The roll over frame has vertical tubular sections (6) joined at the tops to form the frame support and with the lower ends guided in a housing (4) via shaped guides. The housing and the uprights are made from lightweight alloy extrusions for lightweight construction with optimum strength. The frame is extended by integral spring force and is locked in the extended position by retaining ratchets. The guides for the uprights are linked by a plate which supports the ratchet grips. The uprights can have an oval cross section for optimum strength. THe frame is released into the extension position by a collision sensor and/or by a roll over sensor.
