Abstract: An electronic click wrench comprises a handle for applying torque through a shaft to a working head. The shaft includes torque sensing means for calculating the torque applied to a workpiece by the working head, and a trigger mechanism for sending a haptic feedback to a user by triggering a small movement of the handle relative to the working head when a set point torque is reached. The trigger mechanism comprises a permanent magnet that is normally anchored by magnetic attraction to a pole piece so as to resist separation when a force is applied through the handle, and an electromagnetic means actuable to reduce or cancel that magnetic attraction so as to permit separation of the pole piece and permanent magnet, thus generating the haptic feedback. Operation of the electromagnet may oppose the flux of the permanent magnet through the pole piece. Alternatively operation of the electromagnet may divert the flux of the permanent magnet away from the pole piece.

Abstract: An electronic click wrench comprises a handle for applying torque through a shaft to a working head. The shaft includes torque sensing means for calculating the torque applied to a workpiece by the working head, and a trigger mechanism for sending a haptic feedback to a user by triggering a small movement of the handle relative to the working head when a set point torque is reached. The trigger mechanism comprises a permanent magnet that is normally anchored by magnetic attraction to a pole piece so as to resist separation when a force is applied through the handle, and an electromagnetic means actuable to reduce or cancel that magnetic attraction so as to permit separation of the pole piece and permanent magnet, thus generating the haptic feedback. Operation of the electromagnet may oppose the flux of the permanent magnet through the pole piece. Alternatively operation of the electromagnet may divert the flux of the permanent magnet away from the pole piece.

Abstract: The invention provides a variable torque-rate test joint for the performance testing of rotary tools for threaded fasteners. In a typical test routine a nut is repeatedly tightened by the tool and after each tightening the nut must be released and run back to its start position. The invention provides a means for rapidly releasing the pressure on the tightened nut so that it can be run back quickly and easily. The variable joint is supported by a reaction surface that is the operative face of a piston and cylinder assembly seated on a shoulder fast to a shank of the threaded fastener. A hydraulic control is provided for the piston and cylinder assembly including means for hydraulically extending the piston from the cylinder to a fixed maximum extension which defines a test position of the reaction surface, and means for hydraulically retracting the piston back into the cylinder to remove the pressure from the nut at the end of the test.

Abstract: In a variable torque rate test joint, screw-threaded first and second elements are rotated relative to one another by a tool under test. At least one spring beam is cantilevered over a pivot point to exert an axial force between the first and second elements and the torque rate of the test joint can be varied by moving the pivot point to change the axial force. The first element may be a shaft that is fixed during testing and the second element is a nut rotatably mounted on the shaft, whereby the element rotated by the tool has a minimal moment of inertia. Whichever of the first and second elements is held stationary during the test may be mounted in a hub that is locked during the test but can be rotated at the end of the test to reset the test joint. Measurements may be made of the torque and the rotation angle to derive an actual torque rate of the joint, which allows correction of errors by moving the pivot point.

Abstract: In a variable torque rate test joint, screw-threaded first and second elements are rotated relative to one another by a tool under test. At least one spring beam is cantilevered over a pivot point to exert an axial force between the first and second elements and the torque rate of the test joint can be varied by moving the pivot point to change the axial force. The first element may be a shaft that is fixed during testing and the second element is a nut rotatably mounted on the shaft, whereby the element rotated by the tool has a minimal moment of inertia. Whichever of the first and second elements is held stationary during the test may be mounted in a hub that is locked during the test but can be rotated at the end of the test to reset the test joint. Measurements may be made of the torque and the rotation angle to derive an actual torque rate of the joint, which allows correction of errors by moving the pivot point.

Abstract: A variable torque-rate test point for the performance testing of rotary tools for threaded fasteners comprises a screw-threaded bolt (1) having a moment of inertia comparable to that of a bolt to be tightened using the rotary tool. The bolt (1) is tightened in the test joint against a torque-rate adjustment device (6) which can be adjusted to simulate a hard or a soft joint. The adjustment device (6) comprises a washer portion (7) beneath the bolt head (4), at least one spring beam (8) extending from a reaction point (9) radially outwardly of the bolt (1), and a pivotal bearing member (10) or other pivot at a mid portion of the beam (8). The beam (8) flexes as it extends in cantilever over the pivot point, and that flexure can be adjusted to vary the torque-rate of the test joint by varying the distance between the pivot point and the rotary axis of the bolt (1).

Abstract: The invention provides a variable torque-rate test joint for the performance testing of rotary tools for threaded fasteners. In a typical test routine a nut is repeatedly tightened by the tool and after each tightening the nut must be released and run back to its start position. The invention provides a means for rapidly releasing the pressure on the tightened nut so that it can be run back quickly and easily. The variable joint is supported by a reaction surface that is the operative face of a piston and cylinder assembly seated on a shoulder fast to a shank of the threaded fastener. A hydraulic control is provided for the piston and cylinder assembly including means for hydraulically extending the piston from the cylinder to a fixed maximum extension which defines a test position of the reaction surface, and means for hydraulically retracting the piston back into the cylinder to remove the pressure from the nut at the end of the test.

Abstract: A variable torque-rate test point for the performance testing of rotary tools for threaded fasteners comprises a screw-threaded bolt (1) having a moment of inertia comparable to that of a bolt to be tightened using the rotary tool. The bolt (1) is tightened in the test joint against a torque-rate adjustment device (6) which can be adjusted to simulate a hard or a soft joint. The adjustment device (6) comprises a washer portion (7) beneath the bolt head (4), at least one spring beam (8) extending from a reaction point (9) radially outwardly of the bolt (1), and a pivotal bearing member (10) or other pivot means at a mid portion of the beam (8). The beam (8) flexes as it extends in cantilever over the pivot point, and that flexure can be adjusted to vary the torque-rate of the test joint by varying the distance between the pivot point and the rotary axis of the bolt (1).

Abstract: An apparatus for celibrating rotary power assembly impulse tools comprises a variable rate simulated test joint in which a rotary shaft is braked by brake shoes in direct contact with the shaft under the control of a computer. The braking torque applied to the shaft by the brake shoes is gradually increased while the shaft is driven at free-running speed by the tool being calibrated, and the pulsed output of the impulse tool is monitored. The monitored pulsed output is initially erratic, but settles down to a regular stream of output pulses. The first pulse of that regular stream can be identified. The magnitude of the braking torque is then increased as a linear function of time with a predefined gradient representative of the torque rate of the joint being simulated, commencing with the identified first pulse. The apparatus is the first such apparatus to be able to provide thoroughly reliable and consistent torque calibration for impulse tools.