US1704100A - Vibrating apparatus and method for its utilization for removing patterns and castings from sand molds - Google Patents

Description

March 5, 1929. Q B plKE 1,704,100

VIBRATING APPARATUS AND METHOD FOR ITs UTILIZATION FOP. REMOVING PATTERNS AND CASTINGS FROM SAND MOLDs Filed Aug. 8, 1927 Inventor Patented Mar. A', 1929.

Unirse i sra CLINTON B. PIKE, 0F .BRL'ENGHALL AIAIBAMA.r

VIBRATING APPARATUS AND Marston non irs u'rrnrzs'rron non nnivrovme PA.--

TERNS AND CASTINGS FRI-0M f lAllDy MOLDS.

Appli-cation filed August 8, i927. Serial No. 2411,395. 'y l My invention relates to a novel vibrating apparatus and to a method for its use to facilitate the removal of patterns and cast ings from sand molds. My invention is especially, though not exclusively, adapted for the removal of patterns used for forming sand moldsfor hollow cylindrical cast metal bodies such as cast iron pipe and the like, and l contemplate that it will prove etlicacious for freeing hollow castings, irrespective of their shape mold in which they were east and thereby facilitating their removal. l

ris my invention in the form herein shown is more particularly directed to the centrif ugal cast pipe art wherein sand molds are employed, its application to that will be more particularly7 described,r` without thereby intending to limit my invention to such particular use. y

In the present practiceof forming centrif ugal sand molds for pipe, the sand is rammed either by jolting or the pneumatic methods which result in the packing or con pression of the sand by blows or motion in the direction of the long axis'of the mold, and while this produces an exceedingly dense mold from which it is very diflicult to remove either the pattern or the Finished cast,- ing, nevertheless I have found that the sand, even though thus densely packed, will readily yield, sufficiently lto loosen its grip on l the pattern, to torces applied radially or transversely to the long axis of the pipe and it is this slightradial or transverse compressing of the sand which my invention makes use of to free the vpattern or easing and permit its ready removal from the mold.

My invention contemplates the utilization of a rapidly rota-ting vibrator, preferably in' the form of a disk or cylindrical body mounted concentrically on its drive shaft,y

which body is adapted, responsive to,cent-rif-V ngal or gyroscopic forces, to assume a worl ing position more or less out of line withthe axis of the hollow body to be vibrated thereby and which is free to have a planetary motion within the vibrated element as it travels, responsive to its rotating drive, in an orbit about the loiig axis of the hollow body. As the vibrator moves with more or less frietional engagement with the vibrated element it imparts thereto a rhythmieal vibrating or oscillatory Vmotion about its own long axis, said motion being in its extent governed by or composition, from the sand structure ofthe casting.

various vfactors such as the vrelative diameters of ,the vibrator and of the interior of the element vibrated, ,theY eP. M. of the vibrator head, and its weight relativeto the weight or inertia of the element to bevi brated. y y .i

By my improved method and apparatus I amable to producevibrations representing in number multiples of the R. P. .M. of the vibrator and these relatively short frequent impulses following the planetary movement of the vibrat'ortend to move the vibrated body rhythmically about its long axis, and actin a remarkably short time to `effect a sutlicfient radial compression of the sand which will loosenthe pattern or casting and facilitate its ready removal. kThis radial or lateral.compression of the sand in the mold needed to free the pattern is very slight and 'it takes place with maximum uniformity throughout thereby leaving the sand mold not only in ideal condition as to surface com'- pactnessfand smoothnessbut Valso Afree of any distortionthat may effect the uniform Obviously it is pos sible to free the pattern by an infinitelyl small enlargement of the mold diameter as both sand mold and pattern are inelastic elements and yet an exceedingly small enlargement of the mold makes it possibleto free and remove the pattern or finished `casting from the mold with remarkable ease. At the present such patterns and casting are removed with the greatest l.diilicult boththe pattern and the mold being subjected to very great forces in the effort to pull the pattern from the mold and it being usually necessary to cut away the sand from about the; casting by augurs,

drills and the like.

Some of the more important advantages of my invention over previous practice in the sand molding art are z-That the vibrating y element need not be attached to the element vibratedand is thus freely` movableinto and out of operating relation therewith; it is free to co-act circumferentially within the ele sent vibrated so as to work in all directions radially against 'the sand; it feeds itself automatically about the interior of the element vibrated and tends to cause al cylindrical element to follow it with a lag when loosened; it is adaptedto have ready relative adjustment lengthwiseof the element vibrated, if v,such be necessary, so as to work at different points lengthwise of the elongated vibrated element;

and it is susceptible of wide variation in structure, requiring only a rotating vibrator head suitable to frictionally engage the inner perimeter of the element vibrated and having a flexible drive shaft which will permit it to follow a planetaryniotion while at work. l

With the above objects in view my invention consists in the device and in the process for utilizing it which is hereinafter,more particularly described and claimed in typical embodiments thereof, reference being had to the accompanying drawings, in which F ig. 1 shows a vertical section through a sand mold for the casting of centrifugal pipe having therein a hollow pattern with which a single vibrator is shown in co-operative relation.

Fig. 2 Shows a Vmodification of my invention, wherein a plurality of vibrators are'carried by a flexible sectional shaft and adapted to co-.act at a plurality of points lengthwise of the element vibrated to impart synchronous vibrations throughout its length.

Fig. 3 is a plan view of l, showing vibrator unbalanced.

Similar reference numerals refer to similar parts throughout the drawings.

In the embodiment of my invention illustrated in Figs. l and 2, l show a mold flask 5, suitable for receiving a cylindrical or hollow pattern 6, between which and the flask sand is rammed to form a mold i' by any suitable mechanism which need not be described. The pattern shown is of a straight cylindrical type for casting a cylindrical body such as a pipe, tube or like hollow casting and therefore serves merely as a conventional illustration typical of any pattern or element to be vibrated. The interior of the pattern will be preferably cylindrical but this is not essential. After such pattern has been set in place and the sand tightly rammed about it, it has proven difficult to remove it from the sand mold and to overcome this I propose to make use of the mechanism which will now be described.

Above the mold l dispose a rotary motor or drive mea-ns 8, preferably an electric motor, and in order to produce relative axial movement between the motor and the flask l .provide as the simplest means an I-beam guide 9 which is engaged by a slide bracket 10 carrying the motor and supporting the motor with its shaft substantially concentric with the pattern. A shaft 1l driven by the motor is adapted to depend into the pattern and carries fast on its lower end a vibrator head 12, which can be balanced or unbalanced on its shaft. flChis head can be made up in many ways and will have a diameter less to the desired degree than the diameter of the pattern, and a weight which will be varied in accordance with the duty required. As shown in Fig. l, the head comprises a metal cylinder 12 mounted concentrically in balanced relation on the shaft 1l between plates 13 which are secured by nuts 14 and overhang the cylinder so as t receive and hold in position between them an annular' tread eleA ment l which can be of any material best suited for the duty contemplated. Preferably.` the shaft 11 will provide suticient {lexibility for the head, as it is rapidly rotated, to move laterally until its tread portion engages the inner circumferential wall of the pattern or element to be vibrated. A frictional engagement between the head and pattern will result and will produce a planetary movement of the rotating head as it travels about the pattern. As the head moves it imparts lateral or radial vibrations to the pattern tending to cause the axis of the pattern to move outwardly along a spiral path thereby eliecting a slight radial compression of the surrounding sand. The number of rotations of the head in completing its orbit will be determined by the relation ofits circumference to the inner perimeter of the pattern or element vibrated and for each rotation of the head there will be obtained a plurality of vibrations dependent on various operating conditions. By raising the head it can be caused to act on the pattern in various positionsv lengthwise thereof and as soon as the pattern is loosened at all, if it is cylindrical, it will tend to rotate and follow the head responsive to the frictional engagement therewith of the head, and when freed it can be stripped with ease.

lt will be seen that, as the head l2 is rapidly rotated, and is brought into frictional engagement with the wall the pattern 6, the inner surface of the pattern 6 serves as a track for the rotating head l2. Ordinarily, the head 12 is brought into frictional engagement with the inner surface ofthe pattern immediately upon starting the motor S, due to its own centrifugal force. l have found, however, that it is sometimes necessary,' in order to secure immediate frictional engagement, to laterally displace the shaft sufficiently for the head to come in contact with the inner surface of the cylinder. (hice in contact., the inner surface of the pattern serves-asa track or race for the head l2 upon which it runs. As the head l2 runs about the inner surface of the pattern, it exerts a centrifugal force radially against the wall o the pattern which is represented by the following formula:

where il] represents the weight of the head in pounds, o the linear velocity of the center of gravity of the head l2 and its connections in feet per second, g the constant 32.1711, and lt the radius or" revolution of the center of gravity in feet. This radially directed contrifugal force serves to symmetrically comsoy pressthe sand about the pattern until the pattern loosened.`

In Fig. 2, i show the vibrator head with a hole Q?) to uuluilance it. Such unbalancinn` will not change the actionv above described but will changjethe character of thevibra* tions. j f

ln Fig. 3 l. have shown a device adapt-cd tosimultaneously 'ibratc a pattern. or` liuisl'ied casting at various levels, thus expeditingthe-worlr of frceingthe pattern or rasting from the sand mold. Here the motor 8 issupported by a suitable adjustable support 16 and has a shaft 17 connected by a flexible joint 1S to a shaft sectionjl) carrying,` a rotating vibrator' head 220. ln like manner the shaft section 19 lis connected by a flexible joint lSivith a shaft section 2l and it in turn by a flexible coupling 1S with shaft section 22, each shaft section carrying its vibrator' 20. This device is lowered into the cylindrical pattern or iinished casting and rotated when it will have the plam-taryv movement described, and by engagement with the -inner walls with the pattern or casting; produce a multiplicity of radially directed vibrations and which will be represented by a high multiple of the rotation of the shaft itself and these will gradually act on the pattern or casting to radially compress the sand i'nold su'lliciently to free the pattern or tasting from the sand and permit its ready removal. The effect produced by the rotating traveling head on the pattern or casting may or may not be truly vibra'tory but certainly it causes such a displacement of the element acted upon in all directions in the plane of the heads rotation that the sand is uniformly compressed on all sides of the said element. The vibrator head shoivs here a tread l5 of such character that when the head is centrifugally disposed the frictional engagement oY if the tread l5 with the vibrated element will cause the head to travel about the inner peL rimeter of the. element Whatever its shape and as it moves to cause the displacement of the element for the purposes desired. The vibra-v tor must be subjected to centrifugal forceto cause it to perform its work, and this can be accon'iplished by its motion about an axis whether or not it be at the same time rotated about its own axis, and it can be designed as it swings around and frictionally engages the Work to impart the desired vibration and motion thereto.

While l have shown my invention in but two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible to various other changes and modifiations, without departing from the spirit thereof, and l desire. therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specilically set forth in the appended claims.

Having thus described my invention, what claimas new and desire to securezby Letters Patenhis f f l. In an apparatus of the character described, a vibrator, drive means therefor, and a hollow element having its vinternal perimeter frictionally engaged by the driven vibratory to radially displace it.

2. l'n an apparatus of'tliocharacter described, a vibrator, idrive means therefor which displace it. responsive to centrifugal force, and a hollow elen'ientihaving its internal perimeter frietionally enga ,red'byl rthe driven vibrator to Alaterally displace said ele ment and to cause progressive movement of the vibrator about theelenients perimeter. y

'2"3. ln an apparatus of the character described, a vibrator, a flexible drive sha'ft for rotating said vibrator and supporting it free Ior lateral displacement, and a hollow' element to be vibrated having' an internal perimeter about which the vibrator progresses responsive to friction and centrifugal force and which tends to be disposed in the direction in which the eentrifugalforce is exerted thereon. i

l. Apparatus according to claim 3, in which the vibrator comprises a plurality of vibrator heads mounted in spaced relation along' said drive shaft.

5. ln a process for the loosening, free for removal, of patterns, castings and the like from sand molds, the step Which consists in subjecting thearticle to be removed to internal force exerted outwardlyand progressively about its internal perimeter.

6. `The method of loosening; a hollow cylin-k drical pattern from a sand rmold Without distortion of the sand which comprises, subjectingthe inner urface ofthepatternv to a relatively high frequency radially directed vibratory force, said force acting circumferlli() entially around the inner surface of the pattern. f

7. The method of loosening a hollow cylini drical pattern in a sand mold Without distor' tion of the sand which comprises, subjecting the inner surface of the pattern to a relatively high frequency radially directed vibratory force, said force being distributed circumferentially and longitudinally of the pattern. i

8. The method of looseninga cylindrical pattern. in a sand mold Without distortion of the stand which comprises, symmetrically enlarging` ther mold around therpattern by a relativelyhigh frequency vibratory force directed radially against the inner surface of the pattern.

9. The method of sand molding, which consists in compacting the sand about a pattern to form the initial mold, then subjecting the pattern to a vibratory action applied substantially uniformly about it thereby to symmetrically enlarge the mold sufficiently to release the pattern for ready removal.

tern, a motor 'for driving the rotary member47 Y.Y und flexible means connecting the motor and rotary member. i

ll. in apparatus ttor loosening` a hollow eylinclriez l pattern from a sand mold, a rotary member loosely fitting' Within the pattern. a motor for driving the rotary member, flexible means Connecting the motor and the rotary member, and means providing rela tive longitudinal movement of the rotary member and the pattern While rotating.

l2. In apparatus for loosening a hollow cylindrical pattern from va sand mold, a rotary member Within the pattern, a motor havine its axis of rotation in axial alignment wir-li the pattern, and flexible driving means connectingvthe motor and the rotary member.

13. In apparatus for loosening hollow Cylinders in saiclmolds, a rotary member clisposed Within the hollow7 of the cylinder and adapted to track around the inner surfaee thereof, and means for driving the rotlfiry member. y

In testimony whereof I affix my signatiire.

CLINTON is. PIKE.

Images