Improvements in Electrical Switches.
Year: 1890

page_text: Date of Application, 12th Sept., 1890
Complete Specification Left, 12th June, 1891-Accepted, 18th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in Electrical Switches.
I, CHARLES SCOTT SNELL of Culver Park Saltash in the County of Cornwall
Engineer and Designer do hereby declare the nature of this invention to be as
follows
-
The object of this invention is to produce a switch for electrical purposes which
shall in both making & breaking the circuit act under the influence of a spring or
springs, independently of the handle which may indeed have no direct influence
upon or in connection with the switch.
Now I am aware of various arrangements by which this effect in whole or in part
has been attempted, that one Specification notably Holmes' No. 3256-84 describes
the simple expedient of allowing the handle to have a certain amount of free
rotation relatively to the switch arm, and a spring tending to pull "off" all the time:
the contacts gripping the arm when "on
"and wards in connection with the handle
or key to force the arm off or to force it on as may be required, the only function
of the spring being to accelerate the rate of breaking of the contact and therefore
to lessen the danger of sparking at this time.
Now 1 propose to make use of a diamond or lozenge shaped cam or equivalent
appliance gripped between one or more powerful springs (practically as in use a
considerable time ago) but instead of allowing the lozenge to be to all intents and
purposes a rigid attachment to, or part of the switch arm, I allow it to freely and
independently move through a considerable number of degrees, before it affects the
movements of the said arm and by controlling its action to thereby indirectly control
the movement of the switch arm. The aforesaid springs for instance may be fitted
to press from diametrically opposite points towards the centre spindle upon which
the lozenge rotates and which indeed is common also to the switch arm; now it is
plain the lozenge can be so turned as to keep the springs apart and there remain
on the dead centre, if however in moving a few degrees to either side of this it
begins to engage with the switch arm (either through pins working in elongated
holes or in any other convenient manner) it is evident that in whatever direction
the lozenge or its equivalent may be started such will be the ultimate direction of
rotation of the switch arm, it will then be readily seen that motion in reverse
directions is possible from this action and that by controlling this movement of the
lozenge one can control (with all the advantages of quick spring action) the " on
or "off" movement of the switch arm.
The handle proper may be mounted in any convenient position relatively to the
lozenge but it is immaterial as regards the switch arm for instance it may be
mounted alongside the lozenge and control it by a gear wheel with slots therein to
allow of rotation for a certain number of degrees, so that if the hand be held still
after starting the direction of rotation, the switching movement may still be com-
pleted; for convenience although not acting or in any way affecting it the handle
may still rotate upon the main spindle.
This switch handle therefore does not directly move the switch arm & requires
no direct connection therewith neither need any impulse therefrom be directly
transmitted to the switch arm the movement is simply a reaction combined with
absolute control of direction of rotation. The springs work the switch, the handle
directs the turning effort of the spring or springs.
This switch it will be seen is retained by (not against the force of the spring or
springs in the "on" as well as the "off" positions thus adding to its security, it
therefore does not require to be gripped by the contact pieces and the actuating
mechanism as represented by the handle or key does not push the contact bar or

page_text: arm before it either when bringing it into contact or out nor indeed has any direct
connection therewith; and the spring or springs are always at rest when the switch
is either on or off. The function then of the handle is to form a medium for
acting upon or giving motion to a spring or springs in a position of rest and
controlling the direction in which the reaction shall take effect (in contradistinction
to the usual slow moving rigidly attached handle and the direct acting contact
making and releasing handle which in switching "off" is used to relieve an already
strained spring) and this principle whilst not patentable in the abstract is neatly &
simply embodied in the above described construction.
Dated this 10th dor of Canto
C. SCOTT SNELL.
COMPLETE SPECIFICATION.
Improvements in Electrical Switches.
CHARLES SCOTT SNELL, of Culver Park Saltash Cornwall Engineer and
Designer, 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 object of this invention is to produce a switch for electrical purposes which
shall in both making and breaking the circuit act under the influence of a spring
or springs independently of the handle which may indeed have no direct influence
upon or connection with the switch.
Now I am aware of various arrangements by which this effect in whole or in part
has been attempted, that one Specification notably Holmes No. 3256, of 1884 describes
the simple expedient of allowing the handle to have a certain amount of free rotation
relatively to the switch arm and a spring tending to pull "off" all the time, the
contacts gripping the arm when " on and wards in connection with the handle or
key to force the arm off or to force it on as may be required the only function of
the spring being to accelerate the rate of breaking of the contact and therefore to
lessen the danger of sparking at this time.
"
Now I propose to make use of a diamond or lozenge shaped cam or equivalent
appliance gripped between one or more powerful springs (practically as in use a
considerable time ago) but instead of allowing the lozenge or its equivalent
marked A in the drawings and hereafter referred to as the lozenge, to be to all
intents and purposes a rigid attachment to, or part of the switch arm, I allow it
to freely and independently move through a considerable number of degrees before
it affects the movement of the said arm marked B, and by controlling its action to
thereby indirectly control the movement of the switch arm. The aforesaid springs
for instance may be fitted to press from diametrically opposite points towards the
centre spindle upon which the lozenge rotates and which indeed is common to the
switch arm, now it is plain the lozenge can be so turned as to keep the springs
apart and there remain on the dead centre (it being obvious that the handle or key
having recesses as shown in Fig. 6 inverted plan to engage with the lugs on the
lozenge this is readily effected if however in moving a few degrees to either side of
this it, the lozenge, begins to engage with the switch arm (either through pins
working in elongated holes or in any other convenient manner) it is evident that in
whatever direction the lozenge or its equivalent may be started such will be the
ultimate direction of rotation of the switch arm it will then be readily seen that
motion in reverse directions is possible from this action and that by controlling the
movement of the lozenge one can control (with all the advantages of quick spring
action) the " on or "off" movement of the switch arm.
"
This action may be clearly followed from diagrams Figs. 3, 4, 5. In Fig. 3 the
lugs D are turned from right to left by the handle until the position shown in Fig. 4
is taken up when the handle may be held still and the springs, (acting upon the pins
on the lozenge beyond the dead centre point) will carry the switch arm round the

page_text: position shown in Fig. 5, on turning the key back again the quick spring motion is
again obtained but in the reverse direction. The handle proper may be mounted
in any convenient position relatively to the lozenge but it is immaterial as regards
the switch arm, for instance it may be mounted alongside the lozenge and control
it by a gear wheel with slots therein to allow of rotation for a certain number of
degrees so that if the hand be held still, after starting the direction of rotation the
switching movement may still be completed for convenience however although
not acting or in any way affecting it the handle may still rotate upon the main
spindle.
This switch handle therefore does not directly move the switch arm and requires
no direct connection therewith, neither need any impulse therefrom be directly
transmitted to the switch arm, the movement is simply a reaction combined with
absolute control of direction of rotation. The springs work the switch the handle
directs the turning effort of the springs. This switch it will be seen is retained by
(not against the force of) the spring or springs in the "on" as well as "off" position
thus adding to its security it therefore does not require to be gripped by the contact
pieces and the actuating mechanism as represented by the handle or key does not
push the contact bar or arm before it either when bringing it into contact nor
out of contact nor indeed has any direct connection therewith, and the spring or
springs are always at rest when the switch is left either "on
"
<6
or off."
The function then of the handle is to form a medium for acting upon or giving
motion to a spring or springs in a position of rest and controlling the direction in
which the reaction shall take effect in contradistinction to the usual slow moving
rigidly attached handle and the direct acting contact making and releasing handle
which in switching off is used to relieve an already strained spring and this
principle is neatly, simply, economically, and symmetrically embodied in the above
described construction.
Having now particularly described and ascertained the nature of my inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is-
1st. The construction or combination of the parts of a switch whereby an inter-
mediate lozenge or its equivalent is used to receive the impulse from the handle
against the force of suitable springs, in such a manner that after a certain degree
of rotation the said lozenge being turned beyond the "dead centre" position these
springs in returning towards their normal position cause the lozenge to continue its
motion and, although the handle be held rigid, to carry the switch arm
"off" contact as may be desired, substantially as and for purposes herein described
and illustrated in the accompanying drawings.
66
"
on or
2nd. The construction of a switch in which a plate with lugs and pins forming
a lozenge or its equivalent placed under the switch arm or brush substantially
as and for the purposes herein described and illustrated in the accompanying
drawings.
Dated this 12th day of June 1891
C. SCOTT SNELL.