An Improvement in Electric Switches for Currents of High Potential.
Year: 1892

page_text: Date of Application, 3rd Dec., 1892
Complete Specification Left, 2nd Sept., 1893-Accepted, 7th Oct., 1893
PROVISIONAL SPECIFICATION:
An Improvement in Electric Switches for Currents of High
Potential.
I, CHARLES JOSEPH WHARTON Electrical Engineer, c/o The Laing Wharton
& Down Construction Syndicate Limited, 38 Parliament Street, S.W. do hereby
declare the nature of this invention to be as follows:-
The improvement consists of a flapper or shutter applied to a switch in such
manner that the action of opening the switch automatically releases the flapper or
shutter, which descends with great rapidity, causing a draught of air which tends to
blow out the "arc or flame formed upon interrupting the circuit, and furthermore
the flapper completely covers the aperture through which contact is made, thereby
cutting off communication between the fixed and movable contacts of the switch.
"
Dated this 1st day of December 1892.
C. J. WHARTON.
COMPLETE SPECIFICATION.
An Improvement in Electric Switches for Currents of High
Potential.
I, CHARLES JOSEPH WHARTON, Electrical Engineer, c/o The Laing Wharton
and Down Construction Syndicate, Limited, 38 Parliament Street, S.W., 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:-
This invention has for its object an improvement in electric switches for currents
of high potential. In the use of such switches the opening of the switch is liable to
cause an arc to be established and this if permitted causes the contact surfaces to
be burnt and the apparatus to be rapidly destroyed.
According to my invention a flapper or shutter is applied to a switch in such
manner that the action of opening the switch automatically releases the flapper or
shutter which descends with great rapidity, causing a draught of air which tends to
blow out the " arc or flame formed upon interrupting the circuit, and furthermore
the flapper completely covers the aperture through which contact is made, thereby
cutting off communication between the fixed and movable contacts of the switch.
"
Figure 1 of the annexed drawings is a front view showing a simple form of switch
to which a flapper or shutter is applied, in accordance with my invention. Figure 2
is a.side view of the same. The switch here shown is a single pole switch but
the invention is also applicable to double or multiple pole switches and to other
forms.
a is a slab of slate or other suitable material, in it at a suitable distance apart
two apertures are formed. In each aperture contact surfaces bb are provided.
cc are the electric leads, they are fixed into sockets formed at the outer ends of the
conducting bars d d. Near their inner ends the conducting bars d are provided
with lugs d d by which they are fixed to the slab a. The bars d also each terminate
in two parallel comb like plates, the adjacent sides of which constitute the contact
surfaces 66 mentioned above, and which may be regarded as the terminals of the
switch.
e is a hand lever having its fulcrum at e¹ upon the slab a and is a conducting bar
mechanically fixed to the hand lever e but electrically insulated from it. The ends
of the bar fare of wedge like form and by moving the hand lever about its fulcrum
TD 21

page_text: they can be made to enter between the comb like plates on which are the contact
surfaces. The electric circuit is then closed. g is a shutter it may be of fibre or
other material, it is provided with an axis g¹ which is carried in bearings upon the
slab a.
is a spring attached at one end to the slab, and with the other pressing
upon the shutter and tending constantly to close it against the face of the slab, a
spring of any convenient form may be employed. i is a string attached to an arm
upon the axis g; by pulling this string the shutter can be raised to allow the
contact surfaces of the switch to be brought together to close the electric circuit.
Other simple means may be provided for lifting the shutter and for closing it with
a jerk.
When the hand lever is moved to open the electric circuit, the shutter is at first
forced back away from the slab a and is then suddenly released. The reaction of
the spring when the shutter becomes free moves it with rapidity towards the slab
and supposing an electric arc to have been formed the current of air which the
shutter drives before it tends to extinguish the arc. Besides the shutter by
interposing itself between the contact surfaces offers a further security against the
continuance of an arc discharge.
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 combination substantially as described with an electric switch of a flapper
or shutter liberated by the movement of the switch mechanism and driving a current
of air across the path along which an arc might be formed.
2. The combination substantially as described with an electric switch of a flapper
or shutter moving with the switch mechanism and rapidly covering one of the
terminals of the switch.
Dated this 28th day of June 1802
C. J. WHARTON.