Hammer - Springback instrument calibration method

Springback instrument meter is a measuring instrument for surface hardness of concrete mechanics, based on the relationship of concrete strength and surface hardness, strength of concrete is deduced, 1, pointer maximum static friction force of sliding block is very high, maintenance methods: adjust the springback needle slider spring coil and pointer shaft with firmness, the maximum static friction in accordance with ( 0. 40 - 0. 80). N, 2, spring working length less than 61. 2 mm nominal value, according to hooke's law, the spring is too short, the energy decreases, decrease of impact energy, the rebound hammer energy decreases, the springback value smaller, maintenance methods: adjust the spring seat spring fixed position, and make it within the prescribed scope, 3, the impact of the hammer and rod surface dust, impact in the process of friction increases, increases energy loss, the springback value is low, maintenance methods: remove dirt, 4, rebound hammer's position on the low side, launch position on the low side, leading to a low value, maintenance methods: screw in end cap screws, check the hammer hammer decoupling position, 5, 100 with center increases friction between the guide bar, energy loss is small, rebound value, low maintenance methods: lubrication center guide rod, the current method Yu Zaiyong reboiler of concrete used for calibration and how to calibrate the concrete rebound hammer technical requirements 1, test preparation, concrete resurfaced requirements: validation certificate trademark, export Numbers in accordance with the current national standard tag instrument type and name of the pointer should be located in the indicator dial '0', the name of the reboiler energy should be 2. 207 j, 2, are not allowed into obvious damage to the shell, and the collision and 3, the moving parts freely, reliable, and can not have loose, stuck, and affect the operation, indicating value of the pointer of the slider and the scale of marking should be clear agreement, 4, and exposed the ball should be smooth, no cracks, defects and corrosion, 5, anvil calibration, anvil weight 15. 1 kg, hardness HRC58 - 62, satisfy G89138 - 88 15 + 0. The requirements of 1 kg, and the factory certificate, concrete rebound hammer according to the technical specification for concrete compressive strength of the rebound method '(JGJ/T23 - 2011 to carry on the concrete strength test, calibration method, room temperature is 5-1 35 degrees Celsius, 2, steel anvil should be firmly placed in the concrete of the high rigidity, 3, when the boards down the impact on the rod should rotate in four directions, each time rotate 90 degrees to 4, bounce three times in each direction, the stability of the three readings jumping average, calibration results 1, average every turn rod calibration value should meet the requirements of 80 + 2, 2, do not conform to the requirements of the 80 + 2, should repair or send measurement inspection to repair verification, not accord with the requirement of 80 + 2 to unqualified 1, springback instrument calibration cycle, calibration cycle for 6 months, 2, concrete member rebound before the test, if test last a few days, the springback instrument should be calibrated once a day before the test, 3, when the rebound hammer value in engineering test rebound when in doubt, 4, and finished the work,