Improved Dividers for Mathematical and other Purposes.
Year: 1891

page_text: Date of Application, 28th Nov., 1891
Complete Specification Left, 29th Aug., 1892-Accepted, 1st Oct., 1892
PROVISIONAL SPECIFICATION.
Improved Dividers for Mathematical and other Purposes.
I LEONARD GODFREY PINNEY THRING of 57 Bridge Street in the City
and County of Cambridge Undergraduate do hereby declare the nature of this
invention to be as follows:-
This my invention relates to an improved dividers for mathematical and other
purposes and my invention consists in an instrument for bisecting lines in a simple
manner and with great facility and the said instrument possesses the advantage
that the extremities or points of the legs are in one and the same straight line the
advantage of which is obvious.
In carrying my invention into practice I form the instrument in the manner
hereinafter described and set forth."
The legs which form the outer legs of the dividers are hinged together by means
of a suitable joint at one of their ends and the angle thus formed is bisected by a
centre or third leg.
The hinged fulcrum joint at which the outer legs are connected together is
provided with a projecting pin which engages in a slot in the central leg just
mentioned.
A. rectilinear frame which is formed of four strips or bars (preferably flat) the
said frame thus forming a parallelogram is attached at one of its angles to a pivot
upon the central leg the opposite corner being provided with a projecting pin
which traverses the upper portion of the slot in the central leg before mentioned.
The two pins which traverse the slide are connected by a link so as to move
simultaneously.
As the lower corner of the parallelogram turns upon a fixed pivot it follows that
a shortening of the longitudinal axis of the same caused by moving the upper angle
pin downwards towards the point must cause a corresponding increase of the length
of the transverse axis.
The angles at the extremities of the sides of the parallelogram are connected to
the outer legs of the dividers by short links in such a manner that the lengthening
of the transverse axis will cause the points of the outer legs to move farther from the
point or lower end of the central leg and a shortening of the said axis will inversely
cause the outer points to approach nearer to the central one. As the lengthening
or shortening of the said axis is uniform upon both sides of the vertical axis of the
parallelogram it follows that the measurement between the points of the outer legs
is bisected by the point at the extremity of the inner one.
The proportions and arrangement of the several parts may be varied without
departing from the spirit of my invention.
Dated this 28th day of November 1891.
HORN & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Dividers for Mathematical and other Purposes.
I, LEONARD GODFREY PINNEY THRING of 67 Bridge Street in the City and
County of Cambridge, Undergraduate, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
This my invention relates to improved dividers for mathematical and other

page_text: purposes and my invention consists in the details and combinations of the same
hereinafter described.
In order that my invention may be readily understood reference is made to the
accompanying drawings in which
:-
Figure 1. is a front view of a pair of bisecting dividers made in accordance with
my invention, and
Figure 2. is a modification of the same.
My invention is intended to be applied for bisecting right lines and the object of
my said invention is to so construct the instrument that the points shall always be
in one and the same straight line.
My improved dividers as illustrated in the accompanying drawings consist of a
central leg A the lower extremity of which forms the bisecting point a midway
between the outer legs B B. The said outer legs B B are connected at the upper
ends to a pin e movable in a slot d e f g h is a parallelogram the sides of which are
respectively equal in length to the portion of the legs B B between the
points e b
The several connecting links I. J. K. are also equal to each other.
The parallelogram efy his bisected by the centre of the middle leg A, and the
outer legs B B being parallel with the sides efgh of the said parallelogram
respectively the angle formed by the said outer legs is also bisected. It follows
therefore that the points of the outer legs are equidistant from the central
point a, in other words the distance between, the points bb of the legs B B is
bisected at a.
The pivot is stationary consequently an increase of the lateral dimensions
between the points of the said parallelogram efgh will cause a corresponding
shortening of the vertical dimension between the points e, (as shown in dotted
lines in the figure). This motion causes the pine to traverse the slot d in the
central leg and through the link I the pin e connected thereto, thus the fulcrum or
pivot of the legs B B is lowered according to the increase or enlargement of the
angle between the legs B B and etce versa and the points a, b b are caused to retain
their alignment.
The modification illustrated in Figure 2 is similar in principle to that form just
described, the legs B', B' being in this form parallel to the bisecting or central
leg A and the action of the same will be readily understood from the figure by all
skilled in the art without detailed description.
The details of construction of the several parts and the connections thereof may
be varied without departing from the spirit of my invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is:
The improved dividers for mathematical and other purposes constructed,
arranged and operating substantially as described and illustrated in the
accompanying drawings.
Dated this 28th day of August 1892.
HORN & SON,
Applicant's Agents.