Year: 1888

page_text: Date of Application, 14th July, 1888
Complete Specification Left, 13th Apr., 1889
Complete Specification Accepted, 8th June, 1889
I, JOSEF HEIDLER, of Gmunden Austria, Engineer of Forests, do hereby declare
the nature of this invention to be as follows:-
This invention has for object improvements in measuring instruments based on the
geometrical properties of two rods of equal length connected or pivotted to each other
at their middle. If there be drawn a rectangle of which the four corners coincido
with the four ends of these rods, it will be seen that opposite sides of the rectangle
are in all possible positions of the rods respectively equal, and that two adjacent sides
are always proportional to each other as the sine and cosine of one and the same
angle. Therefore if the opposite pairs of the ends of the rods be connected by
means of two straight rods or bars in such manner that one of the two rod ends
situated on one bar, shall be capable of rotation on its pivot and the other not only
capable of rotation but also capable of being shifted relatively to the bar then it will be
seen that the two rods can move relatively to each other through angles of Fig. 0° to 180°.
During this movement the bars remain constantly parallel to one another, and the
distance of the two parallel bars can always be found from the distance of the rods
ends measured along a bar. The preceding combination of parts is thus suitable for
use as a measuring clamp.
If the similar ends of the two rods be connected in the manner described with a
rod, viz. the one end only capable of rotation on a pivot the other both capable of
rotation and of translation an instrument is formed similar to a pair of callipers, by
means of which the dimensions of hollow spaces can be readily measured.
The said combination of co acting parts may also be used to measure horizontal
and vertical angles, in which case sighting devices are arranged.
In one form of instrument particularly applicable as outside callipers, two rods are
connected at the middle of their length by a pivot which is fixed to one of the rods
and bears at its free end a thumb nut. One set of ends of the rods are connected by
pivots with the one set of ends of a pair of straight bars whilst the other ends of the
rods are connected by means of pivots with small sliding pieces capable of moving
along guides fixed to the aforesaid bars.

page_text: +
In this manner the two bars are each, held in two points which are relatively
speaking far from each other, which ensures their exact parallel position.
A scale formed on one of the two bars in conjunction with an index on
sliding pieces indicates the distance between the bars.
one
of the
In constructing this instrument, the scale can be readily computated according to
the Pythagorean Theorem but it can also be empirically determined with the aid of
an accurate rule.
It is not necessary that both sliding pieces should be next to each other when the
instrument is closed. They may be arranged at the ends of one and the same rod,
although in that case the instrument would have a form less convenient in handling.
Instead of placing the scale for reading off the measured dimensions, upon one of
the bars, a scale may be fixed at right angles upon one of these bars the other bar
will then be moved parallel to itself along this scale.
In a modification designed for measuring cross dimensions of hollow spaces, the
rods are pivotted together at their centres, and are connected together at one end, by
means of an arc, which is fixed to one rod, and is moveably connected to the other
rod. On this are is indicated not the angle but the length of the corresponding
chord.
When an instrument according to this invention, such as that first described is
applied to measuring vertical angles, the person using the instrument grasps each of
the two bars, with one hand, and takes a sight along one rod (which is provided with
suitable sighting devices) towards the apex of the angle; at the same time he is able
to watch a spirit level which is situated on the lower bar.
When the rod carrying the sighting devices has been brought into the direction of
the line of vision towards the apex of the angle which is to be measured, the distance
of the sliding piece from the rear end of the instrument indicates the cosine of the
angle. The scale of the instrument may show the angle itself, or any other desired
function of the angle.
When the instrument is applied to measuring horizontal or inclined angles, the
distance between the bars constitutes one of the given dimensions of a right angled
triangle, and the angle (measured as hereinafter described) constitutes the second
dimension, so that the distance of the apex of the triangle can be readily determined.
In this case the system of rods and bars is connected by means of a universal joint
with a standard, and after one of the bars projecting from the standard, has been
directed towards the apex of the angle, and the distance between the bars has been
adjusted, a sight is taken from the junction of one of the rods and bars towards the
apex of the angle; the angle to be measured can be read off from a graduated arc
attached to one of the bars.
As the side of the triangle corresponding to the distance between the bars is very
small in proportion to the other sides, and the angle at the apex is in consequence
very sharp, telescopes must be arranged on the bars which will enable an exact
measurement of the angle to be taken.
Dated this 14th day of July 1888.
W. LLOYD WISE,
Per J. F. Brougham.

page_text: COMPLETE SPECIFICATION.
Improvements in Measuring Instruments.
I, JOSEF HEIDLER, of Gmunden in the province of Upper Austria, Austrian
Empire, Engineer of Forests, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
The improvements in measuring instruments, which form the object of this invention,
are based on the geometrical properties of two straight rods of equal length, pivotted
to each other at their middle. If there be drawn a rectangle, of which the four
corners coincide with the four ends of these rods, it will be seen that opposite sides of
the rectangle are in all possible positions of the rods respectively equal, and that two
adjacent sides are always proportional to each other as the sine and cosine of one
and the same angle.
Therefore if the opposite pairs of the ends of the rods be connected by means of
two straight rods or bars in such a manner that one of the rod ends connected to one
and the same bar shall be capable of rotation only round the point of connection, and
the other not only capable of rotation but also capable of being shifted along the bar,
it will be seen that the two rols can move, relatively to each other, through angles of
from 0° to 180°. During this movement, the bars remain constantly parallel to one
another, and the distance of the two parallel bars can always be found from the
distance of the rod ends measured along a bar. The preceding combination of parts
is thus suitable for use as outside callipers.
If the two pivotally connected rods be combined with one bar only, in such a
manner that one rod is capable of rotation on a pivot, the other both capable of
rotation and of translation, an instrument is formed similar to a pair of callipers, by
means of which the dimensions of hollow spaces can be readily measured.
The said combination of co-acting parts may also be used to measure horizontal
and vertical angles, in which case sighting devices are arranged.
The annexed sheet of drawings illustrate the mode of carrying into practice the
several applications of the combination of rods and bars herein before described :--
Fig. is an elevation of outside callipers according to this invention, in a closed
state.
Fig. 2. shows a cross-section on line x x Fig. 1.
Fig. 3 shows a cross-section of the opened instrument, on a line passing above the
shiftable pivots, perpendicularly to the bars.
Fig. 4 is a cross section of one of the bars, on a line situated in proximity to the
fixed pivot.
Fig. 5. is an elevation of the opened outside callipers as used for measuring the
diameter of the trunk of a tree.
Fig. 6 is a diagram of a modified form of the instrument designed for measuring
cross dimensions of hollow spaces, and shown as used for measuring the inner
diameter of a hollow cylinder.
Figs. 7 & 8 show diagrammatically the employment of the instrument for ineasuring.
vertical and horizontal angles.

page_text: In the form of the inst: ument, illustrated by Figs. 1 to 5, the two rods a a are
connected at the middle of their length by a pivot & which is fixed to one of the rods,
and carries, at its free end, a thumb nut c. One pair of ends of the rods a a are
connected at d d by pivots with the one pair of ends of two straight bars ee whilst
the other ends of the rods a a are connected by means of pivots ff with small
sliding pieces capable of moving along metal guide bars hh secured to the
aforesaid wooden bars e e.
In this manner, the two bars e e are held at equal distances from each other in two
lines, which are relatively speaking far from each other, which ensures their more
exact parallel position than is the case in other known outside callipers; consequently
my improved callipers ensure or render possible more exact measuring. The scale
formed on one of the two bars e e indicates at the point, where the sliding piece g is
situated for the time being, the distance between the bars e e corresponding to this
position of the sliding piece. In constructing this instrument, the lengths to be
protracted on either of the bars e e can be readily computed according to the
Pythagorean theorem, but they can also be empirically determined with the aid of an
accurate rule. el el are grooves or notches, intended to receive the thumbs of the
operator.
As already stated it is not necessary that both sliding pieces should be next to
each other when the instrument is closed. They may be arranged at the ends of one
and the same rod a although in this case the instrument would have a form less
convenient in handling.
Instead of placing the scale for reading off the measured dimensions, upon one
of the barse a scale may be fixed at right angles upon either of these bars; the other
bar e will then be moved parallel to itself along the said scale.
In the modification of the instrument shown by Fig. 6 and designed for measuring
cross dimensions of hollow spaces the two rods a a pivotted together at have
but one pair of ends connected to a bar, and in order to dispense with hinge-jointing.
the said bar is not a straight one but an arc i to which one of the rods a is rigidly
connected at whilst the other rod a has its end k adapted to move along the
arc i. On this are is indicated not the angle but the length of the corresponding
chord.
When the combination of jointed rods and bars, which forms the subject of this
invention, is to be used as an instrument for measuring vertical angles, as illustrated
by Fig. 7 it is the parallel position of the bars e e which is utilized for the purpose in
view. The person using the instrument grasps each of the two bars e e with one
hand, and takes a sight along one of the rods a (which is provided with suitable
sighting devices) towards the apex of the angle a to be measured; at the same
time he is able to watch a spirit level m which is situated on the lower one of the
bars e.
When the rod a carrying the sighting devices has been brought into the
direction of the line of vision towards the apex of the angle a which is to be
measured, the distance of the sliding piece g from the rear end of the instrument is
a measure of the cosine of the angle a. The scale of the instrument may show
the angle itself or any desired function of the angle.
Fig. 8 shows an instrument according to my invention for measuring horizontal or
inclined angles for the purpose of inferring from such an angle the distance of its
apex. The distance between the bars e e which can be very exactly set, constitutes
one of the known quantities of a right angled triangle, and the angle measured in
the manner hereinafter described constitutes the second known quantity, so that the
distance of the apex of the angle can be readily computed. In this case, the
system a a ee is connected at d¹ by means of a universal joint, with a stand, and
after the bar e projecting from the stand has been directed toward the apex n of the
angle, and the distance d¹² properly adjusted, a sight is taken from toward the
apex of the angle, and the angle ẞ which is equal to the angle ẞ is read off upon
the graduated arc o. As the side d' d² of the triangle is very small in proportion to
the other sides, and the angle at is in consequence very sharp, telescopes must be
arranged at d¹ and d which will enable an exact measuring of the angle ẞ.

page_text: Having now particularly described and ascertained the nature of the said inven-
ion and in what manner the same is to be performed I declare that what l
claim is :-
1. In callipers and angle measuring instruments, two rods a a of equal length
pivotted together at their middles, the ends of these rods being connected by pairs to
two straight bars e e in such a manner that in either pair one end is pivotted to the
corresponding bar, and the other end pivotted to a sliding piece movable along the
said bar, this arrangement being such as to keep the bars e e in exactly parallel
positions at whatsoever distance apart they may be placed by changes in the relative
positions of the rods a a.
2. In outside callipers, comprising rods such as a a and bars such as ee a scale
situated on either or both of the bars e e, and indicating the distance between the said
bars, which corresponds to the existing position of the sliding piece or pieces.
3. In outside callipers comprising rods such as a a and bars such as ee a scale
rigidly connected at right angles to either bar whilst the other bar is able to move
parallel to the first bar along the said scale.
4. In an angle measuring instrument, comprising rods such as a a and bars such
as e e, sighting devices arranged on one of the rods a a, and a levelling device arranged
on that bar e, along which the sliding piece of the rod carrying the sighting device
is movable, this arrangement having for its purpose to adapt the instrument for
measuring vertical angles.
5. In an angle measuring instrument, comprising rods such as a a and bars such
as e e, a telescope rigidly connected to one of the bars e e, in combination with a
telescope connected with the other bar e, hut capable of rotation and an arc o, con-
centric to the pivot of the movable telescope, this arrangement having for its purpose
to adapt the instrument for measuring the angle at the apex of a triangle, the base of
which is formed by the distance between the bars e e.
6. In callipers the combination of two rods a a pivotted together and an are i
carrying a scale, substantially as described with reference to Fig. of the drawings.
7. The improved measuring instrument substantially as described with reference to
Figs. 1 to 5, to Fig. 7, and to Fig. 8 of the drawings.
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