Improvements in Locks or Fastenings for Railway Carriage Doors and the like.
Year: 1896

page_text: Date of Application, 8th May, 1896--Accepted, 13th June, 1896
COMPLETE SPECIFICATION.
Improvements in Locks or Fastenings for Railway Carriage Doors
and the like.
I, DAVID MAXWELL, of the Firm of James Maxwell & Son, 17 King's Road,
Dundee, in the County of Forfar, Electrical and Mechanical Engineers and Brass-
founders, 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 relates to improvements in locks or fastenings for railway
carriage doors and the like, the object being to. provide means for securely and
automatically fastening doors and to permit of such doors being opened from
within.
And in order that ny said invention and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended five explanatory sheets of drawings in which the same reference numerals
are used to indicate corresponding parts in all the figures where shown.
Figure 1. (Sheet 1.) shows a side view of a railway carriage lock with the cover
plate removed and with the main latch 30. in the open position, while Figure 2.
gives a similar view showing the main latch in the closed position.
Figure 3. is a view looking on Figure 2. in the direction of the arrow A:
Figure 4. being a face view of the corresponding striking plate and Figure 5. a
plan of same.
The main latch 30. is formed with a boss 31. in which is a square hole 32, its
purpose being to receive the spindle of the outside handle 33. In the boss is a
recess 34. in which the inner end of a volute spring 35. is caught, the other end of
such spring being held by the stud pin or projections 36. 37. is a stop against
which the heel 38. of the latch rests when it is fully open, while 39. is a moveable
stop or lever so pivoted at 40. that the spring 41. causes its free extremity 42. to
press against the latch or to pass under it unless otherwise constrained by the
side 43. coming against the side 44. of the striking plate when the door is being
shut, that is to say the lever 39. moves in a plane normal to the plane in which the
latch 30. moves. The volute spring 35. is so wound up that the tendency of the
latch is always to seek the position shown in Figure 2, viz.: its heel 38. to press
against the stop 37. 45. is a boss on which are some teeth which gear into other
and similar teeth formed on the boss 31. of the main latch. 46. is a square hole in
such boss and in which is the spindle of the inside handle 47. the general arrange-
ment being such that the movements of the two handles synchronize. 48. is a
supplementary latch which always tends to come to the position shown in Figure 2.
unless otherwise constrained by the striking plate or by the projection 49. of the main
latch engaging with the other projection 50. of the supplementary latch. 51. is a
projection in which is a hole for the cover plate screw although its main object is
to act as a guide for the latch 48. and as a fixed resting place for the spring 52.
The striking plate is provided with an inclined plane 53. whose purpose is to press
back the main latch 30. when it is in the position shown in Figure 1. It has also
another incline plane 54. which, in a somewhat similar manner, pushes back the
supplementary latch 48. as the door is being closed. 55. is an elongated slot-
through which the main and the supplementary latches pass when in the closed
position.

page_text: A second modification of my lock is illustrated on Sheet 2. in which Figure 6. is
a side view of a lock with the .cover plate removed and with the main latch 30. in
the open position, while Figure 7. shows a similar view with the main latch in the
closed position. Figure 8. is a view looking on Figure 6. in the direction of the
arrow B. and Figure 9. is a sectional elevation at Z. Z. (Figure 7.). Figure 10. is
a plan of the lock casing and Figure 11. is an isometric view of the moveable stop
or lever 39.
In this modification the main latch 30. rests against the bottom of the slicket in
the lock casing when in the closed position, that is to say the part at 56. acts as a
stop. The action of the lever 39. is similar to that already described in my first
modification.
A third modification of my lock is illustrated on Sheet 3. in which Figure 12. is
a side view of a lock with the cover plate removed and with the main latch 30. in
the open position, while Figure 13. shows a similar view with the main latch in the
closed position. Figure 14. is a view looking on Figure 13. in the direction of the
arrow C, and Figure 15. is a part plan showing the point of the sliding bolt 48,
while Figure 16. is a face view of the striking plate, Figure 17. being the plan of
same.
In this modification the main latch rests against the bottom of the slicket at 56,
as in my second modification, and I use instead of the lever, a sliding bolt 48.
having a projection 50. for engaging with the latch 30. when it is in the open
position, in this way jamming it in such a manner that it is not released until the
bolt 48, is pushed back by the striking plate.
A fourth modification of my lock is illustrated on Sheet 4. in which Figure 18.
is a side view of a lock with the cover plate removed and with the main latch 30.
in the open position, while Figure 19. shows a similar view with the main latch in
the closed position. Figure 20. is a face view of the striking plate and Figure 21.
is a plan of same.
In this modification the main latch is operated much as in my second modification,
the difference being in the manner of operating the catch 48. This catch is pivoted
at 57. and is raised by the action of the groove 59. on the pivot 48. when the door
is being shut. It may also be raised by the corner 49. acting on the projection 50.
as the latch is turned. 58. is a spring whose force tends to keep such catch 48. in
its lowest position.
A fifth modification of my lock is illustrated on Sheet 5. in which Figure 22. is
side view of a lock with the cover plate removed and with the latch 30. in the
open position, while Figure 23. shows a similar view with the latch in the closed
position. Figure 24. is a view looking on Figure 23. in the direction of the
arrow D.
This modification is similar to that shown on Sheet 1. with the exception that it
does not have the supplementary latch.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
(1) In self closing locks, the combination and arrangement of parts consisting of
the main latch 30, outside handle 33, volute spring 35, stop 37, lever 39, inside
handle 47, supplementary latch 48, and the suitable striking plate, all substantially
as described and illustrated on Sheet I.
(2) In self closing locks, the combination and arrangement of parts consisting of
the main latch 30, outside handle 33, volute spring 35, stop 56, lever 39, and inside
handle 47, all substantially as described and illustrated on Sheet 2.
(3) In self closing locks, the combination and arrangement of parts consisting of
the main latch 30, outside handle 33, volute spring 35, stop 56, inside handle 47,
sliding bolt 48, and the suitable striking plate, all substantially as described and
illustrated on Sheet 3.
(4) In self closing locks, the combination and arrangement of parts consisting of.

page_text: the main latch 30, outside handle 33, volute spring 35, stop 56, inside handle 47,
catch 48, and the suitable striking plate, all substantially as described and illustrated
on Sheet 4.
(5) In self closing locks, the combination and arrangement of parts consisting of
the latch 30, outside handle 33, volute spring 35, stop 37, lever 39, inside handle 47,.
all substantially as described and illustrated on Sheet 5.
Dated this 6th day of May 1896.
GEO. C. DOUGLAS & Co.,
41 Reform Street, Dundee, Agents for Applicant.