A lever assembly includes a housing having a pivot slot formed in one end thereof. A lever has a pivot pin slidably and pivotally received in the slot and is pivotal from a centered position to displaced positions. An end of the lever carries a roller. The pivot slot is elongated in a direction which is tilted at an angle with respect to a longitudinal axis of the lever when the lever is in its centered position. A lever spring is biassed to urge the lever to its centered position. The housing also forms a stop which is engagable with the lever to prevent pivoting of the lever into a first displaced position unless the pivot pin slides within the slot and towards the stop. The housing also forms a detent device which engages the roller and releasably holds the lever in a displaced position. Portions of the housing integrally form the stop and the detent device. The detent device is formed in part by a movable member which projects from a central portion of the housing. The movable member forms a first operating surface which faces generally towards the slot, a second operating surface which is tilted with respect to the first operating surface and which faces generally away from the lever when the lever is in its centered position. The operating surfaces are engagable with the roller. A detent spring is biassed to urge the movable member towards the slot.