An Improved Device for Calculating Steam Indicator and other Diagrams.
Year: 1894

page_text: Date of Application, 23rd Aug., 1894-Accepted, 6th Oct.. 1894
COMPLETE SPECIFICATION.
An Improved Device for Calculating Steam Indicator and other
Diagrams.
Communicated by PERCY PRYCE-BROWN, of the Marine Club, Singapore.
I, GEORGE GILLSON PRYCE-BROWN of Lorne House, Barbourne, Worcester,
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 relates to an improved device to facilitate the working out or
calculating of steam indicator and similar diagrams, by the common method of
dividing the diagram into ten parts, by means of which a handy substitute for
squares, scales, &c., as commonly used, is provided.
For this purpose my improved device consists of a strip or bar of metal, or other
suitable material, in the form of an ordinary rule or scale, one end of which is
formed square for the purpose of drawing the lines at each end of the diagram at
right angles to the atmospheric line, and one side or edge of which is formed with
teeth or angular V shaped projections. The other edge, on both sides of the
device is marked with suitable measuring scales, and there is provided at each end
of the toothed edge, a point or projection for setting the device in correct position
upon the two end perpendicular lines. These two points are placed in contact
with the said lines and the device is slightly tilted so as to cause the points of
the said teeth to enter and mark the paper. Lines drawn through these points
or marks parallel with the end lines divide the diagram into equal parts, and
these lines, constituting the vertical lines are scaled off by the scales on the other
edge of the device in the usual manner.
In order to more clearly understand my said invention, and the manner of
carrying it out in practice,. I will describe the same with reference to the accom-
panying drawing, in which a represents my improved device placed incorrect
position on a diagram for marking the positions of the vertical lines b, b. Teeth or
points a', ten in number, are formed on one edge of the device, scales a² being
marked on the opposite edge. The dotted lines represent the indicator or other
diagram, and in order to calculate the pressures in the usual manner, I proceed as
follows.-
I place the end a³ which is made square with the edges, upon the atmospheric
line A. L. and draw the two perpendiculars B. C. and D. E. through the ends of
the diagram. The points or projections c, d of the divider a are then placed so as
to coincide with the lines B.C. and D. E. and as the points a¹ extend slightly
beyond the edges at c and d, impressions are made by the said points upon the card
or paper of the diagram by raising the other edge of the device and pressing the
points down. Each of these points marks the position of the ten division lines b
which lines are then drawn through these marks parallel to the lines B. C.
and D. E.
In order to correctly draw the said parallel lines, two rows of marks may be
made, one indicated at e below the other, the lines being then drawn through both
rows or sets of marks. The scales a² are then used for working out or calculating
the diagram in the usual manner.

page_text: Having now particularly described the nature of my said invention, and in what
manner the same is to be performed, I declare that what I claim is.-
(1.) The device for working out or calculating indicator and other diagrams,
consisting of the strip or bar a provided with points or teeth a', scales a³ and points
or projections c, d, substantially as described and for the purposes specified.
(2.) The improved device for working out or calculating indicator or other
diagrams, substantially as described and shown in the drawings.
Dated this 23rd day of August 1894.
GEO. H. RAYNER,
37, Chancery Lane, London, W.C., Agent for the Applicant.