An Appliance to be used for Copying Drawings or other: Subjects, and for Sketching in Perspective.
Year: 1892

page_text: Date of Application, 4th Aug., 1892
Complete Specification Left. 16th Jan., 1893-Accepted, 4th Mar., 1893
PROVISIONAL SPECIFICATION.
An Appliance to be used for Copying Drawings or other: Subjects,
and for Sketching in Perspective.
We GEORGE WILLIAM THOMAS of No. 1 Trewern Villas Fulham Road
Fulham Estate Agent and ROWLAND BROTHERHOOD of the same address
Engineer do hereby declare the nature of this invention to be as follows:-
:-
It consists of a T square or ruler fitted with a sliding leaf attached perpen-
dicularly and intended to be used in conjunction with an eye piece and convenient'
graduated scales.
A drawing board or other plane surface upon which a drawing can be made is
fitted on the side nearest the operator with a graduated scale and the T square and
leaf contain on the inside or ruling edge similar scales. The apparent dimensions
of the object to be sketched are read off by means of the perpendicular graduated
leaf through the eye piece (which is conveniently fixed so as to exactly face the
centre of the sketch) and transferred by means of the horizontal scales to the
drawing surface.
Dated this 3rd day of August 1892.
GEO. W. THOMAS.
R. BROTHERHOOD.
COMPLETE SPECIFICATION.
An Appliance to be used for Copying Drawings or other Subjects,
and for Sketching in Perspective.
We, GEORGE WILLIAM THOMAS, of No. 1, Trewern Villas, Fulham Road, in
the County of Middlesex, Estate Agent, and ROWLAND BROTHERHOOD, of the
same address, 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 :---
The present invention relates to improvements in appliances for use in copying
drawings or in making perspective drawings from models or from nature; and
consists in the combination of a drawing board, or its equivalent, to support the
sheet upon which the drawing is to be made, a fixed eye piece independent of the
movements of the draughtsman's head, a moveable vertical scale for measuring
heights in the picture plane or in the drawing to be copied, and a transverse scale
adapted to move with the vertical moveable scale above mentioned, from which
transverse scale the heights read off on the former can be transferred to the sheet
along a vertical which has been laid down there automatically.
In order that the invention and the means by which it is to be carried into
practical effect, may be thoroughly understood, we will now describe it and them in
detail, referring in so doing to the accompanying figures which are to be taken as
part of this Specification and read therewith.
Fig. 1 is a perspective view illustrating the construction and use of the invention.
It is shewn as mounted upon an ordinary tripod stand.
Fig. 2 is a side elevation partly in section, omitting the stand illustrated in
Fig. 1.
Fig. 3 is a plan corresponding with Fig. 2.
The stand a may be of any construction. The drawing board b is shewn as
provided with a screw on its under side, by which it can be held to the head of
the stand. Any other equivalent device may be used for the purpose.

page_text: i
c is the sheet of drawing paper. It is held down upon the drawing board in the
usual way.
It must be pointed out that the drawing board and sheet of paper illustrated
may be modified to any extent provided, that there is a surface capable of
supporting the sheet' upon which the drawing is to be made, and which is provided
with a guide of some kind in or upon which the transverse scale can be moved
to and fro:
d is a straight.edge. The invention requires that, it should be moveable upon
..the board from one side to the other, with its edge or edges always at right angles
with the front edge of the board. To meet such requisition, the straight edge is
fitted with a head after the manner of a T-square, which head is kept in contact,
in some way or other, with the board. Our invention does not limit us in respect
of the means which we employ to keep the head in contact with the board, and so
long as the said means are capable of providing for the motion of the straight edge
from one side of the board to the other, it being maintained steadily at a right
angle with the direction of such motion throughout the latter, any suitable device
or arrangement may be adopted. The means illustrated in the figures are as
followse is a rod which is held parallel with the front edge of the board' by a
pair of brackets e', e. d' is a tubular clip. It embraces the rode and is made
fast to the end of the straight edge; its axis, which is coincident with that of the
rod e, being at right angles with the straight edge d.
L.
1.
f is a scale near the front edge of the board. This scale may be upon the
surface of the board or upon a suitably bevelled surface, as illustrated: The latter
is preferable as it is out of the way of the paper and will not be rubbed by the
straight edge.
d is a scale upon the left hand edge of the straight edge d and is transverse to
the drawing board b.
g is a second straight edge; and g¹, a scale on its left hand edge. It is hinged
directly, or otherwise, to the outer end of the straight edge d, in any con-
venient way, provided that the two left hand edges are always in the same
vertical plane.
Some suitable device for setting the scale at any given angle with the sheet c
is required, and this may be of any convenient kind. The one illustrated is as
follows: - is a rack pivotted either to the straight edge d, or to the block described
in the next paragraph, and to which block the straight edge is hinged.
h is a stud which can be screwed into the straight edge g. The figures shew
the latter as hinged to a block y'. This has a long tongue which engages in a
groove cut in the face of the straight edge d. The object of this tongue-and-
groove arrangement is to provide for the straight edge g being moved away from
or brought nearer to the draughtsman's eye. The connection between the
block and the straight edge d'niay be of any suitable type provided that it
is telescopic.
i is an eye piece of any convenient construction capable of aligning the focus of
the eye with any given point in the object to be drawn. It is supported at a
suitable height by a rod which fits into a socket in the corner of the drawing
board to the left hand of the draughtsman. It may occupy any other convenient
position, for instance to the right hand of the draughtsman, and it is to meet such
a case that both the scales d', g', are repeated on the right hand edges of the
respective straight edges d and 9. We wish to draw attention to the fact that
according to our invention, the eye piece is held stationary to and by the drawing
board or its equivalent, so that instead of it being brought to the eye, the eyes is
brought to it.
The scales, d and g¹ are all replicas of each other. The figures shew them as
running in opposite directions from a central zero.
The invention constructed as above described is used as follows:-If it is a
drawing instead of au object that has to be copied, it is mounted vertically upon a
wall or easel, or otherwise, as may be convenient. Or, instead of mounting..the..

page_text: drawing vertically, it may be laid down horizontally or at any intermediate angle,
and the straight edge g be laid upon it. It must be pointed out that the process, of
making a perspective drawing of an object and copying a drawing supported in.
the vertical plane are identical, inasmuch as in the former case the draughtsman
copies what he sees in what is technically known as the picture plane and
which is always treated as vertical, and in the latter case, he copies a vertical
picture..
The paper c is stretched or mounted on the board d, and the latter placed in.
position. The straight edge is next fixed. If a perspective drawing is to be-
made, it is fixed vertically, and adjusted in respect of its distance from the
draughtsman according to the scale upon which the drawing is to be made. The
further away it is from him, the larger will be the picture or copy produced on
the paper c.
The eye piece is also fixed; in the left hand corner, if the draughtsman is-
going to sight with his left eye, or in any other position, on or off the board, care
being taken that it is always fast to the board and independent of the motion of
the draughtsman's head.
Let it be supposed that the object to be copied is a house. The top left hand
corner of the roof is sighted and the scaled moved along the board until the-
scale g cuts the line of sight. The intersection is read off the scale and trans-
ferred to the paper e from the scale which, it will be borne in mind, is the
replica in the horizontal plane of the other in the vertical plane. This trans-
ference gives the perspective position of the point sighted; and the edge of the
scale is the projection of the vertical line containing the said point, for the
intersection above mentioned scaled the height of it in the picture plane, and as
the scales g', dare in the same plane, the perspective position on the sheet c is
found automatically without any trouble with base line, horizon line vanishing
lines or with any of the usual apparatus of the perspective draughtsman. The
opposite or top right hand corner, if the line between them is unbroken, is next
sighted by means of either scale on the straight edge'g and transferred to the
paper along the corresponding scale on the straight edge d. The line joining these
two projections on the paper is the roof line in perspective. The other points are
projected in the same way and joined by lines as required. Curved lines are
followed in the same way; as many points in the course of them being projected
as the draughtsman may consider necessary to enable him to trace the perspective
representation of the original.
When a drawing is to be copied full size, it is held close to the plane in which
the scale on the straight edge g moves, or the latter can be laid upon it as already
explained. Under such circumstances, the eye piece is dispensed with.
If it is
desired to produce a drawing on either an enlarged or a reduced scale, a larger or
smaller scale on the straight edges 9 and d may be used, or those present be
read larger or smaller. The scale f is used for enlarging or reducing horizontal
distances.
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 of a support for the sheet upon which the drawing is to be
made, a vertical scale capable of motion to and fro between the said sheet and
the original or the picture plane, and a transverse scale capable of motion
to and fro over the said sheet, the two scales being always in the same vertical
plane.
2. The combination of a support for the sheet upon which the drawing is to be
made, a pair of vertical scales capable of motion to and fro between the said sheet
and the origiral or the picture plane, and a pair of transverse scales capable of
motion to and fro over the said sheet, the two pairs of scales being always in the
same vertical planes, respectively.

page_text: 3. The combination of a support for the sheet upon which the drawing is to be
made, a vertical scale capable of motion to and fro between the said sheet and the
original or the picture plane, a transverse scale capable of motion to and fro over
the said sheet, the two scales being always in the same vertical plane, and an
eye piece.
4. The combination of a support for the sheet upon which the drawing is to be
made, a pair of vertical scales capable of motion to and fro between the said
sheet and the original or the picture plane, a pair of transverse scales capable of
motion to and fro over the said sheet, the scales of each pair being alway's in the
same vertical planes, respectively, and an eye piece.
5. The combination of a support for the sheet upon which the drawing is to be
made, a transverse scale or scales capable of motion to and fro over the said sheet,
a vertical scale or scales capable of motion to and fro between the said sheet and
the original or the picture plane, the vertical scale or scales being respectively in
the same vertical plane as the transverse scale or scales, and a telescopic device
by which the vertical scale or scales can be moved away from or brought nearer
to the draughtsman.
7. The combination of support for the paper upon which the drawing is to be
made, a transverse straight edge having a scale on one or both edges and a second
straight edge graduated to correspond therewith and pivotted directly or indirectly
to that end of the former which is opposite to the draughtsman in such a way that
the scales are, respectively, in the same vertical plane.
Dated this 16th day of January 1893.
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, W.C.,
Agents for the Applicants.
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, W.C.,
Agents for the Applicants.