Improvements in Switches for Starting and Controlling Electric Motors.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Switches for Starting and Controlling Electric
Motors.
We, HUGO HIRST, of 69-71-88-92, Queen Victoria Street, in the City and County of
London, Electrical Engineer, and WILLIAM MEAD of 12, Lucy Street, Lower Brough-
ton, Manchester, in the County of Lancaster, Engineer, do hereby declare the nature of
this invention to be as follows;-
Our invention relates to switches for starting and controlling electric motors,
and has reference to the regulation of rheostats for that purpose.
In order that our invention may be clearly understood we have appended the
accompanying two sheets of drawings, in which Figure 1, Sheet 1 is a sectional
elevation, and Figure 2 a plan view of our said invention, and Figure 3, Sheet 2,
is a sectional elevation of a modification thereof, and Figure 4 a plan view corre-
sponding thereto. Similar letters of reference indicate like parts throughout the
several views where practicable.
In carrying our invention into effect, we employ a central spindle A fixed to
the base B, the contact bar a and quadrant or wheel d moving thereon.
Said contact bar a is attached to a cylindrical box & containing a spiral spring c,
one end of which is attached to the spindle A and the other to the inside of the
box . The tension of the spring e tends at all times to return the contact bar a
to its normal position, which is that of starting the motor to which the switch is
adapted. A bevel wheel, or quadrant is attached to, or forms part of said box b
into the teeth of which a pinion e mounted upon a spindle s is caused to engage.
A handle H attached to said spindle s operates the contact bar a through the
bevel gearing d, e. The spindle s passes through the core of an enclosed electro
magnet preferably of the type known as "Pot" magnet, the armature g of which
is attached thereto. Said spindle s is telescoped so that the part carrying the pinion e
may have sufficient end play to keep said pinion out of gear with d normally, by
the tension of a spiral spring p contained within the mounting, which, as afore-
said, is formed by the hollow core or centre of the magnet f.
the
In the action of switching on the current to the electric motor, pressure upon
handle H and subsequent rotation, causes pinion e to engage with the wheel d
and the contact bar to make contact, and the electro magnet f becomes energized
by reason of its coils being in series with the field of the motor; and its armature g
then holds the pinion e in gear, so that further rotation may cut out the starting
resistance imposed by the rheostat device between the switch plates n or contacts.
If the current should fail by any cause, the pinion e is forced back by the spring P,
and the quadrant or the like being thus released, is returned to the starting
position by the spring c.

page_text: The modification shown by Figures 3 and 4 Sheet 2, is also designed to procure
an automatic release, and return to normal position, as herein before referred to.
The central spindle A carries the contact bar a which is fixed upon a box b
within which is a spiral spring c, one end of which is attached to the box and the
other to the upper box 6 which is extended by a boss into 6 for that purpose. A
flexible coupling is thus formed between the two boxes b and 6. The upper
box also contains a spring c¹ having one end of said spring attached to it, and
the other end to the spindle A which is fixed to the base B, so that it cannot
rotate. This spring is the main spring of the switch and tends at all times to
Lring the contact bar a into the starting position.
To the upper box is fixed a ratchet wheel into the teeth of which two pawls d
and e engage; d is pivotted upon a fixed pillar or stud k, and its function is to
prevent the ratchet wheel » moving backwards. The other pawl e is pivotted upon
an arm 1 oscillating about the spindle A, and carrying a handle H at its outer
end. This handle I being given a reciprocating motion, the teeth on the wheel
are successively taken up and pushed forward by the pawl e. A portion of the
wheel is blank, and has no teeth cut in it so that when it has turned sufficiently
to move the contact bar a to the last stud, the moving pawl e has no more teeth
to take up.
Even when the wheel is thus turned to the limiting position the
contact bar a may be brought to rest at any point within the regulating range
by means of a moveable stop E of insulating material, controlled by a handle H¹,
and checked by a stop plate q. Said moveable stop is suitably insulated, or is
made of insulating material, the difference in angle through which it is turned
being taken up in the flexible coupling b₁ herein before described, and the whole
is mounted on the central spindle A by the lower box b.
There are preferably two contacts n n¹ being respectively below and above the
contact arm a respectively, and suitable spring contacts are attached to the
arm a to engage with both of them as shown by the sectional view Figure 3.
The handle H, on the ratchet arm D can be rotated on its own axis, its spindle
having a figure piece i attached to it at the lower end, which engages with a
Y-shaped lever the opposite end of which is curved so as to lift both pawls d
and e out of engagement with the teeth of the wheel r simultaneously these pro-
jecting below said wheel for that purpose.
Thus, in switching on, the reciprocating movement of II and its spindle u feeds
the wheel step by step towards the desired point of connection between the motor
and the rheostat, but switching off is effected by twisting the handle H upon its
own axis centre in a clockwise direction, thus releasing both pawls & and e by
means of the finger piece i and lever j, after which the main spring c¹ in the box b
carries the contact arm a back to the starting point.
When an automatic release is required, we arrange a spring (not necessarily
shown in the drawings) which normally presses the curved end of the lever j
against the pawls, disengaging them from the teeth of the wheel r. An electro
magnet G, the coils of which are in series with the field of the motor, has a pivotted
armature K, connected by a rod to j so that whilst the current is passing through
the motor field circuit, the pawls & and e engage with the teeth of the wheel,
but when said current is interrupted, the armature K ceases to hold the lever j in
position and said pawls are thus withdrawn from the wheel r. The main spring c
then returns the contact arm a to the starting position.
It is understood that an ordinary switch is included in the circuit, and the switch
forming the subject of our invention controls the rheostat and its interposed con-
nections between the main circuit and the motor, for the purpose of regulating
the speed thereof.
Dated this 23rd day of Tanu 1800
FREDK. WALKER.
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Switches for Starting and Controlling Electric
Motors.
We, HUGO HIRST, of 69-71-88-92, Queen Victoria Street, in the City and County of
London, Electrical Engineer, and WILLIAM MEAD of 12, Lucy Street, Lower Brough-
ton, Manchester, 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:-
Our invention relates to switches for starting and controlling electric motors,
and has reference to the regulation of rheostats for that purpose.
In order that our invention may be clearly understood we have appended to our
Provisional Specification two sheets of drawings, in which Figure 1, Sheet 1 is a
sectional elevation, and Figure 2 a plan view of our said invention, and
Figure 3, Sheet 2 is a sectional elevation of a modification thereof, and Figure 4 a
plan view corresponding thereto. Similar letters of reference indicate like parts
throughout the several views where practicable.
In carrying our invention into effect, we employ a central spindle A fixed to
the base B, the contact bar a and quadrant or wheel d moving thereon.
Said contact bara is attached to a cylindrical box b containing a spiral spring c,
one end of which is attached to the spindle A and the other to the inside of the
box . The tension of the spring e tends at all times to return the contact bar a
to its normal position, which is that of starting the motor to which the switch is
adapted. A bevel wheel, or quadrant d is attached to, or forms part of said box b
into the teeth of which a pinion e mounted upon a spindles is caused to engage.
A handle attached to said spindle s operates the contact bar a through the
bevel gearing, v. The spindles passes through the core of an enclosed electro
magnet f preferably of the type known as "Potmagnet, the armature g of which
is attached thereto. The spindles is telescoped so that the part carrying the pinion e
may have sufficient end play to keep said pinion out of gear with d normally, by
the tension of a spiral spring p contained within the mounting, which, as afore-
said, is formed by the hollow core or centre of the magnet, f.
In the action of switching on the current to the electric motor, pressure upon the
handle H and subsequent rotation, causes pinion e to engage with the wheel d
and the contact bar to make contact, and the electro magnet f becomes energized
by reason of its coils being in series with the field of the motor; and its armature g
then holds the pinion e in gear, so that further rotation may cut out the starting
resistance imposed by the rheostat device between the switch plates n or contacts.
If the current flowing should fail by any means or cause, the tension of the
spring becomes active by the consequent loss of power of the magnet f, and the
pinion e is drawn out of gear, thus releasing the quadrant or the like which is
returned to the starting position by the coiled spring c.
12
The modification shown by Figures 3 and 4 Sheet 2, is also designed to procure
an automatic release, and return to normal position, as hereinbefore referred to.
The central spindle A carries the contact bar a which is fixed upon a box b
within which is a spiral spring, one end of which is attached to the box and the
other to the upper box which is extended by a boss into 6 for that purpose. A
flexible coupling is thus formed between the two boxes 6 and 6. The upper
box also contains a spring c¹ having one end of said spring attached to it, and
the other end to the spindle A which is fixed to the base B, so that it cannot
rotate. This spring is the main spring of the switch and tends at all times to
bring the contact bar a into the starting position.
To the upper box is fixed a ratchet wheel into the teeth of which two pawls d
"

page_text: and e engage; dis pivotted upon a fixed pillar or stud k, and its function is to
prevent the ratchet wheel r moving backwards. The other pawl e is pivotted upon
an arm D oscillating about the spindle A, and carrying a handle H at its outer
end. This handle H being given a reciprocating motion, the teeth on the wheel >
are successively taken up and pushed forward by the pawl e. A portion of the
wheel r is blank, and has no teeth cut in it so that when it has turned sufficiently
to move the contact bar a to the last stud, the moving pawl e has no more teeth
to take up. Even when the wheel is thus turned to the limiting position the
contact bar à may be brought to rest at any point within the regulating range
by means of a moveable stop E of insulating material, controlled by a handle H,
and checked by a stop plate q. Said moveable stop is suitably insulated, or is
made of insulating material, the difference in angle through which it is turned
being taken up in the flexible coupling herein before described, and the whole
is mounted on the central spindle A by the lower box b.
There are preferably two contacts n n¹ being respectively below and above the
contact arm a respectively, and suitable spring contacts are attached to the
arm a to engage with both of them as shown by the sectional view Figure 3.
The handle H, on the ratchet arm D can be rotated on its own axis, its spindle
having a finger piece attached to it at the lower end, which engages with a
Y-shaped lever j the opposite end of which is curved so as to lift both pawls d
and e out of engagement with the teeth of the wheel simultaneously these pro-
jecting below said wheel r for that purpose.
Thus, in switching on, the reciprocating movement of H and its spindle u feeds
the wheel step by step towards the desired point of connection between the motor
and the rheostat, but switching off is effected by twisting the handle H upon its
own axis centre in a clockwise direction, thus releasing both pawls d and c by
means of the finger piece and lever j, after which the main spring c in the box bi
carries the contact arm back to the starting point.
When an automatic release is required, we arrange a spring (not necessarily
shown in the drawings) which normally presses the curved end of the lever j
against the pawls, disengaging them from the teeth of the wheel r. An electro
magnet G, the coils of which are in series with the field of the motor, has a pivotted
armature K, connected by a rod to so that whilst the current is passing through
the motor field circuit, the pawls and e engage with the teeth of the wheel ¹,
but when said current is interrupted the armature K ceases to hold; the lever j in
position and said pawls are thus withdrawn from the wheel r.. The main spring c
then returns the contact arm a to the starting position.
It is understood that an ordinary switch is included in the circuit, and the switch
forming the subject of our invention controls the rheostat and its interposed con-
nections between the main circuit and the motor, for the purpose of regulating
the speed thereof.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
First. In a switch for use with rheostats for starting and controlling electric
motors, the combination and arrangement of a spring box or boxes, with a feed and
release device whereby a return may be effected by hand or automatically, sub-
stantially as and for the purposes herein set forth with reference to the appended
drawings.
Second. In a switch for starting and controlling electric motors, the combination
of a spring c box b, wheel and pinion de with an electro magnet f, the armature
of which acts upon the pinion e substantially as and for the purposes described
with reference to Figures 1 and 2 of the appended drawings.
Third. In a switch for starting and controlling electric motors, the combina-
tion of a switch arm and contacts with a ratchet wheel r, boxes bb and springs cc¹,
pawls de and reciprocating arm D, having a releasing movement i j substantially

page_text: as herein described and for the purposes set forth with reference to Figures 3
and 4 of the appended drawings.
Fourth. In a switch for starting and controlling electric motors as referred to
in the preceding claim the method of and means for effecting an automatic electrical
release of the pawls de substantially as herein described and shown by the
appended drawings.
Fifth. In a switch for starting and controlling electric motors, as referred to
in the two preceding claims, the construction and use of an adjustable insulated
stop E, substantially as and for the purposes herein described, and shown by
Figures 3 and 4 of the appended drawings."
Datad this 20th day of War 1800
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant.