A lock assembly used on roof ventilating windows or doors comprising a locking device having: a casing designed to be mounted on a sash which is arranged to tilt pivotally inside a main frame of the window or the door, a strike plate designed to be mounted on the main frame of the window to be located opposite the casing when the sash is in a closed position, having a pair of stationary latching members (22, 24), a pair of latching hooks (26, 28) mounted on the casing and arranged to pivot about two respective rotation axis (A1, A2) sensibly parallel to each other, each latching hook (26, 28) being able to pivot between a locking position in which each latching hook (26, 28) is in a locking engagement with respective stationary latching members (22, 24) to lock the sash in the closed position and an unlocking position in which each latching hook disengages from the respective stationary latching members to allow opening of the window or the door, an actuation slider arranged at least partly in the casing between the two rotation axis (A1, A2) of the latching hooks (26, 28) and mounted to slide in translation along a sliding direction sensibly perpendicular to the rotation axis (A1, A2), the actuation slider being linked to the latching hooks (26, 28) so that the translation motion of the actuation slider entails a pivoting motion of the latching hooks, characterized in that each of the latching hooks (26, 28) is mounted on a pair of corresponding pinions (40, 42) which is mounted rotatable inside the casing and has the same rotation axis (A1, A2) as the latching hook, and the actuation slider comprises at least two laterally opposed rack portions (32, 34) which respectively engage with the pair of corresponding pinions (40, 42). a casing designed to be mounted on a sash which is arranged to tilt pivotally inside a main frame of the window or the door, a strike plate designed to be mounted on the main frame of the window to be located opposite the casing when the sash is in a closed position, having a pair of stationary latching members (22, 24), a pair of latching hooks (26, 28) mounted on the casing and arranged to pivot about two respective rotation axis (A1, A2) sensibly parallel to each other, each latching hook (26, 28) being able to pivot between a locking position in which each latching hook (26, 28) is in a locking engagement with respective stationary latching members (22, 24) to lock the sash in the closed position and an unlocking position in which each latching hook disengages from the respective stationary latching members to allow opening of the window or the door, an actuation slider arranged at least partly in the casing between the two rotation axis (A1, A2) of the latching hooks (26, 28) and mounted to slide in translation along a sliding direction sensibly perpendicular to the rotation axis (A1, A2), the actuation slider being linked to the latching hooks (26, 28) so that the translation motion of the actuation slider entails a pivoting motion of the latching hooks, characterized in that each of the latching hooks (26, 28) is mounted on a pair of corresponding pinions (40, 42) which is mounted rotatable inside the casing and has the same rotation axis (A1, A2) as the latching hook, and the actuation slider comprises at least two laterally opposed rack portions (32, 34) which respectively engage with the pair of corresponding pinions (40, 42).