Abstract: A modular microphone assembly housed in a handsfree telephone apparatus provides an environment that is isolated from a loudspeaker installed within the apparatus and through which environment the directional and frequency response characteristics of a directional microphone capsule contained within a closable cavity of a microphone mounting receptacle in the assembly are altered via a predetermined internal surface configuration of the receptacle to improve the performance of the apparatus.

Abstract: A telephone hook switch uses an elastomeric member as the contact making member. A hook switch has a pivotally mounted actuating member having two levers extending in opposite directions, one on each side of the pivot axis. One lever is moved by the positioning, and removal, of a handset, the actuating member being biased to a particular pivotal direction. The other lever presses on a deformable projection in the elastomeric member. Depression of the projection causes an electrically conducting layer to move into contact with contact areas of a switch position on a printed circuit board.

Abstract: A turbine-driven sander includes a direct drive system in which a one-piece thermoplastic shaft is rotatably journalled in a housing and mounts a two-piece turbine at one end and a counterweight and bushing at the other end. A machine screw is inserted through a longitudinal clearance bore in the shaft and clamps the turbine halves, shaft, counterweight and bushing together. The bushing is in turn pressed into a ball bearing, which is mounted in a platen. When the turbine rotates, the platen is oscillated, balanced by the counterweight.

Abstract: A turbine-driven sander includes a minimum of one-piece sealed housing members so interconnected as to form a nozzle, a turbine chamber, and a valve chamber. A plurality of elongated support members are integrally formed on a housing member. Fasteners are inserted in the elongated support members to clamp the housing members together. A flap valve mounted in the valve chamber opens the turbine chamber to a source of vacuum, thereby driving a turbine rotatably mounted in the turbine chamber. This rotation in turn vibrates a platen through a direct-drive system. The platen is supported upon one of the housing members by two platen support members. A noise attenuation system at the front end of the housing includes a two-passage nozzle which is curved to interrupt the line of sight from a turbine air inlet to the turbine. A side branch resonator communicates with the nozzle via noise-attenuating holes in a cover plate located above the nozzle.

Abstract: A turbine-driven sander includes a nozzle, turbine chamber, and a valve chamber. A flap valve mounted in the valve chamber opens the turbine chamber to a source of vacuum, thereby driving a turbine rotatably mounted in the turbine chamber. This rotation in turn vibrates a platen through a direct-drive system. The platen is supported upon one of the housing members by a pair of platen support members, each member being temporarily connected to a metal plate to form a subassembly. Each platen support member is a molded plastic unit having a cross-member, a pair of snaps for engaging the metal plate, and a pair of flexible posts extending from each end of the cross-member. The support member is attached to a mating recess in the lower surface of a housing member. The flexible posts are attached to a platen.

Abstract: An improved flap sanding, surface finishing device is described having a manually operable member positioned outside a housing of the device for unwinding an abrasive strip stored in the housing in order to replenish worn strip segments. The device includes means for selectively inhibiting and enabling unwinding.