CA1081998A - Vibratory material handling apparatus - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The invention relates to vibratory material handling apparatus and more particularly to a dual exciter system drive for vibrating the apparatus wherein the exciters are positioned on either side of the center of gravity of the apparatus and direct vibrations at obtuse and acute angles, respectively, through the center of gravity of the apparatus, the arrangement being such whereby the vibratory force exerted by each exciter may selectively be varied so as to cause the apparatus to vibrate vertically, or displaced from the vertical, so as to convey in one direction or the opposite direction. The arrangement is such that the spring system connecting the exciters to the material-handling apparatus acts as isolation springs when the vibration generator associated therewith is inoperative, and as tuned natural frequency systems when the vibrator is actuating. The invention also provides a shakeout screen and sand lump breaking apparatus combined into a single unit, thereby providing an apparatus particularly useful in removing foundry sand from castings and breaking down lumps in the sand to permit the reuse thereof.

Description

~015 ~l998 VIBRATORY MAT~RIAL ~IANDLING ~PPAR~TUS
This application is a division of Canadian patent application Serlal No. 317,740 filed December 11, 1978.
BACKGROUND OF THE INVENTION
The use of more than one vibration c~ellerator associatecl with vibratory material handling apparatus to provide selectable conveying directions is not new. For example, U.S.
patents 2,712,45~ (Edward C. Wahl, July 5, 1955), 3,793,780 (Albert Musschoot, February 26, 1974) and 4,025,419 (Albert Musschoot, May 24, 1977) show systems wherein electric motors rotate shafts each carrying an eccentric weight, with the motors being attached directly to the vibrating apparatus. The previous systems shown in said patents were "brute force"
systems requiring heavy duty motors to generate the vibratory forces necessary. Tuned exciter natural frequency systems were not used in such multi-vibration generator arrangemen-ts perhaps for the reason that such natural frequency spring exciter systems would continue to vibrate with the material-carrying part of the apparatus even thougll the vibration genera~or associated therewith had been de-energized.
Referring again to prior apparatus in this field, it . i ~ .
has been customary in the past to remove foundry sand from a casting through what is known in the industry as a shakeout - screen. Basically, this comprised a grating mounted for . ~ .
~` vibratory movement and the sand and cas-ting were placed thereon ;~ with the vibrations serving to remove the sand from tlle casting. ---~ A5 foundry sand is expensive, the sand so removed was rendered reusable by treating it in a separate lump breaking apparatus, often consisting of apparatus similar to that shown in the : , ' ':
30 Musschoot patent 4,025,419 referred to above.

SUMMARY OF THE PRESENT INVENTION

~- The invention in this divisional application in i-ts 1~81998 broader aspects pertains to a vibratory apparatus including an open top material-carrying member'havincJ a bed at the bottom.
Side walls extend upwardly from -the bed and end walls extend upwardly .Erom the bed with a screen at one end of the bed and a door at the other end of the bed. ~ grat:islc! ;.s On the matol~ial-carrying member and is positioned over the bed. Meclns mount the material-carr~ing member for vibratory movement and selectively operable means are provided for vibratlng the material-carrying member .in a first vertical direction to shake o.EE sand clinging to a casting plac'ed on the grating and to break down lumps of ~ , sand removed from the casting and falling to the bed. The vibrating means is selectively: operable to vibrate the material~
carrying member in a direction inclined toward the screen to ;~ ' `' cause lump-free sand to move through -the screen and to cause the ,:. casting on the grating to move off the grating. The vibrating' ~' '' means is selectively operable to vibrate the material-carrying .- ' ` member in a third direction to convey uncrushable material~on .~; :
the bed to and out of the door. Preferably à conveyor is positioned at the end of and below the grating to receive ~:`. 20 castings therefrom.

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. More particularly, as disclosed the preEerred .

~' apparatus includes two natural frequency exciter type drives '. positioned on either side of the center of gravity of the ~ ' , ~ :
, vibratory apparatus. The exciter mass of each excite.r assembly ~ ~ -- is connected to the vibratory apparatus through a spring system ;~:

~, - in which the springs have a rela.tively high spring rate in the direction of vibra~ion-generating movement of the exciter mass, , .
and a relatively low spring rate in a direction normal thereto.

, The exciter assemblies are arranged so that the direction of :: 30, vibration is along a line passing through the center of gravity .:
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of the material-carrying member, and inasmuch as the exciter members are positioned on either side of the center of yravity, such lines intersect at the center of qravity preferably at an ~i; angle of 90 degrees. When both exciter assemblies are operated, the resultant force on the vibratory material-carrying apparatus produces vertical vibrations. If the vibration generator associated witll one exciter assembly is de-energized, the other exciter assembly will produce vibrations at an angle to the vertical, i.e., one which produces conveying vibrational movement of the material-carrying apparatus. 'Ihe de-c~lergi~ t exciter mass will, because it is connected to the vibratory material-carrying apparatus by a spring system having a low spring rate normal to its operating direction, be in effect isolated from the vlbratory material-carrying member. ~lence, . ~ .
the exoiter mass of the de-energized exclter system will remain ~ ~ substantially motionless.

r The vibratory material-carrylng apparatus includes a ;
~: screen or grating on the top, on which a casting covered with ~` sand may be placed and when the apparatus is vibrating, the '; 20 grating acts as a shakeout screen freeing the casting of sand, with the sand so removed from the casting falling into a bed within the apparatus where the vibratory action breaks Up lumps ~; in the sand. By de-energlzing one of the vibration generators associated with one of the exciter assemblies, -the sand and ,' ' .
~` castings can be conveyed to a discharge for removal from the apparatus and periodically the other exciter assembly may be de-energized so that unbreakable material left over from the lump breaking operation may be discharged at the opposite end of the apparatus.

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' ~ 30 All of the foregoing will be more clearly evident from ~ the following descriptlon and drawings.

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~0~J ~98 F D~SCRIPTION OF T~IE DR~WIi~IGS
Fig. 1 is a side elevation~l view partly l~roken away and partly in section showing apparatll~ embodying the present invention;
Fig. 2 is an encl view o the appa.ratu~ shown in Fig. l; and Fig. 3 ~hows a modi~ied ~orm o mounting or the excitar assembly.

DESCRIPTION OF TH~ PI~'F~RRED Ei.~QDI~NT
Referring now to Flgs. 1 and 2 o~ the drawing.~
thexe 1~ shown a vibratory material handling apparatus includ- . :. ..
ing an open-top ma~ffrial-carrying member 10 having side walls 11 and 12, and end walls 13 and 14. The bottom 15 of the member 10 forms a bed having an upwardly slanting portion 16 leadiny to a screen I7 at one end of the member 10. ~t the .
opposite end of the member i~ a door 18 operable by ~ piston and cylinder device 19 which serve~ to pivot the door be-tween the open and closed position~ illustrated.
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:: The r.tateri~tl-carrying member 10 is supported or :

vibratory movement on isolation springs 20 ~upported on a base 21. The ~ide walls 11 and 12 havP downwardly extending portions 22 and 23. Suspended from the downwardly extending portions is a first exciter assembly 25` including a pair of .
I-beams 26 and 27 extending between the portions 22 and 23.

-:. A plurality of parallel coil springs 28 are provided with : .
:: each spring having ona end connected to one of the I~beams .~ ,; . , 26, 27, and having its other end connected to a second pair ... `- of I-beam~ 29, 30. Secured to and bet~een the I-beams 29 - and 30 is a vibration generator 31 including an electxlc .- 30 motor 32 carrying an eccentxic weight apparatu~ 33. Preferably, ~-the vibration ~enerator is o~ the type shown in Mu~schoot U.S.

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patent 3,35a,815 (Albert Musschoot, December l9, 1967), i.e., one where the degre~ o~ eccelltric Eorce g~neratecl wi~ll rotation of the weight can be varied between zero and maximum.

The I-beams 29 and 30 and the vibration generator 31 conAtitute an e~citer ma~s which is po~itioned on one side of the center of gravlty indicated at 34 of the material-carrying member.
~ second exciter as~embly 35 i9 ~uspended from the downwardly extending portions 22, 23 on the opposite side of the center of gravity as the exciter assembly 25. The second excitex assembly includes a pair of I-beams 36 and 37 extending from end to end of the apparatus like the I-beams 26 and 27, a plurality of coil springs 38 each secured at one end to one of the I-beams 36, 37, and at its other end to a pair of I-beams 39, 40 extending between the portions ~2, 23 like the I-beams 29, 30. A vibratlon ~enerator 41 is : . ~
~- secured to and located between the I-beams 39 and 40, the ' vibration generator 41 being of the same type as the vibration ~ generator 31.
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Secured to the top of the material-carxying member ~- 10 is a grating 45 positioned to receive sand coated castings.
, The grating 45 iB located over the open top of the material-carxying member and is supported by the su~porting structure 46, in turn carried by the member l0. On the outer side of the screen 17 there is provided a chamber 47 having a chute . .
,~ 48 for dlrecting sand coming from the interior of the , material-carxying member into a suitable conveyor or container.

; The vlbration generators 31 and 41 are equal in force-generating ability and thus when energizea the ex.citer : , .
mass 25 will vibrate along the line 50 parallel to the axis of the springs 28 and intersecting the center o~ gravity 34.
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The llne 50 as illustrated extencls at an acute angle to the horlzontal. Similarly, when the e~citer mass 35 is energized through energi~ation of the vibration generator 41, that exciter mass will vibrate along the line 51 which ext~nd~ parallel to the a~is of the coll spring~ 38 an~ also in~ersects the center o~ gravity 34. The line 51 ~xtends at an obtuse angle to the horizontal.
The exciter assemblies 25 and 35 are tuned natural frequency system3, i.e., the rate of rotation of the eccentric weights of each vibration generator approaches the natural frequency of the coil springs, actin~ in compre~sion, associated with each assembly. When both are operated with equal orce, the direction of vibration o the materi~l-carrying member 10 will be vertical, i.e., in a direction bi~secting the angle 53 formed ~y the lntersection of lines ., 50 and 51, such direction o~ vibra-tion being indicated by the arrow 52. I the vibratory ~orce o one of the vibration generators is reduced (as is pos~ible with the sy~tem shown in the Mus~choot patent 3,358,815), the line of direction of vibration of the material-carrying member 10 will mov~ from the vertical to a slanted position toward that exciter assembly subject to the reduced ~orce. If one exci~er ' assembl~, or example assembly ~5, is de-energized completely, vibrations will be in the direction of the arrow 5~, while i th- other exciter assembly 35 is the one de-enargi7ed, .
` - the vibrations ~ill be in the direction of the axrow 55.
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Vibrations in directions between 5~ and 52, or between 55 ~-~ - and 52, ~ay be achieved by only partial reduction of the vibratoxy force.

Coil ~prings 28 llave a relatively high ~pring rate along their axis and a much lower s~rin~ rate in a irection normal to their axis. Thus, when vibration 6.

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' : : '- ' , ' "' - 108199Ei generator 31, for c~ample, is de-energized and exci~er assembly 35 is ~roducing vibrations in tllc~ d:irection o~
arrow 5~, that dlrection is norm~l to the axis of th~ coil spring~ 28 and thus at thcir lower spring rate. In this situation, the springs 28 act as isolation syrings isolating the exci-ter mass comprising the I-beams 29, 30 ancl vibration g~nerator 31, from tlle rest o~ the vibrating apparatus.
Thus, that exciter mass will remain substanti~lly sta tLonary~
The oth~r exciter mass com?rising the I-hei~mr, 3~, lO ~Ind vibration generator 41 are subject to the same phenomena and when that vibration ~enerator is de-energi2ed while the vibration generator 31 is o~erating, coil sprinys 38 will act as isolation springs in a similar ~lanner.
It will be noted that when both vibration generators 31 and ~1 are operating e~ually to produce vibratory force, the material-carrying member 10 will he vibrating in a vextical direction as indicated by the line 52. In this situation, the lower ends of springs 28 will be moving in a direction parallel to the line 50 while the upper end~ of those springs will be moving ln a direction parallel to the line 52. Similarly, the lower ends of springs 38 wiIl be moving in a directlon par~llel to the line 51 while their upper ends will be moving ~ertically parallel to the line 52. ~s noted above, the spring rate of the springs is lower in the ~irection normal to their axes and thus with par-t o~
the sprir.gs op~rating in an off-a~is direction, the overall ~ spring rate of the springs 28 and 3~ will ~e lower than - their spring rate ~hen operating only along their axes.
Under the conditions described, ~o~h exciter assemb1ies ~0 will be actir.g togetsher to pxovi~e ,he ~orce to vibr~te -the material-carrying me~ber vertically. ~o~evar, when one of ::

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~081998 - the vibration generators, ~or example the vibration generator 31, is moved to zero output, the springs 38 will be operat-ing entirely along a line parallel to the line 51, and hence the spring rate for those ~prings will be higher than when both vibratlon generators are operating equally. Thus, exciter member 35 is actuating the total mass o the ma-terial-carrying member, i.e., is providing the sole orce for vibrating the material-carrying member. However, the spring xate of the springs 38 i9 now at a maxim~ as both ends of the springs are moving along the same axis. This can then be de~igned so that the natllral frequency of the system, when only one exciter assembly is opera-ting, can still be in the resonant range.
In operating the device, a castin~ embedded in sand may be placed on the grating 45 and both vibration generators 31 and 41 activated. This will produce vibrations in a , ., vertical direction as indicated by the arrow 52~ The grating ,. . .
` 45 acts as a shakeout screen and sand will fall therethrough .. . .
onto the bed 15. Sand falling on the bed is of course `

subject to the vibrations generated which serve to break - UP 1UmPR of the sand and put it into reusable condition.

When su~ficient time has elapsed to accomplish removal of :.:
sand from the casting and the breaking up of lumps in the .. , .
removed sand, vibration generator 31 may be de-energized whereupon the material-carrying apparatus will vibrate in the direction of arrow 54, conveying the casting off the grating , ............................................... . .
45 and onto a belt conveyor 49, while the sand on the bed 15 will be conveyed toward and through tha screen 17 into chamber 47, out the chute 48, into a container or conveyor.
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Periodically, the vibration generator 41 may be de-energized -while vibration generator 31 is operating to conva~ accumula-tion of material and other un~rushable portions in a direction 8.

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to the right as ~hown in Fig. 1, and piston and cylinder device 19 operated to open the door 18 permi~tinc3 such accumulation to be conveyed out o~ the apparatus to a suitable container.
The apparatu3 of the present invention can ~lso be used ~IS a continuou~ ~y~tem by ad~ust.in~ the vibr~t.ion ~enerator 31 60 that it is producing vibrations o le~s force than the vibration generator 41. Thi~ will produce a slow conveyin~ action from right to leEt, and the speed o~ the action can be easily adjusted so that castings on grating 45 and 3and on bed 15 remain, respectively, on the grating and bed suficiently long to remove sand ~rom the - casting and to break up the l~nps, and yet progress slowly toward the di~char~e (le.~t-hand) encl oE the apparatus.
Even in such continuous operations, it will be oun* advisable periodically to rever~e the direc-tion oE conveyin~ so a5 to remove uncrushable material throu~h the door 18.
It will be apparent to those s~illed in the art that the multiple tuned fre~uenc~ exciter system sho~m in the drawings can be used on apparatus other than sh~eout sand reclaiming combinations, inasmuch ai there is pro~ided a tuned ~requenay syste~ which can be easily and ~ccuxateIy regulated to produce maximum ox minimum vibrations in a direction producing conveylng action in one direction or the other, or no conveying action at all.
In ti`e event it is tllought ~lesirable to provide some ~uide means ~or the exciter Ma3ses, a simple lin~
arrangement such as ShO~I in Fig. 3 may be used. The ~` arran~e~ent include~ a bracket 56 secured to the I-beam 30 ~nd ~ivotally connected to a link 57, in turn pivotally connected to a second bracket sa ~ecurecl to the I-beam 26.

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Claims (2)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Vibratory apparatus comprising an open top material-carrying member having a bed at the bottom, side walls extending upwardly from the bed and end walls extending upwardly from the bed, a screen at one end of the bed, a door at the other end of the bed, a grating on the material-carrying member and positioned over the bed, means mounting said material-carrying member for vibratory movement, selectively operable means for vibrating said material-carrying member in a first vertical direction to shake off sand clinging to a casting placed on said grating and to break down lumps of sand removed from the casting and falling to the bed, said vibrating means being selectively operable to vibrate said material-carrying member in a direction inclined toward said screen to cause lump-free sand to move through said screen and to cause the casting on the grating to move off the grating, and said vibrating means being selectively operable to vibrate said material-carrying member in a third direction to convey uncrushable material on the bed to and out of said door.

2. The vibratory apparatus of claim 1 including a conveyor positioned at the end of and below said grating to receive castings therefrom.