Year: 1888

page_text: Date of Application, 7th Feb., 1888
Complete Specification Left, 7th Nov., 1888
Complete Specification Accepted, 31st Dec., 1888
EDMUND LUCAS Gentleman 55 Oxford Gardens North Kensington W. do hereby
declare the nature of this invention to be as follows:-
The
Attached to an ordinary Drawing Board 1 place a double T Square so arranged
that it will slide up and down the board or can be raised by means of a pivot, hinge
or other similar contrivance, and for the purpose of fixing in any position I add vither
on the right or left a thumb scrow or similar appliance moveable at will.
heads also of the T square being in a like manner moveable at will. The main
advantage claim for my principle will be that greater steadiness is insured and
a firm basis is provided for conveniently fixing or placing triangles curves or other
appliances used in Mechanical Engineering Technical or Scientific Drawing.

page_text: EDMUND LUCAS of 55 Oxford Gardens North Kensington W. Gentleman 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:
To provide a better system for drawing lines, curves and angles as are producod
by means of a T square and its utilisation as a base for triangles and curves generally
used in Drawing either on paper stone or other similar appliance. The disadvantages
of the present system are that inaccuracies occur owing to the immense leverage
exerted on the shoulders of the square when the designer's pencil is travelling towards
the opposite end of the blade. Imperceptibly the power exerted and the enormous
leverage applied forces the T square out of position. And although the inaccuracy
may be slight, still it is frequently sufficient to utterly destroy the object for which
the drawing was intended. This will the more readily be seen when an enlargement
is required from a drawing or plan executed to scale.
The object of the present invention is to prevent this and obviate these disadvan-
tages. To carry out my invention I provide at the opposite end of the blade remote
from the shoulder, a clamp which slides freely backwards and forwards on the blade,
and is arranged with springs india rubber or like substance so as to bite the drawing
Board on the opposite side. Figure 1 of the accompanying Drawing shows the
T square with the clamp attached. Figure 2 shows a section of the clamp and
means by which the set screw acts. A represents the head of the screw; B screw;
C base or platform which keeps the blade in position; D blade of T square, E E springs
for the purpose of biting the board. Figure 3 section of clamp showing spring to
keep a taper T blade in position. Figure 4 represents a taper T square with lamp
attached. Figure 5 shows a drawing Board with T square in position and its use
as a base for curves, triangles parallel rulers and determining angles.
Having now particularly described and ascertained the nature of my said Inven-
tion & in what manner the same is to be performed I declare that what
I claim is
A new and novel method of fixing the T square by a clamp constructed and
operating substantially as shown and described.