Hood-lifting actuator with disarmable return braking arrangement

A triggered stroke actuator of the type comprising a cylinder housing a movable assembly comprising a piston and a rod projecting from one end of said cylinder, a propelling unit which is located on one side of said piston and which can provide a propelling force to said piston in response to a trigger command, and a return braking arrangement, wherein:

• the movable assembly further comprises a slidable part that is movable in said cylinder;
• the return braking arrangement comprises at least one ball housed in an annular cavity defined by the inside surface of said cylinder and by said slidable part, said cavity having two adjacent segments extending one another, a first segment having a radial extent that is greater than the diameter of said ball and a second segment having a radial extent that decreases going away from the end of said first segment;
• the return braking arrangement further includes a return spring connecting said slidable part to said piston, so that compression and relaxation of the return spring results in a relative movement of the piston and the slidable part;
• and
• the return braking arrangement further includes a link connecting the at least one ball to the piston, the ball being constrained to move with the link and being positioned by the link in said first segment of the annular cavity when the return spring is relaxed, and in the second segment when the return spring is compressed;
• wherein when the braking arrangement is released when the propelling force applied on the piston drops below a threshold value.