US2512071A - Apparatus for clamping molds in the centrifugal casting of pipe and the like - Google Patents

Description

June 20, 1950 J.' J. |-1Vo| AN,\..|R` v APPARATUS FOR CLAMPTNG NoLDs 1 2,512,071 N THE CENTRIFUGAL CASTING oF PIPES AND THE LIKE 2 Sheets-Sheet 1 Filed oct. i2. v194e;

INVENTOR. JH/v J/VoLA/v JR Agi A! ORA/EY June 20, 1950 J. J. NoLAN, JR v 2,512,071

' APPARATUS FOR CLAMPING M0 IN THE CENTRIFUGAL CASTING oF PIPEs n THE LIKE Filed Oct. l2, 1946 2 Sheets-Sheet 2 INVENTOR.

A TURZYEY Patented June 20, 1950 UNITED STATES PATENT QFFICE 2,512,071 APEARATUS Fon CLAMPl-NG MQLDS.. IN'- THE ETEWIFUGAL CASTINQFPLIPEN!! THE' Nolan, .New York, N.. X... assiener to The Centre! ,Feuedt Eemnes? Yesh- Ya e entretenu Met-1.1. Y

Appncationoctober 1.2, 1944s, serial-N0.- #03,023

1 Y 2 The .invention relates to the centrifugal .cylinder meld clamping mechanisms, .emmoyedin or .pipe and similar articles. the prag/tice et my intention, .this vmechahism- In my prior patent, No. 2,378,723, granted 'being Shown in locked position- With `.the .mold- 19,1945., i have disciosed an nnproyedmthog of halfyesinly W@Lestat Y mak-ine Vcast `iron Dine inuninsniatedpermefnsnt s: Figs.. 3 and 4 .are detail views partly in ,Gmssf moidasuch asatWo-partitonmold. The present section illustrating one form 0f doable .checkt invention relates to improvements .in .the conf telve or coupling which .can tbe used as .means struction and operation 0f Athe two-part molds iqconneeting thezhydramicylinderbf the moldxvhich are partieuiariypsefnl `in the practice of elarnningmechanism toasouncepi fiuidpnessnre that method, land which .are also useful .in tile 1&9 .for leaking the duid inthe cylinder l,under Ice'nitrfngalroasting ofjronpipe .by other `InethQC pressure. known to theart. 5 andshgw the Lconstruetion .andneraf In the practice of the method described in my tion of the mold tand mold securing means, .the prior patentaioresaid .a type .ofmold is selected mold :hetnefshown in icnossrsecton ,and .the mold Awhich permits rapid renom/ aloofthe casting S9 seeming-'meansbeingshownparthzincrossasection ithat such removal v.can tloe effected at the very and partly in eleva-tion. Eig. 5 (,taken .as indi? momentthatlthe.casting hassoiidied sucently cated ati-+5 in Eig. 2.). shows the mold halves .to .hold its form @ne .of the .featuresoi my clamped .together and Eig. ,6 .illustrates .the last tgl.

fra

present invention is the fproyision of .,mpI-Ovepart of 1the ,mold securngaoperation `orthe rst ments in the known types of two-part .molds .29 part or the moid releasingpperaton. a

L-iifhich facilitate rapdrernovalofthe casting and v"While:theinvention lrelates -Ktothe-eonstruotion thus increase lther usefulness rill the Vpltaic .Qf and operation of two-part molds and therefore the methodreferrezd to. is not .directly concer-ned -With the Ymeans .for

Two-part molds for centrifugal casting .hai/.e mounting .and rotating the Jrnold, it :is 'believed been proposed heretofore. I,have .found how- .that .thetinventoncwm 1b@ more fuhyunderstood eVeI--ifhottheeuse m'frsuc'hamoldsleads to serions when described in `its relation :to lone -form of Vpractical difcul-ties-fromthestandpontoimain.- complete casting machine -to which it Ais `applitainingfan efective sea1.between thefmoldpalts caloilA i,I'Ienee'FIhavesho'tvn alger-xeral` arrangeunfderftheconditionsencountered Aathigh speeds mem @finch .a machmn .Fig 1L .I Wqsh tpto of rotation; It Wm be apprecated-tmt Wi-th 'loe ciearlynnderstood; however', thattheinven# speeds as hlghlas 600:to-80.0.R. mfpourlng, .fion eig appuaz f-th "1; foams of' cm'g 'fOr-ffmc 'e fw Por''pwa ffofmoutntf machines: 1e-ait'ter-itatl effet the een -uga crees-are `crea' e -'loa e Weig .of i e I, lcast metal there addedlthefweght of the mold gaggedqol or pb sul" itself, the-'twohalvesg of^-whi-ch,iparted on aplane 35 t Whichcontainsior lies adjacent the axisgof rotabe 1y mt .02%- ce t tion, are urged -apart'wtthztremendous vforce .'tend- 9F al 4 `ing-to overcomethe-.restraining 4inuence of Whatn. n im pallo anged ro lzs ever means Avare employed to secure them to- ,glu "19' wn wle 1? Q01d ?lf`f gether. Ithas been-=a'1eadng .object of thisinl y I @fijne vention to provide improvements in the con: struction and operationfofltwo-part moldswhich make it possibleto maintain-an eiective seal at 'the f parti-ng iine leven under fthe adverse condi. ytions mentioned.

jA specific obiectf .thelinvention is` tofprovide `an improved-method rof securing togetherl'the two halves of a mold for `centrifugalcasting. "Other objectsand'# advantages will appear as the `"description proceeds.

The drawingsillustrate a 4preferred form. of my improved `'casting apparatus.

Fig. llisl-a side-elevatonalview.ofathe general arrangement.

chine, through a system of pulleys and the driving cables I2 and I3.

The mold comprises a cope half I4 and a drag half I5 secured together by a series of'clamping bands I6 and hydraulic cylinder mold clamping mechanism indicated generally at 20.

The ends of the mold, or either of them, may be provided with hubs I1 for forming, with or without the use of suitable cores, bells, flanges or other pipe end fittings. In this connection it should be observed that one of the important advantages of employing a two-part mold as opposedto a unitary mold from which the pipe is withdrawn endwise, is that such fittings can be formed on both ends of the pipe section. In practical operation, however, the use of two-part molds for centrifugal castingposes a serious problem in securing the mold halves together in such a way as to withstand the enormous centrifugal forces to which they are subjected and at the same time maintain an effective seal at the mold parting. It is to this problem that my invention is directed principally.

In accordance with my invention, the mold halves I4 and I5 are surrounded by steel bands comprising the band segments I8 and I9, and force is applied to the band segments by fluid pressure means (indicated generallyat 26, Figs. l and 2) to close the mold halves tightly together. In the construction illustrated, the mold halves I4, I5 are hingedly connected at one side as by means of pins 2| passing through overlapping portions of the band segments I8, I9. The band segments I9 are fixed to the drag half I5 of the mold in any suitable manner, for example, by welding. The band segments I8 may be secured in a similar manner to the cope half of the mold but I prefer that the cope half be left free so that it can be lifted off when the band segments I8 are swung open.

In my preferred construction the band segments I8 and I9 are arranged in pairs as shown in Figs. l and 2. Each pair of segments I8 are joined by an arcuate plate or web 22 which preferably is shorter than the band segments as seen best in Figs. 5 and 6. Similarly, an arcuate plate or web 23 extends between the band segments I9. The band segments I9 are welded or otherwise secured to the drag half I5 of the mold through the plate or web 23. The clearances 24, 25 provided between the bands I8 and I9 and the mold halves at points beyond the ends of the plates 22 and 23 make it possible to utilize the springiness of the steel bands to advantage in maintaining high clamping pressure against the mold halves once they have been locked together in the manner which I shall describe more fully below.

The locking ends of the band segments I8 and I9 are arranged to lie adjacent one another when the mold is closed. The locking ends of band segments I9 preferably are connected by a plate 21 welded or otherwise secured thereto. The hydraulic cylinder 26 of each clamping mechanism is fixed between the bands I9 in a position to bear against the plate 21 as best illustrated in Figs. 5 and 6. In practice these cylinders usually are welded in place although this is not essential and other securing means may be employed as desired. The piston rod 28, connected to piston 29 operating in the cylinder, is secured at its other end to a pin 30 which, in the construction shown, passes through an aperture 3I formed in a transverse member 32 fixed to the piston rod. Transverse member 32 is of such a length as to t between the pair of bands I9. The pin 30 extends through a pair of slots 33 in the bands I9, these slots extending in line with the cylinder 26. Pivotally mounted on the ends of pins 30 is a yoke 34 arranged for engagement with a pair of notches 35 formed in the ends of band segments I8.

When the piston 29 is in the retracted posi-- tion shown in Fig. 6 with the mold halves closed as shown in that View, the yoke 34 can be swung freely into and out of position for engagement with the notches 35 as will be understood by comparing the full line and dotted line positions of the yoke. As the piston advances in the cylinder, the yoke moves into the position shown in Fig. 5, engaging the notches 35 and thus clamping the mold halves tightly together.

The cylinders 26 are connected to a fluid conduit 36 having a valve 31 arranged to lock fluid in the cylinders under pressure. I have discovered that with this arrangement, upon feeding molten metal into the mold and rotating the mold, the heat of the metal distributed over the inside surface of the mold raises the temperature of the fluid locked in the cylinders and produces an increase in pressure, causing the mold halves to be clamped more tightly together as the mold is rotated during casting.

The yokes 36 o' the clamping mechanism can be quickly released by opening the valve 31 and withdrawing the fluid. In my preferred construction the cylinders iare connected to a second fluid conduit 38 which, through a valve 39,

may be placed in communication with a source of fluid pressure for speedy and positive retraction of the pistons 29 to unclarnp the mold.

The conduit pipes 36, 38 may be assembled in sections extending between the cylinders, the latter being formed with connecting passageways 40, 4I to which the pipe sections are attached as by screw-threaded engagement. Passageways 49, 4I are in communication with the respective ends of the cylinder providing communication therewith at the opposite sides of the piston as clearly shown in Figs. 5 and 6.

In my preferred construction the fluid conduits are arranged for connection to a pump or other source of fluid pressure (not shown) by inlet and outlet pipes 42, 43 through a four-way valve indicated somewhat diagrammatically at 44 (Fig. l).

Valves 31 and 39 may be of any suitable construction, and to illustrate my preferred embodiment I have shown in Figs. 3 and 4 a conventional type of self-sealing coupling which is well suited for this use. Couplings of this type permit ready attachment and detachment, and the action of coupling or uncoupling automatically unlocks or locks the ends of the two conduits as the case may be. As valves of this type are Well known and have been on theV market for a great many years, it will be unnecessary to explain their construction and operation in detail here. Suce it to say that there is a pair of check valves 46, l1 arranged to seal the ends of the respective coupling members 49, 59 by closing the apertures 5I, 52 thereof, these check valves being pressed into locked or sealing position by the coil springs 53, 54 when the coupling is taken apart as shown in Fig.v 4. When the coupling is put together as shown in Fig. 3, the check valves 46 and 41 are pressed away from their sealing positions by engagement with the ends of the opposing coupling members, opening a, fluid passage through the coupling.

,The mold halves I4 and I5 provided a cylindrical mold cavity 55 and have flat meeting faces 55, 5l', respectively, adjoining the mold cavity at the parting line,v and complementary inclined portions 58, 59 adjacent the outer portion of the flat meeting faces arranged to be wedged together when the mold halves are closed tightly. With particular reference to Fig. 5, it will be observed that when the mold halves are closed tightly, the at faces 56 and 51 and the inclined surfaces 56 and 59 are in contact, but a clearance is provided at B9. I have found that a much more effective seal can be obtained when this clearance is provided so that the molds are in tight contact along the fiat faces 56 and 57 and also along the inclined wedged surfaces '58, 59 with clearance provided at other points.

The mold halves I4 and I5 preferably are also provided with complementary inclined surfaces near the ends of the mold as indicated at 6I, 6I in Fig. 1 to give a wedging effect as the mold halves are drawn together.

The mold clamping mechanism '29 can be used at one or both sides of the mold. If at both sides, the construction shown is duplicated at the opposite side, being substituted for the hinged connection 2|. are duplicated at the opposite side, and the two sets of conduits can be joined together at the end of the mold (right hand end as viewed in Fig. 1) so that a single set of valves 3l, 39 serves for the clamping mechanism 20 at both sides of the mold. The band segments I8 can be permanently attached to the cope half I4 of the mold, and the notches 35 are formed in both ends of these band segments. Both ends of band segments I9 are formed in the same way for attachment of the hydraulic cylinders 26, yokes 34 and other associated mechanism I have described.

In the practice of my method, using the form of apparatus specifically described herein, the mold is iirst assembled for casting by lowering the cope half I4 onto the drag half I5 as with the use of a chain hoist attached to the ends of the cope or to the ends of a bar supporting the same. When the cope is lowered into place, the band segments I8 are in the position shown in dot dash lines in Fig. 6 and the yokes 34 of the clamping mechanism are dropped down out of the way with the piston retracted as shown in Fig. 6. The band segments I8 are then brought into the position shown in full lines in Fig. 6 and the yokes are swung into the position shown in full lines in this same view. With the yokes in this position, couplings 3'I and 39 are closed and the four-way valve 44 operated to connect the conduit 36 with the inlet pipe 42 and the conduit 38 with the outlet pipe 43. Water or other liquid under high pressure is thus admitted above the pistons 29 and the liquid below the lpistons flows back to the Also, the fluid conduits 36 and 38` shown in Fig. 6 to that shown in Fig. 5 and clamp the mold halves tightly together. Assuming that the surface of mold cavity 55 has been prepared for casting, molten metal is now fed into the mold and the mold is rotated to distribute the metal over the inside of the mold and raise the temperature of the fluid locked in the hydraulic cylinders 26, whereby an increased pressure is produced within the cylinders, causing the mold halves to be clamped more tightly together as the mold is rotated Vduring casting.

When the mold clamping mechanism is employed at both sides of the mold as I have described previously, exactly the same procedure is followed except that after assembling the mold for casting by lowering the cope half I4 onto the drag half I5, the step of bringing the band segments I8 from the dot-dash position shown in Fig. -6 into the position shown in full lines in that view is eliminated because these band segments are permanently attached to the cope half I4 of the mold. Instead, the yokes 34 of the clamping mechanism at both sides of the mold are swung into the position indicated in full lines in Fig. 6, and the operation is continued as I have described above.

The terms and expressions which I have empleyed are used in a descriptive and not a limiting sense, and I have no intention of excluding such equivalents of the invention described, or of portions thereof, as fall within the purview of the claim.

I claim:

.A multi-part metal centrifugal pipe casting mold having fluid pressure clamping devices mounted in heat conducting relationship with the metal of the mold, and a valve for locking fluid in the clamping devices, said valve being mounted on the mold for rotation therewith and having a detachable connection to a source of fluid pressure, whereby the clamping devices can be disconnected from the pressure source before rotation of the mold and remain disconnected during rotation of the mold.

JOI-IN J. NOLAN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Apr. 18, 1918

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