Improvements in Electrical Switches for Telephonic Systems and other purposes.
Year: 1899

page_text: Date of Application, 3rd Nov., 1899- Accepted, 27th Jan., 1500
COMPLETE SPECIFICATION,
Improvements in Electrical Switches for Telephonic Systems
and other purposes.
We, MAX BYNG, Electrical Engineer, and FRANCIS GEORGE BELL, Electrician,
both of Nos. 69-71-88-92, Queen Victoria Street, in the City and County of
London, 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 certain improvements in switches applicable to tele-
phonic systems and other purposes, in which several contact points are controlled
by one switch arm, lever, or like contact, and the object thereof is to provide a
distinct check, audible and distinctly sensible to the touch of the operator, thus
indicating each movement and further, affording a mechanical check at each
point.
In order that our invention may be clearly understood, we have appended the
accompanying sheets of drawings in which Figure 1 Sheet 1 is a front elevation
of the switch and Figure 2 a side elevation thereof, Figure 3 showing the under
side of the switch contact bar, and the checking device, and Figure 4 a part
sectional view drawn to an enlarged scale showing the actual check upon the
switch or contact arm. Upon Sheet 2, Figure 5 is a front elevation of a sliding
switch constructed according to our invention, and Figure 6 a plan view thereof,
and Figure is a cross section of the same. Like reference letters refer to
corresponding parts throughout the several views where applicable.
In carrying our invention into effect we use a switch arm A Figures 1, 2, 3, 4
Sheet 1, which is pivotted at a, and makes contact respectively with the contact
studs b, as it is turned to right or left upon its axis a. The switch arm A,
instead of being pivotted directly to the switchboard D is rotated upon a set
screw a passing through, and held by a plate E which is supported away from
the board D by screws and distance pieces or collars e and upon the under
side of which are formed countersunk hemispherical recesses f. A ball g passes
freely through the switch lever or arm A and engages with either of the recesses f
which may be contiguous to its desired position, it being understood that a
radial line drawn through any of the contact studs 6 passes through the centre
of the corresponding recess or countersink on the underside of the plate E. The
diameter of the ball being greater than the thickness of the switch arm A.
projects beyond it and is kept in position by means of a flat spring suitably
shaped, and rigidly attached to the arm A.
Said spring his continued beyond the holding screws ii connecting it to the
arm A thus adding to the pressure imparted by the contact springs kand
balancing the arm A during its movement. Therefore when a radial movement
of A is made in either direction to make contact with any of the contact studs b
the act of so moving it displaces the ball from one of the recesses f against
the tension of the spring h (this arrangement being shown more particularly by
the enlarged view Figure 4 Sheet 1) and causes an audible "click" and also a
mechanical check as it engages with the next recess f. This prevents a false

page_text: contact which would occur if the switch arm A was placed between two contact
studs b.
A modification of this device is shown by Figures 5; 6 & 7 Sheet 2 in which
the switch arm is shown sliding upon a bar F.making contact with studs b'suitably
insulated. The arm A is freely suspended upon the bar F by means of a
carrier M which also serves as a holder or handle for moving A from contact to
contact. A spring h, attached to A. by a screw i also connecting A to the
carrier M, is pressed against the lower end of the arm A and forces it upon the
contact studs and also upon the bar G which is perforated or countersunk in
spaces corresponding to the contacts b, these being shown by f, the lower end
of the arm A carrying a ball g, which affords an audible signal and a mechanical
check in a linear direction instead of a radial direction as described in the first
instance. The motion of the arm A upon the bar F carried by the carrier M
may be horizontal angular or vertical.
We do not confine ourselves to any particular kind of switch to which the
ball check according to our invention may be applied, but may adapt it to any
form in which one contact arm or lever has to complete an electrical circuit in
several branches by its contact with any one of several studs or contact pins.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
First. In electrical switches the combination of a switch arm with a ball
pressed by a spring into spaced recesses, substantially as herein described and
shown by the drawings.
Second. In electrical switches the combination of a radial switch arm with
two or more contact studs, pressed, thereon by a spring, and carrying a ball
engaging with spaced countersunk recesses in a plate to act as an audible and
mechanical check, substantially as herein described and shown by the appended
drawings.
Third. In electrical switches the combination of a sliding switch arm with
two or more contact studs, the contact being preserved by the pressure of a
spring upon the lower part of the switch arm which carries a ball, engaging
with spaced recesses formed in a bar parallel with the guide bar forming an
audible and mechanical check substantially as herein described and shown by
the appended drawings.
Fourth. In electrical switches the employment and use of a ball in combination
with a spring attached to the arm, the said ball engaging with recesses in a
fixed plate or bar, the position of each corresponding to the contact studs, sub-
stantially as and for the purposes herein described, and shown by the appended
drawings.
Dated this 28th day of October 1899.
FREDK. WALKER,
.73, St. Stephen's Road, Upton Park, London, E.C.