AN IMPROVED MEANS OR CON- TRIVANCE FOR COMPENSATING OR COUNTERACTING THE EXPANSION AND " PROVISIONAL SPECIFICATION
Year: 1881

page_text: LETTERS PATENT to Henry Whitehead, of Bucknall, in the County of
Stafford, Coal Merchant, and Thomas Dodd, of Winsford, in the County of
Chester, Engineer, for an Invention of AN IMPROVED MEANS OR CON-
TRIVANCE FOR COMPENSATING OR COUNTERACTING THE EXPANSION AND
"
PROVISIONAL SPECIFICATION left by the said Henry Whitehead and Thomas
Dodd at the Office of the Commissioners of Patents on the 26th May 1881.
" AN
HENRY WHITEHEAD, of Bucknall, in the County of Stafford, Coal Merchant,
and THOMAS DODD, of Winsford, in the County of Chester, Engineer.
IMPROVED MEANS OR CONTRIVANCE FOR COMPENSATING OR COUNTERACTING THE
EXPANSION AND CONTRACTION OF RAILWAY SIGNAL WIRES."
The nature of this Invention is explained by the title, and it is carried into effect
substantially in the following manner :- -We provide a standard of convenient
height and size, the said standard being of cast iron or such other material as may
be found most desirable.
The
Near to the top of this standard there is pin or stud, and upon this one or more
of the "compensaters" hereinafter described is caused to move or revolve.
compensater consists of a lever having three angles, upon one of which is placed a
balance weight, which is for the purpose of drawing down the signal arm and
taking up the expansion of the wires when required.
On each of the other two angles there is a grooved pulley of suitable diameter,
and about three inches in width in its grooves.
A chain is then provided which passes round each of the two pulleys.
The compensater is then fixed half way between the signalman's box and the
signal post, and a wire is attached to one end of the chain before named, and carried
forward and attached to the lever in the signalman's box.
Pavice 1
Another wire is attached

page_text: to the other end of the chain, and is carried forward and attached to the lever
connected with the signal arm near to the foot of the signal post. These two wires
being of similar length, the expansion or contraction is equal on each side of the
compensater, and any expansion of the wires will cause the balance weight on the
compensater to descend, when one of the grooved pulleys will be raised, and
the other grooved pulley will be lowered to the extent of the expansion.
In case of contraction the action of the grooved pulleys will be reversed, and the
balance weight on the compensater be raised to the extent of the contraction.
Any breakage or parting of the wires will cause the chain to move round the
grooved pulleys, and the signal arm will then be raised.
The introduction of our improved compensater does not alter any of the present
working arrangements for raising and lowering the signal arm, so that it may be
supplied with but little trouble and at a comparatively small cost.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Whitehead and Thomas Dodd in the Great Seal Patent
Office on the 25th November 1881.
<< AN
HENRY WHITEHEAD, of Bucknall, in the County of Stafford, Coal Merchant,
and THOMAS DODD, of Winsford, in the County of Chester, Engineer.
IMPROVED MEANS OR CONTRIVANCE FOR COMPENSATING OR COUNTERACTING THE
EXPANSION AND CONTRACTION OF RAILWAY SIGNAL WIRES."
The nature of this Invention is explained by the title, and it is carried into effect
substantially in the following manner:- -We provide a standard of convenient
height and size, the said standard being of cast iron or such other material as may
be found most desirable. Near to the top of this standard there is a pin or stud,
and upon this one or more of the compensators hereinafter described is caused to
move or revolve. The compensator consists of a lever having three angles, upon
ono of which is placed a balance weight, which is for the purpose of drawing down
the signal arm and taking up the expansion of the wires when required. On each
of the other two angles there is a grooved pulley of suitable diameter.
A chain is then provided which passes round each of the two pulleys.
The compensator is then fixed half way between the signalman's box and the
signal post, and a wire is attached to one end of the chain before named and
carried forward and attached to the lever in the signalman's box. Another wire is
attached to the other end of the chain, and is carried forward and attached to the
lever connected with the signal arm near to the foot of the signal post. These two
wires being of similar length the expansion or contraction is equal on each side of
the compensator, and any expansion of the wires will cause the balance-weight on
the compensator to descend, when one of the grooved pulleys will be raised and
the other grooved pulley will be lowered to the extent of the expansion.
In case of contraction the action of the grooved pulleys will be reversed, and the
balance-weight on the compensator be raised to the extent of the contraction. Any
breakage or parting of the wires will cause the chain to move round the grooved
pulleys, and the signal arm will then be raised to "danger."
The introduction of our improved compensator does not alter any of the present
working arrangements for raising and lowering the signal arm, so that it may be
supplied with but little trouble and at a comparatively small cost.
That our Invention may be fully understood, we have annexed Drawings thereof
which we will now proceed to describe.
elevation; Figure III., a
general arrangement of a
Similar letters of reference
Figure 1. is a front elevation; Figure II., an end
sectional plan; and Figure IV., an elevation of the
compensator constructed according to our Invention.
are employed to indicate like parts in all the Figures.
The Drawings shew a single compensator for one signal wire only, but by
providing a suitable standard two or more compensators may be arranged to work
side by side on one axis, as will be readily understood. A is a standard firmly
bolted down to a suitable foundation, and carrying a pin or stud B upon which
rotates the triple arm C, one arm of which (C') carries a balance-weight D, while
the remaining arms (C³, C¹³,) carry two pins or studs E, E¹, upon which are placed
the grooved pulleys F, F. A chain G passes round the two grooved pulleys F, F',
in the direction shewn.
In Figure IV. the compensator is shewn placed halfway between the bell-crank H
of the signalman's box and the signal post I, and is connected to the said bell-crank
by a wire H, and to the chain K of the signal post by a wire 1. The full lines
shew the position of all the parts when the signal arm is raised, and the dotted
lines shew the altered positions when the signal arm has been lowered.

page_text: The balance weight D of the compensator keeps the wires H¹, I¹, tight,
notwithstanding variations in their length. The two wires being of equal length
will expand and contract in equal proportion; when they expand the grooved
pulley F will be raised, and the grooved pulley F will be lowered, and the
expansion of the wires will be thereby taken up. When they contract an opposite
movement will take place. The balance-weight D also serves to pull down the
signal arm in opposition to the balance-weight L of the signal post, when the signal
lever M is moved into the position shewn in dotted lines.
In the event of breakage of either of the wires the chain G will be free to move,
carrying round the grooved pulleys to the required extent, and the signal arm will
be raised to or kept at the point of "danger" by the unbalanced action of the
balance-weight L until the wire has been repaired.
As a modification of our Invention the chain G, G, need not be in one continuous
length, as shewn in the Drawings, but may be attached to convenient parts of the
triple arm C near to each end of the bars C and C³ respectively by two shackles or
otherwise. In this case the triple arm and the grooved pulleys are, by preference,
cast in one piece. And as a further modification of our Invention the two pins or
studs E, E', may form part of the principal casting.
Having now described the nature of our Invention, and the manner in which
the same may be carried into effect, we desire it to be understood that without
limiting ourselves to the precise details hereinbefore mentioned, as these may be to
some extent varied or modified without departing from the nature of our said
Invention, we desire it to be understood that what we desire to claim by the
present Letters Patent is,-
A compensator for signal wires having a working arm, grooved pulleys, and a
balance-weight, substantially as and for the purpose hereinbefore described, and as
illustrated in the accompanying Drawings.
In witness whereof, we, the said Henry Whitehead and Thomas Dodd, have
hereunto set our hands and seals, this Twenty fourth day of November
1001
Witness,
CHARLES WELCH.
HENRY WHITEHEAD. (L.S.)
THOMAS DODD.
(L.S.)