USRE21046E - Apparatus fob producing molds - Google Patents

Description

April ll; 1939. H. F. HAGEMEYER Re# 21,946

l APPARATUS-`FOR PRODUGING MOLDS Original File-'d June 29.. 1936 2 Sheets-Sheet 1 i f Ilu lull F APY l1, 1939. y H. F. HAGEMEYER Re. 21,046

APPARATUS FOR PRODU ING MOLDS Reissued Apr. 11, 1939 UNITED STATES Re.' 21,046 PATENT OFFICE APPARATUS FOR PRODUCING MOLDS Henry F. Hagemeyer, Chicago, Ill., assignor'to Castings Patent Corporation, Chicago, Ill., a

corporation of Illinois Original No. 2,101,677, dated December 7, 1937, Serial No. 87,923, June 29, 1936. Application for reissue April 27,

` 14 Claims.

The invention relates to molding apparatus and is particularly adapted to be embodied in apparatus for producing molds comprising calcined gypsum and asbestos pulp.

In `the production of molds of the kind de` rial preferably comprises eighty percent (80%) by weight of calcined gypsum and twenty percent (20%) of asbestos pulp. After the water and molding material are placed in the flask it is necessary to agitate the molding material and the water violently so that a homogeneous mixture will be obtained. The agitation must be such that the mixture ischurned and impacted against the match plate and the pattern. After the molding mixture has been violently agitated in the manner described, the molding material is permitted to set. The mold is then withdrawn from the flask by means embodying the present invention, the mold being then subjected to a drying operation before any molten metal is poured into it. Fused metal at relatively high temperatures may be poured in the`molds and ,the resulting castings will be found to be extremely perfect in configuration. It may be mentioned that the gases attending the pouring operation vent through the molding material which is extremely porous when dry.

As indicated above, the present invention relates to apparatus for withdrawing the molds from the flask. 'I'he apparatus, in its preferred form, includes means for subjecting one side of the mold to a partial vacuum so-that the differential in pressures on opposite sides of the mold cause it to be displaced relative to the flask and the match plate. This method of withdrawing the mold from the flask is exceedingly advantageous as the molds are not broken or otherwise deformed.

As stated, the mold is withdrawn from the ask and match plate before it is dried. At this stage of the process, while the material is neces. sarily somewhat set, it is still quite soft and can `be easily deformed or injured.

My main object is therefore to withdraw such4 1938, Serial No. 204,694 A(Cl. 2%;190)

still another object is to withdraw the mold both from the ask and the match plate in a single operation, and preferably to perform such operation with the ask and 'match plate in the inverted position to allow easier handling of the mold, and to reduce the differential pressure required to a minimum.

Other objects and advantages of the present invention will appear as the following detailed description progresses, reference being had to the accompanying drawings.

. Fig. 1 is a side elevation of apparatus embodying the invention, a match plate, a flask and a mold being shown in cross-section to illustrate the operation of the apparatus;

Fig. 2 is a top plan view of a suction plate which is utilized to subject one side of a mold -to a partial vacuum;

fFig 3 is an enlarged fragmentary section taken on line 3 3 of Fig. 2;

Fig. 4 is a section taken on line 4--4 of Fig. 2,

a mold, a flask and a match plate being shown in connection with the suction plate;

Fig. 5 is a vertical section taken through an improved flask` and match plate;

Fig. 6 is a section taken on line 6--9 of Fig. 5;

Fig. 7 is' a section taken through a valve which forms part of the improved apparatus; l

Fig. 8 is a section taken through another valve which also forms part of the improved apparatus; and

Fig. 9 is a perspective view of a mold which has been withdrawn from the improved flask.

I prefer, as will be described in detail hereafter, to withdraw the mold from the flask and match plate simultaneously, such ask and match plate being secured together to form an integral unit. It will be appreciated, however, that my method'and the operative principles embodied ,in my preferred apparatus illustrated and particularly described may be employed either to separate'the mold from the match plate alone or from the flask alone as well as from both at once. 'I'he ask and the match plate are both mold forms, and hence the term mold form will be used in this specication in a generic sense to designate either a match plate, or a ask, or both match plate andy ask, or equivalent structure.

Referring to the drawings wherein a preferred embodiment of the invention is illustrated, the reference character III designates a base' plate adapted to restupon any suitable support such as the floor of a Afactory (Fig. 1). Projecting upwardly from the base plate III and secured thereto is a post Il to which a bracket I2 is bolted. The bracket I2 is provided with lugs I3 having grooves I4 adapted to receive the ends of a match plate Il. Any vdesired alternative form of flask and match plate holder or support may, of course, replace such bracket and lugs. -Detachably secured to the match plate I5 is a flask I8 and disposed within the match plate I5 is a mold I1` abutting against the bottom surface of the match plate I5. It will be noted that the'match plate I5 is provided with a pattern I8. The construction of the match plate I5 and the ilask I8 is described in detail in my cio-pending application, Serial No. 87,922, flied June 29, 1936.

Disposed beneath the bracket I2 and gned with the mold I1 is a suction plate or over 28 secured to the upper end of aV vertically disposed rod or plunger l2l which is slidably journaled in a bearing 22 secured to the post II. A rack 23 xed to the plunger 2| meshes with a pinion 24 which may be rotated manually through the medium of a handle 25. It will be readily understood that if the handle 25 is rotated in a clockwise direction (Fig. l) the suction plate 28 and the plunger 2| will be lowered'and that if lthe handle 25 is rotated in the opposite direction, the suction plate 28 and the plunger-2| will be elevated. Obviously, the suction plate 28 may be elevated until its 'upper surface abuts against the bottom surface of the mold I1.

As best shown in Figs. 2, 3 and 4, the suction plate 28 has a rectangular member 28 disposed around it, the rectangular member 28 having la beveled surface 29 at its' upper edge. The suction plate 28 is provided with an integral rib 88 extending around it, the rib 88 being adjacent the beveled surface 28 of the member 28. This rib 38 is sufficiently sharp to'penetrate the surface of the soft mold, which may be slightly irregular, enough to eect a vacuum seal about the central portion of the plate, as will be explained more fully hereafter.

vUpstanding from the surface of the plate are closely spaced mold engaging projections with depressions interposed therebetween. In the pre- 'ferred form shown, these projections arearranged as a plurality of ribs extending lengthwise of the suction plate arid alternating with grooves 8I which open into a deeper groove 32 cut into the upper face of the suction plate 28. It will be noted that the grooves 82 extend substantially the entire distance between oppositely disposed parts of the sealing rib 88. The upper surface of the suction plate 28 is preferably provided with a recess orV depressionv which is preferably deeper thanv the grooves 8l, and which may receive the upper end of a conventional sprue forming projection upstanding from the match plate (not shown) of the cope mold section, and which extends entirely through or `almost through the mold section. vIn the case illustrated the sprue would be formed in the other complemental mold section not illustrated. The groove 82 opens into a bore 81 in the suction plate 28. The bore 81 communicates with a bore 88 in the upper end of the plunger 2| andthe 'bore l88 communicates, in turn, through a pipe 88 with one end of a flexible hose 48. The other end of the flexible hose 48 communicates with one opening of a three-way valve 42. Another opening of the valve 42 communicates through a pipe 43 with an opening in a three-way valve 7.5Atthelowerendofthepipe52,`aval ve58is ano-ic provided. The purpose oi' this construction will presently appear. l

As stated above, one opening of the valve communicates with the pipe 48. A second opening of the valve 45 communicates with the atmosphere through a pipe 58. 'I'he third opening of the valve 45 communicates through pipe 88 with the discharge port of a vacuum pump 8| which .is mounted on a bracket 88 secured to the post I I.

The vacuum pump 8| is driven by means comprising a pulley 84 hxed on a shaft 85 which forms part of the vacuum pump. A belt trained over the pulley is also trained over a pulley 81 mounted on the shaft of an electric motor 88 which is mounted on the base plate I8. The inlet port of the vacuum pump 8l is connected through a pipe 18 with the tank 58. A vacuum gauge 12 communicates with the pipe 18 and indicates the pressure obtaining within the tank 58. A pipe 13 which communicates with the tank 58 at its lower end is provided with a valve 14 which may be openedsoV that any liquid in the tank 58 may be drained therefrom. The three- way valves 42 and 45 are provided with valve handles 15 and 18, respectively, the free ends of the handles 15 and 18 being pivotally connected to a link 11. Pivoted to the free end of the valve lever 15 is a second link 88 which is also pivotally connected by a pivot pin 8l to one end of a foot treadle 82 which is pivoted intermediate its ends on a pin 83 projecting from a bracket 84. The bracket 84 is fixed to the base I8; Pivoted to the link 88 intermediate its ends is a small link 88 which has one end of a tension spring 88 secured to it, the other end of the tension spring 88 being secured to an eye bolt 89 which is screw-threaded in a bracket 98 mounted on the base I8. 'I'he spring 88 normally holds the valve levers or handles 15 and 18, the link 11, the link 88 and the foot treadle 82 in the positions wherein they are shown in full lines in Fig. 1. However, if the operator steps upon the outer end of the foot treadle 82 and displaces `it into the positionwherein it is shown in dotted lines in Fig. i, the links 11 and 88-will cooperate to displace the valve handles 15 and 18 into the positions wherein they are shown in dotted lines in Fig. l. This displacement is against the action of the spring 88.

The operation of the above described apparatusv is substantially as follows: It is assumed that the mold` I1 has been formed by practicing the I ethod described in my co-pending application.

N0. 87,922, leszl June 29, 1936, and that it has not been subjected to the drying openation described in my oo-pending application, Serial No. 91,891, led July 22, 1936. However, the mold has been permitted to set and the match plate I5 has been inserted in the'grooves I4 as illustrated in Figs. 1 and 4. The foot treadle 82 and the valve handles 15 and 18 are in the positions wherein they are shown in full lines in Fig.

1. The pipe 88 then communicates with the atmosphere through the valve 45, and the pipe 58 but is adjusted so that the pipes 88 and 58 do not communicate with the pipe 43. 'Ihe tank 58 communicates with the flexible hose 48 through the pipes 81 and 48, the T-tting 5I and the valve 42. The valve 42 is then adjusted so that the pipe 45 and the iiexiblchose 48 do not communicate with the pipe`48. The valve 53 has been adjusted so that some air may ow through it and the pipes 52 and 41 to the tank 58. It should be understood that vthe valve 88 may be adjusted to control the minimum pressure that will obtain in the tank 50 when the vacuum pump BI is in' operation.

Assuming that the vacuum pump B'I is in operation and that the mold l1 is in'the'position wherein it is shown in full lines in Fig. l, the operator manipulates the handle to bring the suction plate 20 into contact with the mold I1 (Fig. 4). Sui'llcient pressure is exerted so that the sealing rib on the plate 20 will be engaged firmly and contiguously over its entire perimetral length with the soft mold surface, and because of the presence of slight irregularities the rib 30 will be made to penetra-te slightly or to indent the surface of the mold to insure a tight vacuum seal. A partial vacuum will be established immediately between the upper surface of the suction plate 20 and the adjacent surface of the mold I1. The entire bottom surface of the mold I1 will be subjected to this partial vacuum as air will be exhausted through the grooves 3I and 32 and the bore 31.

As the differential pressure is created on the opposite sides of the mold the soft material will be forced against the plate 2li. The projections umtanding from this plate, herein illustrated in the form of parallel ribs alternating with the grooves 3|, will support the back surface of the mold over distributed, closely spaced areas so that the soft mold will not be buckled or fractured nor will pieces of the mold be broken off. If such mold supporting engagement were not provided by the projections, the soft mold would be bowed into the vacuum space on the plate A2li and the material would be squeezed against its surface to fill the vacuum cavity. The projections or ribs will be slightly embedded in the mold surface by pressure of such surface thereagainst, but they are spaced closely enough so that the mold material will have suillciently distributed support to prevent mold material' entering or clogging the grooves 3| to any appreciable extent, and a substantially niform. vacuum or differential pressure can therefore be maintained throughout the grooves. v

The operator will then manipulate the handle I 25 to lower the suction plate 20 and the mold I1 will follow the suction plate as a result of the -dlfferential in pressures obtaining between the upper and lower surfaces of the mold. As soon as the suction plate 20 has been lowered sufficiency to permit the operator to handle the mold without bringing it into contact with the ask I0, the operator steps upon the foot treadle 82 so that the valve handles 15 and 16 move into the positions wherein they are shown in dotted lines in Fig. l. The pipeGIl then communicates with the pipe 43. and the flexible hose 40 through the valves and 42 but the valve 45 is then adjusted so that the pipe 80 does not communicate withl the pipe 58. The valve 42 is then adjusted so `that the pipe k46 does not communicate with the pipe 43 or the flexible hose 40. Obviously, the exhaust opening from the vacuum pump 6I is then connected to the bore 31 and the grooves 3| and 32 through the pipe B0, the valve `45, the pipe 43,.the valve 42, the flexible hose 40 the pipe 39 and the bore 38 so thatthe partial vacuum between the suction plate 20 and the mold I1 is broken and a.- pressure above atmospheric pressure is applied to force the mold away from the projections or ribs which were forced against and slightly embeddedin the mold surface. 'Ihe operator may then remove the mold I1 from the -suction plate 20 with little effort and without danger of part of the soft mold adl the drying apparatus.

hering to the plate 20 and being broken from the mold proper, and he may then place it in Meanwhile, the operator has released the foot treadle 82 to restore the apparatus to its original condition so that the above described cycle of operations may be repeated. l

During the operation of subjecting the mold I1 to a partial vacuumv through the medium of lthe suction plate 20, some water is withdrawn from the soft, moist mold I1. .This water passes into the tank through the flexible hose 40, the valve 42 and the pipes 46 and 41. After an undesirable amount of water has collected in the tank 50, it may be drained therefrom by opening the valve 14. i While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modications. Changes therefrom, in the construction and arrangement may be made without departing from the spirit and scope of thel invention as disclosed in the appended claims, in which it is` my inten` tion to claim all novelty inherent in my invention as broadly as-permissible, in view of the prior art. I claim as my invention: 1. Apparatus for withdrawing a mold from a mold form, which apparatusfcomprises means for holding the mold form, a plate having a plurality of closely spaced projections distributed over its surface and engageable with a surface of the mold, sealing means encircling said plate and adapted to seat tightly against such mold surface, means for exhausting gas from the spaces on the mold-engaging surface of said plate between said projections, whereby, a partial vacuum will be formed over the plate engaged surfaceof the mold and the mold will adhere to said plate and will be pressed against and be supported by said projections against distortion or disrupltion by pressure on the side of the mold opposite said plate and means for separating said plate and said mold form.

2. Apparatus for withdrawing a mold from a mold form, which comprises means for supporting the mold form, a plate having a plurality of upstanding projections and interposed grooves, said projections being engageable with a surface of the mold, means carried by said plate for forming an air tight seal with the engaged mold Isurface around the grooved portion of Ythe plate,

means for exhausting gas from said grooves to partially evacuate them, whereby the mold will adhere to said plate when said plate and said mold form are displaced relative to each other, and means for relatively separating said grooved plate and the mold form.

3. Apparatus for withdrawing a mold from a mold form which comprises means for supporting the mold form with an exposed mold surface facing downward, means for producing differential fluid pressures on opposite surfaces of the mold, the higher pressure being on the upper mold surface, whereby the mold and mold form maybe separated, and a ribbed member beneath said supporting means andV exposed mold surface and engageable with such exposed mold surface to support it against distortion and disruption by such differential pressures.

, 4. An apparatus for withdrawing almold from tially evacuating the space bounded by said rib between said surface of said plate and said surface of the mold, whereby the mold will adhere to said plate when it and the moldform are displaced relative to each other, and means for relatively separating said plate and lthe mold form.

` 5. An apparatus for withdrawing a soft mold from a mold form, which comprises means for supporting the mold form, a plate having an endless, rigid rib integral with andvupstanding from the surface thereof adapted to penetrate a surface of the soft mold sumciently to effect a continuous sealing engagement therewith, means for partiallyevacuatlng the space bounded by said rib between said surface of said plate and said surface of the mold, whereby the mold will adhere to said plate when it and the mold form are displaced relative to each other and means for relatively separating saidplate and the mold form'.

6. An apparatus for withdrawing a mold-from a match plate and a flask, which apparatus comprises means for supporting the match plate and the flask, a second plate having a grooved surface bounded by a rib extending around said plate, said rib being adapted for sealing engagement with a surface of said mold, means for partially evacuating said grooves between said surface of said second plate and said surface of said mold, whereby said mold will adhere to `said second plate when said second plate and therebetween, said projections including a sealing rib engageable in air-tight contact with portions of the mold back completely surrounding a depressi-on, and means for exhausting gas from such sealed depression while the mold back'is engaged by said projections, for creating a partial vacuum within such sealed depression.

8. Apparatus for engaging the back of a mold, I

comprising a plate having on one side thereof a plurality f substantially parallel integral ribs with grooves interposed therebetween, each marginal rib being adapted for sealing engagement with the mold back, sealing means engageable with the mold back for sealing the groove ends, and means for exhausting .gas from the grooves,

for creating a partial vacuum therein when said Y ribs and said sealing means are engaged with the.

9. Apparatusfor withdrawing a mold from a mold form' including a patern, which comprises means having a plurality ofclosely spaced prolections distributed over its surface-and engage-v able with that face of the mold opposite the pattern, and means to act upon the face of the mold with which said nrst means is engageableV for producing a lower fluid pressure on such mold face than on the mold face engaged by :the pattern, said nrst means operating to support the mold against distortion and disruption when the mold is subjected'to such differential iiuid presl0. The method of making a mold .for casting purposes by the use of a container composed of a match plate having a pattern thereon and an open topped ask rim upstanding from such match plate and surrounding the pattern, which comprises lling such container with molding material to-a level below the upper edge of the flask rim,' and then, while holding the match plate and ask rim against movement relative to each other, simultaneously withdrawing the mold from contiguous `engagement with the match plate 'and pattern and shearing its sides from the askrim.

11. The method of withdrawing a soft mold for casting purposes from a mold form including a match-plate having a pattern thereon, which comprises holding the mold form'. subjecting the mold to differential uld pressures on opposite sides thereof, thereby displacing the mold relative to the mold yi'orm away from the molds higher pressure side and withdrawing the pattern from the mold, and, during subjectionof the mold to such differential fluid pressures. sup4 porting the side thereof exposed to the lower pressure by engagement sufllciently distributed over such side to prevent buckling of the mold and appreciable displacement of the soft mold material. v

y 12. 'I'he method of withdrawing a soft mold for casting purposes from a mold form including a match plate having a pattern thereon, which comprises holding the mold form, grippingthe soft mold by creation of a partial vacuum on that face thereof opposite the pattern, engaging closely spaced areas |oi the mold face thus gripped distributed over substantially'the entire region of vacuum application, thereby supporting the soft mold against buckling and displacement of mold material therefrom, and, while thus holding the mold form and gripping the mold, separating the mold from contiguous en- 13. The method of withdrawing a soft mold for f casting purposes from a mold form including a match plate having a pattern thereon, which comprises holding the mold form, gripping the soft mold by creation of a partial vacuum on that face thereof opposite the pattern. engaging the mold face thus gripped throughoutvthe lengths of closely spaced parallel lines distributed over substantially the entire region of vaccum application, thereby supporting the soft mold against buckling and displacement of mold material therefrom, and while thus holding the mold form and gripping the mold, separating the mold from contiguous engagement with the mold form and thereby withdrawing the pattern from the mold. 14. The method of withdrawing a-soft mold for casting purposes from a mold form including a match plate having a pattern thereon, which comprises holding the mold form, engaging with closely spaced projections that face of the soft mold opposite the match plate and pattern, subjecting the mold to diiierential fluid pressures on opposite sides thereof, the higher pressure being exerted against the match plate and pattern engaged face of the mold, thereby forcing the mold material against and somewhat around the projections, displacing the mold relative to the mold form and thereby withdrawing the pattern from the mold, and thereafter subjecting such opposite sides of the mold to reverse differential pressure, thereby forcing the soft mold material away from the projections.

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