Rotatable drive member formed from injection molded plastics material with preform insert

A rotatable drive pulley formed from plastics material that is molded about portions of inner and outer metal inserts that have been formed prior to the molding of the plastics material, comprising:

• (a) a preform inner metal insert that comprises an elongate tubular sleeve-like piece of metal having an inner surface that defines a hole for receiving a shaft to mount the drive member for rotation about the axis of the shaft, and an outer surface that defines non-circular formation means for drivingly engaging injection molded plastics material;
• (b) a preform outer metal insert that comprises an annular disc-like member that is formed by stamping a blank of sheet metal such that inner and outer edge, portions of the blank which define the inner and outer diameter of the annular disc-like member are bent out of the plane of the remainder of the sheet metal blank, with the preform outer metal insert extending about the outer surface of the preform inner metal insert but with the inner edge portions of the preform outer metal insert spaced from the outer surface of the preform inner metal insert, and with said plane of the remainder of the blank extending substantially orthogonally with respect to the axis of the shaft about which the preform inner metal insert mounts the drive member for rotation;
• (c) a one-piece member that has been formed from plastics material injection molded in situ about the outer surface of the preform inner metal insert, and about the inner and outer edge portions of the preform outer metal insert, with the plastics material cooperating with the preform inner metal insert to form hub means for extending about the shaft, and cooperating with the preform outer metal insert to form ring-like rim means that extends coaxially about the hub means in radial spaced relationship thereto in the vicinity of the outer edge portions;
• and,
• (d) drive formation means defined by the plastics material and extending circumferentially about the rim means for drivingly engaging another drive element.

A timing belt pulley formed from a single, contiguously-extending, one piece member consisting of plastics material that has been injection molded about portions of a preform inner metal insert and a preform outer metal insert to provide a rigid structure of plastic and metal components, comprising:

• (a) a preform inner metal insert that comprises an elongate tubular sleeve-like piece of metal having an inner surface that defines a hole for receiving a shaft to mount the pulley for rotation about the axis of the shaft, and an outer surface that defines non-circular formation means for drivingly engaging injection molded plastics material;
• (b) a preform outer metal insert that comprises an annular disc-like member that is formed by stamping a blank of sheet metal such that inner and outer edge portions of the blank which define the inner and outer portions of the blank which define the inner and outer diameter of the annular disc-like member are bent out of the plane of the remainder of the sheet metal blank, with the outer metal insert extending about the outer surface of the preform inner metal insert but with the inner edge portions spaced from the outer surface of the preform inner metal insert, and with said plane of the remainder of the blank extending substantially orthogonally with respect to the axis of the shaft about which the preform inner metal insert mounts the pulley for rotation;
• (c) a one-piece member that has been formed from plastics material injection molded in situ about the outer surface of the preform inner metal insert, and about the inner and outer edge portions of the preform outer metal insert, with the plastics material forming a ring-like rim in the vicinity of the outer edge portions;
• and,
• (d) the plastics material additionally defining drive formation means extending circumferentially about the rim for drivingly engaging another drive element.