A NEW OR IMPROVED INSTRUMENT FOR SETTING OUT CURVES be as follows:-
Year: 1885

page_text: I, WILLIAM HENRY BECK of 115 Cannon Street in the City of London
Consulting Engineer and Patent Agent do hereby declare the nature of the said
invention for "A NEW OR IMPROVED INSTRUMENT FOR SETTING OUT CURVES
be as follows:-
"
to
Tables for setting out the connecting curves of alignments give the value of the
ordinates to the chord or to the tangent but these ordinates are only shown for
certain points, so that if intermediate points are required, which often happens,
very laborious calculations have to be made which entail a very considerable loss
of time and which are prejudicial to the progress of the operations in the field.
In setting out a railway for example all time lost by a surveyor in making
calculations in the field causes a corresponding loss of time to all the assistants and
workmen associated.
The object of the instrument forming the subject of the present invention is to
obviate this loss of time. It furnishes the means of finding, without any
calculation whatever, the value of the ordinates of any point of the curve. It also
replaces the theodolite with advantage, as it enables all the operations heretofore
effected by that instrument to be performed, as easily as, and with greater rapidity
than by it.
The use of the new or improved instrument has therefore the advantage, over
tables, that it gives with great exactitude and by simple inspection the abscissa
and ordinate of any required point in the curve. There is therefore no loss of time
as the operations can go on without stoppage and with great facility because the
apparatus is much more convenient to handle than tables.
The instrument consists of two parts, firstly, of a telescope theodolite, and
secondly, of what the inventors term a "Campylograph" adapted to the theodolite
for the purpose of giving all the elements necessary for setting out a curve, any
two elements of which are known.
The theodolite, which serves to measure the angles of the alignments, is of the
ordinary kind with a telescope. One semi-circle of the circular plate a of this

page_text: theodolite (see the diagrammatic Drawing hereto annexed) carries at a¹ divisions
corresponding to the degrees of the circle, and concentrically a series of semi-circles
divided into equal parts to serve for reading the total developement of the traced
curve as hereafter explained. Concentrically with the plate a is placed a graduated
bar OA furnished with verniers for reading the circumferential divisions of the
plate a. Beyond the pivot the bar O A receives and guides two other bars F G
and CD both perpendicular to and sliding on OA; they may be brought together
until F G is superposed over CD so that the longitudinal grooves with which they
are provided exactly correspond with each other.
The bar C D is intended to form a support to a limb b, from the centre of which
radiates a straight edge c, jointed to a vernier scale, which is mounted concentrically
with the limb b.
The bar CD rests by the common centre of the limb b and of the vernier scale,
in the groove of a bar fixed and braced to the foot of the instrument.
The bar CD has a longitudinal groove formed in it for the adjustment of the
limb b in any required position on the said bar; this adjustment is effected by a
pinion on the limb b gearing with the teeth of a rack along the outside edge of the
bar C D.
The straight edge c is connected with the bar F G by sliders, one of which is
fixed to the straight edge c at a definite point H given by the radius of the curve
to be traced, and the other slides on F G.
The instrument is furnished with a spirit level and levelling screws.
The theoretical and practical demonstration of the instrument is as follows:-
When the angle of two alignments, such as A. O and OI for example, (see the
diagram) is known, there are fixed either the radius of the curve, the tangents to
the curve, or the bissectrix according to the nature of the ground. If the radius is
fixed, the tangents and bissectrix are deduced from it. If the tangents are fixed,
the radius and the bissectrix are deduced therefrom, and if the bissectrix is fixed
the radius and tangents are deduced therefrom.
The bar O A is graduated so that its zero is at the point O round which it
pivots, and on this bar move the bars C D and FG which are perpendicular
to O A, and have the zero points of their graduations at C and F respectively.
The straight edge c has its end D sliding on CD, while its edge always passes
through the point O.
OA represents one of the alignments, C D the radius of the curve, and O D the
bissectrix of the angle of the alignments, the further action of the apparatus is
evident.
The angle D is known, and is equal to half the supplement of the angle AOI of
the alignments equal to half the angle x.
Examples 1. To find the bissectrix and the tangent, the angle and the radius
being given.
The bissectrix O D is moved along the bar C D until the distance CD is equal
to the radius measured on the scale into which the bar C D is divided, then the
radius CD is moved on the tangent A. O in one direction or the other till the angle
at D is equal to half the angle x, it then only remains to read the lengths OC
and DO on their respective scales.
2-If instead of the radius the bissectrix is given, C D is moved on OA till the
angle at D is equal to balf the angle x, and CD and D O are read off on their
respective scales.
The operation is similar when the angle and the bissectrix are given, the tangent
and the bissectrix, the radius and the bissectrix, or the radius and the tangent, and
Bo forth.
Setting out the curve-The curve being thus completely and exactly determined
it only remains to set it out by abscissæ and ordinates. For this purpose the
bar FG serves as a slide for the slider fixed to the straight edge c at H, the
straight edge c being for this purpose moved round the centre D into the positions
illustrated by dotted lines radiating from the said centre D.

page_text: For setting out the curve the bar CD is fixed in place on O A, the point D is
fixed on CD, and the straight edge c is fixed to the upper slider at H at a
distance H D from the centre D equal to the radius, the lower slider (to which the
upper one is pivotted) moving in the groove in F G.
The sliders of the bar F G and the straight edge c allow the bar F G to be
moved on A O, so that the nearer F G approaches the point C the more the
distance F H diminishes, and the further F G is removed from C the more the
distance F H increases.
In all positions the distance F H represents the ordinate and the distance CF
the abscissa.
The end of the straight edge c is furnished with a sight which serves to give the
direction of the middle point of the curve.
Partial developements of the curve.-The developements of distances between
pickets in a curve are given by the limb from the centre b and for a radius of one
hundred mètres, which allows of having corresponding abscissæ and ordinates for
points equally or unequally distant.
Total developement of the curve.-The plate a of the theodolite gives, to a
smaller scale, the total developements of the curves traced, by reading one or other
of the verniers on the bar A O.

page_text: i
COMPLETE SPECIFICATION.
"
A New or Improved Instrument for Setting Out Curves.
"
I, WILLIAM HENRY BECK of 115 Cannon Street in the City of London,
Consulting Engineer and Patent Agent do hereby declare the nature of the said
invention for "A NEW OR IMPROVED INSTRUMENT FOR SETTING OUT CURVES'
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
accompanying sheet of drawings and to the letters and figures marked thereon
that is to say :-
Tables for setting out the connecting curves of alignements give the value of
the ordinates to the chord or to the tangent but these ordinates are only shown
for certain points, so that if intermediate points are required, which often happens,
very laborious calculations have to be made, which entail a very considerable
loss of time, and which are prejudicial to the progress of the operations in the
field.
In setting out a railway for example, all time lost by a surveyor in making
calculations in the field causes a corresponding loss of time to all the assistants
and workmen associated with him.
It also
The object of the instrument forming the subject of the present invention is to
obviate this loss of time. It furnishes the means of finding, without any
calculation whatever, the value of the ordinates of any point of the curve.
replaces the theodolite with advantage as it enables all the operations heretofore
effected by that instrument to be performed as easily as and with greater rapidity
than by it.
The use of the new or improved instrument has therefore the advantage over
tables, that it gives with great exactitude and by simple inspection the abscissa
and ordinate of any required point in the curve. There is therefore no loss of
time as the operations can go on without stoppage and with great facility because
the apparatus is much more convenient to handle in the field ti an tables.
In the drawings hereto annexed Figure 1 represents a plan of the instrument
and Figure 2 an elevation.
The instrument consists of two parts, firstly, of a telescope theodolite, and
secondly, of what the inventor terms a Campylograph" adapted to the theodolite
for the purpose of giving, when the angle of the two alignements is known, all the
elements necessary for setting out the connecting curve.
The theodolite, which serves to measure the angles of the alignements, is of the
ordinary kind with a telescope, the circle a of which, carries at a divisions
corresponding to the degrees of the circle, and concentrically, a series of semi
circles, divided into equal parts, to serve for reading the total developement of the
traced curve as hereafter explained. Concentrically with the plate a, is placed a
graduated bar OA furnished with verniers at A¹ A1 and A2 A2 for reading the
circumferential divisions of the plate a. One of the vernier arms A', for example,
is for reading off the even divisions, and the other vernier arm A³ for reading off
the odd divisions. Beyond the pivot, the bar O A receives and guides two other

page_text: bars F G and CD both perpendicular to, and sliding on, O A. The bar C D slides
simultaneously on one side B B' of a right angled piece O, B, B₁ forming a rigid
piece with the bar O A, and its verniers A¹ A². The bars F G and C D may be
brought together until F G is superposed over C D so that the longitudinal
grooves, with which they are provided, exactly correspond with each other.
The bar CD is intended to form a support to a limb b from the centre of which
radiates a straight edge.c jointed at c to a vernier scale c² which is mounted
concentrically with the limb b.
The bar CD rests by the common centre of the limb b and. of the vernier
scale c² in the groove of a bar d fixed and braced to the foot g of the instrument
by a strut f from the same support g. This bar CD has a longitudinal groove h
formed in it for the movement of the limb b; this movement is effected by a
pinion on the limb b gearing with the teeth of a rack along the outside edge of
the bar C D.
The straight edge c is connected with the bar F G by two sliders m and n
respectively, one of which m, is fixed to the straight edge c at a definite point H
(see Figure 3) given by the radius of the curve to be traced and the other
slider n is fixed to F G.
All the parts composing the campylograph are divided with the greatest
accuracy in the manner clearly shown in the plan Figure 1.
The instrument is furnished "with a spirit level N, Figure 2, and levelling
screws.
The theoretical and practical demonstration of the instrument is as follows:-
When the angle of two alignements is known, there are fixed, according to the
nature of the ground, either the radius of the curve from which the tangents and
the bissectrix are deduced; the tangents from which the radius and the bissectrix
are deduced; or the bissectrix from which the radius and the tangents are
deduced.
The apparatus represents the above elements on a small scale and enables them
to be transferred to the ground for tracing the curve by points of which it gives
the positions.
The bar OA (see Figure 3) is graduated so that its zero is at the point O, round
which it pivots, and on this bar move the bars CD and FG which are
perpendicular to OA and have the zero points of their graduations at C and F
respectively. The straight edge c which is seen at DO has its end D sliding
on CD; while its edge always passes through the point O, which results from the
combination of the limb b and vernier c³.
OA represents one of the alignements, CD the radius of the curve, and OD
the bissectrix of the angle of the alignements; the further action of the apparatus
is evident. The angle D is known, and is equal to half the supplement of the
angle of the alignements equal to half the angle x.
Examples. 1. To find the bissectrix and the tangent, the radius R being given.
The bissectrix O D is moved along the bar CD by the rack and pinion until
the distance CD is equal to the radius measured on the scale into which the
bar C D is divided; then the radius CD is moved on the tangent A O in one
direction or the other till the angle at D is equal to half the angle x; it then only
remains to read the lengths O C and D O on their respective scales.
2. If instead of the radius, the bissectrix is given, CD is moved on OA till the
angle at D is equal to half the angle x, and Č D and D O are read off on their
respective scales.
The operation is similar when the angle and the bissectrix are given, the tangent
and the bissectrix, the radius and the bissectrix, or the radius and the tangent, and
so forth.
Setting out the curve-The curve being thus completely and exactly determined,
it only remains to set it out by abscissæ and ordinates. For this purpose, the
bar F G serves as a slide for the slider n when the bar OD (or c in Figures 1
and 2) is moved.

page_text: For setting out the curve, the bar C D is fixed in place on OA, the point D is
fixed on C D, and the two sliders m n are connected. In order to belong to the
curve, the point H must always be at a distance HD from the centre D equal to
the radius.
The sliders m and n of the bar F G and the straight edge c (F G and D O in
the sketch, Figure 3) allow the bar F G to be moved automatically on A O so that
the nearer F G approaches the point C, the more the distance F H diminishes,
and the further F G is removed from C, the more the distance F H increases.
.
In all positions the distance F H represents the ordinate and the distance C F
the abscissa.
The end of the straight edge c is furnished with a sight x which enables the
angles to be measured by the limb b.
Partial developement of the curve.-The developements of the distances between
pickets in a curve are given by the limb b and for a radius of one hundred mètres,
which enables the corresponding abscissæ and ordinates to be obtained for points
equally or unequally distant from a curve.
Total developement of the curve.-The plate a of the theodolite gives, to a
smaller scale, the total developements of the curves traced, by reading one or other
of the verniers A¹ A² on the bar A O.
The details of construction, and the forms, materials and dimensions of the parts,
may be varied according to circumstances without departing from the nature of
the invention.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is
The new or improved instrument for setting out curves arranged and adapted
for use with a theodolite; such instrument consisting of a combination of graduated
bars which represent and measure, to a reduced scale, all the elements of the curve
to be traced on the ground; and partially or wholly the developement of the said
curve, as hereinbefore described and illustrated in the drawings hereto annexed.
Dated this ninth day of Ontahan 100%