Improvements in Electrical Switches.
Year: 1887

page_text: Date of Application, 20th Dec., 1887
Complete Specification Left, 20th Sept., 1888
Complete Specification Accepted, 26th Oct., 1888
Improvements in Electrical Switches.
We, FREDERICK LAWRENCE RAWSON, of 11 Queen Victoria Street, in the City of
London, Electrical Engineer, and WILLIAM WHITE, of 40 Ranelagh Road, Harlesden,
in the County of Middlesex, Instrument maker, do hereby declare the nature of
this invention to be as follows:-
Our invention relates to improvements in electrical switches, and has for its chief
object the construction of a switch making simultaneously quadruple contacts by
the mutual elastic reaction of duplicate or multiple switch arms and combined with
a spring device to ensure sudden and rapid break of contact when desired.
One form of our apparatus is constructed as follows:-
Upon a vertical spindle, capable of rotation around its axis, is fixed a pair or pairs
of switch arms.
These switch arms are conveniently formed of a series of arched
bent plates or strips, which thereby afford a certain amount of elastic spring when
the under faces of their bent ends are forced upon the contact pieces; or rigid switch
arms may be employed to the same effect, with mutually reacting elastic washers
behind them. Each switch arm is provided with a pair of contact pieces, which
present bevelled edges towards the switch arm as it enters thereon, and the mutual
reaction of the elastic switch arms ensures considerable pressure upon the contact
pieces whilst they are in contact.
In order to produce a sudden break of contact between the switch arm and the
contact pieces, one method is to apply two springs, which are conveniently situated on
the face of the switch, and may be of a V shape, one extremity of the said V resting
against fixed pins on the face of the switch. Two pins, projecting from the under
side of the switch arm, press against the other side of the V springs, as the switch
arm rotates, thus producing resilience on the part of the said springs, as the switch
is turned to make electrical contact. When the switch arms are making contact, the
spring resilience presses upon the switch arm practically at dead centre, and thus has
no power to produce rotation. As however the switch arm or arms are turned back
to break contact, the action of the springs tends to produce rotation in the direction to
break contact. The switch arm is checked in a suitable position between contacts by

page_text: non conducting stops, and is then properly situated for broken contact.
A convenient
method for adjusting the pair of contact arms is, for one to make contact on strips
upon the upper face. of the non conducting body of the switch, and the other to make
contact with a reverse pressure on strips upon the under side of the switch. The
pressures of the two elastic switch arms thus react upon one another to ensure good
contact pressure.
We may however employ such a pair of switch arms placed in the
reverse position to one another with contact faces above and below the said switch
arms which thus lie between the said contacts.
To produce the necessary rotation of the switch arm, it is advisable to let the
contact arms turn round rapidly when they are on the point of breaking contact,
without the hand turning it on and off, acting as a break, and to do this we may
conveniently employ a key in the form of a thumb piece provided with two projecting
pins and a central hole, which dropping over a central pin of the switch axis, enables
the pins of the thumb piece to engage in other slotted holes in the head of the switch
axis and thus to produce the desired rotation.
We may conveniently construct the springs out of a series of suitably bent V shaped
steel wires, which may be combined in a desired number to provide
a spring of
suitable strength, but do not limit our apparatus to a spring of this nature.
Cut-outs can be placed in both circuits in series with the contact pieces. The
cover may be screwed on or fastened with a bayonet joint with screws to tighten it
down.
The switch can also be arranged as a single switch, both arms being in multiple are,
so that the second arm can be made to break after the first arm has ceased to make
contact the second arm in this case is preferably made of carbon and can have a
resistance in series with it.
T
لبيت
1
1031
FELL & WILDING,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.

page_text: We, FREDERICK LAWRENCE RAWSON, of 11 Queen Victoria Street, in the City of
London, Electrical Engineer, and WILLIAM WHITE, of 40 Ranelagh Road, Harlesden,
in the County of Middlesex, Instrument maker, 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 :-
Our invention relates to improvements in electrical switches, and has for its chief
object the construction of a switch making simultaneously quadruple contacts by the
mutual elastic reaction of duplicate or multiple switch arms and combined with a
spring device to ensure sudden and rapid break of contact when desired.
In order that our invention may be the better understood we now proceed to
describe one form of our apparatus in relation to the drawings hereunto annexed
reference being had to the letters and figures marked thereon.
Figure 1 is a sectional elevation of our improved switch.
Figure 2 is a plan of the same.
Upon a vertical spindle A capable of rotation around its axis, is fixed a pair or pairs
of insulated switch arms B. These switch arms are conveniently formed of a series of
arched bent plates or strips, which thereby afford a certain amount of elastic spring
when the under faces of their bent ends are forced upon the contact pieces Ů; or
rigid switch arms re-acting may be employed to the same effect, with mutually reacting
elastic washers behind them. Each switch arm is provided with a pair of contact
pieces C which present bevelled edges towards the switch arm as it enters thereon,
and the mutual reaction of the elastic switch arms ensures considerable pressure upon
the contact pieces whilst they are in contact.
In order to produce a sudden break of contact between the switch arm and the
contact pieces, one method is to apply two springs D which are conveniently situated
on the face of the switch and may be of a V shape, one extremity of the said V
resting against fixed pins on the face of the switch. Two pins E projecting from
the under side of the switch arm B press against the other side of the V springs, as the
switch arm rotates, thus producing resilience on the part of the said springs, as
the switch is turned to make electrical contact. When the switch arms B are making
contact, the spring resilience presses upon the switch arm practically at dead centre,
and thus has no power to produce rotation. As however the switch arm or arms are
turned back to break contact, the action of the springs tends to produce rotation in
the direction to break contact. The switch arm B is checked in a suitable position
between contacts of non-conducting stops F, and is then properly situated for broken
contact. A convenient method for adjusting the pair of contact arms is as shown, for
one to make contact on strips upon the upper face of the non-conducting body G of
the switch, and the other to make contact with a reverse pressure on strips upon the
under side of the switch. The pressures of the two elastic switch arms thus react
one upon another to ensure good contact pressure. We may however employ such a
pair of switch arms placed in the reverse position to one another with contact faces
above and below the said switch arms which thus lie between the said contacts.

page_text: To produce the necessary rotation of the switch arm it is advisable to let the contact
arms turn round rapidly when they are on the point of breaking contact, without the
hand turning it on and off acting as a break and to do this we may conveniently
employ a key H in the form of a thumb piece provided with two projecting pins h
and a central hole, which fitting loosely over a central pin K of the switch axis,
enables the pins of the thumb piece H to engage in other slotted holes L in the head
of the switch axis and thus to produce the desired rotation.
We may conveniently construct the springs out of a series of suitably bent
V shaped steel wires which may be combined in a desired number to provide a spring
of suitable strength but do not limit our apparatus to a spring of this nature.
Cut-outs can be placed in both circuits in series with the contact pieces. The cover
may be secured on or fastened with a bayonet joint with screws to tighten it down.
The switch can also be arranged as a single switch both arms being in multiple arc,
so that the second arm can be made to break after the first arm has ceased to make
contact the second arm in this case is preferably made of carbon and can have a
resistance in series with it.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1st. In an electric switch the combination on a single axis of two or more elastic
switch arms reacting against one another so as to produce mutual contact pressure
upon their respective contact pieces, substantially as described.
2nd. In an electric switch the combination of such duplicate or multiple elastic
switch arms with a spring or springs producing a quick automatic break from the
contact pieces in conjunction with an operating thumbs piece or hand lever permitting
independent movement of the switch arms to break, substantially as described.
3rd. In an electric switch the construction of the thumb piece or hand lever,
consisting of a pair of projecting pins outside a central hole, fitting loosely over the
switch axis, the pins engaging in are slots in the head of the said axis, substantially
as and for the purposes described.
4th. In an electric switch the combination of two reacting switch arms both being
in multiple are, the second arm being made to break contact after the first arm has
ceased to make contact substantially as described.
Dated this 20th day of September.
TELL & WILDING,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.