Linear motion unit

A linear motion unit, comprising:

• an elongate rod having a longitudinal axis;
• a rigid counter-element extending lengthwise of said rod;
• a runner mounted on said rod for movement lengthwise thereof in a direction of travel (L);
• at least one support unit including a base body for supporting said rod relative to said counter-element and being located either in front of or behind said runner in the direction of travel (L);
• means for supporting said base body for lengthwise movement relative to said rod and to said counter-element and for constraining said base body against rotational movement relative to said rod and to said counter-element;
• a catch member carried by said runner for releasably engaging in latching relationship with said at least one support unit;
• a control element mounted on said base body for movement between at least one latch position and at least one release position, said control element having at least one control recess extending in a first direction (R,V) substantially orthogonal to said direction of travel L;
• and
• a lengthwise-extending control track mounted on said counter-element, said control track including in at least one predetermined lengthwise position a control projection for engagement with said at least one control recess of said control element, said control projection being laterally displaced over at least a portion of its length in a direction transverse to said first orthogonal direction (R,V) such that, upon lengthwise movement of said at least one support unit along said control projection in the direction of travel (L), the control projection moves said control element in a second direction (U,H) substantially orthogonal to both the direction of travel (L) and said first substantially orthogonal direction (R,V).