Abstract: A control method for a core drill and a feed device for driving the core drill along a machine holding device, including the method steps: moving the core drill in a first direction; detecting the surface position of a material based on reaching a threshold value for at least one feed device parameter as a first reference value; moving the core drill in a second direction; operating the core drill in a tapping mode; moving the core drill in the first direction; detecting the surface position of a material based on reaching a threshold value for at least one corresponding drilling parameter as a second reference value; activating a water supply; and activating a regulating and control unit for adapting at least one drilling parameter as a function of at least one parameter of the feed device.

Abstract: A method of cleaning at least one collecting electrode of an electrostatic precipitator includes applying, in a first mode of operation, a first average current between at least one discharge electrode and at least one collecting electrode, and switching from the first mode of operation to a second mode of operation in which a second average current is applied between the at least one discharge electrode and the at least one collecting electrode, the second average current being a factor of at least 3 higher than the first average current, to achieve a forced cleaning of the at least one collecting electrode.

Abstract: A variable speed switch includes a switch main body portion which is accommodated in a housing of an electric power tool and mounted to the housing so as to be capable of relative movement, and a load sensor which is provided in the switch main body portion and capable of outputting an electric signal in proportion to the amount of distortion caused by a pressing force. The switch operating portion is mounted on the surface of the housing so as to be capable of relative displacement with respect to the housing and transmits a pressing force applied to the switch operating portion to the load sensor, with the maximum displacement amount of the switch operating portion being set to equal to or less than 5 mm.

Abstract: A variable speed switch includes a switch main body portion which is accommodated in a housing of an electric power tool and mounted to the housing so as to be capable of relative movement, and a load sensor which is provided in the switch main body portion and capable of outputting an electric signal in proportion to the amount of distortion caused by a pressing force. The switch operating portion is mounted on the surface of the housing so as to be capable of relative displacement with respect to the housing and transmits a pressing force applied to the switch operating portion to the load sensor, with the maximum displacement amount of the switch operating portion being set to equal to or less than 5 mm.

Abstract: Disclosed is a drilling and/or striking hammer that includes a lubricating device having a lubricant reservoir and a volume of lubricant contained therein. The lubricating device conveys lubricant to at least one a transmission system within the hammer's housing, a percussion system, and/or a tool holder at a variable dosing or flow rate. The dosing or flow rate varies as a function of tool stress which can include use intensity and/or temperature. A flexible tube extends between the reservoir and the lubricated component(s). At lease part of the flexible tube vibrates with the lubricated components during use and modifies a viscosity of the lubricant therein, based on tool use intensity. A pressure generating device can pressurize the lubricant, helping convey the lubricant to a targeted area for lubricating movable parts.

Abstract: In an earth drilling rig in which an air compressor and one or more hydraulic pumps are driven by the same engine, the intake throttle of the compressor is controlled by an electronic controller having a proportional integral derivative control. The controller minimizes unloading of the compressor, allowing the engine to operate more efficiently, the hydraulic system to provide more consistent power to drilling functions and the volume and pressure of compressed air to be optimized for the drilling conditions encountered. The electronic controller also operates a blowdown valve at the discharge side of an air receiver, and effects various overrides of the control system, for example when air discharge temperature approaches a critical level, or when an overpressure condition is detected.

Abstract: An apparatus and method is provided for substantially continuously drilling and disposing of drill cuttings and dust to minimize airborne contamination while providing protection against overload. A drill stem with a bit is advanced by a drill head to form the drill hole. A flushing mechanism utilizes vacuum or pressurized water for flushing the cuttings and dust from the drill hole for disposal. A transducer monitors the negative or positive gauge pressure. A controller is utilized to regulate the rate of drilling dependent on the signal level of the pressure being monitored. In the preferred embodiment utilizing air, the passage in the drill stem removes the cuttings/dust and is connected to a transfer duct, which in turn is connected to a filter and the intake side of a blower. The controller is programmable to establish the optimum rate of feed of the drill head. The rotary motion of the drill bit can also be regulated by the controller.

Abstract: A hydraulic impact tool for use in a well, such as an oil or gas well, comprising a movable hammer which is arranged to prestress a spring by means of a hydraulic piston (16) provided with a through channel (20), and in which a movable sealing body (22, 45) is arranged to enable closing of the channel (43), so that hydraulic force from fluid under pressure applied to the impact tool, may displace the piston (16) and the hammer and prestress the spring, and in which the sealing body (22) is arranged to follow the piston (16) into an end position for so to open the channel (20) for throughput, so that the hydraulic force acting on the piston (16, 41) ceases, and the prestressed spring is released and drives the hammer to strike, at the same time as the piston (16, 41) returns to initial piston, whereafter the process is repeated. The sealing body (22) is arranged to close said channel (20) when the sealing body is subjected to a predetemined frictional force from fluid flowing through the impact tool.

Abstract: A device for disabling the draw works of a well drilling apparatus responsive to the locking of the drill string by a blow out prevention device. The device comprises an air-actuated valve connected for regulating the flow of air to the air-actuated clutch of the draw works. A second valve regulates the flow of pressurized air to the air actuated valve. The second valve is responsive to the actuation of the blow out prevention device by an accumulator valve.

Abstract: A machine pre-start warning device comprises at least one water spray nozzle and at least one temperature dependent resistor, the or each temperature dependent resistor being located with respect to a nozzle as to lie in the water jet emitted in use by the nozzle. The temperature dependent resistor is connected to a control circuit to actuate the control circuit upon sensing a water jet which circuit enables machine start-up to occur when the circuit is actuated and which otherwise prevents start-up from occurring.

Abstract: A pneumatically operated stone-working tool has a tool drive, a spraying device for spraying the work area with a liquid and a control assembly for opening and closing the pneumatic line. The control assembly includes a valve plunger rotatably and linearly displaceably received in a chamber which is in the path of a pneumatic line feeding the tool drive and a liquid line feeding the spraying device. The plunger has a first linear position in which it maintains the pneumatic line closed regardless of the angular position of the plunger and a second linear position in which it maintains the pneumatic line open solely when the plunger is manually rotated into an "open" angular position. A force-exerting arrangement continuously urges the plunger towards its first linear position. The plunger has a work face so oriented that it is continuously exposed to a pressure of the liquid in that part of the chamber which is in communication with the liquid line.