Improvements in Means for Inoreasing the Adhesion of Belts and Pulleys.
Year: 1896

page_text: Date of Application, 1st Sept., 1896-Accepted, 10th Oct., 1896
COMPLETE SPECIFICATION.
Improvements in Means for Inoreasing the Adhesion of Belts and
Pulleys.
I, EDWARD NELSON WALLIS, of 25 North Juniper Street in the City of
Philadelphia, State of Pennsylvania, United States of America Mechanical
Engineer do hereby declare the nature of this invention and in what mauner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
The object of my invention is to cause a driving belt to adhere more firmly
than usual to the surface of the driving or driven pulley with which it is in contact.
This object I attain by withdrawing the air from the inner side of the belt, either
before or after the latter comes into contact with the periphery of the pulley.
I will describe any invention with reference to the accompanying drawings.
Figure 1 of which is a longitudinal section of a belt pulley provided with meaus
in accordauce with my invention for increasing the adhesion of the belt ;
Figure 2 is a transverse section partly in elevation ;
Figure 3 is a side view of the pulley ;
Figure 4 is a longitudinal section illustrating a modified form of pulley
embodying my invention;
Figures 5, 6 and 7 are longitudinal sections of another form of pulley illustrating
still further modifications of the invention.
Figure 8, is a transverse section on the line 8-8, Figure 7; and
Figures 9, 10 and 11, are views ou a reduced scale illustrating other means of
carrying out my invention.
Que primary cause of the slipping of belts on pulleys is the formation of a
cushion between the belt and pulley by air carried forward by the inner side of the
rapidly moving belt and trapped between the belt and the periphery of the pulley.
lu carrying out my invention, therefore, I use means for withdrawing this air and
thus preventing the formation of the objectiouable cushion between the pulley and
the belt.
In the pulley shown in Figures 1, 2 and 3 A represents the periphery or rim
and B the spokes of the pulley the latter being hollow and open at their outer cuds
Bo as to form cylinders for the reception of a series of plungers or pistons D. These
plungers or pistons fit in the hollow spokes with comparative snugness but so that
they can be moved to and fro therein without much friction, each of the hollow
spokes and its contained plunger or piston thus constitutes a pump whereby on the
inward movement of the piston air may be drawn into the hollow spoke from the
outer end of the same or on the outward movement of the piston, air may be
expelled from the spoke.
Each of the spokes B has in one side a slot a through which a lug or projection
on the piston or plunger contained within the said hollow spoke passes. This lug
hus at the outer end an antifriction roller b which is engaged by a cam F mounted
upon a hanger for the shaft G or upon some other available fixed support. As the
pulley rotates, the pistons or plungers in the hollow spokes will bo caused by the
cam and rollers 6 to reciprocate in the said spokes the cam F being so formed
that the said pistons will be drawn inward during that half of the rotation of the
pulloy when the belt is in contact with the periphery or rim thereof and will be
pushed outward during that half of the rotation of the pulley when the belt is
free from contact with the said rim as will be clearly understood by reference to
the drawings. By this means a partial vacuum is created in each spoke during the

page_text: time that the outer end of the same is closed by the belt, hence the maintenance
of an air cushion between the belt and pulley is effectually prevented and the belt
is drawn down firmly into contact with the periphery of the pulley.
In order to increase the area of the belt which is under the influence of the
partial vacuum created in the hollow spokes of the pulley, grooves or channels d
with wings or branches d' extending therefrom may be formed in the periphery of
the pulley, as shown in Figure 3, each of these grooves or channels communicating
with one of the hollow spokes B.
While I prefer to utilize the spokes of the wheel to form pump cylinders in the
mauner described it will be evident that these cylinders may be independent of the
spokes if desired.
In Figure 4 I have illustrated a construction of pulley or wheel in which the
pump cylinders are independent of the spokes and also a modified arrangement for
operating the pistons or plungers in the said pump cylinders. In this case the
pump cylinders are in the form of short tubes B' projecting inwardly from the rim
or periphery of the pulley and have short plungera D' which are connected by
links to arms g hung to suitable bearings on the spokes or on the rim or periphery
of the pulley and connected at their outer ends by means of links g' to hinged
plates forming sections of the rim or periphery of the pulley.
When the pulley is rotated in the direction of the arrow, Figure 4 these hinged
plates or sections follow the pump cylinders B' and such of the said hinged sections
ne are free from the restraining influence of the driving belt will be thrown
outward by centrifugal force so that the plungers counocted thereto will be moved
outwards in their respective cylinders.
If desired centrifugal action may be aided by the resilience of the arms g in
order to project the hinged sections outward when they are free from tho
restraining influence of the belt, the arms 9 in such case being rigidly connected to
the pulley.
As 2000 as one of the hinged sections comes into contact with the driving belt it
is depressed thereby so as to be flush with the general surface of the periphery of
the pulley and hence causes an inward movement of the plunger in the pump
cylinder in advance of the game, so as to create in the said cylinder the desired
partial vacuum for drawing the belt into firmer contact with the periphery of the
pulley.
As soon as each pump cylinder reaches a position where its outer end begins to
be uncovered by the belt the partial vacuuin in the said cylinder is destroyed, and
hence the belt can freely leave the pulley rim, the further forward movement of
the pulley freeing the hinged section and permitting of the projection of the
plunger in the cylinder preparatory to another inward movement of the same when
the hinged section again strikes the belt.
My invention can also be carried out without the employment of cylinders and
pistons as a means of creating a partial vacuum, a rotary fan or exhaust device
being applicable for this purpose in many cases, thus in Figuro 5 I have shown a
torin of belt pulley which is closed at one end but open at the other end, aud in the
open end is arranged an exhaust fan H of ordinary construction, the hub of this
fan being secured to a projecting portion G of the pulley shaft G'. When the
pulley is rotated the exhaust fan H is likewise rotated and causes a partial vacuum
in the interior of the pulley so as to cause an inflow of air through perforations or
slots i formed in the rim of the pulley. These slots are so proportioned that those
which are uncovered by the belt will not be sufficient in aron to supply the volume
of air required by the draft of tho lan, hence there will always be maintained in
the interior of the pulley a partial vacuum which will exert its influence through
those slots which are covered by the belt, to draw the said belt more firmly than
usual into contact with the pulley.
In order to restrict the flow of air through the openings i which are not covered
by the belt, in some cases use a segmental shield or check plate HI' suitably
supported in proximity to the inner side of that part of the pulley which is not

page_text: covered by the belt. As shewn in Figure 5 this check plate is mounted upon a
fixed bracket H. Figure 6 shows a modified form of pulley in which the fan H
instead of being carried by an extension of the pulley shaft, is mounted upon an
independent shaft H so that it may if desired be driven in a direction the reverse
of the direction of rotation of the pulley. In Figures 7 and 8 I have illustrated a
modification in which in place of the rotating exhaust fan I employ a fixed sleeve I
mounted upon a fixed arm or bracket so as to be supported in a position con-
centric with the axis of rotation of the pulley, this sleeve having outwardly flaring
and spirally curved blades or vanes ni which extend outwardly to points close to
the inner end of the rim of the pulley as shown in Figure 8. As the pulley is :
rotated in the direction of the arrow the air within the sand pulley partakes of this
rotating movement and is thus brought into contact with the blades or vanes m
whereby it is thrown outward and discharged through the open end of the pulley
thereby creating a partial vacuum therein. In the periphery of the pulley' A'
sloten are provided which perform the same function as the slots of the pulley A
shown in Figure 5. In this case the shield or check plate which is represented
at 1, is mounted directly upon the vanes m, and while this construction is preferred,
the check plate I' could be supported as shown in Figures 5 and 6 upon a suitable
bracket, independent of the vanes, which latter could he mounted on a separate
sleeve encircling the pulley shaft so as to be capable of being revolved in a direction
opposite to that of the pulley.
lu all of the constructions thus far described, the operation of the air exhausting
devices is dependent upon the rotation of the pulley, but the exhausting of the
air may be effected by meaus independent of the pulley itself for instance in
Figure 91 have shown a construction of pulley similar to that of. Figure 5, but
baving its outer end closed by a plate the outer edge of which does not however
come into actual contact with the inner surface of the pulley rim. This plate has
n central pipe which may be in communication with any convenient exhausting
apparatus, so as to continually maintain a partial vacuum in the pulley when the
latter is in operation. Neither is it absolutely necessary to my invention that the
air shall be withdrawn from between the belt and the pulley, as it may be with-
drawn from the inner face of the belt just before the latter reaches the rim of the
pulley, by an exhaust pipe such as shown at Figure 10, or the air may be
withdrawn by other means than exhaust mechanism, a brush w such as shown in
Figure 11 rotating in contact with or in close proximity to the inner face of the
belt, and in a direction the reverse of the direction of movement of the latter
beiug in some cases available for preventing the cushioning action between the belt
aid pulley.
Having now particularly described and ascertained the nature of my said inveu-
tion and in what manner the same is to be performed declare that what I
claim is :-
1. The combination of a belt and pulley with means for positively withdrawing
air from the inner face of the belt, and thereby preventing the formation of an
air cushion between the belt and pulley substantially as and for the purpose
hercinbefore described.
2. The combination of a belt and pulley with air exhausting mechanism for
withdrawing air from the inner face of the belt substantially as and for the purpose
hereinbefore described.
3. The combination of a belt and a belt pulley having openings in the rim or
periphery with means for exhausting or partially exhausting the air from the
said openings when they are covered by the belt substantially as hereinbefore
described.
4. The combination of a belt and a belt pulley having openings in the periphery
or rim, with air exhausting devices communicating with the said openings and
depending for their operation upon the rotation of the pulley substantially as
hereinbefore described.

page_text: 5. The combination of a belt and a belt pulley having openings in the periphery
or rim, with inclined vanes for withdrawing air from the interior of the pulley as
the latter is rotated substantially as hereinbeforo described.
6. The combination of a belt and a belt pulley having openings in the periphery
or riu, inclined vaues for withdrawing air from the interior of the pulloy as tho
latter is rotated, and a guard or check plate adapted to cover those openings
in the pulley which are not covered by the belt substantially as hereinbefore
described.
7. The combination of a belt pulley having openings in the periphery or rim
and stationary inclined vanes mounted on the inside of the pulley and serving to
discharge air therefrom as the pulley is rotated substantially as hereinbefore
described.
8. The combination of a belt pulley having openings in the periphery or rim
and fixed inclined vaues arranged in the interior of the pulley and serving to
discharge air therefrom as the pulley is rotated, and a guard or check plate
carried by the said vanes and serving to cover the openings in the pulley which
are not covered by the belt substantially as hereinbefore described.
9. The combination of a belt pulley. having openings in the periphery or rim,
and a rotating fan adapted to withdraw air from the interior of the pulley aud
thus cause an inflow of air through the openings in the periphery or rim substan-
tially as herein before described.
10. A belt pulley having in the periphery or rim openings communicating with
pump cylinders, pistons in the suid cylinders and means for effecting the
reciprocation of the said pistons as the pulley rotates substantially as herein-
before described.
11. A belt pulley having openings in the periphery or rim, pump cylinders
communicating with the said openings, pistons in the said cylinders, and a fixed
cam, whereby, as the pulley rotates the said pistons are caused to reciprocate in.
the cylinders substantially as hereinbefore described.
12. A pulley having openings in the periphery or rim, hollow spokes
communicating with the said openings and constituting pump cylinders, pistons
contained in the said hollow spokes, and a fixed cam, whereby on the rotation of
the pulley the said pistons are caused to reciprocate in the hollow spokes substan-
tially as hereinbeloro described.
13. The combination of a belt pulley having openings extending through the
periphery or rim and communicating with channels or passages formed in the
outer surface of the said periphery or rim with incans for exhausting the air fron
the said openings, and the channels communicating therewith, when the said
openings and channels are covered by the belt substantially as hereinbefore
described.
Dated this 1st day of September 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inu Fields, London, W.C., Agente.