Improvements in or connected with Bases and Covers for Electrio Switches and Fuses.
Year: 1894

page_text: Date of Application, 27th Feb., 1894-Accepted, 23rd June, 1894
Improvements in or connected with Bases and Covers for Electrio
Switches and Fuses.
I, FRIEDRICH WILHELM BUSCH, of Ludenscheid, in the Empire of Germany,
Gentleman, 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 :-
The covers of electric switches and fuses are ordinarily attached to the bases by
means of a screw-thread. This device is open to two main drawbacks. One is that as
such covers and bases are usually made of porcelain or china it is extremely
difficult to make satisfactory screw-threads, and the cost of such apparatus is
increased proportionately. Another drawback is that there is a great expenditure
of time and trouble in screwing on and off the covers, and the screw-threads are
frequently injured by stripping or jamming.
My invention has for its object the overcoming of these drawbacks, and in
carrying it into effect, instead of employing a screw-thread by which to attach the
cover to the base, I employ what is known as a bayonet joint.
My invention is illustrated in the accompanying sheet of drawings, of which
Figures 1 to 4 illustrate one form of my invention.
Figure 1 is a view of a cover seen from below, and Figure 2 a transverse section
of the same.
Figure 3 is a plan view of the base of a fuse, and Figure 4 is a section of the
same with the cover placed in position.
It will be seen that the projections in the cover fit into the vertical slots of the
base and that then by turning the cover through an angle of say 90 degrees the
projections are moved through the horizontal slots and the cover is by this simple
action locked in position.
It will be seen that the projections on the cover just described are integral with
the same, but this arrangement is not essential. Thus in Figure 5 the projection
hereinbefore mentioned is replaced by an L-shaped piece attached to the cover by
a screw. In this case the lower part of the said L-shaped piece serves exactly the
same function as do the projections shown in Figure 1.
Figure 6 is another form of my invention in which the projection, instead of
being integral with the cover as in the case first hereinbefore mentioned, consists
of a stud or pin screwed or jammed into a recess or orifice in the cover.
In the cases herein before described I have spoken of the projections as being on
the cover and the slots in which such projections engage as being on the base. This
however is not necessary, for it is obvious that the projections might be upon the
base and the slots on the cover.
Having now particularly described and ascertained the nature of iny said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The improvement in or connected with bases and covers for electric switches
and fuses which consists in the employment of a bayonet joint substantially as and
for the purpose set forth.
2. The improvement in or connected with bases and covers for electric switches
and fuses which consists in the form of bayonet joint set forth with reference to

page_text: 3. The improvement in or connected with bases and covers for electric_switches
and fuses which consists in the bayonet joint projection set forth with reference to
Figure 5.
4. The improvement in or connected with bases and covers for electric_switches
and fuses which consists in the bayonet joint projection set forth with reference to
.Figure 6.
Dated this 27th der of Feb 1908
J. G. LORRAIN, M. Inst. E.E., &c.
Chartered Patent Agent.