Although a light-duty conveyor belt is merely one component within a conveying system, its joint is arguably the most critical—and most failure-prone—part of the entire belt. In practice, over 70% of all conveyor belt failures occur at the joint.
Finger Joints
The finger joint is the most common joining method for light-duty conveyor belts and the strongest.
The conveyor belt undergoes a “fingering” process (cutting into interlocking teeth) followed by high-temperature vulcanization. This causes the interlocking teeth to mesh and fuse together seamlessly. The resulting joint maintains a thickness consistent with the rest of the belt and distributes tension evenly; the tensile strength at the joint typically reaches approximately 95% of the belt’s rated strength. The finger joint is also a globally recognized and widely adopted joining standard.
Overlap Joints
The overlap joining process begins with rough grinding using a grinding machine, followed by fine sanding. The belt ends are then layered and bonded together using a specialized adhesive. Finally, a dedicated joining machine applies heat to fuse and bond the layers, followed by a cooling phase. The thickness of the overlap joint remains consistent with that of the conveyor belt, and its tensile strength can reach up to 80% of the belt’s rated strength.
Steel Fastener Joints
Steel fastener joints are primarily intended for use in facilities with complex machinery or where belt removal is difficult. Different steel fastener models are selected based on the thickness of the conveyor belt. First, the fasteners are mechanically crimped onto both ends of the belt using a specialized tool. During installation, the user simply needs to interlock the two ends and secure them in place with a connecting pin (typically a steel wire). While steel fastener joints offer the convenience of easy disassembly, they are suitable only for light-duty conveyor belts; excessive tension can cause the fasteners to pull apart, thereby shortening the conveyor belt’s service life.
Causes of Joint Failure:
1. Excessive Load: This is the most common cause of conveyor belt joint failure.
2. Undersized Pulleys: Pulleys that are too small can place undue stress on the joint.
3. Excessive Tensioning: Overtightening the belt creates excessive stress; it is recommended to adjust the tension to an appropriate level.
4. Excessive Operating Speed: Operating the belt beyond its design limits can lead to failure.
5. Prolonged Operation: Continuous, long-term use leads to natural aging and material fatigue.
The strength and integrity of the joint serve as the foundation for ensuring the safe, reliable, and efficient operation of the entire conveying system. This critical factor permeates every stage of the process—from design and manufacturing to daily operation and maintenance—and stands as a key indicator of overall engineering quality and performance.
