Part Numbers & Codes：7T3940, 9P2661, 9R2662
Application: Caterpillar bulldozer CAT D8T
Track Pitch: 215.9 mm
Width: To be confirmed
Related application reference:
7G6448 & 7T0737 for CAT dozer D7H, D7R, D8R, D8L
1S1924, 2M6880, 7S9093 for CAT dozer D8H, D8K
7T2750 & 9P2657 for CAT dozer D8N
Use of track boards
Most excavators use three stiffened track boards and a few use flat bottom track plates. In the design of three-bar caterpillar plate, the grounding pressure and the meshing soil capacity between the caterpillar bar and the ground should be calculated to ensure the necessary adhesion, and then the caterpillar plate should have higher bending strength and wear resistance. The three reinforced track boards usually have two clear holes. When the track plate rotates around the driving wheel, the sludge on the chain rail joint can be removed automatically by means of the gear teeth, so the sludge clearance hole should be located between the two screw holes that fix the track plate on the chain rail joint.
In order to protect the surface and reduce the turning resistance, it is more suitable to use the extended track and flat bottom track in the marsh or farmland. In order to ensure that the two adjacent crawler plates do not enclose rocks and cause excessive stress when the caterpillar chain is in any position (including grounding, rotating around the driving wheel and the guide wheel and the upper suspension position), the pitch of the caterpillar plate should be adjusted accurately, and the lapping lip with appropriate shape should be designed. The function of the lap lip is to form a tight strip between the track plates and form a strip at the beginning and the end. The track plate should be installed in the same direction. The smaller the pitch of track is, the smaller the crawler chain moves between the driving wheel and the steering wheel. The running uniformity is good, the wear of the track chain is low, and the driving efficiency is high when walking. But the minimum pitch value should be determined according to the machine weight and the number of track chains. The hole spacing between the two rows of chain rails with caterpillar plates should be generally larger so as to replace caterpillar plates with different grounding ratios. Walking devices used in marshes require very wide caterpillar panels and track surfaces, which sometimes have high bending stresses. For example, when the excavator works on the ground mixed with the residual roots, the main part of the excavator falls on a track board supported by the tree roots, so that the track board produces very high bending stress, thus affecting the life of the track board. In order to prevent damage and bending of track boards, section coefficient and bending strength must be improved. To increase the section coefficient, the height of the crawler bar must be increased, but this will obviously increase the turning resistance and affect the mobility of the excavator. Therefore, steel-rolled hollow crawler plates are suitable for walkers with widths exceeding 700 mm for use in marshes. Most of the two ends of the crawler board used in the marsh are made into slope angles, so as to protect the surface of the ground, reduce bending resistance and subsidence, and when walking on hard ground, the supporting arm is shortened and the bending moment of the edge bearing can be reduced.
The excavator with a track width exceeding 800 mm is mainly used for swamps, and is not suitable for general occasions. The excavator with widening and lengthening crawler travel device is especially suitable for pipeline engineering.