C A communicationc.
Year: 1898

page_text: Date of Application, 6th Dec., 1898-Accepted, 18th Mar., 1899
Improv C
A communication by THE MASCHINENBAU ACTIEN GESELLSCHAFT NÜRNBERG, of
24, Kessler Strasse, Nürnberg, in the Empire of Germany, Manufacturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of
Warwick, and 322, High Holborn, in the County of Middlesex, 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:
In large cable bridges the suspension cables were mostly made on the spot of
separate wires or strands. Apart from the fact that this work required a very
great deal of time, the action of the weather had to be taken into calculation
during the construction whereby the exactness of the work is unfavourably
affected. Efforts have therefore been made for some time to form the cables for
large bridges of separate small cables or pieces of cable, each of which is separately
portable.
Such an arrangement is shown in the accompanying drawings in which:-
Figure 1 is a cross section of a cable composed of a number of small cables k
which, usually parallel to and suitably grouped as closely as possible round a
larger cable K, are combined to form a single strong cable and bound together
with suitable sockets or straps. Of course in this arrangement vacant spaces r
remain between the separate cables which may be filled up by pouring into them
a suitable material but which must always he regarded as a drawback. Another
drawback consists in that the attachment sockets or loops which effect the suspen-
sion of the bridge-way on the combined cables only come in contact with the
cable at single points of its periphery, so that the absolutely necessary resistance
against displacement of the loops in consequence of the difference in the tension
of the strands before and behind said loops can only be obtained with difficulty by
means of friction alone. By the use of cable loops as recently proposed a large
amount of dead weight is caused. In order to avoid the drawbacks arising from
the combination of several ropes or cables lying in close proximity parallel with
or twisted round one another to form a single strong cable and to avoid the increase
of weight which is involved by the use of the said cable loops, by the present
invention a suitable number of the weaker ropes are arranged and anchored
independently of one another, and only subsequently connected or combined in
some suitable manner. The improved method consists in suitably suspending the
separate ropes and connecting or combining them by special devices in such a
For this purpose
way that they act reliably as a single suspension device.
Leach of the ropes is provided at both ends with an anchor head and fixed by
means of anchor supports independently of the others in such a way that its
adjustment un to a clearly determined tension may be effected. The ropes are
supported over the pyramids of the centre piers by means of suitably rounded
saddles.

page_text: As regards the present improved construction of a bridge formed on this general
plan, the essential parts of the same show the following peculiarities of construc-
tion.
Figure 2 is a vertical cross section of 4 cables combined in a group.
Figure 3 a vertical cross section of 5 rows each of 4 superimposed cables and
their mode of attachment.
Figure 4 a side view of same;
Figure 5 a lateral diagram, and
Figure 6 an end view of a saddle support
Figure 7 shows an elevation of a bridge constructed according to this arrange-
ment, whilst
Figure 8 is a vertical cross section and
a
b C
:
d
e
Figure 9 a side view of the rows of cables arranged at different heights.
In the arrangement shown in Figures 3, 4, 5 and 6 five vertical rows
are employed, each consisting of 4 cables i lying one above the other which with
a view to their manifold suspension are carried over the piers by saddles f
g h
and and anchored at the ends. These cables, as shown in Figures 3 and 4 are
so interconnected and held at a certain distance apart that the suspension rods H,
which have to carry the bridge-way, distribute the strains which arise, evenly over
all 20 cables in such a way as to yield an entirely central strain but no side ones.
In order to attain this, the 4 ropes of each vertical row are combined in one group.
Their respective distance apart is fixed, as shown in Figure 2, by means of
suitably shaped iron and steel blocks 2 with a loop 3 of flat iron passed round
the whole, leaving at first a gap at 2. After a closing piece 4 has been inserted
in said gap, all four cables i are so pressed under high pressure between the upper
bend of the flat iron and the closing piece 4, that when the closing piece has been
secured by means of screws or in any other suitable manner, the blocks 2 and
loop 3 cannot slip along the cables 1.
The cables are pressed into the loop of fiat iron by means of hydraulic power or
screw presses, using a lever mechanism of any suitable kind. As shown in
Figures 3 and 4 any suitable number of groups of cables put together in the
manner just described, or at different heights as shown in Figure S (hereinafter
described), may be placed at the suspension place for the bridge-way and in the
first named form of construction (Figures 2, 3 and 4) connected together by
bolts 5 intended for the suspension by means of bands 6. For this object the two
arms of each flat iron loop are strengthened or thickened in the centre and
provided with suitable bolt holes for the bolts 5. In the form of construction
shown in Figures 8 and 9 the separate groups of cables are arranged at different
heights and instead of a single bolt 5, five are employed whilst the number of
cables remains the same, each group of cables being separately connected with the
bridge way by separate suspension rods attached to the bolts 5. by means of
bands 6.
The suspension of the bridgeway obtained in the manner hereinbefore described
is an absolutely reliable one because the clamping in of each separate cable or
rope of a group always takes place with equal exactitude and care, so that in
the present case for instance the frictional resistance to slipping down of the
bridge suspension will be 20 fold the amount of that which is to be expected with
a single strong cable of the same weight-carrying capacity and under the most
favourable conditions.
The transfer of the strain from the suspension rods H. to the cables or ropes
takes place by means of the bands 6 by the intermediary of the bolts 5 so that
each separate group of ropes a b c d e bears the same load in their central plane,
consequently the strain on each cable or rope is equally great and central.
The constraction of the pyramid supports for the central piers where the here-
inbefore described grouping of the cables or ropes is employed, is evident from
Figures 5 and 6.
The lowest row of cables rests on a curved saddle 2, which saddle is in turn

page_text: carried by a sliding mount P. This row of cables is covered by a second saddle h
with spaces for play of the cables to allow of their being drawn through when
required to be changed, and this second saddle h has grooves on its convex side for
the second row of cables. Two further saddles and complete the pyramid
support. In order to cause the separate saddles in their total expansion to rest
with their curved surfaces in contact at l m and n they are slotted radially at certain
places Z and obtain thereby a certain flexibility.
The construction hereinbefore described has also the advantage that each
separate rope or cable may be separately changed without the necessity of
staying or supporting the bridge, it being only necessary to remove one vertical
row in which the cable 'to be replaced is included, by unfastening the fastening
bolts 5. During the period that one vertical row of cables is removed, care must
be taken to suitably reduce the load on the bridge. The openings in the saddles
over the piers for supporting the cables, are, as already incidentally mentioned,
somewhat larger than the thickness of the cables in order that the cables may be
easily drawn through the same when being changed.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondents, I declare that what I claim is:-
1. A suspension bridge characterized by the supporting cables being formed of
a number of independently anchored cables supported by curved pyramid sup-
ports, on which cables the suspension rods of the bridge way are pivotally attached
by means of a special suspension device gripping each separate cable or rope, in
such a way that the load for each cable is entirely central, that is to say acts
in the direction of the central axis and is equally distributed, substantially as
hereinbefore set forth.
2. A suspension device for suspension bridges such as described, characterized
by a usually even number of weaker cables () lying in a vertical plane one above
the other being held together under strong pressure in a group by means of
intermediate pieces (2) and a loop (3) placed round the whole and being combined
with several similarly formed groups of cables lying in proximity to one another
by means of single cross bolts (5, Figure 3) or several separate ones (Figure 8),
to form a suspender or suspension cable on which by means of said bolts (5) the
suspension rods H may be centrally suspended, substantially as herein before
described.
3. A pyramid support for suspension bridges such as described, characterized
by the separate rows of cables or ropes lying in proximity to one another being
supported by suitable saddles (f g h i¹) provided with grooves and formed to the
curve of the cables, which saddles are arranged one upon the other and brought
into mutual inner contact by means of radial slits (=) and as a whole may be
mounted rigidly or slidingly, substantially as hereinbefore described.
Daied this 5th day of December 1808