Improved Automatic Coupling for Electromotors.
Year: 1895

page_text: Date of Application, 29th Jan., 1895-Accepted, 6th Apr., 1895
[Communicated from abroad by Messrs.. SIEMENS & HALSKE, of Berlin, in the.
German Empire, Electrical Engineers.]
Improved Automatic Coupling for Electromotors.
We, SIEMENS BROTHERS & Co., LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, Electrical Engineers, 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 :-
In the Specification to Patent No. 16025 of 1893 was described an automatic
coupling for electromotors, in which the armature shaft was shifted longitudinally
against the action of a spring when the motor was put in circuit, and thereby
caused a half coupling thereon to engage with a half coupling on the shaft to be
driven.
This arrangement has the disadvantage that on the coupling being effected, the
increased resistance causes the strength of the field magnets to decrease, thereby
the spring acting on the armature shaft is enabled to push this back again.
This is liable to produce concussions which act detrimentally on the coupling.
According to the present invention this is obviated by combining with the
armature shaft a lever so arrauged that when the shaft is shifted for engaging the
coupling the lever brings a soft iron armature connected thereto against the field
magnet poles or against the poles of a separate electromagnet included in the
circuit which magnet consequently holds the lever and clutch in the engaged
position so long as current is passing, notwithstanding any fluctuation that may
occur in the strength of the magnets.
The accompanying drawing shews an electro motor with the above described
improved automatic coupling applied thereto.
Figs. 1 and 2 shew respectively a side elevation and end view with the parts in
the uncoupled position. Figs. 3 and 4 shew similar views with the parts in the
coupled position. Fig. 5 shews a side view and end view of the coupling
detached.
The armature shaft S carries the half coupling C which, in the position at Fig. 1
is disengaged from the half coupling C¹ on the shaft S', while in the position
at Fig. 3 the two half couplings are engaged. In this arrangement the electro-
motor being in a vertical position, the downward motion of the armature for
disengaging the coupling is effected by gravity thus dispensing with spring action,
while the attraction of the field magnets when excited by current causes it to rise
into the engaged position. To a bracket on the motor is pivotted an elbow lever H,
one arun of which is engaged by means of a fork with the end of the armature
shaft S, while the other arm carries a soft iron armature A.
When the motor is put in circuit and thereby raises the armature_shaft so as to
engage the coupling, the lever H is moved from the position at Fig. 1 into the
position at Fig. 3, bringing the armature A in contact with the polar extensions
of the field magnets, which thus hold the lever and armature in that position so long
as the motor is in circuit.

page_text: Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, we declare that what we
claim is:
In an automatic coupling for electro motors wherein the armature shaft is
moved longitudinally for engaging the coupling when the motor is put in circuit,
the combination with the armature shaft of a supplemental armature so arranged
that the motion of the armature shaft causes it to be applied either to the pole
pieces of the field magnets, or to a separate electromagnet so as to hold the shaft
and coupling in the engaged position so long as the motor is in circuit, substantially
as described.
Dated this 29th day of January 1895.
ABEL & IMRAY,
Agents for the Applicants.