US3635281A - Extractor for stripping pipes and other hollow parts from moulds and similar operations - Google Patents

Extractor for stripping pipes and other hollow parts from moulds and similar operations Download PDF

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Publication number
US3635281A
US3635281A US37086A US3635281DA US3635281A US 3635281 A US3635281 A US 3635281A US 37086 A US37086 A US 37086A US 3635281D A US3635281D A US 3635281DA US 3635281 A US3635281 A US 3635281A
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Prior art keywords
jaw
extractor
structures
axis
wall
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Expired - Lifetime
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US37086A
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English (en)
Inventor
Bernard Michel Comte
Jean-Marie Louis Phili Gareaux
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Pont a Mousson SA
Centre de Recherches de Pont a Mousson
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Pont a Mousson SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D13/00—Centrifugal casting; Casting by using centrifugal force
    • B22D13/10—Accessories for centrifugal casting apparatus, e.g. moulds, linings therefor, means for feeding molten metal, cleansing moulds, removing castings
    • B22D13/108—Removing of casting

Definitions

  • the present invention relates to an extractor for stripping hollow parts, and more particularly cast iron pipes and other tubular parts, from a mould of a centrifugal casting machine.
  • centrifugal casting machines afford a high rate of production and the extraction of the still-hot pipes from the mould must be carried out very rapidly and under absolutely safe conditions.
  • the extraction must also be automatic with no loss of time due to faulty extraction.
  • Known extractors comprise jaws, clamps or claws arranged around a geometric axis of symmetry and capable of being opened or spread apart from this axis so as to grip or clamp against the inner face of the wall of the pipe to be extracted.
  • the opening or separation of the jaws is effected by a mechanical control device having an axial rod moving in translation, or an eccentric, or a pivoted block.
  • the jaws are capable of rotating about their geometric axis of symmetry.
  • the object of the invention is to remedy these drawbacks and to provide an improved rotatable extractor which has great flexibility, is easily constructed and enables pipes having an unevenness on the surface or different inside diameters to be extractedin a certain manner with no need for adjustment.
  • the extractor according to the invention is of the type having a plurality of jaws carried by a jaw carrier, mounted for rotation about a fixed support having a geometric axis of symmetry, and capable of moving away from said axis in opposition to the action of resiliently yieldable return means, wherein there is fixed on the jaw carrier a device for separating the jaws on which the jaws bear individually under the action of said resiliently yieldable means and which is radially expansible, at least in the region of the point at which each jaw bears thereupon, under the action of a compressed fluid.
  • the jaws can therefore separate or spread apart in a symmetrical or in an asymmetrical manner, not as a function of the action of an axial symmetrical mechanical control device, but as a function of defects in the shape of the inner face of the wall of the part to be extracted so that these jaws perfectly adapt themselves to this face.
  • the jawspreading device is an expansible core.
  • this core is a hollow bulb having an elastic wall fixed at one end on a plate or end member of a cylindrical jawcarrying body which is rotatably mounted on the fixed axial support of the extractor, said fixed support being hollow so as to define a fluid conduit connected to a source of fluid under pressure.
  • the jaw-spreading device comprises as many radial piston and cylinder devices as there are jaws, the cylinders of these devices being arranged at the end of the rotatable jaw carrier and the ends of the cylinders communicating in parallel with a single conduit of fluid under pressure located inside said jaw carrier.
  • the forces exerted by the jaws on the inner face of the wall of the tubular product to be extracted can be very high, in particular for large pipe diameters, even when employing fluid under pressure of only a few bars, since the forces applied on the jaws are equal to the product of this'pressure multiplied by the section of the pistons, which section is much larger than the area of contact of the pistons and of the jaws, whence a multiplication of the force equal to the ratio between this section and this area; the section of the radial pistons can be provided as large as the available space allows for pipes of large diameters.
  • FIG. 1 is an assembly view of a centrifugal casting machine equipped with an extractor according to the invention
  • FIG. 2 is a longitudinal sectional view of this extractor
  • FIG. 3 is a diagrammatic view of the extractor engaged in an asymmetrical part to be extracted
  • FIG. 4 is a diagrammatic assembly view of a centrifugal casting machine equipped with another extractor according to the invention.
  • FIG. 5 is a longitudinal sectional view of this extractor on a scale larger than that of FIG. 4;
  • FIG. 6 is a partial sectional view taken along line 6-6 of FIG. 5, and
  • FIG. 7 is a partial sectional view, similar to FIG. 5, of the extractor in the operative condition of the latter.
  • FIG. 1 the invention is shown to be applied to a centrifugal pipe-casting machine.
  • This machine comprises, as known per se, a tiltable casting ladle A which pours the molten metal into a channel B.
  • the latter pours the metal into a shell or mould D carried by a carriage C which travels between the points a and b of a runway.
  • Movable in the axial extension of the mould and runway is an extractor E according to the invention.
  • the latter is carried by an extractor carriage F.
  • This movable carriage moves on a runway between the forward extreme point 0 and rear extreme point d.
  • the extractor E is secured to the carriage F by a rigid fixed axial support ll having an axis X-X and for example the general shape of a cylindrical sleeve.
  • This support thus defines an axial conduit 2 for supplying fluid under pressure, as compressed air.
  • the conduit 2 is enlarged at one end in the form of a screw-threaded chamber 3 for connection to piping (not shown) supplying compressed air.
  • a cylindrical jaw-carrying body 4 is rotatably mounted on the support ll through a conical rolling bearing 5 and a thrust ball bearing 6. Pivoted at one end at 7 to the jawcarrying body 4 are jaw structures or jaws 8 which are interconnected at their other ends by springs 9. These jaws 8 normally bear in a first position of rest against the outer face of the body 4.
  • a plate or end member 11 Fixed to the latter in a fluidtight manner, for example on a shoulder 12, is a fluid-actuable device comprising an expansible core in the form of a hollow elastic bulb 13.
  • This core is suitably constructed, for example in a composite manner with wall means comprising an inner wall 14 of rubber or other deformable material covered with a stratified heat-insulating protecting wall 15, for example of mineral wool.
  • a sealing element 16 is interposed between the end member 11 and a tubular extension portion 17 on the support l which opens into the interior or chamber defined by the wall means comprising the composite wall M, 15 and end member 11.
  • This core has normally an outside diameter not exceeding that of the jaw-carrying body 4. However, when it is inflated, the core 13 has a diameter exceeding that of the body 4.
  • the jaws 8 have such length that their ends opposed to the pivotal connections 7 bear on the core 13, at least when the core has started to expand if not when it is deflated.
  • the extractor according to the invention operates in the following manner:
  • the extractor E is introduced in the usual manner into the centrifugally cast pipe T in the mould. Air or other fluid under pressure is thereafter supplied to the inner chamber of the core 13 which is inflated. Its expansion results in the movement of portions of the wall means 14, 15 from inner positions toward outer positions and in the spreading apart or separation of the jaws which move from the first position 8, namely the closed or withdrawn position shown in full line, to a second or open position shown in dot-dash line in FIG. 2.
  • the extractor which is freely rotatable about the support 1, is driven in rotation by this pipe which is itself driven by the rotating mould D.
  • the pipe is therefore encountered and gripped without jerks and without creating sudden stresses in the end of the pipe.
  • the jaws 8 are capable of spreading apart either symmetrically with respect to the axis XX (FIG. 2) or asymmetrically (FIG. 3) and perfectly mate with the inner face of the wall of the pipe to be extracted and therefore perfectly grip this pipe so as to extract it in a sure manner.
  • the extracting force is proportional to the pressure of the fluid supplied.
  • the supply and discharge of air is automatically controlled.
  • This very simple and easily constructed device permits the extraction of pipes with no jerks and no risk of disengagement and at a very high rate which is in fact the rate of production of these pipes.
  • FIG. 4 carries identical reference characters for similar parts shown in FIG. 1.
  • the extractor E is connected to the carriage F by an axial rigid tubular support 4 having an axis XX and mounted to rotate freely at its rear end inside a support sleeve 1 through a rolling bearing 21 and a roller or ball thrust bearing 22 (FIG.
  • the tubular support 4 carries internally, at its front end, a fluid-actuable device comprising a collar 24 having a number, for example six, radial bores or apertures 24 evenly spaced apart and a radial piston 25 slidable in each of these bores 24.
  • a center distributor 26 Mounted on the axis of the collar 23 is acenter distributor 26 with which the ends of the bores 24 communicate and which put these bores in communication in parallel with an axial conduit 2" supplying fluid under pressure.
  • the cavity in the distributor 26 and the bores 24 constitute a chamber defined by wall means portions of which, namely the pistons 25, are independently movable between inner and outer positions when exposed to pressure of a fluid.
  • the conduit 2 is rotatable with the tubular support 4 and connected by a rotatable joint (not shown) to a fixed supply conduit disposed outside the zone shown by the drawing.
  • the tubular support 4 constitutes a jaw carrier. Pivoted to this support for pivotal movement about transverse axes 7 are the rear ends of longitudinal extracting levers 27 the number of which equals that of the radial pistons 25. These levers are in alignment with the various generatrices of the support 4 which intersect the axes of the pistons 25, each piston being supplied with one lever. These levers 27 can therefore undergo angular movements between a first or inner position and a second or outer position in radial planes containing said generatrices and the axes of the radial bores 24. They move in opposition to the action of opposing return springs 9 which are, for example, hooked to the levers 27 and to the axial conduit 2" and extend through the wall of the tubular support 4.
  • each lever 27 Pivoted to the free end of each lever 27 is an extracting jaw member 8 which is applied by the corresponding spring 9 against the radial pistons 25.
  • the jaw 8 and lever 27 constitute a jaw structure.
  • the ends of the pistons 25 are preferably crowned so as to afford a point contact with the levers 21.
  • This extractor operates in the following manner:
  • the extractor E After casting a pipe T, the extractor E is introduced inside the centrifugally cast pipe in the mould D.
  • the fluid under pressure is supplied by way of the axial conduit 2", the distributor 26 and the radial bores 24.
  • the pistons 25 spread apart and outwardly shift the jaws members 8" in opposition to the action of the springs 9.
  • Each jaw member 8 is applied against the wall of the pipe with a force which is proportional to the pressure of the fluid and to the section of the bore 24. This force is the same for all the jaw members 8 even if the extractor E is not perfectly on the axis of the mould or if the inner wall of the pipe T is not perfectly circular or has surface unevenness. Tire jaw membets 8 therefore grip the pipe perfectly so as to extract it in a sure manner.
  • the number of pistons 25 and corresponding jaw members 8 is not critical. The number is small for pipes of small diameter and great for pipes of large diameter. As already men tioned, the force applying each jaw member 8 against the pipe can be increased for a given pressure of fluid by increasing the section of the bores 24 and pistons 25.
  • the invention is applicable to the extraction of pipes of plastic materials, concrete, asbestos-cement or other organic or mineral materials, from their centrifugal casting moulds or shells. It is applicable to the extraction of partially solid moulded parts which have a hollow portron.
  • An extractor for extracting a tube or other hollow part having an inner face from a mould comprising a fixed support, a jaw carrier mounted on said fixed support, a plurality of jaw structures carried by said jaw carrier and arranged symmetrically about an axis, each jaw structure being movable away from said axis from a first position to a second position independently of the others of said jaw structures, a fluid-actuable device mounted on said jaw carrier and comprising wall means defining a chamber, portions of said wall means being respectively engageable with said jaw structures, each of said wall means portions being movable radially of said axis independently of the others of said portions of said wall means between an inner position in which the corresponding jaw structure is allowed to move to said first position and an outer position in which the corresponding jaw structure is in said second position, resiliently yieldable means combined with said jaw structures to bias said jaw structures toward said first positions, and means for supplying fluid under pressure to said chamber whereby said portions of said wall means are exposed to the pressure of said fluid and urged toward said outer positions
  • An extractor for extracting a tube or other hollow part having an inner face from a mould comprising a fixed support, a jaw carrier mounted on said fixed support, a plurality of jaw structures carried by said jaw carrier and arranged symmetrically about an axis, each jaw structure being movable away from said axis from a first position to a second position independently of the others of said jaw structures, a fluid-actuable device mounted on said jaw carrier and comprising a hollow bulb having a deformable elastic wall defining a chamber, portions of said bulb wall being respectively engageable with said jaw structures, said bulk being elastically expansible radially of said axis and each of said portions of said bulb wall being movable independently of the others of said portions of said bulb wall between an inner position corresponding to an unexpanded bulb in which the corresponding jaw structure is allowed to move to said first position and an outer position in which the corresponding jaw structure is in said second position, resiliently yieldable means combined with said jaw structures to bias said jaw structures toward said first positions, and a supply
  • each of said jaw structures has one end pivoted to said jaw carrier and another end freely movable and capable of bearing against said bulb.
  • An extractor for extracting a tube or other hollow part having an inner face from a mould comprising a fixed support, a jaw carrier mounted to rotate relative to said fixed support, a plurality of jaw structures carried by said jaw carrier and arranged symmetrically about an axis and capable of spreading away from said axis, a fluid-actuated device mounted on said jaw carrier and engageable with said jaw structures for spreading said jaw structures away from said axis, said device comprising a plurality of radially extending means each of which comprises a cylinder and an axially movable piston in the cylinder, there being as many piston and cylinder means as there are jaw structures, the cylinders of said means being arranged at the end of said jaw carrier and having ends communicating in parallel with a single conduit of fluid under pressure located inside said jaw carrier, said pistons having outer end portions engageable with said jaw structures for spreading said jaw structures, and resiliently yieldable means combined with said jaw structures to bias said jaw structures toward said axis and into individual bearing relation to said pistons.
  • each jaw structure comprises a lever pivoted to said jaw carrier in such manner as to be movable away from the latter in longitudinal radial planes containing the axis of said jaw carrier, and jaw members pivoted to said levers for direct engagement with said inner face.
  • each of said end portions of the pistons has a crowned bearing face in hearing relation to the corresponding lever.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extraction Or Liquid Replacement (AREA)
US37086A 1969-05-16 1970-05-14 Extractor for stripping pipes and other hollow parts from moulds and similar operations Expired - Lifetime US3635281A (en)

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FR6915848A FR2041650A5 (xx) 1969-05-16 1969-05-16

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FR (1) FR2041650A5 (xx)
YU (1) YU33086B (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3773447A (en) * 1972-02-01 1973-11-20 W Barratt Apparatus for producing cement sheets
US3778206A (en) * 1970-07-31 1973-12-11 W Barratt Apparatus for producing cement sheets
US5775837A (en) * 1996-07-03 1998-07-07 Schneider; Thomas W. Inflatable plugs for installing erosion control blocks

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1726672A (en) * 1928-01-14 1929-09-03 Us Cast Iron Pipe And Foundry Pipe-gripping mechanism
US1754106A (en) * 1928-01-17 1930-04-08 Centrifugal Castings Ltd Apparatus for extracting pipes and like cylindrical articles from the molds in which they are cast
US1776547A (en) * 1927-07-06 1930-09-23 Ferric Engineering Company Pipe-extracting apparatus
US3013835A (en) * 1959-04-01 1961-12-19 Leland F Blatt Power operated jaw assembly
US3131961A (en) * 1962-04-23 1964-05-05 Gen Tire & Rubber Co Hoisting devices
US3354942A (en) * 1965-10-06 1967-11-28 Gen Motors Corp Sprue extractor for molding machines
US3397735A (en) * 1965-10-23 1968-08-20 Shahmoon Ind Inc Pull and spray station for centrifugal casting machine
US3488692A (en) * 1967-02-08 1970-01-06 Aisin Seiki Transfer machine for die-cast products
US3522838A (en) * 1968-04-30 1970-08-04 Respond Inc Die casting extractor

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1776547A (en) * 1927-07-06 1930-09-23 Ferric Engineering Company Pipe-extracting apparatus
US1726672A (en) * 1928-01-14 1929-09-03 Us Cast Iron Pipe And Foundry Pipe-gripping mechanism
US1754106A (en) * 1928-01-17 1930-04-08 Centrifugal Castings Ltd Apparatus for extracting pipes and like cylindrical articles from the molds in which they are cast
US3013835A (en) * 1959-04-01 1961-12-19 Leland F Blatt Power operated jaw assembly
US3131961A (en) * 1962-04-23 1964-05-05 Gen Tire & Rubber Co Hoisting devices
US3354942A (en) * 1965-10-06 1967-11-28 Gen Motors Corp Sprue extractor for molding machines
US3397735A (en) * 1965-10-23 1968-08-20 Shahmoon Ind Inc Pull and spray station for centrifugal casting machine
US3488692A (en) * 1967-02-08 1970-01-06 Aisin Seiki Transfer machine for die-cast products
US3522838A (en) * 1968-04-30 1970-08-04 Respond Inc Die casting extractor

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3778206A (en) * 1970-07-31 1973-12-11 W Barratt Apparatus for producing cement sheets
US3773447A (en) * 1972-02-01 1973-11-20 W Barratt Apparatus for producing cement sheets
US5775837A (en) * 1996-07-03 1998-07-07 Schneider; Thomas W. Inflatable plugs for installing erosion control blocks

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Publication number Publication date
FR2041650A5 (xx) 1971-01-29
YU124370A (en) 1975-10-31
YU33086B (en) 1976-04-30

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