How To Install J Hook Bolt
Installation method and accessories requirements
Required accessories
Washers: Spring washers (easy to collapse) are prohibited, and hardened flat washers (HV grade) are required to disperse pressure.
Nuts: Double nut locking (such as GB 1229 standard nuts), the lower nut is pre-tightened to 70% torque, and the upper nut is locked.
Installation process (taking railway concrete sleepers as an example)
| Step | Operation Key Points |
|---|---|
| 1. Pre-embedded Positioning | Bolt hook facing upwards, embedding depth ≥ 25 times the diameter (e.g., M24 bolt embedding depth 600mm) |
| 2. Concrete Pouring | Fix with a positioning frame during one-time pouring, deviation ≤ 2mm; backfill with non-shrink fine aggregate concrete for the reserved hole method |
| 3. Bolt Tightening | Tighten in two stages: initial tightening (60% pre-tightening force) → final tightening (100%), torque error ≤ ±5% (calibrated wrench required) |
| 4. Anti-loosening Inspection | Re-tighten after 24 hours of operation, and inspect every 6 months thereafter |
