Abstract: A lock comprising a roller stop having a forward end; at least a first roller receiving concavity mounted for movement across the forward end of the roller stop; a roller mounted for movement between forward and rearward positions, the roller, while at its forward position, extending into the at least first roller receiving concavity and overlying the forward end of the roller stop; a plunger having a forward end and a rearward end, the plunger being mounted for motion between forward and rearward positions, the plunger, while at its forward position, holding the roller at its forward position, the plunger, while at its rearward position, allowing the roller to move to its rearward position; and a toggle mounted for alternate flexion and hyperextension, the toggle, upon hyperextension, holding the plunger at its forward position, the toggle, upon flexion, holding the plunger at its rearward position.

Abstract: A seat support having a clevis having an annular base and upper and lower arms rotatably mounted on and extending radially outward from the annular base; at least a first support column extending downwardly from the annular base; seat mounting ball bushings having at least a first laterally extending tongue, the at least first tongue being received by the clevis; and at least a first clevis pin attaching the at least first tongue to the clevis.