IM- PROVEMENTS IN THE CONSTRUCTION OF BEAMS OR SUPPORTS APPLICABLE TO THE BUILDING OF BRIDGES, VIADUCTS, ROOFS, ARCHES, AND SHIPS, AND IN INSTRUMENTS TO BE USED THEREIN
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by the said William Edward Kochs
at the Office of the Commissioners of Patents, with his Petition, on the
1st March 1865.
WILLIAM EDWARD KOCHS, of Cannon Row, in the City of Westminster
5 Civil Engineer, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN THE CONSTRUCTION OF BEAMS OR SUPPORTS APPLICABLE TO THE
BUILDING OF BRIDGES, VIADUCTS, ROOFS, ARCHES, AND SHIPS, AND IN INSTRUMENTS
TO BE USED THEREIN," to be as follows:-
This Invention relates to the employment of novel means for securing
0 strength and rigidity in wrought-iron and other beams, brackets, arches, and
other supports. The Invention may be said to consist in the use of rigid
skeleton triangles proportioned and disposed on a novel principle, which will
be clearly understood in its varied applications by reference to the accompany

page_text: &c.
ing Diagrams, which illustrate the adaptation of the Invention to the support
of the platforms of bridges, the construction of roofs, truss and other beams,
arches, and ship's hulls.
Suspended and Trussed Principal.-Figs. 1, 2, and 3 are representations
of the rigid triangle system applied in different manners.
The following is the
method of construction:-Let the horizontal or vertical line A, B, of a beam
be divided according to the load, say into equal parts; draw inclined lines
from these division points towards a point of a certain height or distance
above or from B, draw from each division point, Fig. 1 or 2, vertical, and in
Fig. 3, horizontal lines, and connect further each point of intersection with 1
the next one higher or below. If each of these systems of lines represent
rigid bodies adequate for carrying a certain load acting on every point in the
direction of the arrows, then the whole will be a rigid system and will fulfil all
requirements of a bracket or abutment.
Rigid Suspended Roadway.-Fig. 4 is a repetition of the same construc. 1
tion. Pairs of brackets of the previous description are connected back to back
at B, C, and B', C¹, and connections are made at the other ends as at A. The
whole will then form a continued roadway complete.
Rigid Trussed Roadway.-Fig. 5 is the repetition of the same construction
of trussed bracket of Fig. 2; two pairs of them are connected back to back
at B, C, and B, C, and at their ends at A, and thus form a continuous
roadway.
Rigid Cantilevers.-Fig. 6 is a repetition of the same construction; two
suspended brackets are connected back to back at B and C.
A. Suspended Roadway for Great Span on the Double Principle.-In
Fig. 7 the horizontal A, B, is divided into a double number of parts, and each
vertical line erected in the points of division stands in correspondence with
the next by the inclined and connecting lines as before; so the points A, D,
E, F, and G, and H, I, K, L, M, are corresponding points. Triangles A, D, N,
and D, E, P, are belonging to one, and H, I, O, and I, K, Q, to the other
system which intersect the one the other, and thus impart great strength
to the structure. Fig. 9 is a suspended road of large span designed on the
described principle.
B. Doubly Suspended Roadway for Great Span.-Figs. 8 and 10 are repre-
sentations of a double suspended system. A rigid principal such as Fig. 1 is
suspended on all intersecting points towards a point of suspension C', which is
placed a certain height vertically above a supporting point C. The system of
lines are constructed in the following manner :-Draw from the intersecting
point D of the triangle A, D, E, the inclined line D, C'; make D,G=D, F

page_text: and we have a rigid triangle D, G, F, by which through a connecting
line G, H, the weight is conducted towards the point of suspension C. In like
manner lines are drawn from all the points of intersection to the point C¹.
Fig. 10 is a full length illustration of a doubly suspended roadway for large
5 spans.
Suspended and Trussed Principal for Girders and Roofs.-Figs. 11 and 12,
draw the two right-angled triangles A, B, C, and A, B, D; let the two lines
A, B, fall together so that the right angles C, A, B, and D, B, A, be opposite
to each other. The lines C, B, and A, D, will intersect at point K, and form
0 three triangles C, K, A, D, K, B, and A, K, B, if the two triangles Fig. 11
be supported in A and B, then we receive the principle of a roof com-
posed of lines A, K, B, K, and A, B. Supposing the line A, B be a beam
requiring to be supported on three points, I draw from the two division
points E and F, lines towards C and D, and receive the intersecting points
5 G, H, I, L, and M, and the rigid system enclosed by A, G, K, I, B. In
introducing the lines G, H, and H, I, the system is divided into two, each
one rigid and independent from the other.
The Figure A, G, H, I, B, F, E, Fig. 11, represents a rigid beam on the
suspending principle, and the corresponding one in Fig. 12 on the trussed
principle.
Figs. 13 and 14 are repetitions of the same construction on a greater span,
and greater number of divisions. Fig. 13 is a girder on the suspended, and
Fig. 14 on the trussed principle.
Figs. 15 and 16 are rigid roofs designed on the suspended principle, and
in the same previous way.
Figs. 17 and 18 are girders inclined towards the centre or middle of the
bridge, both on the suspended principle.
Fig. 19 is a rigid gasholder roof designed on the trussed principle; there is
no centre or king post. From the centre of the top curve of roof I draw
lines C, D, and C, E, towards a point below the feet of roof A and B. Sup-
posing the line A, D, E, B, be ascertained, I draw D, F, and E, G, and again,
from points F and G, towards the points below, and so on. The true curve
of a gasholder roof is not a segmental, but an elliptical line, as shewn further
on in Fig. 25ª.
Rigid Arches.-Figs. 20 and 21 are inside trussed semicircular arches.
In Fig. 20 the equal loading is applied in parallel vertical directions, as the
arrows shew. The so caused unequal divisions increase towards the supports
A and B. From points vertically below A and B, supporting lines are drawn
towards these division points, and the triangles resulting from the intersecting

page_text: and connecting lines as before form the rigid trussed principle; Fig. 21 is
constructed in a similar manner, the load being applied equal all round, and
in the direction of the arrows on the points of division.
Fig. 21 is the outside of a trussed arch on the suspended principle. From
points a certain height above A and B the intersecting lines are drawn 5
towards the points of division, and thus the rigid principle is obtained.
The pointed arch, Fig. 22, is loaded and constructed on the same principle
as the round arch, Fig. 20, and the pointed arch, Fig. 23, as the round arch,
Fig. 21. The outside trussed arch, Fig. 23, is on the same principle as
Fig. 21.
The arches, Fig. 24, are designed in the same manner as the roof, Fig. 16,
on the suspended principle; the roadway is horizontally supported.
10
Figs. 25 and 25 are representations of a rigid trussed arch constructed in
the following manner :-From the points G and H vertically below the points
of support A and F I draw lines to the division or any points of the arch so 15
that the sum of two corresponding lines leading to G and H (for instance,
G, CC, H) is equal to the sum of two other corresponding lines, say
G, EE, H, or A, G + A, H. The curve A, F, will be found to be an
ellipse; it is constructed by laying a chord of the length A, G, H, A, on
points G and H, and describing with a pencil the curve from A to F. Fig. 25b 20
shews the application of the principle. The ellipse A, F, is trussed by a
triangular system constructed in the previous described manner.
Fig. 26 is an arch of great span with double or intersecting triangular
rigidity. The division points are in double number, so that each third corre-
sponds with the next. The construction of the system is as Fig. 24; this 25
arch and all can be built without rivets.
Fig. 27 shews a mode of erecting an arch from the piers. After the piers
have been brought up to the level of the road and the first triangular supports
of the arch A, E, F, F, E', at A and A', are fixed in their position, I arrange
a suspension point above pier and vertically above point A or A¹. The 30
triangles B, C, D, and B, C, D, are introduced and suspend point E and E¹
from C and C, further B, C, G, and B, C, G¹, and suspend the systems of
triangles H, I, E, F, and H', I', E, F, by the rods G, H, and G¹, H, and
so on. The whole forms a rigid system. The road of the bridge is laid
as they proceed with the erection. The suspending principal above pier will 85
be removed when the bridge is finished.
Hulls of Vessels.-The application of the Invention to the construction of
ships is shewn by the Diagrams, Figs. 28, 29, and 30. From the bottom or
keel along the outline or section line of a ship, begin, dividing equal or un-

page_text: js, &c.
equal distances, according to the pressure or depth of the ship to the level of
highest water line in A or B, then draw from the division points lines to a
certain point vertically above A and B. The triangles resulting from the
intersection lines connected as before, gives the rigid beam or keelsom A, B, C,
5 and A, B, C¹, of the vessel. These ribs are to be arranged in certain dis-
tances, whilst the intermediate keelsoms are only angle iron, to which and
to the bottom angle irons of the ribs the plates are firmly connected. No
plate girders for stiffening are required within the ship.
Fig. 30 shews my way of longitudinally trussing a ship. The beam repre-
10 sents the back bone of the ship, and is a repetition of a single or double
suspended beam shewn in Figs. 6 and 7. The pressure from the keel below
is conveyed by verticals meeting the centre of the cross ribs. Fig. 28 shews
also two side trussed beams constructed in the same manner as Fig. 1. The
mast is firmly fixed to the middle of the ship, and supported as well to the
5 longitudinal as cross beams.
In order to ascertain the direction of strains in any structures, and determine
the position of the point of support above referred to and exhibited in the
previous Figures, I use an instrument shewn at Fig. 31. Let A, C, represent
the span of a bridge or any other structure, the point B a point in the top
member loaded by any weight. The strain will follow the direction of lines
B, A, and B, C, and according to leverage will be greater towards A than
towards C. If the structure itself be of no weight, and have consequently no
thrust to the abutments, then an infinitely minute weight brought on point B
will go vertically down, and an increasing weight will gradually increase a
certain thrust towards A and C, and more in amount towards the point A than
towards C. The instrument consists of two separate triangular pieces A, B, F,
and B, E, C; the dotted lines B, A, and B, C, point towards abutments
A and C respectively; and the lines B, F, and B, E, are vertical; both
triangles are connected at B by a loose bolt to a vertical rod H, and they are
suspended vertically by cords at points A and C, so that these points are free
to move horizontally. Further, the weight of each triangle is counterbalanced
by weights G and G¹. The rod H slides in a fixed guide I. It will be seen
that as the instrument itself is balanced when a most minute weight W is
brought on to the point B, the vertical lines B, F, and B, E, will not move
laterally, but keep their vertical position; if however the weight le increased
the strain of it will gradually cause these lines to approach the points of
support A and C, and the line B, F, will incline in the direction of D, K,
whilst B, E, will incline in the direction of D, 1. The enclosed angles
D, K, E, and D, H, L, are the corresponding angles of strain. The lines

page_text: D, K, and D, L, will run towards the point of suspension or support; these
inclined lines and angles will naturally be altered by every other point of
load of the bridge, and will be equal only at the centre of the bridge as shewn
previous Figures.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed 5
by the said William Edward Kochs in the Great Seal Patent Office
on the 1st September 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD KOCHS, of 29, Charing Cross, in the City of Westminster, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of March, in the year of our Lord One
thousand eight hundred and sixty-five, in the twenty-eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said William Edward Kochs, Her special licence that I, the said William
Edward Kochs, my executors, administrators, and assigns, or such others as I,
the said William Edward Kochs, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF BEAMS OR SUPPORTS APPLICABLE TO THE
BUILDING OF BRIDGES, VIADUCTS, ROOFS, ARCHES, AND SHIPS, AND IN INSTRUMENTS TO
BE USED THEREIN," upon the condition (amongst others) that I, the said William
Edward Kochs, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said William Edward Kochs, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
This Invention relates to a novel mode of construction for securing strength
1

page_text: and rigidity in wrought iron and other beams, brackets, arches, and other
supports, particularly for the building of bridges of large spans.
The Invention may be said to consist in the use of skeleton triangles
proportioned and disposed on a novel principle, which will be clearly under-
5 stood in its varied applications by reference to the accompanying Diagrams,
0
which illustrate the adaptation of the Invention to the support of platforms
of bridges, the construction of roofs, truss and other beams, cranes, arches,
spires, lighthouses, and other like lofty structures, and to the longitudinal and
transverse trussing of floating vessels.
The advantages claimed for this Invention are, firstly, that wrought-iron
beams or principals for bridges and other structures can be brought together
in elementary bars or parts and fastened at their extremities by screw
bolts and nuts, in place of the usual rivets, and their rigidity and strength
secured.
5 Secondly, that bridges on the suspended and trussed principle and beams
constructed as herein-after described, are in their parts self-supporting, and
require for their erection far less scaffolding than when the system of structures
hitherto in use are applied, the beams themselves serving in their erection the
purpose of scaffolding.
Thirdly, by my novel disposition of material a bridge constructed on either
the suspended or trussed principle can be produced of larger span, and
structures in general can be erected on a larger practical scale, than hitherto,
the necessary strength and firmness being obtained with the use of a propor-
tionately less weight of material.
Section 1. Suspended and Trussed Principle, One Abutment.-The Figures
1 to 5, Plate I. are Diagrams illustrating the principle upon which all the
following applications to practical structures, as shewn on the same plate, are
based. The principle of my Invention in its simplest form consists in sus-
pending or trussing beams at or from several equi-distant points on the beam,
which trusses or supports all trend towards a certain point of suspension o
support, as the case may be.
Figures 1 and 2 shew a horizontal, Fig. 3 a vertical beam a, b, the one
suspended and the other trussed according to this Invention at several points
d, e, f, g, h, the tension rods and struts connected to the beams at those points
all converging to their respective points of support c, the converging rod
being for all practical purposes too long. The lines d, i, e, k, f, 1, represen
rods secured to the beam at right angles thereto in the points of divisio
d., e, &c. At the points of intersection which these lines make with the con
verging lines, rods i, k, k, l, l, m, &c. are introduced to connect the intersecte

page_text: points, and the strains caused by the weights or forces acting in the direction
of the arrows are thus transmitted in the shape of a curved or polygonal line
instead of converging lines towards the point c. Fig. 1 is a bracket on the
suspended, and 2, 3, and 5, on the trussed principle. In Fig. 4 a single
weight on point c is supported on several points of the wall or vertical 5
support a, b. The whole structure it will be seen consists of triangles which
may be composed either of single bars, and connected at their extremities by
bolts, as at Figures 7, 8, and 9, or may be cast in one piece, as at Fig. 6,
or brought together in several combined triangles, as at Fig. 10, each one
following the delineation of the skeleton principle. Each vertical or respectively
horizontal section constitutes a whole, and the bracket as shewn in Figures
7 and 8 can be considered complete at the line h, n, and at this section fixed
against the wall or support.
Figures 11 and 12 are representations of cranes constructed on the same
principle.
Fig. 13 is a similar arrangement of parts to that shewn at Fig. 12, but
forming in this instance the sides and roof of an iron house.
Fig. 14 shews the application of the abutment principle of Fig. 5 to the
construction of a church spire; the whole is built up in pieces and can be
completed by adding section to section.
Fig. 15 is a representation of an iron lighthouse, the rigid abutting principle
of Fig. 5 is introduced within the structure, as indicated by the dotted lines.
Each section in this instance may conveniently measure ten feet in height
and the width of the base being determined by the height of the structure
the points of convergence of the diagonal struts c (Fig. 5) will be readily
determined.
Fig. 16 is an illustration of the manner of supporting a high chimney shaft
by several vertical side brackets, such as at Fig. 5; the whole can be built
up in pieces, the outside trussing forming at the same time the necessary
scaffolding for its erection.
I. Single Principle. Suspended Roadway.-In Fig. 17 a pair of brackets
of the description of Fig. 1 are shewn as fixed back to back at the line b, c,
meeting thus at the centre line of the pier, their extremities being connected
as at a. The whole thus forms a continuous roadway complete. In Fig. 18
the lines h, n, of the brackets are brought together on the centre line cf the pier,
thus the two points of suspension, c and c', fall above and outside the pier at
the distance of one division.
Trussed Roadway.-Fig. 19 is the same bridge reversed; the bars previously
acting in tension are in this case brought to compression.

page_text: Swing or Lever Bridge.-Fig. 20 is a repetition of the same principle, two
suspended brackets being connected back to back at line h, n.
Fig. 21 is a combination of the two systems shewn at Figs. 18 and 19,
the trussed principle above and the suspended below being connected, and thus
5 forming a complete beam or girder.
II. Double and Treble Principle.-Figs. 22 and 24 shew the same sus-
pended principle as before, adapted for bridges of large span. The inclined
rods converging as previously towards one point are prolonged till they reach,
as in Fig. 22, the second, and in Fig. 24, the third vertical rod. By this
means a second and a third principal and new curved lines are obtained, by
which the strain is proportionately divided on more bars and thus transmitted
to various points of the pier. The acquired strength and stability of the
structure allows bridges to be executed of a larger span than hitherto. The
piers or supports, as shewn in these Figs. and in Fig. 23, are constructed
entirely on the same principle of bracket as shewn at Figs. 5 and 10.
The various parts of cast-iron framing are fixed together by bolts and nuts.
Fig. 25 is a full length bridge, constructed on the plan of Fig. 22, and
Fig. 26 of Fig. 24.
Fig. 27 is the bridge of the description of Fig. 25 reversed; it forms a
trussed or arched bridge for large spans.
Fig. 28 shews the principle applied horizontally for giving a lateral bracing.
By introducing it into the plan of these bridges the roadway is materially
stiffened. Fig. 29 is a combination of the suspended and trussed principle to
one bridge, the suspension being above and the trussing below.
Section II. Rigid Girders, Beams, and Arches, with Two Points of Support
or Two Abutments.-The Figs. 30 to 35, Plate II., are delineations of the
principle upon which all the following applications are based. It consists, as
before, in the suspending or trussing of a beam a, b, on several division points
d, e, in lines trending towards certain imaginary points of suspension or abut-
ment. In this case there are two such points, indicated at c and c¹, each being
a certain height or distance vertically above or below the two points of support
a and b. These converging lines intersect each other respectively, and by
introducing the horizontal f, h, a figure representing the outline of a rigid
trussed girder is produced. Figs. 30, 32, 33, 34, and 35 are on the suspended,
and Fig. 31 on the trussed principle. The points c, c', will rise and fall above
or towards the points of support a and b, according to the greater or less
quantity of load intended to be supported. The thickness of the beam, it
will be understood, must be adapted to the load it is to carry, as shewn at
Figs. 32 & 33.

page_text: Fig. 36 is a repetition of a system of Fig. 31; it represents a beam for the
support of floors.
Fig. 37 is the same as before doubly applied; it constitutes the longitudinal
bracing of a beam or shaft. Fig. 38 shews the practical application of the
same to the jib of a crane.
Figs. 39, 40, 43, and 44 are inside trussed arches; the load is applied, as
shewn by the arrows, either as in Figs. 39 and 43, in parallel, vertical, and
equal loads, or in right angles to the tangent of various points, as in Figs.
40 and 44.
Figs. 41 and 42 are outside trussed arches on the suspended principle.
Figs. 45 and 46 are representations of the principals of roofs; they are
constructed on the suspended principle; Fig. 47 is a gasholder roof on the
trussed principle; Fig. 48 is a combination of the inside trussed arch of
Fig. 44, with the vertical support of Fig. 5, Plate I.; the whole forms the
skeleton framing of a dome complete.
Fig. 49 is a horizontal beam of the description of Fig. 34. The double
division allows the beam of large span to be composed of comparatively shorter
bars or members.
Fig. 50 represents an arched bridge, on the suspended principle, designed
as Fig. 46. Fig. 51 is a similar trussed arch for larger spans ; the greater
number of divisions allows the arch to be composed of comparatively short
bars or members.
5
1
Fig. 52 shews how an arch can be erected above a precipice without
wooden scaffolding below. After the piers have been brought up to the level
of the road and the first triangular supports of the arch b, d, f, d, e, b, are fixed
in their position, there is virtually above the centre of the pier and rib of the
arch a suspension point, as arranged, from which triangles a, c, c¹², are suspended;
thus the foot of the arch is suspended by the rods c, d. Further, the triangles
a, g, c, and g, h, c, are introduced, and the additional triangles of arch d, i, f, and
f, k, i, are suspended by rods i, h, from the upper structure and so continued till
the centre is reached. Or rods next the pier can be furnished with right and
left-handed screws for the adjustment of the ribs of the arch. The platform of
the bridge is laid down whilst the erection is proceeding. The suspending
rods above the pier will be removed when the bridge is completed.
Fig. 53 shews the manner of laying out the curve for an arch; it is part o
an ellipse. The point cx c¹ or foci are vertically below the points of suppor
a and b, and in general c, a=a, b; the curve is drawn by laying a chord round
the points c and c' and by describing with a pencil the curve from a to b.
Beams for the Stiffening of Ships' Hulls and Longitudinal Bracing

page_text: Shallow Vessels.-Figs. 55, 56, 57, and 58 shew the application of the
Invention to the construction of longitudinal and transverse beams and ribs of
ships or vessels in general. Longitudinally, through the whole length of the
vessel, a beam composed of two cantilevers connected back to back at the
5 centre (in the line of the mast) is introduced. The same, thus combined with
the vessel, forms a strong back bone, and the beam having at the same time
the advantage of resisting equally well a compressive as tensile strain, will
afford internal strength against hogging and sagging, when the vessel is
supported either by one or two waves; the application of such beam is par-
O ticularly adapted for long and shallow vessels. The transverse rib, Fig. 56,
forms the partition in the centre of the vessel; it gives lateral support to the
central girders and masts. The ribs, Figs. 57 and 58, shew the bottom
and side trussing of the hull of the vessel against the under pressure of
water. The construction is on the same principle as Fig. 30 and following
5 Figures.
Fig. 59 shews the adaptation of the Invention to the strengthening of em-
bankments of rivers. Principals, constructed as shewn in the Diagram, are
worked into the ground at convenient distances, and act thus as resisting
anchors. Cast-iron pilings, with water-tight groves, are laid in in a sloping
direction, and thus form a sloping water-tight wall, behind which a stone
wall might be built up; a part of the cast-iron framings should be built into
the wall.
Apparatus for Illustrating theoretically the Comparative Direction of
Struts in Bridges or Beams.-Referring to Figs. 30 or 34, I desire to shew,
in order to demonstrate the correctness of the principle on which my Invention
is based, that if a point f on the top of a beam be loaded by a certain weight,
and the strut f, a, be inclined towards the point of support at an angle of 45°,
the corresponding strut f, d, should not as usual be set at an equal angle of 45°;
but at the angle a, d, f; further, that the prolonged line of d, f, will reach to
a point c of equal height above the point a as c¹ above the point b.
Fig. 60 represents the little instrument which I have contrived for demon-
strating the proper construction of truss beams. Let a, b, c, d, Fig. 60, be a
rectangular beam, and a, b, points of abutment, and e a point loaded with a
weight. In order to ascertain the action of the weight on the supporting struts
respectively, the dead weight of the structure is not taken into account, and
the struts are supposed to extend from a to b and from c to d in direct lines.
Supposing these struts to be levers moveable on a fulcrum at e, and to be
provided with bowles at their extremities a and b, so that they may freely mov
in a curved groove, the weight acting on each will force them into their require

page_text: position. Each lever has an indicator on its upper end, which indicates
a certain point situated vertically above the points a and b. If the weight
be removed, both the levers and their indicator will assume a vertical position.
If moved, they will proceed at equal horizontal distances a,f=h, i, and con-
sequently a, k=b, 1, equal a, b, that is, the struts are pointing to one point.
The struts on the other end of the abutment will naturally point to the same
spot; the struts in the centre incline at equal angles, and all others at
unequal angles, according to their position on the bridge.
The instrument shewn at Fig. 61, by which the direction of strains and
consequently the position for the struts in any structure may be determined, con-
sists of two segmental levers a, e, g, and e, h, b, which are suspended by vertical
cords at points a and b, representing the abutments to the girder or beam
a, b, c, d. These segment levers have their fulcrum ate and are counterbalanced
by weights w, w. The struts e, a and e, b, as in the previous Figure, are each in
their vertical position e, h and e, g. A graduated arc is suspended from the
point e, and over it pointers on the ends of the levers more under the pressure
of the weight on the fulcrum e and thus indicate the direction of the struts,
and the points k and l above as in the previous arrangement.
Having now set forth the nature of my Invention of improvements in the
construction of beams or supports, applicable to the building of bridges,
viaducts, roofs, arches, and ships, and in instruments to be used therein, I
wish it to be understood that I claim,-
First, constructing beams or supports of triangles built up or formed on the
principle above set forth, whereby the force of the tensile strain or of com-
pression will be transmitted to the abutments of such beams or supports.
And, secondly, the means above described for determining the direction for
the struts in beams and supports.
In witness whereof, I, the said William Edward Kochs, have hereunto
set my hand and seal, the Thirty-first day of August, in the year of
our Lord One thousand eight hundred and sixty-five.
Witness,
FRED. WALKDEN,
66, Chancery Lane.
W. E. KOCHS. (L.S.)