Improvements in or relating to Starting Switches for Electro-motors or the like.
Year: 1898

page_text: Date of Application, 12th Dec., 1898
Complete Specification Left, 9th Sept., 1899-Accepted, 21st Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in or relating to Starting Switches for Electro-motors
or the like.
I, JOHN WALTER GIBBS, of 72, 74, and 76, Duke Street, Liverpool, in the
County of Lancaster, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to that type of starting switch for electro motors in
which the motor is set into motion before the full electric potential is supplied
to it, thus avoiding injury to the apparatus which would be liable to occur if
a high electric potential were supplied at the outlet.
In one apparatus, namely that set forth in my Patent No. 13717, of 1897, a
series of contact studs are arranged in the segment of a circle, the highest
resistance contact being at one end and the others gradually reduced down to
the lowest resistance. The switch arm travels over these contact studs and as
it does so, the resistances, are cut out one after the other, and the potential of
the current gradually increased until the arm reaches the final point at which
the potential is at its maximum. In order to cause the switch arm to automa-
tically fly back upon the failure of the supply of current, an arrangement has
been provided consisting of a spring which is wound up when the switch arm is
moved over the contact studs from the highest to the lowest resistance contact,
but which is instantly returned by the spring when released. The arm how-
ever is prevented from returning by a pawl, engaging with a ratchet wheel
upon the spindle of the switch arm (or on another spindle geared thereto) so
long as the armature forming part of the pawl is attracted by an electro magnet,
and the arm therefore cannot be returned until it is returned automatically by
a failure of the supply of current.
The object of my present invention is to enable the switch arm to be returned
by hand to the point of highest resistance (or to be varied by hand from full to
zero), even when the ratchet wheel is locked by the pawl, and I am thus able to
vary the electric potential by hand as required by circumstances. This I effect
by mounting the switch arm loosely on its spindle or axis, and in providing an
auxiliary arm or follower mounted and fixed to the said spindle, on which the
ratchet wheel that is acted on by the armature pawl is fixed. This auxiliary
arm or follower is located in the same plane as the switch arm, and slightly in
advance of the latter, so that in moving the, switch arm over the contact studs
to cut out the resistances one by one, it will push the follower before it, and so
rotate the spindle and its ratchet wheel, which latter engaging with the arma-
ture pawl prevents the follower returning so long as there is no failure in the
supply of current sufficient to cause the electro-magnet to cease to attract its
armature. The switch arm however being separate from the follower it can
be turned back by hand over the contacts so as to vary the resistance as required.
This is a very important point as I am thus able to increase or decrease the
potential of the current at pleasure. At the same time this arrangement does

page_text: not prevent the automatic release of the ratchet wheel, as should there be a
failure in the supply of current, and the electro-magnet be no longer energised,
the pawl will at once automatically release the ratchet wheel, and the follower
instantly flies back by the agency of the spring, said follower automatically
pushing back the switch arm to the zero position. I may also provide if desired
another electro-magnet on the other side of the armature, so arranged as to be
energised only in case of an abnormally high electric potential, which will attract
the armature away from the other electro magnet and thus draw the pawl out
of its engagement with the ratchet wheel, causing the switch arm to fly back
to its point of highest resistance.
T
Improvements in or relating to Starting Switches for Electro-motors
or the like.
I, JOHN WALTER GIBBS, of 72, 74, and 76, Duke Street, Liverpool, in the
County of Lancaster, Engineer, 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:-
1
1.11
This invention. relates to, that type of starting switch for electro motors.in
which the motor is set into motion before the full electric potential is supplied
to it, thus avoiding injury to the apparatus which would be liable to occur if
a high electric potential were supplied at the outset.
In one apparatus, namely that set forth in my Patent No. 13717, of 1897, a
series of contact studs are arranged in the segment of a circle, the highest
resistance contact being at one end and the others gradually reduced down to
the lowest resistance. The switch arm travels over these contact studs and as
it does so, the resistances are cut out one after the other, and the potential of
the current gradually increased until the arm reaches the final point at which
the potential is at its maximum. In order to cause the switch arm to automa-
tically fly back upon the failure of the supply of current, an arrangement has
been provided consisting of a spring which is wound up when the switch arm is
moved over the contact studs from the highest to the lowest resistance contact,
but which is instantly returned by the spring when released. The arm how-
ever is prevented from returning by a pawl, engaging with a ratchet wheel
upon the spindle of the switch arm (or on another spindle geared thereto) so
long as the armature forming part of the pawl is attracted by an electro magnet,
and the arm therefore cannot be returned until it is returned automatically by
a failure of the supply of current.
The object of my present invention is to enable the switch arm to be returned
by hand to the point of highest resistance (or to be varied by hand from full to
zero), even when the ratchet wheel is locked by the pawl, and I am thus able to
vary the electric potential by hand as required by circumstances. This I effect
by mounting the switch arm loosely on its spindle or axis, and in providing an
auxiliary arm or follower mounted and fixed to the said spindle, on which the
ratchet wheel that is acted on by the armature pawl is fixed.
In the accompanying drawings:.
i

page_text: Figur 1 is a front view of the starting switch with my present invention
applied thereto;
Figure 2 a back view;
Figure 3 a cross section.
Referring to these figures, the reference letters indicated thereon will be
understood by referring to the specification of my prior patent aforesaid. The
other parts not referred to in said patent will be understood from the following
description, reference being had to the accompanying drawings.
The switch arm J is loosely mounted on the spindle or axis T and an auxili-
ary arm or follower U is mounted and fixed to the said spindle on which a
ratchet wheel V, which is acted upon by the armature pawl Y is fixed. This
auxiliary arm or follower U is located in the same plane as the switch arm J
and slightly in advance of the latter. ✗ is an electro-magnet and Y a pawl
adapted to engage in the ratchet wheel V. So long therefore as the magnet
is supplied with current, the pawl by means of its armature Y¹ being attracted
by the magnet, is kept in engagement with the ratchet wheel. Z is a spring
which is wound up on moving the follower U forward, but which forces the
follower back to the zero position immediately the pawl releases the ratchet
wheel on the failure of the supply of current.
The mode of operation is as follows:-
To switch on the current, the handle H is moved into the position shewn in
Figure 3, but this is only possible when the recess or slot G of the interlocking
shield E is opposite the tongue D of the double pole switch C, and the resist-
ance arm J is in the position shewn in Figure 1 that is in contact with the
highest resistance contact stud K¹.
The current being on, the switch arm J can be turned by means of handle J'
so as to switch out one contact after the other until it reaches the lowest resist-
ance K². In thus moving the switch arm over the contact studs to cut out
the resistances one by one it will at the same time push the follower U before it
and so rotate the spindle T and its ratchet wheel V, which latter engaging with
the armature pawl Y prevents the follower returning so long as there is no
failure in the supply of current sufficient to cause the electro-magnet X to cease
to attract its armature Y. The switch. arm however being separate from the
follower U can be turned back by hand over the contacts K so as to vary the
resistance as required. This is a very important point as I am thus able to
increase or decrease the potential of the current and consequently the speed of
the motor at pleasure. Should however there be a failure in the supply of cur-
rent and the electro-magnet X be no longer energized, the ratchet wheel V will
be at once released from the pawl. In such case the pawl will no longer be
kept in gear with the ratchet wheel, which latter will thus be instantly released
automatically, and the follower at once flies back by the agency of the springs Z,
said follower automatically pushing back the switch arm to the zero position.
I may also provide if desired another electro-magnet on the other side of the
armature, so arranged as to be energised only in case of an abnormally high
electric potential, which will attract the armature away from the other electro
magnet and thus draw the pawl out of its engagement with the ratchet wheel,
causing the switch arm to fly back to its point of highest resistance.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim is: :-
1. In starting switches of the kind in which the potential of the current is
gradually increased by moving a switch arm over resistance contacts varying
from the highest to the lowest resistance; the arrangement for enabling the
electric potential to be varied by hand, or in the event of failure of the supply
of current, to enable the switch to return automatically to its point of highest
resistance, which consists in mounting the switch arm loosely on its spindle or

page_text: axis and in providing a separate arm or follower mounted and fixed to the said
spindle or axis immediately in advance of, but separate from, the switch arm,
so that it will be pushed forward by the latter, and means for locking the said
follower when pushed forward so that it cannot be returned, until automatically
returned by a failure in supply of current, whereby the switch arm being sepa-
rate from the follower, can be turned back by hand over the contacts to vary
the resistance as required, or will be automatically forced back by the follower
to the point of highest resistance immediately the locking mechanism is released
by a failure in the current supply, substantially as described.
2. In starting switches of the kind described, the combination with the switch
arm mounted loosely on its spindle or axis and capable of being travelled over
a series of resistance contacts varying from the highest to the lowest resistance,
a separate arm or follower mounted and fixed to said spindle or axis immediately
in advance of but separate from the switch arm, so that it will be pushed for-
ward by the latter, a ratchet wheel V secured to the end of said spindle, an
electro-magnet X, and a pawl Y (with armature Y¹) capable of engaging the
ratchet wheel, whereby so long as the magnet is supplied with current, the pawl
by means of its armature being attracted by the magnet is kept in engagement
with the ratchet wheel, thus locking the follower, but immediately a failure in
the supply of current takes place, the follower will force back the switch arm
to the point of highest resistance, substantially as set forth.
Dated this 8th day of September 1899
WM. P. THOMPSON & Co.,
Patent Agents, of Liverpool, Manchester, Birmingham, and London.