Improvements in Drawing Compasses.
Year: 1896

page_text: Date of Application, 27th Nov., 1896-Accepted, 20th Mar., 1897
Improvements in Drawing Compasses.
A communication by GIOVANNI DERONESE FU FRANCESCO and ALFONSO
GUADAGNINI FU GAETANO, both of 30, Via Indipendenza, Bologna, in the
Kingdom of Italy, Manufacturer and Master Mariner, respectively.
I, WILLIAM PHILLIPS THOMPSON, F.C.S.. M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, 118, New Street, Birmingham
in the County of Warwick and 322, High Holborn in the County of Middlesex,
Civil Engineer, 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 :-
This invention has for its object various improvements in drawing compasses, by
means of which cleaner and more exact work can be executed with greater rapidity,
in accordance with inodern requirements.
The accompanying drawings represent with their details the improved instruments
which form the object of this invention.
Figures 1 to 7 show various forms of beam or knee compasses of precision with
a support.
These instruments have the remarkable advantage of great cleanness and
exactitude in the drawing seeing they do not perforate the paper, the central
point being more raised than the tracing point during the whole time a person is
drawing. When it is desired to bring the point p in contact with the paper, the
tracing point must be raised which is done by pressing the index finger on the
elbow a (Figure 1) of the external guide of the said tracing point; this operation
is very simple and does not derange the hold of the hand which rests on the
instrument.
In case it be necessary to keep either the ruling pen or the pencil raised, the
slides carrying these points are provided with a catch b, Figures 4 and 5, turning
on a pivot c; this catch has one end bent at a right angle to engage in a notch &
when the tracing point is pushed upwards. In this position the tracing points are
raised higher than the central point p.
By meaus of the foot or support P, the instrument is always raised above the
paper, and the draughtsman has only to depress it slightly in order to have it
ready for work. The tracing points exert a constant pressure by means of a small
spiral spring g but a weight may be substituted for the said spring. The foot or
support may be made in one piece, Figure 1, or be hinged at the points, or be
in sections at ss (Figure 1), or finally it may be made in the form of swivelling
bridges which may be set at right angles to one another as in Figure 2, or moved
into the same plane as in Figure 3. The foot or support may also be employed
with an ordinary or knee compass (Figures 6 and 7).
Figure 8 shows a drawing pen with au ink reservoir r which is very convenient,
more particularly for long lines and when the work is of long duration. The
reservoir r may be applied wheu desired.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. The combination with drawing compasses, of a support adapted to maintain
the central point in a raised position higher than the drawing or tracing points
during the use of the instrument, and means for raising the tracing points and
lowering the central point, substantially as hereinbefore described and shown in
the accompanying drawings.
2. The combination with a drawing pen, of an ink reservoir, substantially as
herein before described and shown in the accompanying drawings.
Dated this 26th day of November 1896.
W. P. THOMPSON & Co.,
Agents.