IMPROVEMENTS IN RAILWAY SIGNALS
Year: 1877

page_text: LETTERS PATENT to Tempest Anderson, of Stonegate, in the City and County
of York, for the Invention of " IMPROVEMENTS IN RAILWAY SIGNALS."
PROVISIONAL SPECIFICATION left by the said Tempest Anderson at the
Office of the Commissioners of Patents on the 30th April 1877.
TEMPEST ANDERSON, of Stonegate, in the City and County of York.
MENTS IN RAILWAY SIGNALS."
"IMPROVE
"
My Invention relates to means of working the semaphore signals of railways in
such a manner that in the ordinary working the signal is pulled to danger by
tightening the wire, and falls to safety when the wire is slackened; yet if the pull
should accidentally break, the signal will be raised automatically to the "danger
attitude and will remain in that attitude until the pull is properly. repaired. For
this purpose I connect the vertical rod on the signal post to a lever arm projecting
from the axis of the semaphore in a direction opposite to that of the semaphore arm
itself, so that when the vertical rod is slacked upwards, the semaphore arm is
permitted to descend by its own weight to the "safety" attitude; and when the
vertical rod is pulled down, the semaphore arm is raised to "danger."
At or near the signal post I divide the signal pull into two branches or links, the
one of which is attached to the vertical rod, and the other to a piece of chain or
band which passes over a pulley, and has attached to it a weight which is more
than sufficient to counterbalance the semaphore arm; or the second branch of the
pull may be linked to the arm of a weighted lever. While the pull remains entire,
when it is drawn, the semaphore arm is raised to "danger," and the weight is also
raised; and when it is slacked, the semaphore arm is permitted to descend to
"safety," the weight also descending. If, however, the pull should break, then the
weight, being no longer held up by the one branch of the pull, descends farther, and
in doing so, pulls down the vertical rod, and so raises the semaphore to " danger."
This action of the weight on the vertical rod results from the connection of the one
to the other by the two branches or links of the pull; or a stud or stop may be
provided on the vertical rod, on which the weight or the loaded lever will bear
when the fracture of the pull leaves it free to descend beyond its normal distance.

page_text: According to a modified form of this apparatus, the vertical rod is linked to the
arm of a lever, the other arm of which is loaded and linked to the signal pull. The
fulcrum of this lever on the post works in a slot, so that it cannot be pulled upwards
beyond a certain point, but is free to descend. In its normal condition the fulcrum
is at the one end of the slot, and then the tightening of the signal pull raises the
loaded end of the lever, and lowering the opposite end, and the vertical rod raises
the semaphore to "danger," whilst the slacking of the pull lets the semaphore
descend to "safety." If, however, the pull should break, then the lever with its
fulcrum descends bodily; and the weight, now acting directly on the vertical rod,
raises the semaphore to "danger."
The slot for the fulcrum may be in the lever itself, or may simply be a notch in
the upper edge of the lever bearing against a fulcrum fixed on the post.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Tempest Anderson in the Great Seal Patent Office on the 29th
October 1877..
TEMPEST ANDERSON, of Stonegate, in the City and County of York. "IMPROVE-
MENTS IN RAILWAY SIGNALS."
My Invention relates to means of working the semaphore signals of railways in
such a manner that in the ordinary working the signal is pulled to danger by
tightening the wire, and falls to safety when the wire is slackened; yet if the pull
should accidentally break, the signal will be raised automatically to the "danger"
attitude, and will remain in that attitude until the pull is properly repaired. For
this purpose I connect the vertical rod on the signal post to a lever arm projecting
from the axis of the semaphore in a direction opposite to that of the semaphore arm
itself, so that when the vertical rod is slacked upwards, the semaphore arm is
permitted to descend by its own weight to the "safety" attitude; and when the
vertical rod is pulled down, the semaphore arm is raised to "danger."
*
At or near the signal post I divide the signal pull into two branches or links, the
one of which is attached to the vertical rod, and the other to a piece of chain or
band which passes over a pulley, and has attached to it a weight which is more
than sufficient to counterbalance the semaphore arm; or the second branch of the
pull may be linked to the arm of a weighted lever. While the pull remains entire,
when it is drawn, the semaphore arm is raised to "danger," and the weight is also
raised; and when it is slacked, the semaphore arm is permitted to descend to
'safety," the weight also descending. If, however, the pull should break, then the
weight, being no longer held up by the one branch of the pull, descends farther, and
in doing so, pulls down the vertical rod, and so raises the semaphore to "danger"
This action of the weight on the vertical rod results from the connection of the one
to the other by the two branches or links of the pull; or a stud or step may be
provided on the vertical rod, on which the weight or the loaded lever will
bear when the fracture of the pull leaves it free to descend beyond its normal
distance.
According to a modified form of this apparatus, the vertical rod is linked to the
arm of a lever, the other arm of which is loaded and linked to the signal pull. The
fulcrum of this lever on the post works in a slot, so that it cannot be pulled upwards
beyond a certain point, but it is free to descend. In its norinal condition the fulcrum
is at the one end of the slot, and then the tightening of the signal pull raises the
loaded end of the lever, and lowering the opposite end, and the vertical rod raises
the semaphore to " danger," whilst the slacking of the pull lets the semaphore
descend to "safety," If, however, the pull should break, then the lever with its
fulcrum descends bodily; and the weight now acting directly on the vertical rod,
raises the semaphore to "danger."

page_text: The slot for the fulcrum may be in the lever itself, or may simply be a notch in
the upper edge of the lever bearing against a fulcrum fixed on the post.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents a front view of a signal post with safety apparatus according to
my Invention for working the semaphore arm A. The signal pull P, which may be
a chain, rod, or wire, extending from the signal lever to the post, is at the post
divided into two branches p¹, p². The one branch pl passes round a pulley, and is
attached to the signal rod S; the other branch p2 passes round a pulley, and is
attached to a weight W (or it might be a loaded lever) more than sufficient to
counterbalance the semaphore arm A. When the pull P is slacked out, the weight
W and arm A are allowed to descend; but when P is tightened up, both are
raised. If, however, the pull P should accidentally break, then the weight W
descends, straightening the bight of the two branch chains p¹, p³, and so draws
down the rod S, raising the arm A to "danger."
It is obvious that for the sliding weight W, shewn in Fig. 1, a loaded lever may
be substituted. When the pull P is of considerable length, any known means of
allowing for variations in its length, due to changes of temperature, may be applied
to it.
I have shewn an arrangement for this purpose at Fig. 1º, to which, however, I
make no claim as part of my present Invention.
According to this arrangement, the pull P is attached to a lever C counter-
weighted sufficiently to take up the slack of the pull, and to keep up the weight
W and the arm A in its "danger" attitude; but the lever C being free on its
pivot, allows the expansion or contraction of the pull P.
The signal hand lever L has mounted on it a pawl, which in the position of L,
shewn in Fig. 1a, by means of a stud bearing on a horn H, is kept disengaged
from à toothed segment on the lever C. When the lever L begins to bo moved
over, the pawl drops into gear with one or other of the teeth on C, and by the
farther movement of L, the lever C is also moved, and. the pull P is slacked out,
allowing the semaphore arm to descend to the "safety" attitude.
Fig. 2 is a front view of a signal post, with a modified form of safety apparatus
according to my Invention. In this case the pull P is attached to the signal rod S,
and is also linked to a counterweighted lever M. When the pull P is slacked out,
the arm A is lowered to "safety;" and when P is tightened, the weighted arm of M
is raised, and the arm A is also raised to "danger," as shewn in the Figure. Should
the pull P break, the weighted arm of. M descends, and bearing on a stud or tappet
8 on the signal rod S, draws down the rod, and so raises the arm A "to danger."
By means of several levers M, and their pulls, the signal may be controlled from
several places.
Another modification of safety signal apparatus, according to my Invention, is
shewn in front view at Fig. 3. In this case the pull P is passed over a pulley, and
attached to the loaded arm of a lever N, to the opposite arm of which is linked the
signal rod S.. The lever N is made with a slotted hole taking on to the fulcrum
stud n.
When the pull is slacked out, the loaded arm of N descends, and the other
arm ascending causes or permits the semaphore arm A to descend to "safety;" when
the pull P is tightened up, the weighted arm of N is raised, the rod S is pulled
down, and the arm A is raised to "danger." Should the pull P break, then the
lever N drops into the position indicated by the dotted lines N¹, its slotted hole
permitting it to slide down, and the rod S is thus drawn down, raising the arm A
to " danger."
The guide pulley for the pull P, shewn in Fig. 3, may be dispensed with by
employing a three-arm lever N, as shewn in Fig. 4.
Having thus described the nature of my Invention, and in what manner the same
is to be performed, I claim,-
First. The use of safety signal apparatus constructed and operating, substantially
as herein described with reference to Fig. 1 of the accompanying Drawings, the said

page_text: apparatus being characterised by the division of the signal pull into two branches
connected respectively to the semaphore arm, and to a load more than sufficient to
counterbalance the same.
Second. The modified form of safety signal apparatus, substantially as herein
described with reference to Fig. 2 of the accompanying Drawings, in which a branch
of the pull is connected to a loaded lever.
Third. The modified form of safety signal apparatus, substantially as herein
described with reference to Fig. 3 of the accompanying Drawings, in which the
signal pull and signal rod are connected to a loaded lever having its fulcrum in a
slot, so arranged that on the breaking of the pull, the position of the fulcrum is
changed, causing the signal to move to "danger."
In witness whereof, I, the said Tempest Anderson, have hereunto set my
hand and seal, this Twenty-sixth day of October, in the year of our Lord
One thousand eight hundred and seventy-seven.
TEMPEST ANDERSON. (LS.)