Bolt or nut tightening device

• US 7,757,587 B2
• Filed: 10/25/2007
• Issued: 07/20/2010
• Est. Priority Date: 10/30/2006
• Status: Active Grant

• Current Assignee: Maeda Metal Industries, Ltd.
• Original Assignee: Maeda Metal Industries, Ltd.
• Inventors: Hirai, Tatsuo, Kaneyama, Yasunobu
• Primary Examiner(s): Shakeri; Hadi
• Application Number:
  US11/924,109
• Publication Number:
  US 20080098863A1
• Time in Patent Office: 999 Days
• Field of Search: 81/571.4, 81/55, 81/571.3, 81/573, 81/573.1, 81/572.2, 81/573.9, 814/67, 814/79
• US Class Current: 81/57.14
• CPC Class Codes: B23P 19/066 by electrical means
• CPC Class Codes: B25B 17/02 providing for torque amplification
• CPC Class Codes: B25B 23/0078 Reaction arms
• CPC Class Codes: B25B 23/14 Arrangement of torque limiters or torque indicators in wrenches or screwdrivers couplings for transmitting rotation or clutches F16D; devices for measuring torque per se G01L

Abstract

A bolt or nut tightening device has an outer shaft and an inner shaft rotatable in directions opposite to each other, the outer shaft having a reaction receiver projecting therefrom sideways, the inner shaft being provided with an engaging portion engageable with a bolt or nut to be tightened, the bolt or nut tightening device being provided on the outer shaft with a tightening torque measuring unit, which comprises a strain sensor, a circuit board, an indicator, a battery, and a case for accommodating the circuit board, the indicator and the battery, the case being attached to the outer shaft, projecting toward the same direction as the reaction receiver, and being so sized as to be hidden by a contour of the reaction receiver and so positioned as to be hidden behind the reaction receiver when seen from the forward end side of the engaging portion.

Claims

1. A bolt or nut tightening device comprising the combination of a tightening assisting unit having an outer shaft and an inner shaft coupled to a planetary gear mechanism coaxially therewith and rotatable in directions opposite to each other, the outer shaft having a reaction receiver projecting therefrom sideways, the inner shaft being provided with an engaging portion engageable with a bolt or nut to be tightened, and input means coupled to the planetary gear mechanism, the outer shaft being provided with a tightening torque measuring unit, the tightening torque measuring unit comprising a strain sensor provided on the outer shaft, a circuit board for converting the amount of strain of the outer shaft as detected by the strain sensor to an amount of tightening torque, an indicator for indicating the amount of tightening torque, a battery, and a case for accommodating the circuit board, the indicator and the battery, the case being attached to the outer shaft and projecting toward the same direction as the reaction receiver, the case being so sized as to be hidden by a contour of the reaction receiver and being so positioned as to be hidden behind the reaction receiver when seen from the forward end side of the engaging portion;

wherein the case is rotatable about a rod orthogonal to an axis of the outer shaft.

2. The bolt or nut tightening device according to claim 1 wherein the indicator is located orthogonal to the outer shaft.