M.a. Industries, Inc.

Charles W McInvale

Bobbie Don Peacock

Two sided manhole step

Manhole lift insert with frangible positioner

Two-sided manhole step

A frangible insert that is inserted in a pre-positioned bushing in the wall of a manhole form from the convex, easily reached side of the inner form wall. A key in the insert is received in a keyway in the bushing in the form wall so that the insert is properly oriented in the form. Concrete is then poured into the form, enveloping and affixing the insert within the man hole wall. A weakened, frangible region is provided on the insert in a position immediately adjacent to the form wall so that after the concrete is cured, the manhole and form can simply be separated, causing the portion of the insert embedded in the concrete to separate from the insert portion in the form bushing.

Insert forming hole to receive manhole step

A manhole lift insert positioning apparatus consisting of: (1) a threaded nut imbedded in a thermoplastic elastomer molding that fits snugly within a lift insert, and (2) a threaded wing bolt to engage the nut and expand the molding within the insert, thereby locking it in position and drawing the molding against the inside face of the concrete form, thus sealing the insert opening to avoid obstruction of that opening with concrete.

Growing community of inventors

Peachtree City, GA, United States of America

Charles W McInvale