An Improved Apparatus for Reading Slide and Piston Valves.
Year: 1894

page_text: Date of Application, 19th Oct., 1894
Complete Specification Left, 29th May, 1895-Accepted, 12th Oct., 1895
.PROVISIONAL SPECIFICATION.
An Improved Apparatus for Reading Slide and Piston Valves.
of Engines.
I, NEWNHAM BROWNE, of 73, Cheapside, in the City of London, Chartered
Patent Agent, do hereby declare the nature of this invention which has been com-
municated to ine by Herbert Joseph Head, of 8, Old Dockyard Road, Mazagon,
Bombay, in the Empire of India, Engineer and Draughtsman, to be as follows:-
My invention consists in an improved apparatus represented in the accompanying
sheet of drawings, the construction and design of which apparatus will be readily
understood from the following description of the manner of using it.
Place the pointer exactly on the vertical line, spread the legs to the required
angle, being the angle of eccentric, mark the edge "Ast" on the suitable travel
circle, then by turning the pointer around till the edge "Ahd" reaches the mark
made and further past according to the amount of lead required (each lead space
being equal to of an inch) the pointer then indicates the cut off in decimal parts,
according to the length of connecting-rod on circles A, B or C, which are marked
off with lengths of connecting-rod 2, 21, and 24 times the length of stroke of engine
respectively.
EXHAUST MOVEMENTS :
Put the edge "Ah" on to the mark made and moving the sliding piece in or
out according to cover or otherwise being required, the opening and closing of
exhaust is read from edges <<
open" and "close" on the outer circles A, B or C.
For giving exhaust cover move the sliding piece in the direction indicated by the
arrow point.
The divisions on the sliding piece represent of an inch each.
The same operations are gone through on the other side for the up stroke, the
angle of the legs being kept the same and more lead being given as usual on the
up stroke.
Up to 8" travel of valve all laps and leads are to be taken as full size, but for
greater travels can be taken as half size on smaller circles. Travels of odd size
can be shown by dividing space between any two circles or by drawing a pencil
circle.
It is understood that other circles for other proportions of lengths of connecting
rods may be added without departing from the essence of the invention.
The machine is simple in construction and easy to understand also as it is shewn
it is readily adaptable to the different sizes and valves of engines by using it as
half size for longer travels, and by reversing the pointer for internal cut off
piston valves.

page_text: Provision is made for taking the length of connecting rod into consideration by
having different cireless marked off with different lengths of rods into the same
number of parts, and by having a sliding extension point on to pointer.
The manner of using the exhaust sliding piece as well as the manner of shewing
the lead is novel and convenient.
Dated the 17th dari of Optolide 1894
An Improved Apparatus for. Reading Slide and Piston Valves
of Engines.
I, NEWNHAM BROWNE,. of 73 Cheapside,.in. the City of London, Chartered
Patent Agent, do hereby declare the nature of this invention, and in what
manner the same is to be performed which has, been communicated.: to me by
Herbert. Joseph Head, of 8 Old Dockyard Road, Mazagon, Boinbay, in the.
Empire. of India,. Engineer, and Draughtsman, to be as follows:-
1
This invention consists in an improved apparatus represented in the accompanying
sheets of drawings in which
Fig. 1 represents the complete instrument.
Fig. 2 the various parts separately; and details and.
Fig. 3 is a diagram showing the genesis of the.scales in the outer circles.
A is the base piece. B the dial... C is a central pivot secured, by a nut D.
E and Fare a pair of legs jointed together. with a foot rule. joint G preferably
riveted; and through the centre of which trivet a small hole is bored to fit the
pivot C.
The arms e and fare respectively parts of the arms E and F, and are jointed to
the links H and I, the other ends iof which links fit on to the bolt J, which slides
in, and may be clamped at any part of the slot k in the pointer K.
The free end of the pointer K is constructed as shown more clearly in Fig: 12 (in
which it is also shown in section at k¹) to receive the sliding extension piece L
whereby the point may be adjusted to indicate the divisions on either of the circles
such as a, b, or c described to suit the proportion of length of the connecting rod to
the stroke, those shown in the drawings.being arranged for a connecting rod 2, 21
or 2 times the length of the stroke.and the divisions on the pointer K indicated by
the letters, a, b and c are marked 2, 24 and 2 respectively and serve to facilitate
the, setting of the sliding extension piece I..
The exhaust sliding piece M is carried, on the arm F on which it slides, the
part m (shown in transverse section at m¹) working in the undercut groove n.
The arm F is shown in section at F¹, and the, arm. E at E. A mark on the
slide m indicates the divisions on a scale, on the arm Fand when this mark is at
zero. the line of the edge of the exhaust sliding piece M passes through the centre
of the instrument, and from this zero position the slide moves in or out to allow for
cover or otherwise...
The edge p. of the arm E I mark "Ast Edge" and, the edge 7 of the arm F
I markAh Edge."
" and the
The edge of the exhaust sliding piece M, I mark "Close Edge
edges of the same piece I mark "Open Edge" a section of the piece M through
the edges is shown at s¹.
The dial B is marked, by way of example, with eight circles called travel
circles, from one to eight inches diameter, corresponding with the travel of the
slide valve, and then beyond these, three other circles forming three concentric
annular spaces marked a, b, and c with divisions from which is read the parts of
the stroke.

page_text: These divisions are obtained as follows:
Reference being had to Fig. 3 which is a diagram on a reduced scale.
Draw a circle T of the size of that on the face of the instrument. Draw a
vertical diámeter t, T, and produce it beyond T to U:
If now the circle is to be divided for use with a connecting rod 2 times the
length of the stroke, make T, U equal to 24 times the diameter of the circle.
Make UV equal to the t. T.
Divide UV into 10 parts and subdivide each of these parts into 10-and
beginning at U number them from 1 to 100..
Then with the radius U T from division 1 on the line U T draw an are cutting
the circle T at 1 and 1. With the Sam radius from the division 2 draw an arc
cutting the circle at 2 and 2, and with the same radius repeat the operation
from each one of the divisions on the line UT completing the division of the
circle which is then the circle č.
a
The sainė process is gone through for each of the circles 6 and a, using
radius of 2 and 2 diameters respectively (instead of 2) and in the same
manner circles may be divided for any other proportions of connecting rod to
stroke.
The lead spaces are shown as horizontal lines th of an inch apart.
For internal cut off piston valves the pointer may be made to reverse or may be
taken as being diametrically opposite, a centre line being marked through the
pointer for that purpose.
It is essential that the two legs E and F open out equally from the centre, and
that when closed the centre line of the pointer and edges of legs form a straight
line.
The links HI secure this symmetrical arrangement of the legs E F in relation to
the pointer K and serve to keep the legs at any désired position, being secured by
the bolt J working in the slot of the pointer K.
The method of using the apparatis will be understood from the following
description.
TO FIND THE CUT OFF.
Place the pointer exactly ou the vertical line; spread the legs to the required
abgle, being the angle of eccentric, mark on the face of the dial the point where
the edge p (marked Ast Edge) cuts the travel circle corresponding with the travel in
inches of the slide valve, then by turning the pointer around till the edge "Ahd"
reaches the mark just made aud further past according to the amount of lead
required (each lead space being taken equal to th of an inch) the pointer then
indicates on circle a, or c the cut off of steam in decimal parts of the stroke. of
engine; the reading being taken from that circle which corresponds with the
proportionate length of the connecting rod; these circles being; in the annexed
drawings, respectively arranged for lengths of connecting rod 2, 24 and 2 times
the length of the stroke of the engine.
TO FIND THE LAP.
With the instrument as now set-From the point of intersection of the appro-

page_text: "
from the edges "open" and "close on one of the outer circles ab or c, according
to the length of the connecting rod. For giving exhaust cover move the sliding
piece in the direction indicated by the arrow point on the slide m.
The divisions on the arm F for regulating the sliding piece are 16th of an inch.
each
The same operations are gone through on the other side for the up stroke, the
angle of the legs being kept the same, and more lead being given as usual on the
up stroke.
Up to 8 inch travel of valve all laps and leads, are to be taken as full size, but
for greater travels can be taken at half size on smaller circles. Travels of odd
sizes can be shown by dividing space between any two circles or by drawing a pencil
circle.
It is understood that other circles for other proportions of lengths of connecting
rods may be added without departing from the essence of the invention..
The following examples show the actual practice to be followed in using the
apparatus.
PROBLEM 1.
In designing an engine whose stroke is to be 48 inches, the connecting rod
being 2 tin es the length of the stroke, the travel of the valve 4 inches, lead on
top th inch and on bottom inch, the angle of the eccentric 57 degrees, and the
valve having inch internal cover on the bottom. i.e. for up stroke.
It is required to find at what part of the stroke the steam is to be cut off, also
the opening and closing of the exhaust in the cylinder.
1st. As the rod is 24 times the stroke, place the pointer on circle c.
2nd. Spread the legs E, F, to the given angle and clamp them by the screw J.
3rd. The pointer being vertical, mark on the face of the dial where the edge p
(Ast Edge) cuts the 4 inch circle, the pointer is then turned 1ound till the edge q
(Ah Edge) comes on to the mark, then for lead turn further one lead space, and
the pointer will indicate on circle c the cut off 40%
=
40
100
of 48 ins.
4th. The edge Ahd is now put back one space on to the mark, and the edge s
of the exhaust sliding piece M, marked "open edge" cuts the scale on circle c at 81
that is to say 100 of 48 ins. and edge marked "close edge" cuts the scale at 74
that is to say 7 of 48 ins.
Having thus finished the reading for the down stroke we proceed to read for
the return stroke, for which purpose the pointer is now turned to the bottom the.
legs remaining at the same angle, and the same process is gone through allowing
two spaces for lead, the cut off shows at 34.
As there is inch cover on the exhaust, on the bottom, move the slide in
direction of "cover," equal to that amount, when reading the up stroke.
PROBLEM No. 2.
Find the angle of eccentric, the lap on lead, top and bottom, in a cylinder
required to cut off at stroke, the connecting rod being twice the length of stroke,
the top lead not to be more than 1 inch.
1st. With a pair of dividers measure the distance from 0 to 25 on the 8 inch
circle, open the legs to this size on the same circle, this is the angle of eccentric
without any lead which must be allowed for to get the correct angle by slightly
closing the legs, the angle being correct when the cut off is as required; then
proceed as in (3rd) Problem 1.
2nd. When at the cut off position the distance from the edge Ah" on the travel
circle upwards to the horizontal line is the lap on top, the lead being the amount
previously advanced 1 inch.
3rd. Now by turning the pointer to the bottom the angle of the legs being the
same, mark the edge Ast on the circle, then by turning the pointer to the 25°/

page_text: mark, the number of spaces between the Alª edge and the mark is the amount or
lead in eighths of inch required on the bottom, to get the same cut off as on the
down stroke, the lap being measured as for the top, only downwards.
"
Throughout it assumed that a vertical engine is in question and in such case
In a horizontal
engine the "out" stroke would be the down stroke, and the "in" stroke the up-
stroke.
top" refers to the down stroke and "bottom" to the up stroke.
The instrument is a mechanical adaptation of the geometrical method, so what
can be done in an hour with that method (which is somewhat intricate) is done in
a few minutes by the aid of this instrument.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed as communicated to me by
ny foreign correspondent 1 declare that what I claim is :-
1. The improved apparatus for reading slide and piston valves of engines
substantially as described.
2. The apparatus herein before described and represented in the drawings
comprising a dial having travel circles, and circles of scales for making the parts of
stroke, a central bolt C, arms E and F and pointer K, exhaust piece M sliding
described.
on arm F, substantially as and for the purpose
Dated the 29th day of May 1895.
NEWNHAM BROWN,
Agent for the Applicant.