creator Liber, Theodore Fasteners such as mine bolts are provided with tension indicators to directly read tension in the shank of the bolt. The preferred tension indicators comprise an elongated pin disposed in a bore formed in the bolt and connected at the bottom of the bore to the bolt shank to be tensioned thereby. The tension indicator further comprises a cross bar attached to the other end of the pin and extending laterally into engagement with another portion of the bolt, such as the head of the bolt, to be bent upon tensioning of the pin. Preferably, a photoelastic member is attached to the cross bar and bending stresses in the cross bar are manifested in the photoelastic member in the form of photoelastic fringes for reading by a reflection polariscope. Submitted by Aric Ahrens (ahrens@iit.edu) on 2011-11-11T18:58:53Z No. of bitstreams: 1 3823639.pdf: 218496 bytes, checksum: f56e355aa69d94e480fe7438c0100e68 (MD5) Made available in DSpace on 2011-11-11T18:58:53Z (GMT). No. of bitstreams: 1 3823639.pdf: 218496 bytes, checksum: f56e355aa69d94e480fe7438c0100e68 (MD5) Previous issue date: 1974-07-16 IIT Research Institute 2009-03-04 1974-07-16 3,823,639 http://hdl.handle.net/10560/2318 en United States Patent Patent reformatted digital application/pdf No Copyright - United States http://rightsstatements.org/page/NoC-US/1.0/ Open Access