Improvements in Electrical Switches.
Year: 1888

page_text: Date of Application, 26th Nov., 1888
Complete Specification Left, 26th Aug., 1889-Accepted, 26th Feb., 1890
PROVISIONAL SPECIFICATION.
Improvements in Electrical Switches.
FREDERICK LAWRENCE RAWSON, Electrical Engineer of 11, Queen Victoria Street,
London, E.C. and WILLIAM WHITE Electrical Engineer of the same address, do
hereby declare the nature of this invention to be as follows:-
:-
The present Invention relates to improvements in Electrical Switches.
We form in an Electrical Switch, the centre metal flange or washer fitting over the
centre bush with a lug at one side which stands up at a suitable angle to the switch
base and forms a stud or support against which the fixed ends of the throw off springs
press. This flange may be stamped or formed out of sheet metal by suitable tools
which may be arranged so as to bend it over at the top in any suitable form so as to
prevent the springs from slipping off it; or we may cast the flange and lug in one or
more pieces; or we may fasten a stud in any suitable way into into the flange or
washer as a support for the springs. By one or other of these methods we prevent
the breaking loose of the stud which is a common occurrence with the ordinary method
of fastening it directly into the insulating material of the switch base. The centre
flange or washer may be prevented from turning round by running a steady pin
through it into the base or by a lug formed upon it which enters a suitably disposed
hole in the base.
We form the nut which holds the brush onto the square on the centre pin of an
oblong rectangular shape of the same width as the brush and we screw it down till it
lies directly over the brush; the two pins against one of which the free ends of the
springs press are then screwed through the brush into the oblong nut securely
fastening the whole fitting together.
At the side of the brush we attach a spring so arranged that it intervenes between
the brush and the stop pin when the brush flies off and so prevents the jar. This
spring may be conveniently formed of a stamping of such a shape that a side piece on
it of the same size as the above mentioned oblong nut is turned over and suitably
fastened between this nut and the brush to ensure a firm attachment of the spring
to the brush.
Alternatively to or as well as fixing a spring on the brush we may place a buffer
piece on the stop pin which may be the stud holding the loop ends of the springs ;
this buffer consists of an L shaped piece of metal with or without a rubber stud and
it may be stamped and the shorter arm of which forms a nut on the stop pin and the
longer arm of which stands at a suitable angle in front of the stop pin and spring
loops, thus forming the buffer.
Another part of our invention consists of a new attachment to the switch handle to
allow of a free and quick break of contact under the influence of the springs
independently of the handle. This attachment is a washer suitably formed of sheet
metal with two lugs left in it at opposite ends of a diameter and turned down at a
suitable angle to the plane of the washer; it is fixed to the under side of the handle
fitting which turns freely on the upper part of the switch centre pin and the two lugs
lie one on each side of the oblong nut and brush. These lugs are made of such a
width that the brush has a suitable amount of free rotation independently of the
handle so that when turned by the handle to a suitable point on the contact plates it
flies off by the action of the springs only, thus preventing any possibility of the brush
emaining in such a position as to allow the formation of an arc.
The switch is conveniently covered with a metal case of a cylindrical form with a
uitably ornamented top through which the handle passes, the cover being screwed on
o the base or held on by a bayonet catch. We attach a metal moulding round the
ottom which may serve to cover the bayonet lock or other fastening.

page_text: In order to fasten the pins, upon which the bayonet joint locks securely into the
base, we make a small saw cut at the end of the pin that enters the hole which is
drilled in the base and we insert a small wedge at the bottom of the saw cut. On the
pin being driven firmly into the hole the wedge increases the size of the pin at the
bottom of the hole and thus prevents it getting loose.
:
COMPLETE SPECIFICATION.
Improvements in Electrical Switches.
FREDERICK LAWRENCE RAWSON Electrical Engineer of 11 Queen Victoria Street
London E.C. and WILLIAM WHITE Electrical Engineer of the same address, do hereby
declare the nature of this invention & in what manner the same is to be performed,
to be particularly described & ascertained in & by the following statement :-
: The present invention relates to improvements in Electrical Switches.
Referring to the drawings Figs. 1 II III & XIV we form in an electrical switch
the centre metal flange or washer "A" fitting over the centre bush "B" with a
lug "C" at one side which stands up at a suitable angle to the switch base and forms
a stud or support against which the fixed ends of the throw off springs "D" press.
This flange may be stamped or formed out of sheet metal by suitable tools which may
be arranged so as to bend it over at the top "C" in any suitable form so as to prevent
the springs slipping off it; or we may cast the flange or lug in one or more pieces ;
or we may fasten a stud in any suitable way into the flange or washer as a support
for the springs. By one or other of these methods we prevent the breaking loose of
the stud which is a common occurrence with the ordinary method of fastening it
directly into the insulating material of the switch base. The centre flange or washer
may be prevented from turning round by running a steady pin "E" through it
into the base or by a lug formed upon it which enters a suitably disposed hole in
the base.
"
We form the nut "F figs. I XII XIII which holds the brush on to the square on
the centre pin as shown in Fig. XIII and we screw it down till it lies directly over
the brush; the two pins "HH" fig. I against one of which the free ends of the
springs press are then screwed through the brush "G" into the nut "F" securely
fastening the whole fitting together. At the side of the brush we attach a spring "I"
fig. XIV so arranged that it intervenes between the brush "G" & the stop pin "K"
when the brush flies off and so prevents the jar. The spring see figs. X & XI may be
conveniently formed of a stamping of such a shape that a side piece on it of the
same size as the above mentioned nut "F" is turned over and suitably fastened
between this nut and the brush to ensure a firm attachment of the spring to the
brush. Alternatively to or, as well as fixing a spring on the brush we may place a
buffer piece "L" on the stop pin "K" which may be the stud holding the loop ends
of the springs "D" this buffer consists of an L shaped piece of metal with or without
a rubber stud as shewn in Figs. VI & VII and it may be stamped and the shorter arm
of which forms a nut on the stop pin and the longer arm of which stands at a
suitable angle in front of the stop pin and spring loops, thus forming the buffer.
Another part of our invention consists of a new attachment to the switch handle M
to allow of a free & quick break of contact under the influence of the springs
independently of the handle. This attachment see figs. IV & V is a washer "N"
suitably formed of sheet metal with two lugs "PP" left in it at opposite ends of a
diameter and turned down at a suitable angle to the plane of the washer; it is
fixed to the under side of the handle fitting M fig. I which turns freely round the
upper part of the centre pin Q and the two lugs lie one on each side of the nut "F"
and brush "G." The lugs are made of such width that the brush has a suitable
amount of free rotation independently of the handle so that when it is turned by the
pressure of one lug of the handle M to suitable points on the contact plates. "R. R".
fig. XIV it flies off by the action of the springs only being free to move without a

page_text: further rotation of the handle M thus preventing any possibility of the brush
remaining in such a position as to allow the formation of an arc & the brush breaks
contact much faster than if it were controlled by the hand moving the handle M.
The switch is conveniently covered with a metal case "S" fig. I of a cylindrical form
with a suitably ornamented top through which the handle passes, the cover being
screwed on to the base or held on by a bayonet catch.
In order to fasten the pins "TT" fig. XIV upon which the bayonet joint locks
securely into the base, we make a small saw cut at the end of the pin that enters
the hole which is drilled in the base see figs. VIII & IX and we insert a small
wedge at the bottom of the saw cut. On the pin being driven firmly into the hole
the wedge increases the size of the pin at the bottom of the whole & thus prevents
its getting loose.
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 :
1. In an electrical switch the use of a bush and lug or washer & lug formed in one
or more pieces. for the purposes set forth substantially as described & shown in
Figs. I, II, III.
2. In an electrical switch the use of a buffer spring for the purposes set forth.
3. In an electrical switch the combination of a switch base and cover pins secured
substantially as described.
4. In a switch the use of a nut as shewn in figs. XII & XIII in combination with a
switch bar and spindle substantially as described.
5 An electrical switch substantially as described and shewn in figures 1 & XIV.