Abstract: A method is used for tightening screw joints by a power tool which includes a manually operated trigger for controlling power supply to the power tool, and a power shut-off mechanism for automatic discontinuation of the power tool operation as a predetermined tightening level is reached. The method includes continuously indicating a position of the trigger, indicating a status of the power shut-off mechanism, and disabling the power tool in an inoperative state for a predetermined time if the trigger is indicated as inactivated without the shut-off mechanism being indicated as activated.

Abstract: A pneumatic impulse wrench includes a housing with a motor powered impulse unit, a pressure air inlet passage, an exhaust air outlet passage located in the housing and connected to the motor, and a motor power controlling valve mechanism located in the exhaust air outlet passage for automatic control of the exhaust air flow from the motor. A control pressure passage extends between the air inlet passage and the valve mechanism for communicating actual air inlet pressure to the valve mechanism. An operating mode shifting valve is provided in the housing and which is shiftable between an open position in which communication is allowed through the control pressure passage in an automatic valve mechanism operating mode, and a closed position in which communication through the control pressure passage is blocked in a manual valve mechanism operating mode.

Abstract: A method for diagnosing a torque impulse generator which includes a rotational input portion, a torque output portion, an oil reservoir and a torque generating arrangement converting rotation of the input portion to torque impulses at the torque output portion, the method includes: detecting an acoustic signal from the torque impulse generator while generating torque impulses, extracting the frequency of torque impulses from the acoustic signal, and diagnosing the torque impulse generator based on the frequency of torque impulses, to indicate the level of oil in the oil reservoir.

Abstract: A torque delivering power tool includes a power line driven by a motor. The power line includes an input part with an input shaft, an output part with an output shaft, and at least one gear. The input shaft is drivingly connected to the output shaft via the gear. A motor shaft is drivingly connected to the input shaft via a reduction gearing. A torque meter monitors a torque acting in at least one point along the power line, an angle meter monitors an angular rotation in the power line, and an index meter monitors absolute angular positions of the input shaft or the output shaft. A control unit receives information from the angle meter, torque meter and index meter, and controls a torque output of the motor according to a mapping function corresponding to an angular index position dependent torque transmission over the power line.

Abstract: A displacement sensor for a power tool includes: a stator element, having a first conductive pattern, and a rotor element, having a second conductive pattern, for relative movement along a measurement path, wherein the first and second conductive patterns are mutually inductively coupled so that the first conductive pattern receives an excitation signal and the second conductive pattern generates an intermediate signal. The intermediate signal indicates relative displacement between the stator and rotor elements, wherein the excitation signal is a constant amplitude high-frequency signal. A signal processor circuit receives and processes a single phase receive signal corresponding to the intermediate signal to provide an output signal indicating relative displacement between the rotor and stator elements.

Abstract: A sensor unit for inducing and indicating ultra sonic sound waves in at least one threaded fastener by physical contact with an end surface thereof, wherein the sensor unit includes: a support casing, a sensor element with forward contact surface for engaging the fastener end surface and movable relative to the support casing between rest and active positions, and a bias spring between the support casing and the sensor element to urge the sensor element into the rest position as the sensor element is out of contact with the fastener end surface and to bias the contact surface of the sensor element into physical contact with the fastener end surface in the active position. The support casing includes a positioning socket, engaged by the sensor element in the rest position, having a non-cylindrical and non-circular cross sectional inner shape and congruent with an outer shape of the sensor element.

Abstract: A ratchet type power wrench includes a housing, a pressure medium powered actuator, a ratchet mechanism included in the housing and coupled to the actuator, an open ended output socket with a constant cross sectional dimension throughout a length thereof, which is rotatably supported in the housing and engaged by the ratchet mechanism, and an angle encoder provided to indicate angular displacements of the output socket. The angle encoder has a form of a separate unit included in a casing, the casing being attachable to either side of the housing for connecting the angle encoder to either end of the output socket. The angle encoder includes a rotatable signal initiating part and a movement sensor rigidly mounted in the casing, the rotatable signal initiating part being provided with at least one coupling dog adapted to engage cavities located at both ends of the output socket.

Abstract: An improved method and apparatus for creating a representation of transferred torque (?tr) over a rotation angle interval (?) for a torque transferring system wherein the torque transferring system includes at least two meshing gears, a torque meter for monitoring the transferred torque (?tr) in the torque transferring device, and an angular meter arranged to monitor an angular position (?) of at least one of the meshing gears over at least one angular interval (?int). Further, the system includes a processor that is adapted to: map the transferred torque (?tr) to the monitored angular interval (?int) and create a representation of the transferred torque (?tr) over said angular interval (?int), analyze said representation in order to identify deviations from an expected representation, and based on said analysis determining a gear condition of at least one of the at least two meshing gears in the torque transferring device.

Abstract: A method of verifying a magnitude of a delivered output torque during a tightening operation of a threaded joint performed by a hand held power wrench including a housing, a motor, an output shaft, and a power transmission connecting the motor to the output shaft. The method includes: tightening the threaded joint; monitoring a magnitude of a direct torque acting along the power transmission during the tightening by at least one direct torque indicating sensor; monitoring a magnitude of a reaction torque transferred via the housing during the tightening by at least one reaction torque sensor; comparing the monitored magnitude of the direct torque with the monitored magnitude of the reaction torque; and determining, based on the comparison, whether the accuracy of the delivered output torque is acceptable.

Abstract: A torque delivering power tool with a telescopically arranged output shaft includes a motor, a housing, an input shaft and an output shaft. A sensor is arranged to monitor an axial position of the output shaft with respect to the input shaft. The output shaft is telescopically arranged with respect to the input shaft between a fully extended position (PE) and a fully compressed position (PC). A resilient member having a known resilience in function of an extension is arranged to urge the output shaft towards the fully extended position (PE), such that the extension of the output shaft continuously reflects a compression force acting between the output shaft and the input shaft. An indication unit is arranged to indicate an axial compression force acting between the output shaft and the input shaft based on a level of extension between the shafts.

Abstract: A reversible pneumatic vane motor includes a stator housing with a pressure air inlet passage and an exhaust air outlet passage, a cylinder supported in the stator housing, a vane carrying rotor rotatable in the cylinder and forming a clearance seal portion with the cylinder, air communication ports located at opposite sides of the seal portion for supplying motive pressure air or scavenging exhaust air from the cylinder, a primary outlet diametrically opposite the clearance seal portion, and a directional valve for connecting alternatively the air communication ports to the pressure air inlet passage and the exhaust air outlet passage. The motor also includes auxiliary outlet ports which are located between the primary outlet and each one of the air communication ports, and the directional valve includes control parts for opening up and closing, respectively, communication between the auxiliary outlet ports and the atmosphere via the exhaust air outlet passage.

Abstract: The invention relates to an emergency stop device for a power tool comprising an electrical power contact for releasably connecting a power source to the power tool, and an emergency stop circuit connected to the electrical power contact and configured to disconnect the electrical contact from the electrical power source upon receipt of an emergency stop signal by the emergency stop circuit. The invention further relates to a power tool, a system comprising such a tool and a method of performing emergency stop of a power tool.

Abstract: A repositionable power wrench includes a housing, a motor arranged inside the housing, and an output shaft, which is rotationally connected to the motor and telescopically arranged with respect to the housing to allow axial movement of the output shaft with respect to the housing between a fully extended position (Emax) and a fully compressed position, with a resilient member being arranged to urge the output shaft towards the fully extended position (Emax). The power wrench also includes or is connectable to a positioning system arranged to monitor a position of the power wrench. The output shaft includes an output end arranged to interact with a fastener. A sensor is arranged to monitor a level of extension (E) of the output shaft with respect to the housing, such that the position of the output end of the output shaft may be determined.

Abstract: A pneumatic impulse wrench includes a motor, a housing with a pressure air inlet passage, an exhaust air outlet passage, and an air flow control valve provided in the exhaust air outlet passage and including a valve element shiftable between an exhaust air flow restricting position and an exhaust air flow non-restricting position. A rigid contact member is provided to positively define the exhaust air flow restricting position of the valve element, and a bypass passage of a well-defined flow area is provided to let through a limited exhaust air flow as the valve element occupies the flow restricting position in engagement with the contact member.