Note: Descriptions are shown in the official language in which they were submitted.
Vibratory machinery such as screens,
conveyors, shakeouts, and the like conventionally
include a trough-like n~aterial support which is
oscillated in an orbital path to advance material along
the length of the support. The orbital oscillation of
the support conventionally is effected by at least one
motor driven shaft journaled for rotation on a base and
having one or more eccentric sections drivingly coupled
to the material support. In the assembly of an
eccentric shaft of conventional construction with the
vibratory machinery, the shaft is supported on the base
by outboard bearings and the eccentric portion or
portions of the shaft are accommodated in inboard
bearings which are coupled to the material support. To
facilitate assembly oversi~e inboard bearing openinys
have been provided which have had to be fitted with
specially shaped (crescent~ bushing inserts to conform
such bearing openings to the confic~uration of the
associated portions of the shaft~ While carrying no
2~ greater load than the outboard bea~ings~ the inboard
bearings have had to be larger and consequently less
economical to use.
The utilization of bushing inserts ha~ also
not been altogether satisfactory for a number of
reasons. for example, considerable time is involved
and the use of bushing inserts does not always result
in precision alignment of the eccentric shaft with the
several bearin~s, as a consequence of which operation
of the machinery may be adversely affec~ed and
excessive wear of the relatively movable parts
may result, thereby accelerating the necessity of
3l~Z'~ S~
replacement of such parts.
The principal objective of the invention i~ to
provide an eccentric shaft for vibratory machinery o~
the kind referred to and which overcomes the
disadvantages of eccentric shafts heretofore used for
similar purposes. This objective is attained by the
production and use of an eccentric shaft having a
cylindrical, mounting bearing section at each end, a
cylindrieal center section haviny a longitudinal axis
coincident with that of the bearing sections, eccentric
coupling sections outboard of the center section having
coinciden~ longitudinal axes offset from and parallel
to the lon~itudinal axis of the center section, and an
elliptical section joined to each of the coupling
lS sections inboard of the associated mounting bearin~
section. Each elliptical section has a major axis the
length of which is no greater than the diameter of the
largest cylindrical section, and a minor axi~ ha~iny a
length less than that of the major axis. Each
elliptical ~eetion has a first ~,emi~cylindrical surface
formed on an arc having a center on the longitudinal
axis of the center section and a second semi-
eylindrieal surface formecl on an arc havin~ its center
on the longitudinal axis of the eccentric bearing
seetions. Each elliptical seetion is symmetrical about
a longitudinal axis locatecl midway between the
longi~udinal axis of the center section and the
longitudinal axes of the eecentrie eoupling sections.
The construction is such that no bushing inserts are
required in the assembly and disassembly
of the eccentrie shaft with and from ~he remainder of
the vibratory machineryO
t~5~
Figure 1 is an end elevational view of a
vibratory conveyor or the like ec~uipped with an
eccentric shaEt constructed in accordance with the
invention;
Figure 2 is a sectional view, on a reduced
scale, and taken on the line 2-2 o Figure l;
Figure 3 is an elevational view of an
eccentric shaft according to the invention;
Figure 4 ls an end elevational view as viewed
in the direction of the arrows 4-4 of Figure 3;
Figure 5 is a greatly enlarged sectional view
taken on the line 5-5 of Figure 3; and
Figure 6 is a fragmentaryl diagrammatic view
illustrating the manner in which the eccentric shaft is
formed.
A balanced eccentric shaft according to the
invention is adapted for use with vibratory apparatus 1
such as a conveyor, a screen, or the like comprising a
trough~shaped material support member having a bottom 2
and upstanding, spaced apart side walls 3.
Conventionally, the material support is mounted on and
above a base having spaced apart frame members 4 on
each oE which is mounted a bearlng housing 5~ An
eccentric shaft 6, to be described in more detail
subsequently, has its ends journaled în bearings 7
carried by the ~earing housings 5. The shaft has
intermediate portions thereof journaled in bearings 8
carried by bearing supports ~, each support 9 having a
Elange 9a coupled to one end 10 of a drive arm 11
extending longitudinally of the material support and
-- 3
being fitted in the usual manner to a resilient mount
12 fixed at its opposite ends to a pair of brackets 13
suspended from the bottom 2. The bearings 7 and 8 are
conventional, annular bearings of the same size.
The eccentric shaft 6 of the preferred,
illustrated embodiment has a cylindrical center section
14 having a longitudinal axis represented by the dash
line 15 (Figure 3). At each end of the shaft is a
cylindrical bearing section 16, each of which has a
longitudinal axis coincident with the axis 15. The
diameter of each bearing section 16 is uniform and
corresponds to the diameter of the center section 14 so
that no inbalance i5 imparted to the shaft.
Joined to each end of the center section 14 by
a beveled shoulder 17 is an eccentric~ cylindrical
coupling section 18, the diameter of each oE which is
uniform and corresponds to the diameter of the sections
14 and 16. The coupling sections 1~ have coincident
longitudinal axes represented by the dash line 19, the
axes of the coupling sections 18 being offset from and
parallel to the axis 15.
Interposed between each bearing sec~ion 16 and
the a~jacent coupling section 18 is an elliptical
section 20 which will be described more fully
hereinafter. At one end of the shaft 6 is a
cylindrical extension 21 of reduced diameter having a
longitudinal axis coincident with the axis l5~ A
driving pulley (not shown) is adapted to be fixed to
the extension 21 and coupled by a belt or the like to a
driving motor to effect rotation of the shaft 6 about
the axis 15.
~ J
As is best shown in Figure S, each of the
elliptical sections 20 has a semi-cylindrical surface
22 formed on an arc A hav:ing itE; center located on the
axis 19 of the coupling section~ 18. Each elliptical
section has a second semi-cylindrical surface 23 formed
on an arc A' having its center located on the axis 15.
Each of the arcs A and A' is identical in length and
the length of each arc corresponds to the radius oE the
cylindrical sections 14, 16, and 18. As a consequence,
each elliptical section 20 has a major axis M and a
minor axis M', the length of the major axis being no
greater than the diameter of the cylindrical shaft
sections and the length of the minO axis M' being less
than that of the major axis by a distance corresponding
to one-half the spacing between the lon~itudinal axes
15 and 19.
The sha~t 6 may be formed from a cylindrical
~illet 24 fragmentarily and diagrammatically shown in
Figure 6. At each end of the billet is clamped a
~ixture block 25 provided with two lathe center points
26 and 27, the center 26 coinciding with the axis 15
and ~he center 27 coinciding with the axis 19. The
fixtures 25 initially are chucked between the head and
tail stocks of a lathe to support the billet for
rotation about the axis 15. A cutting tool (not shown)
forming part of the lathe removes material from the
billet in a first cutting stage to form the two be~ring
sections 16 ~nd the center section 14. The cutting
tool does not traverse the entire len~th of the billet
24 in the ~irst cutting stage, but skips those portions
thereof at which the coupling sections 18 are to be
formed. In the first cutting st~ge, however, the
surfaces 23 of the elliptical sections are formed.
The partially completed shaft is demounted
from the lathe and remounted between the head and tail
stocks for rotation about the axis 19. The cutting
tool then is set to commence cutting operations at
the inboard end of the bearing section 16 and remove
material from the billet 24 to form the shoulders 17,
the surfaces ~2 oE the elliptical sections 20l and the
remaining half of the cylindrical surfaces of the
coupling sections 18.
The procedural steps in producing the shaft S
can best be understood from Figure 6 which illustrates
approximately one-half the billet and the ~haft. The
billet is cylindrical and has a uniform diameter from
end to end. The radius of the billet lies midway
between the centers 26 and 27.
It will be understood that the following
description relates only to the disclosed portion of
the billet and that the process is continued to the
opposite end o ~he billet.
In the first cutting stage the billet is
rotated about the axis 15. In this stage the cutting
tool traverses the zone X, skips the zone Y, and
traverses the zone X' (which extends to the right hand
end o~ the center section 14). This operation forms
two lonyitudinally spaced cylindrical sections which
will become the ~earing section 16 and the center
section 14. The surface 23 of the elliptical section
20 and one-half the surface of the coupliny section 18
also will be fo~med in this stage.
-- 6
Following mounting of the billet to rotate
about the axis 19 during a second cutting stage, the
cutting tool traver.ses the zone Z (which includes a
portion of the zone Y) and forrns the shoulder 17, the
second half Gf the surfaces of the coupling section 18,
and the surface 22 of the elliptical section 20.
The shaft 6 is completed by forming the
extension 21 and cuttiny it to the desired length.
To assemble the finished shaft 6 with the
remainder of the vibratory apparatus is a simple
matter. The shaft may be first thrust endwise through
the enlarged openings in drive arms 11 until its
central portion 14 is received between them. The inner
race of these inboard roller bearings 8 will have been
premounted on the shaft on portions 18 by slipping them
over the ends 16 of the shaft, and will move through
these enlarged openings which carry the outer race of
the bearings 8. Their mounts 9 can then be slipped
over the ends of the shaft, and slipped over bearings ~
until the ~langes 9a abut arms ll. ~he flanges 9a bolt
to arms ll and finally outboard bearings 7 and bearing
supports 5 can be slipped over the ends 16 of the shaft
and secured in position in frame members 4.
The disclosed embodiment is representative of
a presently preferred form of the invention, but is
intended to be illustrative rather than definitive
thereof. The invention is defined in th& claims.
