ASME B107.300-2021 pdf download
ASME B107.300-2021 pdf download.Hand Torque Tools and Torque Testers.
5.1.3 Type II — Setting (a) Operation. Instruments shall sense torque trans- mitted by comparing the torque applied with a self- contained standard. The transmission of the preselected value shall be indicated by a physical impulse, with or without audible signal, which shall cause a temporary reduction in the applied torque. Operation shall be such as to minimize abrupt over-travel. Reset shall be automatic upon release of load application. (b) HandPosition. If,toachievetherequiredaccuracy,it is necessary to apply the load at a specific location on the handgrip other than the center, the handgrip shall be so designed or marked. (c) Auxiliary Functions. Additional features may be incorporated in the torque instrument to improve accu- racyorusefulness. The inclusion ofsuch features shall not becauseforrejectionofthetorqueinstrument,providedit otherwise conforms to the requirements ofthis Standard. (d) TypeII, ClassA—Graduated. Agraduatedscalewith increments appropriately numbered shall be located on the instrument and positioned as to permit convenient reading. Selection of the desired torque value shall be made by manual means, using a handgrip, and shall not require a separate tool or implement. Provision shall be made to accurately indicate the selected torque value on the graduated scale. A suitable portion ofthetorqueinstrumentgripshallbedesignedtofacilitate turningoftheadjustableportionofthegrip.Meansshallbe provided to protect the torque setting from accidental changes and shall not require a separate tool or imple- ment. Graduated setting type torque instruments may be similar to those shown in Figures 5.1.3-1 and 5.1.3-2.
(h) Type II, Classes A and B, Style 3 — Interchangeable Head Connection for Adapters and Extensions. The torque instrument shall be equipped with a connection, suitable for accepting a variety of mating wrenching heads. The connection and standard wrenching heads shall be designed so that the requirements of para. 5.10 are met throughout the specified accuracy range. The wrenching heads shall comply with the requirements of para. 5.7.4. Setting torque instruments with an inter- changeable head may be similar to that shown in Figure 5.1.3-5. (i) Type II, Classes A and B, Style 4 — Flexible Ratchet Head. Aflexible jointshall be providedto allowthe bodyto flex about an axis that is in a plane perpendicular to the axis ofthe drive tang and perpendicular to the axis ofthe body (see Figure 5.1.3-6). Flex angle shall be limited to an amount that will contain the induced torque accuracy error, including the instrument tolerance error to within the accuracy specified in para. 5.10. A mechanism shall be provided to maintain the ratchet head under its own weight in one or more positions, including one that places thedriveaxis perpendicularto the longitudinalaxis of the instrument. The ratchet shall comply with the re- quirements of para. 5.7.2.
5.1.4 Type III — Limiting (a) Operation. Limiting torque instruments shall operate by releasing the drive tang at the preselected torque value followed by automatic reset. The release and reset sequence shall occur a minimum of two times in one full revolution of the drive. The reset action should not cause a reverse torque (backlash), which might loosen the fastener being tightened. (b) TypeIII, ClassA —ScrewdriverGrip. The instrument shall be in a screwdriver configuration. The full scale setting of Type III, Class A instruments shall not exceed 40 lbf-in. (4.5 N·m). NOTE: This limitation is for safety reasons. (1) TypeIII, ClassA, Style1 —Graduated. Agraduated scale with increments appropriately numbered shall be locatedontheinstrumentandpositionedto permitconve- nient reading. Selection ofthe torque value shall be made by manual means not requiring a separate tool or imple- ment. Provision shall be made to accurately indicate the selected torque value on the graduated scale. The adjust- ment means shall be adequately protected against acci- dental change by an appropriate device or lock not requiring a separate tool or implement. The instrument may be similar to that shown in Figures 5.1.4-1 and 5.1.4-2.
