An Improved Switch for Making and Breaking Contact.
Year: 1889

page_text: Date of Application, 30th Sept., 1889
Complete Specification Left, 28th June, 1890-Accepted, 2nd Aug., 1890
PROVISIONAL SPECIFICATION.
An Improved Switch for Making and Breaking Contact.
I, JOHN MACINTOSH MACKAY MUNRO of 136 Bothwell Street Glasgow in the
County of Lanark, North Britain, Electrical Engineer do hereby declare the nature
of this invention to be as follows:-
:-
My Invention relates to an improved switch for making and breaking contact, and
consists of a round contact plug attached to two insulated buttons projecting on either
side of the switch case. When one or other of the buttons is pressed, the contact plug
is either pushed between or withdrawn from contact with two springs. When the
two springs are connected by the plug the circuit is completed and when the springs
are disconnected the circuit is broken. The switch case is so placed that when the
plug is released from contact with the two springs it falls away by its own weight.
A glass front is provided to the case so that if any undue sparking takes place it
may be detected.
The form given to the springs and supporting blocks is such that the whole can be
made very strong and still occupy a small space which makes the switch very
compact and also permits of a fusible cut out being placed within the switch when
required.
Dated this 28th day of Santamber 1889
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.
COMPLETE SPECIFICATION.
An Improved Switch for Making and Breaking Contact.
I, JOHN MACINTOSH MACKAY MUNRO, of 136 Bothwell Street, Glasgow, in the
County of Lanark, North Britain, Electrical 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 relates to an improved switch for making and breaking contact, and
consists of a round contact plug attached to two insulated buttons projecting on either
side of the switch case. When one or other of the buttons is pressed the contact plug
is either pushed between or withdrawn from contact with two springs. When the
two springs are connected by the plug the circuit is completed, and when the springs
are disconnected the circuit is broken. The switch case is so placed that when the
plug is released from contact with the two springs it falls away by its own weight.
A glass front is usually provided to the case, so that if any undue sparking takes
place it may be detected.
The form given to the springs and supporting blocks is such that the whole can be
made very strong, and still occupy a small space, which makes the switch very
compact, and also permits of a fusible cut out being placed within the switch when
required.
In order that my Invention may be properly understood and readily carried into
effect I have hereunto appended an explanatory sheet of drawings, in the several
Figures of which corresponding parts are marked with the same letters of
reference.
Figure 1 is an elevation of the switch when the circuit is broken, and Figure 2. is
an elevation when the circuit is made. The metal springs a a' are attached to the
metal pieces b. The rod dd, moveable freely up and down through holes in the
case, is composed of an upper insulating part d, a metal plug e at the middle, and a
lower insulating part d'. A detached metal piece ff¹ is provided in the case.
The

page_text: wires of the circuit are connected to the switch at band, and the fusible cut out
connects ¹ and f¹. When the rod d d is at its lowest position, as shown in Figure 1,
the circuit is broken, as there is no connection between a and a¹. To complete the
circuit the rod d d' is pushed up until the plug e comes in contact with the springs a a¹.
The rod is held in this position by the pressure of the springs on the plug. When
the plug is released from contact with the springs it falls away by its own weight,
and thus any danger of sparking is avoided. The rod d d can be turned round its
own axis. Thus, when in the position shown in Figure 2, both the plug and springs
can be cleaned at any time by rubbing together to ensure good contact.
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. The switch, substantially as described and illustrated.
2. In a switch, the round rod, having a round metal plug at the middle for com-
pleting the circuit, as described.
n
'
1000
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.