Improvements in Treadles for Use in Railway Signalling.
Year: 1893

page_text: Date of Application, 13th Dec., 1893
Complete Specification Left, 13th Sept., 1894-Accepted, 13th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in Treadles for Use in Railway Signalling.
I, JOHN GEORGE. DIXON, of 98 Norman Road, Birkby, in the County of York,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved form of treadle for actuating an electrical
contact for any purpose in railway signalling where it is required that the passage
of a train or vehicle shall release, lock or actuate block instruments, signals,
bells, indicators, or any devices employed for the purposes of railway signalling.
My invention consists of a lever fulcrumed at one end below rail level, the other
end being normally raised above rail level so as to be struck downwards by the
tread of the first wheel. At right angles to the said rail lever and attached to it is
a transverse. bar or lever; the other end of the said transverse lever operates a
piston rod and piston, a valve of leather or other suitable material being provided
at the end of the piston.
There are two electrical contacts which I actuate in connection with my
invention, one being a making contact, that is to say, the contact normally broken,
and in this case the contact would be a prolonged making one; the other contact
is normally made and would be broken instantaneously. To effect the latter I
arrange any known means of spring, say at the bottom of the cylinder, with a
contact at the end of the piston rod projecting through the piston. In the normal
position of the piston in the cylinder contact would be made and the rise of the
piston through the deflection of the treadle would instantaneously break the contact.
and the contact would remain broken until the return of the piston in the cylinder.
The other would be, say for example, a hole bored in the wall of the cylinder, in
which is inserted an insulated plug containing a contact pin, this pin would be
normally above the pistou and upon the rise of the piston through the deflection of
the treadle contact would be instantaneously made but would be prolonged during
the whole action of the piston and would be only broken again after the piston had
returned normal to be free of the contact with the contact pin. Another means of
forming an instantaneous prolonged making contact would be by providing a spring
at the top of the cylinder but projecting over, and a sufficient distance from the
wall of the cylinder that the piston in rising would make contact between the spring
and the wall of the cylinder and the contact would be prolonged practically during
the whole action of the travel of the piston; the said spring would be insulated
from the shell or case of the cylinder.
The action of the treadle is as follows:-
The normal position, as herein before mentioned, is, at the end furthest from where
it is fulcrumed, above the rail level; the first wheel of a locomotive or vehicle
depresses the treadle and also depresses the end of the transverse bar nearest the
treadle, raises the other end and with that end the piston. The passage for air in
the upward travel of the piston is free, so that the upward motion of the piston is
rapid and unobstructed, but on the return motion the bar cannot assume its normal
position until the whole of the air has passed from the lower portion of the cylinder
behind the piston to the upper portion through the valve.
normally made, upon the upward motion of the piston the contact leaves the springs
at the bottom of the cylinder and contact is broken and the result effected, whether
it be instruments released or locked, or any device actuated, briefly, any electrical
For contacts
circuit passing through the spring contacts is instantly broken.
normally broken and made through the action of the treadle, the upward motion of
With the contact

page_text: the piston makes contact, and the contact is prolonged until the piston has returned
to its normal position.
It is obvious that various alternative means may be used for the electrical make
and break contacts, but the main feature of the invention consists in the form of
pneumatic treadle applicable for railway signalling purposes for opening or closing 5
electric circuits.
Dated this 13th day of December 1893
COMPLETE SPECIFICATION.
Improvements in Treadles for Use in Railway Signalling.
I, JOHN GEORGE DIXON of 98, Norman Road, Birkby, in the County of York,
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 :-
My invention relates to an improved form of treadle for actuating an electrical
contact for any purpose in railway signalling where it is required that the passage
of a train or vehicle shall, release, lock or actuate block instruments, signals, belle,
indicators, or any devices employed for the purposes of railway signalling.
My invention consists of a lever fulcrumed at one end below rail level, the other
end being normally raised above rail level so as to be struck downwards by the
tread of the first wheel. At right angles to the said lever and attached to it is a
transverse bar or lever, the other end of the said transverse lever operates a piston
rod and piston, a valve or valves is or are provided at the end of the piston or
above the piston, in a pipe at the side of the cylinder.
There are two forms of electrical contacts which I actuate in connection with my
invention, one being a making contact, that is to say, the contact normally broken,
and in this case the contact would be a prolonged making one; the other contact is
normally made and would be broken instantaneously. To effect the latter I arrange
any known means of spring, say at the bottom of the cylinder, with a contact at
the end of the piston rod projecting through the piston. In the normal position in
the cylinder contact would be made and the rise of the piston through the deflection
of the treadle would instantaneously break the contact and the contact would
remain broken until the return of the piston in the cylinder. The other form
would be, say for example, a hole bored in the wall of the cylinder, in which is
inserted an insulated plug containing a contact pin, this pin would be normally
above the piston and upon the rise of the piston through the deflection of the
treadle would be instantaneously made but would be prolonged during the whole
action of the piston and would be only broken again after the piston had returned
normal to be free of the contact with the contact pin. Another means of forming
an instantaneous prolonged making contact would be by providing a spring at the
top of the cylinder but projecting over, and a sufficient distance from the wall of
the cylinder that the piston in rising would make contact between the spring and
the wall of the cylinder and the contact would be prolonged practically during the
whole action of the travel of the piston; the said spring would be insulated from
the shell or case of the cylinder.
In order that my invention may be better understood and more readily carried
into effect I will describe the drawings hereunto annexed.
Figure 1 is a plan of the treadle showing one form of cylinder or dash pot.
Figure 2 is a section of the dash pot shown in plan in Figure 1, arranged with a
prolonged "making contact."

page_text: Figure 3 is a section of the lower portion of the same dash pot as illustrated in
Figures 1 and 2, showing an alternative method of prolonged "making contact."
Figure 4 illustrates a section of the lower portion of the cylinder or dash pot
illustrated in Figures and 2 but arranged with an instantaneous "breaking
contact."
Figure 5 is a plan on top of my alternative dash pot, and
Figure 6 is a section of the treadle and the alternative dash pot, illustrating the
transverse lever.
The same letters refer to the same parts or substitutes therefor in the several
figures of the drawings.
With reference to Figures 1 and 2, a is a supporting sleeper which carries the
rail b, c is a treadle bar which may be of any convenient length, say 17 feet, and
it is pirotted at one of its ends below rail level, and is attached at or near its
other end to the transverse lever e by means of the connection d. The transverse
lever e is pivotted at f, the other end of the transverse lever e is connected
at g to the piston rod h, the piston ; is connected to the piston rod by the
nut is the cylinder which is open at the top but is closed and airtight at
the bottom l, m is an air valve of known construction and may be for instance
a leather flap valve. This valve is so constructed that its action allows the
piston to travel freely and unopposed on its upward stroke but its downward
motion is retarded by means of the valve m which closing prevents the free passage
of air to the upper or open end of the cylinder. o is an outside protecting shell or
case which is connected to the rod at p. The said shell or case o while acting as
a cover also acts as a counter balance weight. The piston j and cylinder kare
constructed of any convenient conducting material. In a suitable position in the
cylinder k is fixed an insulator q which consists of a plug of ebonite, porcelain or
any insulating material; a hole is first bored in k to receive, and inserted at or
near the centre of the insulator q is a conducting stop, pin or spring r, to r is.
attached a wire s. In electrical contact with k is a wire t which is fixed to k by.
any convenient means. The position of the conducting piece is such that when
the piston is at the bottom of its stroke, that is, its normal position, the contact
piece is not in contact with the piston but is situated at such a height that at
the commencement of the upward movement of the piston electrical contact would
be completed between j and r, and the circuit included in the wires s and t will be
completed and will remain completed as long as the piston j is travelling upwards
and until it has returned to its normal position when the circuit becomes broken.
It will thus be seen that as the downward travel of the piston is retarded by means
of the valve m so the contact that inakes with j (j being already in electrical
communication with k) will be prolonged correspondingly.
r
Figure 3 shows a modified arrangement of prolonged "making." contact. In this
case the electrical circuit is completed by means of a spring u which is fixed to
an insulating piece the latter being attached to k. When the piston j rises the
inner side of the piston comes in contact with the spring u and remains in
contact with u till has returned to the normal position when the circuit between
s and t will be broken.
Figure 4 shows a form of instantaneous "breaking contact," in which w is an
insulating piece fixed to l, is a conducting contact fixed to h, or the bottom nut i
as the case may be may act in lieu thereof. completes the circuit between the
contact springs or brushes y, ; these springs y andare attached to the insulating
piece w. In the normal position the pistonj is at the bottom of its cylinder k,
then is in electrical contact with y and z and consequently the circuit between.
and t is completed. When the treadle bar c is depressed by the tread of the
front wheel of a passing engine the transverse bar e is tilted so that the piston
rod h and piston ; are moved upwards, the contact of with y and : is
instantaneously broken and remains so until the return of the piston to the
normal position and makes contact with y and z. In this figure the circuit is
normally made.

page_text: Figure 5 is a plan showing the treadle, rail, transverse lever and alternative
dash pot.
Figure 6 is a section on line Y-Z' of Figure 5.
In Figures 5 and 6, the result is practically the same as that described with
reference to Figures 1 to 4 inclusive, the only difference being that a more
prolonged contact is obtained in Figure 6 and at a certain specified distance on the
return stroke of the piston the air is admitted rapidly into the cylinder and the
treadle returns normal immediately.
In these figures, a, b, c, d, e, f and g are corresponding parts to those described in
Figures 1 to 4. is the piston rod, k the cylinder, j the piston, 1 is a pipe from
the cylinder terminating in a spring valve m¹, m' is the spring, projecting from his
a tappet h having a ball or other shaped end through which a slot is made,
operating in this slot is a rod with adjusting screws ht and h³ at the ends.
A ball valve n is provided at the upper side of the cylinder. The cylinder is
enclosed.
The action is as follows:-
Normally the rod with its lower adjusting screw he is resting upon the upper
part of the valve m¹ so that the valve is normally open. On the operation of
the treadle c the transverse bar e is raised at the other side of the fulcrum; the
piston rod and piston j are moved upwards and the air is forced out of the
valve n and drawn in at the valve m. When the transverse lever and piston
have been raised to a specified distance the termination of the tappet h¹ comes
in contact with the adjusting screw and raises the lower adjusting screw h
free of the valve m² which closes by the spring m² being allowed to expand.
On the return stroke of the piston, the air not being allowed to escape freely
from either of the valves, the return movement is very much prolonged, the
escape being through leakage from the bottom to the top side of the piston; when
the piston has moved down to a predetermined distance the rod 3 is free to fall so
that the nut / presses on the top of the valve m', when air is freely admitted and
the piston completes its downward motion rapidly.
Although in this figure no electrical contacts are described it is obvious that
those described in Figures 1 to 4 inclusive are applicable in every form to the dash
pot shown in Figure 6.
Other arrangements of valves might be made; the chief point, however, of my
invention consists in arranging a dash pot substantially as described for the
purposes of making electrical contacts used in railway signalling.
It is obvious that various alternative means may be used for the electrical make
and break contacts, but the main feature of the invention consists in the form of
pneumatic treadle which when operated by the first wheel of a train or vehicle does
not return to its normal position until an interval of time has elapsed sufficient
to allow of the whole of the train having passed. Such treadles are applicable for
railway signalling purposes generally, for opening or closing electric circuits.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
•
1. In railway signalling making or breaking electrical contact by the movement
of a piston in an air cylinder, the said piston being operated by a lever connected
to a treadle fixed parallel to the rail and the treadle in its turn being depressed
by the first wheel of a passing vehicle or engine, all substantially as described
and illustrated and for the purposes specified.
2. The combination of a treadle, transverse lever, piston, air cylinder, and a
"making" electrical contact, the whole operating that the first wheel of a passing
engine depresses the said treadle and electrical contact is instantaneously made
substantially as described and for the purposes set forth.
3. The combination of a treadle, transverse lever, piston, air cylinder, and a
"breaking" electrical contact, the whole operating that the first wheel of a passing

page_text: engine depresses the said treadle and electrical contact is instantaneously broken
substantially as described and for the purposes set forth.
4. In railway signalling, the use of a piston and air cylinder for making or
breaking electrical contact, substantially in the manner described and for the
purposes specified.
5. In railway signalling, a treadle for making or breaking electrical contact,
which upon being depressed by the first wheel of a passing engine or vehicle does
not rise to contact with the other passing wheels or return to its normal position
until a predetermined interval of time has elapsed, substantially as described and
illustrated and for the purposes set forth.
6. The apparatus described and illustrated with reference to Figures 5 and 6 of
the drawings annexed for the purposes specified.
Dated this 13th day of September 1894.
JOHN P. O'DONNELL,
70 and 71, Palace Chambers, Westminster, S. W.,
Agent for the said Applicant.