A clean 3D industrial product diagram of a mechanical unpowered obstacle-crossing attachment for wheelchair front casters, studio white background. Clear visual structure highlighting: 1) One-touch 3-point universal clamp on the frame pipe, 2) 45-degree angled pop-up roller module for gap traversal, 3) Mechanical quick-folding hinge mechanism. No electronics or motors, purely mechanical spring and lever design. High-detail CAD rendering, engineering illustration style with clean callout lines. Voir plus