Improvements in Magnetic Brakes.
Year: 1898

page_text: Date of Application, 28th Oct., 1898-Accepted, 14th Jan., 1899
Improvements in Magnetic Brakes.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby
declare the nature of this invention (which has been communicated to me from
abroad by the Elektrizitäts-Aktiengesellschaft vormals Schuckert & Co., of Nürn-
berg, in the Empire of Germany) and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement;-
In magnetic brakes now in use a brake block is, by means of
magnetic attraction, pressed against a disc fixed to the axle to which
the brake is to be applied. The braking action is obtained partially
by the Foucault currents produced in the brake disc, principally how-
ever by means of mechanical friction. The rubbing surfaces may
be at right angles to the axle or may peripherally surround the latter in the form
of segments. It is usual to form that portion of the brake from which the lines
of force radiate to complete a circuit through the said brake disc, in one with
the bobbin carriers. In the magnetic brake shown in the accompanying drawings,
the portion a from which the flow of the lines of force passes to the brake disc b,
and the bobbin carrier c form separate elements of construction, which are SO
formed that the pole piece forming the friction block or shoe a can slide in a
steel ring within the bobbin carrier c, which ring may be changed when worn.
The advantage of this construction is that the friction shoe or block may be
easily and cheaply changed, and that the magnet winding is fixed, which
arrangement materially contributes to the security of the conductor connections
and to the insulation of the winding.
The arrangement of magnetic brake according to this invention possesses a
certain outward resemblance to a two or multi polar dynamo machine with cased
in poles, in which however the polar shoes or blocks are arranged, (regard being
had to the above mentioned insufficiency of the braking action of the Foucault
currents alone), to move axially in order to obtain direct contact with the brake
disc. The magnetic lines pass, as shown by the dotted line in Figure 1, through
the polar piece forming the shoe or block into the brake disc and return through the
bobbin carrier, which form a closed circuit for all bobbins of two or multipolar
brakes, thus a further advantage is obtained in that the casing necessary for the
exclusion of dust and water to the brake, utilized for conducting the lines of
force.
In order to prevent the transfer of the lines of force from the brake disc to the
axle and the prejudicial action consequent upon the dispersal of the lines of force
and to render possible their return to the pole producing them, a non magnetic
material m is interposed at a suitable point in this prejudicial path.
The friction shoes or blocks arranged moveably within the bobbin carriers are
preferably held away from the brake disc by means of a spring as soon as the
brake is out of action, that is to say, when without current.
The brake apparatus is hung in the usual manner by means of a lever screwed

page_text: to or cast with the same, which lever is flexibly connected at its free end with a
fixed portion of the car.
1
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to-be performed I declare that what I
claim is
1. Magnetic brakes in which the magnetic system is arranged inside a polar
casing, similar to a dynamo frame, and in which the pole pieces forming the
friction blocks or shoes are arranged to be moveable axially for the purpose of
obtaining frictional action, upon the brake dise: rotating between the same, in
such a manner that the lines of force are conducted through the friction blocks
or shoes to the brake disc...
2. Magnetic brakes substantially as
panying drawings.
4:1
24271
ليوم
-B
000
described and illustrated in the accom-
I PORT
Dated this 28th day of October 1898.
...
..SYDNEY PITT.