INSTRUCTION MANUAL TAPE EXTENSOMETER Model CONVEX-D Roctest Limited, 2013. All rights reserved. This product should be installed and operated only by qualified personnel. Its misuse is potentially dangerous. The Company makes no warranty as to the information furnished in this manual and assumes no liability for damages resulting from the installation or use of this product. The information herein is subject to change without notification. Tel.: 1.450.465.1113 • 1.877.ROCTEST (Canada, USA) • +33.1.64.06.40.80 (France) • +41.91.610.18.00 (Switzerland) www.roctest-group.com E1062D-27032013 TABLE OF CONTENTS 1 PRODUCT ...................................................................................................................................... 1 1.1 INTRODUCTION ..................................................................................................................... 1 1.2 TECHNICAL DESCRIPTION ................................................................................................... 1 1.2.1 PERFORATED MEASURING TAPE AND REEL .............................................................. 2 1.2.2 TENSION ADJUSTMENT KNOB ...................................................................................... 2 1.2.3 DIGITAL INDICATOR ....................................................................................................... 3 1.2.4 TENSION ADJUSTMENT MODULE ................................................................................. 3 1.2.5 REFERENCE POINTS ..................................................................................................... 4 2 INSTALLING REFERENCE POINTS ............................................................................................. 4 3 TAKING READINGS AND DATA COMPILATION ......................................................................... 5 3.1 TAKING READINGS ................................................................................................................ 5 3.1.1 SELECTING THE RIGHT INDEX HOLE ........................................................................... 6 3.1.2 SWITCHING INDEX HOLE ............................................................................................... 8 3.1.3 TENSIONING ADJUSTMENTS ........................................................................................ 8 3.1.4 DIGITAL INDICATOR ....................................................................................................... 9 3.2 DATA COMPILATION ............................................................................................................. 9 3.2.1 TEMPLATE FOR DATA COMPILATION .......................................................................... 9 3.2.2 DETAILED EXAMPLE FOR DATA COMPILATION .......................................................... 9 3.3 TEMPERATURE CORRECTIONS ........................................................................................ 11 4 MAINTENANCE ........................................................................................................................... 12 4.1 CLEANING AND LUBRICATION ........................................................................................... 12 4.2 VERIFICATION FRAME ........................................................................................................ 12 4.3 BATTERY REPLACEMENT .................................................................................................. 12 5 MISCELLANEOUS ...................................................................................................................... 13 5.1 CONVERSION FACTORS ..................................................................................................... 13 5.2 TEMPLATE FOR FIELD DATA SHEET ................................................................................ 14 E1062D-27032013 E1062D-27032013 CONVEX-D 1 PRODUCT 1.1 INTRODUCTION The CONVEX-D is a digital tape extensometer which quickly and accurately measures changes in distance between two reference points in any orientation. This design incorporates several improvements compared to other convergence instruments available on the market. 1.2 TECHNICAL DESCRIPTION The whole system comprises the following components: CONVEX-D MAIN COMPONENTS (Tape reel not shown) Page 1 E1062D-27032013 CONVEX-D 1.2.1 PERFORATED MEASURING TAPE AND REEL A perforated measuring tape is housed into a reel that is attached to the anchor block located on the main body. The tape is graduated in meters, centimeters and millimeters on one side, and in feet and inches on the other side. The index hole close to each two inches increment is imperial and the index hole closer to each 50 mm is metric. 1.2.2 TENSION ADJUSTMENT KNOB A tension adjustment knob is used in combination with a tension adjustment module in order to allow the user apply a constant and repetitive tension on the tape when alignment marks are aligned. The adjustment knob has a unique anti- backlash tensioning mechanism ensuring a continuous accuracy in time. Page 2 E1062D-27032013 CONVEX-D 1.2.3 DIGITAL INDICATOR A digital indicator has also been added in order to accurately read the relative change between two reference points. By turning the rotary protection drum, it is easy to get quick access to the digital indicator function keys through the opening provided for this purpose. ACRYLIC WINDOW In operation mode, the rotary protection drum is turned in such a way that the digital indicator is still readable but protected by a small acrylic window. 1.2.4 TENSION ADJUSTMENT MODULE The tension adjustment module comprises: ALIGNMENT MARK’S MAGNIFYING MODULE A pivoting latch, to lock positively the tape, thus facilitating the instrument's handling. PIVOTING LATCH Alignment mark’s magnifying module to optimize the visual alignment with two superimposed magnifying lenses. Page 3 E1062D-27032013 CONVEX-D 1.2.5 REFERENCE POINTS The standard reference point consists of a stainless steel eyebolt attached to an anchor. The anchors, chosen to suit the application, are either groutable steel rebar anchors for installation in shallow drill holes, or expanding rock anchor bolts. The eyebolts can also be directly bolted or welded to structural steel beams. 2 INSTALLING REFERENCE POINTS A good anchoring of the reference points is required to reach the specified instrument accuracy. In soft fissured rocks and masonry, grouted anchors are recommended (Type A – Refer to illustration from section 1.2.5). They are installed in drilled holes with a minimum diameter of 20 mm and a minimum length of 150 mm. The rebar anchor is grouted in the hole with an epoxy resin or a non-shrinking cement grout. For hard rocks and concrete, it is possible to use the expanding rock anchor bolts (Type B – Refer to illustration from section 1.2.5). They are installed in a drilled hole with a minimum diameter of 13 mm and a minimum length of 35 mm. The rock bolts are secured by tightening down the bolt. The eyebolts must be locked in place with the lock nut against the head of the bolt or anchor. The precise alignment of the reference points is not required, since the tape extensometer can be used at an angle to the axis of the reference points. Page 4 E1062D-27032013 CONVEX-D 3 TAKING READINGS AND DATA COMPILATION 3.1 TAKING READINGS Although simple, the CONVEX-D requires a standard procedure in order to obtain reliable and precise measurements. The procedure below explains all the steps to achieve consistent measurements. 1. Reset (screw) the tension adjustment knob all the way in until the end stop is reached (screw the knob towards digital indicator). 2. Turn the rotary protection drum to access the digital indicator. Press the “ON” key (ON/OFF). Set the units (mm/inch). 2.1. This sub-step is optional and should only be achieved when the zero set point has previously been altered. Press the "ZERO" key to reset the digital indicator to zero value (i.e. when the tension adjustment knob is completely screwed and has reached its end stroke). Note: Make sure the "ABS" key has not been pressed before trying to reset the "ZERO", otherwise it will not be possible to reset the zero without pressing again the "ABS" key. To check if the "ABS" key has previously been enabled, make sure the mention "INC" does not appear in the top left corner of the digital indicator. 3. Unscrew the tension adjustment knob (towards the reel) to its proper initial position, which have been pre-established according to the anticipation of movement direction (refer to the figure in section 3.1.1). 4. Flip the crank handle to unlock the reel. Release the tape by unlocking the pivot lock. 5. Secure the snap hook of the CONVEX-D tape to the first reference point. Carry the CONVEX-D towards the opposing reference point and secure the reel hook. Be careful not to bend or twist the tape to avoid false readings. 6. Wind the tape back with the crank to remove the sag and then pull the tape to insert the tightest index hole into the index pin without preloading the tensioning device. Secure the tape by closing the pivot lock. Refer to section 3.1.1 for detailed instructions on how to select the right index hole. Page 5 E1062D-27032013 CONVEX-D 7. Hold the main body of the CONVEX-D with one hand and rotate the tension adjustment knob with the other hand until the tension reference marks are aligned. Slightly move the CONVEX-D nose up and down a few times to balance the tensioning device and eliminate hysteresis. Readjust the tension marks with the tension adjustment knob if