How a leg goes onto the body, and what holds it there

A drawer with a door bolt: the triangular head of the leg root slides into the V rim on the body face and is held down by two roofs, so the only way out is back the way it came. Two spring bolts snap out in front of two solid stop walls and block that way. Pinch the two paddles, the bolts retract, and the leg pulls out.

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    How it holds

    1. The triangular head sits in the V rim: the rim stops it going forwards or sideways, the roofs stop it going up.
    2. The only way out is to slide back towards the base edge, and it has to slide to come free.
    3. Two bolts stand in front of two stop walls and block that way. The springs keep pushing them out, so there is no play.
    4. For the leg to come off, both bolts have to retract at the same time: that is, both paddles pinched.
    5. For transport or a long run, a printed safety clip goes on each paddle (the chevron on top points at the leg root): the paddle can then be pushed in only part of the way, and the bolt cannot pass its wall.

    Numbers used in the animation

    Set-down position
    Bolt out when locked
    If a wedge slips, the flats meet
    One bolt alone: movement on the free side
    Pinching one paddle
    One leg (with 3 servos)

    All from the V83 CAD checks, with the bolt drawn in the middle of its channel. Under load a real bolt lies slightly askew and stands about 0.7 mm further out (see Process). Not yet verified with springs on hardware; drops, wear and fatigue are not covered.

    Shapes are from the V83 CAD (v83_htd45h_snap_bolt); displacements are drawn at their checked values, not exaggerated. Fingers and arrows are only indicative. For the whole robot see the assembly bench.