US3412785A

US3412785A - Core support for a centrifugal casting mould for casting pipes having a socket, and mould provided with said support

Info

Publication number: US3412785A
Application number: US566114A
Authority: US
Inventors: Lorang Pierre Edouard
Original assignee: CT DE RECH S DE PONT A MOUSSOU
Current assignee: CENTRE DE RECHERCHES DE PONT-A-MOUSSOU; CT DE RECH S DE PONT A MOUSSOU
Priority date: 1965-07-26
Filing date: 1966-07-18
Publication date: 1968-11-26
Anticipated expiration: 1985-11-26
Also published as: GB1091617A; CH461717A; BE683488A; DE1290671B; ES329643A1; FR1452172A

Description

CORE SUPPORT FOR A CENTRIE'UGAL CASTING MOULD FOR CASTING PIPES HAVING A SOCKET, AND

MOULD PROVIDED WITH SAID SUPPORT Filed July 18, 1966 2 Sheets-Sheet l Nov. 26, 1968 P. E. LORANG 3,412,785

Fig.2

' J lnvenfar:

P/ena dav d LaRANfi Nov. 26, 1968 P. E LORANG 3,412,785

CORE SUPPORT FOR A CENTRIFUGAL CASTING MOULD FOR CASTING PIPES HAVING A SOCKET, AND

MOULD PROVIDED WITH SAID SUPPORT Filed July 18, 1966 2 Sheets-Sheet 2 Fig.3

T 'l I iz v //VV-N 7'8 R Pierre. Edouard LORANG- United States Patent M 9 Claims. (a. 164-292) The present invention relates to centrifugal casting moulds for casting pipes having a socket and in particular but not exclusively to moulds for casting cast iron pipes.

It is known that moulds of this type comprise a core which imparts the internal shape of the socket. This core is supported by a device (yoke) comprising centering means for centering it in the mould and locking means for maintaining it firmly in position in the course of the high-speed rotation of the mould and resisting the centrifugal pressure of the liquid iron.

As the core is of sand and is used for only one casting operation, not only must its support be withdrawable as is known by pivoting or tilting so as to permit the extraction of the cast pipes and the replacement of the destroyed core by a fresh core, but the support must be so designed as to permit rapidly positioning and perfectly centering each new core.

Core-locking devices are known which comprise lugs which project radially relative to the bearing face at the end of the mould so as to retain the core by the abutment of its end face against said lugs. The latter can project internally under the action of springs or of the centrifugal force when the mould rotates. They are mounted in such manner that they are exposed to projections of liquid iron which occur when the latter sometimes is in excess in the pipe socket zone. Consequently, it is sometimes necessary to remove the pieces of excess iron which may block the locking device and this is a loss of time and slows down production. Further, the lug-type locking devices are connected to the mould. This arrangement does not lend itself well to a mechanical feeding of the cores.

The object of the invention is to provide for a centrifugal casting mould for casting pipes having a socket, a socket core support which ensures in a simple and effective manner the locking of said cores and is unexposed to the projections of iron and adaptable to a mechanical feeding of the cores.

According to the invention, the core support or yoke, mounted at the end of a swingable handling arm, for a centrifugal casting mould comprises in combination a cup for supporting and centering the core and extended by an outwardly divergent deflecting cone; a locking ring inserted with clearance in the cup coaxially of the latter; compressed air blowing means for blowing air between the locking ring and the end face of the recess for the ring in the cup, a handling stirrup mounted at its ends on the locking ring to be pivotable about an axis intersecting the axis of rotation of the mould, and a handling arm on the end of which the stirrup is mounted to be slightly pivotable about an axis perpendicular to the pivot axis of the stirrup on the locking ring.

Another object of the invention is to provide a centrifugal casting mould for casting pipes having a socket, said mould including a core support of the above-described type.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawings.

In the drawings:

Patented Nov. 26, 1968 FIG. 1 is a diagrammatic view, partly in section, of a mould according to the invention;

FIG. 2 is a partial end view taken along line 2--2 of FIG. 1, and

FIG. 3 is a detailed sectional view, on an enlarged scale, of the core support according to the invention.

In the embodiment shown in FIGS. 1 and 2, the invention is shown to be applied to a rotary mould M having a roughly honizontal axis X-X and intended for centrifugally casting a pipe T having a socket and composed for example of cast iron. This mould comprises two rolling rings 1 which cooperate with two pairs of support rollers 2 mounted between bearings 3. A motor 4 rotates the rollers 2 of one of said pairs of rollers. The assembly is mounted on a centrifugal casting machine which is represented diagrammatically by its casing C.

The mould M comprises at the end thereof adjacent the socket of the pipe T to be obtained (FIGS. 1 and 3), a divergent cavity 5 in the form of a tulip or bell which is enlarged at the entrance thereof in the form of two successive cylindrical recesses, namely recess or housing 6 for a core N which imparts the inner shape to the socket, and recess or housing 7 which is of greater diameter for supporting said core. The divergent cavity 5 is separated from the core recess 6 by a transverse face 8. The recess 7 is connected to the exterior by a divergent conical entrance portion 9 or countersinking.

The core N is for example of sand. It comprises near its end a flange 10 which acts as a print for the end face of the pipe and bears on the transverse face 8 located between the bell 5 and recess 6. The core is extended beyond the flange 10 by a cylindrical male support or bearing face 11.

The core or yoke support S according to the invention comprises three parts:

A rotary core support and centering cup.

A rotary cone for protecting against projection of iron, or deflecting cone.

A locking ring which is prevented from rotating and mounted on a handling stirrup carried by a swingable arm for placing in position or withdrawing the core support S.

This support S of the core N therefore comprises a cup 12 having the shape of a circular plate and an axis XX and a diameter slightly less than that of the recess 7. This cup has an axial bore or aperture 13 whose diameter corresponds to that of the diameter of the bearing face 11 for the core N. This bore 13 thus constitutes a centering support face for this core. The cup 12 comprises on one side an annular plane face 14 for urging the flange 10 of the core against the transverse face 8 of the mould. The face 14 corresponds to the face 8 of the mould and is inwardly defined by an inner recess 15.

The cup 12 is extended beyond the support face 13 by an outwardly divergent deflecting cone 16 which has an axis XX and is adapted to protect the locking means of the support S from projections or splashes of iron.

The cup 12 is provided with an annular recess or housing 17 having an axis XX on the side of the cup opposed to the face 14, that is, adjacent the deflecting cone 16. A locking ring 18 is inserted with clearance in the recess 17.

The locking ring 18 is provided with an annular groove 19 on its periphery in which groove is engaged the teat of at least one clamping screw 20 which is radially screwed into the wall of the cup 12 so as to interconnect the cup 12 and the locking ring 18 axially but not as concerns rotation, the end teat of each screw 20 extending into the interior of the annular recess 17. The groove 19 has a width exceeding the diameter of the teat or teatsso that there is a certain amount of axial play between the cup 12 and the locking ring 18.

This locking ring 18 is provided internally with an annular cavity 21 having an axis X-X. Communicating with this cavity 21 is the aperture of a connection element 22 located at the end of a flexible conduit 23 supplying compressed air. On its opposite face adjacent the end face of the recess 17, the ring 18 is provided with a number of blowing orifices 24 which are disposed on a circle and communicate with the cavity 21.

Preferably, a friction ring 25, having roughly the same diameter as the locking ring, is interposed between the latter and the recess 17 in the cup 12. This ring 25 can be of plastics material, such as red fibre, Teflon or of antifriction metallic material such as bronze or lead-antimoine alloys or of a combination of plastics materials and metallic materials.

As mentioned hereinbefore, the core support or yoke S is carried by a handling device. This will now be described with reference to FIGS. 1 and 2.

The locking ring 18 comprises a pair of ears 26 which are diametrically opposed. Mounted on these ears to pivot about a diametrical axis YY are the ends of a handling stirrup E. The stirrup E is itself pivotable through a few degrees at 27 on the end of a swingable handling arm B. The pivotal connection 27 of the stirrup E to the arm B has an axis ZZ which is perpendicular to the pivot axis of the stirrup E on the ears 26. The pivotal connection 27 is retained axially by a locking device of known type, for example pins 28 which engage with a slight clearance in apertures 29 formed in the pivot 27.

The pivotal connections of the stirrup E to the cars 26 of the ring 18 and to the pivot 27 of the arm B advantageously constitute in accordance with the invention a floating mounting of the support assembly S.

The swingable arm B is carried by a shaft D having an axis parallel to the axis X-X mounted outside the machine so as to be rotatable through a fraction of a revolution and movable axially in the known manner. For this purpose, it is mounted in the known manner in the extension of the piston rod of a jack V to which it is connected as concerns axial movement by a coupling A which allows it to rotate. The shaft D is driven in rotation a fraction of a revolution in the known manner for example by a transverse jack W which actuates a lever 30 connected to a sleeve 31 slidably keyed to the shaft D. The jacks V and W are fixed to the outside of the centrifugating machine.

This machine permits the introduction and withdrawal of the core N from the mould M and the swinging of the support S outside the axis of the mould (position of the arm B shown in dot-dash line in FIG. 2) so that the mould pipe T can then be withdrawn and the mould can receive a new core N.

This machine operates in the following manner:

When the mould has stopped rotating, the support S is withdrawn from the mould by the action of the jack V and swung through a fraction of a revolution by the action of the jack W so that a core N can be placed in position. This core is therefore introduced in the centering support or hearing face 13 of the support S until its flange is applied against the face 14 of the cup 12. Thereafter, the jacks W and V are actuated in succession so as to return the support S to the position in which it is coincident with the axis XX of the mould and insert the core N in the mould.

Owing to the floating mounting on the handling arm B (axial clearance between the clamping screws and the groove 19), the pivotal mounting of the stirrup E on the ears 26 of the ring 18 and the pivot 27, the support S is freely centered by its cup 12 in its housing or recess 7 in the mould. The support S tends to apply the flange 10 of the core against the transverse face 8 at the inner end of the recess 6. The core is held perfectly flat against the face 8 of the mould in the manner described hereinafter.

With the mould M still stationary, air is supplied at a pressure of at least 1 bar to the flexible conduit 23. This air is blown through the apertures 24 over the annular contact face between the friction ring 25 and the locking ring 18. A film or layer of compressed air is thus created between the two rings.

The friction ring 25 is thus thrust away from the locking ring 18 and flat against the inner end of the annular recess 17 in the cup 12. Consequently, the axial locking thrust of the ring 18, which is prevented from rotating, on the rotary cup 12 is exerted through the friction ring 25. In this way a perfect abutment of the core N against the face 8 of the mould is achieved. When the mould M is driven in rotation, the core N (which is urged against the mould) and its support S (cup 12 and deflecting cone 16) are driven in rotation at the same speed as the mould. The friction ring 25 also has a tendency to rotate owing to the fact that it is in contact with the inner end face of the annular recess 17 of the cup 12. On the other hand, owing to the compressed air between the locking ring 18 and friction ring 25 this locking ring is perfectly independent of the movement of rotation. The film of compressed air therefore permits a non-rotary member (ring 18) to exert a thrust on a rotary member (cup 12).

During the casting, when the molten iron reaches the socket region of the mould, it fills the space between the core N and the mould M.

If iron in excess is thrown out of the mould, the deflecting cone 16 prevents the centrifugal projections or splashes from reaching the locking ring 18. Thus, the support S is perfectly protected as concerns its locking means by the deflecting cone 16.

It will be observed moreover that owing to the cylindri cal core centering and support face 11, the face 13 of the cup 12 is protected from possible contact with the liquid iron and this avoids an excessive heating of the cup. Further, the escape of compressed air from the film of air along the walls of the annular recess 17 in the cup 12 helps to cool continuously the latter whose temperature during casting remains moderate.

Owing to the annular clearance between the ring 18 and the recess 17 and the floating mounting of the support S on the handling arm B by means of screws 20 engaged with clearance in the groove 19 of the cup, the pivotal connections of the cars 26 of the ring 18 and pivot 27 of the stirrup E, the cup 12 is constantly thrust flat against the core N, even if the mould M should rotate in a noncircular manner, that is, oscillates about its axis X-X.

Further, owing to the groove 19 in the cup 12 and the retaining screws 20 engaged with clearance in said groove, the cup 12 remains connected to the locking ring 18 when the arm B is shifted axially and swung round.

At the end of the casting operation the support S for the core is withdrawn and the arm B swung laterally so as to permit the withdrawal of the pipe T and the placing in position of a new core N on the cup 12.

Although a specific embodiment of the invention has been described, many modifications and changes may be made therein without departing from the scope of the invention as defined in the appended claims.

Thus, although the invention has been more particularly described in relation to the moulding of cast iron pipes, it is also applicable to the moulding of pipes having a socket and composed of plastics material, such as a thermosetting resin, or of a material having a cement base (concerte, asbestos-cement).

In this case the socket core can be of plastics, elastic or metallic material.

Further, instead of being in one piece with the cup 12, the deflecting cone 16 can be detachably secured to the latter.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. A core support for a centrifugal casting mould for casting a pipe having a socket, said support comprising in combination: a cup for supporting and centering the core and having an annular recess and extended by an outwardly divergent deflecting cone; a locking ring inserted with clearance in the recess in the cup coaxially of the latter; compressed air blowing means for blowing air between the locking ring and the inner end face of the recess in the cup, a handling stirnup mounted at its ends on the locking ring to be pivotable about an axis intersecting the axis of rotation of the mould, and a handling arm on the end of which the stirrup is mounted to be slightly pivotable about an axis perpendicular to the pivot axis of the stirrup on the locking ring.

2. A core support as claimed in claim 1, wherein the core comprises a male cylindrical support face and the cup comprises a corresponding female cylindrical support face in which said male support face is inserted and centered.

3. A core support as claimed in claim 1, wherein the cup comprises a plane transverse face which adjoins a flange of the core, said flange being applied against a transverse plane face on the mould by the axial thrust exerted by said plane transverse face of the cup.

4. A core support as claimed in claim 3, wherein the cup comprises, on the side thereof opposed to the face adjoining the flange of the core, an annular recess in which the locking ring is inserted with clearance.

5. A core support as claimed in claim 3, wherein blowing apertures extend through the locking ring and communicate with the face of the ring adjacent the inner end face of the recess of the cup in which the ring is inserted.

6. A core support as claimed in claim 1, wherein the locking ring is provided with a pair of diametrally opposed ears which are connected to the stirrup for pivotal movement about a diametral axis, the pivotal axis of the stirrup on the end of the swingable arm being perpendicular to said diametral axis.

7. A core support as claimed in claim 1, wherein the locking ring is provided with an annular groove and a screw having a retaining teat, said screw threadedly extending through the Wall of the cup surrounding said recess and projecting inwardly of the annular recess of the ring so as to engage with clearance said groove and thus axially interconnect said cup and said ring with play.

8. A core support as claimed in claim 1, wherein a riction ring is interposed between the locking ring and the cup at the inner end of the annular recess in the cup for the locking ring.

9. A mould and core for centrifugal casting combined with a core support comprising in combination: a cup for supporting and centering the core and having an annular recess and extended by an outwardly divergent deflected cone; locking ring inserted with clearance in the recess in the cup coaxially of the latter; compressed air blowing means for blowing air between the locking ring and the inner end face of the recess in the cup, a handling stirrup mounted at its end on the locking ring to be pivotable about an axis intersecting the axis of rotation of the mould, and a handling arm on the end of which the stirrup is mounted to be slightly pivotable about an axis perpendicular to the pivot axis of the stirrup on the locking ring.

References Cited UNITED STATES PATENTS 2,267,815 12/1941 Bush. 2,517,317 8/1950 Janco 164292 3,040,395 6/1962 Warkoczewski 164-302 X 3,074,130 1/1963 Wittmoser et al. 164-302 X 3,168,765 2/1965 Bernhardt 164-302 I. SPENCER OVERHOLSER, Primary Examiner.

EUGENE MAR, Assistant Examiner.

Claims

1. A CORE SUPPORT FOR A CENTRIFUGAL CASTING MOULD FOR CASTING A PIPE HAVING A SOCKET, SAID SUPPORT COMPRISING IN COMBINATION: A CUP FOR SUPPORTING AND CENTERING THE CORE AND HAVING AN ANNULAR RECESS AND EXTENDED BY AN OUTWARDLY DIVERGENT DEFLECTING CONE; A LOCKING RING INSERTED WITH CLEARANCE IN THE RECESS IN THE CUP COAXIALLY OF THE LATTER; COMPRESSED AIR BLOWING MEANS FOR BLOWING AIR BETWEEN THE LOCKING RING AND THE INNER END FACE OF THE RECESS IN THE CUP, A HANDLING STIRRUP MOUNTED AT ITS ENDS ON THE LOCKING RING TO BE PIVOTABLE ABOUT AN AXIS INTERSECTING THE AXIS OF ROTATION OF THE MOULD, AND A HANDLING ARM ON THE END OF WHICH THE STIRRUP IS MOUNTED TO BE SLIGHTLY PIVOTABLE ABOUT AN AXIS PERPENDICULAR TO THE PIVOT AXIS OF THE STIRRUP ON THE LOCKING RING.