Abstract: When the mode change knob of a multi-mode hammer drill is moved to the hammer only position, an electronic sensor sends a signal to a control logic circuit. When the user then depresses the trigger mechanically closing the ON/OFF switch, the control logic circuit applies a voltage either to a holding relay or to the gate of a triac which enables the relay or triac to conduct, thus providing a parallel circuit by-passing the ON/OFF switch. Consequently, when the user releases the trigger and opens the ON/OFF switch, the parallel relay or triac maintains current flow to the motor. It can be seen that in hammer only mode the user can activate the hammer drill by simply tapping the trigger to depress it and does not need to hold down trigger during use of the hammer in operation.

Abstract: When the mode change knob of a multi-mode hammer drill is moved to the hammer only position, an electronic sensor sends a signal to a control logic circuit. When the user then depresses the trigger mechanically closing the ON/OFF switch, the control logic circuit applies a voltage either to a holding relay or to the gate of a triac which enables the relay or triac to conduct, thus providing a parallel circuit by-passing the ON/OFF switch. Consequently, when the user releases the trigger and opens the ON/OFF switch, the parallel relay or triac maintains current flow to the motor. It can be seen that in hammer only mode the user can activate the hammer drill by simply tapping the trigger to depress it and does not need to hold down trigger during use of the hammer in operation.

Abstract: When the mode change knob of a multi-mode hammer drill is moved to the hammer only position, an electronic sensor sends a signal to a control logic circuit. When the user then depresses the trigger mechanically closing the ON/OFF switch, the control logic circuit applies a voltage either to a holding relay or to the gate of a triac which enables the relay or triac to conduct, thus providing a parallel circuit by-passing the ON/OFF switch. Consequently, when the user releases the trigger and opens the ON/OFF switch, the parallel relay or triac maintains current flow to the motor. It can be seen that in hammer only mode the user can activate the hammer drill by simply tapping the trigger to depress it and does not need to hold down trigger during use of the hammer in operation.

Abstract: A hammer drill comprising: a motor; a drive transmission capable of operating in at in at least a rotary mode and a reciprocating mode; a mode change mechanism; a switch which, when closed, provides power to the motor; and a mechanical lock-on mechanism which, when locked mechanically holds the switch closed to maintain the power to the motor. Additionally, the hammer drill includes a first sensor, which indicates the mode of operation of drive transmission; and a second sensor which indicates whether the lock-on mechanism is locked; and a controller which is capable of interfering with the operation of the motor, when the controller detects that the drive transmission is in the rotary mode of operation and the lock-on mechanism has been locked.

Abstract: A device is described for modifying the charging behavior of a charge storage device, such as a capacitor, so that the device charges substantially in accordance with a square law function responsively to a linear charging input current. The device has particular utility in a signal-conditioning system of the type including an averaging detector, a gain stage and a charge storage device coupled between the output of said detector and the input of said gain stage so that the input to said gain stage behaves in a similar manner to the output of an RMS detector.

Abstract: An improved expanding system is described for enhancing transmitted or recorded audio signals previously processed by anyone of several nonlinear amplifying techniques. The system is designed to divide the audio signal received into substantially discrete frequency bands and each band is separately expanded, independently of the other bands, so as to minimize "breathing" and "pumping".

Abstract: An adaptive signal weighting system for use in electrical signal transmission along a signal path comprises a variable filter disposed in the signal path having electrical transmission characteristics capable of varying in response to a first control signal the relationship between the spectral region of dominant energy in a transmitted signal relative to the other spectral regions of the transmitted signal. Frequency discrimination means senses the spectral region of dominant signal energy in the transmitted signal and provides the first control signal as a function of frequency of the dominant signal energy. Gain control means disposed in the signal path and coupled in series with the filter means provides a gain variable on the transmitted signal responsively to a second control signal. This second control signal is logarithmically related to the amplitude of the transmitted signal over at least a portion of the frequency range of the signal.

Abstract: An adaptive signal weighting filter for use in a compander performs a frequency response weighting function so that during the encoding process the spectral region of dominant signal energy of the program signal is preemphasized with respect to other spectral regions and during the decoding process the corresponding spectral regions of the encoded signal are deemphasized with respect to one another in a complementary manner.

Abstract: A current mode operational rectifier has an output terminal connectable as a DC current source of a predetermined polarity, and comprises a high gain amplifier having an inverting input terminal for receiving an input signal current from an AC current source and two alternative transmission paths for providing full wave rectification. The first transmission path includes a first transistor having its base connected to the output terminal of the amplifier and its emitter and collector connected between the output terminal of the rectifier and the input terminal of the amplifier. The first transmission path conducts DC current to the output from the input terminal of the amplifier at an instantaneous level substantially equal to the instantaneous level of the input signal when the input signal is of a first polarity. The second transmission path includes matched second and third transistors.