| 摘要 |
The wrench includes a handle 1 for applying torque through a shaft 2 to a working head 3. The shaft includes torque sensing means 10, 11 for calculating the torque applied to a work piece by the working head. A trigger mechanism (30, 40, Figures 5, 8) is 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 includes a permanent magnet 31, 41 that is normally anchored by magnetic attraction to a pole piece (12, Figure 5) so as to resist separation when a force is applied through the handle 1. A magnetic means 34, 44 is actuable to reduce or cancel that magnetic attraction so as to permit separation of the pole piece and permanent magnet when the set point is sensed by the torque sensing means. The separation of the pole piece and permanent magnet is accompanied by the small movement of the handle relative to the working head. The magnetic means 34, 44 may include electromagnetic coils wound around legs of a U-shaped permanent magnet. |
