Improved Means or Apparatus for Reversing and Regulating the Brushes of Dynamo Electric Machines, Partly Applicable to Electric Motors.
Year: 1888

page_text: Date of Application, 13th Nov., 1888
Complete Specification Loft, 13th Aug, 1000 Accented 28th Sent 1889
PROVISIONAL SPECIFICATION.
Improved Means or Apparatus for Reversing and Regulating the
Brushes of Dynamo Electric Machines, Partly Applicable to
Electric Motors.
I, JOHN SMITH RAWORTH of 112 Belvedere Road Lambeth in the County of
Surrey Engineer, do hereby declare the nature of this invention to be as follows:-
A Dynamo electric machine fitted with my improved reversing and regulating
apparatus may be driven in either direction and at varying speeds, the function of
such apparatus being to place the brushes in the proper position on the commutator
according to the direction of rotation, and to adjust that position to suit alterations in
-speed.
Apparatus according to my invention is particularly applicable to dynamos driven
by the axles of railway vehicles. It is also suitable for adjusting the positions of the
brushes of an electric motor as the speed of such motor varies.
According to my invention one or more pairs of brushes are carried by spindles
or shafts projecting from a rocking frame or lever. Each of these spindles or shafts
is provided with a small crank or lever arm having a projecting pin, and springs or
weights are provided to keep the rocking frame and the spindles carrying the brushes
in a middle or central position. A fan driven by the dynamo spindle and provided
with radial vanes or blades is arranged to revolve in a casing also provided with vanes
or blades and filled with liquid. The fan in revolving tends to carry with it the
A double
casing which is supported in a bearing that permits of circular motion.
ended lever in connection with the casing engages the pins carried by the herein before
mentional crank or lever arms.
The arrangement is such that when the dynamo commences to revolve in either
direction the fan acting upon the liquid in the casing causes the double ended lever
in connection with such casing to overcome the action of the springs or weights which
hold the brushes in the middle position, and to force the brushes into contact with
the commutator and in proper position according to the direction of rotation of the
dynamo. Stops are provided to prevent the pressure on the brushes being increased
unnecessarily. As the speed continues to increase, the double ended lever overcomes
the action of the springs or weights and carries the rocking frame or lever forward
sufficiently to adjust the lead of the brushes corresponding to the increase of
speed.
By adjusting the strength of the springs, or equivalent, or the size of the vanes or
blades, the brushes may be arranged to make contact with the commutator at any
desired speed of the armature.
The arrangement of levers and pins may be modified by the use of pinions and
toothed wheels or segments or by pulleys and cords.
The same result though in an inferior degree may be obtained by substituting a
simple friction device for the fan and casing as for instance by using a pulley in
place of the fan and a double clip with leather liners in place of the casing.
Where it is desirable to excite the magnets of the dynamo from an independent
source as for instance from accumulators, a contact making device may be arranged
to be actuated by the fan casing and regulated to close the circuit when the speed of
the dynamo has risen to any desired rate of rotation.
In applying means or apparatus according to this invention to motors, similar
arrangements may be used, parts not required for the particular purpose to which
the motor is to be applied, being omitted according to circumstances.
Dated this 18th day of November 1888.

page_text: "
COMPLETE SPECIFICATION.
Improved Means or Apparatus for Reversing and Regulating the
Brushes of Dynamo Electric Machines, Partly Applicable to
Electric Motors.
1, JOHN SMITH RAWORTH, of 112 Belvedere Road, Lambeth, in the County of
Surrey, Engineer, lo 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 :—
I
A dynamo electric machine fitted with my improved reversing and regulating
apparatus may be driven in either direction and at varying speeds, the function of
such apparatus being to place the brushes in the proper position on the commutator
according to the direction of rotation, and to adjust that position to suit alterations in
speed.
Apparatus according to my invention is particularly applicable to dynamos driven
by the axles of railway wheels. It is also suitable for adjusting the positions of the
brushes of an electric motor as the speed of such motor varies.
According to my invention one or more pairs of brushes are carried by spindles,
shafts, or brush holders projecting from and carried by a rocking frame or lever. Each
of these spindles or shafts is provided with a small crank or lever arm having a
projecting pin, and springs or weights are provided to keep the rocking frame and
the spindles carrying the brushes in a middle or central position A fan driven by
the dynamo spindle and provided with radial vanes or blades is arranged to revolve in
a casing also provided with vanes or blades and which may be filled with liquid. The
fan in revolving tends to carry with it the casing which is supported in a bearing that
permits of circular motion. A lever in connection with the casing engages the pins
carried by the hereinbefore mentioned crank or lover arms.
The arrangement is such that when the dynamo commences to revolve in either
direction, the fan acting upon the liquid in the casing causes the lever in connection
with such casing to overcome the action of the springs or weights which hold the
brushes in the middle position, and to force the brushes into contact with the commu-
tator and in proper position according to the direction of rotation of the dynamo.
Stops are provided to prevent the pressure on the brushes being increased
unnecessarily.
As the speed continues to increase, the lever in connection with the casing over-
comes the action of the springs or weights and carries the rocking frame or lever
forward sufficiently to adjust the lead of the brushes corresponding to the increase of
speed.
By adjusting the strength of the springs, or equivalent, or the size of the vanes or
blades, the brushes may be arranged to make contact with the commutator at any
desired speed of the armature.
For the arrangement of levers and pins may be substituted pinions and toothed
wheels or segments, or pulleys and cords.
The same result though in an inferior degree may be obtained by substituting a
simple friction device for the fan and casing, as for instance by using a pulley in
place of the fan and a double clip with leather liners in place of the casing.
Where it is desirable to excite the magnets of the dynamo from an independent
source as for instance from accumulators, a contact making device may be arranged
to be actuated by the fan casing and regulated to close the circuit when the speed of
the dynamo has risen to any desired rate of rotation.
In applying means or apparatus according to this invention to motors, similar
arrangements may be used, parts not required for the particular purpose to which the
motor is to be applied being omitted according to circumstances.
Referring to the accompanying three sheets of drawings
Fig. 1 is a side elevation partly in longitudinal vertical section.
Fig. 2 is an end elevation partly in transverse vertical section; and
Fig. 3 is a plan of my improved reversing and regulating annaratna.

page_text: Similar letters refer to similar parts in all cases.
1, 1 are brushes carried by brush holders 2 that are insulated from and are free to
move on pins or rods 3 projecting from a rocking frame or lever 4.
5,5 are crank arms carried by the brush holders; they serve to move such holders
upon the pins or rods 4.
6 is a spring that acts upon the frame or lever 4; it is double ended and is connected
to two adjustable levers 7 carried by the brush holders. These levers each take a
bearing against a stop 8 carried by the frame or lever 4 and it is only when the levers 5
commence to move in either direction from a central position that these levers move
one or other of the levers 7 from its fixed position and thereby increase the tension
on the spring 6. The levers 7 are each made in two parts jointed together as shown
to allow the tension on the spring 6 to be easily adjusted by hand, and also to allow of
the amount of the leverage being easily adjusted.
9 is a fan provided with radial vanes; it revolves in a casing 10 also provided with
radial vanes.
10 is a lever secured to the casing 10 and connected by links 10b with
the arms 5.
When the fan 9 revolves in either direction it tends to carry with it the
casing 10. The extent of motion of the casing is limited by one or other of two
arms 11, 11 coming in contact with a stop or magnet bobbin 12 which is carried on
an extension of the frame 4, the arrangement being such that when the casing 10 is
moved, it first applies one or other set of brushes to the commutator, and when it has
attained the limit of its notion with regard to the frame 4 the two are still free to
move together, this second motion being for the purpose of adjusting the positions of
the brushes upon the commutator as circumstances may require. The tendency for
this frame 4 to move from its central position is resisted by springs 13.
Nozzles are provided at 14, 15 for establishing a circulation of water through the fan
casing if necessary.
The stop 12 carried by the frame 4, may with advantage be made an electro
magnet, (as shewn) traversed by the main current, so that when either of the arms 11
come in contact with one or other of its ends the tendency of the magnet is to retain
such stops firmly in position and prevent chattering of the brushes.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
The combination of parts substantially as hereinbefore described and as illustrated
in the accompanying drawings for the purposes set forth.
Dated this 13th day of August 1889.
W. LLOYD WISE,
Per F. J. B.,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.