IMPROVEMENTS IN BELLS AND GONGS, AND IN THEIR MANUFACTURE
Year: 1859

page_text: PROVISIONAL SPECIFICATION left by Richard Howson at the Office
of the Commissioners of Patents, with his Petition, on the 12th
November 1859.
I, RICHARD HOWSON, of the City of York, Engineer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN BELLS AND GONGS, AND
IN THEIR MANUFACTURE," to be as follows:-
If two or more metallic rings be taken of different diameters, but tuned
together so as to be in unison when struck, their thicknesses will be found to
be related to each other in the ratio of the squares of their diameters, such
diameters being taken sometimes across their outer circumferences, and in
other cases across circles contained within the circumferences according to the
shape of the rings employed.
My Invention consists, firstly, in the application of this law (or such an
approximation to it as is practicable) to regulate the relative thickness of the
metal of a bell at all parts thereof, except at the lip, the crown, and the part
adjacent to the crown. The lip may either terminate abruptly, or may be
tapered off in the usual manner, and the crown (with sometimes a small
portion of the waist) I prefer to make thicker than usual, and of an irregular
thickness. With respect to the shape of the bell, I prefer that hemispherical™
type which brings the "sound bow" to such a position that its vibrations take
place at right angles to the axis of the bell, or nearly so, in contradistinction
to the ordinary shape in large bells, which gives to the sound bow an outward
curvature. This type, as thus described, is capable of various modifications.
My Invention consists, secondly, in an improved shape of gong, which may
be described as follows:-Suppose the heel of a tuning fork to be fixed to an
axis with the prongs projecting at right angles thereto, and with the two ends

page_text: of the axis and the two tips of the prongs all in the same plane. Suppose
now the axis to be turned round, so as to complete an entire circle, the figure
which the fork describes will represent the shape of the gong. The form thus
resulting will be capable of modification in the same manner, as the fork itself
may be supposed to assume different shapes, and it will be understood that
here also the law of the squares, as above expressed, is equally applicable. In
the case of both bells and gongs, it will be also observable, that the application
of this law will frequently render the metal very thin when the diameter
becomes small. At the point, therefore, where this takes place to an injurious
extent, I sometimes suddenly increase the thickness to such an amount as will
give the octave to the original note, or some harmonic of it in the ascending
scale, and I then proceed again to taper off the new thickness in accordance
with the same law. On the other hand, when the diameter increases rapidly,
the metal will sometimes become thicker than is convenient, and I accordingly,
in such case, suddenly reduce the thickness, so as to give an octave below, or
an harmonic in the descending scale.
My Invention consists, thirdly, in casting bells with their crowns downward
instead of upward, as ordinarily practised, and in heating the mould by means
of a fire placed within the inverted core.
Fourthly, whereas great injury is often caused to the molecular structure of
bells, in consequence of the rigidity of the core not allowing the metal to
contract freely during the process of cooling, my Invention consists in giving
unusual freedom for contraction by the use of cores which are collapsible. The
foundations of such cores I accordingly make of metal, but instead of having
them permanently rigid, I give them a segmental construction, and I connect
the segments together by means of screws or keys, in such a manner that
when the screws or keys are removed or slackened, the segments will be at
liberty to yield inwards to a limited extent.
Fifthly, my Invention cousists in using cast-iron moulds for the manufacture
of small bells and gongs, or what are known among moulders as "chills." I
do not, however, use the chills in a cold state, but I heat them in a furnace,
or otherwise, previously to casting, and I keep them hot, by preference,
subsequently to casting, in order to effect a slow rate of cooling.
Sixthly, in drawing off the air from moulds during the time of casting by
means of air pumps.