| 摘要 |
A bolt or nut tightening device comprises the combination of input means (9) and a tightening assisting unit (1) having an outer shaft (4) and an inner shaft (3) coupled to a planetary gear mechanism (2) coaxially therewith and rotatable in directions opposite to each other, the outer shaft (4) having a reaction receiver (6) projecting therefrom sideways, the inner shaft (3) being provided with an engaging portion (6) engageable with a bolt or nut to be tightened. The outer shaft (4) is provided with a tightening torque measuring unit (7), which comprises a strain gauge (71) or like strain sensor (71a) provided on the outer shaft (4), a circuit board (72) for converting the amount of strain of the outer shaft (4) as detected by the strain sensor (71a) to an amount of tightening torque, an indicator (73) for indicating the amount of tightening torque, a battery (74), and a case (75) for accommodating the circuit board (72), the indicator (73) and the battery (74). The case (75) is attached to the outer shaft (4), projects toward the same direction as the reaction receiver (5), is so sized as to be hidden by a contour of the reaction receiver (5) and is so positioned as to be hidden behind the reaction receiver (5) when seen from the forward end side of the engaging portion (6). |
