IM- PROVEMENTS IN THE MODE OF AND MEANS FOR REGULATING AND REGISTERING THE TENSION OF PIANOFORTE STRINGS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by George Haseltine at the Office of
the Commissioners of Patents, with his Petition, on the 29th May 1866.
-A communication from abroad by Levi Lincoln Tower, of Boston,
Massachusetts, United States of America.
I, GEORGE HASELTINE, of the "International Patent Office," No. 8,
Southampton Buildings, Chancery Lane, in the County of Middlesex, Civil
Engineer, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN THE MODE OF AND MEANS FOR REGULATING AND REGISTERING THE
TENSION OF PIANOFORTE STRINGS," a communication, to be as follows:-
The nature of the said Invention consists, first, in the arrangement of a
lever supported at its front end upon a knife-edge prop, in combination with
a tension slide on the said lever operated by a screw for the purpose of regu-
lating the tension of the strings of pianofortes; and, secondly, in the method
of registering the tension of the strings by means of a dial plate and indicator,
operated by the back end of the lever, in consequence of the tension slide
being moved out or in on it in the operation of tuning the piano, thereby
depressing or elevating the end of the lever, and in doing so operating the
pointer to register the tension or tone of the strings of the piano. But to
describe the said Invention more fully I will refer to the accompanying
Drawings forming a part of this description, the same letters of reference,
wherever they occur, referring to like parts.
The accompanying Drawing shows a perspective view of the mechanism as
arranged in a vertical pianoforte.

page_text: Letter R represents the frame; S is a cross bar, on which is secured a
knife-edge prop T, on the edge of which is adjusted the front end of a lever C
at right angles or nearly so to the prop. Through the head C of the lever
is inserted a set screw D, which is operated by a key to move a tension slide B
on the upper edge of the lever C. The object of this adjustment of the slide
is to regulate the tension of the strings U, which pass around it and back
through channels I formed in the sides of the head piece C, and thence down
over a roller bridge J secured to the face of the cross bar S to pins A in the
frame R, where the ends of the strings are secured.
It will be apparent from this arrangement that by forcing the slide B out
or back on the lever by means of the screw D the tension of the strings is
readily graduated to any tone or pitch note required to tune the piano, and at
the same time register the tone on the dial plate L, by means of the indicator
or pointer E, operated by the outer end of the lever C, when it is elevated or
depressed in consequence of the slide B moving out or back on it in the act
of graduating the tension of the strings. Thus if the indicator stands at zero
point F, and the slide B is moved out towards the end of the lever C, it will
be depressed, and the indicator moved one or more degrees to the left to
register the tension or pitch note of the strings; but if the pitch note is too
bigh and the slide retracted on the lever, then its point rises and carries the
indicator to the right of zero point one or more degrees to lessen the tension
of the strings to produce the required pitch note. It will thus be seen that
any pitch note of the strings once registered on the dial may be restored by
simple inspection on turning the set screw, without reference to any previous
knowledge of music.