Year: 1886

page_text: I JOHN GERHARDT of 39 Mance Street Montreal in the Province of Quebec and
Dominion of Canada Mechanical Engineer 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:-
The object of my Invention is to provide an accurate and reliable compensating
pendulum which shall be cheap, durable, and not liable to get out of order.
To this end, my Invention consists principally of a compensating rod and
pendulum rod, both made of the same metal, combined with pivoted connecting
devices supported at one end by the compensating rod, and from which the
pendulum is suspended, so that the contraction of the compensating rod will lower
the pendulum and its expansion will raise the pendulum, in exactly the degree
that the pendulum itself expands and contracts under the influence of the same
temperature with the compensating rod.
The Invention also consists of means for adjusting the compensating rod
whereby the said rod may be used as a regulator for the pendulum.
The Invention also consists of the construction arrangement and combination of
parts, all as herein after described and claimed.
Reference is to be had to the accompanying drawings forming a part of this
specification, in which figure 1 is a front elevation of my new and improved
compensating pendulum, and figure 2 is an edge view of the same. Similar letters
of reference indicate corresponding parts in both the figures.
A represents the compensating rod, which is made of the same metal as the
pendulum B, or of a metal that expands and contracts under the influence of heat
and cold in equal degree with the metal of the pendulum. The compensating
rod A is fixed at its lower end to the bracket C, so that any contraction or
expansion of said rod will take effect at its upper end. Connected to the upper
end of the compensating rod A is the lever D pivoted at d. The pendulum B is
connected to the lever Ď by the short lever E and the connecting link F, so that
the up and down movement of the lever D caused by the expansion and contraction
of the compensating rod A will raise and lower the pendulum B. The rod A
should be of suitable length, and the levers D, E, should be so arranged that the
movement of the free end of the lever E will be just equal to the expansion and
contraction of the rod A, so that when the rod A and pendulum contract, the

page_text: lever E will be lowered to compensate for the contraction of the pendulum, and
when the pendulum B and rod A expand the lever E will lift the pendulum an
equal degree and thus accurately compensate for the effect that changes in
temperature may have upon the pendulum. The pendulum is connected to the
end of the lever E by the thin spring a which is held between the opposite
cheeks b b which constitute the point of oscillation of the pendulum, so that the
length of the pendulum is calculated from this point to its lower end. For
regulating the length of the pendulum to increase or diminish its speed of
oscillation, the bob c is not raised or lowered upon its rod as with a common
pendulum, but the compensating rod A is raised or lowered by turning the nut d¹
which will communicate a like movement to the pendulum through the levers D E.
An index f and pointer g are combined with the rod A. to assist in regulating the
pendulum.
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Constructed as described, the pendulum is not only accurately self-compensating
but is cheap, and not liable to get out of order, and serves also as the regulating
rod for the pendulum.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed; I declare that what
I claim is;
1. The combination with the pendulum B of the compensating rod A, supported
upon the projection C, and connected to the pendulum by the connected levers D, E,
the pendulum spring being held between the cheeks b, substantially as described.
2. The pendulum B and cheeks b b in combination with the supported com-
pensating rod A and suitable pivoted connecting devices connecting the compensating
rod with the pendulum, substantially as described.
3. The compensating rod A made longitudinally adjustable in combination with
the pendulum and the pivoted connected and connecting levers D, E, substantially
as and for the purposes described.
4. The combination with the compensating lever A and adjusting nut d¹³ of the
index f and pointer g substantially as described.