Apparatus adapted to be mounted in a mounting wall

Claim 3

An apparatus as claimed in claim 1, characterized in that: said mounting spring is a sheet metal blade spring, comprising a central first longitudinal strip, second and third longitudinal strips and a first transverse strip, said means for guiding is arranged to guide said first longitudinal strip for movement solely in a direction parallel to said insertion direction, said first longitudinal strip extending substantially in a plane parallel to the plane of said apparatus wall, and having a free end oriented in a direction opposite to the direction of insertion, said second and third longitudinal strips lie in a plane inclined to the plane containing said first strip, said second and third strips being arranged symmetrically with respect to the first longitudinal strip and being interconnected to said first longitudinal strip at one end, and interconnected to said first transverse strip at an end adjacent said flange, and said shoulder is formed by a portion of said first transverse strip extending at a right angle to said insertion direction.

Claim 4

An apparatus as claimed in claim 2, characterized in that: said means for guiding comprises a guide rib on said apparatus wall, and a slot in said first longitudinal strip extending in a direction parallel to the insertion direction, within which slot the guide rib fits slidably, said apparatus wall has a window spaced from said flange, and the mounting spring comprises a second transverse strip interconnecting the second and third longitudinal strips, and having a projection which is guided in said window.

Claim 5

An apparatus as claimed in claim 3, characterized in that said mounting spring comprises an actuation tongue extending from and at right angles to said spring shoulder; and said apparatus has a further opening through said flange, said tongue extending through said opening, arranged such that, when the apparatus is mounted in a mounting wall opening, the tongue extends through the mounting wall opening so as to be accessible for manually deflecting the mounting spring as a step during removal of the apparatus from an opening in a wall.

Claim 6

An apparatus as claimed in claim 4 characterized in that said further opening communicates with a slot in the flange, said bolt extending through said slot when the apparatus is mounted in a mounting wall, such that the bolt shoulder engages a surface of the flange adjoining said slot; and upon deflection upon said mounting spring during insertion or removal, said tongue and bolt shoulder are each so disposed as to be able to pass through said further opening.

Claim 7

An apparatus as claimed in claim 2 characterized in that said mounting spring comprises an actuation tongue extending from and at right angles to said spring shoulder, and said apparatus has a further opening through said flange, said tongue extending through said opening, arranged such that, when the apparatus is mounted in a mounting wall opening, the tongue extends through the mounting wall opening so as to be accessible for manually deflecting the mounting spring as a step during removal of the apparatus from an opening in a wall.

Claim 8

An apparatus as claimed in claim 1, characterized in that said mounting spring comprises an actuation tongue extending from and at right angles to said spring shoulder, and said apparatus has a further opening through said flange, said tongue extending through said opening, arranged such that, when the apparatus is mounted in a mounting wall opening, the tongue extends through the mounting wall opening so as to be accessible for manually deflecting the mounting spring as a step during removal of the apparatus from an opening in a wall.