Arrangement and procedure for automatically mounting a unit of equipment on a support, for example a lighting and/or indicating lamp unit on a motor vehicle

An arrangement comprising a support and a unit of equipment removably mounted on the support, the support defining a support wall and the arrangement further including fastening means for removably securing the said unit to the support wall, the said fastening means comprising at least one combination of elements wherein each said combination includes a mounting hole formed through the support wall, a mounting pin carried by the said unit for extending removably through the said mounting hole, and retaining means adapted to engage on the mounting pin and to bear against the support wall so as to secure the mounting pin and therefore the said unit to the support wall, and wherein, in the or each said fastening means:

• (a) the mounting hole comprises a first part having transverse dimensions such as to enable the said retaining means to pass freely through it, and a second part laterally extending the said first part, the dimensions of the second part being smaller than those of the said retaining means whereby to retain the latter in the said second part of the hole;
• (b) the retaining means comprise a retaining ring having a peripheral groove defining a pair of generally transverse flanks and a middle zone separating the said flanks, the transverse dimension of the said flanks being inferior to those of the said second hole part and the longitudinal extent of the said groove being at least equal to that of the corresponding thickness of the support wall, and wherein the said retaining means further comprises a locking means carried by the retaining ring and releasably engaging the said mounting pin, whereby the said generally transverse flanks are adapted to engage on either side of the support wall so as to retain the retaining ring in both longitudinal directions.