Pressure cooker interlock

Claim 2

In a pressure cooker including a receptacle and a cover, safety interlock apparatus comprising: (a) said receptacle and said cover having annular sealing surfaces disposed in juxtaposition; (b) interlocking lugs on said cover and receptacle, said cover being rotatable with respect to said receptacle in a first direction between a first position in which said lugs are disengaged and a second, fully locked position; (c) a resilient gasket disposed between said sealing surfaces, said gasket having upper and lower faces and comprising upper and lower inwardly extending, diverging leg portions with inner peripheral sealing lip portions, and said gasket further having space, radially extending ribs formed on at least one of said upper and lower faces; (d) said interlocking lugs being so constructed and arranged that in the second position of said cover, a first distance between said sealing surfaces is established such that pressure within said pressure cooker can force the leg portions apart with said sealing lip portions pressed into sealing engagement with said sealing surfaces to thereby permit pressure to build up within said cooker; and (e) means associated with at least selected ones of said lugs for reducing the distance between said sealing surfaces with the cover located between said first and second positions to a second distance at which at least one of said sealing surfaces engage said ribs of said gasket to compress said leg portions together and prevent a seal from forming between said lip portions and said sealing surfaces, and for preventing rotation of said cover toward said first position from said second position so long as the distance between said sealing surfaces is greater than said second distance.

Claim 3

The pressure cooker of claim 1 including said gasket having an outer peripheral portion with substantially parallel upper and lower faces and having an inner peripheral portion comprising upper and lower inwardly extending annular leg portions with upper and lower faces coextensive with said faces of said outer portion.

Claim 4

The pressure cooker of claim 2 wherein said leg portions of said gasket are connected to said outer portion by their connecting portions forming hinges which permit the leg portions to freely pivot without deforming the leg portions.

Claim 5

The pressure cooker of claim 2 wherein at least some of said ribs are formed between said hinges and said lip portions of said gasket.

Claim 6

The pressure cooker of claim 1 wherein said leg portions of said gasket have inner edges and facing surfaces, and wherein a peripheral part of each leg portion is removed in the area of the converging inner edge and facing surface to define a peripheral lip portion of gradually decreasing thickness which is more pliable than the remainder of said gasket in order to flex agaisnt said adjoining sealing surface.

Claim 7

The pressure cooker of claim 1 wherein said gasket comprises a body portion and the inwardly extending leg portions, and wherein said leg portions diverge such that the sealing lip portions are normally spaced apart further than the thickness of said body portion, and wherein said normal spacing is such that the sealing lip portions will engage said sealing surfaces as said surfaces move to said first distance apart.

Claim 8

The pressure cooker of claim 1 wherein said means associated with said lugs comprise said lugs on said receptacle each having a leading edge first encountered by said cover lugs upon rotation in said first direction, at least selected ones of said receptacle lugs having an axially extending body stop lug of short peripheral dimension at said leading edge which engages the adjoining surface of said cover lug until the cover reaches the second position, the axial length of said body stop lugs being sufficient to prevent said seal from forming said body stop lugs extending behind said cover lugs with said cover in said second position to prevent reverse rotation of said cover so long as pressure is present in said pressure cooker.

Claim 9

In a pressure cooker including a receptacle and a cover, safety interlock apparatus comprising: (a) said receptacle and said cover having annular sealing surfaces disposed in juxtaposition; (b) interlocking lugs on said cover and receptacle, said cover being rotatable with respect to said receptacle in a first direction between a first position in which said lugs are disengaged and a second, interlocked position; (c) an annular gasket with oppositely disposed faces positioned between said sealing surfaces, said gasket comprising upper and lower inwardly extending diverging leg portions with inner peripheral sealing portions, and said gasket further having spaced bosses on at least one of said faces; (d) said interlocking lugs being so constructed and arranged that in the second position of said cover, a first distance between said sealing surfaces is established such that pressure within said pressure cooker can force the leg portions apart with said sealing portions pressed into sealing engagement with said sealing surfaces to thereby permit pressure to build up within said cooker; and (e) means associated with at least selected ones of said lugs for reducing the distance between said sealing surfaces with the cover located between said first and second positions to a second distance at which at least one of said sealing surfaces engages said bosses on said gasket to prevent a seal from forming between at least one of said sealing portions and said associated sealing surface, and for preventing rotation of said cover toward said first position from said second position so long as the distance between said sealing surfaces is greater than said second distance.

Claim 10

In a pressure cooker including a receptacle and a cover, safety interlock apparatus comprising: (a) said receptacle and said cover having annular sealing surfaces disposed in juxtaposition; (b) interlocking lugs on said cover and receptacle, said cover being rotatable with respect to said receptacle in a first direction between a first position in which said lugs are disengaged and a second, interlocked position; (c) an annular gasket with oppositely disposed faces positioned between said sealing surfaces, said gasket comprising upper and lower inwardly extending diverging leg portions with inner peripheral sealing portions, and said gasket further having spaced bosses on at least one of said faces; (d) said interlocking lugs being so constructed and arranged that in the second position of said cover, a first distance between said sealing surfaces is established such that pressure within said pressure cooker can force the leg portions apart with said sealing portions pressed into sealing engagement with said sealing surfaces to thereby permit pressure to build up within said cooker; and (e) means associated with at least selected ones of said lugs for reducing the distance between said sealing surfaces with the cover located between said first and second positions to a second distance at which at least one of said sealing surfaces engages said bosses on said gasket to prevent a seal from forming between at least one of said sealing portions and said associated sealing surface, and for preventing rotation of said cover toward said first position from said second position so long as the distance between said sealing surfaces is greater than said second distance.

Claim 11

The pressure cooker of claim 8 wherein said gasket comprises an integral, resilient member which is symmetrical, having said bosses formed on both said faces.

Claim 12

The pressure cooker of claim 9 wherein said receptacle has a radial flange with the said annular sealing surface thereon facing said sealing surface of said cover, and with said lugs being on the periphery thereof, wherein said cover has a depending skirt surrounding the receptacle flange with inwardly projecting lugs formed on said skirt for interlocking engagement with said receptacle lugs, and wherein said gasket is disposed between said sealing surfaces with said outer peripheral portion thereof engaging said skirt.

Claim 13

The pressure cooker of claim 9 wherein axial grooves are formed in an edge of a peripheral portion of said gasket facing said skirt to vent trapped air or steam and wherein said bosses are in the form of radially extending ribs which cooperate with said sealing surfaces to hold said sealing portions away from said sealing surfaces during movements of said cover between said first and second positions.

Claim 14

In a pressure cooker including a receptacle and a cover, safety interlock apparatus comprising: (a) said receptacle having an annular sealing surface, and said cover having an annular sealig surface disposed in juxtaposition to said sealing surface on said receptacle; (b) interlocking lugs on said cover and receptacle, said cover being rotatable with respect to said recpetacle in a first direction between a first position in which said lugs are disengaged and a second position in which adjoining surfaces of said lugs are fully aligned, and means for preventing rotation in said first direction beyond said second position; (c) a resilient gasket disposed between said sealing surfaces, said gasket having a body portion and an inner peripheral portion comprising upper and lower inwardly extending annular leg portions with upper and lower faces and inner peripheral lip portions, said gasket being formed with said leg portions diverging, and said gasket further having spaced, radially extending ribs formed on at least one of said upper and lower faces; (d) said interlocking lugs being so constructed and arranged that in the second position of said cover, the distance between said sealing surfaces is such that pressure within said pressure cooker can force the leg portions apart with said lip portions pressed into sealing engagement with said sealing surfaces to thereby permit pressure to build up within said cooker; and (e) said lugs on said receptacle each having a a leading edge first encountered by said cover lugs upon rotation in said first direction, at least selected ones of said receptacle lugs having an axially extending body stop lug of short peripheral dimension at said leading edge which engages the adjoining surface of said cover lug until the cover reaches the second position, the axial length of said body stop lugs being such that with the cover located between said first and said second positions at least one of said sealing surfaces engage said ribs on said gasket to compress said leg portions together and prevent a seal from forming between said gasket and said sealing surfaces, and in said second position extend behind said cover lugs to prevent reverse rotation thereof while pressure exists within the pressure cooker.

Claim 15

In a pressure cooker including a receptacle and a cover, safety interlock apparatus comprising: (a) said receptacle having an annular sealing surface, and said cover having an annular sealig surface disposed in juxtaposition to said sealing surface on said receptacle; (b) interlocking lugs on said cover and receptacle, said cover being rotatable with respect to said recpetacle in a first direction between a first position in which said lugs are disengaged and a second position in which adjoining surfaces of said lugs are fully aligned, and means for preventing rotation in said first direction beyond said second position; (c) a resilient gasket disposed between said sealing surfaces, said gasket having a body portion and an inner peripheral portion comprising upper and lower inwardly extending annular leg portions with upper and lower faces and inner peripheral lip portions, said gasket being formed with said leg portions diverging, and said gasket further having spaced, radially extending ribs formed on at least one of said upper and lower faces; (d) said interlocking lugs being so constructed and arranged that in the second position of said cover, the distance between said sealing surfaces is such that pressure within said pressure cooker can force the leg portions apart with said lip portions pressed into sealing engagement with said sealing surfaces to thereby permit pressure to build up within said cooker; and (e) said lugs on said receptacle each having a a leading edge first encountered by said cover lugs upon rotation in said first direction, at least selected ones of said receptacle lugs having an axially extending body stop lug of short peripheral dimension at said leading edge which engages the adjoining surface of said cover lug until the cover reaches the second position, the axial length of said body stop lugs being such that with the cover located between said first and said second positions at least one of said sealing surfaces engage said ribs on said gasket to compress said leg portions together and prevent a seal from forming between said gasket and said sealing surfaces, and in said second position extend behind said cover lugs to prevent reverse rotation thereof while pressure exists within the pressure cooker.

Claim 16

A pressure cooker comprising, in combination: (a) a receptacle having a flat annular sealing surface; (b) a cover having a corresponding flat annular sealing surface; (c) a resilient gasket interposed between said surfaces, said gasket having spaced inwardly extending, annular sealig portions configured to form a seal against said surfaces when they are spaced by a first distance, and including means to prevent formation of such a seal when said surfaces are spaced by a second, smaller distance; (d) said cover and receptacle having lugs which interlock upon relative roatation thereof to intially establish said second distance; and (e) means associated with at least selected ones of said lugs for establishing said first distance when the lugs are fully interlocked and for preventing reverse relative rotation of said cover and receptacle from said fully interlocked position so long as a pressurized condition exists in said pressure cooker.

Claim 17

A pressure cooker comprising, in combination: (a) a receptacle having a flat annular sealing surface; (b) a cover having a corresponding flat annular sealing surface; (c) a resilient gasket interposed between said surfaces, said gasket having spaced inwardly extending, annular sealig portions configured to form a seal against said surfaces when they are spaced by a first distance, and including means to prevent formation of such a seal when said surfaces are spaced by a second, smaller distance; (d) said cover and receptacle having lugs which interlock upon relative roatation thereof to intially establish said second distance; and (e) means associated with at least selected ones of said lugs for establishing said first distance when the lugs are fully interlocked and for preventing reverse relative rotation of said cover and receptacle from said fully interlocked position so long as a pressurized condition exists in said pressure cooker.

Claim 18

The pressure cooker of claim 13 wherein said means to prevent formation of a seal comprises spaced bosses on said gasket facing at least one of said sealing surfaces whereby when said surfaces are spaced by said second distance the bosses engage said surface to hold at least one of said sealing portions away from its associated surface.

Claim 19

A resilient, flexible gasket for a pressure cooker, said gasket being annular about an axis and having axially opposite faces, comprising: (a) a circumferential body portion; (b) a pair of radially inwardly extending circumferential leg portions which diverge axially to terminate in inwardly peripehral sealing portions; (c) said gasket being configured to provide hinge means between said leg portions and said body portion whereby said leg portions can be freely pivoted toward each other; and (d) a plurality of peripherally spaced bosses extending axially from at least one of said faces, said bosses extending discontinuously across said leg portions and said body portion.

Claim 20

A resilient, flexible gasket for a pressure cooker, said gasket being annular about an axis and having axially opposite faces, comprising: (a) a circumferential body portion; (b) a pair of radially inwardly extending circumferential leg portions which diverge axially to terminate in inwardly peripehral sealing portions; (c) said gasket being configured to provide hinge means between said leg portions and said body portion whereby said leg portions can be freely pivoted toward each other; and (d) a plurality of peripherally spaced bosses extending axially from at least one of said faces, said bosses extending discontinuously across said leg portions and said body portion.

Claim 21

A resilient, flexible gasket for a pressure cooker, said gasket being annular about an axis and having axially opposite faces, comprising: (a) a circumferential body portion; (b) a pair of radially inwardly extending circumferential leg portions which diverge axially to terminate in inwardly peripheral sealing portions; (c) said gasket being configured to provide hinge means between said leg portions and said body portion whereby said leg portions can be freely pivoted toward each other; (d) a plurality of peripherally spaced bosses extending axially from at least one of said faces; and (e) said gasket being Y-shaped in cross section, whereby separate hinge means are provided between said body portion and said leg portions.

Claim 22

A resilient, flexible gasket for a pressure cooker, said gasket being annular about an axis and having axially opposite faces, comprising: (a) a circumferential body portion; (b) a pair of radially inwardly extending circumferential leg portions which diverge axially to terminate in inwardly peripheral sealing portions; (c) said gasket being configured to provide hinge means between said leg portions and said body portion whereby said leg portions can be freely pivoted toward each other; (d) a plurality of peripherally spaced bosses extending axially from at least one of said faces; and (e) said gasket being Y-shaped in cross section, whereby separate hinge means are provided between said body portion and said leg portions.

Claim 23

A resilient, flexible gasket for a pressure cooker, said gasket being annular about an axis and having axially opposite faces, comprising: (a) a circumferential body portion; (b) a pair of radially inwardly extending circumferential leg portions which diverge axially to terminate in inwardly peripheral sealing portions; (c) said gasket being configured to provide hinge means between said leg portions and said body portion whereby said leg portions can be freely pivoted toward each other; (d) a plurality of peripherally spaced bosses extending axially from at least one of said faces; and (e) said gasket being W-shaped in cross section, and said body portion comprising a hinge connecting said leg portions.

Claim 24

A resilient, flexible gasket for a pressure cooker, said gasket being annular about an axis and having axially opposite faces, comprising: (a) a circumferential body portion; (b) a pair of radially inwardly extending circumferential leg portions which diverge axially to terminate in inwardly peripheral sealing portions; (c) said gasket being configured to provide hinge means between said leg portions and said body portion whereby said leg portions can be freely pivoted toward each other; (d) a plurality of peripherally spaced bosses extending axially from at least one of said faces; and (e) said gasket being W-shaped in cross section, and said body portion comprising a hinge connecting said leg portions.