An Improved Mercurial Compensation Pendulum for Pendulum Clocks of all kinds.
Year: 1891

page_text: Date of Application, 24th Aug., 1891-Accepted, 31st Oct., 1891
COMPLETE SPECIFICATION.
An Improved Mercurial Compensation Pendulum for Pendulum
Clocks of all kinds.
I, SIGMUND RIEFLER, of 29, Karlsplatz, Munic, in the Kingdom of Bavaria,
German Empire, Engineer and Manufacturer do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My invention relates to pendulums known by the name of mercurial-compensation-
pendulums and the object is to increase the compensating effect to the utmost
accuracy.
This object I attain by collecting the mercury merely in the hollow of the
pendulum rod.
Referring to the drawing herewith
The rod a is a straight tube made of any suitable material preferably of
steel. The same is filled up with quicksilver. The height of the column of
mercury is dependent on the weight of the pendulum-bob , on the inner width
of the tube a and also on its weight. The effect the mercury takes upon the
pendulum by the change of temperature is evident. By the fall of the same
the quicksilver shrinks together, thus causing the centre of gravity to lower,
at the same time also the tube shrinks in its length, thus raising the pendulum-
bob and with it the centre of gravity, again when the temperature rises, the
effect will be reversed to the first, that is to say, the mercury expands and thus
raises its centre of gravity, while by the expansion of the tubular rod a the
centre of gravity of the pendulum-bob lowers. By these means an exact
compensation is obtained. The amount of quicksilver to be used for each
pendulum may be carefully calculated, when the same is to be filled, and since
the compensating effect not only is dependent of height and weight of the
mercury-column, but also of the weight of the complete matter, the latter may
be increased or decreased for sake of regulation, without altering the amount of
quicksilver employed. I will now point out the great advantages my new
pendulum has in comparison to other mercurial-compensation-pendulums.
:
Firstly the compensation not only will be an exact one, when the temperature
changes slowly, but also will be as true, when sudden variations of temperature
take place. The reason thereof is this the quantity of quicksilver is distributed
about almost the whole length of the rod, and the same having also close
contact therewith, will partake of the change of temperature almost as soon as
the rod itself does, and therefore the expansion or contraction of the rod and
of the mercury will nearly take place at the same time. In other mercurial-
compensation-pendulums the quicksilver is collected in a vessel at the lower end.
Secondly also differences in the temperature of the air at different parts of
the pendulum rod, will not only influence the rod, but also the mercury and
therefore have no disturbing effect in the compensation. Moreover the pendulum
may be made of any suitable shape as for instance that of a flat disk with
sharp edges, or may be slightly curved like a double concave lens, thereby the
air is easily cut, and little resistance is offered to the same. Finally the
pendulum will be much cheaper, than others, since the amount of quicksilver required
will be only one quarter of that used heretofore.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, declare that what I
claim is :-
:-
1. In a compensation-pendulum for clocks a pendulum rod filled with mercury,

page_text: 2. In a compensation-pendulum for clocks a pendulum-rod filled with mercury
in combination with an ordinary pendulum-bob, as set forth.
Dated this 20th day of August 1891
SIGMUND RIEFLER.
By H. F. Boughton, M.I. Mech. E.,
London, Sheffield, and Barnsley, Agent.