A strain indicator of the type wherein a change in length of a strain member produces movement of an indicator member. Such movement, in the elastic range of the fastener material, is essentially linear and in proportion to the stress being applied to the fastener. When, however, a preset strain limit within the fastener is exceeded the indicator element is biased in an upward direction giving an immediate visual indication of that fact.
An optical indicator of the type wherein the lessening of the load on a member under strain produces movement of an indicator element. Such movement takes place when the relaxation of the member under strain has reached a certain predetermined value thereby giving an immediate visual indication of that fact.
A bolt for attaching a first member to a second with a desired compressive force. The bolt has a cylindrical body with a threaded section on a first end and a head on a second end. The cylindrical body had a longitudinal bore which extends to a cross bore in the head. A pin located in the cross bore has a first flat surface separated from as second flat surface by a shoulder. A rod located in the longitudinal bore has a first end fixed to the cylindrical body and a second end that is located on the first flat surface. A spring acts on the pin to hold the shoulder against the rod. An input torque applied to the head causes the threads to move into threads on the second body. When the head engages the first body, further torque results in expansion or elongation of the cylindrical body. The rod freely moves in the longitudinal bore and when a predetermined elongation occurs corresponding to the depth of the shoulder on the pin, the spring moves the pin to align the second flat surface over the rod. With the second flat surface in alignment with the rod, a portion of the pin extends past the head to provide a visual indication that a desired compressive force has been developed between the first and second members.
A coating thickness gauge for measuring the thickness of a coating of chromic oxideon a chromium layer on a substrate has a light source 17 for generating linearly polarized light, means 19 for splitting elliptically polarized light reflected through the chromic oxide coating into a plurality of beams 20, 21, detectors 22, 23 for intensity of each of the beams and means 24 for calculating the thickness of the coating of chromic oxide from the measured intensities. To simplify the device and the calculation, the splitting means are arranged to split the reflected elliptically polarized light into two partial beam 20, 21 polarized at a known angle relative to each other and the calculation means calculate the ellipticity from the measured intensity of the two partial beams and the thickness from the ellipticity.
An anchoring device for a tension member of an earth- or rock anchor, where a support element transmitting the tensile force is arranged between an anchoring element undisplaceably connected with the tension member and an anchor plate abuttable against a support base, the support element includes a cylindrical hollow body surrounding the anchoring element, whose inner wall has in its lower region projections protruding inward beyond its inner contour, against which the anchoring element abuts in a force-transmitting manner with partial regions of its cross-sectional area. If a predetermined tensile force is exceeded, the support element and/or the anchoring element can plastically deform in the region of their inter-engaging surfaces, so that a relative displacement occurs in axial direction. Distance or spacer pins are provided in a head plate placed upon the tension member for visual indication of the relative displacement, which after contact with the surface of the hollow body exit upwards from the head plate.
An installation and retainer cap is disclosed for making a secure connection between an annular internally splined collar member and an externally splined shaft end. The cap includes a cap body, a threaded driving shaft extending from the inner side of the body engaging a threaded bore in the end of the shaft, and an outer flange engaging the annular collar member. When the cap is driven in to make the completed connection, the outside face of the flange is substantially flush with the outside face of the annular collar member. Recesses are provided in the end of the shaft and in the outside face of the annular collar member to accommodate the body and the flange, respectively. A washer cooperating with the outer flange allows relative turning movement during the driving of the collar into position. An indicator pin provides an indication when the annular collar is fully installed on the shaft. An alternative embodiment utilizing a separate cap and driving bolt is also disclosed.
