Manhole cover locking bolt construction
AssigneeMcGard, Inc.
InventorDurham S. McCauley
Life of this patent
Estimating the term…
Abstract
A manhole cover locking bolt construction for locking a manhole cover to an associated frame including a bolt having a threaded shank and an externally threaded head and an endless curvilinear groove in the top of the head for receiving a key of mating configuration for threading the bolt into and out of the manhole cover frame, and a cap for threadably mounting on the externally threaded head to protect the curvilinear groove against entry of foreign matter.
Claims11
A manhole cover locking bolt for locking a manhole cover against removal from its associated frame comprising a shank, first thread means on said shank for reception in a tapped bore in said frame, head means affixed to said shank for bearing on a lip on the manhole cover when said shank is screwed into said tapped bore to thereby prevent said manhole cover from being lifted out of said frame, second thread means on the outer periphery of said head for receiving a mating cap, a top on the opposite side of said head from said shank, and curvilinear groove means in said top of said head for receiving a mating key.
In a manhole cover mounted in a frame having a threaded bolt-receiving bore therein, an upper end and a lower end in said bolt-receiving bore, a first depression in said frame proximate said upper end of said bolt-receiving bore, a second depression on said manhole cover adjacent said first depression, and lip means on said manhole cover at the base of said second depression, the improvement comprising a manhole cover locking bolt comprising a shank, first thread means on said shank for mating engagement with said threaded bolt-receiving bore in said frame, a head affixed to said shank for entry into said adjacent first and second depressions, an undersurface on said head for bearing on said lip means, a top on said head, curvilinear groove means in said top of said head for receiving a mating key, and second thread means on the outer periphery of said head for receiving a cap for protecting said curvilinear groove means against the entry of solid foreign matter.
Dependencies are inferred from the claim text.