Visual indicator

An indicator for sensing the degree of tension in a tensile member comprising in combination:

• first and second indicator elements, said elements being deformable in response to the application of an external force;
• first force application means to apply an external force to said first indicator element as a function of the tension applied to said tensile member;
• second force application means to apply an external force to said second indicator element as a function of the absence of tension in said tensile member;
• containment means parallel to the longitudinal axis of the tensile member and adjacent said first and second indicator elements, said containment means having a viewing area in an exterior side wall thereof;
• the relationship of said first and second indicator elements to said containment means being such that the application of tension to said tensile member causes an external force to be applied to said first indicator element with the result that said first indicator element is caused to be deformed thus presenting a change in optical appearance at said viewing area, the absence of tension in said tensile member causing an external force to be applied to said second indicator element with the result that said second indicator element is caused to be deformed thus presenting a change in optical appearance of said viewing area.

An indicator for sensing the degree of tension in a threaded member comprising in combiation:

• first and second generally elastomeric indicator elements, said elements having, in an undeformed state, a substantially circular cross section;
• first and second substantially annular retainer rings, said retainer rings being disposed substantially concentric with the axis of said threaded member;
• a substantially annular translucent containment wall parallel to the longitudinal axis of the tensile member and surrounding said first and second indicator elements and said first and second retainer rings;
• said first indicator element being disposed substantially between said first and second retainer rings, the relationship of said first indicator element to said first and second retainer rings being such that upon movement of said retainer rings toward one another said first indicator element is caused to be deformed in an essentially radial direction into contact with said containment wall;
• a nut engaging said threaded element, said nut being in operative engagement with at least one of said retainer rings whereby upon take-up of said nut said first and second retainer rings are moved toward one another thereby to deform said first indicator element;
• a bias spring operatively engaging at least one of said retainer rings, said bias spring exerting a bias opposite to that imparted to its associated retainer ring by said nut;
• means cooperating with at least one of said retainer rings to confine said second indicator element;
• whereby, the loss of tension in said threaded member results in said bias spring causing a movement of the retainer ring associated with said second indicator element producing deformation of said second indicator element, there being achieved a change in optical appearance of said second indicator element through said containment wall.