US Patent 7526826 Folding ramp

A folding ramp (20) generally includes at least first and second ramp sections (24 and 26), and a first hinge assembly (22) coupling the first and second ramp sections. The first hinge assembly includes adjacent first and second collars (44A and 44B), wherein a first portion of a tongue and groove coupling device (60A) of the first collar is coupled to a second portion of the tongue and groove coupling device (62A) of the first ramp section and a first portion of a tongue and groove coupling device (60B) of the second collar is coupled to a second portion of a tongue and groove coupling device (62B) of the second ramp section. The first hinge assembly further includes a hinge pin (48), wherein the first and second collars are designed and configured to rotate in opposite directions around the hinge pin.