| abstract |
The invention relates to an instrument head (1) comprising a first element and at least one second element mounted in such a way as to be able to move on the first element between an inactive position and an active position, the head thus being provided with means for relative movement of the second element with respect to the first element, the means comprising at least one preformed rod having a first shape when the rod is outside the head in the idle state, the rod being arranged in the head so as to extend both into the first element and into the second element such that, when the second element is in the inactive position, the rod is constrained in a second shape different from the first shape, the rod gradually returning to its first shape as the second element moves towards its active position. The invention also relates to an instrument and an installation provided with such a head. |