Improvements in connection with Safety Bars for Railway Signalling Apparatus.
Year: 1890

page_text: Date of Application, 10th May, 1890
Complete Specification Left, 9th Feb., 1891-Accepted, 14th Mar,,
1891
PROVISIONAL SPECIFICATION.
Improvements in connection with Safety Bars for Railway
Signalling Apparatus.
We, JOIN PATRICK O'DONNELL, of 2, Great George Street, Westminster,
in the County of Middlesex, Civil Engineer, WILLIAM SMITH, of 8, Geneva
Road, Brixton, in the County of Surrey, Engineer, and ILLIUS AUGUSTUS
TIMMIS, of 2, Great George Street, Westminster, in the County of Middlesex,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
Our invention has reference to improvements in connection with safety bars for
the facing points of railways.
It is the usual practice in working the plunger and safety bar by an independent
lever for locking facing switch points to make the bar perform a circular motion
through an angle of 90 degrees that is, raise it from the lower position say on the
right up to the level of the rail and then down again to the lower position say on
the left. Briefly the heavy bar is always being moved. As is known in the art the
object of the safety bar is to prevent the switch points from being reversed during
the passage of a train or engine over the points after the signal has been given
"all clear." For such movement it is only therefore necessary that the safety bar
should be prevented from being reversed should an engine or vehicle be upon it and
when the points are plunged it is not necessary that the safety bar should be
actually worked during the process of locking the points. The principal object in
our invention is to reduce as much as possible the weight to be carried or actuated
by the facing point lock lever. It is obvious this result is of great consideration
more especially where the detecting rods are connected to the plungers as described
in O'Donnell and Stevens' Specification of Letters Patent dated September 8th
1888 Number 13002. We propose to carry out our invention in the following
manner.
The facing point safety bar is mounted alongside the rail and is worked by means
of bevel blocks acting upon blocks on the special chair, or brackets or friction rollers
fixed on the lower end of the blocks attached to the bar as set forth in the
On the
Specification of O'Donnell, Smith and Timmis Number 6262 of 1890.
under side of the bar preferably fixed near to one end is arranged a stop or pawl.
Attached to a T crank which is used for operating the bar, is a short rod and on
this rod is arranged an upward tooth or projection with a bevel on the left hand
side. There is arranged on the pawl on the under side of the bar a bevel on the
right hand side, the front of the T crank is connected to the lever for working it
and the remaining end is connected to the plunger. When the signalman operates
his lever the bevel on the tooth attached to the rod sliding on the bevel of the
downward projection or tooth raises one end of the bar upwards but does not move
at longitudinally, until the upper side of the tooth attached to the rod has passed
the pawl on the bar and got in front of it, the bar now drops, in the return motion
of operating the lever the straight face of the tooth on the rod which operates the
bar comes against the straight face of the pawl projecting from the under side of
the bar and as the rod is worked the bar is raised by its bevels sliding on the bevel
blocks on the chairs until it is high enough that the underneath tooth on the rod is
beyond the pawl upon the block, when the bar again falls to its normal position. It
is obvious of course that if anything is standing upon the bar on the return motion
of the lever the bar cannot be operated and when the lever is moved from its normal
position over, no longitudinal movement is given to the bar.
JOHN P. O'DONNELL,
Agent for the said Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in connection with Safety Bars for Railway
Signalling Apparatus.
We, Jons PATRICK O'DONNELL, of 2, Great George Street, Westminster,
in the County of Middlesex, Civil Engineer, WILLIAM SMITH, of 8, Geneva
Road, Brixton, in the County of Surrey, Engineer, and ILLIUS AUGUSTUS
Tis, of 2, Great George Street, Westminster, in the County of Middlesex,
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 :
Our invention has reference to improvements in connection with safety bars for
the facing points of railways.
It is the usual practice in working the plunger and safety bar by an independent
lever for locking the facing switchints, to make the bar perform a circular
motion through an angle of 90 degrees, that is, raise it from the lower position say
on the right up to the level of the rail and then down again to the lower position
say on the left. Briefly the heavy bar is always being moved.
in
As is known in the art the object of the safety bar is to prevent the switch
points from being reversed during the passage of a train or engine over the
points after the signal has been given all clear." For such movement it is
iherefore only necessary that the safety bar should be prevented from being
reversed should an engine or vehicle be upon it and when the points are being
plunged it is not necessary that the safety bar should be actually working during
the process of locking the points. The principal object in our invention is to reduce
as much as possible the weight to be carried or actuated by the facing point lock
lever. It is obvious that this result is of great importance more especially where
the detecting rods are connected to the plungers as described in O'Donnell & Stevens”
Specification of Letters Patent dated September 8th 1888 No. 13002.
We propose to carry out our invention in the following manner :-
The facing point safety bar is mounted alongside the rail and is worked by means
of bevel blocks acting upon blocks on the special chair or brackets, or friction
rollers fixed on the lower end of the blocks attached to the bar, as set forth in the
Specification of O'Donnell, Smith & Timmis No. 6262 of 1890.
On the under side of the bar preferably fixed near to one end is arranged a stop
or pawl. Attached to a T crank, which is used for operating the bar, is a short
rod and on this rod is arranged an upward tooth or projection with a bevel on the
left hand side. There is arranged on the pawl on the under side of the bar a
bevel on the right hand side, the front of the T crank is connected to the lever
for working it and the remaining end is connected to the plunger. When the
signalman operates his lever, the bevel on the tooth attached to the rod sliding on
the level of the downward projection or tooth on the bar, raises one end of the bar
upwards but does not move it longitudinally until the upper end of the tooth
attached to the rod has passed the pawl on the bar and got in front of it, the bar
now drops in the return motion of operating the lever the straight face of the
tooth on the rod which operates the bar comes against the straight face of the
pawl projecting from the under side of the bar and as the rod is worked the bar
is raised by its bevels sliding on the bevel blocks on the chairs until it is high
enough that the underneath tooth on the rod is beyond the pawl upon the block,
when the bar again falls to its normal position. It is obvious of course that if
anything is standing on the bar on the return motion of the lever, the bar cannot be
operated and when the lever is moved from its normal position over no longitudinal
movement is given to the bar.
In order that our invention may be more readily understood we will describe the
drawings hereunto annexed:-
Figure 1 is a side elevation of the bar in section showing the pawl on the bar aud

page_text: the tooth on the actuating rod. Figure 2 is a plan showing the bar, T crank, and
plunger. Figure 3 is a side view partly in section showing the bevel blocks on
the chairs with the stop to prevent the bar moving too high.
A is the bar; B the bevel block on the bar; C is the pawl on the bar; C¹ is
the bevel on the pawl; C³ is the straight edge of the pawl; D is the tooth_on
the actuating rod; D' is the bevel side of this tooth and D' the straight side; E is
a guide for the rod to work in; F is the T crank; G is the rod running to the
actuating lever; H is the rod from the T crank to the plunger; J is the plunger;
K is the plunger box; L is the special bevel on the chair block and K' is the stop
on this block.
Having now particularly described and ascertained the nature of our said inven-
tion, and the manner in which the same is to be performed, we declare that what we
claim is :-
1. The combination of apparatus described with reference to the drawing to
enable facing point lock levers to be operated from the normal position without
operating the facing point lock bar and of ensuring that upon the return
motion of the said lever and rod the bar is operated substantially in the manner
described.
2. In railway signalling the combination of apparatus to ensure that the facing
point lock bar is operated only in the action of withdrawing the plunger to the
unlocked position and that the facing point lock bar is not operated in the action of
locking the points, substantially in the manner described.
1001
JOHN P. O'DONNELL,
2, Great George Street, Westminster, London, S.W.,
Agent for the said Applicants.