US2680889A

US2680889A - Core blowing apparatus

Info

Publication number: US2680889A
Application number: US281371A
Authority: US
Inventors: Heinrich J B Herbruggen
Original assignee: FED FOUNDRY SUPPLY CO
Current assignee: FED FOUNDRY SUPPLY CO; FEDERAL FOUNDRY SUPPLY CO
Priority date: 1952-04-09
Filing date: 1952-04-09
Publication date: 1954-06-15
Anticipated expiration: 1971-06-15

Description

June l5; 1954l Filed April 9, 1952 H. J. B. HERBRUGGEN CORE BLOWING APPARATUS 2 Sheets-Sheet l Z D3 20 7 I 240 V 4 /5 210 f 7 27./ /a

INVENTOR.

Affari/yf June 15, 1954 H. J. B. HERBRUGGEN 2,680,889

CORE BLOWING APPARATUS Filed April 9, 1952 2 Sheets-Sheet 2 5 Zoo' ZZS rrop/vsys,

Patented June 15, 1954 CORE BLOWING APPARATUS Heinrich J. B. Herbruggen, Cleveland, Ohio, as-

signor to 'The Federal Foundry Supply Co., Cleveland, Ohio, a corporation of Ohio Application April 9, 1952, Serial No. 281,371

16 claims. l

This invention relates to a system and apparatus for blowing cores and molds and, more particularly, is concerned with a core blowing apparatus having a controlled fluid pressure operating system.

Basically, the core blowing apparatus of the type under consideration embodies a sand transfer chamber supported in operative relation to a core or mold box which may be positioned in core blowing relation to the sand chamber by means of a clamp or lift arrangement. The positioning and blowing operations may be lcontrolled individually or automatically in successive related stages. Among the difficulties attending such operations is the proper sequential control of such related successive operations. improper sequential control of the operations or inadequate safeguards against individual functional operation of some apparatus component which is unrelated to the overall core blowing operation present a number of diflicult problems.

By way of example, the usual sequence of operations contemplates that the core or mold box be securely and properly in position before the core blowing operation takes place. Likewise, optimum operation requires that the sand chamber be exhausted after the blowing operation is completed sufciently to prevent the escape of sand under pressure into the surrounding environment should the core or mold box `be removed from operative position. Such impro-per operating sequence may create unfavorable working conditions and endanger the operation, as well as decrease the output of the apparatus and increase wear and tear to such an extent as to offset reasonable maintenance.

Accordingly, it is an object of this invention to provide a core blowing apparatus having a controlled iiuid pressure operating system which will automatically insure proper sequential operation of the respective ycore blowing functions of the apparatus.

Another object of the invention relates to the utilization of the frame and supporting members as fluid pressure conduits in the operating system.

Briefly, in accordance with this invention there is provided a core blowing apparatus including a sand transfer chamber which has provision for the admission and discharge of air and sand and, also including a fluid pressure operated removable cover cooperating as a gate between the chamber and a sa-nd storage hopper. The sand transfer chamber is operatively supported relative to a movable core or mold box `support that is positioned into operative core blowing relation by means of a uid pressure controlled lift mechanism while the supporting frame and intermediate supporting structures are utilized advantageously as fluid pressure conduits in the operating system.

The invention further embodies a common fluid pressure operating system for positioning the cover in operative relation over the sand chamber which positioning automatically applies operating pressures to pneumatic controls for the lift mechanism and for the admission of air to the sand transfer chamber. The pneumatic controls automatically delay the ladmission of the operating pressure within the chamber until after the lift mechanism has initially moved the core box or mold into core blowing relation with respect to the chamber and, after the core blowing operation is completed, automatically delays the return or release of the lift mechanism to separate the core box or mold from the blow chamber until and in response to a predetermined reduction of the operating pressure within the sand transfer chamber. The system also automatically provides for the removal of the cover into sand charging position in response to a predetermined reduction of fluid operating pressure within the lift mechanism, thereby insuring that the cover is not removed from the chamber until after the lift mechanism has been released.

In the drawings,

Fig. 1 is a vertical View of the core blowing apparatus structure illustrating in partial crossv section the interior construction of the principal operating members;

Fig. 2 is a horizontal view taken along the lines 2.-2 in Fig. l, illustrating in plan view one of the pneumatically positioned core or mold box supporting arms;

Fig. 3 is a schematic illustration of a portion of the operating system connected in plan view with the cover operating mechanism as shown at A-A, which is a partial view of the apparatus taken along the lines A-A in Fig. 1, and with the sand transfer chamber as shown at B-l which is a partial view of the apparatus taken along the lines B-B in Fig. l of the drawings; and,

Fig. 4 is a diagrammatic illustration of a combined pneumatic and hydraulic operating system for the apparatus of Fig. 1 rschematically illustrating only the basic operating members essential to such operation.

Referring now to the preferred embodiment in Yedge of the baille 5 i es L? Fig. 1 of the drawings, there is shown a rigid frame for supporting the operating members of the core blowing apparatus of this invention which frame embodies a pair of spaced vertical pillars l and I l, each of which are hollow tubular like members adapted to serve as conduits in the operating system as will be hereinafter more fully described. Each of the pillars are supported by base members i2 and i3 and are rigidly secured together at the top by a cross member i4. The cross member iii has suitable spaced coupling members i5 and I, each of which are hollow so as to provide communicating reservoirs between each of the hollow pillars i and l i and the corresponding connecting conduits 2t'l and 91 to the operating system respectively. Connecting rods Il and i8 extend through the corresponding coupling members and pillars and are each provided at the top end with nuts i9 and 20, which threadingly engage the top end of the corresponding connectingr rod, and at the bottom end Vwith nuts 2i and 22, which engage corresponding bearing surfaces 23 and 2t on the base members I2 and i3. Thus, when the respective nuts at the ends of the connecting rods are tight, the entire structure is made rigidly secure to provide a rigid rectangular frame for the operating ele- .ments or members of the core blowing appa- 4ratus.

The cross member Ill carries a sand hopper 3i) which communicates through the cross member to feed sand into a sand transfer chamber i! operatively disposed therebelow. The sand transfer chamber 5G is in the form of a hollow cylindrical member open at the top and having .an annular baille 5i. of lesser diameter, concentrically mounted therein. The transfer chamber is provided with a removable base in the form of a blow-plate 52 having a central core blowing opening 53 which is adapted to communicate with a core or mold box cavity that may be operatively ysupported therebelow. The removable blow plate 52 may be coupled to the cylindrical chamber 5t through an externally accessible coupling spider 54. 1The baiile 5i forms a sand chamber 55 within the transfer chamber and the space between the baille and the external cylindrical wall of the transfer chamber provides an air space about the sand chamber by means of which air under pressure may be admitted through a plurality of openings in the bafiie bi to the sand chamber 55.

The sand chamber 55 is provided with an agitating member 5S having annular spaced stirring elements 59 which are secured to a ring gear 60 operatively positioned in bearings within the air space in the chamber for rotation along the top A pinion i5 l shown in dotted lines in Fig. l, coacts with the ring gear 6G within the air space to drive the ring gear and rotate the stirring elements 59. The pinion 5i may be carried on a shaft 62 extending through the external cylindrical wall of the transfer chamber 50 and in turn coupled to a source of driving V(power such as a motor 65.

Referring now to Fig. 3 of the drawings, and particularly to the portion designated B-B therein, the sand transfer chamber 50 is shown supported from the pillar lil by hollow arms 'l0 and 'H which extend from opposite sides of the cylindrical chamber wall towards the pillar I0. The extended ends of the supporting arms are pivotally coupled to a rotatable sleeve 'M on the pillar lil through a hollow horizontal shaft which communicates interiorly with the hollow interior of the respective supporting arms l0 and 1|. The ends of the supporting arms adjacent the transfer chamber 50 are likewise coupled through another hollow horizontal shaft 'IS with the air space in the transfer chamber 50. The hollow shaft 'i5 also communicates intermediate its ends through a pneumatically controlled valve with the hollow interior of the pillar lo, thereby providing continuous valve-controlled communication from the interior of the pillar i0, through the hollow shaft (T5), thence through the supporting arms 'IB and li and the hollow shaft 1S to the air space of the transfer chamber 50, as will be hereinafter more fully described in connection with Fig. 'i Vof the drawings.

The apparatus is intended to blow either cores or moles and is provided with a pair of supports and 8| therefor which enables a high number of blowing operations per working hour. The core or mold supports 80 and iii are each mounted for pivotal movement about a corresponding supportingpillar of the apparatus frame, as shown in Figs. l and 2 of the drawings, Each supporting arm has an opening 82 therethrough with an inwardly turned lower flange 83 upon which a pattern plate 34 may be supported. The size of the opening through the arm is such that a flask or core box 86 may be supported on its upper edge. The flask or core box is preferably provided with an inwardly turned lower flange S5 which partially extends transversely into the opening t2 for engagement by the marginal edges of the pattern plate or by a hydraulic lift platen, as will be hereinafter more fully described.-

The frame carries a self-contained pneumatically-controlled hydraulic lift mechanism which includes a hydraulic fluid piston-chamber supported on a cross member 9! rigidly extending between the base members l2 and i3 of the frame. The hydraulic fluid chamber SG is provided with an intermediate baille 92 for supporting a lift piston rod 93' which carries an operating lift piston S4 within the chamber 9B in the area above the baffle `92 and a lifting platen 95 at the end external to the chamber 9%). A 'conduit 96 communicates between the portion of the fluid chamber SB above the baille 92 and the hollow interior of the pillar i i to convey hydraulic fluid through the pillar Il into the chamber 9b, whereby displacement of the fluid within the pillar ii and chamber 98 will move the operating piston M and the lift platen to position the flask or core box 86 in operative core blowing engagement with the blow plate 52 of the transfer chamber 5i). It is of course understood that any type of fluid pressure may be utilized to provide the necessary lift action.

The pillar H is connected at the top through the coupling member IE to a conduit 9? which is in turn connected to a compound hydraulic valve mechanismV comprising a casing 209 having a ball check valve ZES and a differential slide valve 212 which open separate hydraulic fluid paths through the casing 209 to a hydraulic fluid reservoir 2 I0 depending upon whether pneumatic operating pressure is applied to or released from the surface of the hydraulic fluid within the reservoir 2li), as will be hereinafter more fully described in connection with Fig. 4 of the drawings. The application of pneumatic pressure to the hydraulic uid within the reservoir 2 it will cause a displacement of fluid through the compound valve mechanism in a direction to move the operating piston 94 upwardly and thereby lift the platen 95 and the flask or core box 855 into operative engagement with the blow plate 52.

y assenso Further displacement moves -thefentire assembly .of the platen 95, flask orcore box .06, and transfer chamber 50,`into operative .core-blowing engagement with a cover |22,as will be lhereinafter.more fully described.

Referring again .to Fig. 3, Where like numerals designate like parts, there .is schematically illus- .trated a portion of the operating system rcon-` supportingarms 1.0 and 1| to "a source of pneu# matic pressure -200 (Fig. 4) which is in turn connected to the pillar I through coupling member and conduit 201 consists of a valve body which has an overhanginer head |0| on the pillar side of the port |013 with a shank por-tion |02 that.ex'

tends for a small distance parallelvto the sides-of the .port and then is bei/'felled inwardly toward .the valve rod I 03 which thre-adedly engages the shank |02 of the Valve body at one end and extends at the other end into a'chambered extension of the hollow shaft 15. The :chambered extensionof this hollow shaft forms a chamber |05 which carries a T-shapedy piston I 06 which is supported at the extended end of the valve rod |03 so that the piston |06, rod |03,.andvalve |00.. move axially as a unit. Such movement is limited in one direction by interlocking engagement between the underside of the head 1|01 of the T-shaped piston |06 and the inturned marginal edges .|08. of the piston chamber |05.

The piston chamber |05 isprovidedwith a further extension I l0 which .has a pneumatic. pressure inlet l adapted izo-receive apin H2 that is lxedly carried by the headv |01 ofthe T-shaped piston |00. A sinuous opening `H3 is formed in the chamber extension ||0 to connect` the inlet with the piston chamber |05. This sinuous opening I3 is normally blocked from the inlet when the T-shaped pistoni is in a position to close the Valve |00. Y

A hleeder opening ||4,. `of much smal-ler .cross section than the sinuous opening ||3 .communicates separately and .distinctly from the -inletsIH f with the piston chamber 1| 05.,.so that 1when pneumatic operating pressure is .admitted to the. .inlet from a connecting conduit 490,. Vit passes through the bleeder opening H4 to the. piston chamber |05 and slowly moves the 'I1-shaped piston .|06 in a direction to open the valve 4.00.

The, bleeder H4 and sinuous opening H 3 provide a compound, successively `acting inletforfadmitting pneumatic operating pressure Itothe piston chamber 05 which results in a delayed'. opening of .the valve |00. The distancefthat thepiston- |06 and its pin I2 must move beforetopen-ingthe sinuous opening H3 `to communicationwith the inlet III is equivale-nt to the axialtlength of. the shank portion |02 of the valve '|00so .that the valve |00 does not establish communicationpba tween the hollow shaft 15fand theA pillar.i|0 until the T-shaped piston |06 has .moved a suicient distance to open .communication between the rinlet and the sinuous opening U3. Then-. since the sinuous opening H3 is` of larger cross:` section than the bleeder opening l |4, the rataofopening. movement of the valve |00. will consequently'increase to .open communication ybetwern the hollow shaft 15 and the pneumatic operating. pressure within the-pillar# 0. This construction enables a delayed-.opening of .the valve |00 after vapplication of .pneumatic operating `pressure to theinlet for a length of time sufficient to allow `the hydraulic lift mechanism to operate to move the core or .mold box into operative core blowing engagement with the transfer chamber 50,5thereby preventing vadmission of core blowing pneumatic pressure within the transfer chamber 50 before the vapparatus isreac'ly, as will be hereinafter more fully described in connection with theoperating system schematically illustrated in'Fig. 4 of the drawings.

Referring again :to Fig. 3 `of the drawings there is also schematicallyl illustrated a .portion of the operating system connected in plan View at A`A with the top of the frame andthe combined `gate and cover assembly |20 and .associated .operating mechanism. The combined gate and cover assembly |20 is in the form of a sector of a. circle lhai/ing .a circular gate opening |21 angularly spaced from a depending circular annular flange |22 yforming a cover. 123 andair exhaust chamber for the transfer chamber 50. The combined'gate and cover assembly |20 is pivoted at itsapex to a horizontal extension |25 from the cross member 4 so that either the opening |f2| or the cover portion |23 may be alternately positioned coincident with the opening in the sand transfer chamber 50. f

The hopper is carried by 'thefcross member .I4 in axial vertical alignment with the transfer chamber so that when :the combined gate `and cover assembly |20 :is positionedwith the opening |2| coincident therewith, the .sand will be guided into the transfer chamber :50 and, when the combined gate and cover assembly '|20 is positioned so that the depending annular flanged closedportion |22 surmounts thev'opening in lthe transfer chamber 50, it acts Aas a closure for the hopper '30 aswell as a cover |23 for thetransfer chamber 50. A floating annular ring |26 loosely surrounds Vthe discharge end of thehopper 30 sothat it rests on the combined gate and cover'assemb'ly |20 and acts as a scraper vacross the: gate opening |.2.| during closing movement ofthe .cover portion |23.

The cross member Itis provided with another horizontal extensionlz which pivotally supports a pistonchamber 'H0-with a piston 1| 3| `movably supported therein. A piston rod |32 extends outwardly yfrom. the chamber |30; towards pivotal engagement with vthe combined 'gate and cover assembly |20and the piston |3| is pneumatically operated for reciproeation` within the chamber |30 to move the combined gatezand coverv assembly |20 into open and closed 'position relative to the transfer chamber 1,50.

I As previously indicated, the depending 'annular flanged portion |22 ofthe cover acts as an air exhaust chamber .for the transfer chamber 50 and has a valve controlled exhaust port |40. A suitable screen and ilter |45 is supported within the annular depending 'angeportion'i22 to prevent sand from the transfer .chamber '50 from exhausting through the cover and port |40? tothe atmosphere.

Fig. 3 of the Vdrawings also illustrates at A-A the .mechanically 'positionedv slide'valve `I 50 which may be positioned to `establish communication be- Y tween -afpneumatic pressure inlet conduit 5I and a connecting yconduit A| which: is in turn connected '.toother pneumatically operated pistons, as will .be hereinafter` more fully describedl in connection with Fig. d ofthe drawings. .A valve casing |52 for the slideva-lve |50 :maybe sup.-

ported as shown on the cross member I4 or on the pillar I0. The slide-valve |50 is in the form of a piston having a piston rod |53 extending externally towards the movable combined gate and `cover assembly 20 so that whenever the assembly |20 is positioned by the pneumatically controlled piston i3! to close the transfer chamber 50, the adjacent end of the assembly engages the piston rod |53 to shift the piston |50 and to open communication between pneumatic pressure inlet |5I and the connecting conduit |55.

The conduit |55, on the other side of the slide valve casing |52 has a branch |80 communicating with a spring-pressed transfer chamber exhaust controlling piston MI and another branch |90 communicating with the inlet II I of the pneumatically controlled valve |00 of the transfer chamber 50. Thus, when the gate and cover assembly is positioned to close the transfer chamber 50, the slide valve |50 is mechanically positioned to apply the source pressure to close the exhaust port |40 and to initiate the opening movement of the valve |00.

The conduit |80 has another branch |95 which applies the pneumatic air pressure from the slide valve casing |52 to the operating piston of a spring-pressed slide valve 20|, which controls the admission of pneumatic pressure from the source 200 through the conduit 203 and connecting conduit 204 to the hydraulic uid reservoir 2|0. The slide valve 20| also isolates the casing 202 from communication with the atmospheric release valve casing 220, as will be hereinafter more fully described. Thus, consequent upon the mechanical positioning of slide valve |50 to apply pneumatic pressure to the conduit |55,

there is a simultaneous application of pneumatic pressure to the transfer chamber exhaust piston IM, to the inlet |I|, and to the operating piston of the slide valve 20|;

When the slide valve 20| is pneumatically positioned to admit air pressure from the source 200 to the hydraulic fluid reservoir 2|0, a branch conduit 2I| applies this pressure to the large area side of another spring-pressed slide valve 2|2 which, due to the dissimilar areas of the valve body ends, closes the return hydraulic path from the pillar to the' reservoir 2|0. yAt the same time, the pneumatic pressure in the reservoir 2|0 acting on the surface of the incompressible hydraulic luid displaces such fluid through the ball 'check valve 2I3, the pillar II, and the piston chamber 00 to move the operating piston 94 and lift platen 95 to position the core box or flask 06 into operative engagement against the blow plate 52. Further displacement of hydraulic fluid in this direction moves the entire assembly of the iiask or core box and the transfer chamber 50 into operative engagement with the cover |23. Since the slide valve ZIE maintains'the return path for the hydraulic fluid closed under the action of pneumatic pressure from conduit 2|I and the ball check valve 2|3 acts as a stop to prevent a reverse displacement of hydraulic uid through its path, the operative members of the apparatus will remain in clamped engagement until the pneumatic operating pressure is released. v

As previously described, the mechanical positioning of the slide valve |50 applied pneumatic pressure to the inlet at the same time as it was applied to the operating piston of the springpressed slide valve 20|. The distance that the T-shaped piston |00 Vmust move under bleeder pressure from the bleeder opening ||0 before full pneumatic pressure is applied from the sinuous opening ||3 is such that the valve |00 will not open until the core box or flask 85 and transfer chamber 50 have been securely clamped together with the cover |23 in operative core blowing position. Thus, the delayed application of pneumatic pressure from the pillar |0 to the transfer chamber 50 insures that no sand will be forced into the surrounding environment to the detriment of the operator and apparatus and, after the valve |00 has opened, the pneumatic pressure enters the transfer chamber 50 through the hollow supporting'arms l0 and 1| and passes through the openings in the bailie 5|, thence through the blow opening 53 and into the flask or core box 80. During the blowing operation, the stirring elements 5S are rotated by the motor 05`and a uniform transfer of sand is effected from the transfer' chamberl 50 into the flask or core box. f

At the same time as pneumatic pressure is admitted to the transfer chamber 50 from the pillar I0, pneumatic operating pressure is also admitted to the conduit 2|5 through the hollow shaft 15 and is applied to the casing 220 of a differential slide valve 22| at the large area end of the valve. The reduced area side of the differential valve 22| is coupled through a conduit 222 to the slide valve casing 202 and, since at this stage of the operation the slide valve 20| is po-` sitioned under pneumatic pressure to isolate the casing 202 from the casing 220, the only pneumatic pressure acting on'the slide valve 22| is at the enlarged endand it moves the slide valve 22| to a position to close an atmospheric vent 223 in the casing 220.

After the core blowing operation is completed, the toggle slide valve ISI is' hand positioned to isolate the connecting conduit |65 from the source 200 and to connect it to an atmospheric vent |62 in the valve casing |60, thereby releasing to atmosphere the pneumatic operating pressure from the branch conduits It and |61 throughthe connecting conduit I'B and also from the branch conduits |55, |39; |90 and |95 through the one way check valve 230 and the connecting conduit |65. This release removes pneumatic operating pressure from the springpressed exhaust piston IM which opens the transfer chamber 50 to the atmosphere through the exhaust port |40 and also removes pneumatic operating pressure from the inlet allowing the pneumatic pressure in the pillar Iii, acting against the valve |00, to close that valve and isolate the transfer chamber 5G from the source of pneumatic operating pressure 200. Likewise, the release of the pneumatic operating pressure from the branch conduit |95 through the check valve 23!) allows the spring-pressed slid-e valve 20| to isolate the hydraulic fluid reservoir 2li) from the source iiiandV also to establish com- 1 munication from the reservoir 2|@ through the casing 232 to the atmospheric release valve casing 220. However, since the opposite end of the slide valve 22| is of larger area, the slide valve 22| the release of pneumatic pressure from the reservoir 2| t through the atmospheric vent 223. Thus, the hydraulic iluid in the reservoir 2in remains under pneumatic operating pressure and maintains all of the operating members of the apparatus in secure clamped core. blowing relation.

In the meantime, pneumaticpressure has been exhausting through the. port |40 from the` transferchamber 50 and has consequently been reducing the pneumatic operating pressure in the conduit 2|5. For illustrative purposes, if the ratio of areas of the slide valve. member 22| were 4 to l, the slide Valve 22| would not move-to uncover the atmospheric vent 223 until the pneumaticl pressure in the transfer chamber 50v and the `conduit 2|5 were reduced to one-quarter of that acting at the other end of the slideA valve 22|y which latter is substantially they entire operating pneumatic pressure within the reservoir 2m. Thus, it is readily seen that by suitable choice of differential areas forzthe valve member 22|, the pneumatic operating pressure' will: not be released from the hydraulic lift mechanismr until after the pneumatic pressure within the transfer chamber 50 has been reduced toa predetermined safe amount so as not to be sulficiently strongto force sand out of the chamber'-v into the surrounding environment.

After the atmospheric vent 223 has been opened: in. response to thev predeterminedy reduction of pneumatic pressure within the transfer chamber. 50., the hydraulic lift mechanism'will still notA release the operating members until. the pneumatic pressure within the reservoir 2||l` and: the conduit 2|| is reduced a predeterm-ined amountdepending upon the ratio. betweenthe differ-- ential end areas of the slide valve 2|-2 which, again for exemplary purposes of illustration, may be in the ratio of 4 to 1, resulting in` an opening of they return hydraulic path when the pneumatic pressure in the reservoir 2 I0 and branchconduit 2:|| has been reduced to one-quarter.v ofthat ofthe source; The release of the slideyvalve 2 |=2-. tof open the return path for theV hydraulicfluid:v

remains stationary and continues to block l@ allows a return displacement of hydraulic fluid acting under the weight of the operating members through the operating lift piston 9d.

The release of the pneumatic pressure from the branch conduit ist allows the spring-pressed slideval've lll' to isolate the conduit 375 from the source 26s and4 connects it through the casing- |l2 to the atmospheric release valvey casing 25d'. The valve casing Edt and slide valve 24| therein are similar tothe casing 22@ and slide valve 22|' and the enlarged end portion of the casing 2li@ is connected through the conduit 222 and valve 2&2 to the branch conduit 204, which at this stage of the operation is inY communication with the hydraulic reservoir 2|0. The ysmal-ler end area of the Valve casing 24'0 is in communication with the piston chamber |3 on the enlarged side of the piston 3| through the Valve casing |72. and conduit |75. However, due to thediiferential end areas of the slide -Valve member 2M, the valve member till will be `positioned withinthe casing 240 to isolate casing Beil. from the atmosphere Vent 243, therebyipreventing the release of the pneumatic operating pressure from the chamber |36). The valvemember 2M operates similarly to the slide valve 22| and will not move to open the casing. 240 tothe atmosphere until the pneumatic pressure in line 222 is reduced a predetermined. amount, which in accordance with the foregoing illustrative examples, may be when such pressure. is reduced to one-quarter of that of the source-,

`it is readily apparent that the pneumatic pressure in liney 222, is substantially the same pneumatic pressure that exists within* the hydraulic reservoir 2li) and branch conduit 2H.. Thus, the pneumatic pressure in the piston chamber E30 will not be released to amosphere until the. hydraulic lift has been released and at that time the pneumatic pressure. from the source acts through theconduit branch Ill' against the smaller area end of the piston ISI to openv the cover |23 and position the opening 2| under the hopper for a re-charge of sand, thereby in- Y suring that the combined gate and cover assembly |20 is not positioned for re-charging` of the transfer chamber 56 until the hydraulic. lift mechanism. has completely released the operating members of the apparatus and returned. them to re-charging position for a new coreV blowing.

cycle.

Thus, the core blowing apparatus and oper-` ating system of this invention automatically insures proper sequential operation of the re- .K spective core blowing functions Vof each component of the apparatus so as to safeguard the operator and maintain favorable working conditions with a yminimum of maintenance and' an. optimum production. The apparatus and' system also efficiently utilizes lthe structural components to their maximum extent wherever' possible by combining their functions operatively' inthe structural f' positioning and Ysupport of the components andV in the functions of the op-Y erating system.

I have shown and describedv what I consider tol be the preferred embodiments of my invention along with similar modified forms and; suggestionsv and, it willr be obvious to thoseL skilled in7 the art. that other changes andV modications'ma'y be made without departing from the scope of my invention as described by the appended claims.

. I claim-1 1. vIn a core.blowing..apparatusadaptedior.op-

eration from a source of fluid pressure and provided with a movable core box operatively supported below a sand transfer chamber having a sand discharge opening adjacent the core box and open at the other end to receive sand therein, a uicl pressure operated lift for moving said core box into operative engagement with the transfer chamber, a removable cover for said transfer chamber, valve means adapted to be positioned by said cover in the closed position to automatically apply operating iiuid pressure from the source to said lift and to said 'transfer chamber, and fluid pressure controlled valve means adapted to be positioned by the applied pressure for coaction in said transfer chamber to delay admission of liuid pressure thereto until after said lift has moved the core box into operative engagement with said transfer chamber.

2. In a core blowing apparatus provided with a sand transfer chamber having a sand receiving opening and a sand discharge opening and surmounting a movable core box, a fluid pressure controlled lift for moving said core box into operative core blowing engagement with the discharge opening of said sand transfer chamber, said sand transfer chamber having a fluid pressure controlled inlet for admitting fluid pressure therein, a removable cover for the sand receiving opening of said transfer chamber, said cover being provided with a fluid pressure controlled exhaust for said transfer chamber, fluid pressure controlled means supported adjacent said cover and adapted to be positioned by said cover in the closed position to automatically apply fluid operating pressure to operate said lift, to open said chamber inlet, and to close said fluid pressure controlled chamber exhaust, valve means within said chamber inlet for delaying the admission of fluid pressure therethrough until after y,

said lift has moved the core box into operative engagement with the discharge end of said transfer chamber, means for opening said iiuid pressure controlled chamber exhaust after the core blowing operation is completed, and a second uid pressure controlled means for automatically releasing the operating pressure from said lift in response to a predetermined reduction of fluid pressure within said transfer chamber.

V, 3. In a Ycore blowing apparatus provided with a sand transfer chamber having a sand receiving opening and a sand discharge opening and surmounting a movable core box, a fluid pressure controlled lift for moving said core box into operative core blowing engagement with the discharge opening in said sand transfer chamber, saidsand .transfer chamber having a valve controlled inlet for admitting iluid operating pressure therein and a controlled exhaust therefor, a fluid pressure operated removable cover for the sand receiving opening, means for applying fluid operating pressure to open and close. said cover, valve means adapted to berpositioned by said cover in the closed position to apply fluid operating pressure to operate said lift, to open said chamber inlet and to close said chamber exhaust, said valve controlled chamber inlet including means for delayingthe admission of fiuid'pressure therethrough until after said' lift has moved the core box into operative engagement with said chamber, means for opening Vsaid chamber exhaust after' the core`blowing operation is complete, fluid pressure controlled means fofautomatically releasing the operating pressure from thelift in response lto a predetermined reduction of fluid pressure within the sand transfer chamber, whereby said core box is separated from operative engagement with the chamber, and a second fluid pressure controlled means for automatically reversing the fluid operating pressure acting on the cover to move the cover to open position in response to a predetermined reduction of lluid operating pressure in the lift.

4. In a core blowing apparatus adapted for operation from a source of fluid pressure and having a sand transfer chamber and a movable core box operatively supported relative thereto, a fluid pressure controlled lift adapted to be coupled to the source to move said core box into core blowing engagement with said sand transfer chamber, valve means for successively applying fluid operating pressure from the source to said lift and to said sand transfer chamber, means for exhausting said sand transfer chamber after the core blowing operation is completed, and a fluid pressure controlled valve coacting therewith to automatically release the operating lluid pressure from said lift in response to a predetermined reduction in the iluid pressure within said sand transfer chamber.

5. In a core blowing apparatus adapted for operation from a fluid pressure source and having a sand transfer chamber and a movable core box operatively supported relative thereto, a fluid pressure controlled lift adapted to be coupled to the source to move the core box into operative core blowing engagement with the sand transfer chamber, a iiuid pressure operated removable cover for said sand transfer chamber, fluid pressure controlled means adapted to be coupled to the source to successively apply iluid operating pressure to close the cover, to operate the lift, and to admit fluid pressure to said chamber, means for exhausting said sand transfer chamber after the `core blowing'op'eration is completed, fluid pressure controlled means coacting therewith in response to a predetermined reduction of pressure in the chamber for removing the fluid operating pressure from said lift, and other fluid pressure controlled means for reversing the fluid operating pressure to open said cover in response to a predeterminedreduction of the fluid operating pressure acting on saidlift.

6. In a core blowing apparatus adapted for operation from a source of uid pressure and having a sand transfer chamber with a sand receiving opening and a sand discharge opening operatively supported relative to a movable core box, a fluid pressure controlled lift adapted to be coupled to the source to move said core box into operative core-blowing engagement with said sand discharge opening, a fluid pressure operated removable cover for said sand receiving opening,

means for successively applying fluid operating'- pressure from the source toV close said cover, to' operatesaid lift, and to` admit fluid pressure tosaid'transfer chamber, other means for exhaust-A ing said transfer chamber afterthe core blowing operation is completed, and iluid pressure controlled means coacting therewith tosuccessively release the operating pressure from said lift and fromsaid removable coverY in respcnseftora predetermined reduction of fluid pressure in said transfer chamber.,

7. Ina coreblowingvapparatus adaptedfor'op-l eration from a liuid pressure source andhaving a sand Vtransfer chamber witlrasa'ndv receiving' opening anda sand discharge opening, aV sandV storage hopper 'operativelyf'supported adjacent saidsand receiving opening, a combined cham-'-l ber cover and hoppery gate member movably supportedy intermediate said hopper and said chamber, a first fiuid pressure controlled means adapted to be coupled to the source to move said combined ygate and cover member to open or close said sand receiving opening, means responsive to the closure of said combined cover and gate member to apply fluid pressure from the source automatically to said chamber, other means for exhausting said chamber, anda second fluid pressure controlled means coacting therewith in response to a predetermined reduction of iluid pressure in said chamber for releasing the iiuid operating pressure from said first fluid pressure controlled means to open said combined cover and gate member.

8. In a core blowingapparatus having a vertically disposed hollow support, a sand'transfer chamber, a hollow supporting arm for said sand transfer chamber and vertical hollow support, means coupling the extended end of said hollow supporting arm to said vertical hollow support, the hollow interior-oi said supporting arm communicating with the interior of the hollow support at the extended end and communicating at the other end through the corresponding side of the sand transfer chamber with the interior thereof, means for applying fluid operating pressure to said hoilow vertical support, and valve means normally iselating the interior of said vertical hollow support from vthe hollow interior of said supporting arm, whereby upon opening of said valve, fluid operating pressure from the hollow vertical support is conveyed through the hollow supporting arm and into the interior of said sand transfer chamber.

9. In a core blowing apparatus having a source of duid pressure and a sand transfer chamber,

first conduit connecting said chamber to said source, a valve member in said'conduit, a piston having a piston rod extending in opposite directions from each end thereof, said valve member being carried at the extended end of one of said rods, a first fiuid pressure inlet for said piston, a

second conduit connecting said source to said first I:

normally blocking inlet, said other piston rod said inlet for a predetermined axial rod distance, said valve member having means normally blocking said firstconduit until said other piston rod has .moved an axial distance sufficient to unblock said fist inlet, and a separate fluid pressure inlet of reduced size maintaining constant communication from said second conduit to said piston, whereby said piston initially moves slowly in a direction to unblock said first inlet and thereafter moves rapidly to move said valve member out of blocking position in said rst conduit to admit fluid pressure to said sand transfer chamber.

1G. In a core blowing apparatus adapted for operation from a fluid pressure source and having a sand transfer chamber and a movable core box operatively supported relative thereto, ud pressure controlled means for applying and releasing fluid pressure to and from said transfer chamber, a fluid pressure controlled lift adapted to be coupled to the source to move said core box into operative core blowing engagement with said sand transfer chamber, said lift including a uid chamber having a lift piston operatively disposed therein, a fluid reservoir, a conduit interconnecting said uid piston chamber with said reservoir, a second means for applying fluid pressure to said reservoir, compound valve means in said connecting conduit to permit displaceextending towards said mechanism ment of fluid in the pistonv lifting .direction and..

at the same time prevent displacenfient:` in the opposite direction, other uid pressure controlled means for releasing the fluid pressure from said fiuid reservoir in response to a predetermined reduction of. uid pressure in said transfer chamber, said other fluid pressure controlled `means including means for reversing the operation of said compound valve, whereby said valve permits displacement of fluid in the operating piston return direction, to lower the lift. piston and core box out of core blowing position.y

ll. A lift for a core blowing apparatusccmprising in combination, a piston chamber, a lift piston operatively disposed therein, a :duid reservoir, conduit means connecting said piston chamber with said reservoir, means for applying fluid pressure lto displace the iiuidfrom said reservoir` into said piston chamber, a compound valveA in said conduit means providing-a double path for' iiuiol therethrough, a ball check valve freely supported in a rst fluid path to4 permit fluid displacement therethrough in-a pis-ton lifting direction and to prevent displacement in the piston return direction, a diiferential slide valve in the second fluid path and having a small valve area at one end exposed to the fluid-pressure in said rst path, said slide valve having: a large vvalve area at the the iluid pressure pat to permit iiuid displacement in a return piston direction in reduction of duid pressure in said reservoir `in a ratio to said applied fluid pressure equivalent yto the ratio of the valve area. Y

l2. In a core blowing apparatus having a sandtransfer chamber and a movable core box operatively supported -relative thereto, a supportingn frame therefor comprising a pair of spaced hollow vertical members, a lift operatively supported by said members below said movable core box to move the core box into operative core blowing engagement with said sand transfer chamber,` a hollow arm communicating with said sand transfer chamber and supporting said spaced vertical relation above said movable core box from one of said hollow vertical supports, means for connecting said one i support with a source of iiuid pressure, a fluid pressure controlled valve for operatively connecting fiuid pressure from said one hollow vertical support through the interior of said hollow'arm to said sand transfer chamber, an exhaust for Y connecting a source off uid to said other hollow'vertical support, other, means connecting said other hollowvertical'sup-" said chamber, means for port with said lift mechanism, and iiuid pressure controlled means for displacing the fluid from said other hollow vertical support through said lift mechanism in a direction to move said core box into operative core blowing engagement with said sand transfer chamber, and other fluid pressure controlled means for automatically reversing said uid displacement in response to a predetermined reduction of iiuid pressure in the chamber to return the core box out of operative engagement with the chamber after the core blowing operation is completed.

13. In a core blowing apparatus provided with a sand transfer chamber having a iiuid pressure inlet and outlet and fluid means for positioning a member in operative core blowingrelation to said chamber, a fluid other end exposed-toin said reservoir, whereby said slide valve is moved to open said second huid.V

response to a predetermined small valve area toA the lar-ge chamber in Y hollow vertical pressure operating system therefor comprising. means for applying fluid operating pressure to said member positioning means and to said transfer chamber, a differential valve having a casing and a valve member freely supported therein, each end of said valve member having a different area, an inlet at each end of the casing communicating respectively with a different end of said valve member, an atmospheric vent through the casing adjacent the small end of said valve member and adapted to be covered and uncovered thereby, means connecting the casing in let adjacent the large valve member end to fluid pressure in said chamber, and other means connecting the casing inlet adjacent the small valve member end to the fluid operating pressure in the member positioning means, whereby the latter pressure is released through the atmospheric vent in response to a predetermined reduction in pressure in the chamber proportional to the ratio of the small end area to the large end area of said valve member.

14. In a core blowing apparatus provided with a sand transfer chamber having fluid pressure and sand inlets and outlets with a removable cover for the sand inlet having fluid pressure controlled positioning means and a movable core box having a fluid pressure controlled lift, a uid pressure operating rsystem therefor comprising, means for successively applyingiiuid operating pressure yto close the cover, to operate the lift, and to blow sand from the chamber into the core box, a pair of diiferential valves each having a casing with a valve member having dissimilar sized ends therein, each casing having an atmospheric vent adjacentrthe small end of the cor responding valve member, means exposing the large end of one valve member and the small end of the other valve member to the fluid operating pressure for said lift, other means exposing the small end of said one valve member to the fluid operating pressure in said cover positioning means and exposing the large end of said other valve member to the uid pressure in said chamber, and means for releasing the liuid pressure from said chamber, whereby the fluid operating pressure is first released from the lift through the vent in said other valve member casing in response to a predetermined reduction of pressure in the chamber and the fluid operating Apressure is next released from said cover lpositioning meansrthrough the vent in said one valve imember in response to a predetermined reduction of operating pressure from said lift, the predetermined reduction in each case being proportional tothe correspondingI ratios of the small end area to the large end area of the corresponding valve member.

15. In a core blowing apparatus adapted for operation from a source of fluid pressure and provided with a sand transfer chamber having a discharge opening surmounting a movable core box, a fluid pressure controlled lift for moving the core box into operative core blowing engagement with the discharge opening of the transfer chamber, a first fluid pressure controlled means adapted to be coupled to the source to successively apply operating pressure to the lift and to the transfer chamber a fluid pressure controlled atmospheric vent adapted to be opened consequent upon uncouplingof said means from the source to exhaust the transfer chamber after the core blowing operation is completed, and a second fluid pressure controlled means adapted to be positioned in response to a predetermined reduction of fluid pressure within the transfer chamber' to release the operating pressure from the lift.

16. In a core blowing apparatus adapted for operation from a source of fluid pressure and having a sand transfer chamber withV an open end and a discharge end and a movable core box operatively supported relative to the discharge end, a removable cover for the open end of the transfer chamber, a fluid pressure controlled lift adapted to be coupled to the source to move the core box into operative engagement with the discharge end of the transfer chamber, fluid pressure controlled means adapted to be coupled to the source to close the cover, valve means actuated by the cover closure for automatically applying liuid operating pressure from the source to the lift and to the sand transfer chamber, means for exhausting fluid pressure from the transfer chamber after the core blowing operation is completed, fluid pressure controlled means coacting therewith to automatically release the fluid operating pressure from the lift in response to a predetermined reduction of uid pressure within the transfer chamber, and other fluid pressure controlled means coactng in responseV to a predetermined reduction of the fluid operating pressure Within the lift to automatically remove the cover from the chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,300,148 Gilliland Oct. 27, 1942