Abstract: A depth indicator is associated with a tractor. The depth indicator includes an above depth indicating circuit, an at depth indicating circuit and a below depth indicating circuit, with each circuit including visual indicators which are associated with each other so that once energized, a visual indicator will remain energized until another visual indicator is energized.A tractor mounted ripper tool employs a programmable control device to change the angular attitude of the ripper blade at a preselected depth.The control device positions a diverter valve to alternately apply fluid power between a depth positioning power cylinder and a pitch positioning power cylinder such that the attitude of the ripper blade will automatically be changed between a penetrating mode and a ripping mode at a preselected depth. A depth control circuit having a depth sensor switch and a depth selector switch detects the vertical displacement of the ripper tool and provides a command at a preselected depth.

Abstract: A tractor mounted tool employs a programmable control device to change the angular attitude of the tool to a work surface at a preselected depth and also indicate the relative depth at which the tool is working. The control device positions a diverter valve to apply fluid power alternately between a depth positioning power cylinder and a pitch positioning power cylinder such that the attitude of the tool is automatically changed between a penetrating mode and a working mode at a preselected depth. A depth control circuit having a depth sensor and a depth selector which monitor the depth position of the tool in relation to a preselected depth and provide an output command when the tool is detected at the preselected depth. A pitch control circuit having a pitch sensor and a pitch selector which monitor the angular displacement of the tool and provide an output command at a preselected pitch.

Abstract: A tractor mounted ripper tool employs a programmable control device to change the angular attitude of the ripper blade at a preselected depth.The control device positions a diverter valve to alternately apply fluid power between a depth positioning power cylinder and a pitch positioning power cylinder such that the attitude of the ripper blade will automatically be changed between a penetrating mode and a ripping mode at a preselected depth. A depth control circuit having a depth sensor switch and a depth selector switch detects the vertical displacement of the ripper tool and provides a command at a preselected depth. A pitch control circuit having a pitch sensor switch and a pitch selector switch detects the angular displacement of the ripper tool and provides a command at a preselected pitch.