A NEW OR IMPROVED INSTRUMENT FOR DIVIDING CIRCLES OR ARCS OF CIRCLES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, Patent.
Agents, of 67, Strand, in the City of Westminster, Civil Engineer, do hereby declare
the nature of the said Invention for A NEW OR IMPROVED INSTRUMENT FOR DIVIDING
CIRCLES OR ARCS OF CIRCLES, a communication to me from abroad by F. A. Mora,
of Senlis, France, to be as follows:-
This invention relates to instruments for dividing circles or ares of of circles into
equal or proportional parts.
The improved instrument chiefly comprises a rule, preferably rectangular in
section and divided on one or more of its sides into equal or proportional parts
according to any desired system.
A runner or slide is adapted to slide along the said rule and provided with a
slot, one edge of which may be made to coincide with any of the divisions of the
rule, which divisions correspond to the number of parts into which the circle is to
be divided.
The runner may be secured at any part of the length of the rule by means of a
screw, and carries a roller placed perpendicular to the rule and having a radius
equal to one division of the rule; for instance one inch, if the rule is divided into
inches.
.
This roller has on its circumference a small pin, pencil, or pen, which at every
revolution of the roller makes a mark on the paper or sheet over which the scale
is carried.
At one extremity of the rule (where the division begins) is mounted a screw or
pin perpendicular to the rule and adapted to place the rule at various heights
above the sheet to be divided, the said pin or screw being pointed at the lower
end and serving as axis of rotation for the rule.
For dividing a circle or circular arc, the pivotal pin is placed in the centre of
the arc and the runner secured at that division of the rule which indicates the
number of parts into which the circle is to bo divided.
The rule is then turned, so that the roller makes a mark at every revolution,
which marks correspond to the desired divisions of the arc or circle.
OUL
1004

page_text: I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, Patent
Agents, 67, Strand, Westminster, Civil Engineer, do hereby declare the nature of
the said invention for A NEW OR IMPROVED INSTRUMENT FOR DIVIDING CIRCLES
OR ARCS OF CIRCLES and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
At one
-
The invention relates to an instrument for dividing circles into equal parts. It
is illustrated in the accompanying drawing and consists of a flat or square rule A,
marked off on one of its sides into equal parts of any desired measure.
end of this rule is fixed a perpendicular support B terminating in a sharp point.
Along the rule works a slide C having a side opening, the said slide carrying
underneath, a pin on which a small wheel D turns, the radius of such wheel boing
equal to the unity of the measure marked off on the rule. The wheel bears an
indentation, projection, or other mark serving to indicate each revolution.
DIRECTIONS FOR USING THE¸ I
INSTRUMENT.
The perpendicular support B being placed in the centre of the circumference to
be divided into, say 17 equal parts, the slide is placed at the number 17; all that
is then necessary is to describe with the wheel a circumference concentric to the
one to be divided. As the wheel describes the circle it will mark off the 17
divisions by the application of the geometrical theorem that circumferences are
proportional to radii; the division of angles is based on the same theorem.
The instrument may be made in any suitable material.
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:
In the construction of an instrument for dividing circles, the combination of the
divided rule A, the slide with opening C, and the wheel D substantially as
described for the purposes set forth.
Dated this 20th day of December 1884.