An Improvement in Commutator Brushes for Electrical Machines.
Year: 1899

page_text: Date of Application, 31st Jan., 1899-Accepted, 1st Apr., 1899
COMPLETE SPECIFICATION.
An Improvement in Commutator Brushes for Electrical Machines.
We, SIEMENS BROTHERS & Co. LIMITED, of 12, Queen Anne's Gate, West-
minster, in the County of London, Electrical Engineers, and ALEXANDER SIEMENS,
of same address, Civil 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:
This invention relates to a construction of the commutator brushes for an electric
generator or motor in such a manner that they can be readily adjusted, removed
and replaced, as will be described with reference to the accompanying drawings.
Fig. 1 is a transverse section of the brush holder and one of the brush sections,
Fig. 2 is a front elevation, part of the front being broken away at the left to shew
the brush section and its clamp, Fig. 3 is a plan.
In Figs. 2 and 3 only the end parts of the holder are shewn, it being understood
that there may be one brush, or any number of brush sections between these
extremes.
a is the main frame of the brush holder to which a front b is fixed by bolts c
with interposed distance pieces d which may be varied to suit different thicknesses
of brushes.
Each brush section e is a slab of carbon, or it might be a laminated plate of copper
or other suitable metal or of wire gauze.
Each section e is clamped between a vertical bar f and a bent blade-spring g
which has its upper end fixed to the head of the bar f. Through this head is
screwed the adjusting screw h the end of which bears on the top of the section c.
The bars fare guided to slide in vertical grooves formed in the front b, and behind
each of them in a recess of the front b is a helical tension spring i having its lower
end attached to the lower part of the front b and its upper end attached to a slotted
hook-plate which is hooked on to a nose k projecting from the head of the bar f.
On unhooking j from the nose k the brush section e along with the bar f spring g
and adjusting screw h can be removed bodily, the brush section e being still held
clamped between f and g. The whole, after inspection, or repair with a new
section e if required, can be replaced by merely pushing it down between a and b
and hooking on k. The end of the spring g has a V shaped bend which, on
pulling up the brush section, can engage in a notch provided in the frame holding
the brush section up when required. In order that the hook plate j may, when it
is unhooked, present itself in position ready to be hooked again, a notch is made
at each side of the recess which holds the spring i, to receive the lower edge of the
hook plate and hold it so that it can readily be taken hold of.
The frame a, which may be of any required length to take the desired number
of brush sections e, is bolted on a suitable support forming part of the framing of
the machine, and is provided with two bosses m for attaching a conductor the one or
the other of these being employed according as the brush holder is placed in right
or left handed position.

page_text: Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, we declare that what
we claim is :-
A commutator brush made in one or more sections fitted in a suitable frame
each section pressed by an adjustable spring on the commutator and separately
removable from the frame, substantially as described with reference to the
drawings.
Dated this 21st day of Tony 1900