IMPROVE- MENTS IN APPARATUS FOR USE AS A FOG ALARUM, AND TO GIVE AUDIBLE SIGNALS
Year: 1876

page_text: LETTERS PATENT to William Brookes, of 62, Chancery Lane, in the County of
Middlesex, Patent and Registration Agent, for the Invention of "IMPROVE-
MENTS IN APPARATUS FOR USE AS A FOG ALARUM, AND TO GIVE AUDIBLE
SIGNALS." A communication from abroad by Horace Ross Sewell, of the
City, County, and Province of Quebec, in the Dominion of Canada, and George
Sweanor, of Sherbrooke, in the County of Sherbrooke, in the Province of
Quebec aforesaid.
Sealed the 28th October 1876, and dated the 19th May 1876.
PROVISIONAL SPECIFICATION left by the said William Brookes at the Office
of the Commissioners of Patents on the 19th May 1876.
WILLIAM BROOKES, of 62, Chancery Lane, in the County of Middlesex, Patent
and Registration Agent. "IMPROVEMENTS IN APPARATUS FOR USE AS A FOG
ALARUM, AND TO GIVE AUDIBLE SIGNALS." A communication from abroad by Horace
Ross Sewell, of the City, County, and Province of Quebec, in the Doniinion of
Canada, and George Sweanor, of Sherbrooke, in the County of Sherbrooke, in the
Province of Quebec aforesaid.
The object of the Invention is to enable an alarum to be sounded intermittently.
For this purpose a cylinder is operated to cause its rotation when required by
micans of a coiled spring or weight and band. When a spring is used the unwinding
of the axis is prevented by a ratchet and stop. To this cylinder is applied a
toothed wheel, the teeth of which gear with the teeth of a pinion, on the shaft of
which is applied a friction wheel with a surface composed of different diameters.
This surface is acted upon by an elastic friction brake, by which an alternately
fast and slow motion may be given to the operating gear. On the shaft of this
pinion is also applied an eccentric or cam course to receive the bowl or end of an
arm, from an axis on which is also applied another arm, the end of which by
suitable connection operates the piston of an air cylinder. To this air cylinder
is applied a reed and horn whistle or other device for sounding the desired alarum.
By the variable motion referred to a fast motion is obtained to the piston for
compressing the air in the production of sound. If desired two sounding means
may be applied, one to give a shrill sound, as when a vessel is on its port tack,
the other a deeper note when on the starboard tack, or as may be desired to
indicate the direction of sailing, as in a fog, or for other use.

page_text: Figure 1 is a side elevation of my fog alarum. Figure 2 is a plan of the same.
A is the frame of the machine, having a platform on which the air cylinder B is
mounted and in which the driving mechanism has its. bearings. R is the driving
drum, which is operated either by an internal coiled spring C or by a rope and
weights from its periphery, as may be desirable. D is a toothed wheel secured to
the end of the drum R, taking into the teeth of a pinion E on the shaft H. S is a
ratchet wheel keyed on the shaft U, passing through the drum R, engaging with
a pawl V attached to the frame A to prevent rotation of the shaft during the
expansion of the coiled spring. G is a friction wheel keyed on the shaft H of
the pinion E, and said wheel has a periphery of eccentric curves, and in its side an
eccentric groove I receiving a friction roller having a wrist pin connection with
the end of the arm J keyed on the rock shaft K. Journaled in the main frame A.
centrally is keyed to the rock shaft Ka lever M suitably bent under the drum R,
and to the opposite end of the lever M is hinged the piston rod N having pivotal
connection with the piston O, operating in the air cylinder B, to the head of which
is fixed a horn T provided with a reed W for trumpeting an alarm, or instead of
such horn a whistle or other device may be employed for producing sound by a
blast from the air cylinder passing through the same. P is a brake arm fixed to
the frame A, having a spring brake adjustable by a set screw Q to the periphery of
the wheel G for partially arresting its motion by its eccentrical projections,
increasing the frictional contact therewith to give a slow motion to the operating
gear when the piston is descending. After the eccentrical projections have passed
the brake the periphery of the wheel being more concentrical the friction becomes
lessened, and producing a fast motion to operate the piston when ascending, which

page_text: fast motion compresses the air in the cylinder, and by means thereof a sound is
produced by the air rushing through the trumpet or whistle.
Having thus described the nature of the said Invention as communicated to me,
I would have it understood that what I claim and wish to secure by my Letters
Patent is-
First. In fog alarms an air cylinder B having a piston O and piston rod N
operated by winding mechanism, giving a fast and a slow motion to the piston
for intermittently sounding a trumpet or whistle connected to the cylinder, as
set forth.
Second. The combination with a winding drum and wheels of the friction
wheel G, having an irregular eccentrical periphery, and laterally a can grove I, the
arm J, rock shaft K, lever M, piston rod N, and piston O, operating in an air
chamber B for sounding a trumpet or whistle attached thereto automatically and at
intervals, the whole operating as set forth.
In witness whereof, I, the said William Brookes, have hereunto set my hand
and seal, this Fifteenth day of November, in the year of our Lord One
thousand eight hundred and seventy-six.
WILLIAM BROOKES. (L.S.)