Insulating column for lamp base accepting screwed fitting - uses tubular insulating column with end flange and sliding collar which locks onto column by compression to hold it in place in base

摘要

The insulating piece for an electric lamp holder is manufactured from an electrically insulating material and comprises a tubular column (21) passing through a lamp base, providing a passage for an electric cable and having a flange (22) extending radially from the end of the tube. A movable ring (23) slides along the tubular column towards the end flange (22) and locks onto the column in the vicinity of the end flange (22). The tubular column has a longitudinal slot (26) and longitudinal ridges (27) in the vicinity of the end flange, permitting radial contraction of the tubular column as the ring (23) is slid towards the end flange. The tubular column is inserted in a hole in the external wall of the lamp base and is locked by the sliding ring (23) while the ridges (27) prevent rotation.