Purpose

This product is mainly used for testing the friction coefficient of high-grade highways, laboratories, and airport runways. It can also be used to test the anti-slip performance of surfaces such as rubber tracks and floor tiles to evaluate the road surface's anti-slip performance (before evaluating the anti-slip value, it is necessary to replace the rubber sheet with a hardness of 96 or adjust the normal static pressure of the rubber sheet on the ground from 22.2N to 24.5N, which is also feasible). It is also used to measure the polishing value of specimens after accelerated polishing machine tests for stone materials. The pendulum tester is an essential testing instrument for the accelerated polishing machine for stone materials.

Structure and Main Parameters

1. The instrument mainly consists of the following main components: T-shaped cast iron base, lifting assembly, release switch assembly, power pendulum assembly, specially designed fan-shaped scale dial, and pendulum needle rotation assembly.

2. Main parameters:

① Pendulum weight: 1500±30 grams;

② Pendulum center of gravity distance: 410±5 mm;

③ Slider: When testing the friction coefficient of the road surface (wet anti-slip value), it is 32±5g (random). [When testing the polishing value (or dry anti-slip value), it is 20±5g optional].

Rubber sheet: Hardness 55±5HA, size 76.2x25.4x6.35±0.5 mm [random] for wet anti-slip value; [31.75x25.4x6.35±0.5 mm (or dry anti-slip value) optional].

④ Normal static pressure of the rubber sheet on the road surface: 22.2N±0.5N (2263g±50g);

⑤ Distance from the lower edge of the rubber sheet to the pendulum center: 510±2 mm;

⑥ Scale length: dual-purpose scale (126±1 mm, 76±1 mm);

⑦ Pointer weight not exceeding 85g, nominal length 300±1 mm.

Usage Method

1. First, unpack the instrument and install it. Secure the rear support foot of the base with screws (first loosen the left screw at the back of the base, then straighten the T-shaped leg, and screw the previously loosened screw into the small hole of the T-shaped leg to fix it tightly). Remove the fixing clamp between the main column and the pendulum rod.

2. Level the instrument: Turn the leveling bolt on the base to center the bubble. Ensure the rubber sheet does not touch the ground.

3. Pointer zero adjustment:

① Lift the pendulum to the right and lock it into the release switch (pendulum rod in horizontal position). Use your finger to push the upper part (short end) of the pointer counterclockwise downward to the position just touching the adjustment screw. (Many people mistakenly push the long end of the pointer with their finger, which is a serious error.)

② Press the release button to let the pendulum rod fall to the right horizontal position. When the pendulum rod moves left to the high position and falls back, before the rubber sheet contacts the object surface, catch it by hand (pendulum suspended state). At this time, the pointer should indicate zero on the scale. If not at zero, fine-tune the white nut at the pointer rotation center (if the pointer is above zero, turn the nut clockwise; if below zero, turn it counterclockwise. Alternatively, adjust the small screw on the pointer dial). Repeat the above steps until the pointer indicates zero.

4. Verify sliding length: On the above basis, clean the ground.

① Let the pendulum be in a free suspended state, with the lowest corner of the rubber sheet just touching the object surface. Align the centerline of the scale with the lowest corner of the rubber sheet (about 5mm distance between scale and rubber sheet). First, loosen the black star handle at the back (half to one turn), then turn the black star lifting handle on top (turn counterclockwise to lower) to lower the pendulum. Meanwhile, move the pendulum to either side. After lowering to a suitable height (about one turn), gently place the pendulum so the rubber sheet just touches the test ground. Mark the contact position of the rubber sheet on the ground. Then lift the hook on the pendulum to move it to the other side, release the hook so the lower edge of the rubber sheet lightly touches the ground, and mark again. The distance between the two marks should be 126mm. If the distance between the two marks does not match the scale, turn the top nut to adjust the mark distance (one full turn of the handwheel equals 6mm) until it matches the 126mm scale. You can also adjust the three leveling screws on the base to meet the requirement (ensure the bubble is centered), then lock the black star handwheel on top and level the instrument again.

② Repeat the above operation until the sliding length is 126mm. Lock the rear star handwheel. (The sliding length of 126mm for the lowest corner of the rubber sheet on the object surface must be accurate, as this length determines the accuracy of the pendulum value).

If unfamiliar with the operation, you can request an operation video from the seller!!!!!!

5. After completing the above work, you can test the road surface. First, move the pendulum rod to the right cantilever to place the pendulum rod in the horizontal release position. Turn the short end of the pointer counterclockwise to the left side near the fine adjustment screw, just touching it. Spray water on the test point on the road surface with a spray bottle, and use a scraper or brush to remove excess water from the road surface.

6. Ensure the pendulum direction is consistent with the driving direction. Sprinkle water on the test point, press the release switch to let the pendulum slide on the road surface. When the pendulum rod falls back, catch it by hand. The value indicated by the pointer is the pendulum value of the road surface. Do not record the first measurement. Then reset the pendulum rod and pointer to the horizontal release position.

7. Repeat the above operation. The selected test points should be more than 5m and less than 10m apart. Measure each point 6 times; do not record the first value, record the last five values and take the average as the pendulum value for that point. Divide the pendulum value by 100 to get the friction coefficient. The difference between the maximum and minimum of the five values should not exceed 3. If the difference is greater than 3, check the cause and repeat the operation.

8. According to the road surface temperature, correct the measured values according to the calculation method in chapter T0964-2008 of the specification (when measuring friction coefficient or anti-slip value, only read the value on the right side 0--150 of the fan-shaped scale dial).

9. When testing the polishing value of stone samples (read the polishing value from the left scale of the sector dial, 0-100 is the polishing value, 0-150 is a useless value), the sliding length is 76mm. Other operations are the same as above. The polishing value can be directly read on the scale plate (the reading on the left side of the sector dial divided by 100 is the polishing value; reading the decimal directly is also acceptable).

10. After each test, the instrument must be wiped clean. Apply a small amount of oil to lubricate and prevent rust on the sliding parts of the column and the three leveling screws on the base. Secure the pendulum and column with clips and store properly.

*Troubleshooting: After receiving the goods or using for a period of time, if a large axial clearance is found in the steering knuckle, you can remove the decorative cover in front of the steering knuckle. There is a cross recessed countersunk screw at the shaft end; tighten it lightly with a screwdriver (apply slight force only, excessive force will affect bearing flexibility)!! There is a small screw below the pendulum that can adjust the swing center distance to 510mm.

This instrument needs to be recalibrated at the factory once a year. Non-professionals should not operate it to avoid damage!!

Packing List

1. Main Unit: One 2. Manual: One copy (including certificate of conformity)

3. Scale: One 4. Spray Bottle: One 5. Scraper: One

BM-III Type Pendulum Instrument (Operating Instructions)

(Screw Rod Lifting Structure)

1. First, unpack the instrument and install the base so that the level bubble is centered. Remove the clips on the pendulum and column; the pendulum will naturally hang down. Ensure the rubber sheet below the pendulum does not touch the ground.

2. Use your hand to lift the pendulum to the right and lock it into the slot of the switch body at the upper right. Gently press the upper end of the pointer downward to the screw (light pressure required), then press the release button. The pendulum will fall and move left to the stop position. You must catch it with your left hand. Let it down and check if the pointer points to zero. If it is above zero, slightly turn the white plastic nut in the middle of the pointer clockwise. If below zero, turn the nut counterclockwise. Repeat this gently several times until the pointer is at zero. When the error is very small, adjusting the small screw on the pointer's dial can also meet the requirement.

3. After pressing the release button each time, when the pendulum moves left to the stop position and falls, you must catch it by hand to prevent damaging the pointer. Read the value, then use both hands to lock the pendulum into the slot.

4. Adjust to 126mm: First, move the pendulum to the right and lock it into the slot. Then loosen the black star-shaped handwheel at the upper back (half to one turn is enough). Turn the black handwheel on top counterclockwise to lower the pendulum. Gently place the pendulum down so that the rubber sheet at the bottom just touches the ground. Place the scale in front of the rubber sheet so that the center line of the scale aligns with the angle line where the bottom of the rubber sheet just touches the ground (about a few millimeters away from the rubber sheet). Use your finger to lift the right hook of the pendulum, move the pendulum aside, turn the black star-shaped handwheel on top counterclockwise about half a turn and pause. Then lift the right upper hook of the pendulum and move it left and right to see if the lower corner of the rubber sheet aligns with the 126 mark on the scale. If it is beyond the 126 mark, slightly turn the top handwheel clockwise until the lower corner of the rubber sheet corresponds to the 126 mark on both ends of the scale. Then tighten the black star-shaped handwheel at the upper back.

5. After tightening the black handwheel at the upper back, the rubber sheet friction length of 126mm may be slightly small. If there is a deviation, you can slightly adjust the two black leveling screws at the front of the instrument base.