Abstract: An improved luminometer is provided which uses a top loading plate carrier which receives a microtitration plate and uses a mask having an aperture corresponding to each test cell in the plate carrier. When the mask rotates downwardly to cover the microtitration plate, the plate carrier automatically orients the microtitration plate in the X, Y and Z directions. Reagents are added to the individual test cells through the mask aperture. Each reagent injector is extendable and retractable so that liquids can be added below the mask aperture during purging or washing and then the injector retracted. A pump is provided for each injector which is driven by a stepper motor and a rack and pinion connection to a syringe.

Abstract: According to a first aspect of the invention, a power control switch comprises two solid state switching elements (14, 15) in parallel, the second switching element (15) having a higher resistance but faster turn-off time than the first element. In operation the switch is pulse width modulated and the first element is switched off after the second element to establish a guard period, the duration of which is controlled in dependence upon the duty cycle to provide efficient switching. According to a second aspect of the invention a power control switch comprises a switching element (14 or 15) controlled by a field programmable gate array (5) which is preferably programmed by an erasable programmable read only memory (EPROM), thereby providing a reconfigurable control means.

Abstract: A portable motor-driven device is described for cleaning balls. The device includes a cup having a cleaning medium mounted therein which forms all or a portion of a ball receiving recess and a spindle disposed thereover. The spindle engages a ball retained within the recess, and a motor provided rotates the spindle thereby rotating the ball against the cleaning medium. A solvent may be used if desired.

Abstract: There is disclosed therein a method and a tufted construction formed of a thermoplastic sheet which defines a two-dimensional projection of a three-dimensional tufted construction design which has integrally mutually spaced prefused tufts mounted at preselected areas on one surface thereof. The three-dimensional design includes a radial surface having said tufts thereon and a handle portion so that when the projection is assembled and the edges thereof joined, the three-dimensional design will be complete.