An Appliance for Attachment to T Squares and the like for the Purpose of Maintaining the same in the Correct Position on the Drawing Board.
Year: 1893

page_text: Date of Application, 21st Dec., 1893
Complete Specification Left, 19th Sept., 1894-Accepted, 20th Oct., 1894
PROVISIONAL SPECIFICATION.
An Appliance for Attachment to T Squares and the like for the
Purpose of Maintaining the same in the Correct Position on the
Drawing Board.
I, SCOTT ADDISON, of 15 Mostyn Road, Bow, in the County of London,
Sanitary Inspector, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to construct an appliance which when attached to
Tsquares will prevent the same from becoming displaced and compel the working
edge of the blade to maintain its position. perpendicular to the working edge of the
drawing board when in use.
Now according to this invention I provide a clip or cramp which may be secured
to the end of the blade of a T square opposite the stock by a clamping screw and
to this clip or cramp I secure a spring or springs preferably having one or more
anti-friction rollers attached thereto which rollers are pressed by the spring or
springs against the edge of the drawing board thus keeping the stock of the square
firmly pressed against the working edge of the board and preventing the blade
from being forced out of the perpendicular by the pressure of the hand or arm of
the user.
Or I may attach one or more anti-friction rollers to a rod a pin passing through
a socket on the clip or cramp the said rod being of such a section as to prevent its
rotation in the said socket. I attach to the end of the said rod or pin a nut or
collar preferably the former and between the nut and collar I place a coiled
spring which tends to draw the anti-friction rollers towards the stock of the
Tsquare.
Or instead of using a clip or cramp I may use a piece of metal or other suitable
material having one or more slots therein through which pass one or more screws
or bolts to secure the same to the blade of the square this arrangement being
applicable to T squares the blade of which does not project beyond the edge of the
drawing board a sufficient distance to attach the cramp.
The cramp or slotted piece may have one or more spikes attached thereto for
extra security.
.
An ordinary straight edge may be converted into a T square by attaching an
appliance as herein before described to each end thereof.
The appliance herein described in no wise interferes with the free movement of
the T square up and down the board.
Dated this 21st day of December 1893.

page_text: COMPLETE SPECIFICATION.
An Appliance for Attachment to T Squares and the like for the
Purpose of Maintaining the same in the Correct Position on the
Drawing Board.
I SCOTT ADDISON of 15 Mostyn Road, Bow in the County of Middlesex
Sanitary Inspector 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 object of this invention is to construct an appliance which when attached to
tee squares and the like will prevent them from becoming displaced and compel the
working edge of the blade to maintain its position perpendicular to the working
edge of the drawing board when in use.
Now according to this invention I provide a clip or cramp which may be secured
to the end of the blade of a T square opposite the stock (or a similar cramp may be
secured to each end of a straight edge) by a clamping screw and to this clip or
cramp I secure a spring or springs preferably having one or more anti-friction
rollers attached thereto which rollers are pressed against the right hand edge of
the drawing board thus keeping the stock of the square firmly pressed against the
working edge of the board and preventing the blade from being forced out of the
perpendicular by the pressure of the hand or arm of the user.
Or I may attach one or more anti-friction rollers to a rod or pin passing through
a socket on the clip or cramp the said rod being of such a section as to prevent its
rotation in the said socket. I attach to the said rod or pin a nut or collar and I
place round the rod a coiled spring which tends to draw or force the anti-friction
rollers towards the stock of the T square.
Or instead of using a clip or cramp I may use a piece of metal or other suitable
material having one or more slots therein through which pass one or more screws
or bolts to secure the same to the blade of the T square this arrangement
being applicable to T squares the blades of which do not project beyond the edge
of the drawing board a sufficient distance to allow of the cramp being used the said
springs and rollers being attached to the said piece of metal.
The cramp or slotted piece may have one or more spikes attached thereto for
extra security.
An ordinary straight edge may be converted into a T square by attaching an
appliance as hereinbefore described to each end thereof.
The appliance herein before described in no wise interferes with the free
movement of the T square up and down the drawing board.
And in order that iny said invention may be fully understood I will proceed to
explain the same with reference to the accompanying sheet of drawings in which
Fig. 1 represents a plan of an appliance constructed according to this invention.
Figure 2. is side elevation of the same.
Figure 3 shews the appliance attached to a T square.
Figures 4 and 5 shew modified forms of the spring.
Figures 6 and 7 shew modified forms of the apparatus in which the antifriction
rollers are attached to a rod passing through a guiding bracket attached to the
cramp.
Figure 8 is side view of the appliance as fitted to T squares the blades of which
do not proiect beyond the edge of the drawing board.

page_text: Figures 10 and 11 shew respectively end view and plan of a modified form of the
apparatus shewn at Figures 9 and 10.
The same letters denote the same parts in all the figures.
a is a cramp preferably of the form shewn by Figures 1 2. and 3 and of any
suitable section preferably section as shewn to obtain the necessary strength with
the minimum amount of metal.
To this cramp is attached by rivets or other suitable means a bent spring b
having attached to each end thereof a bracket c in which rotates an antifriction
roller or rollers d ee are spikes inserted in the cramp a to hold the same securely
when attached to the square f by rotating the screw g by means of the head h
jis a metal disc attached to the screw g but not rotating therewith to prevent the
screw from injuring the square is the drawing board.
In the modified form of spring shewn at Figure 4 the said spring is bent to an
obtuse angle only.
The spring shewn at Figure 5 has attached thereto only one antifriction roller.
Figures 6 and 7 shew the roller bracket attached to a square rod m passing
through square holes in a bracket 'n the rollers being pressed against the edge of
the drawing board by a flat spring similar to that shewn at Figure 5 (see Figure 6).
or by means of a spiral spring 6 bearing against a collar m' attached to the rod m
at one end and against the bracket n at the other end.
When the appliance is to be attached to the blade of a T square which does not
project beyond the edge of a drawing board the cramp a is dispensed with and a
plate of metal al preferably flat substituted therefor.
I prefer to cast the metal in the shape shewn at Figures 8 and 9 having two
projections or lugs n¹ n¹ which answer the purpose of the bracket n shewn at
Figures 6 and 7 the bracket c and spring 6' being of the same construction as those
shewn by Figure 7 or the plate a¹ may be made plain and the bracket n secured
thereto by rivetting or other suitable means.
The plate al has two or more slots as therein to receive screws or bolts which
pass through the blade of the square and are provided with wing nuts to secure the
plate to the square.
The slots allow of the plate being adjusted to maintain the proper pressure of the
rollers d d against the drawing board.
It will be understood that in all cases it will be requisite to compress the spring b
slightly before clamping the appliance to the square.
The plate a' may be provided with spikes to steady it if desired.
In the modified form shewn at Figures 10 and 11 the plate a' is turned over at
the edges to receive a piece of elastic wire all to the ends of which are attached the
brackets c c the wire being bent downwards and outwards to form a spring as shewn.
at Figure 10.
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. In an appliance for attachment to T squares as herein before described the
combination of a clamp or clip a with a spring b having one or more antifriction
rollers d attached thereto by means of brackets c and a clamping screw g substan-
tially as and for the purpose specified.
2. In an appliance as hereinbefore specified the combination of a clip or cramp a
having a bracket n attached thereto a rod m sliding therein having a bracket
carrying one or more antifriction rollers attached thereto a spring 6 and a clamping
screw all substantially as hereinbefore described and shewn at Figure 6 of the
accompanying drawings.
3. The modified form of the appliance as claimed in Claim 2. substantially as.
hereinbefore described and shewn at Figure 7 of the accompanying drawings.
4. The modifications of the appliance as adapted to the blades of T squares
which do not project beyond the edge of the drawing board substantially as

page_text: herein before specified with reference to Figures 8 9 10 and 11 of the accompanying
drawings.
Dated this. 19th day of September 1894.
T. E. HALFORD,
11, Furnival Street, Holborn, London, E.C., Agent for the Applicant.