Abstract: A wheel chock includes a convex load surface configured to be engaged by a vehicle tire. The resultant force exerted by the vehicle tire on the wheel chock can be expressed as a vector normal to the convex surface, at a contact angle ?. As dynamic loading forces push the vehicle into the wheel chock, the tire rides up the convex surface of the chock, thereby increasing the contact angle ?. For contact angles greater than 45°, the vertical component of the resultant force will increase, and the horizontal component will decrease. The net effect is that, under dynamic loading, the chock will tend to anchor itself downwards rather than slide backwards or tip over. Also disclosed is a chock extractor secured to the wheel chock. Rotating the extractor handle in turn rotates an extractor foot, which pivots and lifts the wheel chock off the ground to disengage the chock.

Abstract: An impact resistant sectional door includes a plurality of interlockingly coupled extruded thermoplastic polymer elongated panels. An elongated panel edge includes a channel and an adjacent edge of an adjacent panel includes a protrusion. The protrusion nests in the channel. Each end cap is rotatingly coupled to an adjacent end cap by a door hinge. The roller is adapted to ride in a door track and to pivot about a rolling plane of the roller. An impact load applied to one or more elongated panels causes one or more of the elongated panels to elastically deform at a spring rate in response to the impact and one or more of the protrusions to slide away from one or more of the channels. The impact resistant sectional door remains substantially undamaged. A method for protecting a sectional door from an impacting force is also described.

Abstract: An impact resistant sectional door includes a plurality of interlockingly coupled extruded thermoplastic polymer elongated panels. An elongated panel edge includes a channel and an adjacent edge of an adjacent panel includes a protrusion. The protrusion nests in the channel. Each end cap is rotatingly coupled to an adjacent end cap by a door hinge. The roller is adapted to ride in a door track and to pivot about a rolling plane of the roller. An impact load applied to one or more elongated panels causes one or more of the elongated panels to elastically deform at a spring rate in response to the impact and one or more of the protrusions to slide away from one or more of the channels. The impact resistant sectional door remains substantially undamaged. A method for protecting a sectional door from an impacting force is also described.