Improvements in the Construction and Working of Suspension, Revolving, or Rotation Bridges.
Year: 1890

page_text: Date of Application, 9th Aug., 1890-Accepted, 25th Apr., 1891
1317137
Improvements in the Construction and Working of Suspension,
Revolving, or Rotation Bridges.
1. PEDRO MARIA DE MERLADET, of Bilbao, Bizcaya, Spain, 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 invention relates to improvements in the construction and working of
suspension, revolving, or rotation bridges, the improvements and novelties embodied
therein may be summarized as follows:-
:—
The bridges according to my invention may be revolving, suspension, or fixed
and may be of one, two three or more divisions or sections of equal or different
lengths and breadth as preferred or as required by the special situation or conditions
of locality navigable channel, pass, docks, wharf, quay etc. for which they are
required. Those of one division or section are very economical in erection and
maintenance and also for the working where opening and closing is required.
When one of these bridges is to be located on a higher level than that of the
ground or quay or ordinary tide, or where the ordinary tide or swell of the sea or
river makes a variable height of platform a sloping jetty up to the required level
can be constructed.
And in order that my invention may be the better understood I now proceed to
describe the same in relation to the drawings hereunto annexed reference being had
to the letters and figures marked thereon. Like letters refer to like parts throughout
the drawings.
Figure shows a one section bridge Pacross the channel or river.
Figure 2 shows a two section bridge closed.
Figures 3 & 4 show a one section and a two section bridge connected up
together.
Figure 5 shows a two section bridge open allowing the passage of vessels.
Figures 6 & 6 show the camber or arched curve permissible in the construction
of the road-way, when desired in a one and two section bridge respectively.
Figure 7 shows details of false pier lifters and cable guide.
Figure 8 shows details of movable carrying horses or chevalets set in the bed of
the river.
Fig. 9 is a broken detail of the tower or pier & the rotating cable shaft & bridge
bracket driven by gearing & steam power.
Bridges of two or more divisions or sections with a diagonal joint at the middle,
or other position required for greater facility for opening and closing either way
may be built from 150 to 200 metres or more from abutment to abutment and those
of one division or section can be more than 100 metres in length (proportion of height,
dead weight, motive power etc. being taken into consideration), and from 2 to
4 metres in width, which also may be greater ;-due technical proportions being
always observed.
The thickness and height of the main piers shall be in proportion to the length
and the width thereof. The number of these piers shall be two in a two section
bridge, and one in a one section bridge, the foundations to be in proportion to the
height, weight and pressure upon the said piers or pillars, which may be of
quadrilateral, hexagonal, or octagonal form, and they shall be provided with sharts
& gearing capable of supporting and giving motion to landing stages by means of
one or two engines as the case may be, the base being of the requisite width for the
installations thereon.

page_text: These piers or pillars may be of triangular or rectangular diamond shapes and
may be of open lattice work with uprights ties and stays etc. Where it is thought
experient the main road-way may have a curve or camber with a rise of from one
to 5% of the span at the centre or ends of the section or sections of the bridge, as
shown in Figs. VI and VI without departing however from the diagonal joint G
where the ends meet.
An under support or bracket is provided in one of the sections in a two section
bridge. This bracket is also needed when the bridge is located on a level, but in a
one section bridge the support or bracket is unnecessary as the suspended end rests
on the ground.
The main road-way shall have strong sides, more or less wide and thick from the
starting point, the whole being made as simple as possible within the limits of
necessary strength, in order that the working parts may have the least possible
strain thereon. The same will hold good respecting the suspension cables which
may be 4, 6, 8 or more in number according to the length of the section of the
bridge, and their thickness to be in proportion to requirements, 6 to 10 strands, and
7 to 9 wires in each strand, steel wire rope being preferred, bound at every metre
length, and covered, for better preservation and resistance to the deteriorating
action of the weather."
These cables may clasp one another or cross at their highest point either as they
are or by means of other cables so that the resistance to a moving load may be
more uniform.
The said cables are passed through eyes or over brackets A on a vertical
column H. Fig. 9 capable of being revolved to the right or left according as the
bridge may be open or closed, by motion from the engine situated on the ground or
lower floor of the pier.
The engine may be hydraulic, electric, steam, or any other motive power, and all
the cables, upper and lower, whether for support or for turning, shall pass over
rollers or cushions A allowing the cables to run smoothly without chafing permitting
the free motion of the suspension cables when the column or shaft H. supporting the
upper or other cables turns in any direction.
These cables are made fast about mid-height of the piers or lower down or at the
foundations to iron drums M Fig. 9 protected against the weather, and are capable
of being tightened or slackened independently of each other according to the amount
of strain required.
The pillar brackets and cable guides A. Figs. 7 & 9 with projecting and revolving
arms are fixed on the shaft in the pier at a suitable height to carry the cables and
moorings to drums as stated above, and can be inspected daily at conveniently
situated man holes.
These cables after being secured to the sides of the bridge may if thought
necessary be passed in one piece under the road-way for greater strength and
security. Besides the main cables, so as to reduce the strain upon them when a
two section bridge is worked false piers, struts, or supports, of suitable thickness
and height may be fixed at lengths of 7, 10, 15, or 20 metres or other required
distance apart underneath the sides of the sections, up to the top of the railing,
perpendicularly, or with sufficient slant to better sustain weight and hinder vibration
as shown at B on the drawings.
The seat or base of these struts or legs may be round, square, triangular, bracket
form, fork, tripod, reversed T or any other form, as shall adapt them in the best
manner for the particular nature of the bed of the river, or channel upon which
they resi.
These false piers or struts may be in pairs or disposed alternately on both sides
starting from the junction ends, or close thereto in the two section bridge, (in
the one section bridge they are entirely unnecessary,) and they can be hoisted or
lowered by means of hand mechanism similar to that used for brakes as shown on
the drawings at D Fig. 7 or by a hand wheel E; they may also be operated by

page_text: means of a common horizontal shafting S, situated on each side under each section
of the bridge, with suitable gearing, (the motion for which is obtained from the
engine,) actuating small toothed wheels upon the struts or legs so as to raise or
lower them, as desired, when the bridge is to be opened or closed.
When the bridge revolves towards a quay the obstruction of the struts is
obviated, by those towards the land turning upon the interior of the landing stage
by means of a groove or circular wheel worked by a handle thus avoiding concussion
by their folding tightly against the walls and allowing the landing stage on
nearing the quay to rest on little iron steps N projecting from the quay
needful buffers may be located upon the said steps to prevent concussion or
injury.
If
In the case of bridges without a resting quay or those located by the con-
struction of ramparts or stairs on a higher level than the quay a column with
a bracket may afford a support for the landing stage or sections of the bridge
at the requisite elevation.
The junctions of sections of bridge one with another and of the landing stage
with the quay shall be of the radius required to permit of the rotation of the
sections and a couple of toothed wheels Q Fig. 9, similar, or different, superposed
upon one another, which shall receive from the engine the rotating motion on
either side towards the centre or from centre to sides: thus the junction G may be
diagonal in the two section bridge, square, round or otherwise, in a one section
bridge, and the junction with the land or shore may be the most adaptable to the
level of the ground.
Two revolving brackets T Fig. 1. fixed to the wall shall embrace the sides of the
single section bridge and fold against the quay, similar to the seat of the sections at
a convenient height & width.
A moveable swinging grating fixed from the shore shall prevent the rotation of
the bridge when in use, at the same time affording protection to passengers, animals.
and vehicles in transit. Horizontal or lateral bahistrades shall secure the junction
of the sections and the railing may be supported or secured by similar balustrades
The entrance arch 1. and the main body of the pier shall be in proportion to the
width of the road-way which may be from 24 to 4 or 5 metres or more, so also shall
the base, thickness of frame, and the strength of the foundations J (of dressed
stone or concrete) be in due proportion to the length and breadth thereof. The
ingress and egress ends of the bridges may be wider than the rest of the passage
with duc allowance for the swinging rotation of the bridge.
The erection of one of my bridges from commencement to termination takes
about three months, only without the employment of any scaffolding or other
obstruction to navigation.
The engine K or other power machinery shall be of the size required by the
locality and the power proportionate to the weight and dimensions of the road ways,
gear, shafting, piers, besides that actually required.
The heights and weight of the piers are in due proportion to the gravity, length,
movement, and weight of the road ways.
These latter are in proportion to the weight and speed of the traffic. By
employing suspension cables, double way bridges may be erected, the one for the
passage of railway trains, the other for tramway, cart, animal and passenger
traffic.
For greater security (this is also applicable to a single way bridge), these double
way bridges shall be provided with struts situated at an acute angle towards the
stream or current of the river, in pairs and coupled underneath the landing stage,
forming a carrying-horse or chevalet, four of them to a section, to be put in the
form of small piles or piers resting on the bottom of the river and coupled or
connected to the upper arms for hoisting or lowering the ordinary struts or false
piers.
The space between the under surfaces of the landing stage or road-way and the

page_text: stays crossing and embracing the carrying horses or chevalets shall be from two to
four feet, the said chevalets may have single or double connections.
Although not of absolute necessity in order to obtain the rotation of the landing
stage with greater facility, a cable may be run on each side horizontally from the
end of the stages or road-ways to the quays and may be fixed to a crab or winch S; 5
this of course will require additional power either manual or from the engine,
these cables being tightened or slackened whenever the bridge is open
closed.
or
In order to increase the rigidity of the top of the piers (although not absolutely
In like 1
required) tension cables from the same may be moored to the shore.
manner when necessary piers may be placed on each side near the centre or other
convenient position, in one section bridges which may be hoisted or lowered by hand
power by a windlass or pulley-blocks.
This method is very economical and allows the hoisting or lowering to be effected
instantaneously.
The engine may be located in the main body of the piers on the right or left on
the ground floor in the passage way or in any other convenient position. The other
space above and below in the piers can be used as store rooms for tools, offices,
dwellings for enginemen, or employés etc. etc.
The interior of the piers shall be in communication throughout by means of
stairs. The top F of the cable support H shall be protected by an ornamental
Heuron or light roof which may not obstruct the swinging motion of the two arms
and cables.
Each part of the piers shall be securely trussed and braced to adjoining parts,
and all bolts and rivets shall truely fit the holes in members with a view to better
support the structure during the shock and strain of the cables when at work, and
during the suspending and rotating of the railed and floored landing stages
or road ways which as already remarked should be as simple and light as possible
within the limits of absolute or relative security to passengers and all other sort of
traffic, or when a train or railway traffic is to cross.
In a one section bridge, used for mixed traffic, all other kinds of traffic but
railway is suspended during the crossing of a train.
:
To open or close one of these suspension and rotation bridges, 5 to 10 minutes is
required for two section bridges, and half that time for a one section bridge. To
open the bridge, that is to connect for passage, the two sections, each of which is
secured on the respective sides of the river or canal, (as shown at Figure 5) and to
start the engine which is always in readiness only three minutes are required to
connect the two ends and give the rotative motion that causes the struts or legs
to descend, of whatever form they may be, or by what power worked, and to close
the bridge or shut off the passage, the railing is removed in one minute, and the
embracing links unhooked; in two minutes the struts or legs are hoisted, and in
three minutes at the outside the two sections swing from the centre of the canal or
river to rest on the quay.
As only an accessory, a small gate, closing outwards, may be placed at the arch
of the pier when the bridge is closed, although the double railing of the landing
stage cuts off the passage, but should there be any opening between this and the
pier a small chain can form the fence.
From the front of the quay towards the canal and middle of the pier and landing
stage small revolving buttresses R of suitable length and thickness may be run out
starting from the centre, and attached to a small vertical column abutting on the
quay and swinging in either direction in order to support the landing stage.
The sections of this bridge can swing up or down the river as most convenient
for the passage of vessels, which passage is never obstructed or injured as the
engines and employés are always ready when required.
In addition to the arrangements above proposed, the sections and landing stages
may be swung round off and on to fixed or moveable carrying horses or chevalets

page_text: provided with grooved circular bearings at each extremity, made firm in the bed of
the river and of any form preferred such as shown at V. Fig. 8.
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 :-
The construction and working of suspension, fixed, or revolving bridges of one or
more sections by the special arrangement of piers, cables, pulleys, landing stages,
buttresses and other combinations substantially as and for the purposes described
and illustrated in the drawings hereto annexed.
Dated this 9th day of August 1890.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.