US3544292A - Granular cleaner - Google Patents

Description

Dec. l, 1970 GRANULAR CLEANER Filed Jan. 1.9, 196s sheets-smet 1 Dec. 1, 1970 A. G. BOBINE 3,544,292

GRANULAR CLEANER Filed Jan. 19. 1968 3 Sheets-Sheet 2 INVENTOR.

13120D1970 y A. G. BOBINE 3,544,292

GRANULAR CLEANER Filed Jan. 19, 1968 3 Sheets-Sheet 5 fg@ l FU 79 i i i l i Q`\c 90; 906J VF ]/7'9/0 U 79 /ja 92a F 1 v 5 l i 63 /90 92C @../l! l m V79 7.

l V "V mi@ L United States Patent O 3,544,292 GRANULAR CLEANER Albert G. Bodine, 7877 Woodley Ave., Van Nuys, Calif. 91406 Continuation-impart of application Ser. No. 423,559, Jan. 5, 1965. This application Jan. 19, 1968, Ser. No. 699,198

Int. Cl. B24b 19/00, 31/00 U.S. Cl. 51-7 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to methods and apparatus for cleaning metal parts and the like of foreign material such as hard crusts or scale, or adhesive coatings of any kind, including remaining fragments or surface coatings of adhering hard material, or in certain foundry techniques the removal of whole cores, and also for cleaning the interior cavities of castings of the metal filaments or whiskers often caused by reason of intrusions of the metal into the sand core.

This application is a continuaton-in-part of application Ser. No. 423,559,71ed Jan. 5, 1965, now Pat. No. 3,380,195.

The problems incident to the cleaning of castings or stampings of foreign encrustations, sand core material, intrusion filaments, machining burrs, or excess metal ow, have not been solved in the past in a completely satisfactory manner, and some of these casting problems have, in fact, become aggravated with the modern trend toward harder and tougher core adhesives. The general object of the present invention is to provide novel methods and apparatus for solving these problems of metal parts surface conditions.

This invention is especially applicable to the removing of rust, and to general surface preparation prior to painting or plating.

One problem area of the prior art is that of breaking up and removing certain sand cores from castings. To facilitate core removal, the sand core is generally made up with weaker adhesive substance than would otherwise be desirable. To obtain more accurate castings, permit thinner walls, and improve tolerance control, it would be very desirable if a stronger plastic glue could be used. The problem heretofore has been the lack of a suitable method for removing such a core from the casting. Even when it has been possible to break the core from the casting, these plastic adhesives in the core sometimes leave coatings on the casting of such hardness that they are very diicult to remove.

Another problem has been to remove from the insides of the castings the common metal filaments or whiskers resulting from intrusion of the metal into the sand core.

Objects of the invention are therefore to provide novel and improved methods and apparatus for cleaning stampings, castings and the like of foreign material such as hard crusts, scale, or adhesive coatings, including remaining fragments or surface coatings of adhesive core material, for breaking and removing whole cores from castings, and for cleaning the interior surfaces of parts of coatings, metal filaments or whiskers.

-An additional object is to clean off rust, oxidized oil, polishing rouge smut, etc., from various castings, stampings or machined parts, without the use of liquids or of air blast.

The present invention, in its most usual form, proceeds by resonantly vibrating an elastic system including a container enclosing the part while covered with a body of hard, loose, granular or particulate material, in some ice cases irregularly shaped grit, and in others, metal pellets with or without scrubbing qualities, and in some instances pleferably of high density, such as steel balls, or lead s ot.

A sonic wave or vibration generator is employed, and acoustically coupled thereto is an elastic vibration transmission means. This combination of vibration generator and elastic vibration transmission means has an acoustic coupling or output means embodying a box or similar container holding the part. The sonic generator is driven at a frequency which will set up in either, or both, of the acoustically intercoupled elastic vibration transmission means and part container, a sonic standing wave pattern. Standing waves can include resonance phenomena, and relatively large amplitude elastic vibrations of the part are therefore attainable under such conditions. The elastic vibration transmission means can be designed for various effects within the scope of the invention.

One desirable practice of the invention is to provide the vibration transmission means in the form of an elastic member of distributed constant type in which a resonant standing wave can be set up. This member may be intercoupled between the generator and container, but not necessarily so, for the generator can alternately be intercoupled between this member and the container. In the latter case, the vibration transmitting means transmits vibrations merely within itself, rather than to the part; but, primarily, to add an amount of stiffness reactance to the vibratory system for the purpose of balancing out forcewasting mass reactance. In either case, when the part is contained, and the generator driven at a frequency to resonate the system, the stiffness reactance of the vibration transmission means tunes out or cancels the mass reactance owing to the masses of the generator, of the part, the cleaning medium, and of the vibration transmission means itself, so that the vibration generator can easily vibrate the system including the part under sonic conditions of high cyclic acceleration, notwithstanding these otherwise force-consuming masses. Considering its function in this aspect, the vibration transmission means may aptly be termed an elastic stiness reactor. The vibration transmission means also contributes high Q to the vibratory sonic system, as Well as facilitating the vibration of the masses involved. The Q factor of vibratory systems will be understood to be a sonic ligure of merit analogous to flywheel effect in rotational systems, or sharpness of tuning in electronic systems.

Also, in some forms of the invention the vibration transmission means, or elastic stiffness reactor, in which the standing wave is established is deliberately intercoupled between the vibration generator and the load, so as to function as an acoustic lever. That is to say, as will be made still more clear hereinafter, in this case the vibration transmission means is arranged to have high vibration amplitude and low force at its coupling point with the vibration generator, and reduced vibration amplitude, but correlative force gain, at its coupling region near the part. From the acoustic impedance viewpoint, the vibration transmission means thus functions to match a relatively low-impedance generator to a relatively highimpedance load, i.e., part and surrounding particulate matter.

The sonic vibration generator and transmission means combination, for good operation, should have, at the container, an output impedance of the order of magnitude vof the vibratory impedance presented by the part and its environment. The expression impedance, as used herein, denotes the ratio of vibratory force amplitude to vibratory velocity amplitude. It will be seen that the desired conditions are met if the ratio of force to velocity at the output end of the generator and vibration transmission means combination, i.e., at the container, is

comparable with the required ratioof force to velocity in the part, at the submerged point, when the part is undergoing vibration. Under such conditions, good power can be transferred from the vibration generator into the part for llarge amplitude sonic vibration thereof against the acoustic resistance imposed by the body of particles in which the part is buried.

. To carry out the process, apparatus in one of the forms discussed briefly above is connected to a box with a clamp to hold the part extending into the box. The part yis aixed to the box which is subsequently filled with a body of particulate matter. Thus, upon operation of the device, the part and the box vibrate together relative to the body of loose particles. Thus the box becomes part of kthe resonant system, so that ,the loose particles are vibrated from contact with the walls in addition to their contact with the part. The box can also be open at the top and bottom with the cleaning particles flowing through in a continuous stream. This provides means for removing the loosened portions of the part and the fur.- nishing of fresh particulate cleaning material throughout the entire cleaning cycle. It is believed the invention will be better understood fromy the following detailed description and drawings, in which:

FIG. 1 is a side elevational view of another form of the invention, fragmentary portions being broken away to reveal underlying parts in section;

FIG. 2 is a vertical plan section taken in accordance with the line 2 2 of FIG. l; k

lFIG. 3 is a transverse section taken on line 3-'3 of FIG. 2;

FIG. 4 is a diagrammatic view of the apparatus of FIGS. 1-3, representing the apparatus as though seen in plan, and including a standing wave diagram;

FIG. 5 is a diagrammatic View of the part under treatment in the system represented in FIG. 4, and showing a standing wave diagram representative of vibratory action in the part;

FIG. -6 is a view similar to FIG. 3, but showing a modication;

FIG. 7 is a diagrammatic view representing the part of FIG. 6;

FIG. y8 is a diagrammatic view similar to FIG. 4 but showing a modification; M

p FIG. 9 is a diagrammatic view representative of the part under treatment in the system of FIG. 8, together with a standing wave diagram;

FIG. 10 is a diagrammatic view illustrative of a modication of the system seen in rFIG. 4;

FIG. 11 is a view similar to FIG. 10 but showing another modication; and

FIG. 12 is a view similar to FIG. 10 but showing still another modification.

In FIGS. 1-3, a part to be cleaned is indicated generally and diagrammatically at '90. As shown in the drawings, this part, which may be of generally rectangular outline, is vertically disposed, and is engaged at its Y midregion by a clamp plate 88. Also, in the illustrative embodiment, a preferred hydraulic type ofV clamping means is shown and is indicated generally by the numeral 92.,This hydraulic clamping means embodies a cylinder or cup 93, drilled as at 94 to receive and pass the tie rods 87. The cylinder or cup 93 has a bottom wall 95 which is engaged against the adjacent side face of bar 63. The opposite end of cup 93 is enclosed by a wall 97, the central portion of which has a cup-like part 98 formed with a central bore 99. Spacer sleeves 87a are placed on tie rods y87 between wall 97 and plate 88. `A piston 100 works within the bore of cup or cylinder 93 and has a central stem portion 101 extending through and packed within bore 99, its extremity carrying, by means of loose pivot 102, a clamp pad 103 adapted for engagement with the side of part 90 opposite from the side engaged by the aforementioned clamp plate 88. Stem 101 has a ball end, as illustrated, engaging in a spherical seat 104 in pad 103, so that the pad 103 is free to accommodate 4 itself to the surface of part 90. Hydraulic fluid under pressure, from a suitable pressure source, is introduced into the inner end of cup 93 via fluid line 10S to apply the clamp, such pressure lluid of course moving piston to the right, as viewed in FIG. 3, so as to clamp the part. Hydraulic fluid on the opposite side of the piston is exhausted at this time via a passage 107 and a hydraulic line 108. The clamp can subsequently be released by introducing hydraulic uid under presure into cup 93 via line 108 and exhausting hydraulic nid in back of the piston via line 105. Suitable pressure source means, control valve and uid lines for this purpose are well within the skill of the art and need not be illustrated or further described herein. If desired, the part can alternatively be left loose (with the medium) within the box by releasing the clamp pressure, or by not having any clamp provision at all, such that the part vibrates freely with the medium.

A box 110 for containing a body of particulate matter 111 is erected in the region to be occupied by the part, and may have suitable access doors, or an open top, through which the part may be introduced and positioned for engagement by the above described clamping means. The box is attached by welding or the like at 96 to the walls of clamp 92.V A hopper 11Z`directs the cleaning particles 111 in a continuous stream into the box 110. The particles together with tht removed portions from the part exitinto hopper 1.13 at the bottom of the box where the dirt particles are filtered from the cleaning ones. The cleaning particles are then recirculated to the top hopper 112..

From the foregoing description it will be evident that the vibration generator 79 engages the side of the bar 63 atthe midpoint of the bar, exerting an alternating force component F on the bar 63, along a horizontal direction line normal to the bar at its midpoint. The generator 79 is driven by motor 71 at a frequency such that the a1- ternating force component F which it applies to the bar excites and maintains a resonant transverse standing wave t in the bar V(see the diagram of FIG. 4), preferably, or usually, a full-wavelength standing wave. FIG. 5 represents the part 90, and alongside thereof is shown a fullwavelength transverse standing wave diagram u, indicative of a transverse standing wave set up in the part 90 by reason of the vibratory motion of the clamping point between the bar and the part. Standing wave t is characterized by nodes n (regions of minimized vibration amplitude), large amplitude antinodes v (regions of maximized vibration amplitude) at the ends of the bar, and a center antinode v', whose amplitude is somewhat reduced from those at v because of the loading by the part 90 clamped to the Vbar at the midpoint. The reduced vibratory amplitude and velocity at v' is correlated with the alternating force component F at that point; and the impedance is higher at v than at v, where the vibratory velocity is greater, and the alternating force correspondingly reduced. It will be noted that, along with the reduction of amplitude at v', the nodes n shift inward somewhat from their normal or idealized positions at points located 25% of the length of the bar from its ends. As here shown, the nodes are approximately 30% of the length of the bar from its ends; and the mountings for the bar are at these 30%-of-length positions, as earlier described.

'Ihe bar 63 is an elastic vibration transmitting means, even though its elastic vibratory movements do not serve to transmit vibration from generator to part. It functions as a distributed constant vibration transmitting member, with elastic Waves or vibrations transmitted within or along itself, so as to contribute elastic stiifness reactance for balancing the mass reactances of the system. Thus, by permitting resonant behavior, the natural force-wasting properties of the large vibrating masses of the system are avoided.

In the` example of FIGS. 1-5, the part 90 is somewhat elongated, clamped in the middle, and a standing wave u is set up therein. It may of course be otherwise clamped, as at its end, and a somewhat similar standing wave attained. The standing wave u is a transverse standing wave. The wave or elastically vibratory action so set up in the part, surrounded by particulate matter, produces cleaning and core breaking and removal actions.

In FIGS. 6 and 7 are represented a case wherein the apparatus of FIGS. 1-3 is used to vibrate a part 90a of short dimensions, such that a full standing wave pattern may not be developed therein. However, the part 90a will be bodily vibrated at sonic frequency, and good cleaning action attained, even though some of the above mentioned advantages of standing wave action in the part may not be available. This is one particular application where the part need not be clamped at all; and wherein the box transmits the vibratory action to both the part and the medium as a totally loose work load. 'Ihe standing wave t in the bar 63 is like that of FIG. 4.

FIGS. 8 and 9 represent a case exactly like that of FIGS. 4 and 5, excepting that the frequency of generator 79 is doubled, so as to work at the second harmonic. The wave patterns t and u thus have two wavelengths rather than one wavelength as in FIGS. 4 and 5, and the frequency is doubled.

FIG. 10 is a diagrammatic representation of a modification wherein the vibration generator is interposed between the center portion of a vibratory bar 63a, like the bar 63 described earlier, and similarly mounted, and a part 90b. In this case, the part, which is again elongated, is arranged in general parallelism with the bar 63. The generator 79 will be understood to be mounted by any suitable fixture, not shown, on the center portion of the bar; and a clamp, represented diagrammatically at 92b, secures the generator to the mdregion of the part. Here, the generator directly exerts an alternating force component F in a lateral direction on the midpoint of the part. It exerts a similar alternating force component F' on the bar 63, causing elastic waves or vibrations to travel along bar 63. The generator 79 is run at a frequency to generate standing wave patterns b and c in the bar and part respectively, as indicated. Here again, the elastic bar, though functioning to transmit elastic vibrations, in order to have the necessary characteristic of a distributed constant vibratory member and to provide the system with elastic stiffness reactance so as to attain or approach resonance, does not function as a transmitter of vibrations from the generator to the part.

Reference is next directed to a further modilication, diagrammatically represented in FIG. 11, and wherein the elastic bar does have an important added property in acting as a transmitter of vibrations from the vibration generator to the part, and in serving as a useful acoustic lever in so doing. Here, the vibration generator 79 is mounted to the midpoint of the elastic bar 63, as before. However, the part 90e to be vibrated is mounted, through any suitable clamp, diagrammatically represented at 92C, at an extremity of the bar, where the vibratory bar normally has an antinode. Generator 79 is driven at a frequency to set up a transverse standing wave pattern t in the bar 63. Part 90e may be assumed to be vertically elongated, clamped at its midpoint to the bar, and fairly massive. It may then have a lateral standing wave pattern set up in it, much as suggested in FIG. 5. The substantial mass loading presented by the part may then reduce the vibratory amplitude of the standing wave at the clamping point between bar and part, as represented at vc. Full antinodes occur at the midpoint of the bar, as at v, and at the unloaded end, as at v. It will be seen that at the generator 79, and the antinode v in the bar, there is a certain vibratory velocity and alternating force magnitude F, and that from this point to the clamping point to the part, there is a reduction in vibratory velocity amplitude, which must be accompanied by a correlative increase in alternating force amplitude over the magnitude F exisitng at the generator. This acoustic lever effect is of advantage in transforming a condition of acoustic impedance at the coupling point between generator and bar which is low enough to permit easy drive by the vibration generator to a condition of substantially higher impedance at the coupling point to the part, such as permits the setting up of an effective, good amplitude standing wave in the part. This, of course, can occasionally be something of a problem when the part is large or intricate, and is buried in sand, lead shot, or the like. The acoustic lever effect is of great aid in combatting this problem.

FIG. 12 shows, diagrammatically, another modication, again incorporating an acoustic lever. The bar 63 and part are arranged as in FIGS. 10 and 1l; but the vibration generator 79 is attached to one extremity of the bar, where it applies to the latter the lateral force component F. A standing wave pattern t like that of FIG. 4 is achieved in this case, with reduction in velocity amplitude and gain in force from the region of generator 79 to the region of part 90, as indicated by the reduced amplitude of the standing Wave pattern at the part. In terms of impedance, there is a desirable gain in impedance in the bar from the region of the generator to the region of the part, permitting the generator, operating at a given impedance, to effectively drive a considerably higher impedance load composed of a sand-buried part.

It will be understood that while I have disclosed various forms and modifications ofthe invention, they are for illustrative purposes only, and numerous additional modifications will be suggested which are within the generic scope of the invention as defined by the broader of the appended claims.

I claim:

1. Apparatus for cleaning a part comprising:

a box section;

loose granular material in said box section;

clamp means for holding the part within said box section in said material;

an elastic element;

said box section, said clamp means and said elastic element being connected to each other to form a vibration system;

an orbiting mass oscillator coupled to said system;

and

means for driving said oscillator at a frequency such as to cause standing wave resonant vibration of said vibration system.

2. The device of claim 1 and additionally comprising means for continuously feeding said loose granular medium through said box section.

References Cited UNITED STATES PATENTS 3,380,195 4/1968 Bodine 51-7 3,031,802 5/ 1962 Leliaert.

2,840,923 7/ 1958 Behrens.

2,771,179 1 1/ 1956 Musschodt.

2,967,434 1/ 1961 Mahlfeldt et al.

3,336,701 8/ 1967 Moore 51-7 JAMES L. I ONES, .T R., Primary Examiner U.S. Cl. X.R.

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