IMPROVEMENTS IN DIRECT-ACTING STEAM ENGINE INDICATORS
Year: 1869

page_text: LETTERS PATENT to John Addy Hopkinson and Joseph Hopkinson,
junior, both of Huddersfield, in the County of York, Engineers,
for the Invention of "IMPROVEMENTS IN DIRECT-ACTING STEAM ENGINE
INDICATORS."
Sealed the 21st September 1869, and dated the 31st March 1869.
PROVISIONAL SPECIFICATION left by the said John Addy Hopkinson
and Joseph Hopkinson at the Office of the Commissioners of
Patents, with their Petition, on the 31st March 1869.
We, JOHN ADDY HOPKINSON and JOSEPH HOPKINSON, junior, both of
Huddersfield, in the County of York, Engineers, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN DIRECT-ACTING STEAM
ENGINE INDICATORS," to be as follows:-
Our Invention consists in making a direct-acting steam engine
indicator with a detached revolving barrel, and dispensing with the
slides in which the pencil holder usually works. For this purpose an
arm or pencil holder is fixed upon the top of the ordinary piston rod
of the indicator, which arm turns on a swivel centre, and at a lower

page_text: point there is fixed a swivel arm which is so formed as to admit of a
drop guiding rod passing through it, so that by turning the swivel arm
the pencil can be brought upon the paper which is usually fixed on the
revolving barrel, thereby facilitating the taking of diagrams. This
arrangement not only dispenses with the ordinary slides, but also with
joints and prevents unnecessary friction, together with the liability to
derangement, and allows other improvements to be carried out.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Addy Hopkinson and Joseph Hopkinson
in the Great Seal Patent Office on the 29th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
ADDY HOPKINSON and JOSEPH HOPKINSON, junior, both of Huddersfield,
in the County of York, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of March, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-second
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said John Addy Hopkinson and Joseph Hopkin-
son, Her special licence that we, the said John Addy Hopkinson
and Joseph Hopkinson, our executors, administrators, and assigns,
or such others as we, the said John Addy Hopkinson and Joseph
Hopkinson, our executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN DIRECT-ACTING STEAM ENGINE INDICATORS," upon the
condition (amongst others) that we, the said John Addy Hopkinson
and Joseph Hopkinson, our executors or administrators, by an instru-
ment in writing under our, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.

page_text: NOW KNOW YE, that we, the said John Addy Hopkinson and
Joseph Hopkinson, do hereby declare the nature of our said Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, reference
being had to the Drawing hereunto annexed, and to the letters and
figures marked thereon (that is to say) :-
:-
Our Invention of " Improvements in Direct-acting Steam Engine
Indicators" consists in making a direct-acting steam engine indicator
with a detached revolving barrel, and dispensing with the slides in which
the pencil holder usually works. For this purpose an arm or pencil
holder is fixed upon the top of the ordinary piston rod of the indicator,
which arm turns on a swivel centre, and at a lower point there is fixed
a swivel guiding arm which is so formed as to admit of a drop guiding
rod passing through it, so that by turning the swivel arm the pencil can
be brought upon the paper which is usually fixed on the revolving barrel,
thereby facilitating the taking of diagrams. This arrangement not only
dispenses with the ordinary slides, but also with joints and prevents
unnecessary friction, together with the liability to derangement, and
allows other improvements to be carried out.
Having thus stated the nature of the said Invention, we will proceed
to describe more particularly in what manner the same is to be per-
formed, by reference to the accompanying Drawing, in which our
improved indicator is represented.
In this Drawing E is the pencil at the end of the swivel arm C, a part
of which is turned down to a collar and fits on the piston rod G, being
suitably held by a nut on the upper side. D is a horizontal arm working
from the cap cover of the barrel A and acted upon as required by the
hand of the attendant. In this arm there is formed a suitable hole,
through which the drop guiding rod F slides. It will be seen from this
connection that any upward or downward motion of the piston rod will
be imparted to the swivel arm C, and that by directing this motion
through the medium of the arm D upon the barrel B the pencil may be
applied or withdrawn with the utmost facility, and indications may be
registered as required.
The internal arrangement of piston and spring is similar to the usual
description of indicator, and does not therefore need to be described.
We would remark that the novelty in this instrument consists in the
lightness of the arm, and the important feature of having only one joint,

page_text: thereby securing increased steadiness and firmness at the point of the
pencil.
Having thus described the nature of the said Invention, and in what
manner the same is to be performed, we hereby declare that what we
claim as of our Invention is, the adaptation and application of the
improved arrangement of swivel arm pencil holder, herein-before described,
to direct-acting steam engine indicators.
In witness whereof, we, the said John Addy Hopkinson and Joseph
Hopkinson, have hereunto set our hands and seals, the Twenty-
eighth day of September, in the year of our Lord One thousand
eight hundred and sixty-nine.
JOHN JAMES ROEBUCK,
St. Peter's Street,
Huddersfield,
Book-keeper.
JOHN ADDY HOPKINSON.
(L.S.)
JOSEPH HOPKINSON, JUNIOR. (L.S.)

page_text: LONDON: Printed by GEORGE EDWARD EYRE and WILLIAM SPOTTISWOODE,
Printers to the Queen's most Excellent Majesty. 1869..