ASME B107.300-2010 pdf download.Torque Instruments.
1 SCOPE This Standard provides performance and safety requirements for manuallyoperated torque instruments, commonly used for mechanical measurement of torque for control of the tightness of threaded fasteners. It is not intended to describe products infrequently utilized or those designed for special purposes. This Standard may be used as a guide bystate authori- ties or other regulatory bodies in the formulation oflaws or regulations. It is also intended for voluntary use by establishments that use or manufacture the instruments covered. 2 CLASSIFICATION 2.1 Type I: Indicating Class A: deflecting beam Style 1: plain scale Style 2: scale with signal mechanism Style 3: scale with memory indicator Class B: deflecting beam with interchangeable head connection Style 1: plain scale Style 2: scale with signal mechanism Style 3: scale with memory indicator Class C: rigid housing Style 1: plain scale Style 2: scale with signal mechanism Style 3: scale with memory indicator Class D: rigid housing with interchangeable head con- nection Style 1: plain scale Style 2: scale with signal mechanism Style 3: scale with memory indicator Class E: screwdriver grip Style 1: enclosed dial Style 2: exposed dial 2.2 Type II: Setting Class A: graduated Style 1: nonratcheting Design A: clockwise (right-hand) and counter- clockwise (left-hand) torquing Design B: clockwise torquing Design C: counterclockwise torquing Style 2: ratcheting Design A: clockwise (right-hand) and counter- clockwise (left-hand) torquing
3 REFERENCES The following documents form a part of this Standard to the extent specified herein. The latest edition shall be used. ASME B107.4, Driving and Spindle Ends for Portable Hand, Impact,Air,and Electric Tools (PercussionTools Excluded) ASME B107.10, Handles and Attachments for Hand Socket Wrenches ASME B107.29, Electronic Tester, Hand Torque Tools Publisher: The American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016-5990; Order Department: 22 Law Drive, Box 2300, Fairfield, NJ 07007-2300 (www.asme.org) Guide to Hand Tools — Selection, Safety Tips, Proper Use and Care Publisher: Hand Tools Institute (HTI), 25 North Broadway, Tarrytown, NY 10591 (www.hti.org) 4 DEFINITIONS accuracy: the permissible deviation, tolerance, or error band. A higher value means a lower certainty of correctness. full scale: see rated capacity. graduation: a mark on the instrument indicating a torque value. hand torque instrument: tool combining hand wrenching and torque measurement functions, formerly referred to as “hand torque wrench.” increment: the value of the difference between adjacent graduations. indicated value: for Type I, the value the instrument dis- plays when torque is applied; for Types II and III, the value to which the instrument is set or preset. measured value: the actual torque determined by a torque tester. operating load: the operating load shall be calculated by dividing the rated capacity by the distance between the axis of the torque moment and the center of the grip or designated load point. rated capacity: for graduated instruments, the maximum graduated torque value, also known as full scale; for nongraduated instruments, the maximum manufac- turer-specified torque. scale: the representation of the range of the instrument, divided into increments marked by numbered and unnumbered graduations. setting: the amount of torque the instrument is expected to apply.
5 REQUIREMENTS Figures 1 through 20 are descriptive and not restric- tive. They are not intended to preclude the manufacture or purchase of other forms of torque instruments con- forming to this Standard. Torque Instruments shall pass all applicable tests in section 6. 5.1 Design 5.1.1 Type I, Classes A, B, C, and D — Indicating (a) Operation. Instruments shall indicate torque applied through a deflectingmember. They shall operate in both clockwise and counterclockwise directions. (1) TypeI, Classes A andB —DeflectingBeam. Flexing of a cantilever beam connecting the square drive and the hand grip shall provide the basis ofoperation. Type I, Class A deflecting beam torque instruments may be sim- ilar to that shown in Fig. 1. Type I, Class B deflecting beam torque instruments may be similar to that shown in Fig. 2. (2) Type I, Classes C and D — Rigid Housing. The deflecting member and dial mechanism shall be enclosed within the rigid housing. The pointer and dial face shall be protected by a transparent cover which shall be so located and constructed as to be reasonably free from accidental damage resulting from being struck or abraded. Type I, Class C rigid housing torque instru- ments may be similar to that shown in Fig. 3. Type I, Class D rigid housing torque instruments may be similar to that shown in Fig. 4.