An Improved Combined Square and Protractor.
Year: 1898

page_text: An Improved Combined Square and Protractor.
1, JOHN ALEXANDER ROONEY, of 1, Aston's Place, Fleet Street, Dublin, Ireland,
Engraver, do hereby declare the nature of this invention to be as follows:-
This invention has for its object a combined square and protractor whereby
angles as set out by means of the protractor can be readily drawn. Also, the
instrument can be used as an ordinary T square when necessary.
According to this invention a protractor is mounted upon a suitable base piece
and at its centre a moveable arm or blade is pivoted in a groove or slot formed
in the said base piece. A slot is formed in the moveable arm or blade so that
one edge of the slot forms a correct radial line from the centre of movement
and therefore forms a correct radial line from the centre of the protractor.
The base piece or head is constructed with one half removable and when in
use as a protructor one half is removed so that the blade is directly on the paper
and the angle can be set out with greater accuracy.
be drawn
It will thus be seen that by placing the instrument upon the paper with the
centre of the protractor at the point from whence a line at a certain angle
is to be drawn, the movable arm or blade can be turned until the edge of the
slot marks the desired angle on the protractor, when the line can
along said edge of the slot. Preferably the movable arm or blade is marked
with a scale so that the desired angular line can be drawn of definite length at
one operation.
By turning the movable arm to mark 90 degrees the instrument will serve the
purpose of a square. The movable arm may if desired be cut out so as to abut
against the base piece when 90 degrees is reached and prevent further movement
or a pin may be fitted in the base piece so that it can be caused to engage with
the movable arm or blade and retain it in the right angular position for use as
a T or other square. If desired means may be provided for retaining the
movable arm or blade in position at any angle.
Several tongues or clips may be arranged upon the base piece so as to act as
supports on the edge of the drawing board. These are pivoted so that they can
be turned down out of the way when not in use, preferably into slots formed in
the said base piece.
When applying this instrument as an ordinary protractor the blade may be
fitted to act as a ruler for use in marking off the line at the desired angle.
The working edge of the blade is bevelled so as to be available for use either
by pen or pencil.
In a modified arrangement there is only half the blade, the blade being shaped
30 that its working edge is in a radial line from the centre of the protractor,
instead of being arranged to form one side of a slot as in the above described
arrangement.
In another modification suitable more especially for ordinary protractors the

page_text: parts are made of sheet metal connected together by means of a suitable rivet
or pin and suitably graduated.
The instrument.can be made of wood or metal as desired. The head or base
piece may be of mahogany or any wood and the movable arm or blade of lance
wood or other wood suitable for the purpose and a metal edging may be fitted
thereto. Or if desired the head or base piece may be of metal and the movable
arm or blade of flexible steel or the like.
1
T3-1
1000
An Improved Combined Square and Protractor.
I, JOHN ALEXANDER ROONEY, of 1, Aston's Place, Fleet Street, Dublin, Ireland,
Engraver, 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 a combined square and protractor whereby
angles as set out by means of the protractor can be readily drawn, the instru-
ment being also adapted for use as an ordinary T square.
According to this invention, a protractor mounted upon a suitable base and
at its centre a movable arm or blade is pivoted. One edge of the blade forms
a radial line from the centre so that the angle through which the blade may be
moved is correctly indicated upon the protractor.
The base or head is formed in two parts, the lower one of which can be
detached leaving the instrument with the blade level with the bottom of the
head allowing the blade to lie flat on the paper.
When the instrument is used as a T square the head is completed and the
blade is fixed at an angle of 90 degrees to the head the head resting against the
side of the drawing board in the ordinary manner. Parallel lines at any desired
angle can also be drawn on fixing the blade in various positions.
In order that the invention may be more clearly understood reference is had
to the accompanying sheet of drawings in which Fig. 1 is a plan of an instru-
ment constructed according to my invention, Fig. 2 is a cross section of the
head on the line 7, y, and Fig. 3 shows another form of blade.
The head is formed in the two pieces A and A, the lower one of which is
detachable from the upper. Two parts are fitted together as shown in Fig. 2
by means of buttons such as a on the lower part engaging in slots in the
plates a¹. One end of each slot is enlarged to allow the button to pass through
and on sliding the lower part of the head into position the two parts are secured
together. Any other form of detachable connection may be employed.
To the part the protractor B is fixed, the head being grooved or cut away
to receive the protractor. The protractor is marked in the usual manner to
indicate the angles. C is the blade which is pivoted at c to the protractor
accurately at its centre and in the arrangement shown in Fig. 1 one edge of
the blade is exactly radial. As shown in Fig. 3, the blade C is provided with
The blade is marked with the
the slot one edge of the slot being radial.
scale which allows a line of any pre-determined length to be drawn with
accuracy. The blade is arranged flush with the bottom of the part A so that
when the lower part of the head is detached the instrument lies flat on the paper.

page_text: To secure the blade in position at any desired angle a small clamp D is
employed provided with the thumb screw d. When the arm is turned into the
desired position the clamp is employed to fix it to the inner edge of the pro-
tractor.
The edge of the blade may be bevelled if found desirable and may be of any
material such as wood, or metal. The head may also be made of any material
found desirable. If of wood the blade may be provided with a brass edge on
which the scale can be placed.
The pivot of the blade should be tubular in order that in marking a line at
any desired angle the central point may be seen.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is;-
(1) An improved drawing instrument comprising a protractor fitted to a suit-
able base and a blade pivoted centrally to the protractor having one radial edge
adapted for drawing purposes, substantially as described and for the purposes
specified.
(2) An improved drawing instrument comprising a protractor, a blade pivoted
to the protractor having one radial edge, and a head carrying the protractor
and blade formed with a lower detachable part enabling the instrument to be
used as a T square or protractor as desired, substantially as described and for
the purposes specified.
(3) The improved drawing instrument comprising a protractor, a centrally
pivotted blade, means for securing the blade at any desired angle, and a double
head carrying the blade and protractor, constructed substantially as described
and shown and for the purposes specified.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.