Improvements in Telephonic Switching Appliances.
Year: 1892

page_text: Date of Application, 12th Jan., 1892-Accepted, 20th Feb., 1892
COMPLETE SPECIFICATION.
Improvements in Telephonic Switching Appliances.
1, PARNELL RABBIDGE of York Street Sydney in the Colony of New South
Wales, Electrician, 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 object of this invention is the construction of a simple and effective switch
appliance, whereby the electric current may be switched from the ringing circuit,
to the speaking circuit, or vice versu for telephonic purposes.
To facilitate description of my invention I annex drawings, showing how I
accomplish my object, and I will herein refer to same as per figures and lettering
thereon.
Figures 1A, 1B, 1C, 1, 1%, represent the switch in a position which I for
convenience will consider normal.
Figures 2ª, 2ª, 20, 21, 28, represent the switch in a position which I for
convenience show in a reversed position.
A is the receptacle; B the hollow space of A, part of which is occupied by
metallic mercury m. Cand Care plugs or studs of some non-conducting
material through which one or more conducting points or surfaces a¹ and D,
and a and d face or project into B..
a¹ Da and d or surfaces a and a¹ are connected by a conductor a' either inside
the receptacle as in Figures 1, 1, 2 and 2%, or outside the receptacle as in
Figures 1, 1, 2 and 2. a a are insulated from D and d, and D and d¹
from each other. D, and a³ are electrodes.
In Figures 1 and 2, A. is considered as being made of some conducting
material and acting as a conductor, having the electrodes a attached. In
Figures 1, 1 and 2", 2%, A is also considered as being made of some conducting
material; but not as being used as a conductor in this case a¹ and D and a
and are inserted into B through C and C¹ acting in a similar manner to a¹
and D, and a and d in Figures 1, 1, 2, 2, in which A is considered as
being made of some non-conducting material preferably glass, through which a', D,
and a and face or project into B.
When the receptacle is in the position as shown in Figures 14, 1, 1, 1, 1, the
mercury m is by its own gravitation at the bottom of B, connecting a with d (or A
with d as in Figure 1). When reversing the position of the receptacle as in
Figures 24, 2, 2; 2", 2, the mercury falls to the other end of B thereby con-
necting a with D (or A with D as in Figure 2) whilst breaking the connection
between a and d (or A and d as in Figure 2). Thus it will be seen that by
altering the position of a receptacle containing a quantity of mercury and constructed
as described, the electric current may be switched from one circuit to another
through the mercury gravitating from one position to another.
As may readily be seen from the above description the shape and size of the
receptacle, the material of which it is made and the relative position and the
number of the contact surfaces or points may be varied to suit requirements,
space and convenience, but the novelty of this invention for which claim
protection is:-
The use of metallic mercury confined in a receptacle having conducting surfaces
or points insulated from each other and so arranged that the mercury may
complete an electric circuit through two conducting points or surfaces facing or
projecting into the cavity of the receptacle, at one time, and when the position
of the receptacle is altered the mercury by its own gravitation takes up another

page_text: position in the receptacle, completing another circuit, whilst breaking the circuit
previously established, substantially in the manner as described, and for the
purpose as set forth and specified.
Dated this 12th day of January 1892.
AYRTON & THOMAS,
Agents for the Applicant.