Hollow plastic break-away post

Claim 1

A hollow plastic post for street markers and the like comprising in combination: an elongated hollow post shaft in the form of a continuous profile of plastic material; a post base solidly connected to the lower end of the shaft; and means for anchoring the post base to the ground; the profile of the shaft including a closed outer wall in the form of a shell, and several interior stiffening members integrally connected to the shell, thereby increasing the bending resistance of the shaft profile, wherein the post base is likewise of plastic material and hollow, and includes a lower anchoring portion of substantially cylindrical outline and an upper transition portion, by which it is solidly connected to the lower end of the shaft; the anchoring means include a plurality of cam noses near the lower end of the anchoring portion of the post base, the cam noses being angularly spaced apart and radially protruding from the outer periphery of the anchoring portion and including each a metallic nose insert; the anchoring means further including a radial shoulder on the anchoring portion at a distance above the cam noses, the shoulder having a radius greater than that of the cam noses; the anchoring portion with its shoulder and cam noses being thus adapted to be locked into a fixed anchoring socket in the manner of a bayonet lock, if the anchoring socket has a matching bore with an upper end face to support the shoulder and matching interior locking noses in the form of radial protrusions which can be engaged from underneath by the cam noses; the wall of the hollow anchoring portion being adapted to yield radially inwardly to permit the cam noses to successively snap out from under the locking noses of an anchoring socket as described earlier, when a horizontal force is applied to the post shaft which creates a predetermined pivoting moment on the base, thus causing the post to break away from the anchoring socket without damage to either.