IMPROVEMENTS IN FLOATING BRIDGES
Year: 1881

page_text: LETTERS PATENT to Benjamin Pryor Stockman, of Number 3, Poet's Corner,
Westminster, in the County of Middlesex, Civil Engineer, for an Invention
of "IMPROVEMENTS IN FLOATING BRIDGES."
PROVISIONAL SPECIFICATION left by the said Benjamin Pryor Stockman
at the Office of the Commissioners of Patents on the 12th March 1881.
BENJAMIN PRYOR STOCKMAN, of Number 3, Poet's Corner, Westminster, in the
County of Middlesex, Civil Engineer. "IMPROVEMENTS IN FLOATING BRIDGES."
My Invention relates to floating bridges over rivers, estuaries, canals, or other
streams or pieces of water, which require to be opened from time to time to allow
of the passage of vessels or for other purposes, and consists in arranging the floating
bridge in two halves, each of which for convenience of description I call a half
bridge. Each half bridge is made to float by means of pontoons arranged as to
number and position in such manner as the exigencies of the case may require.
These "half bridges" are propelled from opposite shores of the river or other piece
of water, and meet in midstream or other suitable point, when they are required to
form a continuous bridge for the conveyance of traffic across the water from shore
to shore.
When it is required to open the bridge to allow vessels to pass, each "half bridge"
is propelled backwards sufficiently to leave the required opening between their
outer ends. The shore or back ends of the "half bridges" are contained in a kind
of dock or recess, which may be constructed of masonry, timber piling, or ironwork,
or any other suitable material, and in which each "half bridge" floats backwards
or forwards in order to open or close the bridge.
The approaches may be made double, that is to say, in plan, in the form of a
tuning fork, each prong of the fork forming a road or pathway leading on to the
single and central road over the "half bridge" the inner end of which lays between
the two said roads or pathways.
Where the river or other water is tidal each approach is placed on gudgeons or
hinges fixed at the shore end to piers or abutments, the outer end of each being
supported on a pontoon so that the approaches may rise and fall with the tide,
and thus coincide with the level of the "half bridge."

page_text: Where the river or other water to be crossed is narrow, such as a canal, for
example, and its whole width is required for navigation, the dock or recess in the
shore is made of sufficient length to receive the entire "half bridge." When
the river or other water is broad and the whole width is not required for
navigation, the dock or recess may be constructed wholly or in part beyond the i
shore and may take the form of projecting piers.
In some cases, and especially where there is no tidal current, a single approach
may be arranged, in which the "half bridge" runs on one side of such single
approach. The piers supporting the approaches or the sides of the docks or recesses
and the sides of the "half bridges" are provided with wearing or friction pieces or
rollers to steady and guide the said "half bridges" as they move in and out in the
dock or recess.
In large spans, and where there is a tide or current, the pontoons may be arranged
so as to leave water ways for the passage of the current, or of vessels that can lower
their masts, of barges, boats, and other small craft, but if the span is very small
and there is no tide or navigation the water ways may be dispensed with, and each
half bridge" supported on one pontoon only.
SE
The "half bridges" are propelled in and out of the dock or recess by propellers
operated by motive power carried on board the pontoons, or they may be hauled
in and out by endless bands or chains from the approaches; they may be constructed
of wrought-iron or steel, the superstructure being preferably of lattice or boiler
plate work, supported on pontoons as before described.
The Invention is applicable for any length of span, and any required number of
opening spaces may be arranged in the distance from shore to shore.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Benjamin Pryor Stockman in the Great Seal Patent Office on the
12th September 1881.
BENJAMIN PRYOR STOCKMAN, of Number 3, Poet's Corner, Westminster, in the
County of Middlesex, Civil Engineer. "IMPROVEMENTS IN FLOATING BRIDGES."
My Invention relates to floating bridges over rivers, estuaries, canals, or other
streams or pieces of water, which require to be opened from time to time to allow
of the passage of vessels or for other purposes, and consists in arranging the floating
bridge in two halves, each of which for convenience of description I call a "half
bridge." Each "half bridge" is made to float by means of pontoons arranged as
to number and position in such manner as the exigencies of the case may require.
Theso "half bridges" are propelled from opposite shores of the river or other piece
of water, and meet in midstream or other suitable point, when they are required
to form a continuous bridge for the conveyance of traffic across the water from
shore to shore. When it is required to open the bridge to allow vessels to pass,
each "half bridge" is propelled backwards sufficiently to leave the required opening
between their outer ends. The shore or back ends of the "half bridges" are con-
tained in a kind of dock or recess, which may be constructed of masonry, timber
piling, or ironwork, or any other suitable material, and in which each" half bridge
Hoats backwards or forwards in order to open or close the bridge.
"
The approaches may be made double, that is to say, in plan, in the form of a
tuning fork, each prong of the fork forming a road or pathway leading on to the
single and central road over the "half bridge," the inner end of which lays between
the two said roads or pathways.
Where the river or other water is tidal each approach is placed on gudgeons or
hinges fixed at the shore end to piers or abutments, the outer end of each being
supported on a pontoon, so that the approaches may rise and fall with the tide, and
thus coincide with the level of the "half bridge."
Where the river or other water to be crossed is narrow, such as a canal, for
example, and its whole width is required for navigation, the dock or recess in the
shore is made of sufficient length to receive the entire "half bridge." When the
river or other water is broad and the whole width is not required for navigation,
the dock or recess may be constructed wholly or in part beyond the shore, and
may take the form of projecting piers.
In some cases, and especially where there is no tidal current, a single approach
may be arranged in which the "half bridge" runs on one side of such singlo
approach. The piers supporting the approaches or the sides of the docks or recesses
and the sides of the "half bridges" are provided with wearing or friction pieces
or rollers to steady and guide the said "half bridges" as they move in and out in
the dock or recess.
In large spans, and where there is a tide or current, the pontoons may be
arranged so as to leave water ways for the passage of the current, or of vessels that
can lower their masts, of. barges, boats, and other small craft, but if the span is very
small and there is no tide or navigation, the water ways may be dispensed with,
and each "half bridge" supported on one pontoon only.
The "half bridges" are propelled in and out of the dock or recess by propellers
operated by motive power carried on board the pontoons, or they may be hauled in
and out by endless bands or chains from the approaches; they may be constructed
of wrought iron or steel, the superstructure being preferably of lattice or boiler
plate work supported on pontoons as before described.
The Invention is applicable for any length of span, and any required number of
opening spaces may be arranged in the distance from shore to shore.

page_text: In the Drawings hereto annexed, Figure 1 is an elevation of one example of a
floating bridge constructed in accordance with my Invention, showing the water
channel for masted vessels opened; Figure 2 is an elevation of the same bridge,
showing the water channel closed, but the roadway from shore to shore continuous
for the passage of vehicles and other road or railway traffic; Figure 3 is a plan of
the same.
a, a, are the approaches at each end of the bridge. Each approach has two
separate roadways, the spaces between them forming docks or recesses for the
reception of the "half bridges." Each approach roadway is composed of main
girders hinged at the abutment ends, and supported at the outer ends on pontoons,
so as to provide for the rising and falling of the tide; b, b, are the "half bridges,"
which are propelled in and out of their docks or recesses by any suitable means.
They are supported on pontoons to which they are rigidly attached, and by which
means they float like ferries. Under their superstructure and between the pontoons
there are water ways for the passage of the current, vessels that can lower their
masts or funnels, or of barges, boats, and other small craft as before described;
c, c, are the docks or recesses between the approach roadways; d, d, the waterways
under the roads of the "half bridges" and under the approaches; e, e, the pontoons;
ff, the abutments.
Assuming that the "half bridges" are withdrawn into their respective docks or
recesses, as shown in Figure 1, a free passage being open between their outer ends
for navigation, and that it is required to bridge the channel so as to provide a
passage from shore to shore for the road traffic, the means of propelling or hauling
the "half bridges" is put in action; and the "half bridges" float. longitudinally
outwards towards the centre of the channel, until their outer ends meet (their
hinder ends still remaining in their respective docks or recesses), when they form
a continuous roadway from shore to shore, as indicated by the arrows marked on
the plan, Figure 3. In this condition the bridge carries the road traffic, but when
it is required to reopen the mid-channel for navigation, the propelling or hauling
apparatus is again put into operation, and the two "half bridges" recede from each
other, until they arrive again in their respective docks or recesses, as in Figure 1.
The example of bridge above described and illustrated in the Drawings is
applicable to a tidal river, but it will be readily understood that the construction
and arrangements can be varied according to circumstances, and the nature of the
stream or piece of water it is intended to cross.
Having now described the nature of the said Invention, and the manner in
which the same is to or may be carried into effect, I would have it understood that
what I claim is,-
186
The combination of floating "half bridges" and approaches, so as to form at will
either a continuous roadway for the circulation or passage of road or railway traffic,
or an opening for the passage of vessels, by the floating and propelling of the said
"half bridges" to or from each other, such half bridges" being always more or
less in gear with or contained within their respective docks or recesses, and
connected with the approaches, as hereinbefore described and illustrated in the
Drawings hereto annexed.
In witness whereof, I, the said Benjamin Pryor Stockman, have hereunto