Dynamic loudspeaker with plastic basket encapsulating front pole plate

Abstract

A loudspeaker driver has a molded plastic basket made of thermoplastic polyester with 20-30% glass fill and a stamped octagonal front pole plate of low reluctance magnetic material molded into the base of the basket with a keyed central bore. The break edge of the stamped pole plate is used as an undercut for encapsulation. The basket is formed with three tabs spaced equiangularly about the periphery for attachment to the baffle. Accurate upstanding rims extend between the tabs for making engagement with rim segments in a baffle to effect an essentially fluid-tight attachment of the driver to the baffle using snap-in techniques. The tabs are also formed with openings for accommodating screws or other fastening elements to fasten the driver in place with more conventional techniques. Radial ribs extend downward then radially inward from each tab. An exceptionally flat annular surface is just inside the tabs for accommodating the edge of the diaphragm or cone, the roll of which may be either concave or convex. An intermediate portion of the basket extends downward and inward toward the axis of the basket to a second exceptionally flat annular surface for accommodating the voice coil spider which may be fastened thereto by applying heat through the peripheral edge of the spider to the flat surface, causing the plastic material to liquify, flow through the porous material of the spider and solidify when the heat is removed to securely attach the spider to the flat surface.