Note: Descriptions are shown in the official language in which they were submitted.
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App~ratu~ ~or Processing
Particulates ~nd the Like
Description
Technical Field
The pres2nt lnvention relates generally to vibra-
tory apparatus, and more particularly to an apparatus for
processing particulates or the like.
Backqround Art
Often, it i~ desirable to compact loose particu-
lat~s to remove air voids therefrom. One example is in a
metal casting proces~ in which foundry ~and is compacted
about a pattern to create a mold. In ~ome ca~es, the pat-
tern may bs of such complex shape that special techniques
must be used to ensure that all air voids are removed from
the particulate matter and all passages and cavities in the
pattern are filled. One prior method of compacting particu-
lates about a complex pattern i~ disclosed in applicant's
prior U.S. Patent No. 4,456,90fi, assign~d to the assignee of
the instant application.
The above-noted patent di~closes a vibratory meth-
od which utilizes an apparatus having vibration generators
comprising horizontally ~ounted motors having eccentric
weights thereon. The generators are vperated to vi~rate a
bed which in turn ~upports a flask containing the pattern
and foundry sand. Initially, the generators are operated to
produce a vibrato~y acceleration on the- mold flask and its
contents in exces6 o~ the acceleration due to gravity. This
acceleration cau6es the sand to ~luidize and thus flow into
and completely ~ill cavities in the pattern. After a short
period of vibration at accelerations in excess of gravity,
- the ~troke o~ the motors i5 reduced to reduce the accelera-
tion ~o a ~a~nitude less than the acceleration of gravity.
This in turn compacts the f~undry ~and in place allowing it
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to r~tain its position when ~olten ~etal ~ sub6equently
intrcduced intG th mold fl~ko
Summ~r~ ~f the Invention
In accordance with the present invention, an appa-
ratus for processing particulates including fluidizing and/or
compacting 6ame accompli6hes such ~bjectives in a ~imple and
effective fashion.
The apparatus includes a vibratory bed, a base, a
suspension coupled between the vibratory bed and the base
whereby vibration of the vibratory bed is isolated from the
base and a vessel carried by the vibratory bed for holding
the particulates wherein vibrational motion of the vibratory
bed in turn causes the vessel to vibrate and thereby fluidi2e
and/or compact the particulates. The vibratory bed includes
a motor having a vertically disposed shaft, at least one
eccentric weight di6posed on the shaft, a housing secured to
and enclosing the motor and a bed plate disposed atop the
housing wherein operation of the motor impart~ vibrational
motion to the bed plate. Advantageously, this motion is
vibrogyratory in nature along an axis which, if upwardly
projected, would describe the ~urface of an inverted cone.
In the preferred emb~diment, the ~otor ~haft in-
cludes first and second ends which extend outwardly from the
motor and fir6t and second eccentric weights adjustably
mounted radially outwardly from the ~haft 60 that the ampli-
tude of the vibrations imparted to the vibratory bed can be
varied. Unlike prior dev~ces, it has been discovered that
during operation of the instant invention at a constant mo-
tor speed, the vertical components of the vibrations at
various contact points when the apparatus is operating with
the acceleration ~n excess of gravity causes multiple
-~ impacts ~or each revolution of the 6haft at fre~uencies
which are ~ultiples of a fundamental freguency~ This
multi-freguency vibration qulckly and effectively ~luidi~es
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the particulates so that all of the cavities in the pattern are
filled without damage to the pattern.
In one form of the invention there are at least three
contact points between the vessel and the bed plate whereupon
operating the apparatus with an acceleration in excess of
gravity will create a number of multiples of the fundamental
frequency equal to the number of contact points. Increasing
the number of contact points increase~s the ratio of impact
frequency to shaft revolutions per minute.
Also provided are means for maintaining substantial
relative alignment of the vessel and the bed plate so that
rotation of vessel relative to the bed plate is prevented.
The invention in another aspect comprehends apparatus
for processing particulates, including a vibratory bed
including a horizontally disposed bed plate, a support carried
by the bed plate, a vertically disposed shaft carried by the
support and at least two eccentric weights vertically spaced
apart on the shaft, the weights being radially adjustable
relative to the shaft and circumferentially adjustable relative
to each other, wherein rotation of the shaft imparts
vibrational gyratory motion to the bed plate. A vessel for the
particulates is carried atop the bed plate and means between
the vessel and the bed plate is provided for permitting
unrestrained vertical motion between the vessel and the bed
plate and for limiting relative horizontal motion between the
vessel and the bed plate, wherein the vessel is movable
relative to the bed plate such that vibrational gyratory motion
of the bed plate impacts the vessel to cause the vessel to
vibrate at multiple frequencies for fluidizing or compacting
the particulates in the vessel.
Still further the invention comprehends apparatus~for
processing particulates wherein there is a vibratory bed plate,
a motor suspended from the bed plate having a vertically
disposed shaft with spaced end portions and vibration
generating means mounted on each end portion of the shaft for
imparting vibrational gyratory motion to the bed plate. A
vessel has means for loosely supporting the vessel on the bed
plate which means comprises plural contact means between the
bed plate and the vessel for restraining the vessel movement in
the horizontal direction to be the same as the horizontal
movement of the bed plate and for permitting the vertical
component of the vibrational gyratory motion when in excess of
gravity to lift the vessel from the bed plate progressively
from one contact means to the next. Thus the vibrational
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gyratory motion of the bed plate will impact the vessel with
multiple impacts and various frequencies with each revolution
of the shaft so as to fluidize or compact the particulates in
the vessel.
Brief Description of the Drawin~s
Fig. 1 is a plan view, partially in phantom, of the
compaction apparatus of the present invention;
Fig. 2 i6 an elevational view of the apparatus shown
in Fig. 1 with portions broken away to reveal the structure
thereof and with dashed lines added to illustrate the vibration
of the apparatus when in use'
Fig. 3 is an exploded perspective view of the
apparatus shown in Figs. 1 and 2 with portions broken away to
reveal the construction thereof;
Fig. 4 is an enlarged fragmentary elevational view of
a portion of the apparatus shown in the preceding figures with
dashed lines added to illustrate the vibration of the apparatus
in use;
Fig. 5 is a partial elevational view of a modifed
form of the invention with the vessel supported on at least
three points and a pattern in the vessel.
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Description o~ e P~ferred E~bodiment
}~e~erring now to the figuroE~, there 1B illustrated
therein an ~pparatu~ 10 for proces6inS~ particulates 12, such
aE; fluidizing and compacting foundry 6and or the like. It
~hould be noted that th~ apparatus lû may be u6ed to fluidize
and~or compact other particulates, if desired.
The apparatu~ 10 includ~ a 'ba~e 14 ~shown $n com-
plete form in Fig . 3 ) whlch oo~prise~ ~ tripod ~n~luding
three legs 16a, 16bl 16c ~oined by cro6~-bars l~a, 18b, 18c.
(Only the cross-bar~ 18b, 18c are v~ le in F~g. 3 . )
A motor 20 include~ a motor shaft 22 having first
and eecond ends 24a, 24b which extend outwardly in a vertical
direction from the motor 20. At least one and preferably
two eccentric welght~ 26a, 26b are dispc~sed on the first and
second ends 24a,24b o~ the shaft 22. ~he ecoentric ~eights
26a, 2Sb include an arm 27a, 27b releasably secured to the
shaft 24. Weight blocks 28 are ~dju~tably ~ecured to the
arms 27a,27b to increas~ or decrea~e the vibratory forces
created by the rotatlon OI the eccentri~ weights. Appropri-
ate other well known ~eans can be u~ed ~o provide the e~cen-
tric weights on the 6haft and to vary the relative positions
of the weight6 with rèspect to the axi~ of the shaft and to
each other. See my earlier U.~. ~atents 3, 358, 815 and
4,168,7i4. The motor 20 could be a var~abla speed mo~o~
with appropriate w~ll kno~n ~eans ~or varying the motor
speed as desired.
A hous$ng 32 ls ~ec:ured to and ~ncloses the mntor
20. A plurality o~ threaded 6tud6 34 exkend through th~
housing 32 and are maintained in position by means o~ nuts
3 6 . The threaded ~tuds conta~t the motor casing and re-
strain $t against movament within the hou ing 32. Any well
known apparatu~ ~or ~ecuring the motor ~ to the hous$ng 32
is contemplated.
Di~;posed atop the housing 32 i~ ~ horizontally
disposed bed plate 40 having a main portion 42 and an o~fset
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~lange portion 44 wh~ch de~ln~s ~ ~t~pped channel or recess
46. The bed pl~t3 40 i~ ~oined to thQ hou~ing 32 by any
suitablP mean~, ~uch aæ by the weld 48 ~hown in Fig. 4.
The motor 20, ~he ecoentric weight~ 26, the hous-
lng 32 and the bed pl~te 40 together compri~s ~ vibratory
bed where~n operation o~ the motvr 20 imp~rt~ vibrat~onal
motion t~ the housing and to the hor~-zontally di~posed bed
plate 40. A ~uspenæion 50, pr~:E~ra~ly in the ~orm o~ coiled
springs 52a,52b,52c is disposed b~tw~en the. bed plate 40 and
the ba~e 14. The springe 52a,52b,52c could b~ resllient
blocks or the llke. The ~u~penl3ion 50 i~olate~ the vibration
of the vibratory bed, and more particularl~ the bed plate
40, from the base 14.
A cushion 56 in the form of an ~lastomeric body
may be disposed within the recess 46 of the bed plate 40.
In the illustrated form, a vessel 60 ~it~ atop the cushion
56. The vessel 60 has a hollow interior 62 for holding the
particulate material 12 and, in the case of a ~oundry opera~
tion, a pattern 61. ~he vessel 60 may be a conventional
mold flask that i~ circular or sguare in cross-section,
although it ~ay have a different cross-~ectional ~hape.
The vesQel 60 in¢ludes an outer ~lange 64 which,
when the vessel 60 i8 6eated on the cushion 56, i~ vertically
spaced above and i~ substantially parallel to the bed plate
40. At lea6t ona and preferably three alignment pins
66a,66b,66c exten~ through aperturea in the ~lange 64 and
project into at lea6t one and pre~er~bly three po5itionlng
- cups 68a,68b,68c 6ecursd to an upper ~aae 70 of main portion
42 of the bed plate 40. The plns 66 have a diameter less
than the inner diameter of the cups 68 60 that a limited
amount of lateral movement o~ thP vessel 60 relative to the
bed plate i8 permitted. Thl6 relative ~ovement i5 somewhat
dampened by the elastomeric cushion 56.~ This limited
lateral relative movement b~tween the ve~el 60 and the bed
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plate 40 i6 ~hown by the dashed line~ of Fig. 4 and is
sufficiently s~all to prevent 6ubstantial rotation o~ the
vessel 60 ~bout it~ center axi~ relative to the bed plate
40. The alignment pins 66 and the cups 6~, therefore, co~-
pri6e means for maintaining ~ubstantial relative alignment
of the vessel and bed plate.
In operation, as the motor 20 rotate~, the eccen-
tric weights 26a,26b impart vibrational energy to the bed
plate 40 through the housing 32. The bed plate 40 vibrates
in a vibrogyratory fashion wherein the axis 80 (Fig. 2) of
the bed plate through the center thereof and perpendicular
to the surface 70 i8 inclined from the vertical and defines
substantially a conical surface as it vibrates. This vibra-
tory motion is transmitted through the elastomeric cushion
56 to produce a gyratory vibrational motion of the vessel
60, as shown by the da6hed lines in Fig. 2. During such
operation, the base 14 remains substantially ~tationary ow-
ing to the isolation provided by the suspension 50.
The operation is carried out in two phases, fluid-
ization and compaction. In phase one, the 6and is fluidized
by virtue of operating the ~ibration generator to produce
accelerations in excess of gravity. Acting like a fluid,
the sand fill~ all passages and cavities of a pattern sus-
pended in the vessel 60. It has ~een found that as the
acceleration approaches lG the sand i~ being fluidized and/or
compacted.
The amplitude o~ the vibrations is then reduced,
by reducing rotational ~peed of the eccentric weights or by
reducing the effective mass of the eccentric weights by us-
ing the system shown in U.S. Patent No. 3,358,815 or in U.S.
Patent No. 4,168,774. Reducing the amplitude of vibrations
60 that the acceleration i~ less than gravity compacts the
-~ sand.
The vibrational gyratory motion o~ the bed plate
causes the bed plate ~o impact the vessel at multiple
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frequencies. That i8, the vertical component6 of the vibra-
tion6 ~t variou6 contact point6, when the vibr~tional forces
are in exce~6 ~f the acceleration of gravity, produces ~ultip_-
impacts between the bed plate ~nd the vessel for ~ach revolu-
S tion of the ~haft.
Luring the ~luidizatisn process, the motor devel-
ops sufficient vibrational forces in th~ bed plate 40 to
create accelerations in excess of gravity. Portions of a
bottom lip 90 (Figs. 3 and 4) of t:he vessel 60 thereby vibro-
1U gyrationally move out of contact and into contact with the
cushion 56 (if u6ed) or a top ~urface 92 of the flange por-
tion 44 (if the cushion 56 is not u~ed). This action pro-
duces multiple impacts of the vessel 60 against the bed plate
40 so that the vessel 60 vibrates at various frequencies,
even when the motor ~peed i8 constant. ~hese frequencies
have been found to consist of a fundamental frequency and
integer multiples thereof wherein the fundamental frequency
is the same a~ the rotational 6peed of the motor 20. This
multi-frequency vibration readily fluidizes the particulates
and minimizes the incidence of damage to a pattern in the
vessel.
As an example, with the shaft rotating at 2140
RPM, the vibrational gyratory motion of the bed platP will
impact the vsssel with multiple impact6 and at various
2~ frequencies with each revolution of the ~haft. The various
frequencies will be integer multiples of a fundamental
frequency which i~ the æame as the rotational speed of the
motor. The number of impacts will be egual to or greater
than the cpeed of the motor.
Applicant ha6 conducted several test6 of an appa-
ratus ¢onstructed according to the foregoing details, each
at a different motor speed, and has achieved the following
results.
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ABLæ 1 - ~ot~r Speed 2140 ~PM
Amplitude ~f
Measured Vibration
Vibrational Mea~ured at a Calculated Integer
5Freguencies P~rticular Point Acceleration ~ultiples
(strskes per on the Flange 64 of Vessel of Motor
minute) ~inchesL_ 60 ~'s~ _ Speed
2140 0.022 1.43
4280 0.003 0.78 2
108560 0.~013 1.35 4
12800 0.0005 1.16 6
TABLE 2 - Motor SPeed 3000 RPM
3000 0.015 1.92
6000 0.001 0.51~ 2
1512000 0.0007 1.43 4
18000 0.00025 1.15 6
TABLE 3 - Motor SPeed 2500 RPM
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2500 0.0023 0.204
5000 0.0019 0.675 2
2u 12600 0.00026 0.586 5
17600 0.0002 0.88 7
22400 0.00017 1.21 9
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F~g. 5 ~hows a modi~ied form of the invention
wherein all of the parts that are the 6ame as ~n Fig. 3 are
ident~fied wi~h the sa~e numeral~. Ihe vessel 60 contain-
ing, for instance, sand 12 and a pattern 61 ha6 three equally
spaced apart protrusione, contact pads or cont~ct points 63
extending downwardly grom the lower edge 90 (only 2 of the
protrusions ox pad6 63 are visible in Fig. 5~. The pads 63
contact either the ring 56, when a ring i6 used, or the
flange surface 44 when no ring i5 used. The three contact
1~ pads or points 63 locate the impact surfaces between the bed
plate 40 and the vessel so that the impact freguencies cause~
by the ~ultiple impacts between the bed plate and the vessel
are limited to three. An increase in the number of contact
points or pads will increase the number o~ impact fre~uencies
by the 6ame number.
The ratio of impact frequency to shaft rotation in
RPM between the bed plate and the Yessel, in the range of
contact points between at least 3 and up to approximately
10, is a function of the number of ~uppoxt points between
the vessel and the bed plate. Increase the number of contact
points increases the ratio of impact frequency to shaft rota-
tion speed in RPM.
