Encardio-rite model EDS-80 tape extensometer measures the relative displacement which takes place with time between reference anchors fixed to an excavation or a structure.
The tape extensometer is designed to accurately measure small change in distance between two points which may be from 1 m to 30 m (or 50 m) apart. It can be used in any orientation.
Description:
Model EDS-80 tape extensometer consists of a precision punched tape, incorporating a repeatable tensioning system and a digital read-out, which are housed in an instrument casing (1). A shackle (3) is fixed to one end of the instrument casing. Another shackle (3) is fixed to the free end of the tape measure (2).
To obtain a reading, the shackle on the instrument casing is hooked to one of the anchor bolts firmly grouted to the structure. The tapemeasure is unwound, allowing the shackle on its end to hook into the anchor bolt on the opposite side. Constant tension in the tape is achieved by a precision tension spring and a knurled adjustment knob. This permits the measurement to be made with a minimum of sag (which is repeatable) over a variety of distances in the horizontal, inclined or vertical directions.
For taking readings, the tape and digital readings are noted. The fine reading from the digital display is added to the coarse reading from the tape. The variation from the original reading, gives the change in distance between two anchorage points with a measurement sensitivity of ± 0.01 mm (± 0.0005?).
EDS - 80/1 Instrument housing
The Encardio-rite tape extensometer has an epoxy coated aluminum body for housing the digital display. The display is a 5 digit LCD which works on a 1.5 V silver oxide (SR 44) button cell with automatic power off facility.
EDS -80/2 Steel measuring tape
A precision steel measuring tape, punched with holes at a progressive distance of 20 mm (1?), provides the main scale reading on the model EDS-80 tape extensometer. To take the slack out of the tape measure, coarse tension adjustment is accomplished by engaging a pin of the extensometer in one of the spaced perforations on the steel tape.
Fine tension adjustment is achieved by rotating a knurled aluminum adjustment knob which reduces the overall length of the device, until two index marks provided on the extensometer, coincide. This results in a constant repeatable tension on the tape measure. The digital indicator measures this fine adjustment. This reading is added to the main scale reading to get the distance between the two anchors.
EDS - 80/3 Stainless steel shackle
For taking reading of any displacement which may have taken place, the stainless steel shackles are provided at both the ends of the steel tape. The shackles are easy to hook to the anchor bolts.
EDS - 80/4 Calibration frame
To check the zero stability and accuracy of the tape extensometer, Encardio-rite provides an optional calibration frame having an anchor distance of around 1 m. The calibration frame is of steel construction.
Recommended practice for maximum reliability and accuracy, it is recommended that one instrument be dedicated to each project. A calibration frame should be regularly used to check repeatability and determine a temperature correlation. The temperature should always be recorded and allowed to stabilize at the time of taking readings. In case the tape measure is changed, a new base reading must be established.
Accessories
The following accessories if separately ordered are available for use with the tape extensometer.
- Reference frame
- Replacement tape measure
- Groutable anchors
- Thermometer
- Flashlight
Download datasheet in pdf format, for detail specifications.
