Improvements in Electric Switches.
Year: 1890

page_text: Date of Application, 27th Feb., 1890
Complete Specification Left, 12th Nov., 1890-Accepted, 20th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in Electric Switches.
1, PHILIP PEMBROKE ALEXANDER of 39 Great Marlborough Street, Regent Street,
in the County of Middlesex, Gentleman, do hereby declare the nature of this invention
to be as follows:-
The switch which forms the object of this invention is especially designed for
putting into circuit a variable number of battery cells, but it may also be used for other,
purposes. It consists of an axis carrying radial contact makers which may conveniently
be brushes. These contact makers are preferably fixed at equal distances apart along
the axis and are also inclined to each other at equal angles. Parallel to the axis is a
straight row of other contact makers consisting of segmental plates each being a
portion of a cylinder whose axis is the axis carrying the radial contact makers. Each
of the segmental contact makers is opposite to one of the radial contact makers and
within its reach and their length is such that the angle they subtend at the axis is
about equal to the angle between the radial contact makers. It results therefore that
the circuit is always completed one or other of the radial contact makers being always
upon one or other of the curved plates; preferably however one pair of contact makers
is omitted to allow of the circuit being broken. By turning the axis the circuit is
completed in succession through the pairs of contact makers, each pair going out of
contact just as the next pair are coming into contact. Resistances may be provided
at the ends of the circular plates so as to prevent the circuit being made and broken
too suddenly.
Dated th: 07th 1
1060
COMPLETE SPECIFICATION.
Improvements in Electric Switches.
I, PHILIP PEMBROKE ALEXANDER, of 39 Great Marlborough Street, Regent Street,
in the County of Middlesex, Gentleman, 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 :-
This invention has for its object a switch for inserting or cutting out of circuit
either battery cells or resistance coils or secondary batteries for regulating purposes.
The improved switch is represented by the drawing annexed which is a side elevation
partly in section. It consists as I prefer to construct it of a base, preferably of wood
such as teak treated with paraffin wax so as to ensure good insulation, which carries
two brackets which may be of cast iron or other suitable material.
These brackets support a rod of circular section of gun metal on which are fixed,
care being taken to ensure good contact, radial gun metal arms, the number of which
depends on the number of coils or batteries to be used in connection with the switch
there being one arm to each coil or battery.
On the base, in the same straight line, between the brackets are fixed contact pieces
corresponding with the above radial arms. These fixed contact pieces are connected,
by means of the bolts which fasten them to the base of the apparatus, to the appro-
priate leads from the batteries or resistance coils. In either case one end of the circuit
is connected to the fixed contact pieces and the other to the bracket of which the
circular brush contact of the main rod forms part, thus giving the necessary
+ and poles.
-
As it is important that only one contact should be made at a time, and also that
there should be as little time as possible between the breaking of one and the making
17

page_text: of the next, the radial arms are so fixed at angles with each other that as one leaves
its fixed contact, on rotation of the handle, the next following makes contact with its
corresponding fixed contact. In the case where this switch is used with secondary
batteries, provision is made for the introduction of suitable resistance between the
making and breaking of any two contacts.
Further a catch is provided which acting by gravity or by a spring, engages with
slots in a ring fixed onto the main rod, in such a way that when any radial arm is
rotated to the central line of its fixed contact, the catch operates and the arm is
retained in that position until released for the next rotation thus preventing any two
arms making contact or partial contact at the same time.
The leads, in the case of secondary batteries are so connected up, there being always
one position where none of the radial arms are in contact, that on rotating the hand
wheel, and No. 1 arm making contact with its fixed contact, one cell is thrown into
the circuit; when No. 2 acts in the same way two cells, No. 3 three cells and so on.
Where resistance coils are being ent in or out, they may obviously be connected in
such a way as to decrease or increase the resistance in circuit as required.
The reference letters on the drawing indicate
A. circular rod of gun metal (or other suitable conducting material) supported by
B B. two brackets of cast iron or other material.
C C. six or other required number of gun metal or other suitable radial arms set
equidistantly and spirally on A each having at its outer extremity a suitable brush
contact, and so arranged that on rotating A by means of
J. a hand wheel each brush in turn comes into contact with its proper contact piece.
The hand wheel J may be insulated from the rod A.
F F. gun metal contact pieces to which resistance coils or battery leads are attached
in the last case proper provision being made for insertion of resistances. The drawing
indicates the connection with a series of resistance coils R R.
D is a circular flanged gun metal dise suitably fixed at one end of and concentric
with A, the flange projecting outward from the apparatus and making contact with
E a fixed brush with its supporting bracket, the whole forming an attachment to
the bracket B.
on.
GG are bolts attaching B to the base; the current passes through E to A and so
The main lead is attached here.
H is a gun metal collar having slots or holes cut in its periphery which receive a
moveable stop, the slots being six in number to correspond with the radial arms so
that the stop engages in a slot only when the corresponding arm is perpendicular to
the base of the apparatus.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. An electric switch consisting of an axis capable of rotating and having radial
arms carrying brushes or contact parts and another corresponding set of contact parts
upon a stationary base or foundation; the whole so arranged that the rotation of the
axis brings the contact parts carried by the radial arms successively to rub or bear
against the corresponding stationary contact parts so completing in succession a series
of electric circuits as herein set forth.
2. An electric switch substantially as described and represented by the annexed
drawing.
Dated this 5th day of November 1890