Pendulum friction coefficient tester is an instrument for measuring friction coefficients of road surface, airport runway, marking paint and so on. It can also be used as a basis for determining various tire formulas through the measurement of typical road friction coefficients. The instrument is highly convenient and simple to operate. It has a relatively small impact on traffic during the test, and the data is more stable. And can be used indoors and outdoors.
Pendulum friction coefficient measuring instrument Pendulum instrument is a dynamic pendulum impact type instrument. It is developed based on the basic principle of "the loss of positional energy of the pendulum is equal to the work done by the rubber piece installed at the end of the swing arm sliding over the road to overcome friction such as road surface".
Technical specifications of pendulum friction coefficient tester:
★ Swinging moment: 615.000 grams mm
★ Weight of pendulum: 1500 ± 30g
★ Swinging moment: 410 ± 5 mm
★ The static pressure of the rubber sheet on the road surface: 2263 grams.
★ The number of times the pendulum has been freely lowered from 50 places to the stop of the swing is not less than 70 times.
★ The distance between the outer edge of the rubber sheet and the swing is 508 mm.
★ The total weight of the instrument is about 14 kg.
How to use the pendulum friction coefficient tester:
★ Selection point: On the test section, along the left wheel track in the driving direction, select five representative measurement points, and each measurement point is about 5-10 meters apart.
★ Instrument leveling: (1) Place the instrument on the measuring point (see the appendix for the calibration method), and make the swing direction of the pendulum consistent with the driving direction. (2) Move the pendulum to the right and press the release switch. Put the snap ring into the release switch slot, the threshold is in the horizontal release position, and then release the release switch. At this time, the pointer should be pulled close to the pin. (3) Press the release switch to move to the left, and the pointer should point to zero. If it is not zero, you can slightly tighten or loosen the felt ring adjustment nut. Repeat this operation until the pointer points to zero.
★ Calibration slide length:
(1) Use a rubber brush to remove loose particles and debris on the pavement inside the swing van.
(2) Let the pendulum hang from the mountain, set a standard ruler (126 mm) in the direction of the parallel external swing of the rubber sheet, loosen the solid handle, and turn the lifting handle. Slowly lower the pendulum. When the rubber piece on the skid block has just touched the road, lift the lifting handle to raise the skid block, move the pendulum to the right, and move the lifting handle to lower the pendulum for a distance, then lower the lifting lever to make the pendulum Slowly move to the left until the edge of the rubber sheet just touches the road, aligning the end of the 126 mm ruler. Then use the hand to lift the lifting handle, so that the slippery block is lifted up, and the pendulum continues to move to the left. Lower the lifting handle, and then slowly move the pendulum to the right to make the rubber of the rubber piece touch the road again. After the distance between the contact point of the rubber sheet and the road surface is 126 mm, tighten the handle tightly and correct it again. If the sliding length does not meet the standard, raise or lower the leveling screw on the front of the instrument base to correct it, but The level must be leveled. Make the sliding length meet the requirements. After that, place it in the horizontal release position.
★ Determination: Water the pavement with water, and scrape it with a rubber brush to wash away the mortar, then sprinkle the water, and press the release switch to make it slide on the road. The pointer can indicate the value of the road surface friction coefficient (a section A May not be recorded). When the pendulum swings back, catch the pendulum lever with your left hand, lift it with your right hand to raise the slippery block, and move the pendulum to the right to press the switch to enter the pendulum snap ring into the release switch, and turn the pendulum needle to Dial the needle, repeat this item, measure five times (each time should be sprinkled with water), and record the value of each time. The difference between the five times is not more than three units (one and a half of the scale). If the difference is more than three units, the cause should be checked, and the above operations should be repeated again until the requirements are met.
★ Measurement results: (1) The average value of the five measurement counts at each measuring point represents the friction coefficient value of the measuring point, and the average value of the friction coefficient of the five measuring points is used. Represents the value of the coefficient of friction of the measured section. (2) Determine the reading. The reading of the pointer on the dial (referred to as "swing value"), divided by 100, is the friction coefficient of the road surface. For example: the swing value is 33, and the friction coefficient is 0.33.
Structure of pendulum friction coefficient tester
★ Base: It consists of T-shaped legs, leveling screws and level bubble. Level and support the instrument.
★ Column: composed of the same column, lifting mechanism, guide rod and instrument handle. For lifting and fixing the position of the swing head.
★ Release switch: a switch mounted on a cantilever. It is used to maintain the horizontal position of the swing bar and release the function of swinging down.
Swing head: It consists of a fastening handle, a swing shaft, a steering knuckle, and a bearing. It plays a role of connecting the pendulum and fixed position to ensure free swing in the swing plane.
★ The indicator system is composed of pointer, felt ring, flange, fastening nut and dial. The pointer can directly indicate the value of friction coefficient.
★ Swing: It consists of upper and upper joints, swing lever, spring, lever system, lifting handle, shell, slippery block and rubber sheet. It has a prescribed torque in the swing and a prescribed pressure on the road surface. The front and back, left and right moments are balanced. It is a measure of the friction coefficient of the road surface.