An Improvement in Switches for Electric Circuits.
Year: 1894

page_text: Date of Application, 2nd Oct., 1894
Complete Specification Left, 2nd July, 1895-Accepted, 3rd Aug., 1895
PROVISIONAL SPECIFICATION.
An Improvement in Switches for Electric Circuits.
We, THE ACME & 1MMISOH ELECTRIC WORKS, LIMITED, and ERNEST
FRANCIS MOY, Electrical Engineer, both of Ferdinand Street, Chalk Farm, N.W.,
in the County of London, do hereby declare the nature of this invention to be as
follows:-
:-
This improvement relates to switches used for making and breaking electric
circuit councctions, and it refers to improvements upon a special class of cylindrical
contact switches in which an arm or bridge piece is adapted to move on a centre
or axis and make an interior circumferential contact against fixed contact pieces' or
terminals arranged upon one or more arcs of a circle or circles. Examples of
the said class of cylindrical contact switches are described and illustrated in
Iliffe & Barton's Specification to Letters Patent dated 1st November 1890,
No. 17560.
In the aforesaid Specification, each cylindrical contact consists of two plates, one
mounted upon the other, each forming an arc of a circle. The upper plate is inade
with a bottom flange or base on which it is seated on the lower plate, while its
inward portion stands well up in the form of a segment of a cylinder to provide an
interior or cylindrical contact surface for the brush or brushes carried by the bridge
piece. By means of slotted holes in the bottom flange of the upper plate, and set
screws passing through the same and engaging with the lower plate, provision is
made by adjusting inwardly to compensate for wear of the contact surfaces. The
arm or bridge piece is not made adjustable in itself, but the brush at its end or ends,
being made of a number of thin plates and bent to present an inclined surface to the
contact surface, gives a spring action, and therefore also tends to compeusate for
wear and to make good contact with the terminals.
By this present invention the arm or bridge piece is in itself made adjustable by
This is in addition
outward radial extension, in order to compensate for wear.
to any elasticity or spring given to the brush or brushes carried by the arm.
Consequently, each cylindrical contact is not required to be made adjustable, as
hitherto, but is more cheaply and conveniently constructed solid. By making the
arm or bridge piece adjustable in a radial direction, and avoiding the necessity of
adjusting each terminal separately, the improvement is applicable to either single
pole or multiple contact switches; and is therefore suitable for ordinary circuits,
resistances, battery charge and discharge regulators, reversing switches, and the
like. The arm or bridge piece is made adjustable by adapting one or more parts
to slide upon, or within or without, the central or pivoted portion moved by the
handle, with set screws or other suitable means to secure the said parts in any
required relative position. More than one arm or bridge piece may be carried
upon or by the said central part, with a corresponding number of contact making
brushes.
Dread thin and day of Ontober 1894

page_text: We, THE ACUE & IMMISCH ELECTRIC WORKS, LIMITED, and ERNEST
FRANCIS MOY, Electrical Engineer, both of Ferdinand Street, Chalk Farm, N.W.,
in the 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 :-
This improvement relates to switches used for making and breaking electric circuit
connections; and it especially refers to improvements upon a special class of
cylindrical contact switches in which an arm or bridge piece is adapted to move on
a centre or axis and make interior circumferential contact against fixed contact
pieces or terminals, arranged upon one or more arcs of a circle or circles. Examples
of the said class of cylindrical contact switches are described and illustrated in
Iliffe & Barton's Specification to Letters Patent, dated 1st November 1890,
No. 17560.
In the aforesaid Specification, each cylindrical contact consists of two plates,
one mounted upon the other, each forming an arc of a circle. The upper plate is
made with a bottom flange or base on which it is seated on the lower plate, while
its inward portion stands well up in the form of a segment of a cylinder to provide
an interior or cylindrical contact surface for the brush or brushes carried' by the
bridge picee. By means of slotted holes in the bottom flange of the upper plate,
and set screws passing, through the same and engaging with the lower plate,
provision is made by adjusting inwardly to compensate for wear of the contact
surfaces. The arm or bridge piece is not inde adjustable in itself, but the brush
at its end or ends, being made of a number of thin plates and bent to present an
inclined surface to the contact surface, gives a spring action, and therefore also
tends to compensate for wear and to make a good contact with the terminals.
By this present invention the arm or bridge piece is in itself made adjustable by
outward radial extension, in, order to compensate for wear. This is in addition
to any elasticity or spring given to the brush or brushes carried by the arm.
Consequently, each cylindrical contact is not required to be made adjustable, as
hitherto, but is more cheaply and conveniently constructed solid. By making the
arm or bridge piece adjustable. in a radial direction, and avoiding the necessity of
adjusting, each terminal separately, the improvement is applicable to either single
pole or inultiple contact switches; and is therefore suitable for ordinary circuits,
resistances, battery, charge and discharge regulators, reversing switches, and the
like. The arm or bridge piece is made adjustable by adapting one or more parts
to slide upon, or, within, or without, the central or pivoted portion moved by the
handle, with set screws or other suitable means to secure the said parts in any
required, relative position. More than que arm, or bridge picce inay be carried
upon or by the said central part, with, a corresponding number of contact making
brushes.
1.
In the further description of this invention reference is made to the accompanying
drawings, in which, Fig. is a plan and Fig. 2 a-sectional elevation of a resistance
switch, showing one form of adjustment; and Fig. 3 is a plan and Fig. 4 a sectional'
elevation of a battery regulating switch, showing a modified mode of adjustment.
In these drawings, a is the arm or bridge piece; b, b, are the contact making brushes,
made of thin sheets of copper, or in some other equivalent manner, c, c, are the
several cylindrical contact pieces or terminals, which are fed (for example) from a
general or supply terminal d, or it,may be the opposite direction.
In Figs. 1 and 2, the arm or bridge piece a is shown as mounted to turn upon a
central stud in a convenient manner, and it carries an extension piece a loosely
fitting upon a, substantially forming a part thereof. An adjusting screw a³ passes

page_text: through a flange of the extension piece and bears upon a, so that when screwed up
against the latter an outward radial extension takes place, and the set screws a³ are
screwed down to hold the extension piece in the required position. By this means
a sufficient amount of pressure can always be maintained upon the bent elastic
brushes 6 to ensure good electrical contact; and a similar arrangement is provided
at the opposite end (not shown) to ensure the like contact against the general
terminal d. A handle e is used to turn the arm a, and the whole is mounted upon
a suitable base.
C
The same general arrangement is followed in the case of the battery regulatiog
switch, shown in Figs. 3 and 4. In this example the bridge piece or arm a, with
its two extension pieces a', are radially adjusted by the two adjusting screws a²,
which are adapted to adjust either of the extension pieces as required. When, for
example, the brush contact against the battery terminals is insufficicnt owing to
wear, the two set screws a³ shown on the left are loosened, while the set screw a³
on the right hand side of the figures is kept tight. The two adjusting screws a² are
then turned in a direction to force the extension piece al with its flexiblo or elastic
brush in a radial direction to the left, thus making closer contact with the
terminals c. When the required adjustment has been made, the two set screws a³
on the left are tightened. Likewise, compensation for wear is made against the
general terminal d by slacking out the set screw a³ on the right hand side and
turning the adjusting screws a³, as before. It will thus be seen that the set screw
or screws a³ which is or are tightened serves as an abutment for the screws a² in the
radial adjustment of the opposite extension piece a'. A double handle e is shown in
this switch.
Having now particularly described and ascertained the nature of our said inven-
tiou, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The herein described improvement in switches for electrical circuits consisting
of a radially extensible and adjustable bridge piece or arm combined with cylindrically
formed contact terminals, substantially as and for the purpose specified and shown
in the drawings.
2. In an electric switch, the combination of a movable bridge piece or arm a
combined with an extension piece a', an adjusting screw or screws a², set screws a³,
a flexible or elastic contact making brush b and terminals c and d having interio
cylindrical contact surfaces, substantially as and for the purpose herein described
and shown by the drawings.
Dated this 2nd day of July 1895