Abstract: Method for charging Ni-Cd batteries with a repetitive and alternating sequence of direct current charging and discharging periods. Steep current pulses are superimposed on the respective direct currents which have a sense equal to that of the direct current and intensity exceeding respective predetermined levels. Owing to the effects of such alternating and repetitive current pulses the surface distribution of the electrodes will change after some time and the electrode surface gradually become homogeneous.The periodically repetitive steep current pulses can be used during the whole charging process and they have beneficial effects for the charging of new batteries as well.The current changes at the beginning of the respective periods should be at least seven times as high as one tenth of the ampere-hour capacity of the battery.

Abstract: A tape-conveying system for forward and backward playing magnetic tape recorder and/or playback unit is disclosed a motor (19) driving the magnetic tape (8) at the required speed, a sound shaft (2) interconnected with the motor (19) and fixed through a bearing to a frame (1), a device transmitting movement of the sound shaft (2) to the magnetic tape (8) form a drive mechanism, two winding shafts (4, 5), tape-spindles (6, 7) placed on said winding shafts (4, 5) and winding and unwinding mechanisms connected with the winding shafts, these mechanisms being asynchronous winding clutches (22, 23) and asynchronous unwinding clutches (20, 21) are included in the system. The clothes are interconnected with each winding shaft (4, 5), with the other side of the winding clutches (22, 23) is connected with the driving motor (19). The other side of the unwinding clutches (20, 21) connected with the frame (1), and only one of said connections functions simultaneously on the same winding shaft (4 or 5).