A low-friction thin-hub plastic multi-part sheave for handling wire, has two joined disc-like members with conical rim portions which together form a V-groove for the wire. The members have apertured central hub portions provided with facing shoulders that engage cooperable, oppositely-facing shoulders on the outer race member of an anti-friction bearing assemblage, to hold the latter captive between the disc-like members. The central hub portions and anti-friction bearing assemblage have respective, oppositely-facing, parallel exposed side surfaces which are flush and disposed in spaced-apart parallel planes, making for a thin hub assemblage. The cooperable, oppositely-facing shoulders are preferably conical, and the disc-like members have large, shallow circular recesses in their exposed sides whereby cutting-off a rim portion of one member will enable it to nest in the recess of an adjoining, similar but uncut disc-like member so that a plurality of sheaves with cut rim portions can be mounted in tandem on a common shaft and require but little space.

CROSS REFERENCES TO RELATED APPLICATIONS 
1. Copending application of Joseph J. Kovaleski Ser. No. 06/373,325 filed 
Apr. 30, 1982 and entitled RUBBER-LAGGED SHEAVE. 
BACKGROUND 
This invention relates to plastic, multi-part pulleys or sheaves that are 
provided with special, wear-resistant or friction surfaces intended to 
handle wire and like strand material, and more particularly to sheaves of 
this type which can be produced inexpensively and yet are of exceptionally 
high quality. 
In my copending application above referred to I provide an improved sheave 
that is lagged with rubber or rubber-like material and comprises two 
disc-like members disposed broadside to each other and secured together to 
form an annular V-groove for receiving and guiding wire or like material. 
In the V-groove a rubber wear strip is held captive, and the hub portions 
of the disc-like members enclose a ball-bearing assemblage by which a 
low-friction bearing is had on the shaft or spindle. The rubber wear strip 
is cut from a length of extruded strip stock, and the ends are butted, 
forming a joint at one spot on the periphery of the sheave. 
When a number of such sheaves are disposed in tandem on a common shaft and 
in close juxtaposition, the overall axial length of the assemblage can 
sometimes be in excess of the available space that is alloted, due to the 
width of the peripheral V-groove rim portions and also the width of the 
hub portions which mount the anti-friction bearing. It is not possible to 
arrange for a nesting of one sheave with an adjoining sheave to save or 
reduce the space on the spindle, and a certain amount of spacing is always 
necessary to prevent touching or rubbing of the sheaves. 
The cutting of the rubber lagging strip required a careful, somewhat 
precise operation even with the employment of suitable sizing jigs or 
fixtures, and slight variations in the length would show up in the 
finished product and impair the appearance even though performance was not 
adversely affected. 
Other prior sheaves for handling wire and like strands were not, to my 
knowledge, provided with rubber wear strips in the bottom portions of the 
V-grooves and did not have the wear-resistant advantages which come from 
the use of rubber or similar resilient substances arranged to be engaged 
by the strand material. Nor did these prior sheaves l end themselves to 
quick and easy replacement of the lagging substance in many instances, 
particularly where they were located in inaccessible spots. 
The construction of prior sheaves involved tooling and assembly operations 
which brought up the fabricating cost unnecessarily, especially where a 
certain amount of labor was involved. In present-day products, 
labor-intensive components or assemblages are diligently avoided, wherever 
possible. 
SUMMARY 
The disadvantages of prior lagged sheave constructions are obviated by the 
present invention, and one object of the invention is to provide an 
improved low-friction, plastic multi-part rubber-lagged sheave which is 
especially compact and thin, measured axially, whereby a plurality of 
sheaves can be carried on a common shaft in a relatively small space. 
Another object of the invention is to provide an improved, rubber-lagged 
sheave as above set forth, which is particularly inexpensive to produce. 
A further object of the invention is to provide an improved multi-part 
sheave construction in accordance with the foregoing, which enables the 
nesting of adjoining sheaves one in the other by means of a simple 
modification of the rim structure. 
A feature of the invention is the provision of an improved, rubber-lagged 
sheave as above characterized, which has an especially thin hub 
construction, measured axially. 
Another feature of the invention is the provision of an improved sheave of 
the kind outlined, wherein simple and secure means are provided for 
holding the anti-friction bearing assemblage captive in the hub structure. 
Still another object of the invention is to provide an improved 
rubber-lagged sheave as above set forth, wherein the lagging element can 
be endless yet easily and economically fabricated and applied or replaced. 
In accomplishing the above objects the invention provides a low-friction 
thin-hub plastic multi-part sheave for handling wire and like strands, 
comprising a pair of disc-like members having apertured, central hub 
portions and having peripheral rim portions, the latter being adapted to 
form a V-groove in which the wire that is to be handled, is received. The 
central hub portions have opposed facing shoulder surfaces that cooperate 
with shoulder surfaces provided on the outer periphery of the outer 
bearing race member of the anti-friction bearing, apart from side surfaces 
of the race member. Such side surfaces of the race member remain exposed 
and uncovered, and are flush with end faces of the hubs on the members of 
the sheave whereby the thickness of the hub portion of the sheave is 
essentially the same as the axial dimension of the bearing assemblage. In 
consequence, the sheave hub portion is reduced to the absolute minimum in 
thickness, measured axially. 
In addition, each of the disc-like members of the sheave has a large 
circular recess in its outer face, and has a sloped surface on its rim 
portion, which is coextensive with radially outermost surfaces of the 
recesses, to the end that cutting off of a circular part of one rim 
portion of a disc-like member at the sloped surface thereof enables said 
member to be nested in the recess of an adjoining identical but un-cut 
member. This nesting construction enables a plurality of sheaves to be 
mounted in tandem on a common shaft in a manner to require the least 
amount of space, measured axially. Moreover, with such nesting the sheaves 
can have either common rotation one with the other, or else independent 
rotation in which latter case the sheaves will not rub against each other 
to cause unwanted drag or pull. By the use of suitable spacer washers 
between adjoining sheaves, either greater or else lesser spacing can be 
had, according to specific requirements. 
The cooperable shoulders between the anti-fraction bearing assemblage and 
the disc-like members of the sheave are preferably conical in shape, 
although other configurations are possible according to the invention. 
The rubber wear element can be economically molded in the form of an 
endless ring which is removable from the mold by pulling it out of the 
cavity. Due to the resilience of the ring, undercut portions will yield 
during such removal, without difficulty. 
Still other features and advantages will hereinafter appear.

Referring first to FIGS. 1-4, the present improved sheave is seen to be 
constituted of two disc-like members 10, 12 which are secured together by 
means of screws 14 passing through bosses 16 which have their holes in 
alignment. The disc-like members 10, 12 have apertured central hub 
portions 18 and 20 respectively, and have peripheral rim portions 22, 24 
which together form a V-groove 26 in which the wire (not shown) that is to 
be handled, is received. 
In accordance with the present invention, the central hub portions 18 and 
20 are constituted in a unique manner, being provided with shoulder 
surfaces 28, 30 that are opposed, that is, facing towards each other. The 
surfaces 28, 30 are preferably conical, as shown, and are thus directed 
almost radially inward or toward the axis of the sheave. These surfaces 
have axial components insofar as the forces on them are concerned, due to 
their angularity with respect to the axis 32 as can be seen in FIG. 2. 
Held captive by the hub portions 18, 20 of the disc-like members 10, 12 is 
an anti-friction bearing assemblage designated generally by the numeral 
34. The bearing assemblage 34 has an inner race member 36 and an outer 
race member 38 which engage ball bearings of usual construction. According 
to the invention the outer race member 38 is provided on its outer 
periphery with oppositely-acting annular shoulder surfaces 40, 42 which 
are cooperable with the shoulder surfaces 28, 30 of the hub portions 18, 
20 of the disc-like members 10, 12 for the purpose of accurately 
positioning the bearing assemblage 34 and securely holding it captive. 
This unique construction enables the end surfaces of the hub portions and 
end surfaces of the bearing race members to be flush with each other, 
making for a thin hub structure of the sheave which saves space axially. 
Referring to FIGS. 1 and 2 it will be seen that the end face 44 of the hub 
20 and the end face 46 of the outer bearing race member 38 are flush, as 
are also the end faces 48 and 50 of the hub 18 and race member 38. As is 
usual, the end faces of the bearing assemblage 34 are also flush with each 
other, these being the face 46 of the outer race member 38 and the face 52 
of the inner race member 36 as visible in FIG. 1. The opposite faces 50 
and 54 of the bearing race members are flush also, as shown in FIG. 2. All 
such end faces are seen to lie in two, spaced-apart radial planes that are 
normal to the axis 32 of the sheave. 
The disc-like members 10 and 12 of the sheave can be identical with each 
other, as shown, whereby but a single mold will be required to form them 
of plastic material. 
Further, in accordance with the present invention, the members 10 and 12 
are provided with large circular recesses 56 and 58 in their outer 
surfaces for a purpose now to be described. The rim portions 22 and 24 of 
the disc-like members have sloped surfaces 60 and 62 which are coextensive 
with the radially outermost surfaces of the recesses 56 and 58 
respectively whereby a cutting off of a circular part of one rim portion 
(22 or 24) at the cylindrical wall of the large circular recess will 
result in part of the sloped surface (either 60 or 62) associated 
therewith, to remain, thereby enabling a plurality of sheaves to be 
mounted in tandem on a common spindle. Such tanden arrangement is 
illustrated in FIG. 6, wherein two sheaves 64 and 66 have parts of the 
rims of members 68 and 70 thereof cut off, enabling these sheaves and more 
specifically, the members 68 and 70 to nest in recesses 72 and 74 of 
sheaves 76 and 64 respectively. By such nesting arrangement a number of 
sheaves can be mounted on a common shaft in tandem and require relatively 
little room, measured axially, and this is an important feature of the 
present invention. Contributing to this compact construction is the thin 
nature of the hub portions of the sheaves, as will now be understood. 
In FIG. 6, spacer washers 78 and 80 are shown, engaged with the disc-like 
members to maintain the desired spacing between the respective sheaves. It 
is considered that the sheaves 64, 66 and 76 are intended to rotate 
simultaneously in the same directions and at the same speed, in FIG. 6. 
However, the sheaves can rotate independently by utilizing smaller spacer 
washers, such as the washers 82 and 84 shown in FIG. 2, which engage the 
inner race member 36 of the bearing assemblage 34 instead of the disc-like 
members. Or, somewhat larger washers such as the washer 86 illustrated in 
FIG. 7 can be employed, for engagement with the bearing and the hub 
portions of the disc-like members where independent turning of the sheaves 
is not required. 
As provided by the invention, a wear-resistant endless ring 88 of rubber or 
rubber-like material is held captive in the V-groove 26 of the sheave. The 
ring has an outer, annular groove 90 and a cylindrical inner surface 92, 
and is held captive in two circular grooves 94 and 96 of the disc-like 
members of the sheave. Due to the resilient nature of the ring 88 it can 
be readily molded in a simple cavity having undercuts and stripped 
therefrom after the molding, since the walls of the groove 90 will readily 
yield to permit such removal. Replacement of the wear ring 88 can be 
easily accomplished by removing the four screws 14 to enable separation of 
the disc-like members 10 and 12, as can be understood. 
In the assembly of the sheave, the screws 14 distort the disc-like members 
as the screws are pulled up tight, this being shown in FIG. 2. Such 
distortion places the members under continual stress, and insures that the 
bearing assemblage 34 will be at all times securely retained in proper 
position in the hub portion of the sheave. Also, in consequence, the wear 
ring 88 will at all times be securely held captive in the rim portion of 
the sheave. 
It will now be seen from the foregoing that I have provided an improved 
low-friction thin-hub plastic multi-part sheave for handling wire and 
similar strand materials, which has a number of advantages. A plurality of 
such sheaves can be nested on a common spindle in a manner to occupy a 
minimum of space axially, by merely cutting off rim portions from each 
sheave to be nested. The resultant V-grooves of the nested sheaves are in 
part made up of two rim portions, one from each of adjoining sheaves. The 
sheaves have especially thin hub portions, and yet securely retain 
anti-friction bearing assemblages in proper alignment. Simple spacer means 
can be employed, by which the sheaves when tandem-mounted will not rub 
against each other but instead are freely moveable, independently of each 
other. The structures involved are especially simple and inexpensive to 
fabricate and assemble, making for low-cost manufacture. 
Variations and modifications are possible without departing from the spirit 
of the claims.