Abstract: A lamp socket has a housing forming a cavity centered on an axis and having a generally cylindrical side wall and a floor, an internally threaded sleeve coaxially received in the cavity, a central socket contact on the floor at the axis, and an annular disk separate from the housing, surrounding the central contact. The disk is formed on the axis with a central aperture and is spaced at the aperture substantially further from the floor than the central socket contact. Thus only a lamp base with a central lamp contact on an extension stem can fit in the socket and engage through the aperture and past the disk to make contact with the central socket contact.

Abstract: A lamp socket has a housing forming a cavity centered on an axis and having a generally cylindrical side wall and a floor, an internally threaded sleeve coaxially received in the cavity, a central socket contact on the floor at the axis, and an annular disk separate from the housing, surrounding the central contact. The disk is formed on the axis with a central aperture and is spaced at the aperture substantially further from the floor than the central socket contact. Thus only a lamp base with a central lamp contact on an extension stem can fit in the socket and engage through the aperture and past the disk to make contact with the central socket contact.

Abstract: A lamp has a polygonal-section plug part extending along an axis and having at least one radially outwardly directed face formed with a radially outwardly projecting retaining bump. A socket has a core body formed with a polygonal-section socket hole complementary to the plug part and into which the plug part can be fitted axially in an installed position and that substantially completely prevents angular displacement of the plug part relative to the core body in the installed position. A sleeve surrounds the core body and can angularly shift relative thereto between a freeing end position and a blocking end position. The sleeve is formed with a radially inwardly projecting retaining formation that, in the installed position of the plug part, is angularly offset from the bump in the freeing position and that operatively engages and blocks axial displacement of the bump in the blocking position.

Abstract: A lampholder has an inner part centered on an axis and formed with a radially extending and axially open inner slot having a predetermined small width. It also has an outer part surrounding the inner part and formed relative to the axis with a radially extending and axially open outer slot of a predetermined large width. A lamp pin of a width greater than the small width but smaller than the large width cannot slide through the outer slot into the inner slot. The inner part is separable from the outer part.

Abstract: A lampholder has an inner part centered on an axis and formed with a radially extending and axially open inner slot having a predetermined small width. It also has an outer part surrounding the inner part and formed relative to the axis with a radially extending and axially open outer slot of a predetermined large width. A lamp pin of a width greater than the small width but smaller than the large width cannot slide through the outer slot into the inner slot. The inner part is separable from the outer part.

Abstract: A lampholder having an inner part and an outer part is formed relative to an axis with a radially extending and axially open slot in turn having an inner portion in the inner part and an outer portion in the outer part. The portions are alignable with each other and both have a predetermined large width. An adapter has a body shaped to fit with one of the lampholder parts and having a formation engaged in the respective slot portion to define therein an adapter slot aligned with the respective slot portion and of a small width substantially less than the predetermined large width so that a lamp pin of a width greater than the small width but smaller than the large width cannot slide through the one slot portion. The adapter body is fixed to the one part of the lampholder.

Abstract: A lamp has a polygonal-section plug part extending along an axis and having at least one radially outwardly directed face formed with a radially outwardly projecting retaining bump. A socket has a core body formed with a polygonal-section socket hole complementary to the plug part and into which the plug part can be fitted axially in an installed position and that substantially completely prevents angular displacement of the plug part relative to the core body in the installed position. A sleeve surrounds the core body and can angularly shift relative thereto between a freeing end position and a blocking end position. The sleeve is formed with a radially inwardly projecting retaining formation that, in the installed position of the plug part, is angularly offset from the bump in the freeing position and that operatively engages and blocks axial displacement of the bump in the blocking position.

Abstract: A lampholder having an inner part and an outer part is formed relative to an axis with a radially extending and axially open slot in turn having an inner portion in the inner part and an outer portion in the outer part. The portions are alignable with each other and both have a predetermined large width. An adapter has a body shaped to fit with one of the lampholder parts and having a formation engaged in the respective slot portion to define therein an adapter slot aligned with the respective slot portion and of a small width substantially less than the predetermined large width so that a lamp pin of a width greater than the small width but smaller than the large width cannot slide through the one slot portion. The adapter body is fixed to the one part of the lampholder.

Abstract: A lampholder has an outer sleeve centered on an axis and having a radially inwardly projecting lug having an axially inwardly directed end face and an inner core adapted to fit with a lamp, fittable inside the sleeve, and formed with an axially inwardly directed face axially alignable and engageable with the outer-sleeve end face on rotation of the core in the sleeve in a predetermined sense in a fully inserted position of the inner core in the sleeve. Interengageable retaining formations on the core and on the sleeve inhibit rotation of the core in the sleeve opposite to the predetermined sense when the faces are axially aligned with and engage each other.

Abstract: A lampholder has an outer sleeve centered on an axis and having a radially inwardly projecting lug having an axially inwardly directed end face and an inner core adapted to fit with a lamp, fittable inside the sleeve, and formed with an axially inwardly directed face axially alignable and engageable with the outer-sleeve end face on rotation of the core in the sleeve in a predetermined sense in a fully inserted position of the inner core in the sleeve. Interengageable retaining formations on the core and on the sleeve inhibit rotation of the core in the sleeve opposite to the predetermined sense when the faces are axially aligned with and engage each other.

Abstract: A terminal block with grounding capabilities has a stamped plug of U configuration whose bight is adapted to be forced into an opening in a terminal carrier for grounding thereto and whose shanks engage in a conductive element within the body. The shanks extend continuously from the bight to connecting portions which engage in recesses in the conductive element in the body and one of the shanks has a nose reaching over and in form-locking relationship with this conductive element.