Improvements in Electrical Switches.
Year: 1895

page_text: Date of Application, 22nd Feb., 1895
Complete Specification Left, 22nd Nov., 1895-Accepted, 28th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in Electrical Switches.
We, REGINALD WILMOT HAYES NEWINGTON, of 16 Killieser Avenue,
Streatham Hill in the County of Surrey, Electrical Engineer, and RICHARD
HEWLETT, of 31 Essex Street, Strand, in the County of London, Gentleman, do
hereby declare the nature of this invention to be as follows:-
Our invention relates to improvements in electrical switches of any form of known
construction and consists in the adaptation to such switches of a coned or pyramidal
contact face engaging into a corresponding coned or veed recess between the fixed
contacts and travelling arm or arms of such electrical switches.
To carry out our invention we may arrange the fixed contacts and travelling arm
or arins of an electrical switch in any convenient or known manner to effect any
desired series of contacts or breaks of electrical circuits, but assuming that the arm
We arrange
or arms of the said switch rotate about a fixed axis of rotation.
the fixed contacts divided and insulated in any convenient manner in the form of a
We arrange
pyramidal or coned ring and in the arm or arms travelling thereon.
a similar coned or veed recess accurately fitting the said pyramidal ring or vice-
versa, the pyramidal tongue may be upon the travelling arm or arms and the
corresponding coned or veed circular recess may be formed on the fixed contacts.
Such coned or pyramidal contact faces may be easily ground together to form
accurate contacts, and are little liable to spoil effective electrical contact by the
springing or twisting of the arms.
A further advantage of such contact faces is that as wear proceeds they still
more accurately grind down upon one another, the face of contact also is greater
in a given diameter than is the case with two plain flat faces of contact and the
actual pressure of contact is greater by reason of the wedge forn of the contact
surfaces, for any given spring pressure than would be the case with flat faces at
right angles to such spring pressure.
Dated this 22nd day of Febru 1895
FELL & WILDING,
1 Queen Victoria Street, E.C., Agents for the Applicants.
We, REGINALD WILMOT HAYES NEWINGTON, of 16 Killieser Avenue, ·
Streatham Hill, in the County of Surrey, Electrical Engineer, and RICHARD
HEWLETT, of 31 Essex Street, Strand, the County of London, 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:
..:
'xx
Our invention relates to improvements in electrical switches of any form of known
construction and consists in the adaptation to such switches of a contact face of
recessed, coned, or pyramidical section engaging into a corresponding recess of

page_text: pyramidical coned for veed section, between the fixed contacts, and the travelling arni
or arms of such electrical switches.
And in order that our invention may be the better understood we now proceed to
describe the same in relation to the drawings hereto annexed and to the figures and
letters marked thereon.
Figure 1 is a plan and part sectional elevation of a known form of rotating switch
arm and contacts, with our special contact faces adapted thereto.
Figures 2, 3 and 4 are detached sectional elevations of obvious modifications in
form of our special contact faces between switch arm and fixed contacts.
To carry our invention into effect, we may arrange the fixed contacts and
travelling arm or arms of an electrical switch in any convenient or known manner,
to effect any desired series of contacts or breaks of electrical circuits, and we only
show the arrangement of switch arm and fixed contacts in Fig. 1 as a simple and
convenient example of a known switch arm. A is the switch arm, moved by the
insulated handle B around a spring-pressed and insulated axis C. Fixed insulated
contacts D are arranged as segments of a circle about the axis C. In Figure 1 we
show, the fixed contacts D, with a contact face of pyramidical section, in rubbing
contact with corresponding "veed recesses E, on the switch arm A.
"
In Figure 2 we show the obvious converse, of a recessed "reed" face on the fixed
contacts D, in rubbing contact with a projection of pyramidical section on the switch
arm A.
In Figures 3 and 4, we show the fixed contacts D making elastic rubbing contact
with the switch arm A in a radial direction to the axis C, the faces of pyramidical
and recessed "veed" section of contact being shown in obvious converse position in
the two Figures 3 and 4 respectively.
In both of these latter cases, the fixed contact is provided with a face D' held by
a pin F to the fixed contact D, and sliding thereon, radially to the axis C, by the
pressure of a spring G, to make elastic rubbing contact on the switch arm.
Such contact faces of coned or pyramidical section may be easily ground together
to form accurate contacts, and are little liable to spoil effective electrical contact by
the springing or twisting of the arms.
A further advantage of such contact faces is, that as wear proceeds, they still
more accurately grind down upon one another.
The face of contact also is greater in a given diameter, than is the case with two
plain flat faces of contact, and the pressure of contact is greater by reason of the
wedge form of the contact surfaces for any given spring pressure, than would be
the case with flat faces at right angles to such spring pressure.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1st. In an electrical switch the arrangement of the contact faces between any
fixed contacts and a movable arm or arms, in the form of a projection of coned,
"veed," or pyramidical section upon the arm, and corresponding recess, upon the
fixed contact, or vice versu, substantially as described.
2nd. In an electrical switch, a sliding spring-pressed piece on the fixed contact,
with projecting face of coned "veed," or pyramidical section, making contact
radially to axis, of the switch arm, upon a corresponding recess in the end of the
switch arm, or vice versa, substantially as described.
3rd. The construction of contact faces in an electrical switch, substantially as
described herewith, and illustrated in the drawings annexed hereto.
Dated this 22nd day of November 1805
FELL & WILDING,
1 Queen Victoria Street, London, E.C., Agents for the Applicants.