MOUNTING AND SWITCHING OF SURVEY APPARATUS

A survey apparatus which can be used in the underground mining industry comprises a mounting means (11) adapted to be mounted in a fixed surface (such as a tunnel wall) and an alignement means (130, 101) to releasably engage with the mounting means (11), wherein the alignement means (130, 101) is capable of operating only when the alignement means (130, 101) is engaged with the mounting means (11). The mounting means (11) is preferably a sleeve member (11) insertable in a wall. The alignement means (130, 101) preferably has a laser module (102) and a suitable compartment for accomodating a battery (151). The mounting means (11), which is a set aligned in the fixed surface, together with the factory-set alignement means (130, 101) is used for the purpose of setting out and alignements. When the cylindrical shaft (133) is inserted into the sleeve member (11), a rod (170), permanently in contact with spring (154) presses against the screw (158) and makes an electrical connection. As the laser module (102) cannot be switched on when out of the sleeve member (11), battery life is improved and improper use is minimized.