A New Reliability Measure for Essential Matrices Suitable in Multiple View Calibration

A safety leg construction for a dockboard which acts to limit normal slow descent of the ramp, as well as rapid descent of the ramp, after a truck pulls away from the loading dock. Legs are hinged to the undersurface of the forward edge of the ramp and are biased to a forward supporting position and can be pivoted to a retracted non-supporting position. The legs are coupled to the lip of the dockboard by a coupling member which is pivoted to the leg and has an abutment positioned to be engaged by a cam attached to the lip as the lip is extended to thereby move the coupling member and the leg to the retracted position. An acceleration responsive latching element serves to lock the coupling member to the leg so under normal operation they move as a unit. Under a rapid gravitational descent of the ramp, caused by an added load on the ramp when the truck pulls away from the dock, the increased acceleration of the ramp will actuate the latching element to release the coupling member from the leg and enable the biasing means to return the leg to the supporting position, independent of the position of the lip and coupling member, to thereby support the ramp against further descent.