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(Jan. 7,1947.
D. FIRTH
.
‘
2,413,817
SHEAVE
Filed Feb. '5, 1945
I
I
INVENTOR.
BYlYQZJLZéJZrZL/W,
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-
2,413,817
Patented Jan. 7, 1947
umrso STATES PATENT ‘OFFICE
2,413,817
SHEAVE
David Firth, South Bend, Ind., assignor to Dodge
Manufacturing Corporation, Mishawaka, Ind.,
a corporation of Indiana
Application February 5, 1943, Serial No. 474,830
5 Claims. ( Cl. 74-23015)
1
Sheaves for multiple V-belt drives should have
accurately formed belt'grooves the side walls of
which should be uniformly wear-resistant. Wear
resulting in. material enlargement of the belt
grooves is objectionable as altering established
pitch diameters. Unequal wear of the belt
grooves would be especially objectionable as in
2
vention gives the advantage of a relatively light
construction of non-metallic material with the
wearing qualities of a metallic sheave. Further
advantages of the invention will be hereinafter
7 indicated.
In the accompanying drawing, there is shown
for illustration a, multiple V-belt sheave of one
practicable construction embodying the inven
terfering with the important objective of main
taining the rubber driving belts equally tensioned
tion.
Fig. 1 is a section of the illustrative sheave
and therefore in engagement with the sheaves at 10 taken on a plane longitudinally of and through
uniform distances from the sheave axes.
the sheave axis.
For conservation of metal, it is desirable to uti
Fig. 2 shows a fragment of the rim portion of
lize wood or other suitable non-metallic material
the sheave partly in section and partly in end
for the construction. of such sheaves. Wood
elevation, this view being a portion of that shown
sheaves of suitable construction can be used un 15
on a reduced scale in Fig. 3.
cler many conditions for duties for whichcast
Fig. 3 on a reduced. scale shows the sheave
iron sheaves of corresponding sizes have been
half in cross section on the line 3-3 of Fig. 1
commonly employed.
The wood sheaves are of
relatively light weight, which is importantly ad
Furthermore, the 20
vantageous in transportation.
wood sheaves can be driven at faster speeds than
the cast iron sheaves without going to pieces by
centrifugal force. However, the wearing quali
ties of wood sheaves are generally interior to those
of cast iron.
'
Sheaves having tractive surfaces of hard wood
transverse of the grain thereof are satisfactorily
wear~resistant under ordinary conditions; how.
and half in end elevation.
Fig. 4 is a diagrammatic representation in
section of an enlarged fragment of the rim por
tion of the sheave.
.
In the drawing, I designates as a whole a lam
inatecl wood sheave body the perimeter of which
25 is formed to provide annular'belt grooves 2 of
V-shaped cross section.
Formed on and cover
ing the perimeter and lining the walls of the belt
grooves is a hard skin-like coating 3 of ferrous
metal or other suitable metallic material, the
coating being bonded to the wood material of the
30
pose the grain of the wood transversely of the
ever the fabrication of wood sheaves so as to dis
tractive surfaces for substantially or nearly the
entire circumference necessitates special shaping
and arrangement of wood pieces, increasing labor
body perimeter by engagement of numerous mi
nute portions of the metallic coating in pores or
interstices of the wood. The coating conforms in
exterior shape substantially to the contour of the
and cost of production. Unless so fabricated, a
wood sheave is liable to wear unevenly, due to 35 body perimeter, and, as best shown in Fig. 4, the
portions of the coating lining the side walls of
presence of soft spots or inequalities of hardness
the belt grooves are ground to provide smooth
in its tractive surfaces. Moreover a wood sheave
surfaces for engagement by the V-belts, these
is liable to wear down rapidly it operated in the
being conical surfaces concentric with and of the
presence of abrasive dust or used under condi
tions such as to be affected by grit between the 40 same slant as the corresponding surfaces provid
ing the side walls of the body grooves.
~
driving belts and walls of the sheave grooves.
The coating may be formed by spraying ‘at
It is therefore desirable to provide‘ a wood
omized or finely divided molten of semi-molten .
sheave with groove walls having hard metal wear
particles of metal on the perimeter of the wood
surfaces. The present invention provides such a
sheave body and on the ?lm of such particles so
sheave of practicable character, readily and eco 45 deposited until there is built up a coating of de
nomically producible in desired‘ forms and sizes.
sired thickness. This involves utilization of a
A sheave embodying the invention ,is charac
method which is in industrial use for the coating
terized by a sheave body of wood or other suit
of metal surfaces to provide corrosion-resistant
able non-metallic material having a metallic skin
and wear~resistant coatings and which has also
like coating formed on, covering and bonded to’ 50' been applied to the coating of glass, paper and
the perimeter thereof and providing circumfer
wood for ornamentation. The method is carried
entially continuous groove wall liners, the exte
out with the use of known apparatus including a
rior of the coating or belt-engaging portions
‘spray gun through the nozzle of which is fed at
thereof being ground or machined and ground to
a constant rate a wire' composed of the metal
provide smooth tractive surfaces. Thus the in 55
2,418,817
3
4
to supply the coating material. Concentric
metallic coatings being easily applicable to any
chambers of the spray gun are connected respec
tively with sources of oXy-acetylene gas, oXy-hy
drogen gas and compressed air. At the nozzle of
forms and sizes thereof.
Another advantage of the invention is that
the metallic coating 3 may be electrically con
the spray gun the wire is melted by an oXy-acetyl
nected with the sheave shaft, for conducting o?
static electricity accumulating on the rubber
one or oXy-hydrogen flame and as it melts is sub
iected to a blast of compressed air, whereby the
driving belts running'in tractive engagement with
molten or melting metal is atomized and sprayed
the sheave, thereby affording protection from
off. As the ?nely divided molten or semi-molten
sparking by static electrical discharges, which is
metal particles strike the wood surface of the 10 of great importance for installations where elec
_ sheave body perimeter, they rapidly chill and
tric sparks would be liable to cause explosions;
solidify, becoming bonded to said perimeter by
thus further increasing the practicability of wood
keying in surface pores or interstices of the wood,
sheaves or enlarging the ?eld in which they can
and bonding and integrating with successively de
be utilized. Electrical connection of the coating
posited particles. There is thus formed a coat
3 with the sheave shaft may be made simply and
ing of substantially uniform or homogeneous na~
inexpensively by a strip of metallic coating ma
ture, composed of integrated and interbonded
terial 4 formed on the face of the wood sheave
metallic grains, which can be easily machined
body and leading from the coating 3 to the shaft.
and ground. The coating is susceptible of taking
In the case of the illustrative sheave, which is of
a very smooth and even glossy ?nish by polishing. 20 the split contractible hub type and has ?tted in
A ground and polished surface of a coating of
its hub bore a split contractible wood bushing 5.
ferrous metal so formed has something of the
the conducting strip ii is continued across the end
aspect of polished granite.
of the bushing as indicated at 6 in Fig. 3, or, more
The coating 3 may be of ferrous or other de
accurately speaking, the conducting strip 4 con~
sired metal or alloy or metallic material com—
tacts with conducting material formed on the
posed mainly of metal but containing carbon, sili
bushing at 6 and contacting with the shaft.
»With respect to its body construction and mode
con or other elements. For example the coating
may be of metal of a cast iron or hard steel com
position or of alloy steel.
rl‘he coating may be of say about the thickness
of heavy paper or thin cardboard or of greater
thickness if desired. Usually a coating of not
more than about one sixty-fourth of an inch
thick is preferable to one of greater thickness, it
being desirable to conserve the use of coating
metal as Well as to avoid undue increase of weight
of the wood sheave.
'
of mounting, the illustrative sheave is in accord—
ance with and embodies the invention disclosed
in the pending patent application of Firth and
Lower, Serial No. 458,829, ?led August 6, 1942,
now Patent No. 2,352,474, dated June 27, 1944.
The sheave body, comprising hub ‘and rim por
’ tions and a connecting Web portion, is built up of
.
' adhesively joined wood plies or laminations ar
ranged transversely of the sheave axis. The web
laminations and corresponding laminations of
the hub and rim portions of the sheave body are
tractive surfaces for the belt groove walls but also
provided by the intermediate discs 1' and outer
a protective armor for the perimeter of the wood 40' discs 8. Additional laminations of the rim por
sheave body, preventing scuffing or chipping
tion of the sheave body, forming overhanging
thereof or breakage of the narrow wood ribs
extension thereof, are provided by the rim rings
formed between the belt grooves, and reinforces
9 ‘and facing rings Eli. Additional hub lamina
and strengthens the wood sheave body.
tions are provided by the complemental halves
Thus the invention substantially increases the
’ ll of hub discs divided by the radial slots 12.
The coating provides not only smooth hard
practicability and e?'iciency of a wood sheave;
obtains the advantage of a relatively light con
struction of non-metallic material with the dura
bility and wearing qualities of a cast iron or hard
metal sheave; renders it unnecessary to fabri
cate wood sheaves with the grain of the wood pre
sented transversely of'the tractive surfaces for
substantially or nearly the entire circumference;
and provides a construction which permits the
use of soft wood, paper board or other relatively
soft, light, cheap materials for the sheave body.
It is contemplated that the bodies of sheaves
embodying the invention may be made variously
from non-metallic materials of the class compris
ing wood, paper and the like, including plywood,
paper board, papienmaché, ?bre board and anal
ogous materials, and also such moldable plastics
.as may be suitable for sheave bodies and sus
The several discs, rings and half discs referred
to may be one piece elements or some or all of
them may be composed of suitable jointed smaller
wood pieces.
Cut through the laminated wood sheave body,
50
at opposite sides of and spaced from the sheave
bore, are a'pair of large openings 13 the inner flat
walls Hi of which are parallel-and perpendicular
to the diametric plane A--B bisecting said open
ings. The portion of the sheave body between
the openings is divided longitudinally of the axis
by the slots [2 extending radially from the hub
bore .to diametrically opposite points beyond the
circumference of the hub. The slots 52, as Well
as the openings I3, extend clear through the
sheave body as shown in Fig. 1. There is thus
provided a contractible split hub unitary with
the surrounding rim portion of the sheave body.
The parts of the hub at opposite sides of the
slots 12 are connected by bolts consisting prefer
ably of slender metal rods it having screw
threaded end portions engaged by the nuts I6
accommodated in the openings 53, flat metal
washers ill being interposed between the bolt nuts
and ?at walls l4- forming the opposite sides of the
sheave hub. By tightening said nuts, the ‘sheave
ceptible of coating of their perimeters by the
method described without injurious effect upon
the peripheral contours of the molded bodies.
The invention is thus conducive to promoting
the utilization of wood and other non-metallic
materials for sheave construction. In this con
nection an important advantage of the invention
is that manufacture thereof is not limited to par
ticular forms and sizes by the use of dies, molds
and the like; the wood or non-metallic bodies be
hub can be contracted on the contractile bush
ing readily producible in desired forms and
ing 5 to clamp the sheave to the bushing and the
sizes, to meet diiiferent requirements as to pitch
diameters and members of belt grooves, and the 75 latter to the shaft, whereby to secure the sheave
2,418,817
6
5
in ?xed relation to and driving connection with
the shaft.
The bushing 5, which may be of metal but is
preferably of wood, is split longitudinally by a
slot l8 extending the full length of the bushing.
In its uncontracted state the bushing ?ts the hub
bore of the sheave and the shaft to which it is ap
plied, though in view of the contractibility of
the bushing the shaft may be of slightly less di
ameter than the bore of the bushing. The sheave
can be used with wood bushings of different inside
diameters to adapt it to shafts of different diam
eters.
.
One practicable method of making a sheave
body of the construction described (which can be
made in several different ways) is as follows.
First there is built up or fabricated in the rough a
laminated wood body or pile of adhesively joined
wood discs, either integral or composite, to pro
vide the laminations for the hub and web and
intermediate portion of the rim or all except the
overhanging extensions of the rim portion of the
sheave body. Having built up such laminated
wood body in any appropriate manner, the next
step is to bore a center hole therethrough to pro
vide the hub bore. Next the openings I3 are cut
through said body. Then said body is split by
sawing through it on the diametric line C—-D,
using a thick saw through the part of the body
which is to form the hub and web, so as to pro
vide the radial slots l2, and using a thin saw
through the surrounding or outer portion of the
laminated body. Said body is thus divided into
two identical half parts. Now the holes for the
hub bolts are drilled in said half parts, and the
bolt rods I5 are inserted in said half parts which
are then glued back together again; or, after in
serting said bolt rods the said two half parts may
I claim:
‘1,
.
'
1. A sheave for power transmission comprising
a peripherally grooved sheave body of wood or
other suitable non-metallic material having a
thin coating of metal covering and adhering di—
rectly to its perimeter and lining the groove‘tyalls
thereof, said coating being composed of inte
grated separately formed grains and bonded to
said walls in driving connection therewith by en
gagement of such grains in surface pores or inter,
stices of said non-metallic material, and the pore,
tions of said coating lining said groove walls‘;
having ground smooth belt-engaging surfaces.
2. A sheave for power transmission comprising
15 a sheave body of wood or other suitable non
metallic material having a plurality of annular
belt grooves formed in its perimeter and a cir
cumferentially continuous and seamless thin me
tallic sheathing conforming to the contour of
and covering said perimeter and lining the walls
of said grooves, said sheathing being a metallic
coating ?tting as a skin and adhering directly
to said perimeter in driving connection therewith
and the portions thereof lining the walls of said
"25 grooves having ground smooth belt-engaging sur
faces.
3. A sheave for power transmission comprising
a sheave body of wood or other suitable non-me
tallic material of laminated formation with its
30 plies or laminations arranged transversely of the
sheave axis and having a plurality of annular belt
grooves formed in its, perimeter, and a circum
ferentially continuous and seamless thin metallic
sheathing conforming to the contour of and cov
2 ering said perimeter and lining the walls of said
grooves, said sheathing being a metallic coating
fitting as a skin and adhering directly to and
binding said perimeter in driving connection
therewith and tying together the plies or lamina
be joined by suitably keying them together.
After these operations there are added wood 40 tions of the rim portion of the sheave, and the
portions of said coating lining said groove walls
rings to provide the laminations for the rim ex
having ground smooth belt-engaging surfaces.
tensions of the sheave body, such added wood
rings being adhesively united to said body and
to one another. The un?nished sheave body
thus made in the rough is now put into a lathe
and shaped to the form desired, as, for example,
that shown in Fig. l.
4. A V-belt sheave for power transmission com
prising a sheave body of wood or other suitable
non-metallic material having one or more annu
lar belt-grooves of V-shaped cross section formed
in its perimeter and having circumferentially
continuous thin metallic ?lms lining the walls of
said grooves and adhering directly thereto in
sheave body of the construction described, the
metallic coating 3, forming a continuous binding 50 driving connection therewith, said ?lms having
smooth belt-engaging surfaces.
around its perimeter, ties together the several
5. A V-belt sheave for power transmission com
laminations of the rim portion of the body and
prising a sheave body of wood or other suitable
effectually reinforces and strengthens the struc
non-metallic material having a plurality of annu
ture.
lar belt grooves of V-shaped cross-section formed
The particular construction of sheave shown
in its perimeter and a circumferentially continu
and described will be understood to be exemplary,
ous and seamless thin metallic sheathing con
the invention being applicable to non-metallic
forming to the contour of and covering said per- ‘
sheaves of various different forms and construc
imeter and lining the walls of said grooves, said
tions and adapted to be mounted by various dif
sheathing being a metallic coating ?tting as a
60
ferent means on the sheave shafts or on sleeves
skin and adhering directly to said perimeter in
to be applied to the shafts.
driving connection therewith, the coating being
In making a sheave embodying the invention,
composed of integrated separately formed grains
the wood sheave body is mounted in a suitable
and bonded to said walls by engagement of such
machine in which it is rotated about its axis, and 65 grains in surface pores or interstices of said non
metallic material, and the portions of said coat
the metallic coating material is sprayed on its
ing lining said groove walls having ground smooth
perimeter while it is so rotated, whereby to ob
belt-engaging surfaces.
tain a coating of substantially uniform thick
DAVID FIRTH.
ness.
‘ It will be apparent that in the case of a
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