A New or Improved Automatic Safety Latch for the Doors of Railway Vehicles.
Year: 1897

page_text: Date of Application, 16th Sept., 1897--Accepted, 11th Dec., 1897
COMPLETE SPECIFICATION.
A New or Improved Automatic Safety Latch for the Doors of
Railway Vehicles.
We, ERNEST RAYMOND, Mechanic, of 43 Rue Léopold and NICOLAS COLLETTE,
Mechanical Engineer of 37 Rue du Beau-Mur both in Liege, in the Kingdom of
Belgium, 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:-
This invention refers to a safety latch, and relates to that type of fastening in
which the latch itself is in the form of a pivotted arm, the latter when fastened
taking behind a fixed part, the invention particularly referring to such latches
closing automatically upon the door being shut, all sustantially as hereafter
described.
The following description refers to Figs. 1 to 6 of the accompanying drawings.
The box which contains the mechanisin. is divided into two parts A and B by
means of a partition C (see Fig. 5). The part B Fig. 1, contains only the operating
spring R, and certain parts hereafter mentioned which spring R has for object
to depress the latch L when the mechanism within. the part A is in such position
as hereinafter described, to allow of that movement.
For this purpose the spring R acts upon a pin D in a piece with the cam E
which latter is keyed on the axle of the latch L. The latch L has a knob or
handle L' for use when required.
Fig. 2 which shews the latch in the vertical position, that is to say in the opened
position, also shews the parts within the chamber A. The pawl F has for object
to prevent the latch L from moving beyond the vertical position. The pawl G
has for object to maintain the latch in that position in opposition to the action
of the spring R, which latter tends to depress the same. The tumbler bolt K
and the slide H Fig. 5 have for object as hereinafter described, to raise the
paw Gat the proper time in such a manner as to disengage the
cam and to allow the spring R to depress the latch L. The socket.
or retaining piece I (Figs. 3, 4 and 6) behind which the latch L takes, is formed
with an inclined surface P, in front of which moves the point of the tumbler bolt K
when the door is closed again.
At Fig. 6, and at the dotted position K Fig. 4, the position of the bolt K is
shewn at the moment at which it meets the inclined surface P. In order to pass
(see Fig. 4) from the position K' into the position K" (which is the position
when closed), the bolt K must slide along the inclined surface P, that is to say,
the centre of its vertical section must describe the curved line indicated in Fig. 4,
by a dotted arrow.
It will be seen that the bolt K rises first along the inclined surface, then as soon
as it arrives in front of the vertical plane N which terminates the socket or retain-
ing piece, it moves down again, being pushed by the spring of the pawl G and
the slide H. This motion has caused the bolt K to be lifted & forced into the lock
case. But in its ascending movement along the inclined surface, the bolt has
raised the slide H and the pawl G, and it has therefore disengaged the cam E,
.

page_text: and the spring R has depressed the latch L, at the very moment when the door
was entering its frame-opening. The latch is thus automatically closed.
Although not forming any essential feature of the invention, S is a projecting
guide on the lock edge taking over the part I Fig. 4. and in some cases the part I*
is rebated at 1 Fig. 4. to take into recessed face B*, Fig. 3. and may form a stop
for the lock.
It will be seen that in the position of closure, the bolt K by reason of its being
constructed in two parts, a hollow head sliding on a stem, has moved into the
interior of the box. By reason of this position of the bolt K when closed, the
bolt K will not move back along the inclined surface when the door is opened.
The bolt will slide along the vertical surface N. Therefore when the latch L
shall have been placed in the vertical position, the door will be capable of being
opened without raising the bolt K, and consequently without allowing the spring R
to depress the latch, the latch L being retained by the pawl G.
Fig. 2 shews clearly that if by a false movement the latch should fall into the
lower vertical position the parts of the mechanism are arranged in such a manner
that the latch will always be capable of being brought rack by hand into the
top vertical position, or even into the position of closure.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1. The arrangement and construction of a latch such as that herein before
described, which allows of opening doors in exactly the same manner as hitherto,
but which closes automatically as soon as the door is pushed back into its frame-
opening.
2. In automatic safety latches for the doors of railway vehicles, the general
arrangement and combination of parts, substantially as and for the purposes set
forth.
Dated this 15th day of September 1897