Improvements in Electromagnetic Clutches.
Year: 1897

page_text: Date of Application, 12th Oct., 1897-Accepted, 13th Nov., 1897
[Communicated from abroad by THE SINGER INDUSTRIAL COMPANY of New York
in the State of New York United States of America]
Improvements in Electromagnetic Clutches.
I, WILLIAM GEORGE HEYS, of 70 Market Street, Manchester, in the County of
Lancaster, Chartered Patent Agent, 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 means for transmitting power to a machine located
inside of a sealed chamber without creating openings through the walls of the
chamber.
Where pumps or blowers are used to move a fluid or a wody of gas or a mixture
of gases other than atmospheric air, the air must be placed inside of a hermeti-
cally sealed casing in order to prevent the escape of the gas, fluid, or the like which
is being treated. To transmit power to such a machine from a source of power
located outside of the casing necessitates making an opening through which the
shaft may be passed, but it has been found in practice that although the shaft
bearing may be packed as perfectly as possible, the bearing soon wears sufficiently
to allow the gas to escape. Electric motors have been placed bodily in the gas
chamber and coupled direct to the pump or blower, but an objection is found to
this practice in the fact that if the gas be an explosive gas the sparks from the
motor may cause an explosion, or, if the gas be not of an explosive nature, the
heat naturally generated by the motor may injure the gas or raise its temperature
to an undesirable point.
In accordance with this invention, the pump, blower or other machine confined
in the sealed chamber, is driven from an external source of power without making
any openings whatever in the walls of the chamber. This is accomplished by
using an electromagnetic coupler in the manner hereinafter particularly described.
In the accompanying drawing, which is hereinafter referred to, the Figure
represents a section through the casing of a gas blowing machine, showing the
blower therein in side elevation, and also illustrating in side elevation the power
transmitting apparatus.
represents a hermetically sealed casing which contains, or through which
passes a gas or liquid. In this chamber is placed a pump or blower of any suitable
character such as a shaft a carrying a set of blades and mounted in suitable
bearings. Any other machine may be located in this casing and driven in the
manner hereinafter described, the shaft a representing the shaft of any such
meline. On the end of the shaft a is mounted a cross-head of soft iron con-
stituting the armature of an electro-magnet as will hereinafter appear.
extremities of this armature are preferably bent or returned at substantially right
angles to the cross head to form polar faces a. These polar faces stand close to
the surface of one of the walls of the gas-tight chamber, and this wall is formed
with a cylindrical inward projection a passing into the embrace of the armature,
and around the periphery of which the armature may rotate with just sufficient
The

page_text: clearance to prevent contact. The wall or diaphragm of which the cylinder e is
a part, is of non-magnetic material such as brass, brenze, or possibly glass.
At one
Outside of the chamber A a shaft is mounted in suitable bearings and carries
a pulley e. This shaft is preferably in line with the shaft in the case.
end it carries a horse shoe electro-magnet consisting of a core and a pair of
coils The poles of the core pass into the cylinder o and face towards the inner
cylindrical surface at diametrically opposite points. The shaft E is hollow and
the wires and 2 lead from a suitable source of electricity through the shaft to
the coils f'.
It will be seen that when the armature inside of the casing A is standing in
the position shown in the drawing with relation to the poles of the magnet, it
closes the magnetic circuit of the magnet except for the small air gaps and the
non-magnetic plate e between the polar faces, consequently there will he a magnetic
attraction between the core of the magnet and the armature which may be of such
strength as to cause the armature to follow or rotate with the core whenever the
core is rotated. So that if power be transmitted to the shaft E from an engine,
electro-motor, or other suitable source by a belt to pulley c', substantially the same
power will be transmitted through the magnetic coupler described, to the pump,
blower, or other machine inside of the casing A, and the machine is thus driven
from an external source of power without creating any openings in the casing and
without liability of causing leaks. The anes of force passing between the magnet
and the armature are substantially radial in direction, consequently no end thrust
is imparted to either shaft. This is the preferred construction, but the polar faces
may be arranged at right angles to the shafts if desired.
If desired, an electro-motor may be coupled direct to the shaft E in which case
the pulley might represent the armature of the motor, but this is an uninpor-
tant feature, the principal element being the means for coupling the power shaft
with the shaft to be driven.
The use of a permanent magnet for the coupler is disclaimed, inasmuch as such
an apparatus is entirely inefficient and impracticable for transmitting largo
powers, and even if it were possible to use a permanent magnet to transmit largo
powers the use of an electro-magnet would still be preferred for the reason that it
is possible to vary the power of the clutch either manually or automatically by
varving the current permitted to pass through it, and in this way utilise the
coupler or clutch as a safety or regulating appliance to prevent the overloading of
the driving motor, and also to economise in the power consumed in the clutch.
Another important difference between a permanent magnet, and an electro-
magnet in the transmission of power is that a permanent magnet is merely the
equivalent of an ordinary mechanical coupler which cannot be used to uncouple
the members, whereas with un electromagnet, a perfect clutch capable of
uncoupling as well as coupling is obtained.
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. The combination with a blower or other machine situated within a hermetic-
ally sealed casing, of an external electromagnetic coupler, constructed arranged
and operating substantially as and for the purpose hereinbefore set forth and as
illustrated by the accompanying drawing.
2. The combination of a hermetically scaled case, a machine therein having a
main rotating shaft to be driven, a driving motor and its rotating shaft located
outside of said casing, an electromagnetic clutch having its two members mounted
respectively on the two rotating shafts, one member being inside the casing and
the other outside thereof, whereby the clutching and unclutching of the two
rotating shafts may be effected through an unperforated wall of the casing, all
constructed arranged and operating substantially as hereinbefore described and as
illustrated by the accompanying drawing.

page_text: 3. An electromagnetic coupling device, constructed arranged and operated sub-
stantially as and for the purpose set forth and as illustrated by the accompanying
drawing.
1000
W. E. HEYS & SON,
Agents for the Applicant.