Cover assembly for vertical exhaust pipes

A gravity actuated protective cover device adapted to be secured upon an upstanding exhaust stack of an internal combustion engine to prevent entry of extraneous matter therein during the inoperative condition of the engine and comprising:

• A. a support member adapted to be secured to the exhaust stack and having a pivot structure mounted thereon, the support member having a clamping formation to straddle and be clamped to the exhaust stack which includes adjustable fastening means, said support member being formed of a pair of metal straps of generally mirror construction connected face to face, the pivot structure and fastening means being generally aligned horizontally when the support member is installed on a stack,
• B. a balance arm mounted on said pivot structure for rocking movement about said pivot structure in a vertical plane, the balance arm having a cover member connected to the front end thereof and a counter-weight vane, the vane and cover member being on respective opposite sides of the pivot structure, the balance arm being adapted for said rocking movement between two positions, one of which is with the cover member disposed over the end of the exhaust stack but without touching the same, the other position being with the cover member substantially rotated away from the stack,
• C. the balance arm being heavier on the cover member side of the pivot than on the vane side of the pivot so that the normal condition of the balance arm is with the cover member in the first of said positions when the engine is not operating,
• D. said straps having ear portions thereof spaced apart to provide a bifurcated portion in which the pivot structure is mounted with said balance arm straddled by said ear portions, and wherein said pivot structure comprises
• (1) a pair of aligned annular flanges with axial passageways therethrough laterally formed on said balance arm, and
• (2) a pair of generally cylindrical plastic sleeve bearings pivotally mounted in axial alignment on a pivot shaft member passing through said ear portions so that each of said bearings is fitted within a respective one of said passageways to seat said respective annular flange thereon, wherein at least one of said sleeve bearings comprises a generally cylindrical body having an annular collar flange formed on one end of said body and positioned so that said collar flange engages a respective one of said ear portions in order to limit axial movement of said sleeve bearing on said pivot shaft, and further wherein said collar and body form an annular shoulder which seats an annular foot formed on said respective flange for further stabilization of said balance arm on said pivot structure.