Apparatus for Gauging the Internal Diameter of Cylinders and similar Objects and for Constructing Mechanical Diagrams of and in relation to the same.
Year: 1897

page_text: Date of Application, 15th Feb., 1897
Complete Specification Left, 6th Oct., 1897-Accepted, 6th Nov., 1897
PROVISIONAL SPECIFICATION.
Apparatus for Gauging the Internal Diameter of Cylinders and
similar Objects and for Constructing Mechanical Diagrams of
and in relation to the same.
I, THOMAS MESSENGER, of Paris House, Snargate Street Dover in the County of
Kent, Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to an instrument or apparatus for internally gauging and
testing the circularity of cylinders delineating the same
on paper, and is
designed more particularly for use with cylindrical furnaces.
Of late years the steam pressure in boilers has been greatly increased particu-
larly in marine boilers of the cylindrical type having cylindrical furnaces. Such
furnaces are liable to become distorted after use and it is necessary to frequently
gauge them to ascertain any deformation which may exist therein. This has
hitherto been usually accomplished by measuring them with a telescope gauge
diametrically in different directions, but this method is extremely inconvenient
and not nearly so exact as if these measurements were taken from the centre of
the cylinder-i.e.-radially.
The object of my invention is therefore to take these measurements radially
and to produce a diagram on a sheet of paper shewing the deformation, if any,
existing in a section of the cylinder as compared with a true circle. It consists
in arranging three telescopic legs radiating from a centre pin in such a manner
that they all move outwards or inwards simultaneously and equally: they are
placed at angles of 120° one with the other so that when the points of these three
telescope legs rest on the inner surface of the cylinder the centre pin will always
be in the centre of these three points, as hereafter explained.
I arrange a telescopic arm suitably provided with a roller at its outer end
pressed out by a spiral spring, which arnu works on the centre pin
and is moved round the cylinder; the roller will move inwards or out-
wards as it travels round following any irregularities in the cylinder, and if
a pencil be fixed to the telescope or sliding part of this arm and pressed against
a sheet of paper, it will describe thereon a diagram or representation of the form
of the cylinder and shew if it be a true circle or any departure therefrom; and
to make this more apparent to the eye, this arm can also be arranged to describe
a true circle from the same centre pin by means of the same pencil, this circle
being described in juxtaposition to the first mentioned diagram. From these
representations it can then be seen whether or not any deformation is to be
found in that portion of the cylinder tested.
I obtain this result preferably in the following manner: At the inner ends
of each telescope leg I fix a toothed rack and I cause a cog-wheel to gear with each
of these racks, the centres of the wheels being equidistant from the centre pin,
and I arrange a fourth wheel placed centrally between them which gears with
ach of the three, the result being the central wheel when turned in one direction

page_text: causes the three telescope legs to move outwards and if turned in the other direc-
tion causes the three legs to move inwards, all simultaneously and to an equal
extent.
In placing the instrument in a cylindrical furnace I prefer to place one of the
three telescope legs vertical resting on the bottom of the furnace, and on this
leg I place a spiral spring to take the entire weight of the instrument, which
enables it to be much more readily and quickly put in place; when the points
of these three telescope legs all touch the furnace, I fix them as follows:
On the centre wheel spindle or axis I fix a worm wheel with which gears a
worm working in a pivoted frame so that it can be instantly thrown in or out of
gear with the worm wheel and when the points of the three telescope legs touch the
inside of the furnace the worm then gearing with the worm wheel and being
turned in one direction, immediately presses the points of the three legs outwards
and locks them there thus firmly fixing the instrument in position, and the worm
being turned in the opposite direction as readily releases the instrument.
This manner of using a worm wheel and worm for producing and relieving
pressure will be found fully described in the Specification of my Letters Patent
No. 11049 of 17th September, 1885.
This worm wheel is on one side of the instrument and the central pin first
referred to is on the other side. On the central pin I suitably secure a small
drawing board on which I fix a piece of paper and from the foregoing description
it will be readily understood that if the telescope arm having a roller at its outer
end be moved round the furnace and the pencil attached to the outer portion of
this arm which moves inwards or outwards with the roller be brought into contact
with the paper, a diagram will be produced accurately shewing if the furnace be
true or deformed: and, although the pencil will revolve in quite a small circle
compared with the furnace yet the deformities if any will remain full size and
therefore be apparently magnified in proportion to the circle.
This enables these deformations to be much more easily read by the eye, and
they can be measured as if they were full size.
The framing to support the wheel spindles and the inner ends of the telescope
may be of any suitable form and material and the wheels engaging with the racks
may be replaced by suitable segments if desired.
Dated this 15th day of February 1897.
Apparatus for Gauging the Internal Diameter of Cylinders and
similar Objects and for Constructing Mechanical Diagrams of
and in relation to the same.
I, THOMAS MESSENGER, of Paris House, Snargate Street Dover in the County of
Kent, Engineer, 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:---
My invention relates to an instrument or apparatus for internally gauging and
testing the circularity of cylinders and delineating the same on paper, and is
designed more particularly for use with cylindrical furnaces.
Of late years the steam pressure in boilers has been greatly increased particularly

page_text: in marine boilers of the cylindrical type having cylindrical furnaces. Such
furnaces are liable to become distorted after use and it is necessaito frequently
gauge them to ascertain any deformation which may exist therein. This has
hitherto been usually accomplished by measuring them with a telescope gauge
diametrically in different directions, but this method is extremely inconvenient
and not nearly so exact as if these measurements were taken from the centre of
the cylinder i.e.-radially.
The object of my invention is therefore to take these measurements radially
and to produce a diagram on a sheet of paper shewing the deformation, if any,
existing in a section of a cylinder as compared with a true circle. It consists
in arranging three telescopic legs radiating from a centre pin in such a manner
that they all move outwards or inwards simultaneously and equally: They are
placed at angles of 120° one with the other so that when the points of these three
telescope legs rest on the inner surface of the cylinder the centre pin will always
be in the centre of these three points, as hereafter explained.
My invention will be more clearly understood by reference to the accompany-
ing drawings upon which,-
Figure 1 is a front elevation of my apparatus;
Figure 2 being a back elevation of the same, and
Figure 3 is a vertical section, the indicating arm being removed.
A, A1, A2, are the three telescopic legs; B is the centre pin; C, the telescopic
arm; C, sliding part of same; 1), roller on end of arm C; E, spiral spring between
parts C and C; F, pencil on sliding part C₁; G, one of three toothed racks:
H, H. H toothed wheels engaging racks G; I, central toothed wheel; K, spiral
spring on leg A; L, central worm wheel or segment; M, worm mounted n
pivoted frame N; O, drawing board; P, framing carrying wheel spindles.
In carrying out my invention, I arrange a telescopic indicating arm C, C¹,
provided at its outer end with a suitable roller D; the part C¹ is capable of sliding
in the part C, and is normally pressed outward by a spiral spring E. The arm C, Ci
is revoluble on the centre pin B of the apparatus in such a manner that the
roller D may move round in contact with the interior surface of the cylinder or
like object to be gauged. The roiler D will be moved inwards or outwards as it
travels round either by the pressure against it of the interior face of the cylinder,
or by the outward pressure of the spiral spring E upon the sliding part C₁ of the
telescopic arm, and will thus follow all irregularities existing in the cylinder.
A pencil F is fixed to the telescope or sliding part C of the indicating arm and
caused to press upon a sheet of paper on the drawing board through which the
centre pin B is passed, by which arrangement the pencil will be caused, when the
arm C, C is rotated within the cylinder, to describe upon the paper a diagram or
representation of the form of the cylinder shewing whether it be a true circle, or
any departure therefrom, and in the latter case indicating the locality and extent
of the deviation. To make the deviation more apparent to the eye, the indicating
arm and pencil can be arranged also to describe a true circle from the same centre
pin, this circle being described in juxtaposition to the first mentioned diagram.
From these representations it can then be seen whether any or what deformation
is to be found in the portion of the cylinder which has been tested.
I attain this result preferably in the following manner: At the inner end of
each telescope leg A, A1, A2, I fix a toothed rack G, G1 G2, and I cause a toothed
wheel H, H¹, H2, to gear respectively with each of the racks, the centres of the
three toothed wheels being equidistant from the centre pin B; and I arrange a
fourth wheel, I, placed centrally between the three so as to gear with each of them.
The result of this arrangement is that the central wheel I when turned in one
direction causes the three telescope legs A to move outwards from the centre,
and when turned in the other direction it causes the three legs to move inwards, or
towards the centre, all simultaneously and to an equal extent.
In placing the instrument in a cylindrical furnace for the purpose of gauging
the same,
I prefer to place one of the three telescope legs in a vertical position--

page_text: resting on the bottom of the furnace and on this leg, A, I place a spiral spring K
to take the entire weight of the instrument, which arrangement enables it to be
much more readily and quickly put in place; when the points at the outer ends
of the three telescope legs all touch the interior face of the furnace, I fix them
as follows:
On the centre wheel spindle or axis I secure a worm wheel or segment L with
which gears a worm M working in a pivoted frame N capable of turning on the
framing P, so that the worm can be instantly thrown in or out of gear with the
worm wheel L; and when the outer ends or points of the three telescope legs A
touch the inside of the furnace, the worm M being then in gear with the worm
wheel L and being turned in one direction, immediately projects the three legs
outwards pressing their points against the inside of the furnace and locks them
there, thus firmly fixing the instrument in position. When it is desired to remove
or to alter the position of the instrument, the worm is turned in the opposite
direction whereby it is readily unlocked and released.
This manner of using a worm wheel and worm for producing and. relieving
pressure will be found fully described in the Specification of my Letters Patent,
No. 11049 of 17th September 1885.
The worm wheel L is on one side of the instrument and the central pin B
first referred to is on the other side. On the central pin I suitably secure a small
drawing board on which is fixed a piece of paper, and from the foregoing descrip-
tion and accompanying illustrations it will be readily understood that if the teles-
cope arm C, C¹ carrying the roller D at its outer end be placed on the centre pin B
and moved round the furnace, while the pencil F, attached to the sliding part C
of the arm which moves inwards or outwards with the roller D, is brought into
contact with the paper, a diagram will be produced accurately shewing whether the
furnace be of true circular shape or deformed: and although the pencil will
revolve in quite a small circle compared with the dimensions of the furnace,
yet the deformities—if any-will be represented in full size and therefore be
apparently magnified in proportion to the circle.
In these conditions the deformations can be much more easily read by the eye
and they can be measured as if they were full size.
The framing Pl' which supports the wheel spindles and the inner ends of the
telescope legs may be of any suitable form and material, and the wheels, engaging
with the racks G may be replaced by suitable segments if desired.
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 apparatus for gauging the internal diameter of cylinders and similar
objects and recording the shape thereof in a diagram, comprising means for
locating the normally true centre of the cylinder, and an indicating arm C
adapted to travel around and follow the interior of the cylinder and to record the
shape of this latter as a diagram capable of being compared with a true circle
struck from the centre of the cylinder, substantially as described.
2. In apparatus for gauging the internal diameter and recording the shape of
cylinders and similar objects, the combination of telescopic legs A, A¹, "A²,
adapted to locate the true centre of the cylinder, with a telescopic arm C, C¹,
revolving within and recording the internal shape of the cylinder or other similar
object, substantially as and for the purposes described.
3. In apparatus for gauging the internal diameter and recording the shape of
cylinders and similar objects, the use of a spiral spring K on the telescopic leg A
resting vertically on the bottom of the cylinder or other similar object, for the
purposes and as set forth.
4. In apparatus for gauging the internal diameter and recording the shape of
cylinders and similar objects, the combination with a worm wheel L secured to

page_text: the centre wheel spindle, of a worm M working in a pivoted frame N, for the
purposes and substantially as described.
5. In apparatus for gauging the internal diameter and recording the shape of
cylinders and similar objects, a telescopic arm C, C, capable of a rotary and a
reciprocating movement and arranged to delineate the internal contour of the
cylinder or other similar object so that any deformations therein will be thereby
comparatively magnified when the resulting diagram is compared with a circle
struck from the centre of the cylinder as determined by the centre axis of the
telescopic legs A, A1, A2, as described.
6. Apparatus for gauging the internal diameter of cylinders and similar objects
and for constructing mechanical diagrams of, and in relation to the same, sub-
stantially as described and as illustrated on the accompanying drawings.
Dated this Sixth day of October 1897.
For the Applicant,
GEDGE & FEENY,
60 Queen Victoria Street, London, Chartered Patent Agents,