An Improved Electro-magnetic Friction Clutch.
Year: 1894

page_text: Date of Application, 13th Sept., 1894
Complete Specification Left, 13th June, 1895-Accepted, 13th July, 1895
PROVISIONAL SPECIFICATION.
An Improved Electro-magnetic Friction Clutch.
I, WALTER CHARLES BERSEY, of 59, Gore Road, South Hackney, London, E..
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
:―
My invention relates to friction clutches for the transmission of rotary motion
which are adapted to be thrown in and out of operative engagement and so main-
tained by means of electro-magnetic action, and it consists essentially in mounting
upon each half of the clutch a number of electro magnets so arranged that when
the magnets are energized by the passage of a current the poles of all those in one
half of the clutch shall simultaneously face those of opposite polarity, and by
their mutual attraction cause the one part of the clutch to be moved into frictional
driving contact with the other part of the clutch and maintain the parts in
operative engagement so long as the current is passing.
In a clutch constructed according to my invention the halves consist each of a
chambered disc-shaped drum of dia-magnetic material such as gun-metal mounted
upon the shaft to be driven, the one half running free on the shaft whilst the
other half is so attached thereto as to be capable of transmitting rotary motion
and of sliding longitudinally upon the shaft sufficiently to enable the parts to he
thrown in and out of gear. Each disc carries a number of horseshoe electro-
magnets whereof the cores pass through the disc from side to side and carry the
usual coils in the chamber of the disc the polar extremities of the cores being
flush with the friction driving surface whilst the outer ends are connected by
suitable yoke pieces which may be countersunk in the outer face of the disc.
The coils are connected with insulated gun-metal rubbing rings, countersunk in the
periphery of each disc, the brushes which transmit the electrical current being
arranged to bear against the exposed surfaces of the rings. The poles of the
magnets in each half of the clutch are equidistant and in alternate order, so that
when the poles of the magnets in the driving half face those of opposite polarity
in the driven half the latter will be moved by magnetic attraction into frictional
driving contact with the driving half and there maintained so long as the current
continues to pass.
Dated this 13th day of September 1894.
1, WALTER CHARLES BERSEY, of Grosvenor House, Gore Road, South
Hackney, London, E. Electrical 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 :-
My invention relates to friction clutches for the transmission of rotary motion❤

page_text: which are adapted to be thrown in and out of operative engagement and so main-
tained by electro-magnetic action, the clutch being specially intended for the
driving gear of electrically propelled vehicles. It consists of a friction clutch
each half of which is provided with a number of electro-magnets which by their
mutual attraction when energized by the passage of a current will cause the one
part of the clutch to be moved into contact with the other part of the clutch, the
magnets being so arranged that the poles of all those in one half of the clutch
will at given points in the revolution simultaneously face those of opposite
polarity, so that once the frictional driving contact between the parts is sufficient
to overcome the resistance the two parts of the clutch will be maintained in
operative engagement so long as the current is passing.
In the accompanying. drawings, forming part of this Specification, I have
illustrated a clutch constructed according to my invention, Figure 1 being a section
of the clutch, on line 1-1 Figure 2 which is an inside face view of one member of
the clutch.
A, B, are the two halves of the clutch, each of which consists of a chambered:
disc-shaped drum of dia-magnetic material such as gun-metal mounted upon the
shaft C to be driven, the one half A running free on the shaft whilst the other
half B is mounted in close proximity to the half. A upon the shaft to which it is
attached by groove, and feather connection so as to be capable of transmitting.
rotary motion to the shaft and of sliding longitudinally thereon sufficiently to
enable the parts A, B, to be thrown in and out of driving engagement. Each
drum carries a number of horseshoe electro-magnets N, S, whereof the cores c pass
through the drum from side to side and carry the usual coils d in the chamber of
the drum, the polar extremities N, S, of the cores being flush with the friction.
driving surface formed by a cover plate D also of gun-metal, whilst the outer ends
of the cores are connected by suitable yoke pieces e which may be countersunk in
the outer face of the drum. The coils d of each half of the clutch are connected
in series. and with gun-metal rubbing rings E, F, countersunk in, grooves in the
periphery of each half and insulated therefrom by a. bed of fibre or other suitable
insulating material, the brushes which transmit the electrical current being carried.
by any suitable support and arranged to bear against the exposed surfaces of the
rings E, F. The poles N, S, of the magnets in each half of the clutch are
equidistant from each other and in alternate order and at the same radial distance
from the axis of the clutch in both halves so that when the poles of the magnets
in the driving half A come nearly opposite those of opposite polarity in the
driven half B the latter will be moved by magnetic attraction. into contact with, the
driving half and be set in motion thereby.
The resistance to be overcome might at first be too great to admit of; the part B.
at once acquiring the same velocity as the part A in which case a certain. amount.
of slip would occur, the magnetic attraction being renewed each time that
different poies become opposed in the two halves of the clutch until finally on the
same velocity being attained by the two parts A, B, their operative contact would
be maintained uninterruptedly so long as the conditions, remain unchanged.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
The herein described electro-magnetic friction clutch constructed to operate
substantially as specified.
Dated this 13th day of June 190
A. M.. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.