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US3836306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transfer molding apparatus
Assignee: Uniroyal GmbH
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Filing: 1973-07-16
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Granted: 1974-09-17
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Expires: 1993-07-16
Abstract
Abstract Apparatus for molding elastomeric stock, comprising an apertured, heat-resistant, flexible, insulation plate arranged between a heated mold and the discharge portion of an elastomeric stock injection unit such that a mold cavity is aligned with an array of apertures in the insulation plate which intercommunicate the mold cavity with an internal discharge chamber in the injection unit. A mold cavity cover is carried by the insulation plate and confronts the mold cavity, the cover and upper portion of the cavity when juxtaposed defining a constriction therebetween. When the mold and injection unit are moved relative to one another such that each presses against the other through the intermediary of the insulation plate, there is effected expulsion and transferring of a portion of elastomeric stock from the injection unit into the mold cavity to be cured, an excess portion of elastomeric stock remaining in the injection unit being prevented from undergoing curing by means of the presence of the insulation plate. The constriction between the cover and the upper portion of the cavity generates a score line in the cured transferred portion of stock along which scrap cured in the cavity may be separated from the cured product.
Inventors
- 👤 L Pasch
- 👤 H Wagemann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:56
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/02; B29C2045/027; Y; Y10; Y10S; Y10S425/00; Y10S425/051; Y10S425/228
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
343 words
Apparatus for molding elastomeric stock, said apparatus comprising: a mold provided with at least one mold cavity for shaping and curing elastomeric stock in the form of said cavity; an elastomeric stock injection unit having a chamber in which elastomeric stock is disposable and can be subjected to pressure for transfer from said chamber; a heat-resistant, flexible insulation plate positioned intermediate said mold and said injection unit, said insulation plate including flat, opposed, side faces and a fixed array of apertures therethrough for intercommunicating said injection unit with said mold cavity; a mold cavity cover carried by said insulation plate and confronting said mold cavity, said cover having an edge which bridges said array of apertures with one another, said mold cavity having an upper open portion for receiving said cover, said upper open portion and said edge when juxtaposed defining a constriction intercommunicating said cavity with said apertures; means for heating said mold; and means for moving said mold and said injection unit relative to one another in such a manner that said mold and said injection unit are pressed against the opposite side faces of said insulation plate, and said cover projects into said upper open portion of said cavity to define said constriction; whereby upon exertion of pressure in said chamber against said elastomeric stock a portion of said stock will be expelled from said chamber and concurrently transferred through each of said apertures, through said constriction and into said cavity, said insulation plate serving to thermally insulate a remaining portion of excess elastomeric stock in said chamber from said heated mold, without separation of said mold or said injection unit from said insulation plate or relaxation of said fluid pressure, in order to prevent the curing of said remaining portion of stock with the curing of said transferred portion of stock, said constriction generating a score line in said cured transferred portion of stock along which cured elastomeric scrap formed in said upper open portion may be separated from cured elastomeric product formed in the remainder of said cavity.
Claim 2
Dependent Claim
343 words
Apparatus for molding elastomeric stock, said apparatus comprising: a mold provided with at least one mold cavity for shaping and curing elastomeric stock in the form of said cavity; an elastomeric stock injection unit having a chamber in which elastomeric stock is disposable and can be subjected to pressure for transfer from said chamber; a heat-resistant, flexible insulation plate positioned intermediate said mold and said injection unit, said insulation plate including flat, opposed, side faces and a fixed array of apertures therethrough for intercommunicating said injection unit with said mold cavity; a mold cavity cover carried by said insulation plate and confronting said mold cavity, said cover having an edge which bridges said array of apertures with one another, said mold cavity having an upper open portion for receiving said cover, said upper open portion and said edge when juxtaposed defining a constriction intercommunicating said cavity with said apertures; means for heating said mold; and means for moving said mold and said injection unit relative to one another in such a manner that said mold and said injection unit are pressed against the opposite side faces of said insulation plate, and said cover projects into said upper open portion of said cavity to define said constriction; whereby upon exertion of pressure in said chamber against said elastomeric stock a portion of said stock will be expelled from said chamber and concurrently transferred through each of said apertures, through said constriction and into said cavity, said insulation plate serving to thermally insulate a remaining portion of excess elastomeric stock in said chamber from said heated mold, without separation of said mold or said injection unit from said insulation plate or relaxation of said fluid pressure, in order to prevent the curing of said remaining portion of stock with the curing of said transferred portion of stock, said constriction generating a score line in said cured transferred portion of stock along which cured elastomeric scrap formed in said upper open portion may be separated from cured elastomeric product formed in the remainder of said cavity.
Claim 3
Dependent Claim
74 words
Apparatus as claimed in claim 1, wherein said mold includes a core, and a plurality of annular plates superposed upon one another and defining cooperatively with said core an annular clearance which constitutes said mold cavity, said core including a free end portion, said cover having an extent adapted to overlie said annular clearance and an enlarged opening complementing the cross-section of, and adapted to closely surround, said free end portion of said core.
Claim 4
Dependent Claim
16 words
Apparatus as claimed in claim 2, wherein said cover is fixedly secured to said insulation plate.
Claim 5
Dependent Claim
17 words
Apparatus as claimed in claim 2, wherein said cover is movable axially relative to said insulation plate.
Claim 6
Dependent Claim
27 words
Apparatus as claimed in claim 4, including resilient means interposed between said cover and said insulation plate for separating said cover and insulation plate from one another.
Claim 7
Dependent Claim
16 words
Apparatus as claimed in claim 5, wherein said resilient means includes at least one compression spring.
Claim 8
Dependent Claim
49 words
Apparatus as claimed in claim 2, wherein said mold includes a plurality of apertured retainer plates superposed upon one another for confining corresponding ones of said annular plates, said annular plates being insertable into said retainer plates and movable locally relative to one another and relative to said core.
Claim 9
Dependent Claim
118 words
Apparatus as claimed in claim 7, wherein said annular plates and said core are associated with one another as an insert group for defining said mold cavity, and including further cores and annular plates associated with one another as further insert groups for defining further mold cavities, said retainer plates each including a plurality of apertures coaxially alinged with corresponding apertures in the others of said retainer plates for confining corresponding ones of said further insert groups, said insulation plate including further mold cavity covers aligned coaxially with corresponding ones of said further insert groups and operatively associated with the latter in a manner similar to that of the first said cover with the first said insert group.
Claim 10
Dependent Claim
23 words
Apparatus as claimed in claim 2, wherein said edge of said cover is substantially tangentially associated with said apertures in said insulation plate.
Claim 11
Dependent Claim
41 words
Apparatus as claimed in claim 9, wherein said cover has a substantially annular extent defined by an inner edge and an outer edge, said outer edge constituting said edge which is substantially tangentially associated with said apertures in said insulation plate.
Claim 12
Dependent Claim
41 words
Apparatus as claimed in claim 9, wherein said cover has a substantially annular extent defined by an inner edge and an outer edge, said inner edge constituting said edge which is substantially tangentially associated with said apertures in said insulation plate.
Claim 13
Dependent Claim
82 words
Apparatus as claimed in claim 2, wherein said injection unit includes a stationary piston and a cylinder axially movable relative thereto, said mold being supported for axial movement relative to said piston, such that said mold is movable into engagement with said cylinder and is then effective to move the latter relative to said piston to reduce the axial extent of said chamber, thereby to cause a portion of said elastomeric stock to be injected from said chamber into said mold cavity.
Claim 14
Dependent Claim
24 words
Apparatus as claimed in claim 2, wherein said insulation plate has a thermal-conductive capacity which is substantially less than the thermal-conductive capacity of iron.
Claim 15
Dependent Claim
21 words
Apparatus as claimed in claim 13, wherein the thermal conductivity of said insulation plate is in the range of 0.05-0.5 kcal/m/hr./*K.
Claim 16
Dependent Claim
25 words
Apparatus as claimed in claim 2, wherein said insulation plate has a compression resistance in the range of 200-2,000 kg./cm.2 at temperatures between 180*-200* C.
Claim 17
Dependent Claim
20 words
Apparatus as claimed in claim 2, wherein said insulation plate is constituted of an asbestos fiber and thErmoset resin mixture.
Claim 18
Dependent Claim
13 words
Apparatus as claimed in claim 16, wherein said thermoset resin comprises phenol resin.
Claim 19
Dependent Claim
69 words
Apparatus as claimed in claim 2, wherein said insulation plate includes, on the side face thereof which confronts and contacts said mold, a thin layer of hardenable, flexible material which undergoes increasing hardening when subjected to the heat and pressure of said heated mold, said layer having on the surface thereof facing said mold a profile complementary to the profile of the surface of said mold in contact therewith.
Claim 20
Dependent Claim
20 words
Apparatus as claimed in claim 18, wherein said thin layer is constituted of an asbestos fiber and thermoset resin mixture.
Claim 21
Dependent Claim
17 words
Apparatus as claimed in claim 19, wherein said thermoset resin of said thin layer comprises phenol resin.
Claim 22
Dependent Claim
77 words
Apparatus as claimed in claim 2, wherein said insulation plate has a thickness sufficient to maintain a temperature gradient thereacross such that, when the side face thereof which confronts said mold is at the curing temperature for said elastomeric stock in said mold cavity, the temperature on the opposite side face of said insulation plate which confronts said chamber remains at a temperature insufficient to cause the excess elastomeric stock remaining in said chamber to become cured.
Claim 23
Dependent Claim
41 words
Apparatus as claimed in claim 2, including respective annular insets disposed in said apertures of said insulation plate, said annular insets being constituted of a material having an adhesion resistance to said elastomeric stock greater than that of said insulation plate.
Claim 24
Dependent Claim
21 words
Apparatus as claimed in claim 22, wherein said annular insets are constituted at least in part of polytetrafluoroethylene or like material.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |