BS 7996:2009 pdf free.Torque measuring devices—Calibration and classification using continual torque application – Method.
BS 7996 This British Standard specifies a method for the calibration and classification of torque measuring devices using continuous torque application where the inertial effects are minimal. This includes torque measuring devices used for the calibration of hand torque tools conforming to BS EN ISO 6789, and torque measuring devices conforming to BS 7882.
The information to be given on the certificate of calibration is also specified in this standard.
Annex A provides diagrams of the continuous application of torque, and examples for the calibration of torque measuring devices. Annex B gives an example of determining uncertainty of the calibration results of the torque measuring device. Annex C shows how to calculate mechanical and electronic bandwidth.
Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
BS 7882, Method for the calibration and classification of torque measuring devices
BS EN ISO 6789, Assembly tools for screws and nuts – Hand torque tools – Requirements and test methods
JCGM 200, International vocabulary of metrology — Basic and general concepts and associated terms (VIM) (third edition available at: http:ll www.bipm.org/utilsIcommonIdocuments1jcgmIJCGM_200_20O8.pdf)
data skew change in applied torque during the period between nominally synchronized readings from the reference standard and the torque measuring device
NOTE This period can be due to the readings being taken at different times or propagation delays. It can be determined, at various stable torque values throughout the torque calibration range, by applying a sharp mechanical stimulus to the system and measuring the difference in response times of the outputs from the reference standard and the torque measuring device.
deceleration period time interval during which the rate of change of applied torque decreases from a constant value to zero
deflection algebraic difference between the indicator reading prior to the application of a torque and the indicator reading for each applied torque in a given measurement series
NOTE The deflection may be derived from either digital data output or visual data output.
loading direction direction of applied torque, either clockwise or anti-clockwise about the axis of rotation, when viewed from the end of the torque measuring device to which the calibration torque is applied.BS 7996 pdf download.