IMPROVEMENTS IN FOG-HORNS AND SIMILAR INSTRUMENTS FOR PRODUCING POWERFUL SONOROUS EFFECTS, PART OF SUCH IMPROVEMENTS BEING APPLICABLE. FOR OTHER PURPOSES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Francis George Fleury and Thomas
Joseph Noakes at the Office of the Commissioner's of Patents on the 4th July
1883.
FRANCIS GEORGE FLEURY, of 4 Bell's Buildings, Salisbury Square, in the
County of Middlesex, Mechanical Engineer, and THOMAS JOSEPH NOAKES, of 195
and 196 Brick Lane, Spitalfields, in the County of Middlesex, Manufacturer,
"IMPROVEMENTS IN FOG-HORNS AND SIMILAR INSTRUMENTS FOR PRODUCING
POWERFUL SONOROUS EFFECTS, PART OF SUCH IMPROVEMENTS BEING APPLICABLE.
FOR OTHER PURPOSES"
i
Our invention relates to Fog-horns and similar instruments constructed on the
"reed" or .vibratory tongue principle. It has hitherto been a common practise to
employ brass for the tongue of such instruments in order to avoid corrosion.
Tongues formed of such a metal, however, when subjected to the severe vibrations
they have to perform, rapidly deteriorate in character and become unserviceable.
In order to overcome this defect we employ steel as a material for the tongues;
and having carefully tempered the same we electroplate them with nickel, silver or
other comparatively non-corroding metal.
Our invention further relates to means for controlling the steam or other aeriform
fluid under pressure for producing the blast. For this purpose we employ a
cylindrical or other chamber provided with inlet and outlet passages. The same is
by preference placed horizontally and the passages referred to arranged in the
bottom and top sides thereof respectively. The cylinder is fitted with a plunger
and the latter is connected through one end of the said cylinder with a hand lever,
by means of which a reciprocative motion may be imparted. The plunger may be
packed circumferentially with spring rings, but we prefer to pack it on each side
with a strip of asbestos or other suitable soft packing arranged in longitudinal
recesses in the interior of the cylinder. This latter method of construction is
applicable to valves generally. The plunger is further provided with a transverse.
passage so arranged that in one position of the plunger there is a free communication
between the cylinder ports, whilst in another position of the plunger communication
is entirely shut off. By means of this apparatus we are enabled to produce short

page_text: or long blasts according to the precise duration required for signalling or other
purposes; the commencement and cessation of the sound being in all cases sharp
and clearly defined. In constructing a Fog-horn embodying our improvements we
adopt substantially the following arrangement. One end of the horn is trumpet-
mouthed; whilst the other end, constituting the reed-chamber is enclosed in a
hollow casing. The reed-chamber communicates with the interior of the trumpet
and is provided laterally with a slot or slots. Immediately over the orifice of each
slot is mounted a tongue having one of its ends free to vibrate. We prefer to
employ either three or four such slots and tongues; and to secure the latter in
position, we employ a ring which surrounds the tongues and the extremity of the
reed-chamber. This ring is retained in place by a washer and nut, the latter being
screwed to a shank on the extremity of the reed-chamber. The tongues may be
further secured by keys driven inside or outside the ends of the tongues embraced
by the retaining ring. The trumpet pipe projecting on one side of the casing is
counterbalanced by a weight mounted on a horn projecting from the opposite side
thereof; or the pipe itself may assume a volute form. The casing is supported on
a hollow standard through which the steam or other aeriform fluid under pressure
gains access to the reed-chamber. In this standard is conveniently disposed the
blast controlling apparatus, consisting of the double ported cylinder or chamber
and transversely perforated plunger previously described. The lower part of the
standard is received in a stuffing box, and the whole apparatus thus adapted for
being readily rotated and the trumpet pointed in any desired horizontal direction.
In cases where, for signalling or other purposes, it is desired to vary the pitch
of the sound produced; the casing may be divided into two compartments. That
portion of the reed-chamber enclosed within one of these compartments is provided
with tongues and slots of a particular length whilst the portion of the reed-
chamber appertaining to the other compartment is furnished with longer or shorter
tongues and slots. By suitable valve apparatus the operating fluid is directed into
one or other of these compartments at pleasure and the pitch of the sound varied
according to which tongue or set of tongues is put in operation. According to
another method of regulating or varying the pitch of the sound, we mount. a,
sliding ring, moveable clip or equivalent device in such a manner that it may be
slid upon or forced against the tongue or tongues at a point, nearer to or further
from their fixed ends. By this means the free or vibrating portion is altered in
length and, the tone of the note produced varied accordingly...