Timepiece, in particular a pocket watch, equipped with at least one cover

A timepiece, comprising a case delimited by a middle part and at a centre of which a horological movement is housed, the timepiece further comprising, on at least one of front or rear faces thereof, a cover covering a device for displaying a piece of information or a decorative pattern, the timepiece further comprising a device for opening the cover, said cover being held in the closed position by a locking spring, the opening device comprising a fixed pendant mounted inside the middle part of the timepiece, in addition to a movable pendant capable of sliding coaxially within the fixed pendant towards the centre of the case, the movable pendant being equipped with a guide element capable of moving along an axial guide groove, then in a circumferential guide groove into which the axial guide groove opens out, the axial guide groove and the circumferential guide groove being made in an inside surface of the fixed pendant, the circumferential guide groove being provided with a boundary away from the place at which the axial guide groove opens out, such that, when the movable pendant is pushed towards the centre of the case, said movable pendant can be firstly displaced axially, then pivoted by an angle defined by the place at which the guide element abuts against the boundary which delimits the circumferential guide groove, the opening device further comprising at least one pin which extends axially towards the centre of the case and which is arranged with a clearance between the movable pendant and the locking spring, the movable pendant having, on the side of the pin, a helical groove, said helical groove coming into contact with the pin and causing the axial displacement thereof towards the locking spring when the movable pendant is pushed, then pivoted, such that the pin presses against the locking spring and releases the cover from the retaining force exerted thereon by the locking spring.