Improvements in Detonators for Railway Fog Signalling.
Year: 1898

page_text: Date of Application, 7th May, 1898-Accepted, 11th June, 1898
COMPLETE SPECIFICATION.
Improvements in Detonators for Railway Fog Signalling.
I, JOHN GEORGE DIXON, of "Don Villa," Penistone, in the County of Yorks,
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;-
-
My invention has reference to improvements in detonators for railway fog
signalling and the like, whereby said detonators are rendered more perfectly water-
tight than those hitherto in use.
My improved detonator consists of four pieces of dished metal, (preferably tin)
which are stamped out, and the usual nipples or pillars for the percussion caps;
these four parts comprise an outer and inner bottom or lower portion and an outer
and inner top or cover, and the chief feature of my present invention is 'the special
form of inner cover enclosing the explosive compound and the percussion caps.
This special inner cover is of concavo-convex form, the outside or top being convex
and surrounded by a rim or vertical flange said rim or flange being deeper or higher
than those of both the outer and inner lower portions of the detonator. The usual
strip of lead (or other suitable metal) for attaching the detonator to the rail is
placed on the top of the detonator instead of as heretofore on the bottom and is
attached thereto by being run through a couple of slots formed in the top or outside
cover of the detonator and may be also soldered thereto if desired.
In order that my invention may be better understood and more readily carried
into effect I will now describe it with reference to the accompanying drawing in
which-
Figure 1 is a plan of my improved detonator, Figure 2 being a cross section on
line A-B Figure 1, of the cupped or dished tins which when fitted together one
within the other form my improved detonator. Figure 3 shows the detonator as
placed upon the rail.
The same letters refer to the same parts in the several figures of the drawings.
a is the outside lower portion or bottom of the detonator into which fits the inner
lower portion in which the explosive compound is placed, the usual percussion
caps and their supporting pillars passing through holes in the bottom of b. c is
the special form of inner cover or cap which fits in the portion and encloses the
explosive and caps, the rim or flange c¹ (Figure 2) of this inner cover being higher
or deeper than those of the parts a and b. d is the outer cover which fits within the
rim or flange c, the slots being formed therein by stamping. c is the lead
strip which is held in position by being run through slots d¹ and soldered in
addition if desired. The rims or flanges of the parts a, b and c (Figure 2) when all
the parts comprising the detonator are fitted together, are bent inwards.
It will be seen that should any water get inside the outer cover it cannot
possibly reach the explosive in b as to do so it would have to rise above the rim or
flange c' of the inner cover c and it would then be outside the detonator.
By placing the lead strip e, for attaching the detonator to the rail, on the top
instead of on the bottom, an even surface is obtained for resting on the rail.

page_text: 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 detonators for railway fog signalling, an inner cover or cap of concavo-
convex form as c (Figure 2) said inner cover having a rim or flange which is
higher or deeper than the flanges of the lower portions or tins in which it fits,
substantially as set forth for the purpose specified.
2. In detonators for railway fog signalling, the combination of lower portions or
tins as a and b (Figure 2) which contain the explosive, an inner cover or cap as c
and an outer cover or cap with slots or passages to which is attached the lead strip
or other means for clipping the detonator to the rail, substantially as herein set
forth with reference to the accompanying drawings.
3. My improved detonator for railway fog signalling substantially as herein
described with reference to the accompanying drawings.
Dated this Seventh day of May 1898
JOHN P. O'DONNELL, Fel. Chart. Inst. P.A.,
Agent for the said Applicant,
70 & 71, Palace Chambers, Westminster, S.W.