Improvements in Electrical Switches.
Year: 1896

page_text: Date of Application, 28th Aug., 1896
Complete Specification Left, 21st May, 1897-Accepted, 26th June, 1897
Improvements in Electrical Switches.
I HERBERT GRACE RICHARDSON of Ash Lea, Corubrook Park Road,
Manchester, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My said invention relates to an improved construction of switch or contact
appliance for electric lamps and the like purposes.
In its essential features my said invention consists of a swinging lever or cam to
which two pushers or buttons are connected so that whon one pusher is pressed in
the other is caused to protrude. The cam in one position engages with and presses
down a plunger in such a manner as to cause it to make contact with one of the
terminals. In the other position the cam allows the plunger to rise under the
action of a spring thus causing the contact to be rapidly broken.
Dated this 25th day of August. 1896.
E. T. WHITELOW, A.M. Inst. C.E.,
70 Deansgate, Manchester, Agent for the Applicant.
HERBERT GRACE RICHARDSON of Ash Lea, Cornbrook Park Road,
Manchester, Electrical Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described aud
ascertained in and by the following statement :-
My said invention relates to au improved construction of switch for contact
appliances electric lamps and the like purposes.
DESCRIPTION OF DRAWINGS.
Fig. 1 is a side elevation of a switch made in accordance with my said invention
with the contact made.
Fig. 2 is a similar elevation showing the contact broken.
Fig. 3 is an end elevation with the contact made.
lo all the figures the same letters refer to the same parts.
In the drawings my invention is shown as applied to a lamp holder of the
ordinary construction in which a a' are the terminals or contact pieces for an
incandescent lamp, b is a block or mounting of suitable insulating material, c c are
the wires from the electric supply. The terminal a' is in metallic contact with
the plate d. The terminal a is in inetallic contact with the plate d' which extenda
upwards and is permanently connected to the wire c. The wire o' is attached to
the metal plate or mounting e.
On the plate e is a cam which can oscillate about its axis'.

page_text: When in the position shown in Fig. 1 the notched lower end of the cam engages
with and keeps pressed down a metal plunger 9 and so makes contact with the
plate d. The plunger 9 is normally pressed upwards by a spring 9 preferably
of spiral form so that when the cam is caused to assume the position shown
in Fig. 2 the plunger g rises and the metallic contact with the plate dis
broken.
In one form of my said invention the cam is operated by pushers' attached
to the extreme ends of the cam f and extending through the casing. When
contact is made the pusher A protrudes. To break contact the pusher is
pushed in when the pusher h will pass outwards and assume the position shown in
Fig. 2. Thus in either position of the cam f only one pusher is out and whether
to light or to extinguish the lamp it is only necessary to push in the protruding
pusher. The heads of the pushers may be provided with knobs or buttons if
desired.
The head of the plunger g is made conical so that directly it is released from
the notch the inclined surface of the hoad bears against the circular face of the
cam and by tho action of the spring g' accelerates the oscillation of the cam and
thus breaks contact very quickly.
In lieu of the pushers h h a central handle extending outwards through the
casing and provided with a head A' may be used for turning the cam f as indicated
by dotted lines in Fig. 3.
The point of the plunger 9 is preferably of conical form with a split end taking
into a conical depression in the plate d when contact is made.
Although shown in its application to the pendant lamp holder of an incandescent
lamp, it is to be understood that my said invention is also applicable to other
electrical appliances such as wall switches and the like.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declaro that what I
claim is.―
1. An appliance for making and breaking electric contact substantially as
hereinbefore described and shown.
2. The combination of an oscillating cam a metallic plunger ga spring g
for normally keeping the same out of contact and a metallic contact plate d
substantially as and for the purpose hereinbefore described and set forth.
3. The combination of an oscillating cam falternately protruding pushers h
a spring-impelled plunger 9 and a contact plate d substantially as and for the
purpose set forth and shown.
Dated this 18th day of May 1897
E. T. WHITELOW, A.M. Inst. C.E.,
70 Deansgate, Manchester, Agent for the Applicant.