IMPROVEMENTS IN ELECTRIC LOGS FOR MEASURING THE SPEED OF VESSLLS
Year: 1877

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, l'atent Agent, for the Invention of "IMPROVEMENTS IN
ELECTRIC LOGS FOR MEASURING THE SPEED OF VESSLLS" A communication
fiom abroad by John P Haines, of the City, County, and State of New York,
United States of Ameuca
Sealed the 17th July 1877, and dated the 31st January 1877
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 31st January 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent
"IMPROVEMENTS IN ELFCTRIC LOGS FOR MEASURING THE SPEED
OF VESSELS' A communication from abroad by John P Haines, of the City,
County, and State of New York, United States of America
This Invention relates to electic logs for measuring the speed of vessels, and it
consists mainly in the employment of a flexible diaphragm, as hereafter described,
to separate the chamber containing the termini of the electrical conducting wires
from the chamber containing the mechanism of the log for the purpose of excluding
the water from the former chambei
It also consists in the means of attaching the flexible diaphragm to a rod, by
which the mechanism of the log acts on the ends of the electric wies for the pui pose
of establishing the circuit
The log consists of a screw whose journals are mounted in a vane having a
chamber attached One journal of the screw extends and has a worm on it, which
engages with a worm wheel mounted in said chamber A pin on the face of said
wheel engages once at every revolution with a lever pivoted at one end, and having
a sping bearing down on its fiee end A 1od is connected to the lever, and passes
upward through an india-rubber diaphragm, which separates the chamber above
mentioned from another containing the termini of the electrical conducting wues
The two chambers are connected together by a screwjoint, in which the edges of the
diaphagin are securely clamped Clamping nuts or collars are also placed on the
above-mentioned rod at each side of the diaphragm to prevent the passage of water
through it The diaphragm thus serves to effectually exclude water from the con-
ducting wires, and allows free play of the 10d above mentioned. The cable by which
31

page_text: the log is towed is constructed with electrical conducting wires, whose termini are
contained in the chamber above referred to, and are bent down each at a right
angle and overlapping one another, but not touching, the arrangement being such
that a slight upward pressure of the rod would cause them to come into contact and
thus establish the circuit
The cable is securely fastened by passing through a stuffing box at the forward
end of the log, the stuffing box serving as well as the diaphragm to exclude water
from the chamber containing the termini of the conducting wires The operation
of the log is obvious, the conducting wires being connected with a battery, and an
electro-magnetic recording apparatus on board ship, and the log being towed in the
water by the eable, the screw revolves on its axis while the case containing the
transmitting mechanism is prevented from turning by the vane The velocity of
the screw is proportionate to the speed of the vessel, a given number of revolutions
representing a certain distance The worm tuning the worm wheel causes the pin
to raise the level, bringing the rod against the one terminal wie, and pressing it
against the other, completing the cucuit and registering a unit of distance in the
apparatus on board the vessel
When the pin leaves the lever the latter is caused
by its spring to regain its noimal position, allowing the wires to separate, breaking
the electrical connection
Any of the ordinary forms of electrical recording apparatus may be used in con-
nection with the log
A single conducting wire may be used in the cable, and the current allowed to
return by the water if desired
The log may be used to indicate the velocity of streams of currents of water by
connecting the cable to a fixed object, so that the moving water may act on the
screw
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 24th
July 1877
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent
"IMPROVEMENTS IN ELECTRIC LOGS FOR MEASURING THE SPELD
OF VESSELS" A communication from abroad by John P Haines, of the City,
County, and State of New York, United States of America
This Invention relates to electric logs for measuring the speed of vessels, and
consists in the improvement thereof, as herein-after shown and described
Figure 1 is a side elevation of a log, Figure 2 is a front elevation in part in
section, Figure 3 is a front elevation enture, Figure 4 is a section on line x, x,
Figure 2, Figure 5 is a detail view of the termini of the conducting wires
A is a screw consisting of a hollow cylinder of metal, having the journals a, b,
and the spual wings c
Attached to a vane B are boxes for the journals a, b, and
at the front end of the vane a chamber & is attached, in which the worm wheel e
and lever fare placed The Journal a extends beyond its box, and has a screw g
formed on it, which engages with the wheel e his a pin projecting from the side
of the wheel e, that engages with the lever fonce at every revolution The lever f
is pivoted at 2, and has a spring, bearing down on its fice end. A rod is con-
nected to the level fat l, and passes upward through an india-rubber diaphragm m,
which separates the chamber & from the chamber C that contains the termini of the
electrical conducting wies o, o' The two chambers are connected together by a
screw joint, in which the edges of the diaphragm are securely clamped. Clamping
nuts or collars n are also placed on rod at each side of the diaphragm to prevent
the passage of water through it. The cable 1), by which the log is towed, contains
the electrical conducting wires o, o¹, whose termini are in chamber C, as above
mentioned. The end of the wire o is bent over at a right angle, and the end of the

page_text: wire o is bent so as to overlap it, but does not touch it, the arrangement being
such that a slight forward pressure of the rod k would cause them to come into
contact, and thus establish the cucuit.
The cable D is securely fastened by passing through a stuffing box p at the
forward end of the apparatus The stuffing box also excludes water from the
chamber C The operation of the log is obvious, the conducting wires o, o¹, being
connected with a battery and an electro-magnetic recording apparatus on board
ship, and the log being towed in the water by the cable D the screw A revolves on
its axis, while the case containing the transmitting mechanism is prevented from
tuning by the vane B The velocity of the screw is proportionate to the speed of
the vessel, a given number of revolutions representing a certain distance The
scrow g, by turning the wheel e, causes the pin h to raise the lever f, binging the
rod k against the terminal wine o', which is thereby pressed against the wire o, thus
completing the cucuit, and registering a unit of distance in the apparatus on board
the vessel When the sping leaves the lever the spring causes the lever to
iegain its norinal position, allowing the wies o¹, o, to separate, breaking the electrical
connection The diaphragm m and stufhing box p effectually exclude the water
from the chamber C
Any of the ordinary forms of electrical recording apparatus may be used in con-
nection with the log
A single conducting wire may be used in the cable, and the current allowed to
return by the water if desired
The log may be used to indicate the velocity of streams of currents of water
by connecting the cable with a fixed object, so that the moving water may act on
the screw
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the herein-
before in part recited Letters Patent is,―
1st Constructing the log case containing chambers C and d in two parts united
by a sciew Joint with a flexible diaphragm clamped between, substantially as shown
and described
2nd. In an electric log the employment of a flexible diaphragm clamped in the
joint which unites the two parts of the log case, to separate the chamber containing
the terınını of the electrical wires from the chamber containing the mechanism, and
keep the water out of the former chamber, substantially as shown and described
31d The combination of the flexible diaphragm m, 1od, electrical wires o,
chamber C, substantially as shown and described
o¹, and
4th The attachment of the diaphragm m to the shaft k by means of clasping discs
or nuts n, as described, thereby allowing the free play of the shaft k and diaphragm
m, but preventing the passage of water
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twentieth day of July, in the year of our Loid
One thousand eight hundred and seventy-seven.