Releasable zero backlash passive locking mechanism for a vehicle mounted rotary camera mast

A system for mounting to a vehicle, the system comprising:

• a mast structure having a mast and a support frame secured to the mast, the support frame arranged for affixation to a vehicle;
• and
• a locking mechanism, comprising:
• a mast stop member configured for affixation to the mast structure, the mast stop member including at least one receptacle arranged along a first axis, the mast stop member having a first surface that prevents the mast from rotating in a first direction;
• a pawl member having a first end, a second end remote from the first end, and a receptacle disposed between the first end and the second end, the first end being configured to releasable engage a surface of the mast, the receptacle being aligned with the at least one receptacle of the mast stop member along the first axis, and the second end being configured to selectively disengage the first end of the pawl member from the surface of the mast so that the mast is rotatable about a second axis different from the first axis, wherein rotation about the second axis is only permitted in a second direction opposite the first direction;
• a shaft member received by the at least one receptacle of the mast stop member and the receptacle of the pawl member along the first axis;
• and
• a torsion spring received along the shaft member and coupling to the pawl member, the torsion spring securing the first end of the pawl member against the surface of the mast in a deployed state with zero backlash.