Improvements in Facing Point Locks and Detectors.
Year: 1894

page_text: Date of Application, 23rd Oct., 1894-Accepted, 24th Nov., 1894
COMPLETE SPECIFICATION.
Improvements in Facing Point Locks and Detectors.
We, THOMAS SHEVELS of Sleetburn, Durham, Engineer, and ROBERT SIMMON
f Esh Winning, Durham, Railway Signalman, do hereby declare the nature of this
avention and in what manner the same is to be performed, to be particularly
escribed and ascertained in and by the following statement:-
Our invention has for its object to so lock the facing points of railways, that it
vould be impossible for a signalman to give signals for a contrary direction to
which his points lay, by reason of any failure or breakage of any of the operating
parts, any non-movement, or any failure of the points to properly close.
We use a box or case of suitable size and shape, two locking slides or bolts and
an operating spindle or shaft worked from the signal cabin by means of ordinary
levers, rods and cranks.
And in order that our invention may be properly understood we will proceed to
describe with reference to the accompanying drawings the manner in which the
same may be carried out, without limiting ourselves to the exact details as illustrated,
as these may be varied without altering the nature of our invention.
Fig. 1 is a plan of our improved facing point lock and detector.
Fig. 2 is a side view showing the apparatus in one of its locked positions, and
Fig. 3 is a side view showing it in its unlocked position.
D is the stretcher-bar connected to each wing of the points and is jointed at G.
This stretcher-bar has a perpendicular projection at d on the under side, where it
passes through the box, and this, projection has a width equal to the travel of the
points, and occupies half the width of the box or case A, thus leaving just space
sufficient for one or other of the locking slides or bolts B and B¹ to enter and pass
it, and so lock the points on one side or the other as they may require to be locked.
B and B are the two locking slides or bolts, one locking for the main line and the
other for the branch or siding, and each has a hinged part b and b¹ working on a
pivot F (Figs. 1, 2 and 3). These slides lie side by side in the box. The parts
and 6 overlap each other at X and are so arranged that when one of the slides is
propelled forward into the locked position it falls clear of the corresponding
overlapping part of the other slide, but when it is withdrawn into the unlocked
position (Fig. 3) it goes underneath the said overlapping part and raises it into the
position for locking as shown.
This alternation of the locking slides ensures that the points cannot be locked
twice in succession at the same side, and provides for a case of points being moved
in mistake and then put back to their first position and a breakage occurring at the
The spindle or shaft C has a transverse
second or any subsequent movement.
part cc which stretches from side to side of the box, working in guides and this
transverse part is the means by which each slide in turn is withdrawn by contact
at (Figs. 1 and 2). It also has two pivotted catches E and El to engage with a
catch such as H (Figs. 2 and 3), to propel the slide forward into its locked position.
Thus when a signalman desires to change his points he must withdraw the slide
then in locked position, and any breakage of the slide connections would leave the
slide still locking the points and he would be unable to move them in consequence
of the projecting part of the stretcher-bar being held fast by the said slide, and any
5 breakage of the point connections would leave the projecting part of the stretcher-
bar in front of the slide then in position for locking and would prevent it from
entering, and as the signal levers are locked in the ordinary manner, so as to lock
the signals controlling such points, any breakage would be detected. Also any

page_text: failure of the points to properly close would leave a portion of the projecting part
in front of the slide and it would be unable to enter.
The stretcher-bar D is jointed at G, so that if one wing of the points became
disconnected the wing so cut off would by its non-movement hinder the entrance
of the slide or bolt by reason of the projecting part not being moved in its
entirety.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
First. In connection with the facing points of railways, two automatically
alternating locking slides or bolts, one locking the main line and the other the
branch or siding.
Second. The whole arrangement and combination of parts for the aforesaid
purposes as illustrated in Figs. 1, 2 and 3 of the accompanying drawings.
THOMAS SHEVELS.
ROBERT SIMMON.