so as
to give a correct balance in all positions. The movable span may be operated by
hydraulic or other power as in other movable bridges.
The floor or platform may be applied to either the top or bottom flanges of the
main girders, and is made as shallow in thickness as possible. In the former case
it falls and passes under the fixed platform in opening, and in the latter case it rises
and passes above the fixed platform.
Dated this 5th day of December 1894.
THOMAS WALTER BARBER.
Improvements in Movable Bridges.
THOMAS WALTER BARBER of No. 165 Queen Victoria Street London E.C.
Civil Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
My improvements relate to bridges having movable or opening spans and are
designed to simplify their construction and working. For these purposes, instead
of the usual swinging spans, swinging horizontally on vertical pivots, or vertically
on horizontal pivots, I construct the movable span so as to telescope or slide within
the fixed span or abutment in the manner shown in the drawing in which Fig. 1 is
a cross section and Fig. 2 is a longitudinal section of such a bridge or of one half
of such a bridge partly opened with the platform above the main girder & Fig. 3 is
a cross section & Fig. 4 a longitudinal section of such a bridge or hall bridge partly
opened with the platform fixed to the lower members of the main girders, 1. 1. are
the fixed main girders or abutments, 2. 2. the travelling girders, 3 the fixed platform
& 4 the movable do. The latter is supported by hinged arms 5. 5. journaled in the
travelling gidere, 6 is a link connecting all the arms 5 to the levers 7. 7. which
1 Drinn 877

page_text: carry the balance weight 8, which is heavy enough to balance the movable
platform 4 in all positions. The travelling girders 2. 2. run on wheels 9. 9. upon
rails 10. 10. attached to the fixed girders or abutments.
It will be seen that the movable platform has a rising & falling motion which is
given to it by two guide rollers 11. 11. attached to its inner corners & which travel
in curved channels or guides 12 as the travelling girders are moved in or out, which
may be done by hand winches connected to the travelling wheels or by fixed
winches with a rope or chain or by hydraulic cylinders with multiplying gear &
ropes in the ordinary way.
Instead of the balance weights 8 I sometimes employ a hydraulic double acting
cylinder to raise and lower the movable platform.
Having now particularly described and ascertained the nature of my said inven-
tion 1 declare that what I claim is :-
1st. The construction of opening bridges having the movable platform supported
on swinging links pivoted in the movable girders so as to rise & fall far enough to
pass above or below the platform of the fixed portion, in conjunction with guide
rollers, curved channel guides, and a balance weight & levers as shown and
described, the whole movable gear travelling to & fro on rollers & fixed rails.
2nd. The application of a hydraulic double acting cylinder & piston to raise and
lower the movable platform instead of a balance weight.
Dated this 14th day of August. 1895
T. W. BARBER.