Improvements in Mathematical Instruments known as Beam Compasses.
Year: 1892

page_text: Date of Application, 1st Dec., 1892
Complete Specification Left, 23rd Aug., 1893-Accepted, 14th Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in Mathematical Instruments known as Beam
Compasses.
1, JAMES PORTER MAGINNIS, Civil and Mechanical Engineer of No. 9 Carteret
Street Queen Anne's Gate, in the City of Westminster, S.W. London, do hereby
declare the nature of this invention to be as follows:-
I employ tubular parts of suitable forms to be used in conjunction with an
ordinary lead pencil in such a manner that the pencil becomes the beam, one
tubular part being made to carry at right angles to the beam a metal point and the
other tubular part of "T" form, one limb of which fits on the beam and the other
limb at right angles to it being adapted to carry a pencil or pen or a second metal
point. In order that the distance between these points or between the first named
point and the pencil or pen may be regulated I make the tubular parts of such a
form that they will slide along the pencil beam, and remain in any desired position,
or one tubular part may be stationary whilst the other is capable of sliding. For
describing circles or arcs of greater radii than the length of a lead pencil will
allow I connect two or more pencils together by means of tubular pieces into
which the ends of the pencils are thrust end to end till the desired length' of beam
is obtained.
COMPLETE SPECIFICATION.
Improvements in Mathematical Instruments known as Beam
Compasses.
JAMES PORTER MAGINNIS, Civil Engineer 9 Carteret Street, Westminster
London S.W. do hereby declare the nature of this invention and in what manner
the same is to be performed; to be particularly described and ascertained in and by
the following statement :-
In these improvements I employ metallic or other tubular parts made in such a
form and in such a manner that they will readily slide along or remain stationary
in any position on an ordinary pencil such as is used by artists, draughtsmen and
others. These tubular parts A, A, may be of circular polygonal or other section
and are made with two limbs in the form of a "T" or L" so that when a
pencil B is placed in one limb there is a second limb at right angles to the pencil.
If two of these tubular parts A, A, be placed on a pencil B, such pencil becomes
the "beam" and if a needle or other point C, be placed in one of the vacant limbs
and a pencil or pen D be placed in the other vacant limb the whole becomes a
beam compass and may be used for the purpose of describing circles. The distance
between these limbs may be varied by sliding one or other of them along the
or pencil used as such, and as the tubular part may be slit or cut either
partially or from end to end sufficient elasticity is obtained to grip the "beam
firmly or to allow of the said sliding motion. Or one tubular part may be provided
with an internal screw in one of its limbs into which the end of the beam may be
screwed and thus held securely whilst the other tubular part is free to move as
described.
❝ beam
"
"
For describing circles or arcs of greater radii than the length of a single pencil
beam will allow I connect two or more pencils together by means of suitable

page_text: tubular pieces E into which the ends of such pencils are thrust end to end till the
desired length of beam is obtained.
Having now particularly described and ascertained the nature of my said inven
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The employment of one or more pencils to be used as the beam of a beam
compass.
2. The employment of suitable tubular parts to be used in conjunction with a
pencil or pencils the combination forming a mathematical instrument known as a
beam compass.
3. The employment of suitable tubular parts for the purpose of joining together
end to end two or more pencils so as to form a "beam" of any desired length.
Dated this 23rd day of August 1893.
JAMES P. MAGINNIS.