Explosion proof plastic electrical enclosure

Claim 2

In an explosion proof electrical enclosure comprising a box and a cover releasably attached to the box which box and cover have internal walls defining an internal opening for electrical wiring, said box and cover have mating faces at the juncture therebetween, the improvement comprising: said box and cover being mainly formed of plastic and each including a metal flange at the respective face and circumscribing said opening at the face, said flanges being in immediate juxtaposition when said cover is on said box, said flanges being formed of an erosion resistant metal.

Claim 3

In an explosion proof enclosure as set forth in claim 1, wherein said faces are at approximately right angles to the inner wall of the box and have inner and outer parts, said flanges are in juxtaposition to only the inner part of said faces with the plastic being exposed at the outer part of said faces, said outer part of the faces being substantially coplanar with the respective flanges.

Claim 4

In an explosion proof enclosure comprising a box and a cover releasably attached to the box which box and cover have internal walls defining an internal opening for electrical wiring, said box and cover have mating faces at the juncture therebetween, and for use with grounded metal conduit and an electrical component adapted to be mounted on the cover and having a metallic mounting member which is intended to be connected to ground, and having a portion of the box adapted to receive and engage said conduit and a portion of the cover adapted to receive and support said component, the improvement comprising: said box and cover being mainly formed of plastic and each including a metal flange at the respective face and circumscribing said opening at the face, said flanges being in immediate juxtaposition when said cover is on said box, said flanges being formed of an erosion resistant metal; said portion of the box including a first metallic member which is in electrical contact with said conduit when the conduit is in engagement with the box; said portion of the cover including a second metallic member which is in electrical contact with the mounting member when the component is mounted on the cover; first means electrically connecting the first metallic member and the metal flange of the box, and second means electrically connecting the second metallic member and the flange of the cover; said flanges being in contact with each other thereby forming an electrical connection therebetween.

Claim 5

In an explosion proof enclosure comprising a box and a cover releasably attached to the box which box and cover have internal walls defining an internal opening for electrical wiring, said box and cover have mating faces at the juncture therebetween, and for use with grounded metal conduit and an electrical component adapted to be mounted on the cover and having a metallic mounting member which is intended to be connected to ground, and having a portion of the box adapted to receive and engage said conduit and a portion of the cover adapted to receive and support said component, the improvement comprising: said box and cover being mainly formed of plastic and each including a metal flange at the respective face and circumscribing said opening at the face, said flanges being in immediate juxtaposition when said cover is on said box, said flanges being formed of an erosion resistant metal; said portion of the box including a first metallic member which is in electrical contact with said conduit when the conduit is in engagement with the box; said portion of the cover including a second metallic member which is in electrical contact with the mounting member when the component is mounted on the cover; first means electrically connecting the first metallic member and the metal flange of the box, and second means electrically connecting the second metallic member and the flange of the cover; said flanges being in contact with each other thereby forming an electrical connection therebetween.

Claim 6

In an explosion proof enclosure as set forth in claim 3, wherein the box flange has an integral portion which is in juxtaposition to part of the internal wall of the box, said flange portion being connected to said first metallic member and forming said first means; and the cover flange has an integral portion which is in juxtaposition to part of the internal wall of the cover, said cover flange portion forming said second metallic member and said second means.

Claim 7

In an explosion proof enclosure as set forth in claim 4, wherein said first metallic member is annular with internal threads and ridges on the exterior thereof, said first metallic member being an insert in said plastic.

Claim 8

In an explosion proof enclosure as set forth in claim 3, wherein said first metallic member is annular with internal threads and ridges on the exterior thereof, said first metallic member being an insert in said plastic.

Claim 9

In an explosion proof enclosure as set forth in Claim 6, wherein said faces are at approximately right angles to the inner wall of the box and have inner and outer parts, said flanges are in juxtaposition to only the inner part of said faces with the plastic being exposed at the outer part of said faces, said outer part of the faces being substantially coplanar with the respective flanges.

Claim 10

In an explosion proof enclosure comprising a box and a cover releasably attached to the box which box and cover have internal walls defining an internal opening for electrical wiring, said box and cover have mating faces at the juncture therebetween, said enclosure being rectangular and having four corners, said cover being attached to the box by screws and the enclosure being mounted by means of screws, the improvement comprising: said box and cover being mainly formed of plastic and each including a metal flange at the respective face and circumscribing said opening at the face, said flanges being in immediate juxtaposition when said cover is on said box, said flanges being formed of an erosion resistant metal; and a metallic stud in each of said corners of said box with a top end in juxtaposition to the box face and an opposite end in juxtaposition to the opposite side of the box, each of said ends being threaded to receive said screws.

Claim 11

In an explosion proof enclosure comprising a box and a cover releasably attached to the box which box and cover have internal walls defining an internal opening for electrical wiring, said box and cover have mating faces at the juncture therebetween, said enclosure being rectangular and having four corners, said cover being attached to the box by screws and the enclosure being mounted by means of screws, the improvement comprising: said box and cover being mainly formed of plastic and each including a metal flange at the respective face and circumscribing said opening at the face, said flanges being in immediate juxtaposition when said cover is on said box, said flanges being formed of an erosion resistant metal; and a metallic stud in each of said corners of said box with a top end in juxtaposition to the box face and an opposite end in juxtaposition to the opposite side of the box, each of said ends being threaded to receive said screws.

Claim 12

In an explosion proof enclosure as set forth in claim 8, wherein said faces are at approximately right angles to the inner wall of the box and have inner and outer parts, said flanges are in juxtaposition to only the inner part of said faces with the plastic being exposed at the outer part of said faces, said outer part of the faces being substantially coplanar with the respective flanges.