Improvements in Methods and Apparatus for the Transmission of Power by Belts, Ropes, or Chains.
Year: 1890

page_text: Date of Application, 6th Oct., 1890
Complete Specification Left, 1st July, 1891-Accepted, 1ct Aug., 1891
PROVISIONAL SPECIFICATION.
Improvements in Methods and Apparatus for the Transmission of
Power by Belts, Ropes, or Chains.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23 Southampton Buildings, in the
County of Middlesex, Patent Agent, do hereby declare the nature of this invention,
a communication to me from abroad by Thomos Alva Edison, of Llewellyn Park,
in the County of Essex, and State of New Jersey, United States of America,
Inventor, to be as follows
The object of this invention is to produce a new mechanical movement by the aid
of magnetism, which will permit the positive transmission of large powers at high
velocity, without the excessive noise incident to the use of tooth gearing. This
is accomplished by the employment of smooth face iron pulleys or wheels, which
are made strongly magnetic by suitable windings connected in circuit with a
suitable source of electrical energy, and by the use of endless belts, chains, or
ropes, which are either themselves magnetic or carry iron bars (or both) which
form armatures to close the magnetic circuits at the pulleys and are strongly
attracted to the face of the pulleys so as to increase the adhesion and transmit
the power without slip; or the magnetic bars, instead of being carried directly
by the belts, chains, or ropes, may be arranged in a frame over the belt, chain, or
rope, where it passes around the pulley, and be capable of a movement towards
the pulley to a limited extent so as to press the belt, chain, or rope, upon the
pulley.
The invention is applicable in all cases where tooth gearing has heretofore been
employed. In particular, by reason of the great adhesion of the endless belt, chain,
or rope, to the pulleys or wheels, pulleys or wheels located very close together can
be thus connected, and a considerable reduction in speed can be effected by a single
endless belt, chain, or rope. The invention when applied in place of the gearing
connecting the driving electric motors with the axles of the cars, for electric
railways, overcomes very largely the difficulties which have heretofore been
experienced in this class of work.
The pulleys or wheels are constructed of iron, and are preferably made magnetic
by means of circumferential windings, one or more of such windings being placed
upon each pulley or wheel. The magnetic belts close the magnetic circuits around
these circumferential windings upon the face of each pulley or wheel, thus forming
a very short magnetic circuit and producing powerful magnetic effects.
Since the capacity to transmit power depends upon the conditions existing at the
smaller pulley or wheel where the surface of contact is less than at the larger pulley
or wheel, it is preferable to make the smaller pulley or wheel more strongly
magnetic than the larger one, thus not only increasing the magnetic attraction at
the smaller pulley, but also increasing the surface of contact between its face and the
belt, since the belt will be drawn over the face of the pulley on the slack side of the
belt and will cover a greater surface of the pulley.
The magnetic windings upon the pulleys or wheels terminate in insulated rings,
upon which bear springs, brushes, or other suitable devices for connecting the
windings with the source of electrical energy. Instead of having the magnetic
windings mounted in circumferential grooves upon the pulleys or wheels, by one
modification of the invention, these windings may be located in grooves passing
around the rim of the pulley or wheel and transversely across its face, or, where the
conditions will permit, the two iron pulleys or wheels, may be connected by an iron
rame which will carry the magnet winding, one pulley or wheel forming one pole
of the magnet and the other pulley or wheel forming the other pole of the magnet,

page_text: the poles being connected by the magnetic belt, rope, or chain. The magnetic belt
may be made of a number of steel strips placed one over the other and having upon
the outside cross bars of soft iron secured transversely to the steel strips by rivets
or otherwise, or one or more steel wire ropes may be employed, or a number of
steel wire ropes may be placed parallel and be connected by cross bars of iron,
through which the ropes will pass and to which they will be secured.
Instead of using a belt constructed of magnetic material, one of non-magnetic
material may be employed, and the magnetic bars may be constructed in the form
of rollers mounted in a frame located at each pulley and bearing upon the belt
where it is in contact with the pulley. These magnetic rollers will be loosely
journalled in the frame, and being attracted by the pulley will press the belt upon
it, thus increasing its adhesion.
Dated this cel
00
COMPLETE SPECIFICATION.
Improvements in Methods and Apparatus for the Transmission of
Power by Belts, Ropes, or Chains.
I BENJAMIN JOSEPH BARNARD MILLS of 23 Southampton Buildings in the
County of Middlesex Patent Agent do hereby declare the nature of the said
invention, a communication to me from abroad by Thomas Alva Edison of
Llewellyn Park in the County of Essex and State of New Jersey United States
of America Inventor, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
The object of this invention is to produce a new mechanical movement by the
aid of magnetism, which will permit the positive transmission of large powers at
high velocity without the excessive noise incident to the use of tooth gearing,
This is accomplished by the employment of smooth face iron pulleys, or wheels,
which are made strongly magnetic by suitable windings connected in circuit with a
suitable source of electrical energy, and by the use of endless belts, chains or ropes,
which are either themselves magnetic or carry iron bars (or both) which forin
armatures to close the magnetic circuits at the pulleys and are strongly attracted to
the face of the pulleys so as to increase the adhesion and transmit the power
without slip; or the magnetic bars, instead of being carried directly by the belts
chains or ropes, may be arranged in a frame over the belt, chain or rope where it
passes around the pulley, and be capable of a movement towards the pulley to a
limited extent so as to press the belt chain or rope upon the pulley.
The invention is applicable in all cases where tooth gearing has heretofore been
employed. In particular, by reason of the great adhesion of the endless belt, chain
or rope to the pulleys or wheels, pulleys or wheels located very close together can
thus be connected, and a considerable reduction in speed can be effected by a single
endless belt, chain or rope. The invention when applied in place of the gearing
connecting the driving electric motors with the axles of the cars, or electric
railways, overcomes very largely the difficulties which have heretofore been
experienced in this class of work.
The pulleys or wheels are constructed of iron and are preferably made magnetic
by means of circumferential windings, one or more of such windings being placed
upon cach pulley or wheel. The magnetic belts close the magnetic circuits around
these circumferential windings
a very short magnetic circuit and on the face of each pulley or wheel, thus forming
producing powerful magnetic effects,
Since the capacity to transmit power depends upon the conditions existing at the
smaller pulley or wheel where the surface of contact is less than at the larger pulley
or wheel, it is preferable to make the smaller pulley or wheel more strongly

page_text: magnetic than the larger one, thus not only increasing the magnetic attraction at
the smaller pulley, but also increasing the surface of contact between its face and
the belt, since the belt will be drawn over the face of the pulley on the slack side
of the belt and will cover a greater surface of the pulley.
The magnetic windings upon the pulleys or wheels terminate in insulating rings,
upon which bear springs, brushes or other suitable devices for connecting the
windings with the source of electrical energy.
Instead of having the magnetic windings mounted in circumferential grooves
upon the pulleys or wheels, by one modification of the invention these windings may
be located in grooves passing around the rim of the pulley or wheel and transversely
across its face, or, where the conditions will permit, the two iron pulleys or wheels
may be connected by an iron frame which will carry the magnet winding, one pulley
or wheel forming one pole of the magnet and the other pulley or wheel forming the
other pole of the magnet, the poles being connected by the magnetic helt rope or
chain. The magnetic belt may be made of a number of steel strips placed one over
the other and having upon the outside cross-bars of soft iron secured transversely
to the steel strips by rivets or otherwise, or one or more steel wire ropes may be
employed, or a number of steel wire ropes may be placed parallel and be connected
by crossbars of iron through which the ropes will pass and to which they will be
secured.
Instead of using a belt constructed of magnetic material, one of non magnetic
material may be employed and the magnetic bars may be constructed in the form of
rollers mounted in a frame located at each pulley and bearing upon the belt where
it is in contact with the pulley. These magnetic rollers will be loosely journalled
in the frame and being attracted by the pulley will press the belt upon it, thus
increasing its.adhesion.
Referring to Figures 1 to 7 of the drawing
Figure 1 is a perspective view showing one construction embodying the
invention.
Figure 2.is an elevation of one of the pulleys of Figure 1.
Figure 3 is a sectional view of a portion of the endless belt of Figure 1 with the
iron bars secured thereto.
Figure 4 is a side elevation of a modified form of the apparatus showing the
magnetic bars separate from the endless belt.
Figure 5 is a sectional view of a magnetic wheel with a wire rope serving as an
armature.
Figure 6 is a side elevation showing a modified construction of the wheel driven
by the wire rope.
Figure 7 is a side elevation showing a further modification of the means for
producing magnetism in the pulleys or wheels.
Referring particularly to Figures 1, 2, and 3. A and B are two iron pulleys
mounted upon parallel shafts and connected by an endless belt C. Each of these
pulleys is provided with several circumferential grooves, shown more particularly
in Figure 2, in which are located windings a of insulated wire, connected at the
ends to insulated rings upon which bear contact springs c. These contact springs
being connected with a suitable source of electrical energy indicated by the
circuit 1, 2, each pulley becomes strongly magnetic as indicated by the letters N, S,
in Figure 2, the circumferential ribs or exposed faces of the pulley on opposite
sides of each of the windings being oppositely magnetized. The belt C is preferably
constructed of a number of thin sheet steel strips, placed one over the other as
shown in Figure 3, and upon the outside of these are secured, like the rounds of a
ladder, cross bars d of soft iron which are rivetted to the belt, the strips of steel
being at the same time rivetted together so as to form a continuous belt. The steel
belt and the bars d, bridge the windings of the two pulleys completing the magnetic
circuits around the windings, thus forming armatures or keepers for the magnetic
poles produced upon the pulleys. These magnetic circuits being exceedingly short
and of remarkably low resistance, the attraction of the many keepers to the pulleys
produces a great adhesion of the belt to the pulleys, thus permitting large powers

page_text: to be transmitted through relatively small belts. Experience has shown that with
a four inch pulley and a belt three inches wide, making contact only over one half
of the circumference, the belt will sustain a dead weight of two hundred pounds
without the magnets reaching saturation.
It will thus be seen, here, that by a proper proportioning of the parts a magneto-
mechanical device capable of replacing the toothed wheels in nearly all cases of
power transmission.
In Figure 4 is illustrated a construction in which instead of placing the bars d
directly upon the belt, a frame D is placed on the contact side of one or of cach
pulley, and in this frame are mounted magnetic rollers e having slotted bearings so
as to be capable of a limited movement towards the pulley. The belt passes under
these rollers and, by the attraction of the rollers towards the pulley, the adhesion of
the belt is increased.
In Figure 5 the device is an iron wheel E provided with a grooved face in which
runs a wire rope F. The wheel is slotted circumferentially and provided with a
magnetic winding which strongly magnetizes the wheel giving the opposite sides of
its rim opposite polarities. The wire rope acts as an armature or keeper to the
magnetic poles, forming a magnetic circuit of exceedingly low resistance and
resulting in a powerful adhesion of the rope to the wheel.
Instead of winding the wheel E circumferentially its rim may be provided with
transverse grooves in which windings will be placed, making the projecting surfaces
of the wheels between these windings alternately of opposite polarity as indicated in
Figure 6. The wire rope acts as an armature or keeper for all the magnets thus
formed.
Instead of winding each wheel or pulley in cases where the wheels or pulleys are
sufficiently near to permit of the employment of the construction, the pulleys are
connected by an iron frame G which is provided with the magnet winding h, thus
making one pulley of one polarity, and the other of the other polarity, a magnetic
belt, rope or chain being used to complete the magnetic circuit between the two
pulleys or wheels. This construction does not produce as powerful magnets as in
the constructions already described. It is simply given as an illustration of the fact
that the invention is capable of being carried out in many forms of construction and
is not limited to the special constructions illustrated.
It is obvious that while a belt of magnetic material such as the laminated steel
belt described is desirable, in order to secure the full advantages of the invention,
yet the invention may be used to increase the adhesion of belts of non-magnetic
material, such as leather, rubber-cloth and the like. If the endless belt C of
Figure 1 were a leather or rubber cloth belt, it is evident that the magnetic bars d
would increase the adhesion of the belt to the pulleys, while if the belt of Figure 4
were of non-magnetic material the magnetic rollers & would increase its adhesion.
Referring to Figures 8 to 14 of the drawing,
t:
Figure 8 is a side view of another form of magnetic belting showing both the
belt and the pulleys over which it runs ;
Figure 9 is a top view of a portion of the belt;
Figure 10 is a vertical section of a portion of the belt showing means for securing
.the iron bars to the wire ropes.
Figures 11 and 12 are horizontal sections showing means for securing the ends of
the wire ropes and
Figures 13 and 14 are views of a modified form of the belt and pulleys.
The magnetic belt is composed of a number of steel wire ropes A upon which are
strung cross-bars B of soft iron. The wire ropes pass through holes a in the
bars B, which holes as shown in Figure 10 are preferably tapered from the centre of
the bar outwardly in both directions, and the bar is secured to the wire rope by
"setting" the centre of the bar upon the rope. This is accomplished by providing
cach bar, over the horizontal hole a, through which each rope passes, with one or
more vertical holes or depressions extending from the top surface of the bar down
to near the horizontal hole a, and by inserting a punch in the hole and driving it

page_text: દ
22
downwardly, the metal of the bar will be "set upon the rope, which will be
pinched and held so that the bar is fixed in its position with relation to the rope.
As shown in Figure 9, there may be one hole for each hole a, or two. The bar
being set upon the rope at its centre and the hole a flaring outwardly from that
point in both directions, the flexibility of the belt is assured. The ends of the wire
ropes may be secured, as illustrated in Figure 11, by passing the meeting ends into
a horizontal hole c, which is large enough to receive them side by side and is
somewhat wider at the centre of the hole than at its ends; a screw, bolt or rivet d,
is forced down between the adjoining ends of the rope pressing then outwardly into
the enlarged centre of the hole c, and securely holding the rope ends; or if the rope
is the one at either end of the bar, as shown in Figure 12, the ends may enter the
bar from opposite sides and then he bent at right angles and passed out through a
wider hole e leading out through the end of the bar and provided with an enlarged
centre like the hole c, a screw, bolt or rivet d, being used as before to spread the
ends of the rope out into the enlarged centre of the hole. Various devices for
securing the ends of the ropes may be employed, that illustrated being given only
as one suitable way of doing this. CD are the pulleys over which the endless belt
runs.
These pulleys are of iron and are made strongly magnetic by means of magnet
windings which are placed in one or more circumferential grooves.
Both pulleys
are made strongly magnetic, and the iron bars B of the belt bridge the magnet
windings and close the magnetic circuits about such windings, the bars being
attracted to the face of the pulleys and adhering strongly thereto.
In cases where a considerable reduction or increase in speed is to be attained, for
which purpose the magnetic belting is well adapted to supplant tooth gearing
which heretofore has only been capable of use for that purpose, the surface of
contact upon the smaller pulley D should be made as great as possible.
For this reason the iron bars B are ground to a curve upon their inner faces,
which curve corresponds with the surface of the small pulley, so that the bars
passing over the small pulley are in contact with it throughout their entire surface.
The small pulley D is preferably more strongly magnetized than the larger pulley C
by suitably constructing the magnet windings to accomplish this end, as will be
readily understood. The result of this is to make the belt "strip more readily
from the larger pulley than from the smaller pulley, to which latter the bars will
cling, carrying the belt around over a greater surface of the pulley, as illustrated in
Figure 8, the belt being stripped tangentially from the larger pulley and radially
from the smaller one, or approximately in this relation.
23
In Figures 13 and 14 is shown a modified form of the belt and pulleys adapted
for use where the space laterally is limited, so that a wide face pulley cannot be
conveniently employed. In this form the pulley E is made with a V-shaped face,
provided with the magnet windings, and the soft iron bars B' of the belt are made
V-shaped.
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
1. In the transmission of power, the method of securing or increasing the adhesion
between endless belts, ropes or chains and the pulleys or wheels over which they run
consisting in the employment of electro-magnetism, substantially as set forth.
2. The combination with a pulley or wheel made powerfully magnetic by a
suitable winding, of a belt, rope, or chain running over said pulley, and held thereto
by magnetic attraction substantially as set forth.
3. The combination with a pulley or wheel made powerfully magnetic by a
suitable winding, of a belt, rope or chain running over said pulley, and constructed
partly or wholly of magnetic material substantially as set forth.
4. The combination with a pulley or wheel made powerfully magnetic by a
suitable winding, of a belt constructed of steel or equivalent magnetic material,

page_text: passing over the same said belt being provided with cross-bars of magnetic material
secured thereto, substantially as set forth.
5. A pulley or wheel having one or more circumferential magnet windings and
provided with exposed circumferential surfaces of opposite polarity on the opposite
sides of each of said windings, in combination with a belt rope or chain passing over
said pulley or wheel, and held thereto by magnetic attraction substantially as set
forth.
6. A magnetic belt having in combination one or more wire ropes and transverse
iron bars secured thereto, substantially as set forth.
7. The combination with large and small magnetic pulleys the smaller pulley
being more strongly magnetic than the larger, of a magnetic belt passing over such
pulleys and having transverse iron bars which bear upon such pulleys, such bars
being curved on their inner faces to fit the smaller pulley, substantially as set
forth.
Dated IIS IST
OL
1891.
B. J. B. MILLS.
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.