Improvements in Switches for Electromotors and the like.
Year: 1899

page_text: Date of Application, 16th Jan., 1899
Complete Specification Left, 16th Oct., 1899-Accepted, 18th Nov.,
1899
PROVISIONAL SPECIFICATION.
Improvements in Switches for Electromotors and the like.
We, ROBERT ALEXANDER SLOAN and JOHN EDWARD LLOYD BARNES, both of
34, Castle Street, Liverpool, in the County of Lancaster, Consulting Engineers,
do hereby declare the nature of this invention to be as follows:-
This invention relates to switches for electro-motors and the like, and has
for its object the provision of combined controlling and main switches so
arranged that whilst the latter can be opened independently of the former, it
can only be closed when the controlling switch is in the proper position for
starting a further object is to combine with the main switch an automatic
device by means of which the main switch is opened, preferably by a hammer-like
action, when the current falls below or rises above certain predetermined limits,
but which device is rendered inoperative when the main switch is opened by hand.
We will describe our invention with reference to an arrangement comprising
a controlling switch having, say, six points connected to suitable resistances
adapted to vary the strength of the main and field circuits of the motor, and
a main switch, preferably of the double-pole quick-break type.
We provide a locking piece attached to the handle of the controlling switch
which will be referred to as the locking piece C, and a locking piece, which will
be referred to as the locking piece M, attached to the handle of the main switch,
which handle, as the latter is of the quick-break type, is capable of a limited
movement relatively to the switch; the locking pieces are so arranged that the
locking piece C limits the movement of the locking piece M so as to effectually
prevent the closing of the main switch except when the controlling switch is
in the starting position; when the main switch is closed the locking piece M
limits the movement of the locking piece C so as to prevent the movement of
the controlling switch until the handle of the main switch is moved, without
of course opening the main switch, so as to be again locked by the movement
of the controlling handle from the starting position; the main switch is thus
prevented, should it be opened in the meantime, from being closed again till
the controlling switch is moved back to the proper position for starting. It will
be seen that the main switch is not locked against opening in any position of
the controlling switch.
We also provide in combination with the main switch a weighted lever which
is moved by the handle of the main switch, as the latter is closed, to its top
position, and which is held in this position against the force of gravity by an
electro-magnet energised by the main current or a shunted portion thereof;
should the main current be broken, say from a failure of the supply, or fall in
strength below a predetermined limit in consequence, say, of the motor being
underloaded, the magnet releases the lever and the latter in falling opens the
main switch, which, as described, cannot be closed again till the controlling
switch is moved to the starting position. When the main switch is opened by
hand the downward movement of the lever, which is then of course released by

page_text: the holding electro-magnet, is limited so that its hammer-like action is pre-
The action of gravity may be assisted or replaced by the action of a
vented.
spiral spring.
The main switch is fitted with double-pole fuses, but where the latter are
not relied upon to guard against excess of current a second electro-magnet is
fitted whose armature, when the maximum prescribed limit is reached, either
breaks the circuit of the holding electro-magnet, or short-circuits it, whereupon
the main switch, as before, is opened.
Dated this 14th day of January 1899.
Improvements in Switches for Electromotors and the like.
We, ROBERT ALEXANDER SLOAN and JOHN EDWARD LLOYD BARNES, both of
34, Castle Street, Liverpool, in the County of Lancaster, Consulting Engineers,
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 relates to switches for electro-motors and the like, and has
for its object the provision of a combined regulating and main switch so arranged
that whilst the latter can be opened independently of the former, it can only
be closed when the regulating switch is in the proper position for starting.
We have illustrated our invention in the accompanying drawings in which
Fig. I is an elevation of a combined regulating and main switch, Fig. II is a
plan view in section on the line A, A, of Fig. I; and Figs. III and IV are
side elevations in section on the line B, B, of Fig. I, showing the operative parts
in different positions.
Throughout the drawings similar parts are indicated by the same reference
figures, and in the case of sections, the direction in which they are viewed is
indicated by the small arrows placed adjacent to the letters denoting the plane
of section.
The arrangement shown comprises a regulating switch 1 having nine points
connected to suitable resistances adapted to vary the strengths of the main and
field circuits of the motor, and a main switch 2 of the double-pole, quick-break
type. The latter being in its main features of a well known pattern, details
not relevant to our invention are omitted or shown conventionally, and there
being no special features in the electrical connections, these latter are not shown.
C is a locking piece attached to the handle 3 of the regulating switch, and M
is a locking piece attached to the handle 2 of the main switch; the latter being
of the quick-break type, the handle is capable of a limited movement relative
to the switch bars 2b without operating the latter.
The locking pieces are so arranged that the piece C limits the movement of the
piece M so as to effectually prevent the closing of the main switch except when
the regulating switch is in the starting position, as shown in full lines in Fig. I
and in Fig. III; in every other position of the regulating switch, the piece C,
(which is supported by the abutment 4 over which it slides), lies under the
point of the piece M and prevents the handle 2 from being thrown over far
nough to close the main switch: this is shown in Fig. IV, where the regulating
switch has been moved into the position shown in dotted lines in Fig. I, and
the switch bars can consequently only be moved over as far as the position shown
in dotted lines.

page_text: When the main switch has been closed, the curved edge of the piece M limits
the movement of the piece C, so as to prevent the movement of the regulating
switch from its starting position until the main handle 2 has been moved back,
without of course opening the main switch, into the position shown in Fig. IV,
so that it will be again locked as soon as the regulating switch is moved on
from the starting position, and if the main switch be opened in the meantime,
it cannot be again closed until the regulating switch is again replaced in the
starting position.
It will be seen that the main switch is not locked against opening in any
position of the regulating switch; also that it is impossible for the attendant
to hold the main switch bars in the closed position after moving the regulating
switch from its starting position. This latter feature is of great importance
if automatic under-load or over-load circuit breaking devices be arranged to act
directly on the main switch-bars 2b, as otherwise these devices might be inadver-
tently prevented from operating by the attendant whilst starting the motor.
No claim is made herein broadly to the mere locking of the main switch by
the regulating switch, as devices of this class wherein one switch must be
operated before another can be operated are well known. Broadly, the main
feature of our invention is not the mere locking of the main switch by the
regulating switch but the peculiar mutual interlocking action described.
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:-
1. A motor starting switch comprising a main switch and a regulating switch,
the latter and the loose handle of the former being so mutually interlocked that
the main switch cannot be closed except when the regulating switch is in the
starting position, and that the regulating switch cannot be moved from the
starting position until the main switch handle has been drawn back sufficiently
to allow the main switch bars to open; substantially as described and illustrated.
2. In a motor starting switch in combination; a main switch, a regulating
switch, a locking piece such as C attached to the latter and a locking piece such
as M attached to the loose handle of the former, of such form that it locks the
piece C until the handle has been withdrawn so as to leave the main switch
bars 2 free to open; substantially as described and illustrated.
3. The combination and arrangement of parts forming the improved motor
starting switch; substantially as described and illustrated.
Dated this 14th day of October 1899.
SLOAN & LLOYD BARNES,
Chartered Patent Agents, 34, Castle Street, Liverpool..