Stress indicating mechanical fastening device

• US 3,224,316 A
• Filed: 09/06/1963
• Issued: 12/21/1965
• Est. Priority Date: 09/06/1963
• Status: Expired due to Term

• Current Assignee: Henry W. Grikscheit, Robert H. Schott
• Original Assignee: Henry W. Grikscheit, Robert H. Schott
• Inventors: Grikscheit, Henry W., Schott, Robert H.
• Application Number:
  US04/307,242
• Time in Patent Office: 837 Days
• US Class Current: 411/13
• CPC Class Codes: F16B 31/02 for indicating the attainment of a particular tensile load or limiting tensile load apparatus for, or method of, determining value of torque or twisting moment for tightening a nut or other member similarly stressed G01L5/24
• CPC Class Codes: F16B 31/024 with the bottom of the nut or of the head of the bolt having gaps which close as the bolt tension increases, e.g. with lips or with a load-indicating flange

Claims

1. A TORQUE INDICATING FASTENING DEVICE COMPRISING A BODY HAVING AN INTERNALLY THREADED OPENING FOR SECUREMENT TO OTHER STRUCTURE, SAID BODY HAVING AN UPPER END SURFACE AND A LOWER END SURFACE, SAID BODY HAVING AN ANNULAR RECESS CONCENTRIC WITH THE INTERNALLY THREADED OPENING, SAID RECESS EXTENDING FROM THE UPPER END SURFACE TOWARDS THE LOWER END SURFACE AND DEFINING AN OUTER WALL PORTION AND AN INNER WALL PORTION, THE BODY MATERIAL BETWEEN THE BOTTOM OF THE RECESS AND THE LOWER END SURFACE HAVING A PREDETERMINED CROSS-SECTIONAL AREA TO RESULT IN A PREDETERMINED STRESS YIELD POINT, AND A STRESSSENSITIVE MATERIAL IN THE RECESS IN INTIMATE CONTACT WITH THE SURFACES DEFINING THE RECESS, SAID STRESS-SENSITIVE MATERIAL BEING REACTIVE TO RELATIVE MOVEMENT OF THE AFOREMENTIONED OUTER WALL PORTION AND INNER WALL PORTION OF THE BODY TO INDICATE THE OCCURRENCE OF SUCH RELATIVE MOVEMENT, RELATIVE MOVEMENT OCURRING WHEN THE TORQUE APPLIED TO THE BODY REACHES THE STRESS YIELD POINT OF THE BODY MATERIAL BETWEEN THE BOTTOM OF THE RECESS AND SAID LOWER END SURFACE.