Improvements in Interlocking Apparatus for Railway Point and Signal Levers.
Year: 1893

page_text: Date of Application, 21st Jan., 1893-Accepted, 4th Mar., 1893
COMPLETE
OPTRATION.
Improvements in Interlocking Apparatus for Railway Point and
Signal Levers.
I, SAMUEL TELFORD DUTTON, of Marl Bank, in the City and County of
Worcester, Civil 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 locking apparatus for railway points and signals, which
I construct with a view to simplicity of parts and the reduction of friction in the
gearing and also to shorten the draught upon the tappets.
In order that my invention may be better understood and more readily carried
into effect I will proceed to describe the drawings hereunto annexed, in which
Figure 1 is a side elevation showing a lever in its normal position, and the means
by which the locking mechanism is operated.
Figure 2 is a front elevation of Figure 1.
Figure 3 is a plan of the locking box or trough, showing the interlocking tappets,
their notches, and the locks.
Figure 4 is an enlarged view of the fulcrum of the lever showing the slot in the
projection beyond the fulcrum, in which the pin connecting the links to the tappet
operates.
Figure 5 is a plan of Figure 4.
The same letters refer to the same parts or substitutes therfor in the several
figures of the drawings.
a is the main lever which may be a signal, point, point-lock, or other operating
lever for signalling purposes. is the catch handle at the back of the lever a
c is the rod connecting the catch handle to the drop box d; e is the continuation
of the catch handle below the segment of the locking frame; is the cross bar
centred at g to the lever a, and connected at one end to the continuation of the
catch rod c. The other end of the cross bar is connected to a pair of links h, the
links are connected in their turn by means of the pin i (which pin i moves in a
slot j) to the pair of links k, the links & in their turn are connected to the inter-
locking tappet. m is the locking box or trough through which the tappets 1³
moves and in which the locking is effected; n is a lock in the locking trough;
a notch in the tappet l, this is a locking notch; is a notch also in the tappet ?,
but is a releasing notch. The lock n is shown in the bottom of the locking trough,
Figure 3.
The operation of my invention is as follows:-
is
When the catch handle is raised the cross bar fis operated that a downward
movement is given to the links_h, the pin i is moved to the bottom of the slot j,
and the links k and the tappet is thereby operated so that the locking of con-
flicting levers is effected.
On referring to Figure 3 it will be seen that the tappet in the downward
movement which it takes presents a straight surface to the lock ; the notch l
having moved downward, thereby holding the lock n into the notch in the next
tappet, the lever connected to the tappet is thereby locked.
When now the movement of the lever a takes place, the projection o being
bolted about the fulcrum to the lever a, is moved downward so that the links k are
moved into the position that the pin i takes the position (in dotted lines Figure 4)
of p; this gives a very slight backward movement to the tappet l. It should be
understood that in the first movement of the tappet by the raising of the catch
handle, that the tappet is moved some short distance beyond the required move-
ment to effect the locking, so that when the slight backward movement takes place

page_text: of the pin i assuming the position of p (dotted lines Figure 4), that there is still
latitude allowed for the perfect locking to have taken place. On the catch handle
being now replaced in the pulled over position of the lever a further forward move-
ment is given to the tappet by an upward movement of the pin i assuming the
position (in dotted lines Figure 4). This moves the tappet / sufficiently forward
so that the release notch, as in Figure 3, comes opposite a lock such as r, which
lock would be connected to any lever which would be normally locked and should
be released by the forward movement of the tappet / connected to the lever a.
"
The return motion of the lever a to its normal position is practically a reverse
movement of the various parts until they assume their normal position as in
Figure 1.
The slot j beyond the fulcrum is curved to a radius equal in length to the links k.
The curve of the slot j regulates the progressive movement of the tappet so that
at any part of the stroke of the lever the rate of motion of the tappet 7 coincides
with that of the catch rod c-e.
It is obvious that my invention is applicable to the ordinary lever and spring
catch handle or to ordinary segmental plates with front and back notches, and to
what is known as ordinary tappet locking.
I make no claim to the principle of tappet locking generally, nor do I claim
the principle of operating tappets by means of a catch rod, but what I do
claim is :-
:-
1. In interlocking apparatus for railway point and signal levers, the use of a
cross bar fulcrumed to the lever, one end connected to the extension of the
catch rod and the other to the links connected to a pin moving in the slot j,
the links being connected to the said pin and the tappet itself connected to
the said link, the whole operating substantially as described and illustrated for the
purposes herein set forth.
2. In interlocking apparatus for railway point and signal levers, the provision of
a projection beyond the fulcrum, provided with a slot through which the locking
tappets are operated in the movement of the lever, substantially as described and
illustrated and for the purposes herein set forth.
3. In railway signalling, the combination of apparatus for the purposes of
interlocking levers, substantially as described and illustrated and for the purposes
herein set forth.
Dated this 21st day of January 1893.
JOHN P. O'DONNELL,
70 & 71, Palace Chambers, Westminster, London, S.W.,
Agent for the said Applicant.