Abstract: A projector comprises optical elements arranged each to constitute a passage port comprising, on the one hand, a first lens (d.sub.1) ensuring focussing of the light source (3) in the plane to be illuminated, whilst optimizing the correction of optical aberrations and, on the other hand, a second lens (d.sub.2) ensuring a multiplication of the image of the source to permit rendering uniform the illumination in the illuminated plane.

Abstract: In a portable motorized screwdriver, in order to provide for manual use of the screwdriver, to finish screwing in a screw, for example, or to start unscrewing a screw, a mechanism is provided for locking the spindle. This mechanism is coupled to the switch used to start and stop rotation of the spindle. This coupling is arranged so that operation of the switch to start rotation of the spindle is accompanied by unlocking of the spindle and so that returning the switch to the position to stop rotation of the spindle locks the spindle. The locking mechanism is arranged so that when the spindle is locked the screwdriver may be used as a ratchet type manual screwdriver.

Abstract: An accessory box comprises a front and two sides. Each side is provided with a resilient lug which comprises a main portion which extends rearwardly to a vertical abutment and a clip which extends rearwardly from the main portion. When the accessory box is slid into a recess the vertical abutment engages the side wall of the recess and the clip maintains the accessory box in the retracted position. The accessory box can be withdrawn when the resilient lugs are pressed towards one another.

Abstract: A battery charger for charging an electric battery pack has a supply rectifier connectable to the battery pack via a thyristor. A thermistor is mounted on a mechanical structure and brought into thermal contact with a cell of the battery pack to measure the temperature thereof. Comparators control the firing of the thyristor in dependence on the state of the thermal conductive relationship between the thermistor and the cell and also upon dependence of a correct electrical connection between the thermistor and the battery pack.

Abstract: A functional unit for a motorized electrical appliance consists of a supporting block, an electric motor, power take-off means and means for supplying electric current to the motor. The various elements are assembled on the supporting block and therewith comprise a readily assembled, low cost sub-assembly adapted for use in a variety of appliances.A method of assembling the functional unit and the application of the unit to a hand-held cordless vacuum cleaner are also disclosed.

Abstract: An electric battery pack is manufactured by a process whereby an outer insulating casing has contact strips partly inserted through apertures in opposed sides thereof adjacent a closed bottom thereof. A series arrangement of connected batteries is inserted into the casing until the positive and negative poles of the series arrangement engage against the contact strips. A cover having integral inward projections is pressed towards and against the casing to close an open end thereof, the inward projections being stressed and deforming against end batteries to secure all the batteries immovably in position, and the cover being welded to the casing. The inner ends of the contact strips are then welded or soldered to the poles of the series arrangement from outside the casing through access orifices in the closed bottom of the casing.