Improvements in or relating to Electrical Switches.
Year: 1899

page_text: Date of Application, 2nd Oct., 1899
Complete Specification Left, 30th June, 1900-Accepted, 8th Sept., 1900
PROVIDIONAL DI
Improvements in or relating to Electrical Switches.
I, SIDNEY ALFRED HUNTER, of 18, Albert Mansions, Albert Bridge Road,
Battersea Park, in the County of Surrey, Electrical Engineer, do hereby declare
the nature of this invention to be as follows:
وو
This invention relates to electrical switches and has special reference to switches
of the "Tumler
The
type although its application is not limited thereto.
object of this invention is the provision of a switch which while simple in con-
struction and compact in size shall have a long and quick break, and at the same
time owing to the arrangement of the levers, shall have an easy action when
in use.
In switches according to this invention the contact levers are pivotted near
one edge of the base while the contact blocks or terminals are situated near the
other edge and are separated by a block of insulating material preferably forming
part of the base itself. The contact lever which may consist of two blades rigidly
connected together by a yoke-piece is so arranged that the blades make contact
with the outside of the contact blocks.
"
The contact blades are raised to open the circuit by the action of a spring
which, when the switch is in the on position is compressed between the base
and the contact levers or a bridge piece connecting them.
The switch is closed by the movement of a lever carried upon the block which
separates the contact blocks, such lever acting upon a bar, projection or roller
carried by the contact levers, and being provided with a recess into which the
roller enters when the switch is quite closed. The position of the bar, projection
or roller relatively to the pivot of the contact blades, and the form of the lower
part of the pivotted lever is such that the switch may be closed with a perfectly
easy action. The recess in the bottom portion of the pivotted lever, provides a
definite position for the lever when the switch is closed and prevents the liability
of the switch to be accidentally opened. Means are provided whereby the motion
of the lever in "opening" the switch shall if necessary overcome the friction
between the contact levers and the contact blocks and allow the spring to act
freely.
2:
The following is a description by way of example of one construction of a
single pole switch according to this invention.
The base, of insulating material, preferably porcelain, is provided with two
blocks or projections upon its upper surface one higher than the other and situated
opposite to each other. To the smaller block are pivotted the contact-levers,
which are formed of an H-shaped piece of metal the free ends of which make
rubbing contact, when the switch is closed, with metal contact-blocks situated
one on each side of the larger block and provided with terminals for the attach-
ment of the leads. A spring is placed between the yoke of the H-shaped contact-
levers and the base, such spring tending always to keep the free ends of the
levers up i.e. away from the contact-blocks.
A cross bar carried between the two limbs of the H-shaped contact-levers is
provided with a roller free to turn upon it, and either of insulating material or

page_text: insulated from the levers. A loop, say of wire, is also carried by the cross
bar.
Upon the larger block or projection on the base a lever is pivotally mounted,
its top end passing through a central opening in a cover as in the ordinary
"Tumler" switch. The lower arm of this pivotted lever is shaped as a hook and
the back of it is so shaped that when the lever is moved in one direction it bears
against the roller upon the cross-bar and forces the contact-levers down against
the action of the spring thus closing the switch. A slight recess is formed in
the bottom portion of the pivotted lever into which the roller enters when the
switch is closed.
To open the switch the lever is moved slightly so as to disengage the roller
from the recess, when the action of the spring at once raises the contact-levers,
the further motion of the pivotted lever being caused by the roller pressing
against its shaped lower portion.
The hook upon the lower end of the pivotted lever engages with the loop
carried by the cross bar, and, in the event of the friction between the contacts
being too great to allow of the spring breaking circuit, the contact-levers are
raised by the pivotted lever until the spring comes into action.
The pivotted lever may be mounted directly upon the block in a space made
for that purpose when the base is manufactured, or it may be carried in a metal
mounting secured to the block.
All the detachable fittings upon the switches according to this invention are
secured to the base from the front or upper surface, thus obviating the necessity
of fastening them by screws entering from the back.
Dated this 2nd day of D1000
Improvements in or relating to Electrical Switches.
I, SIDNEY ALFRED HUNTER, Electrical Engineer, of 26, Shaftesbury Avenue,
in the County of London, formerly of 18, Albert Mansions, Albert Bridge Road,
Battersea Park, in the County of Surrey, 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:-
The
This invention relates to electrical switches and has special reference to switches
of the "Tumler" type although its application is not limited thereto.
cbject of this invention is the provision of a switch which while simple in con-
struction and compact in size shall have a long and quick break, and at the same
time owing to the arrangement of the levers, shall have an easy action when
in use.
In switches according to this invention the contact levers are pivotted near
one edge of the base while the contact blocks or terminals are situated near the
other edge and are separated by a block of insulating material preferably forming
part of the base itself, and serving to support a handle or lever. The contact
lever which may consist of two blades rigidly connected together by a yoke piece
is so arranged that the blades make contact with the outside of the contact blocks.
The contact blades are raised to open the circuit by, the action of a spring
which, when the switch is in the
on position is compressed between the base
and the contact levers or a bridge piece connecting them.
"
The switch is closed by the movement of a lever carried upon the block which

page_text: separates the contact blocks, such lever acting upon a bar, projection or roller
carried by the contact levers, and being provided with a recess into which the
roller enters when the switch is quite closed. The position of the bar, projection
or roller relatively to the pivot of the contact blades, and the form of the lower
part of the pivotted lever is such that the switch may be closed with a perfectly
easy action. The point of contact between the lever and the cross member of
the contact blades shifts relatively to the lever, and not as is usually the case
relatively to the contact blades or tongues. The recess in the bottom portion
of the pivotted lever, provides a definite position for the lever when the switch is
closed and prevents the liability of the switch to be accidentally opened. Means
are provided whereby the motion of the lever in opening the switch shall
if necessary overcome the friction between the contact levers and the contact
blocks and allow the spring to act freely.
In the accompanying drawings, which illustrate by way of example
struction of a single pole switch according to this invention,
Figure 1 is a plan,
Figure 2 is a central vertical section,
Figure 3 is a side elevation with a portion broken away,
one con-
Figure 4 is a view similar to Figure 3 showing the switch in another position,
and
Figure 5 is a plan of a portion of the switch.
In all the figures the cover of the switch is removed for the sake of clearness.
Like letters indicate like parts throughout the drawings.
A is a base of insulating material, preferably porcelain provided with two
blocks or projections A A2, the block A being higher than the projection A2
and situated upon the opposite side of the top surface of the base A. Through
a hole in the block A² a pin B passes forming a pivot for contact blades B.
These blades are situated one on either side of the block A and are joined by
a connecting strip 132. The blades B and the connecting strip B32 form an H-shaped
contact-piece which may conveniently be stamped in one piece, the blades B
being bent into shape afterwards.
The blades B are mechanically connected by a pin B, which is, however,
insulated from them by means of collets 13ª. A roller B³ is carried by the pin
between the blades B and between the ends of this roller and the inside ends of
the collets 13 the extremities of a wire loop B are loosely secured. The pin and
its collets etc. are kept in place by means of nuts 137, or the ends of the pin may
be turned or rivetted over. The H-shaped contact-piece with its accessories is
shown separately in Figure 5.
Upon each side of the larger projection A' a contact block C is provided secured
to the base A by means of screws C. The free ends of the blades B make
contact when the switch is closed with the outside surfaces of these contact blocks.
The usual means are provided as at C2 for the attachment of wires to the contact
blocks.
Upon the top of the block A¹ a plate D is mounted. It carries a screwed
portion D on to which a switch cover may be placed in the usual way, and is
formed with a strap 12, the end of which engages with a recess A at the back
of the block A¹ The plate D is fastened to the base A and block A¹ by means
of a screw D3 which is passed up through a recessed hole A in the bottom of
the base A. and engages with the plate. For the purpose of insulating the recess
in which the head of the screw 1 lies is filled with an insulating wax or com-
position after the screw is in place.
Pivotally mounted on the plate D as at D is a lever E provided at its upper
end with a knob or handle E. The lower back portion of this lever E is in
contact with the roller 15 when the switch is open as shown in Figure 2, and a
function of the lever E is to depress the contact blades B against the action of a
spring F, which operates between the strip B2 and the base A, 'and thus bring
them into connection with the contact blocks C. In order that the descent of

page_text: the contact blades B, before they reach the contact blocks C, shall be made
quickly the portion E2 of the lever E, which is acting at that stage of the opera-
tion, is given a curve which lies approximately in the same general direction as
the longitudinal centre line of the lever E, but the adjacent portion, that 'is
the lowest part of the back of the lever E which completes the downward move-
ment of the contact blades B, is rounded so as to be but slightly eccentric to
the pivot D, and thus the blades B, when in contact with the blocks C can be
moved with ease into their lowest position. This position is made a positive
one by providing at the bottom curved portion of the lever E a slight recess E³
which engages with the roller 15 when the switch is closed.
The shape of the pivotted lever E, besides causing the first part of the down-
ward motion of the contact blades B to be quick, will of course allow the
corresponding upward motion, that is the latter portion of the upstroke, to be
accomplished quickly, thus making the break a rapid one.
To open the switch the lever E is moved slightly so as to disengage the roller B³
from the recess E when the action of the spring should at once raise the contact
blades B the further motion of the pivotted lever being caused by the roller
pressing against its shaped lower portion. The upward movement of the blades B,
while nor lly caused by the action of the spring F which has been compressed
by the closing of the switch does not depend entirely upon such action, for a
hook is formed upon the lever E and engages with the loop B6 carried by the
pin B. Thus in the event of the friction between the contacts being too great
to allow the spring breaking the circuit, the contact blades B will be raised
positively by the action of the pivotted lever until the spring comes into action.
Although the pivotted lever E has been described as mounted upon the plate I)
attached to the block A¹, it is to be understood that it may, if desired, be mounted
directly upon the block A' in a space provided for that purpose when the base
is manufactured.
Again if desired the plate D, instead of being secured from the bottom as by
the screw D³, may be fastened by screws which pass into the block A¹ from the
top. In this latter case all the detachable fittings would be secured to the base
from the front or upper surface, thus obviating the necessity of fastening them
by screws entering from the back.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A switch having contact blocks separated by the insulating projection A'
which also forms an insulating support on which a handle or lever is fixed, and
contact blades such as B engaging with the outside surfaces of the blocks sub-
stantially as described.
2. In a switch a pivotted lever such as E E² E³ arranged and operating sub-
stantially as described.
3. In a switch the combination with a pivotted lever such as E E2 E3 of a
contact-piece provided with a cross member substantially as described.
4. In a switch the combination with a contact-piece B B2 with or without a
loop B of a pivotted lever E E E E substantially as described.
5. The complete switch substantially as described and illustrated in the accom-
panying drawings.
Dated this 28th day of June 1900.
SIDNEY A. HUNTER.
Boult, Wade, & Kilburn,
Agents for the Applicant.