Improvements in Set-squares, Protractors, Scale-rulers, Protractor- rulers, and Rulers.
Year: 1888

page_text: Date of Application, 6th Apr., 1888
Complete Specification Left, 29th Dec, 1888
Complete Specification Accepted, 5th Feb., 1889
PROVISIONAL SPECIFICATION.
Improvements in Set-squares, Protractors, Scale-rulers, Protractor-
rulers, and Rulers.
I, THOMAS HENRY BARRODALE, 7 Willow Avenue, Sandon Road, Edgbaston,
Birmingham, Government Certificated Schoolmaster, do hereby declare the nature of
this invention to be as follows:-
The marking of Set-squares, Protractors, Scale-rulers, Protractor-rulers and rulers
with lines straight or curved so placed and arranged as to be useful for the measure-
ment and construction of straight lines being the arms of angles and for the
measurement and construction of those aforesaid angles in such a manner that the
length of one arm of any angle or angles may be set off directly from the edge of
the Set-square, Protractor, Scale-ruler, Protractor-ruler or ruler according to some
scale or proportion indicated thereon without moving the Set-square, Protractor, Scale-
ruler, Protractor-ruler or ruler from the position required for the measurement or
construction by means of the Set-square, Protractor, Scale-ruler, Protractor-ruler or
ruler of the angle itself or angles themselves and without the aid of dividers,
compasses or any other instruments whatever oxcepting a pen or pencil. This is
effected by making the zero-point of the scale of linear measurement coincident
with the angular point or vertex of the angles measured and making both the scale
of linear measurement and the scale of angular measurement extend either both to
the right and left, to the right only or to the left only of the zero point.
1 1000

page_text: Improvements in Set-squares, Protractors, Scale-rulers, Protractor-
rulers, and Rulers.
I, THOMAS HENRY BARRODALE, 7 Willow Avenue, Sandon Road, Edgbaston,
Birmingham, Government Certificated Schoolmaster 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 consists in the marking of set-squares, protractors, scale-rulers,
protractor-rulers and rulers with lines straight or curved so placed and arranged as to
be useful for the measurement and construction of straight lines being the arms of
angles, and for the measurement and construction of those aforesaid angles, in such a
manner that the length of one arm of any angle or angles, and also the direction or
length of the arm of the supplement to that angle, or supplements to those angles
may be set off directly from the edge, or edges, of the set-square, protractor, scale-
ruler, protractor-ruler, or ruler according to some scale or proportion indicated
thereon, without moving the set-square, protractor, scale-ruler, protractor-ruler, or
ruler from the position required for the measurement or construction of the said
angle itself, or angles themselves by means of the angular indications marked on the
set-square, protractor, scale-ruler, protractor-ruler, or ruler. Such construction
or measurement is to be effected without the aid of any other instrument excepting
a pen or pencil.
For this purpose, I mark one or more of the edges of the set-square and protractor
with any regular or equal divisions for any form of plain scale, more particularly
inches and parts of an inch, and make such scale extend either the whole length of
the edge or any portion of it.
Such scale of linear measurement may extend either to the right of the zero point,
or to the left of the zero point, or both to the right and left of the zero point of the
said scale.
From the other edges of the set-square and protractor, I draw straight lines, longer
or shorter as may be determined, radiating at intervals of one or more degrees or
parts of a degree from the zero point of the aforementioned scale of linear measure-
ment, thus making the zero point of the said scale of linear measurement coincident
with the angular point or vertex of the series of angles marked on the set-square
or protractor.
I place the said zero point (a) at any point in one of the edges of the set-square
which is not one of the angular corners of the set-square; more particularly at the
middle point of the hypotenuse or long edge; (b) at any point in one of the long
edges of the protractor which is distant from the corner points of such edges; more
particularly at the middle point of the long edge.
From any one or more of the divisions of the scale or scales of linear measurement

page_text: indicated on the edge or edges of a protractor-ruler* or scale-ruler I draw straight
lines to the opposite edge, making given angles with the edge from which they proceed.
The points from which each angular index proceeds may then be regarded as the zero
point of the said scale or scales, and the length of the arm of an angle may be set off
as described above.
*
By the term 'protractor-ruler,' I mean an elementary form of scale-ruler on which
the angles have not a common vertex.
I will now explain the accompanying drawings.
Figure 1 shows the set-square 45° marked with a scale of quarter inches extending
on both sides of the zero point.
Figure 2 shows a protector specially useful for the construction of polygons.
Figure 3 shows a protractor-ruler marked with a scale of inches on both long
edges, and has the angles 90°, 72°, 60°, 45°, and 30° proceeding from the inch
measuring points.
-
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 :-
The marking of set-squares, and all forms of protractors and scale-rulers with any
line or lines drawn from one or more of the given distances of a scale of linear
proportions inarked on the edge or edges of such instruments, or the marking of the
edge or edges of the said instruments with a scale of linear proportions the zero point
of which is coincident with the vertex of the angles marked on such instruments, by
means of which the length of one arm of an angle or angles, and also the direction
or length of the arm of the supplement to that angle, or supplements to those angles
may be set off by the same adjustment of the instrument as is required for the
construction or measurement of the angle itself, or angles themselves, in the manner
above described.
Dated this Twenty-eighth day of December 1888.