Patent ID: 8506198

Claim:
A shaft coupling assembly comprising: a structural member having an interior surface bounding an opening that has an inlet, the interior surface comprising: a coupling surface encircling a portion of the opening; one or more receiving surfaces disposed between the coupling surface and the inlet of the opening, the one or more receiving surfaces each sloping away from the opening; and one or more alignment ribs, each radially, inwardly projecting from one of the one or more receiving surfaces into the opening; and an elongated shaft having a central longitudinal axis that extends between a proximal end and an opposing distal end, the shaft comprising a driver configured to be received within the opening of the structural member, the driver having an exterior surface along the length thereof, the exterior surface comprising: an engaging surface encircling the longitudinal axis of the shaft; and first and second guide ribs disposed distal of the engaging surface, the first and second guide ribs each extending distally to a distal-most point, the first and second guide ribs bounding a recessed notch therebetween, the first and second guide ribs being configured such that when the driver is being inserted distally into the opening with the first and second guide ribs being aligned with the one or more alignment ribs, the first guide rib contacts a first one of the one or more alignment ribs so that the first guide rib must be offset from the first alignment rib before the driver can be fully received within the opening, wherein each guide rib has opposing side edges that taper inward distally to intersect at the distal-most point in a substantially V-shaped configuration and wherein one of the side edges of the first guide rib intersects one of the side edges of the second guide rib so that the notch is V-shaped.