AN IMPROVED REGISTERING INDEX FOR GAS AND OTHER METERS
Year: 1857

page_text: PROVISIONAL SPECIFICATION left by John Carnaby at the Office of
the Commissioners of Patents, with his Petition, on the 19th May 1857.
I, JOHN CARNABY, of Snow Hill, in the City of London, Gas Apparatus
Maker, do hereby declare the nature of the said Invention for "AN IMPROVED
REGISTERING INDEX FOR GAS AND OTHER METERS," to be as follows:-
On the shaft or harbour, driven by the worm shaft, in gas meters I place a
wheel with one tooth; this wheel drives a second, which is so toothed as to
make one-tenth of a revolution when the first wheel has made one revolution.
On the second wheel I make one of the teeth thicker than the others, so that
it may project beyond the surface of them, and work a third wheel in the same
manner that the first wheel works the second, and so I continue from wheel
to wheel for as many as may be required to mark the quantity of gas or other
fluid passing. through the meter. When it is required to express the quantity
by other than decimal proportions, I use other wheels suitable for the purpose.
To lock the second wheel and keep it stationary while the first is making one
revolution, the third stationary while the second is making one revolution, and
so on, I have wheels without teeth placed on the same harbours as the
teethed wheels, and against their respective surfaces, or I have a rim forming
an irregular circle on the face of the teethed wheels. I have suitable levers,
each with a tooth at one end, made to fit between the teeth of the wheels,
the opposite ends being heavier than the toothed ends. These levers move on

page_text: pins placed on the index case just above and between the wheels before
described. The heavy ends of the levers being adjusted to work against the
edge of the wheels without teeth, or against the rim before mentioned, are by
this means kept up, and the toothed ends of the levers retained between the
teeth of the respective wheels; hence, the second wheel will be locked and
kept stationary until the first. has made one revolution; the third will be
stationary until the second has made one revolution, and so on. To
remove the toothed ends of the levers from between the teeth of the wheels, I
have this contrivance :-I alter the circular form of the wheel or rim on which
the heavy end of the lever rests in one part, so as to admit of the heavy end
of the lever falling sufficiently to raise the opposite end and unlock the wheel.
I so manage that when the tooth on the first wheel, the protruding tooth on
the second wheel, and on the others respectively, are coming into gear with
the wheels which they are to work, the heavy ends of the levers drop at
the same time; or, to lock and unlock the teethed wheels, as before described,
I have a groove on the surface of the teethed wheels of circular form, except
at one part, where it is of chord-like or other suitable form. I have a pin in
the untoothed end of the lever, before described, which goes into the groove
and keeps the untoothed end of the lever in a proper position to retain the
tooth on the other end, between the teeth of the wheel required to be locked.
When the chord-like part of the groove of the moving wheel comes against
the untoothed end of the lever, that end is depressed, and the toothed end is
lifted from between the teeth of the consecutive wheel, and so remains until it
has made the required proportion of a revolution; or, I have eccentric wheels
or rims on the surfaces of the teethed wheels, the ends of the levers with
which they come in contact being of a fork-like, or other suitable form. I fix
the hands or the dials on the ends of the harbours in the usual manner.