An Improved Drawing and Measuring Appliance.
Year: 1894

page_text: Date of Application, 14th Nov., 1894-Accepted, 22nd Dec., 1894
COMPLETE SPECIFICATION.
An Improved Drawing and Measuring Appliance.
We, THOMAS FRITH JOF JOHANSON, Eugineer, of 82 Millerbank Street,
Springburn, and HENRY RANKINE KERR, Engineer of 4 Wellfield Street,
Springburn, both in the City and County of Glasgow, do hereby declare the nature
of our invention, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement in
writing, that is to say :-
This invention has reference to and comprises a portable clinometer appliance
in which are combined a protractor, a swivelling ruler or scale, and a plumb level,
and which will perform the duties of an adjustable set square or T square and be
very convenient for expeditiously indicating angles and drawing parallel lines
therewith, and be useful for surveyors and engineers, and especially for workmen
drawing accurate angled lines on metal plate or wood work in the workshops.
And in order that our said invention and the manner in which it may be carried
into practice may be properly understood we have hereunto appended an explanatory
drawing representing a plan view of our improved appliance.
Referring to the drawing:-The improvements consist in forming a protractor
head A preferably of a rectangular shape as shown, and having the usual radial
lines a drawn from its base centre and the semicircular lines a', and the figures
indicating the degrees. By our improvements a rule B is mounted by a pin A*
formed on the plate A and an adjustable thumb screw B' at the base centre of the
protractor plate A from where the radial lines a are drawn, and the one end B' of
this rule B extends to the edge where the degrees are marked on protractor, and
is tapered to a point, so as to have its centre in line with the radial lines of
protractor. The other end of rule extends any desired distance out beyond the
base of protractor as say six inches, and may be marked with inch or other divided
scales. When this protractor apparatus is to be used the pointer end B2 of rule is
set opposite the radial line angle of which the parallel line is to be drawn, such
as indicated in the dotted position, and the line is drawn by a pencil or pen taken
along the edge of ruler B on the surface desired, and the ruler is simply swivelled
to the next angle of which the line is desired to be drawn, and may be fixed in any
desired position by a pinching screw or otherwise.
This apparatus may be used as a set drawing square by setting the rule B to the
desired angle and sliding the edge A' of protractor plate along a parallel surface
or it may be used as a T square the protractor plate A forming the head. While
it can be used along with a plumb line C by fixing the end of the line at the
end B³ of the ruler B and letting the metal weight C¹ drop to form and register
any angle, which can be then fixed by turning the pointer B2 to this angle and
fixing it by the thumb screw B'. Thus if the edge A¹ of the protractor plate A,
is placed on the top of a horizontal surface or plane, if the plumb line comes
opposite a centre line formed in the rule B and the metal weight C' comes opposite
the cavity b, it will indicate that the surface is at a true horizontal level, or if it
does not the rule B can be adjusted until this takes place and the angle will be
indicated by pointer B2 on protractor scale. While if the edges A² or A³ of
protractor plate A are placed against a vertical surface or plane the cord C will
act as a plumb line and the level or angle be indicated in a similar manner.

page_text: Having now particularly described and ascertained the nature of our said inveu-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
An appliance constructed and arranged substantially as and for the purposes
herein described.
1
201
T
2004