Year: 1887

page_text: Date of Application, 8th Feb., 1887
Complete Left, 8th Nov., 1887
Complete Accepted, 9th Dec., 1887
We ALFRED FREDERICK DEWAR of 47 Warner Road Camberwell New Road,
Telegraph Instrument Maker and FREDERICK WILSON of 5 Hampton Avenue,
Brisbane Street, Camberwell Green, Engineer, both in the County of Surrey do
hereby declare the nature of this invention to be as follows:-
This invention relates to the construction of a novel and simple switch suitable for
use in electric lighting, electric signalling and the like, the object of the invention
being to provide a switch which cannot be placed in any intermediate position and
which is automatically locked in its contact and insulated positions.
In constructing our improved switch we employ a spindle, the outer end being
provided with a handle, the said spindle carrying contact arms the ends of which are
turned at right angles. The lower end of the spindle is provided with inclined
surfaces or cams adapted to fit into or work upon or against corresponding inclined
surfaces or cams on a fixed boss. The inclined surfaces of the spindle are held against.
the inclined surfaces of the boss by means of a suitable spring or springs. When in
the contact position that is to say in the position for closing the circuit the ends of the
contact arms press against suitable contact springs. If the spindle be now turned by
means of its handle one quarter of a revolution the inclined surfaces of the spindle
sliding against the inclined surfaces of the boss will cause the spindle to be raised
until the inclined surfaces reach their limit when the spring will move the spindle
down into the next or insulating position the spring locking the parts in this position
until they are again moved into the contact position by turning the spindle in the
opposite direction to that hereinbefore described.
We have described inclined surfaces or cams as giving good results but it will be
obvious that we can employ a pin and slot arrangement or a right and left handed screw
arrangement.
The parts are mounted on a base plate of any suitable insulating material and the
whole may be enclosed within a suitable casing, the handle projecting outside.
G. F. REDFERN
4, South Street, Finsbury, London,
Agent for the Applicants.

page_text: We, ALFRED FREDERICK DEWAR, of 47, Warner Road, Camberwell New Road,
Telegraph Instrument Maker, and FREDERICK WILSON, of 5, Hampton Avenue,
Brisbane Street, Camberwell Green, Engineer, both 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:
Our invention relates to the construction of a novel and simple switch suitable for
use in electric lighting, electric signalling, and the like, the object of the invention
being to provide a switch which cannot be placed at any intermediate position between
its contact and insulated positions and which is automatically locked in these positions,
and to this end it comprises the improvements hereinafter described.
In the accompanying drawings
Figure 1 is a plan of a switch constructed according to my invention, the cover
being removed, and
Figure 2 is an elevation of the same.
Figure 3 is a vertical section on the line xx, figure 1, the cover being shown in
position.
Figures 4, 5, 6 are views similar to figures 1, 2 and 3 respectively, but illustrating a
modification of my invention.
a is the base of the switch and b is a cover or cap for enclosing the mechanism of
the switch; c is a spindle, the outer end of which is provided with a handle d and
which carries contact arms e, e adapted to bear against the contact springs ff. The
lower end of the said spindle is provided with inclined surfaces or cams 9 adapted to
fit into or work upon or against corresponding inclined surfaces or cams / on a fixed
boss which forms a bearing for the spindle.
The inclined surfaces of the spindle are held,against the inclined surfaces of the boss
by means of suitable spring or springs.
The spring shown in the drawing is located within the spindle c which
hollow, one end being secured to the boss i and the other to a pin through the
spindle.
When in the contact position, that is to say, in the position for closing the circuit
the ends of the contact arms press against the contact springs as shown. If the
spindle be now turned by means of its handle one quarter of a revolution the inclined
surfaces 9 sliding against the inclined surfaces h of the boss will cause the spindle to
be raised until the spindle reaches the limit of its upward movement when the
spring will move the spindle down into the next or insulating position as shown in
dotted lines in figure 1, the spring locking the parts in this position until they are
again moved into the contact position by turning the spindle in the opposite direction
to that herein before described.
To prevent the spindle from being moved too far in either direction the lower end
bereof provided with a projection the movement of which is limited by its
impingement against the transverse pin k¹ secured in the boss i.
In the modification of my invention shewn in figures 4, 5 and 6 the contact arms
are not moved directly by the handled but are free to rotate upon the spindle c
Around the said spindle are located two spiral springs 1, one of which is coiled in
a tight hand direction and the other in a left hand direction. The lower end of each

page_text: spring is secured to a collar m on the spindle e as shown in figure 6 and the other
ends of the said springs are connected to a pin n on one of the armis e as shown at o
in figure 4. These springs normally hold the arms e e in one position relatively to
the spindle as they exert forces in opposite directions.
p is a spring catch which is provided at its opposite ends with notches or recesses q, q
which correspond to the two positions of the arms e, e and into which the pin n is
adapted to engage alternately.
r, are two pins or studs which are secured in the collar m and which are adapted
to bear upon the free ends of the catch so as to depress one or other of them as
required to release the pin from its notch, the said spring catch having its two end
portions arranged in an inclined position as shewn in figure 6, whereby the pins 7, 1
are enabled to act thereon.
A recess is cut out of the side of the collar m and a pint is fixed in the base
in such a position relatively to the notch that the spindle c can only be moved the
requisite distance.
""
The operation of this modified form of switch is as follows, that is to say, suppose
the arm e, e to be in the position shown in Figure 4 in contact with the contact
springs. If now the handle d is turned in the direction of the arrow, figure 4, as
far as the pint permits, the spring will be tightened so that the two springs will
exert an unequal action upon the pin; simultaneously with the rotation of the handle d
the pin bears upon the catch p so that the end thereof in which the notch g' is formed
is depressed, whereby the pin n is released. When this takes place the spring
acting upon the pin n causes the arms e to rotate until the tension of the springs 1, 1
is neutral which point corresponds to the position of the arms shown in dotted lines
in Figure 4, in which position the pin n is located in the notch 7. The return of
the arms to their original position is effected by turning the handle d in the reverse
direction to the arrow, when the spring will be tightened and the pin bear upon
that end of the catch in which the notch 9 is formed, to release the pin n therefrom.
The extreme ends of the catch p are inclined so that the pin n can pass freely over
the same to enter the notches q, q¹.
P
With this arrangement the making and breaking of the contact is effected with
great rapidity as no movement of the arms takes place until the pin n is released from
the catch to allow the springs or to re-act.
We wish it understood that we do not limit myself to the constructions herein before
described as it is obvious that we may vary the same without departing from the
nature of our invention.
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. An electric switch so constructed that it will be automatically locked in its
extreme positions and that it cannot remain in any intermediate position, substantially
as described.
2. The improved electric switch consisting of the parts constructed and combined
substantially as hereinbefore described with reference to figures 1, 2 and 3 of the
drawings and operating as, and for the purpose, set forth.
3. The modification of our invention constructed and arranged substantially as
described with reference to figures 4, 5 and 6 of the drawings.
OL 1
1.
1007
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicants.