An Improved Centre Disc for Supporting the Points of Drawing Compasses.
Year: 1893

page_text: Date of Application, 24th Feb., 1893
Complete Specification Left, 22nd Apr., 1893-Accepted, 27th May, 1893
PROVISIONAL SPECIFICATION.
An Improved Centre Disc for Supporting the Points of Drawing
Compasses.
We, BENJAMIN HODGETTS STOKES, of 21 Bryantwood Road, Drayton Park
Highbury, in the County of Middlesex, Draughtsman, and CHARLES HENRY
WILLATT, of 46 Bedford Street, Strand in the City of Westminster, Hotel
Proprietor, do hereby declare the nature of this invention to be as follows —
"
As ordinarily constructed centre discs, or as they are termed "horn centres
are made with a number of small points which enter the paper to prevent the
shifting of the disc. Now the marks made by these points are nearly as objectionable
as the marks of compass points they are employed to prevent. In addition to this,
should the square accidentally come in violent contact with the disc the paper is
torn and the drawing spoiled.
According to this invention we construct a disc that adheres to the paper by
frictional contact, even when the drawing board is tilted to a considerable angle.
Such a device consists of a discs of xylonite, celluloid, horn, mica or other suitable
transparent material to one face of which is secured a thin ring of india rubber or
other suitable material. In some cases such a ring may be applied to each. side of
the disc so that it may be used on either side at will. In use this is placed upon
the drawing with the said ring downwards and in contact with the paper to which
it is found to cling sufficiently to prevent slipping out of position of the device.
One advantage attending the use of this device is that the centre may be trans-
ferred upon the point of the compass from one point where it is intended to strike
a number of concentric circles or arcs of circles to any point where it is desired to
repeat the operation as in the case of drawing a Gothic window. With this device
the compasses may be extended and contracted at pleasure as in the case of
striking concentric circles or arcs of circles without the device being displaced in
the least.
Doted this 24th dor of Wahr 1902
CASTLE SMITH,
"Invention" Office, 54, Fleet Street, London, E.C.,
Agent for the Applicant.
COMPLETE SPECIFICATION.
An Improved Centre Disc for Supporting the Points of Drawing
Compasses.
We BENJAMIN HODGETTS STOKES of 21 Bryantwood Road Drayton Park
Highbury in the County of Middlesex Draughtsman and CHARLES HENRY
WILLATT of 46 Bedford Street Strand in the City of Westminster Hotel
Proprietor 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 :-
"
According to the present ordinary and customary method of construction and
fitment centre discs or as they are most commonly called "horn centres
are made
or provided with a number of small metallic or other points which project from
one of the faces of each disc and are caused to enter the paper or other material
to prevent during the required employment of the same the slipping of the disc or
any shifting of its position and it is therefore obvious that in and by the use of a disc

page_text: so constructed and fitted as aforesaid each of the points on such disc must and does
make a small hole in the paper or other material thereby marking the same to the
detriment of the drawing and the effect thereof is almost even if not quite as
objectionable as the single hole that would be made by the point of the central leg
of the drawing compass which mark it is that this disc is made and employed to
prevent. Furthermore if and when any one or more of the drawing implements or
other articles comes or come into violent or other contact with the disc when so
fixed on the paper or other material by its points as aforesaid it is extremely
probable even if not absolutely certain that the paper or other material will be torn
or otherwise damaged to some extent.
Now the objects of this our invention are to remedy this evil and to obviate this
danger hereinbefore mentioned and to provide a centre disc for supporting the
points of drawing compasses that will not cause or allow any such marks as afore-
said to be made on the paper or other material and that shall be very safe and
efficient and convenient in use as also extremely simple and cheap in construction.
To carry out this object a disc is made of horn xylonite celluloid or any other
transparent or semi-transparent material such as will allow and fulfil the two
governing conditions in the use thereof that is to say it must be sufficiently
transparent to allow the proposed central point to be seen therethrough and it
must allow the point of the compass to be engaged therein and to be retained in
one desired position thereby and this disc may be of any desired size and shape
and may be as thick or as thin as may be convenient or expedient having regard
chiefly to the particular material of which the same is made. Round and it may
be on the edge or periphery of this disc or it may be near such edge or periphery
on one face of this disc is placed and secured in any convenient manner and by any
adhesive substance or otherwise a strip or ring of any appropriate material such
for example as cloth leather gutta-percha and the like but preferably perhaps of
india rubber which strip or ring may be of any desired size both in breadth and
depth and of any suitable shape in cross section but it is most conducive to the
safe and efficient and certain performance by the same of its required function
hereinafter described that its outer surface should be flat and plane and parallel
with the face of the disc. When the strip or ring is on the edge or periphery of
the disc it is generally most convenient that it should project from and beyond
both of the faces of such disc and when the strip or ring is near such edge or
periphery on one face of the disc it is perhaps also generally most convenient
that another similar strip or ring should be placed and secured on the other face
of such disc in the same manner or otherwise so that this disc so fitted can be used
interchangeably with either face uppermost. The disc is preferably perhaps of a
circular shape but it may also be made of any other shape as may be deemed
expedient or convenient in each particular case and when the strip or ring is near the
edge or periphery of the disc it may follow the contour of such edge or periphery at
the desired distance therefrom or it may not follow the same as may be preferred
in each particular case.
When the disc so made and fitted as hereinbefore described has been placed
upon the paper or other material in the proper position so that the proposed central
point can be seen therethrough the interposed strip or ring will be found to cling
or adhere by its inherent frictional capabilities and its contact to the surface of
such paper or other material quite sufficiently to prevent the disc slipping or
shifting its position by accident while in use and therefore this our improved
centre disc can be safely employed for its purpose hereinbefore described while it
can easily be moved from one position to another even upon the point of the
compass without any danger of tearing or damaging the paper or other material.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. The combination with a disc of horn or other material of a strip or ring of

page_text: india rubber or other material substantially as and for the purpose hereinbefore
described and declared.
2. The centre disc for supporting the points of drawing compasses substantially
as herein before described and set forth.
HART & Co.,
186, Fleet Street, London, E.C., Agents.