IMPROVEMENTS IN THE MEANS AND APPARATUS FOR ALLOWING FOR VARIATIONS IN THE LENGTH OF SIGNAL PULLS
Year: 1875

page_text: LETTERS PATENT to Edward Tyer, of No. 4, Old Street, in the County
of Middlesex, for the Invention of "IMPROVEMENTS IN THE MEANS
AND APPARATUS FOR ALLOWING FOR VARIATIONS IN THE LENGTH OF SIGNAL
PULLS."
Scaled the 20th December 1875, and dated the 18th October 1875.
PROVISIONAL SPECIFICATION left by the said Edward Tyer at the
Office of the Commissioners of Patents, with his Petition, on the
18th October 1875.
I, EDWARD TYER, of No. 4, Old Street, in the County of Middlesex,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MEANS AND APPARATUS FOR ALLOWING FOR VARIATIONS IN THE LENGTH OF
SIGNAL PULLS," to be as follows:-
:-
My Invention relates to a method of and apparatus for allowing for
variations in the length of the wires, chains, or rods which connect a
railway or other similar signal to the lever that works it.

page_text: In any convenient position near the lever that works the signal I
mount on an arm connected to that lever a chain pulley round which I
pass a portion of chain connected to the signal pull at one end, and
having attached to its other end a weight sufficient to take up the slack
of the signal pull. On the axis of this chain pulley I fix a brake wheel
and surround it by a flexible band connected to a weight or weighted
lever, which when the signal lever is in its normal position rests upon a
stop, leaving the brake wheel and chain pulley free, but which being
raised off its stop when the signal lever is moved brings the brake into
action and prevents the chain pulley from revolving. Thus so long as
the signal lever is not in use for working the signal, the chain pulley
being free to revolve, the signal pull can freely expand or contract the
weight on the chain, keeping it always under the required tension; but
as soon as the signal lever is moved for the purpose of working the
signal the chain pulley is held by means of the brake, and the necessary
strain can then be transmitted through the pull.
Instead of employing a brake strap surrounding the brake wheel, as
described above, other known forms of brakes may be used, so arranged
that they are only brought into action by the movement of the signal
lever.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Tyer in the Great Seal Patent Office on
the 15th April 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
TYER, of No. 4, Old Street, in the County of Middlesex, send 2
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of October, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Edward Tyer, Her special
license that I, the said Edward Tyer, my executors, administrators, and
assigns, or such others as I, the said Edward Tyer, my executors, ad-
ministrators, and assigns, should at any time agree with, and no

page_text: others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE MEANS AND APPARATUS FOR ALLOWING FOR VARIATIONS IN THE LENGTH OF
SIGNAL PULLS," upon the condition (amongst others) that I, the said
Edward Tyer, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Edward Tyer, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement thereof, reference being had to the accom-
panying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say:-
My Invention relates to a method of and apparatus for allowing for
variations in the length of the wires, chains, or rods which connect a
railway or other similar signal to the lever that works it.
In any convenient position near the lever that works the signal I
mount on an arm connected to that lever a chain pulley round which I
pass a portion of chain connected to the signal pull at one end, and
having attached to its other end a weight sufficient to take up the slack
of the signal pull. On the axis of this chain pulley I fix a brake wheel
and surround it by a flexible band connected to a weight or weighted
lever, which when the signal lever is in its normal position rests upon a
stop, leaving the brake wheel and chain pulley free, but which being
raised off its stop when the signal lever is moved brings the brake into
action and prevents the chain pulley from revolving. Thus so long as
the signal lever is not in use for working the signal, the chain pulley
being free to revolve, the signal pull can freely expand or contract, the
weight on the chain keeping it always under the required tension; but
as soon as the signal lever is moved for the purpose of working the

page_text: signal the chain pulley is held by means of the brake, and the necessary
strain can then be transmitted through the pull.
Instead of employing a brake strap surrounding the brake wheel, as
described above, other known forms of brakes may be used, so arranged
that they are only brought into action by the movement of the signal 5
lever
Fig. 1 represents a side view of a railway signal lever and its con-
nection to a semaphore signal, the lever being fitted with one form of
apparatus, according to my Invention, for allowing for variations in the
length of the signal pull.
Fig. 2 is a side view, and Fig. 3 a plan to an enlarged scale of the
end of the signal lever with its brake apparatus as I will now describe.
On the arm A of the signal lever is mounted a chain pulley B over
which passes a chain attached at one end to the signal pull C, and at
the other end to a weight D sufficiently heavy to take up the slack of the
signal pull when it is expanded in length by heat or tension. On the axis
of the chain pulley B is fixed a brake wheel E surrounded by a flexible
brake strap F, one end of which is jointed by a pin at a to the arm A,
and the other end is jointed by a pin at g to a forked lever G mounted
on the arm A and carrying an adjustable weight H. Under the pro-
jecting end of the lever G is a stop K which may be adjusted in height
by a screw, as shown in Fig. 1. When the signal lever is in its forward
or normal position, letting the semaphore stand at "danger," the arm A
being then down, the end of the lever G rests on the stop K, and the
brake strap F is then slack, leaving the brake wheel E and pulley B
free to revolve, consequently leaving the signal pull C free to expand or
contract, subject only to the tension of the weight D; but when the
signal lever is begun to be moved over for the purpose of lowering the
semaphore then the arm A being raised the lever G is lifted off the
stop K, and the weight H tightens the brake strap F upon the brake
wheel, preventing it from revolving, whereupon the movement of the
signal lever necessarily draws in the pull C, allowing the semaphore to
drop.

page_text: brake wheel E embraced by a brake strap F, one end of which is jointed
by a pin a to a horn projecting from the lever arm A, and its other end
is jointed by a pin to a weight L. In the normal position of the
lever A the weight L either rests on a platform M or hangs by a chain N
so as to relieve the brake wheel of the friction of the strap F; but when
the arm A is begun to be raised the weight L being no longer sustained
by M or N tightens the strap on the brake wheel so that the movement
of the signal lever necessarily operates on the pull C. In this case the
weight D for tightening the pull C is suspended from an arm of the
lever opposite to A, so that it serves the double purpose of tightening
the signal pull and of acting as a counterweight to render the movement
of the lever more easy for the operator.
Fig. 5 represents a side view of an arrangement, in which instead of
the friction of a brake strap the engagement of a tooth is employed to
effect a rigid connection of the signal pull to the signal lever when the
latter is moved from its normal position. In this case the chain
pulley B having on its axis a toothed wheel E usually rests by its axis
in the forks of a fixed bracket P, the axis passing through slotted holes.
in the arm A of the signal lever. A tooth O on a horn projecting down
from the arm A is in this condition clear of the teeth of the wheel E,
which wheel with the chain pulley B is then free to revolve so as to
allow for expansion or contraction of the signal pull C subject to the
tension of the weight D; but when the arm A is begun to be raised
(the slotted holes permitting it to rise a little without raising the axis
of B) then the tooth O engaging with one or other of the teeth of tho
wheel E prevents that wheel from turning while it is raised by the
farther movement of the signal lever, the said movement consequently
drawing in the signal pull C.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I claim,—
First. The method, substantially as herein described, of allowing for
variations in the length of a signal pull by straining the pull by a weight
attached to a chain passing over a free pulley, which is prevented from
revolving when the signal lever is moved from its normal position.
Second. The use for allowing for variations in the length of a signal
pull, of apparatus consisting of a chain pulley provided with a brake or

page_text: stop which in the normal position of the signal lever leaves the pulley
free to revolve, but which is caused to prevent its revolution by the
movement of the signal lever, substantially as herein described.
In witness whereof, I, the said Edward Tyer, have hereunto
set my hand and seal, this First day of April, in the year
of our Lord One thousand eight hundred and seventy-six.