| 摘要 |
A ratcheting electronic torque wrench (10) has an input beam in the form of a hollow housing (11) with a handle end (29) and a work end (28), a ratchet head (30) disposed within the work end of the housing and rotatable relative thereto and a reaction beam (35) disposed within the housing and having one end fixed to the ratchet head for pivoting therewith about the axis thereof and input end (37) resiliently urged to a neutral position relative to the housing by two bias springs (40, 41) respectively engaging opposite sides of the reaction beam. A Hall-effect sensor (47) carried by the input end of the reaction beam is disposed between two permanent magnets (48a) and is powered by a battery (42) for producing an output indicative of reaction beam movement, which is proportional to applied torque. A display circuit (60) can display the applied torque or a predetermined torque level set by a preset circuit. An alarm signal (87) is generated when the applied torque reaches the predetermined level.
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