US2122022A

US2122022A - Molding apparatus

Info

Publication number: US2122022A
Authority: US
Publication date: 1938-06-28
Anticipated expiration: 1955-06-28

Description

D. .J, CAMPBELL June 28, 1938.

Momma Ammamus Filed oct.' 21, i935 1 4 Sheets-Sheet 1 Y `lune 28, 1938. D 1 CAMPBELL 2,122,022

MOLDING APARATUS Filed Oct. 21,v 1955 4 Sheets-Sheet 2 Donald Campbell .0m wia-WJ@ (-orus `Jun@ 2s, 193s. DJCAMPBELL 2,122,022

MOLDING APPARATUS @Komme "v June 28, 1938. y D. J. CAMPBELL.

MOLDING APPARATUS Filed Oct. 2l, 1935 4 Sheets-Sheet 4 ono Q5. Canmben @Y i/2A Gimme.A

Patented June 1938 This invention NPATEN'I oFFlcE rMomma, APPARATUS Donald J. Campbell, Spring Imke Township, t-

tawa County, Mich., assigner to Campbell, Wyant Cannon Foundry Company, Muskegon Heights, Mich., a corporation of Michigan Application October 21, 1935, Serial No. 45,907

'-1s calm. loi. zz-zs) Y i relates` to molding machines and particularly to molding machines of the type used in foundries for producing sand molds from .ciA

a pattern of the metal castings to be made.

Foundry sand molds are customarily contained in foundry flasks whichare in the nature of several-sided frames and a portion of having open tops and bottoms the pattern is customarily attached to a follow board laid in one of the open sides of the ask sand is placed Withinv the flask against the pattern cope or drag, after which' the extend at spaced itsk upper side and intervals across the ask near resist and interfere 'with movement of the sand toward the pattern in the flask. It is necessary to pack the sand uniformly throughout the mold and especially around the pattern in order to obtain true-to-pattern casting.

and'it is the object of the present invention to provide means for squeezing the sand in the .mold

from opposite directions whereby its compactness will be substanti ally uniform throughout the whole mold and whereby the sand ywill be uniformly compressed against the pattern.

Another object of the invention is to provide a power operated mechanism for expeditiously and efficiently performing the molding operation.

`A further object of the invention is to provide of the mechanism This invention means for automatically controlling the operation provides various other novel features of construction and `arrangement as hereinafter more fully `described and particularly pointed out in th e claims and reference tothe accompanying drawings in. which:-

Fig. 1 is a transverse sectional elevation of a molding machine embodying this invention showing a flask, pattern and sand in position to como mence the squeezing operation.

Fig. 2 is the same as Fig. 1 with parts broken away and showing the iirst step of the squeezing operation in which the sand is compressedin the upper portion of the mold.

.Fig.3 is the same as Fig. A2 showing the completion of the squeezingv operation in which they "sand is compressed in the lower portion of the mold.

Fig. 4 is a sectio nal elevation at right angles to Fig. 3 showing the parts in the saine position as Fig. 3. v f Y Fig. 5 is a fragmentary elevation, partially in section, of the automatic control valve and associated parts. i

Figs. 6, '7v and 8 are enlarged sectional elevations of the automatic control valve shown in three different positions. I

Fig. 9 is an enlarged sectional plan of the control valve on the line 3-9 of Fig. 7, and

Fig. is an enlarged sectional plan of the automatic control valve on the line III-I0 of Fig. '7.

Like numbers refer to like 'parts in all oi the iigures.

The machine has a base I upon which is formed a Vertical cylinder 2. The cylinder 2 is provided vwith a hollow piston 3, the interior of which forms a cylinder for theinner piston l. Each of the pistons Sand 4 projects from the upper end of its respective cylinder.

The outer piston 3 has an outwardly extending4 apron 5 which serves as a guard to prevent sand and other foreign matter from entering the upper end of the cylinder 2 and the apron 5 also serves as a support for the threaded adjustable bars 6 which extend upwardly and carry at their upper ends a. supporting frame 1. The members 6 are in the nature of screw threaded bars and extend through lugs 8 vand are locked relative therewith by nuts 9 above and below each lug and whereby they may be longitudinally adjusted. The bars B are preferably four in `number arranged in spaced relation with leach other at the sides of the supporting frame 1.

The pattern III, which is to form the mold cavity,v is usually mounted on a patternplate II and the pattern plate is supported on a table I2 which is fixed to the upper end of the inner piston 4 and in the structure shown is integrally formed therewith. 'I'he table I 2 is approximately the same shape and size as the inside of the supporting frame 1 and is arranged to slide vertically therein, the supporting frame 1 being preferably pron vided with a removable lining 1a which may be provided with adjliltable stop bolts I5 which likewise extend downwardly through bracket I6 on a iixed portion of the machine. The stop bolts I5 are screw threaded into the apron and have heads at their lower ends, which heads engage the lugs I6 to limit the upward movement of the outer piston 3 and the extent of such upward movement may be adjusted by the screw thread attachment of the bolts in the apron 5.

. The mold ask Il is the same size interiorly as the supporting frame l and is removably supso that it may be handled Without detriment. A

dummy frame |9,shown in dotted lines in Fig. 1, is provided to be placed upon the upper surface of the flask and is used when filling the flask with sand as hereafter described.

A pressure head 29 is arranged to be located over the fiask and is mounted on a pivoted arm 2I. 'I'he head is provided with a heini-spherical bearing member 22 on its upper surface, which bearing member ts into a socket 23 on the end of the arm 2| and a bolt 24 passes loosely through an opening 25 in the arm and is provided with a nut 26 at its upper end, which nut bears against a washer and a flexible disk 2l toprovide a slight self-aliningmovement of the head relative to the arm.

'I'he arm 2| is pivoted at 28 to a bracket 29 which bracket is attached for vertical adjustment on a vertical frame member 30 forming a part of the base I. A jackscrew 3I supports the bracket 29 in adjusted position. Power means for swinging the pivoted arm 2| is provided and consists of a toggle lever having a lower link 32 pivoted at 33 to the bracket 29 and pivoted at its upper end at 34 to the lower end of the upper link 35 which upper link is pivoted at 36 to the arm 2I at a point in spaced relation to the pivot 28 of the arm 2i.

The upper link 35 is in the nature of a bell crank, it having an arm 31 to which is connected a piston rod 38 which piston rod is connected to a piston which operates in a conventional type of cylinder 39. The cylinder 39 is mounted on a trunnion 49 on the arm 2| and is provided with conduits 4I at its respective ends through which fluid under pressure may be introduced to operate the piston in the cylinder. The details of construction of the cylinder 39 and its piston are not shown inasmuch as they are of a conventional and well-known nature and form no specific part of this invention. A guide pin 42 extends upwardly from the pressure head 20 at a distance from its connection with the arm and slidably extends through a portion of the arm to prevent rotation of the head relative to the arm but with suicient clearance to permit a limited self-alining movement thereof.

'I'he

pistons

3 and 4 are adapted to be operated in their respective cylinders by uid pressure, preferably compressed air, and a valve is provided to control and direct the iow of the compressed :duid to actuate the pistons in proper sequence and in the desired manner. A manually operated valve is. also provided in the air supply conduit to commence the operation of the pistons and to cut olf the air pressure and permit the pistons to return to normal position.

The main compressed uid supply conduit 43 leadsV from a convenient source of supply; a

whereby the compressed fluid may be permitted to pass through the valve to the operating valve beyond or cut off and exhausted through the port 46.

The operating valvemechanism comprises a piston valve, a vertical cylinder 4l having an inlet port 48 and two

outlet ports

49 and 50 respectively. The inlet port 48 and the outlet port 49 are located near the upper end of the cylinder 4l in substantially the same piane and may be diametrically opposite each other as shown. 'I'he outlet port 50 is located at the lower end of the 'cylinder in the cylinder head 5I and communicates with a passage 52 extending upwardly through an axially located post 53 which post is fixed to the .cylinder head 5I, being preferably formed integral therewith. The iiuid pressure supply conduit 43 communicates with the inlet port 48 and the outlet ports 49 and 5I) communicate with the outer and

inner cylinders

2 and 3 respectively.

A conduit 54 serves as the communication between the outlet port 49 and a passage 55 in the base of the machine which passage enters the lower end of the outer cylinder 2. A exible conduit 56 extends from the outlet port 50 to a pipe 5l mounted on the inner piston 4 which pipe communicates with a passage through the lower head of said piston thereby directing the iiuid into the inner cylinder 3. It will be remembered that the cylinder 3 is in the nature of a hollow piston serving as a piston in the outer cylinder 2 and also as a cylinder for the inner piston 4.

The cylinder41is provided with a valve 58 which piston valve has an axial opening 59 in its lower end to slidably receive the vertical post 53, said opening and post acting as a piston valve. The valve 58 isprovided near its upper end with an annular space 60 which registers with both

thel ports

48 and 49 in any of its positions thereby insuring an open passage or communication between said ports at all times. 'I'he passage 52 in the post 53 extends upwardly through the upper end of the post and in which lateral ports 6I are provided extending from the passage 52'through the wall of the post to the exterior thereof.

Ports 62 extend from the opening 59 of the piston valve 58 to the annular groove 60, their lower ends communicating with the axial opening 59 near the bottom of the valve. When the valve 58 is in lower position the passages 62 are closed at their lower ends by the outer surface of the post 53 but when the valve is raised the lower ends of the passages 62 communicate with the openings 6| in the post and thus provide air passages from either of the

ports

48 and 49 through the annular space 60, through the body of the valve and into the passage 52 communicating with the outlet port 50. An annular groove Sla is preferably provided on the outer side of the post 53 communicating with the opening 6I to insure communication between-the passages 62 and the opening 6I regardless of the rotary position of the valve.

A restricted opening 63 extends from at least one of the ports 62 tolthe axial opening-*[59 at a point somewhat above the openings of the passages 62 into said axial `opening 59. This restricted passage is out of communication with the openings 6I when the piston is in lowered position but communicates with said openings 6I when the piston is partly raised.

A valve stem 64 is attached to the valve 58 and extends through a stufllng box 65 in the head of vthe cylinder 41 and isprovided vnear its free end with a yieldable stop66. 'I'he stop 66 has a ball 61 pressed inwardly by spring `68 and normally engages a notch or annular groove 69 provided near the end ofthe valve stern 64. by engaging the groove forms a yieldable stop for the stem 64. 'The voperating valve is mounted s on some fixed portion of the machine sch as the bracket -I6 and an arm 10 extends from some portion of -the outer piston 3 such as the apron 5 thereof and the outer end vof the arm is adjacent the valve stem 64 and is preferably forked to embrace the stem. A cushion washer 1I .is preferably laid on` top of the outer end of the arm 10 andupward movement of the outer piston 3 car-` ries the arm 10 upward and engages the washer 1I with the collar 66'toraise thevalve 58 of the operatingvalve. The spring pressed ball 61 will yield un`der abnormal pressure and permit -the stop 66 to slide on the stem 64 to prevent breakage.

compression vin the several cylinders are illustrated ,in the several pistons and valve of the machine but have not been .specifically referred to as their use is common practice.

Relief openings

12 and 13 are provided at the respective upperand lower ends of the cylinder 41 above and below the valve 58 to insure free movement of the piston in the cylinder.

Operation vWhen a proper pattern, as I l), and pattern plate I I are mounted on the .table I2 and the machine has been properly adjusted for operation, the armV 2|' carryingv Athe pressure'4 head 26 is swung upwardly and rearwardly by action of the fluid pressure against the piston in the cylinder 39 acting upon the toggle links 32 and 35. 'I'he hand lever 45 ofthevalve 44 is turned to shut-off position and the

pistons

3 and 4 are in lowered position. In this position thepattern and patternv plate I and II will be lowered into the supporting vframe 'l as` shown in Fig. 1.y then placed on thesupporting frame land the dummy frame I9 is placed on the upper edge ofr The operator then deposits sand above the pattern and pattern plate insumcient the flask I 1.

quantity to fill,v the supporting frame 1 above the pattern plate and to completely flll the flask I1 and dummy frame I9. He then strikes off the surplus sand flush with the upper surface of the dummy .frame I9 and removes thedummy frame thereby leavingL a quantity of sand projecting above the upper edge of the flask I1. 'Ihe arm 2I and pressure head 20 are then swung forwardly and downwardly by action of thepiston in the cylinder 39 land coacting parts above referred to,

the `parts being soA arrangedfandr adjusted that this forward and downwardfmovement will stop with the lower surface of the pressure head 20 in engagement with the'surface of the sand in the flask.

' It is advisable to ilrst perform the topsqueeze that is, to compress or squeeze the sand above the upper portionof the flask left by the removal of The ballv 51 Various sealing rings to prevent leakage of l The flask I1 is the dummy frame into the flask, which action is accomplished by upward movement of the outer piston '31 forcing lthe flask against the pressure head 20 and corresponding lower squeeze is then made by the upward movement of the inner piston 4 which carries the table I2 and pattern plate II. In other words all of the supporting members,

v move upwardly, carrying the pattern with the lower portion of the flask and around the pattern. 120

This actionis accomplished by movement of the inner piston 4 Withinthe outerv piston 3 as the outer piston is held in raised position.

Thefpistons are actuated as above described by means of compressed air or other pressure fluid admitted to the respective cylinders inthe proper sequence by actuationvof the manual valve and the operating valve. To start the operation the lever 45 is turned to openl position of the valve.

The fluid passage through the valve 44 'is then opened and admits pressure fluid into the port 48 from where it passes around the annular groove 60 and out through the port 49, through the conductor 54, the passage 55 and into the lowerv end of the cylinder 2.

The position of-thev operating'valve at the beginning of the koperation is shown in Fig. 6; As the fluid enters the cylinder 2 it raises the outer piston 3, and also the inner piston 4 which is supported within it, .thus carrying all of the supporting members upwardly as above described and compressing 4the sand against thepressure head 20. This movement requires kthat heavy pressurebe exerted to sumciently compress'the sand. As theparts, including piston 3, move upwardly, the arm 10 mounted on the apron 5 of theouter piston 3 rises'and when the stroke has been completed the arm engages the collar 66 and Acarries the valve 58 upwardly.

As the piston is moved upwardly the restricted passage 63. registers with an opening 6I and admits a restricted flow of compressed fluid through a passage 62, the opening 6I,and through the various passages and

conductors

52, 50, 56 and 51 into the innercylinder 3. v Admitting fluid pressure in a restricted quantityin this manner slowly builds up a pressure in the inner cylinder below the piston 4 during the time that the several supporting parts are being moved upwardlyby presy sure in the outer cylinder below the piston 3 until eventuallysuch pressure is, accumulated that will raise the piston 4 and in so doing raise valve 58 to the top of its upwardtravel.

This is accomplished by virtue of thefact that the fluid pressure within the passages leading to the inner cylinder below ythe piston 4 also acts directly upon the upper end of the opening 59 in `the valve and when such pressure is great enough the valvev will be lifted to the top of its travel. The intermediate position of the valve 58 is shown inFig. 7 wherein the arm 10 has raised the valve 58 to register the restricted passage 63 with an opening 6I. u

The final position of the. valve 58 is shown in fluid pressure to the top of its travel. In thefflnal Fig. `8 wherein the valve-58 has been raised by position of the valve all of the passages 62 register with the'openings 6I which affords a relatively free passage of fluid pressure through these ports and openings andthrough said passages and

conductors

50, 52, 56 and 5l to the interior of the inner cylinder which causes the inner piston i to rise relative to the outer piston and accomplishes the bottom squeeze by raising the pattern and pattern plate within the supporting frame 1. In this latter movement the pressure to raise the iner piston t is also acting oppositely against the lower end of the outer piston 3 but it will be noted that the area of the end'of the piston 3 exposed vto the same pressure is greater than that of the inner piston and therefore the outer piston will remain raised.

The upward movement of the pattern and pattern plate and the table i2 on which they are supported is limited by engagement of the Stop 12a with the under side of the supporting frame 1. In this position the top of the pattern-plate is substantially flush with the lower edge of the ask. The upward movement of the outer piston 3 is stopped by engagement of the heads of the stop bolts l5 with the bosses I6. These stop bolts are adjusted `to stop the movement with the upper edge of the flask i l in engagement with the lower surface of the pressure head 20.

After the sand has thus been squeezed both top and bottom it is desirable to return the parts to normal position and at the same time perform the sci-called stripping action, that is, to withdraw the pattern from the mold. The reverse operation is eected by manual operation of the valve d4, turning the lever 45 to shut off the supply of fluid pressure and at the same time opens the exhaust passage which permits pressure to flow backwardly through the valve and through the exhaust port 46. When the valve has been so turned air in both the inner and outer cylinders will escape through the conduits and passages to the operating valve which is then in the position shown in Fig. 8 and affords a free outlet from the ports t9 and 5I) to the port t8 from where it escapes through the valve 4'4.

As the pressure fluid escapes from the cylinders `the respective pistons therein will lower and carry the flask containing the mold away from the pressure head and at the same time lowering the pattern plate and pattern within the supporting frame 'i and away from the mold which is held supported in the flask on top of the supporting frame.

During the return movement, pressure fluid escapes from both

cylinders

2 and 3 simultaneously, the pressure fluid from the outer cylinder 2 escapes through the port 49 and the annular groove 60 and the port 48 while pressure fluid from the inner cylinder 3 escapes through the port 50 and the

passages

52, 6| and 62 into said annular groove 60 and out of the port 48. Both

pistons

4 and 3 will lower in their respective cylinders simultaneously until each has reached the bottom of its stroke and during this operation the valve 58 is held in raised position by pressure of the escaping air against the upper end of the axial opening 59 therein in which position the openings 6I register with the passages 62 to permit a substantially unobstructed flow of pressure fluid.

After the pressure fluid ceases tofiow from the

cylinders

2 and 3, and particularly from the cylinder 3, thepressure against the upper end of the axial opening 59 ceases whereupon the valve 58 will lower to its original or normal position shownin Fig. 6, the small amount of pressure fluid necessarily displaced from the upper end of the axial opening 59 to permit this movement being passed 01T by ordinary leakage. It will be understood that the arm 'l0 has been lowered with the cylinder 3 to Whichit is attached which will permit the valve 58 to lower.

After the parts have returned to their lowered or normal position they will again be in the position shown in Fig. 1 excepting that the sand will be compressed in the mold and the pressure head 20 may then be swung upwardly and rearwardly out of the way to permit removal of the flask with the mold. In these relative positions the completed mold with the sand squeezed there- -in will be supported within its flask Il upon the upper edge of the supporting frame 'l and the pattern I0 will be withdrawn from the mold and will be located in a position below it and thus the completed mold may be readily lifted out of the machine after which another flask is placed in position on the supporting plate, filled with sand as heretofore described and the operation of producing another mold repeated.

I claim:

1. A molding machine comprising, means for supporting a flask to contain sand for'a mold, a pattern associated therewith, means for supporting said pattern, a pressure head above said flask, means for moving said flask upwardly toward said pressure head for the purpose of compressing sand into the top side of said fiask into said flask from adjacent thetop of said flask, means for maintaining the flask in its upper position, and means for raising said pattern plate and pattern while the flask is in its upper position for the purpose of compressing sand from the lower side of the flask into said ask and against the pattern.

2. A molding machine comprising, means for supporting a pattern, means for supporting a flask elevated above said pattern, said iiask being adapted to contain sand deposited therein around said pattern, a pressure head above said flask, means for raising said flask and. pattern toward said pressure head, means for holding the ask in its raised position and means for raising said pattern relative to said flask and pressure head.

8.` A molding machine comprising, a supporting frame, a ask located above said supporting frame, a pattern supported for vertical movement in said supporting frame and 'adapted to be lowered below said flask, said flask having open upper and lower sides and said supporting frame having an open upper side and said flask and supporting frame being adapted to receive sand above said pattern, a pressure head located above said flask and means for raising said flask, supporting frame and pattern toward said pressure head for the purpose of compressing the sand in the ask and around the pattern from both the upper and lower sides thereof, said raising means functioning in immediate sequence upon the frame and pattern.

4. A molding machine comprising, a supporting frame, a iiask located above said supporting frame, a pattern supported for vertical movement in said supporting frame and adapted to be lowered below said flask, said ask having open upper and lower sides and said supporting frame having an open upper side and said flask and supporting frame being adapted to receive sand 'above said pattern, a pressure head located above said ask, means' for raising the supporting plate and pattern located in said supporting' frame and carried by said inner piston, a pres-- frame, ask and pattern simultaneously toward saidl pressure head and Ameans for raising the pattern within the said supporting frame towardI said flask and pressure -head.

5.. A molding machine comprising. a support-l ing frame, a-vertically movable member within .said supporting frame serving as 'a movable bottom therefor, a pattern mounted on said vertically movable member, a ask mounted above said supportingl frame, said flask having open 'upper and lower sides and said supporting frame having an open upper side andvsaid flask and k supporting frame being adapted to receive sand above said vertically movable member and pattern thereon, a pressure head located above said flask, means for simultaneously raising said supporting frame, flask, vertically movable member and pattern toward said pressure head, and means for raising the vertically movable member and pattern within the supporting frame and relative to said flask and pressure head.

6. A molding machine comprising, means for supporting a ask, means for supporting 'a pattern associated with saidask, said flask vbeing Y sure actuated means.

7. A molding machine comprising, `means for supporting aflask, means for supporting apattern associated with said ilask, said flask being adapted to contain sand around said pattern, a pressure head above said flask, fluid pressure actuated means forraising said flask toward said Apressure head, uid pressure actuated means for raising said pattern relative to said'fiask and pressure head and automatic means to control the fluid Vpressure for operation of both of said pressure actuated means.

8. A molding machine comprising, means for supporting a flask to receive sand around a pattern associated therewith, means for supporting said pattern, a pressure head above said flask, means for moving said flask upwardly toward said pressure head for the purpose of compressing sand from the upper side in said flask, means forraising said pattern for the purpose of compressing sand from the lower side around said pattern in said flask, and automatic means for contro-lling the movements of both of said flask moving means and said pattern moving means.

9. A molding machine comprising, means for supporting a flask to receive sand around the pattern associated therewith, means for supporting said pattern, a pressure head above said flask, means for simultaneously moving said ilask and pattern upwardly toward lthe pressure head,

,'means for raising said pattern relative to said flask and pressure head and automatic means for controlling the movements of both of said -ilask moving means and said pattern movingA sure head located above said flask and means for injecting compressed fluid lntosaid fixed cylinder, means for maintaining it therein, and additional means for injecting fluidr into said combinedpiston and cylinder to elevate therespective pistons therein.

11. A molding machine comprising.,V a Vilxed vertical cylinder, a combined piston and cylinderfth'erein, a supporting frame carried by said combined. piston' and cylinder, a flask supported i by said supporting frame, said ask having open upper and lower sides and said supporting frame having an open upper side, an inner piston 1in said lcombined piston vand cylinder, a pattern f plate and Apattern located in said supporting frame and carried b'y said inner piston, a pressure Ahead located above saidy flask, meansfor injecting fluid into said fixed cylinder. and said combined piston and cylinder to` 'elevate the respective pistons therein, and means for limiting the upwardmovement of the inner piston relative to the combined piston and cylinder.`

12. A` molding'machine comprising, a fixedA located above said flask, means for injecting fluid into said fixed cylinder, then into both the fixed cylinder and said combined piston and cylinder and thenv'intosaid combined piston and cylinder to relevate the respective pistons in sequence, means for limiting the upward movement of said combined piston and cylinder relative to said fixed cylinder, and means for limiting the'movement ofthe inner piston relative tothe combined piston and cylinder.

- 13. A molding j machine comprising, a fixed vertical cylinder, a combined piston and cylinder therein, a supporting frame mounted on said combined piston andcylinder, a flask mounteda on said supporting frame, a pressure head over `said flask, an inner piston in said combined piston and cylinder, a pattern and pattern plate located `within said-supporting frame and mounted on said inner piston, and an automatic fluid control valve connected with a source of fluid pressure and also connected with said fixed cylinder and said combined piston and cylinder and provided with means4 for first directing fluid to said ilxed cylinder and then for directing fluid to said combined piston and cylinder.

14. A molding machine comprising a fixed vertical cylinder, a.y combined piston and cylinder therein, a supporting frame mounted on said combinedpiston andcylinder, a pressure head over said frame, an inner piston slidable in said combined piston and cylinder, a pattern located Within said supporting frame and mounted on said inner piston, an automatic fluid control valve connected with a source ofA fluid pressure and also connectedfwith said fixed cylinder and said combined piston and cylinder and provided with means for directing the fluid to said fixed cylinder and additional means-for directing thek f1uid`to said combined piston and cylinder and means for operating said additional means, said operating means being `operated bymovement of the combined piston and cylinder to a. predetermined position.

15. A molding machine as set forth in claim 14 in which a reservoir of predetermined size is provided between -the inner piston and the combined piston and cylinder and means for causingA a ilow of pressure uid therebetween simultaneously with the concluding movement of the pressure ow to the xed vertical cylinder.

16. A combination of elements as set forth in claim 14 in which the automatic uid control valve is actuated by a vertically movable member, said vertical movable member being rigidly attached to the outer piston, said automatic uid control valve having means therewithin for providing a restricted flow due to the actuation by said extension and also having means for providing full and complete ow of pressure uid to the space between the inner piston and the combined piston cylinder in which it is mounted.

17. i molding machine of the class described comprising. a base, a. cylinder rigidly formed therewith. a. combined piston and cylinder slidably mounted :ln the said cylinder, an extension extending outwardly from the top of the combined piston and cylinder, a table, means for mounting the table on said extensions, a mold receivable upon said table, a piston slidably mounted within the combined piston and cylinder, a pattern mounted upon the top of said piston and means for introducing uid pressure between the cylinder and the combined piston and cylinder and also between the combined piston and cylinder and the piston located within the same.

18. A molding machine as set forth in claim 14 in which additional extensions are formed on the combined piston and cylinder, and lost motion means are associated therewith and with the said base whereby the upward movement of the mold is limited.

' DONALD J. CAMPBELL.