IMPROVEMENTS IN THE MEANS AND APPARATUS FOR INDICATING THE SPEED OF SHIPS."
Year: 1875

page_text: LETTERS PATENT to Henry Edward Hargreaves, of Rio de Janeiro, in
the Empire of Brazil, but at present of No. 12, Fenchurch Street,
in the City of London, for the Invention of "IMPROVEMENTS IN THE
MEANS AND APPARATUS FOR INDICATING THE SPEED OF SHIPS."
PROVISIONAL SPECIFICATION left by the said Henry Edward
Hargreaves at the Office of the Commissioners of Patents, with
his Petition, on the 30th January 1875.
I, HENRY EDWARD HARGREAVES, of Rio de Janeiro, in the Empire
of Brazil, but at present of No. 12, Fenchurch Street, in the City of
London, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN THhe Means and Apparatus for Indicating the Speed OF SHIPS,"
to be as follows :-

page_text: rotation of the screw vanes of the log causes an electric current to be
passed at certain intervals of time (corresponding with a certain number
of revolutions of the vanes) along a conducting wire passing from the
log to a recording instrument on board the ship, so that the electric
current in actuating such recording instrument causes the speed of the
ship to be indicated continuously thereby.
According to my present improvements I arrange the screw vanes on
the end of a spindle projecting through a stuffing box, with india-rubber
packing at the one end of the casing of the log. On the end of the
spindle inside the casing is a worm in gear with a worm wheel, on the
face of which is a stud which at the completion of each revolution of
the wheel acts upon a projection on an insulated contact spring so as to
cause a pin on the latter to make contact with a second pin on another
insulated contact spring. Each of the contact springs is connected with
the end of an insulated conducting wire forming the core of the cable
by which the log is towed along. This cable is secured in a water-tight
manner in the end of the casing of the log by means of a collar fixed
thereon fitting inside a stuffing box, and secured therein by means of a
screw gland and india-rubber packing.
On board ship the conducting wires are connected to the poles of a
battery and to a recording instrument so that every time the electric
circuit is closed by the contact spring in the log as before described a
current is passed which acts upon the recording instrument. This latter
is of precisely the same construction as an ordinary Morse receiving
instrument used for telegraphic purposes, but the paper strip has
divisions marked thereon corresponding to minutes and hours, and the
clockwork of the instrument is so regulated that a division of the paper
corresponding to a minute will take a minute time to pass underneath
the marking instrument. As the latter is made to mark the paper strip
at the passing of every current, and as the intervals of time between the
passing of two currents represents a knot or a fraction of a knot traversed
by the log, it will be seen that the number of divisions occurring
between any two marks on the paper strip will indicate the time taken
by the ship in traversing a knot or portion of a knot, and thus à
permanent automatic record of the speed of the ship will be provided.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Edward Hargreaves in the Great Seal
Patent Office on the 16th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
EDWARD HARGREAVES, of Rio de Janeiro, in the Empire of Brazil, but
at present of No. 12, Fenchurch Street, in the City of London, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of January, in the
year of our Lord One thousand cight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cèssors, give and grant unto me, the said Henry Edward Hargreaves, Her
special license that I, the said Henry Edward Hargreaves, my executors,
administrators, and assigns, or such others as I, the said Henry Edward
Hargreaves, my 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 "Iм-
PROVEMENTS IN THE MEANS AND APPARATUS FOR INDICATING THE SPEED OF SHIPS,"
upon the condition` (amongst others) that I, the said Henry Edward
Hargreaves, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, 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.
"
NOW KNOW YE, that I, the said Henry Edward Hargreaves, do'
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, reference being had to the
accompanying Sheet of Drawings and to the figures and letters marked
thereon, that is to say :—
My Invention relates to that description of apparatus for indicating.

page_text: the speed of ships commonly known as "ships' logs," wherein the
rotation of the screw vanes of the log causes an electric current to be
passed at certain intervals of time (corresponding with a certain number
of revolutions of the vanes) along a conducting wire passing from the
log to a recording instrument on board the ship, so that the electric
current in actuating such recording instrument causes the speed of the
ship to be indicated continuously thereby.
According to my present improvements I arrange the screw vanes on
the end of a spindle projecting through a stuffing box, with india-rubber
packing at the one end of the casing of the log. On the end of the
spindle inside the casing is a worm in gear with a worm wheel, on the
face of which is a stud which at the completion of each revolution of
the wheel acts upon a projection on an insulated contact spring so as to
cause a pin on the latter to make contact with a second pin on another
insulated contact spring. Each of the contact springs is connected with
the end of an insulated conducting wire forming the core of the cable by
which the log is towed along. This cable is secured in a water-tight
manner in the end of the casing of the log by means of a collar fixed
thercon fitting-inside a stuffing box, and secured therein by means of a
screw gland and india-rubber packing.
.
On board ship the conducting wires are connected to the poles of a
battery and to a recording instrument, so that every time the electric
circuit is closed by the contact spring in the log as before described a
current is passed which acts upon the recording instrument. This latter
is of precisely the same construction as an ordinary Morse receiving
instrument used for telegraphic purposes, but the paper strip has
divisions marked thereon corresponding to minutes and hours, and the
clockwork of the instrument is so regulated that a division of the paper
corresponding to a minute will take a minute time to pass underneath
the marking instrument. As the latter is made to mark the paper strip
at the passing of every current, and as the intervals of time between the
passing of two currents represents a knot or a fraction of a knot traversed
by the log it will be seen that the number of divisions occurring between
any two marks on the paper strip will indicate the time taken by the
ship in traversing a knot or portion of a knot, and thus a permanent
automatic record of the speed of the ship will be provided.

page_text: LEDURIITION
IHE
'
The accompanying Drawing shews a sectional plan of my before-
described improved electric log. A is a brass casing, within which is a
spindle B passing through a tube D and stuffing box with gland V and
india-rubber packing W; on the outer end of the spindle is fixed the
propeller or screw vane C, by means of which, as the log is drawn
through the water, rotary motion is imparted to the spindle B. On the
inner end of the spindle is a worm in gear with a worm wheel E on a
spindle F, on the face of which wheel is a stud G, which at every
revolution of the wheel acts upon a cam or projection I on a contact
spring H so as to cause a pin J thereon to make contact with a pin K
on a second contact spring L. The two contact springs H and L are
fixed respectively to insulating blocks N and M, and to them are con-
nected the ends of insulated conducting wires O and P. These wires are
connected to the wires of an electric cable Q, Q, passing from the log to
the recording instrument on board ship. The cable has a collar R fixed
upon it inside a stuffing box, in which it is secured in a water-tight
The wires of
manner by the india-rubber packing S and screw gland T.
the cable Qbeing connected to the poles of a battery on
will be seen that every time the stud G causes the springs H and L to
make contact the electric circuit will be closed and a current will be
passed through the recording instrument operating as herein-before
described.
board ship it
The tube D of the propeller spindle is fixed to a brass diaphragm U,
which also carries a thrust bearing for the spindle.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I wish it to be understood that I
do not claim generally the use of ships' logs wherein the rotation of
screw vanes causes an electric current to be passed at intervals through
conducting wires connecting the log with a recording instrument on
board ship, but I claim,—
First. The combination in electric ships' logs of the screw vanes C,
spindle with worm B, worm wheel E, with stud G acting intermittently
on insulated contact springs H, L, connected to conducting wires O, P,
and electric cable Q, the whole arranged and operating as herein
described with reference to the accompanying Drawing.

page_text: Second. The use, in combination with an electric log, of a telegraphic
recording instrument whereby at each contact made by the action of the
log a mark is made on paper having time divisions on it for the purpose
of indicating and registering velocity, substantially as herein described.
In witness whereof, I, the said Henry Edward Hargreaves, have
hereunto set my hand and seal, this Twenty-ninth day of May,
in the year of our Lord One thousand eight hundred and seventy-
five.