US3077013A

US3077013A - Method and apparatus for centrifugal casting of pipe

Info

Publication number: US3077013A
Application number: US47541A
Authority: US
Inventors: Russell G Dishman
Original assignee: United States Pipe and Foundry Co LLC
Current assignee: United States Pipe and Foundry Co LLC
Priority date: 1960-08-04
Filing date: 1960-08-04
Publication date: 1963-02-12
Anticipated expiration: 1980-02-12

Description

Feb. 12, 1963 R. G. DlsHMAN METHOD AND APPARATUS FOR` CENTRIFUGAL- CASTING 0F PIPE 4 Sheets-Sheet l Filed Aug'. 4, 1960 Feb. l2, 1963 R. G. DlsHMAN 3,077,013A

METHOD AND APPARATUS FOR CENTRIFUGAL CASTING OF PIPE 4 Sheets-Sheet'I 2 Filed Aug. 4. 1960 50 INVENTOR.'

RUSSELL G. DlSHMAN ATTORNEY METHOD AND APPARATUS FOR CENTRIFUGAL CASTING 0F PIPE Filed Aug. 4. 1960 Feb. 12, 1963 R. G. DxsHMAN 4 Sheets-Sheet Z;

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IN VEN TOR."

RUSSELL. G. DISH MAN BY g j AT TOR N EY Feb. 12, 1963 R. G. DlsHMAN 3,077,013

METHOD AND APPARATUS FOR CENTRIF'UGAL CASTING OF PIPE Filed Aug. 4, 1960' 4 Sheets-Sheet 4 INVENTOR.' V

Russ E| G. DISHMAN ATTORN EY FIG 11 FIG. 13

3 @'77 @13 fslsll) AEPAATUUS FR CEN'MFUGL CSllslG (lll FHU'E lislnnan, Anniston, Ala., assigner, by mesne tents, to United States Pipe and Foundry @Conn pany, ns, Ala., a corporation of New .lersey I 1-, i960, Ser. No. $7,541

Qlainis. (Si. 22-l7) invention relates to a method and apparatus for the centrifugal casting of pipe. More particularly, this invention relates to a method. and apparatus including an expansibde mandrel used in conjunction with a spun flask for the centrifugal forming of pipe molds and the centrifugal casting ot the pipe.

Heretoiore, heavy orrn bars have been used, but only a limited numer of sizes could be made with the heavy form bar, Whereas according to my method and with my apparatus centrifugal force is employed to expand the mandrel. 'lne llaslt is normally maintained in horizontal position, thus accomplishing better results in less time than was heretofore required, but for lining purposes, specifically with green sand, it may be placed in the vertical position.

An object of my invention, therefore, is to provide a method and apparatus utilizing centrifugal force to assist in shaping the mold.

Another obiect or" my invention is to provide quick adjusting mechanism to obtain and maintain aroper size.

Another object of my invention is to provide apparatus which does not need to be of heavy construction to maintain proper alignment.

Another object or my invention is to provide a method and apparatus which is faster and more convenient in operation, and which produces better and more uniform results.

Another object of my invention is to provide apparatus which is simple in design, rugged in construction and meets the demands of economic manufacture.

Gtlier and further objects and advantages of my invention will be obvious from the following specification in conjunction with the accompanying drawings wherein like characters of reference designate the same or similar parts throughout the several views, and in winch:

FiG. l is a side elevation of apparatus for the centrifugal basting of pipe according to my invention.

FIG. 2 is a top plan View, on an enlarged scale, partly in cross section, showing the central portion of the ap paratus disclosed in PEG. l.

FlG. 3 is a cross sectional view taken along the line 5 3 in l.

F G. 4 is a cross sectional view talren along the line a top plan vieuI of the end portions of the A .tus shown in HG. 1.

tsr-G. 6 is an enlarged View ot the llasl; with parts away to show the cores and the pipe cast therein. J. 7 is a longitudinal cross sectional view of a detail 'ng the tiasl: with the mandrel tbeein in contracted nal view taken along 9 a view similar to FIG. 7, but showing the expanded position.

in i9 is a transverse cross sectional View taken rio. l

'Patented lieb. l2, ll

se it@ FIG. 13 is a view similar to FIG. ll with the mandrel in expanded position.

HG. 14 is a transverse cross sectional view talren along the line lLl--ld in FlG. i3.

Referring now more in detail to the drawings, the apparatus shown for purpose of illustration comprises a stationary base trame lil supportino a pair of parallel shafts Il, il" which are rotatably journaled in bearings l2, l2', respectively. Each of the shafts llt, ll. car ies a pair of trannie-rt Wheels i3, i3', respectively, which cradle a hollow tubular ilask ld. rhe flask lli is provided near its center with a circumferential guide ring l5 which is received between the ila-nges or" guide Wheel lo secured to shaft il to prevent longitudinal shifting of the lask. Also secured to shaft il is a pulley il' which is driven by a belt l running over a pulley on the motor 3.9. Hold-down straps 2d, Ztl provided with rollers 2l, 2l', respectivel are releasably fastened to the base frame lll by bolts 22, 2', respectively.

An auxiliary stationary frame 23 is positioned ad jacent the stationary base frame l@ and has rails 2li, 24' thereon upon which ride the wheels 25 of a movable carriage 26 which rotatably supports the mandrel 27 in

bearings

23, 23 so as to position the mandrel 27 in axial alignment with the liasl: le so as to be moved in and out of the llasl. upon movement of the carriage Z5 on the rails 124i, 2d. Motor 29 mounted on the auxiliary stationary frame 23 is arranged to rotate the mandrel 27 by means of belt 3@ trained over pulley 31 which is fixed to the mandrel El.

At the opposite end of the llask le is a movable frame 32 supported on Wheels 33 which ride on rails 3d, 343 for movement normal to the axis of the iiask lli. On top of the movable frame 32. is a movable carriage 355 slidably mounted for movement on the movable trarne 32 in a direction parallel to the axis of flask llt. The movable carriage 35 mounts an alignment shaft 35 which is freely rotatable in bearings 3'?, 37'. The movable carriage 35 is held in adjusted position by clamping means The alignment shaft 3a carries a mold former 39 for either a hub or a spigot end, here shown as a spigot end so that when the movable frame 32 is moved on the rails 3ft, 3e' to bring the alignment shaft 36 into axial alignment with the mandrel 27 in the ilask. le, the movable carriage 35 can be adjusted on the frame 32 to insert the mold former into the adjacent end of the ilasle llland mate the end of alignment straft Slt? with the adjacent end of the mandrel 2"? so as to maintain the mandrel in centered position with respect to the llaslt ld when the mandrel is driven by motor 29.

Hub forming blades dll, fil" are attached to the mandrel 2'? by means of adjusting bolts dl, dl', respectively, which are recessed in the mandrel and are loaded bv springs dit, dit', respectively, to urge the blades dit, dll in toward the mandrel, as shown in Fl'GS. ll-l2, but nerrnit outward movement of the blades de, 4G', as shown in FlGS. 1344, in response to centrifugal force when the mandrel is rotated.

Also carried by the mandrel 2'7 are a plurality of elonforrning blades 3 .fired by adjusting ons zh-t, dus respectively, which. are recessed 1n the mandrel 27 and are loaded by springs d, l5 respectively, to urge the blades 43 in toward the mandrel 27 when the mandrel is at rest but will permit movements of the blades d3, 43 outwardly in response to centrifugal force when the mandrel 27 is rotated. rlhe bolts 4l, di are provided with self-locking adjusting nuts ed, do', for adjustment of the outward movement of the hub forming blades lill, ltl in response to centrifugal force; and the barrel forming blades d3, 43' are provided with adi-usting bolts fr'/ having self'locking nuts 47 thereon for adjustment to limit the outward movement or" the barrel forming blades in aureola u response to centrifugal force, this adjustment being preset. The openings 52 and 52' are made sand tight by inserting a piece of wool felt cut to shape and glued into place.

ln the performance of my method, the flask 2.4i is heated to approximately 300 F. by any convenient means, such as portable torches (not shown) which can be inserted in either end of the flask.

Then when the flask has been heated, a resin-sand mixture is placed on the mandrel in the space between the forming blades, and the mandrel is then inserted into the flask by movement of the carriage 26. The chuck or alignment shaft 3o is then moved into alignment with the mandrel Z7 and adjustably positioned by movement of the carriage 35 so as to mate the alignment shaft or chuck with the mandrel. The preheated flask lid is then rotated in one direction by the motor i9 at about 6GB rpm., and then rotation of the mandrel Z7 is commenced in the opposite direction at about the same speed so as to cast the resinsand mixture onto the inside of the flask and smooth it out by the expanding mandrel, the blades of which are thrown outwardly by centrifugal force to push and compress theresin-sand or other mold material into the proper shape. After the mold material has been formed into the desired shape within the flask, the mandrel is withdrawn from the flask and the chuck removed from the other end of the flask preparatory to casting the pipe.

As an alternative to the use of the mandrel herein described, I have found that the resin-sand mixture may be blown into the preheated flask while it is being rotated at about 1000 rpm. to coat the inside of the heated flask and provide a smooth even coating all around the inner periphery, the blast being such that to insure an even coating throughout the length or" the flask an excess of material is used which passes through the flask and out the opposite end.

Having formed the mold inside the flask, as above de scribed, dry sand cores 48, .49 are inserted into the ends of the flask and fixed in place by means of tapered lock pins 50 or any other suitable securing means. Elben, While the flask is still warm, to avoid chilling the metal, the pouring horn (not shown) of prior art construction is moved into place and While the flask is being rotated at about 1000 r.p.m., depending somewhat upon the size of the pipe to be cast, a predetermined amount of molten metal is poured for the casting, and the rotation of the flask is continued until the molten metal solidiiies upon partial cooling, whereupon the bolts 22, 22 are loosened or withdrawn to permit release of the flask 11i from under the hold-down

yokes

26, 20 and then the ifi with the casting therein is removed from the trunnion wheels 13 and another flask is set in place.

ln addition to the resin-dry sand mold, this apparatus also lends itself to the making of green sand molds. Accordingly, a measured amount of sand is placed in the flask while it is either rotating or at rest. The flask is then set in fast rotation initially to pack the sand by centrifugal force. rhe expansible blades are then inserted and set in counter-rotation to the flask, which further packs and imparts a definite form to the sand. After placing the hub cores d and 49 in position, it is ready for spinning and pouring. A thin resin lining can then be blo-wn into the green sand mold and a portable burner used to cook the thin lining in just a few seconds. The net result is a casting that requires little or no cleaning. The green sand lining is designated by l, 5l. in resin lining, 5i, 51 are part of the flask itself. The spigot end or second hub cannot be formed on account of being unable to withdraw it. Conversely, it would be a plain end pipe.

Having thus described my method and apparatus, it will be obvious to those skilled in the art that many modifications and changes can be made without departing from either the spirit or scope of my invention as defined in the appended claims.

l claim:

1. In a method for the centrifugal casting of pipe, the

steps of forming a mold in a flask within which metal is cast comprising rotating said flask about an axis, introducing mold material into said flask for the formation of said mold within said flask, positioning a blade axially within said pipe and initially spaced from the inner periphery of said tlasl; by a distance greater than the thickness of the mold to be formed and smoothing the inner periphery of said mold by yieldably moving said blade radially outwardly toward the inner periphery of said flask a predetermined distance as said flask is rotated.

2. in a method for the centrifugal casting of pipe, the steps of forming a mold within which metal is cast comprising heating a ilask, rotating said flask about an axis, introducing mold material into said flask for the formation of said mold within said flask, positioning a blade axially within said pipe and initially spaced from the nner periphery of said flask by a distance greater than the 'thickness of the mold to be formed and smoothing the inner periphery of said mold by yieldably moving said blade radially outwardly toward the inner periphery of said flask a predetermined distance as said flask is rotated, and by rotating said blade in a direction opposite the direction of rotation of said flask during the movement of said blade radially.

3. In a method for the centrifugal casting of pipe, the steps of forming a mold within which metal is cast comprising a tubular flask, rotating said flask about an axis, blowing mold material into said flask for the formation or" said mold within said flask, positioning a blade axially within said pipe and initially spaced from the inner periphery of said flask by a distance greater than the thickness of the mold to be formed and smoothing the inner periphery of said mold by yieldably moving said blade by centrifugal force radially outwardly toward the inner periphery of said flask a predetermined distance as said flask is rotated and by rotating said blade in a direction opposite the direction of rotation of said flask during the movement of said blade radially.

4. In a method for the centrifugal casting of pipe, the steps of forming a mold within which metal is cast comprising heating a tubular ask, rotating said flask about an axis, introducing mold material into said flask for the formation of said mold within said ask, positioning a convex blade having a curvature corresponding to the curvature of said flask axially Within said pipe and initially spaced from the inner periphery of said flask by a distance greater than the thickness of the mold to be formed and smoothing the inner periphery of said mold by yieldably moving said blade by centrifugal force radially outwardly toward the inner periphery of said flask a predetermined distance as said flask is rotated and then returning said blade to its initial position.

5. In a method for the centrifugal casting of pipe, the steps of forming a mold within which metal is cast comprising a tubular flask, rotating said flask about an axis, introducing mold material into said flask for the formation of said mold within said flask, positioning opposed convex blades axially within said pipe and initially spaced from the inner periphery of said flask by a distance greater than the thickness of the mold to be formed and smoothing the inner periphery of said mold by simultaneously yieldably moving said blades by centrifugal force radially outwardly toward the inner periphery of said flask a predetermined distance as said flask is rotated by rotating said blades in a direction opposite the direction of rotation of said flask.

6. Apparatus for the centrifugal casting of pipe including a hollow tubular flask mounted for rotation about its longitudinal axis, means operably connected to rotate said flask, hold-down means passing over said flask for securing the flask in position for rotation, an expansible mandrel supported for rotation in axial alignment with said flask and movable in and out of the flask at one end thereof, alignment means mounted for movement into and out of engagement with said mandrel at the opposite end of said flask, means for continuously rotating said mandrel about its longitudinal axis, said mandrel including an elongated body and a forming blade mounted on said body for outward movement in response to centrifugal force, means urging said blade inwardly against centrifugal force, and means for limiting outward movement of said blade beyond a predetermined distance.

7. Apparatus for the centrifugal casting of pipe including a plurality of trunnion wheels for cradling a flask, a hollow tubular flask cradled on said trunnion wheels for rotation about its longitudinal axis, means operably con nccted to at least one of said trunnion wheels to rotate said flask, hold-down means passing over said flask for securing the flask in position for rotation on said trunnion wheels, an expansible mandrel supported for rotation in axial alignment with said flask and movable in and out of the flask at one end thereof, a freely rotatable alignment shaft mounted for movement into and out of engagement with said mandrel at the opposite end of said flask, means for continuously rotating said mandrel about its longitudinal axis, said mandrel including an elongated body and a forming blade mounted on said body for outward movement in response to centrifugal force, spring means urging said blade inwardly against centrifugal force, and means for limiting outward movement of said blade beyond a predetermined distance.

8. Apparatus for the centrifugal casting of pipe including a plurality of trunnion wheels for cradling a flask, a hollow tubular flask cradled on said trunnion wheels for rotation about its longitudinal axis, means operably connected to rotate said flask, hold-down means releasably secured to said frame and passing over said flask for securing the flask in position for rotation on said trunnion wheels, means operatively associated with said flask to prevent longitudinal shifting of said flask, an expansible mandrel supported for rotation in axial alignment with said flask and movable in and out of the flask at one end thereof, alignment means mounted for movement into and out of engagement with said mandrel at the opposite end of said flask, means for rotating said mandrel about its longitudinal axis, said mandrel including an elongated body and a forming blade mounted on said body for outward movement in response to centrifugal force, spring means urging said blade inwardly against centrifugal force, and means for limiting outward movement of said blade beyond a predetermined distance.

9. Apparatus for the centrifugal casting of pipe iricluding a hollow tubular flask mounted for rotation about its longitudinal axis, means operably connected to rotate said ask, an expansible mandrel supported for rotation in axial alignment with said flask and movable in and out of the flask at one end thereof, alignment means mounted for movement into and out of engagement with said mandrel at the opposite end of said flask, means operably connected to rotate said mandrel about its longitudinal axis, said mandrel including an elongated body and a plurality of forming blades mounted on said body for outward movement in response to centrifugal force, means urging said blades inwardly against centrifugal force, and means for limiting outward movement of said blades beyond a predetermined distance.

10. Apparatus for the centrifugal casting of pipe including a base frame, a pair of parallel shafts rotatably journaled in said frame, a plurality of trunnion wheels on each of said shafts for cradling a flask, a hollow tubular flask cradled on said trunnion wheels for rotation about its longitudinal axis, means operably connected to at least one of said shafts for at least certain of said trunnion wheels to rotate said flask, hold-down means releasably secured to said frame and passing over said flask for securing the flask in position for rotation by said trunnion wheels, means operatively associated with said flask to prevent longitudinal shifting of said flask, an expansible mandrel supported for rotation in axial alignment with said flask and movable in and out of tbe flask at one end thereof, a freely rotatable alignment shaft mounted for movement into and out of engagement with said mandrel at the opposite end of said flask, means for rotating said mandrel about its longitudinal axis, said mandrel including an elongated body and a plurality of forming blades mounted on said body for outward movement in response to centrifugal force, spring means urging said blades inwardly against centrifugal force, and adjustable means for limiting outward movement of said blades beyond a predetermined distance.

11. Apparatus for the centrifugal casting of pipe including a hollow tubular flask mounted for rotation about its longitudinal axis, means operably connected to rotate said flask, a mandrel supported outside said flask for rotation and extending into the hollow portion of said flask, means for rotating said mandrel, a blade means for yieldably mounting said blades on said mandrel for movement toward and away from the inner periphery of said flask, and means for urging said blades toward said mandrel whereby when said mandrel is rotated, said blade is urged outwardly and upon termination of the mandrel rotation said blade is urged inwardly.

l2. Apparatus for the centrifugal casting of pipe including a hollow tubular flask mounted for rotation about its longitudinal axis, means opcrably connected to rotate said tlask, a mandrel supported outside said flask for rotation and extending into the hollow portion of said flask, means for rotating said mandrel, blades yieldably mounted on said mandrel for movement toward and away from the inner periphery of said flask, and means for urging said blades toward said mandrel whereby when said mandrel is rotated said blade is urged outwardly and upon termination of the mandrel rotation said blade is urged inwardly.

References Cited in the file of this patent UNITED STATES PATENTS 1,110,282 Askew Sept. 8, 1914 1,504,497 Perry Aug. 12, 1924 1,573,089 Rice Feb. 16, 1926 2,499,900 Johnston Sept. 2l, 1948 2,731,690 Coupland et al. Jan. 24, 1956 2,956,318 Hothorn et al Oct. 18, 1960

Claims

1. IN A METHOD FOR THE CENTRIFUGAL CASTING OF PIPE, THE STEPS OF FORMING A MOLD IN A FLASK WITHIN WHICH METAL IS CAST COMPRISING ROTATING SAID FLASK ABOUT AN AXIS, INTRODUCING MOLD MATERIAL INTO SAID FLASK FOR THE FORMATION OF SAID MOLD WITHIN SAID FLASK, POSITIONING A BLADE AXIALLY WITHIN SAID PIPE AND INITIALLY SPACED FROM THE INNER PERIPHERY OF SAID FLASK BY A DISTANCE GREATER THAN THE THICKNESS OF THE MOLD TO BE FORMED AND SMOOTHING THE INNER PERIPHERY OF SAID MOLD BY YIELDABLY MOVING SAID BLADE RADIALLY OUTWARDLY TOWARD THE INNER PERIPHERY OF SAID FLASK A PREDETERMINED DISTANCE AS SAID FLASK IS ROTATED.