Electrical bushing assembly

Claim 2

A bushing assembly for connecting a load circuit to electrical apparatus within a casing, said bushing assembly comprising an elongated conducting member having a cylindrical central portion, an insulating bushing molded about the cylindrical central portion and receivable in an opening in a wall of the casing, the conducting member having inner and outer end portions extending axially away from the bushing from respective opposite ends thereof, cooperating interlocking means between the bushing and the conducting member including a recess in the central portion of the conducting member and a projecting portion of the bushing received in the recess, the projecting portion of the bushing being formed in the recess of the conducting member during the molding process, an internal annular groove in the bushing opening toward the central portion of the conducting member, an O-ring received in the groove and forming a gas-tight seal between the conducting member and the bushing, a first external annular groove in the outer surface of the bushing for reception of a snap ring, an annular collar on the outer surface of the bushing between the external annular groove and the outer end portion of the cOnducting member and forming a shoulder portion facing the first external annular groove and engageable with a step portion of the wall of the casing about the opening, a second external annular groove in the outer surface of the bushing for receiving an O-ring and positioned closely adjacent to the shoulder portion on the side thereof nearest the first external groove, a projection on the shoulder portion extending axially of the bushing toward the second external groove for reception in a complementary recess in the step portion of the wall of the casing, and an annular collar on the conducting member in abutting relation with the end face of the bushing nearest the outer end portion of the conducting member, said annular collar being sized so as to cause a high electrical field gradient when voltage is impressed on the conducting member thereby to insure harmless external flash over of electrical charges from the surface of the conducting member.

Claim 3

The bushing assembly of claim 1 wherein the interlocking means also comprises a second recess spaced circumferentially from said recess on the central portion of the conducting member and a projecting portion of the bushing received in the second recess.

Claim 4

The bushing assembly of claim 1 wherein the bushing is formed of an alkyd polyester.

Claim 5

A bushing assembly and casing combination, said bushing assembly and casing being in gas-tight engagement with each other, said combination comprising a bushing assembly including a generally cylindrical insulating bushing having an axial opening and an elongated conducting member having a cylindrical central portion which is received in the opening and having inner and outer end portions extending axially away from the bushing from respective opposite ends thereof, the insulating bushing being molded about the cylindrical central portion, interlocking means between the bushing and conducting member, the bushing having an internal annular groove opening toward the central portion of the conducting member, an O-ring received in the groove and forming a gas-tight seal between the conducting member and the bushing, an annular collar about the conducting member in abutting relationship with the end face of the bushing nearest the outer end of the conducting member for preventing leakage of external electrical charges along the conducting member, a casing having walls and a wall of the casing having a circular opening therethrough, an annular boss on the casing wall around the opening extending inwardly of the outer surface of the wall and having an inner end portion radially inset to define an annular step portion, a recess in the step portion of the boss, an annular shoulder on the outer surface of the bushing engaging the step portion, a projection on the shoulder of the bushing received in the recess in the step portion to prevent rotation of the bushing with respect to the casing, an annular groove in the outer surface of the bushing closely adjacent the shoulder portion of the bushing, an O-ring received in the annular groove engaging both the shoulder of the bushing and an inner surface portion of the boss to provide a seal therebetween, a second annular groove in the outer surface of the bushing displaced inwardly of the casing wall from the shoulder of the bushing, said inner end portion of the boss defining an annular edge face, and a snap ring received in the second annular groove and in engagement with the annular edge face of the boss, engagement of the snap ring in the second annular groove compressing the O-ring in the first annular groove thereby to provide a seal between the exterior surface of the bushing and the wall of the casing.

Claim 6

A bushing assembly and casing combination, said bushing assembly and casing being in gas-tight engagement with each other, said combination comprising a bushing assembly including a generally cylindrical insulating bushing having an axial opening and an elongated conducting member having a cylindrical central portion which is received in the opening and having inner and outer end portions extending axially away from the bushing from respective opposite ends thereof, the insulating bushing being molded about the cylindrical central portion, interlocking means between the bushing and conducting member, the bushing having an internal annular groove opening toward the central portion of the conducting member, an O-ring received in the groove and forming a gas-tight seal between the conducting member and the bushing, an annular collar about the conducting member in abutting relationship with the end face of the bushing nearest the outer end of the conducting member for preventing leakage of external electrical charges along the conducting member, a casing having walls and a wall of the casing having a circular opening therethrough, an annular boss on the casing wall around the opening extending inwardly of the outer surface of the wall and having an inner end portion radially inset to define an annular step portion, a recess in the step portion of the boss, an annular shoulder on the outer surface of the bushing engaging the step portion, a projection on the shoulder of the bushing received in the recess in the step portion to prevent rotation of the bushing with respect to the casing, an annular groove in the outer surface of the bushing closely adjacent the shoulder portion of the bushing, an O-ring received in the annular groove engaging both the shoulder of the bushing and an inner surface portion of the boss to provide a seal therebetween, a second annular groove in the outer surface of the bushing displaced inwardly of the casing wall from the shoulder of the bushing, said inner end portion of the boss defining an annular edge face, and a snap ring received in the second annular groove and in engagement with the annular edge face of the boss, engagement of the snap ring in the second annular groove compressing the O-ring in the first annular groove thereby to provide a seal between the exterior surface of the bushing and the wall of the casing.

Claim 7

The bushing assembly and casing combination of claim 4 wherein the inner edge face slopes downwardly toward the outer periphery of the inner end portion of the boss.