Electrical Contact Apparatus Worked by Passage of a Railway Train.
Year: 1888

page_text: Date of Application, 7th Nov., 1888
Complete Specification Left, 18th July, 1889-Accepted, 31st Aug., 1889
PROVISIONAL SPECIFICATION.
Electrical Contact Apparatus Worked by Passage of a Railway
Train.
I, EDWARD TYER of Ashwin Street, Dalston, London, Electrical Engineer, do
hereby declare the nature of this invention to be as follows:-
Electrical contact apparatus have been proposed to be worked by the passage of a
train over the part of the line where the apparatus is situated, and the movement
required for making the contact has been obtained from the flexure of the rail
caused by the weight of the passing vehicles. A great difficulty has attended the use
of many of these apparatus, due to the fact that, while the contacts remain in a fixed
position, the level of the rail itself is subject to variation, and thus the mechanical
connections from the rail to the contacts become often relatively displaced.
My invention has for its object to overcome this difficulty by providing a form of
contact apparatus which shall be efficient notwithstanding considerable variation of
the relative levels of the rail and the contacts.
For this purpose, 1 fix near the rail a small cylinder provided with a piston, which
may be a somewhat loose fit to the cylinder or may have a small hole through it.
From the bottom of the cylinder a passage leads up to a small basin or cup into
which projects an insulated contact pin. I charge the lower part of the cylinder with
mercury, but not enough to reach up to the cup, and I connect the piston to a suitable
multiplying lever or set of lovers which are also connected to the rail. 1 join the
electrical conductors through which circuit is to be established, the one to the
cylinder or cup and the other to the insulated pin that projects into the cup. So long
as the apparatus is in repose, the circuit remains open, but, when the rail is strained
down by a passing train, the piston making a rapid stroke down causes mercury to
mount up to the cup making contact with the insulated pin. As the level of the
rail varies from time to time, the position of the piston in the cylinder varies also, but
that does not effect the action, because, during repose of the apparatus, mercury is
free to leak past or through the piston without rising to the cup, and it is only when
the piston is rapidly depressed that the mercury is caused to ascend to the cup and
make the contact.
When it is desired that the passage of a train shall effect the opening instead of
the closing of a circuit, the piston is so connected to the rail that the depression of
the rail by a passing train causes the piston to ascend rapidly in the cylinder, and
the apparatus is charged with sufficient mercury to keep the insulated contact pin
usually submerged. By the rapid ascent of the piston mercury is withdrawn from
the cup and contact with the pin is thus broken.
Dated this 7th day of November 1888.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Electrical Contact Apparatus Worked by Passage of a Railway
Train.
I, EDWARD TYER of Ashwin Street Dalston, London, Electrical 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:
Electrical contact apparatus have been proposed to be worked by the passage of a
train over the part of the line where the apparatus is situated and the movement

page_text: required for making the contact has been obtained from the flexure of the rail caused
by the weight of the passing vehicles. A great difficulty has attended the use of
many of these apparatus, duo to the fact that while the contacts remain in a fixed
position, the level of the rail itself is subject to variation and thus the mechanical
connections from the rail to the contacts become often relatively displaced.
My invention has for its object to overcome this difficulty by providing a form of
contact apparatus which shall be efficient notwithstanding considerable variation of
the relative levels of the rail and the contacts.
For this purpose I fix near the rail a small cylinder provided with a piston which
may be a somewhat loose fit to the cylinder or may have a small hole through it.
From the bottom of the cylinder a passage leads up to a small basin or cup into
which projects an insulated contact pin. charge the lower part of the cylinder with
mercury but not enough to reach up to the cup and I connect the piston to a suitable
multiplying lever or set of levers, which are also connected to the rail. I join the
electrical conductors through which circuit is to be established the one to the cylinder
or cup and the other to the insulated pin that projects into the cup. So long as the
apparatus is in repose, the circuit remains open, but when the rail is strained down by
a passing train, the piston making a rapid stroko down causes mercury to mount up
to the cup making contact with the insulated pin. As the level of the rail varies
from time to time, the position of the piston in the cylinder varies also but that does
not affect, the action, because, during repose of the apparatus mercury is free to leak
past or through the piston without rising to the cup and it is only when the piston is
rapidly depressed that the mercury is caused to ascend to the cup and make the
contact.
When it is desired that the passage of a train shall effect the opening instead of
the closing of a circuit the piston is so connected to the rail that the depression of the
rail by a passing train causes the piston to ascend rapidly in the cylinder, and the
apparatus is charged with sufficient mercury to keep the insulated contact pin usually
submerged.
By the rapid ascent of the piston mercury is withdrawn from the cup, and contact
with the pin is thus broken.
Fig. 1 of the accompanying drawings is a side view of contact apparatus according
to my invention operated by the depression of a rail. Figs. 2 and 3 show on an
enlarged scale respectively a vertical section and a plan of the mercury contact.
The short arm of a lever L is inserted in a hole bored in the rail R, and the long
arm of I is connected through a beam B to a piston P which loosely fits a cylinder Ü
or which has a small hole through it as shown in Fig. 2. At the side of the
cylinder and in communication with it by a passage D is a cup M into which
projects through insulating material a wire W. One conductor E of the circuit is
connected to the body of the cylinder the other conductor is connected to tho
insulated wire W. The cylinder C, passage D and cup M are charged with mercury
to a level some distance below the wire W, so that, while the apparatus is in repose,
there is no electrical connection between the conductors E and F, and their circuit is
therefore open. But, when the rail R is depressed by the passage of a train over it,
the piston P is rapidly depressed causing mercury to rise in the cup M making
contact with the wiro W and thereby closing the circuit of E and F. When, owing
to subsidence or other causes, there is a change in the relative levels of the rail R and
of the cylinder C, the piston P becomes more or less deeply immersed in the mercury
which, being free to pass the piston, nevertheless maintains the same level out of
contact with the wire W, but the sudden depression of the piston P, whatever bo
the position that it occupies in the cylinder, causes the mercury to rise in M and
make contact with W.
The apparatus may be so arranged that the circuit of E and F remains normally
closed, but it is opened by the passage of a train along the rail. In this case the
piston P is connected directly to the long arm of the lever L without the intervention
of the beam B, so that, when the rail is depressed the piston P is rapidly raised.
Also, in this case, the level of the mercury is such as to keep the wire W usually

page_text: immersed in it and so to keep the circuit of E and F closed. But when by the
depression of the rail R the piston P is rapidly raised the mercury M descends
exposing the wire W and so opening the circuit of E and F.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
-
Electrical contact apparatus wherein a loose or perforated piston being rapidly
moved in a cylinder by the depression of a rail on the passage of a train, causes
mercury contained in the cylinder and in a cup communicating with it to make or
break contact with a wire in the cup, thereby closing or opening an electric circuit,
arranged and operating substantially as and for the purposes herein set forth.
Dated this 15th day of July 1889.
ABEL & IMRAY,
Agents for the Applicant.