IMPROVEMENTS IN SHIPS' LOGS OR SPEED INDICATORS."
Year: 1876

page_text: LETTERS PATENT to William de Normanville, of No. 79, Bridge Road,
Hammersmith, for the Invention of "IMPROVEMENTS IN SHIPS' LOGS OR
SPEED INDICATORS."
PROVISIONAL SPECIFICATION left by the said William de Normanville at the
Office of the Commissioners of Patents on the 23rd June 1876.
WILLIAM DE NORMANVILLE, of No. 79, Bridge Road, Hammersmith. "IMPROVE-
MENTS IN SHIPS' LOGS OR SPEED INDICATORS."
This Invention has for its object improvements in ships' logs or speed indicators.
In order to indicate continuously the speed at which a ship passes through the
water I employ a screw or rotator, which is towed through the water by a cord or
wire which is connected by an universal joint with the first of a train of wheels in
a convenient position on board the ship. The train of wheels being thus put into
motion drives an axis to which weighted arms are jointed. The centrifugal force
tends to cause the arms to diverge from the axis, and this tendency is controlled by
springs, so that the divergence of the arms will vary with the speed of rotation of
the axis, which is dependent on the speed of the rotator, and that in turn on the
rate of the ship. The governor balls as they diverge give motion to an index
which shows the speed upon a dial.
A coiled spring prevents sudden fluctuations in the speed of the rotator being
transmitted to the index.
The apparatus above described may be employed to measure the velocity of
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William de Normanville in the Great Seal Patent Office on the
23rd December 1876.
WILLIAM DE NORMANVILLE, of No. 79, Bridge Road, Hammersmith.
MENTS IN SHIPS' LOGS OR SPEED INDICATORS."
" IMPROVE-
This Invention has for its object improvements in ships' logs or speed indicators.
I employ a screw or instrument towed through the water by a line or chain.
Rotary motion is transmitted through the tow line or chain to wheel work, and
[Price 6d.]

page_text: through a compensating arrangement, which prevents sudden changes in velocity,
an axis is driven. Balanced weighted arms are jointed to the axis, and under the
centrifugal force developed by rotation the arms tend to diverge from the axis,
towards which they are pressed by springs. As the arms diverge and converge
they move an index which shows the speed of the vessel upon a dial. The speed of
flow of water may also be measured by the apparatus.
In order that my said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a longitudinal section of the apparatus; Figure 2 is a transverse
section; Figure 3 is a plan with some of the parts removed; and Figure 4 repre-
sents separately the dial and index.
a, a, is the case of the instrument; it is constructed of cast iron, and is provided.
with a hinged lid a¹, immediately beneath which there is a plate of stout glass
secured in a water-tight manner. The bottom a² of the case can be removed by
taking out tap screws which hold it in its place. a³, a³, are lugs to receive clips,
by which the instrument is secured to the rail of the ship or vessel; a* is a stuffing
box in the side of the case to receive a spindle b carrying a universal joint b¹,
through which the connection with the rotator is made; a³ is a screw plug in the
bottom of the case, which when taken out leaves a hole admitting of the intro-
duction of a turnscrew to insert or remove the small screw pin b2, by which the
spindle b is held in a socket c¹ at the end of the axis c. The frame which carries
the axis c and the other working parts of the instrument is fixed to the bottom a²
of the case, so that the whole of the mechanism comes out with the bottom when the
bottom is removed; c² is a disc on the axis c; it bears against friction rollers d, d,
mounted on the frame so that the axis may revolve freely notwithstanding the
strain to which to which it is exposed in towing the rotator through the water;
c³ is a pinion on the axis c; it drives a wheel e¹ on an intermediate axis e, on which
again is a pinion e³ driving a wheel f¹ fixed on an axis f; f2 is another similar
wheel on the same axis, but able to turn upon it. It is fixed to the spring box g,
in which is a coiled spring having one end fixed to the axis and the other to the
interior of the spring box. This arrangement constitutes the regulating apparatus.
The spring being wound up by the action of the rotator is the maintaining power
driving the indicating instruments, to which it imparts a regular velocity free from
sudden changes. The wheel ƒ drives a pinion h¹ on an axis h, on which is also
In the middle of the
a spur wheel 2 gearing with a pinion on the main axis i.
axis a pin j is fixed which serves as an axis for the two arms k, k; they have
weights ¹,, at their ends, so arranged that each arm is balanced about its pivot
or axis j, so that the divergence of the arms is not affected by the pitching of the
vessel. ,, are links connecting the arms k with the collars m, m, which are
able to slide on the axis i, and the spiral springs n, n, tend constantly to press the
collars m outwards or away from the centre at j. When, however, the instrument
is in use the centrifugal action of the weighted arms compresses the springs more
or less, according to the speed of rotation. On one of the collars m there is a
disc m¹, against which a friction roller o¹ carried by the lever o bears. The lever o
has its fulcrum at o³, and carries at its upper end an are o³, attached to which is
one end of the fine chain p, which is also wound around a barrel q¹ on the axis q²
of the index q. 7 is a light spring surrounding the axis q, and attached to it at
one end, whilst the other end is fixed to the frame; it serves to hold the index back
against the action of the lever o to keep the chain p always tight and to hold the
roller o against the disc m¹. The dial is graduated to indicate the speed of the
ship in knots per hour.
The prime motor of this instrument is a small screw or rotator similar to that
used in other logs drawn after the vessel by a thin line some 150 feet in length.
The shaft of the rotator is about twelve inches long by about one inch in diameter.

page_text: It is made of such specific gravity that if left to itself it would slowly sink, but is
easily kept up by the line to which it is attached, drawing it through the water.
The action of the line working in opposition to the attraction of gravitation results
in its being kept in a horizontal position some eight feet below the surface of the
water. The rotary motion of the screw is conveyed by the line to the rest of the
mechanism.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I claim―
The construction of ships' logs or speed indicators wherein a screw or rotator is
caused through a flexible line to drive an axis provided with balanced weighted
lever arnis, the divergence and convergence of which controls the position of an index
on a dial which is so graduated that the speed of the ship or vessel may be read off
from it, substantially as described.
I also claim the employment of regulating apparatus substantially in the manner
described for the purpose of counteracting the effect upon the index of irregular
progress of the vessel.
I also claim the construction of ships' logs or speed indicators, substantially as
described.
In witness whereof, I, the said William de Normanville, have hereunto set
my hand and seal, this Twentieth day of December, in the year of our
Lord One thousand eight hundred and seventy-six.
WILLIAM DE NORMANVILLE. (L.S.)