Improvements in Self-locking Double-bolt Carriage and other Door Locks.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Self-locking Double-bolt Carriage and other
Door Locks.
I, LUCIEN ALPHONSE LEGROS, of 57, Brook Green, London, W., Engineer, do
hereby declare the nature of this invention to be as follows; -
This invention relates more particularly to that class of locks or fastenings
used for railway carriage doors but is also applicable to other doors requiring a
self-locking device.
The object of my invention is the construction of a lock having two distinct
bolts, so arranged that upon the door of the carriage being slammed or closed
both bolts will automatically enter the striking plate and the handle be turned
to a horizontal position. Upon turning the handle backwards to open the door,
the two bolts will be withdrawn.
In carrying out my invention I propose to arrange a sliding spring bolt or latch
above the main bolt which may be pivotted with its handle in the usual manner.
The lower or underside of this sliding bolt or latch is provided with two dependent
horns or projections which engage with the front or inner face respectively of the
main bolt, when the latter is turned within the lock casing. The inner end of
the main bolt around the square opening for the spindle is shaped somewhat
eccentrically and has two indentations situated on the edge at nearly a quarter
of a circle distance from each other.
Between the main bolt and the upper sliding latch is a lever pivotted at its
upper end and furnished with a roller at its lower end which bears upon the inner
end of the main bolt. Immediately behind this pivotted lever is a laminated
spring which actuates the same and causes the roller to bear upon the boss or inner
face of the main bolt.
In operation, upon the handle being turned backwards to open the door the
main bolt turns with it until its inner face comes into contact with the inner
of the two dependent projections or horns on the sliding bolt which is then carried
backwards until both bolts are withdrawn from the striking-plate or staple. As
soon as the handle is released the main bolt is driven in an outward direction
by the pressure of the spring until the roller upon the lever engages with the
first of the indentations upon the boss of the main bolt when it is at once arrested.
In this position the upper or sliding latch will have resumed its normal position
and the lock is ready for closing. Upon slamming the door the sliding bolt is
driven inwards by coming into contact with the striking plate and its outer
dependent projection or horn forced against the outer or front face of the main
bolt causing this latter to turn in a backward direction until the roller is raised
from out of the indentation and the door properly closed. When this occurs the
upper spring latch will be driven outward by the action of its spring and the main
bolt also driven forward or outward by the pressure of the roller upon its eccentric
boss until the former enters the second indentation. In this application the main
bolt is held in the open or closed position by the pressure of the roller within the

page_text: indentations upon the boss of the bolt. In a modification of the above I may
dispense with one or both of these indentations and form a bevelled face upon
the underside of the inner projection of the sliding bolt or latch which engages
with a corresponding shoulder formed upon the inner face of the main bolt when
this latter is turned back or in the open position, the arrangement being such that
the two faces are caused to abut at a point on the posterior face of the main bolt,
thereby securely locking the bolt from any further movement. Upon the door
being slammed, the sliding bolt or latch will be driven inwards as before and
the stop withdrawn from the bolt, which is then free to turn in an outward
direction under the impulse of the spring exerted through the lever. By this
arrangement it will be impossible for the main bolt to be accidently turned when
the door is open.
Improvements in Self-locking Double-bolt Carriage and other
Door Locks.
I, LUCIEN ALPHONSE LEGROS, of 57, Brook Green, London, W., Engineer, do
hereby declare the nature of this invention and what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
This invention relates more particularly to that class of locks or fastenings
used for railway carriage doors, but is also applicable to other doors requiring a
self-locking device. The object of my invention is the construction of a lock
having two distinct bolts, so arranged that upon the door of the carriage being
slammed or closed, both bolts will automatically enter the striking plate, and the
handle will be turned to a horizontal position. Upon turning the handle back-
wards to open the door, the two bolts will be withdrawn.
In carrying out my invention I propose to arrange a sliding spring bolt or
latch above the main bolt which may be pivotted with its handle in the usual
manner.
The lower or underside of this sliding bolt or latch is provided with two depen-
dent horns or projections which engage with the front and the inner face respec-
tively of the main bolt, when the latter is turned within the lock casing. The
inner end of the main bolt around the square opening for the spindle shaped
somewhat eccentrically and has two indentations situated on the edge at nearly
a quarter of a circle distance from each other.
Between the main bolt and the upper sliding latch is a lever pivotted at its
upper end and furnished with a roller at its lower end which bears upon the
inner end of the main bolt. Immediately behind this pivotted lever is a laminated
spring which actuates the same and causes the roller to bear upon the boss or
inner face of the main bolt, see Figure 1 of the accompanying sheet of drawings.
In operation upon the handle being turned backwards to open the door the
main bolt A turns with it until its inner face a comes into contact with the inner
of the two dependent projections or horns 6 on the sliding bolt B which is then
carried backwards until both bolts are withdrawn from the striking-plate or
staple. As soon as the handle is released the main bolt is driven in an outward

page_text: direction for a small portion of its downward stroke by the pressure of the spring
until the roller d upon the lever D engages with the first of the indentations
upon the boss E of the main bolt when it is at once arrested, the bolt A being
thus maintained approximately upright within the lock casing as shewn in Fig. 1.
In this position the upper or sliding latch will have resumed its normal position
and the lock is ready for closing. Upon slamming the door the sliding bolt 1
is driven inwards by coming into contact with the striking plate (not shewn on
drawings) and its outer dependent projection or horn 6 forced against the outer
or front face a¹ of the main boit causing this latter to turn or tilt in a backward
direction from its normal (approximately upright) position until the roller dis
raised from out of the indentation e and the door properly closed. When this
occurs the upper spring latch B will be driven outward by the action of its spring I
and the main bolt A also driven forward or outward by the pressure of the roller
upon its eccentric boss E the main bolt continuing to revolve until the roller d
enters the second indentation e¹. In this application the main bolt is held in
the open or closed position by the pressure of the roller within the indentations e e¹
upon the boss of the bolt, and the lock is fired by the sliding latch B striking
the striking plate.
"
23
In a modification of the above, see Figure 2, I may dispense with one or
both of these indentations and form a bevelled face upon the underside of the
inner projection b of the sliding bolt or latch B which engages with a correspond-
ing shoulder a formed upon the inner face of the main bolt A when this latter is
turned back or in the open position, the arrangement being such that the two
faces are caused to abut at a point on the posterior face of the main bolt, thereby
securely locking the bolt from any further movement. Upon the door being
slammed, the sliding bolt or latch B will be driven inwards as before and the
stop or projection b withdrawn from the shoulder a on the bolt which is then free
to turn in an outward direction under the impulse of the spring C exerted through
the lever D. The two bolts A and B may, if desired, be simultaneously turned
back by leaving a sufficient projection G on the main bolt which is driven back
on impact with the striking plate in such case (see Figure 3) the outer dependent
projection on the sliding latch B may be omitted. By this arrangement it wil
be impossible for the main bolt to be accidentally turned when the door is opened.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
(1). In a lock having a revolving and a sliding bolt, the provision on the sliding
bolt of two dependent horns bb₁ for the purposes and substantially as described,
and illustrated on Figures 1 and 2.
(2). In a lock having a revolving and a sliding bolt, securing the revolving bolt
in the open position by the engagement of a shoulder a upon the revolving bolt
with a projection 6 on the sliding bolt, substantially as described and illustrated
on Figures 2 and 3.
Dated this Eleventh day of April 1899.
For the Applicant,
GEDGE & FEENY,
Chartered Patent Agents, 60, Queen Victoria Street, London, E.C.