Runnerless mold for automated injection-molding of thermoset materials

Claim 2

In a mold of the character indicated, a first mold-body element having a mold cavity open to one side thereof, a seconD mold-body element selectively movable into adjacency with said side to open and close the cavity, said second body element having an injection port communicating with the cavity when the mold is closed, a third mold-body element including injectionsupply passage means extending into and substantially through said port, thermal-insulation means between said second and third body elements, heating means for said first and second body elements for establishing thermoset-curing conditions therein, and cooling means in said third body element for establishing noncuring conditions for material in said passage means, that part of said passage means which extends into said port comprising a head having a central passage for conduct of injected material directly to the mold cavity, said head having a further passage independent of and substantially surrounding the central passage and forming part of said cooling means, said further passage extending in an undulating course that is both generally axial and generally circumferential with respect to the central passage.

Claim 3

The mold of claim 1 wherein the undulating course of said further passage extends substantially through the port in said second body element.

Claim 4

In a mold of the character indicated, a first mold-body element having a mold cavity open to one side thereof, a second mold-body element selectively movable into adjacency with said side to open and close the cavity, said second body element having an injection port communicating with the cavity when the mold is closed, a third mold-body element including injection-supply passage means extending into and substantially through said port, thermal-insulation means between said second and third body elements, heating means for said first and second body elements for establishing thermoset-curing conditions therein, and cooling means in said third body element for establishing noncuring conditions for material in said passage means, that part of said passage means which extends into said port comprising a head having a central passage for conduct of injected material directly to the mold cavity, said head having a further passage independent of and substantially surrounding the central passage and forming part of said cooling means, said head being generally conical about the central passage and said port being relatively constricted at the surface of said second body element which is adjacent the mold cavity, said head having limited piloting engagement with said second body element only at the constricted end of said port.

Claim 5

In a mold of the character indicated, a first mold-body element having a mold cavity open to one side thereof, a second mold-body element selectively movable into adjacency with said side to open and close the cavity, said second body element having an injection port communicating with the cavity when the mold is closed, a third mold-body element including injection-supply passage means extending into and substantially through said port, thermal-insulation means between said second and third body elements, heating means for said first and second body elements for establishing thermoset-curing conditions therein, and cooling means in said third body element for establishing noncuring conditions for material in said passage means, that part of said passage means which extends into said port comprising a head having a central passage for conduct of injected material directly to the mold cavity, said head having a further passage independent of and substantially surrounding the central passage and forming part of said cooling means, said head being generally conical about the central passage and said port being relatively constricted at the surface of said second body element which is adjacent the mold cavity, said head having limited piloting engagement with said second body element only at the constricted end of said port.

Claim 6

The mold of claim 3, wherein said head includes a radially outward flange at the base of its generally conical shape and wherein said third body element is locally concave to receive and locate said flange, and means clamping into unit-handling relation said second and third body elements and said thermal-isolation means.

Claim 7

A cold-runner thermoset mold, comprising, a first mold-body plate element having parallel front and back surfaces with plural mold cavities open to said front surface, a second mold-body plate element having parallel front and back surfaces and a separate injection port communicating with each cavity when said front surfaces are juxtaposed, means including guide means coacting between said body elements for selectively placing said body elements in and out of juxtaposed relation for opening and closing the mold cavity, a third mold-body plate element having parallel front and back surfaces, a layer of thermal insulation having parallel front and back surfaces and located between otherwise adjacent back surfaces of said second and third body elements, said plate elements and said layer having substantially coextensive overlapped areas, means securing said second and third body elements to each other and against opposite sides of said insulation layer, said third body element including injection-supply passage means including a separate secondary sprue extending into and substantially through each said port, separatE thermodynamic supply means for each of said body elements, the thermodynamic supply to said first and second body elements being at such level as to establish thermoset-curing conditions therein, the thermodynamic supply to said third body element being at such level as to establish noncuring conditions for thermoset material in said third body element, and a single sprue and runner system serving said secondary sprues.

Claim 8

A cold-runner thermoset mold, comprising, a first mold-body plate element having parallel front and back surfaces with plural mold cavities open to said front surface, a second mold-body plate element having parallel front and back surfaces and a separate injection port communicating with each cavity when said front surfaces are juxtaposed, means including guide means coacting between said body elements for selectively placing said body elements in and out of juxtaposed relation for opening and closing the mold cavity, a third mold-body plate element having parallel front and back surfaces, a layer of thermal insulation having parallel front and back surfaces and located between otherwise adjacent back surfaces of said second and third body elements, said plate elements and said layer having substantially coextensive overlapped areas, means securing said second and third body elements to each other and against opposite sides of said insulation layer, said third body element including injection-supply passage means including a separate secondary sprue extending into and substantially through each said port, separatE thermodynamic supply means for each of said body elements, the thermodynamic supply to said first and second body elements being at such level as to establish thermoset-curing conditions therein, the thermodynamic supply to said third body element being at such level as to establish noncuring conditions for thermoset material in said third body element, and a single sprue and runner system serving said secondary sprues.

Claim 9

The mold of claim 5, and including a fourth body element having parallel front and back surfaces one of which is secured to the otherwise exposed surface of said third body element, said sprue and runner system comprising a sprue passage in said fourth body element and runner passages at the interface between said third and fourth body elements.

Claim 10

The mold of claim 6, in which said fourth body element includes thermodynamic-supply means at such level as to establish noncuring conditions for material in said fourth body element.

Claim 11

The mold of claim 5, in which said respective thermodynamic-supply means comprise separate heat-supply means to each of said first and second plate elements and separate cooling-supply means to said third plate element.

Claim 12

A demountable cold-runner mold established by a single stack of flat plates, comprising a first pair of mold-cavity plates, a second pair of runner-manifold plates, and a layer of thermal insulation with parallel front and back surfaces spacing said first pair from said second pair; said first pair having plural mold cavities defined at the adjacent surfaces of the plates thereof, the first-pair plate adjacent said insulation layer having a separate injection port at each mold-cavity location, said insulation layer having an aperture in register with each of said ports; said second pair having a runner-groove system defined at the adjacent surfaces of the plates thereof, the second-pair plate adjacent said insulation layer having separate injection ports in register with corresponding ports and apertures of said layer and first pair of separately communicating with said runner-groove system, the other second-pair plate having primary sprue means communicating with said runner-groove system, and plural secondary-sprue means carried by said first-mentioned mentioned second-pair plate and projecting through said layer and ports into discharging adjacency with the respective mold cavities; heating means for each of the plates of said first pair, and cooling means for each of the plates of said second pair.

Claim 13

A demountable cold-runner mold established by a single stack of flat plates, comprising a first pair of mold-cavity plates, a second pair of runner-manifold plates, and a layer of thermal insulation with parallel front and back surfaces spacing said first pair from said second pair; said first pair having plural mold cavities defined at the adjacent surfaces of the plates thereof, the first-pair plate adjacent said insulation layer having a separate injection port at each mold-cavity location, said insulation layer having an aperture in register with each of said ports; said second pair having a runner-groove system defined at the adjacent surfaces of the plates thereof, the second-pair plate adjacent said insulation layer having separate injection ports in register with corresponding ports and apertures of said layer and first pair of separately communicating with said runner-groove system, the other second-pair plate having primary sprue means communicating with said runner-groove system, and plural secondary-sprue means carried by said first-mentioned mentioned second-pair plate and projecting through said layer and ports into discharging adjacency with the respective mold cavities; heating means for each of the plates of said first pair, and cooling means for each of the plates of said second pair.

Claim 14

A mold according to claim 9, in which said cooling means includes a liquid-coolant system.

Claim 15

A mold according to claim 9, in which said cooling means includes cooling means for said secondary-sprue means.

Claim 16

A mold according to claim 11, in which said secondary-sprue means comprises, at each port location, a centrally apertured body mounted on the first-mentioned plate of said second pair and positioned in clearance relation with the associated port.

Claim 17

A mold according to claim 12, in which the secondary-sprue cooling means comprises a liquid-coolant circulating system around the central sprue aperture and substantially overlapping the axial extent thereof.