BRAKE FOR LINEAR MOVEMENTS OF RODS

The linear brake defines a longitudinal axis (A) and comprises a tubular housing (12) for axial engagement about a post (P) and a radially deformable tubular friction sleeve (22) for axial engagement along the post, the friction sleeve located radially spacedly within an inner wall of the housing. The linear brake also comprises an annular axially convergent ball channel defined between the housing inner wall and the friction sleeve and a number of balls (38) disposed in an annular row within the ball channel, the balls being axially movable between a non-braking position in which they apply little or no radial pressure against the friction sleeve for allowing the friction sleeve to freely slide along the post; and a braking position in which the balls are wedged between the housing inner wall and the friction sleeve and apply significant radial pressure against the friction sleeve to forcibly radially inwardly deform the friction sleeve for the friction sleeve to apply friction-borne radial pressure against the post for hindering movement of the linear brake along the post. The linear brake further comprises a number of axially extending, peripherally spaced grooves (24) provided on the friction sleeve, each the ball being seated in a corresponding one of the grooves, an actuator (40) continuously biasing the balls towards the braking position and a counter-actuator attached to the housing and which selectively moves the balls into the non-braking position against the action of the actuator. L'invention concerne un frein linéaire définissant un axe longitudinal (A) et comprenant un logement tubulaire (12) pour engagement axial, autour d'un arbre (P), et un manchon de frottement tubulaire (22) radialement déformable pour engagement axial, le long de cet arbre, lequel manchon de frottement est situé, de façon radialement espacée, au sein d'une paroi intérieure dudit logement. Ce frein linéaire comprend également un canal annulaire à billes axialement convergent, défini entre la paroi intérieure du logement et le manchon de frottement, et un certain nombre de billes (38) disposées en rangée annulaire à l'intérieur du canal à billes, ces billes pouvant être déplacées axialement entre une position d'absence de freinage, dans laquelle elles n'exercent qu'une légère voire aucune pression radiale sur le manchon de frottement afin de permettre à ce dernier de glisser librement le long de l'arbre, et une position de freinage, dans laquelle ces billes sont calées en