Abstract: In a battery housing and charging system for a range of cordless tools, a universal charger accepts battery packs of several configurations and size (number of cells). The common feature of the battery packs is (at least) one cell housed on end and substantially coaxial with a specific terminal block assembly. Terminal pins are shielded from external contact and engage the charger terminals in a recessed well in the floor of the charger receptacle. Charger terminals are at one end of the receptacle which is elongated so that it can accommodate a battery pack "nose" portion with either one or two cells housed on end and side-by-side. Upright side walls of the receptacle provide stabilizing support for the battery pack. In the battery pack portion outside the receptacle, cells may be arranged in any configuration to suit tool or other requirements. Charger output terminals are normally biased away from their respective terminal apertures to minimize risk of accidental contact with live terminals.

Abstract: A safety booster cable assembly for connecting a d.c. source to a receiving battery including a normally open relay interrupting the electrical connection between one of the two pairs of electrodes. Circuitry is provided for closing the contact of the relay when the electrodes being connected are of similar polarities. Time delay circuitry is included so that the relay contact is closed after a certain predetermined amount of time has passed so that sparks are prevented from the movement or scratching of the cable clips on the electrodes. Light emitting diodes are connected between the electrodes of the D.C. source and receiving battery so that they illuminate when the correct polarity is observed in the connection of the cable clips.