Abstract: The present invention provides a control unit for use with a variable speed system for dispersing, milling or otherwise processing solid particles in liquid. The apparatus used in the system includes a fixed center-drive pulley combination. The control unit automatically resets the pulley combination to a slow start-up position to prevent damage to the system drive train during initiation of a processing operation. In addition, the control unit allows a system operator to precisely and safely adjust the setting of the pulley combination to control the speed of the processing operation. In one arrangement the speed is controlled by manually operated valves that control fluid pressure on opposite sides of a piston that controls the pulley combination. In another arrangement, valves automatically control fluid pressure on the piston to maintain a position in response to a signal from a pressure regulator which is manually or otherwise adjusted to provide a selected speed.

Abstract: Cube-shaped, ventilated, individual light modules housing a lamp or bulb having different predetermined characteristics are interchangeably mounted on an expandable clip surrounding an electrical socket, by sliding the module down on the clip and simultaneously establishing electrical contact between the bulb in the module and a power source and switch. The front of the module is faced with safety glass to protect the bulb and subject, and a space is provided between the module and protective safety glass which can be fitted with one or more, swing-away, wide angle adapter, diffuser, or dichroic lenses.

Abstract: A battery pack connection consists of a flat male plate having a plurality of spaced headed projections and female electrical terminals carried within a projecting housing while a flat female plate has a plurality of keyholes designed to facilitate receiving the projections and male electrical terminals positioned within a recess together with a flexible strip that engages a projection to enable locking and unlocking of the plates in both their electrical and mechanical connected relationship. The flexible strip is moved away from its locking position by a cam on a pivoted actuator which can be moved by a finger.

Abstract: An electrical connector and receptacle for use with battery packs and battery charging equipment are disclosed. The electrical connector includes a two terminal coaxial plug and a third contact coaxial with the two terminal plug. The third contact may carry a signal responsive to a selected battery condition, such as temperature, while the two terminals of the coaxial plug carry battery supply voltage. In normal use, the electrical connector supplies power from a battery pack to portable battery powered equipment via an input jack of the portable equipment. The third contact is not used. When charging the battery pack, the electrical connector is plugged into an electrical receptacle of the battery charging equipment and the third contact delivers a signal to the battery charging equipment which indicates battery condition. The battery charging equipment receptacle which mates with the connector is also disclosed.