Abstract: Timepiece device for simultaneously resetting to zero two time counters, particularly for a chronograph mechanism, each of the two time counters pivoting about an arbour secured to a cam (6b, 8b), the simultaneous zero reset device (1) including a lever (4) with two hammers (6, 8), which are applied against the respective cams (6b, 8b) when the two time counters are reset to zero, at least one pin (10, 12) used to guide the lever (4) with two hammers (6, 8) being secured to said lever (4) and moving in a shaped aperture (24, 26) made in a bridge (28), characterized in that a ring (16a, 16b, 16c) is mounted to rotate freely about the pin (10, 12) and is inserted between said pin (10, 12) and the shaped aperture (24, 26) in which said pin moves.

Abstract: The present invention concerns a watchcase including a middle part (2) defining a housing (4) closed by a crystal and a back cover (6), the back cover (6) having a screw thread portion (14) in a first direction, characterised in that the middle part (2) includes a screw thread portion (16) in a second direction opposite to screw thread direction of the back cover (6), and in that said watchcase further includes an intermediate element (8) having a first screw thread portion (18) cooperating with the screw thread portion (14) of the back cover (6) and a second screw thread portion (20) cooperating with the screw thread portion (16) of the middle part (2).