Improvements in Railway-block Interlocking Instruments.
Year: 1898

page_text: Date of Application, 31st Aug., 1898-Accepted, 15th Oct., 1898
COMPLETE SPECIFICATION.
Improvements in Railway-block Interlocking Instruments.
I, SIDNEY PRESCOTT WOOD, of Semaphore Works, Newport, Melbourne, in the
Colony of Victoria, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement: -
In railway-block interlocking instruments as at present constructed, it has been
found in practice that unless there is accurate adjustment, it is possible by operat-
ing the plunger to give a line-clear or other electrical signal, either to make
contact twice or to lock the plunger without making contact at all.
Now this invention has for object to obviate this disadvantage and in instru-
ments according thereto it is impossible for the contact to be made until, by the
act of plunging, the falling-bar has arrived in such a position that after contact
has been made the plunger or plunger-bar must be locked.
For this purpose according thereto instruments are constructed as will now be
described with reference to the accompanying illustrative drawings, in which
Figs. 1, 2, and 3 show respectively in front elevation, in side elevation, and in
plan, sufficient of such an apparatus to illustrate the nature of the invention.
The falling-bar 1 carries at its upper end, and insulated from it, a contact-
piece 2 against which constantly bears a spring 3 carried by, and insulated from,
a bracket 4 secured to a suitable portion of the case of the instrument and in
electrical connexion with the line-wire 5. In a position normally not vertically
under the contact-piece 2, a spring contact-piece 6 is secured to the upper end of
a lever 7 which is mounted to turn freely on a stud 8 fixed to the case of the
instrument and has secured to it the battery-wire 9. The lower end of the lever 7
is connected by a link 10 to the plunger-bar 11, shown in the form of a bell
crank lever. On being pressed against the plunger-bar 11, the plunger 12, by
means of the link 10 and the lever 7, brings the spring contact-piece 6 vertically
under the contact-piece 2 carried by the falling-bar 1, and when the plunger-
bar 11 has pushed clear of its support 13 the catch 14, which is pivoted to the
falling-bar at 15 and is normally kept against a stop 16 by a spring 17, the
the contact-piece 2 falls upon the
falling-bar 1 drops and
piece 6 and thereby completes the circuit. The return of the plunger-
bar 11 to its normal position, which is effected by spring-power in
the ordinary way, withdraws the contact-piece 6 from under the contact-
piece 2, whereby contact is broken; the falling-bar 1 then completes
its travel under the action of gravity and thereby prevents the plunger-bar 11
from being again actuated until the bar 1 has been returned to its normal
position in the ordinary way. As the contact-piece 6 is in the position shown,
and not vertically over the contact-piece 2 when the falling bar is in its lowest
position, the falling-bar can be raised without bringing the contact-pieces into
contact.
contact-

page_text: Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is: :-
1. A railway-block interlocking instrument adapted to prevent the operation
of the plunger to give an electrical signal, from making contact twice or locking
the plunger without making contact at all, substantially as hereinbefore described.
2. A railway-block interlocking instrument adapted to make electrical contacts
by the descent of a falling-bar, substantially as hereinbefore described.
3. A railway-block interlocking instrument of the kind referred to in Claim 2,
in which the contact-piece to be struck by the contact-piece to be operated by
the descent of the falling-bar is so mounted and connected that it will be
normally out of the path of the second mentioned contact-piece and will be brought
therein by the act of plunging and restored to its normal position by the return
of the plunger-bar, substantially as therein before described.
4. Railway block interlocking instruments constructed, arranged, and operating
substantially as hereinbefore described with reference to and shown in the accom-
panying drawings.