JB/T 5317-2016 Chain Electric Hoist Standard Guide
JB/T 5317-2016 "Chain Electric Hoists" is the product standard for chain electric hoists. It specifies the type parameters, technical requirements, test methods, and inspection rules for chain electric hoists with a rated load of ≤5t.
Product Classification and Technical Parameters
Kelude offers a full range of chain electric hoists manufactured in strict compliance with national standards. Unlike wire rope hoists, chain electric hoists use alloy steel chain (Grade 80 or Grade 100) as the lifting medium. The chain offers a smaller bending radius, multi-directional flexibility, and lower dead weight. The standard defines seven rated load capacities: 0.125t, 0.25t, 0.5t, 1t, 2t, 3t, and 5t. The chain safety factor is ≥4 (relative to the chain's minimum breaking force). Grade 80 chain has a minimum tensile strength of 800 MPa, while Grade 100 chain is rated at 1000 MPa. Chain must be scrapped when wear exceeds 10% of the original diameter or when pitch elongation surpasses 5%. Regular lubrication of the chain is required during service.
The main difference between chain electric hoists and wire rope electric hoists lies in the hoisting mechanism — the chain hoist uses a chain sprocket to drive the chain, which can flex in any direction for superior handling. The standard requires chain hoists to be equipped with an overload protection device (either a ratchet friction clutch or electronic overload protection) that slips or triggers an audible alarm and shuts down when the load exceeds 110% of the rated capacity. Friction-clutch overload protection is preset at the factory and must not be field-adjusted during service.
The standard sets detailed requirements for the load chain — it must be Grade 80 or Grade 100 high-strength chain as specified in GB/T 24814. The chain sprocket tooth profile must match the chain pitch to ensure smooth engagement without skipping. The chain container must be properly sealed to prevent dust ingress. The maximum lifting height of a chain electric hoist is generally limited to 12 m (up to 30 m with special design) due to the self-weight of the chain. The standard also specifies a test load of 1.5 times the rated load for chain hoists (higher than the 1.25 times required for wire rope hoists), reflecting the higher risk of brittle chain fracture compared with the progressive failure mode of wire rope.
The brake system on chain electric hoists incorporates a ratchet friction clutch as the overload protection device — when the load exceeds 110% of the set value, the friction clutch slips to prevent chain overloading and fracture. The clutch slip torque is precisely adjusted at the factory using a dedicated torque wrench and must not be altered in the field. The adjusting nut must be secured with a tamper-proof seal. The standard also mandates both upper and lower limit switches to prevent the hook from striking the hoist body or the chain from paying out excessively.
Brake System and Safety Requirements
Brake requirements under the standard — braking torque must be ≥1.5 times the rated load torque, and the brake must reliably hold 1.25 times the rated load. Brake slip distance under rated load must not exceed 100 mm. On disc brakes, the brake ring must be replaced when wear exceeds 50% of the original thickness. Asbestos-free, environmentally friendly friction materials are mandatory. Brake ring wear must be inspected weekly.
The standard requires chain electric hoists to be fitted with a hook latch to prevent the sling from detaching from the hook throat. Hooks must come with a Product Certificate and an inspection report. A hook must be scrapped when wear on the critical cross-section exceeds 10% of the original dimension or when throat opening increases by more than 15%. Control voltage is safety extra-low voltage at 36 V or 48 V. The control box must have a Protection Rating of at least IP54. Power supply is via C-type or H-type conductor rail.
Seven Models
Tensile ≥800 MPa
Hook ≥4
Holds 1.25× Load
Factory Set
IP54 Rating
| Lifting Capacity(kg) | chaindiameter(mm) | speed(m/min) | Power(k W) | Dead Weight (kg) |
|---|---|---|---|---|
| 125 | 6.3 | 8 | 0.8 | 42 |
| 250 | 7.1 | 8 | 1.5 | 50 |
| 500 | 8.0 | 8 | 2.2 | 65 |
| 1000 | 10.0 | 8 | 3.0 | 85 |
| 2000 | 11.2 | 8 | 5.0 | 120 |
Inspection & Test Requirements
Routine tests include a no-load test (full travel, 5 cycles minimum), a rated load test (3 lift/lower cycles with load drop measured at ≤100 mm), a 1.25× static load test (held for 10 minutes), and an insulation test (≥1 MΩ). Type tests are conducted every 2 years and cover all routine test items plus a damp-heat test, vibration test, and chain durability test. In service, inspect chain wear and lubrication every 500 operating hours, and replace the reducer oil every 1,000 operating hours.
| inspection items | technical requirements | cycle | assessment |
|---|---|---|---|
| No-Load Test | full travel≥5times | factory | smooth, free of Abnormal noise |
| rated load | lifting and lowering3times | factory | drifting≤100mm |
| Static load test | 1.25times×10min | annual | smooth, free ofpermanent deformation |
| chaininspection | Wear≤10% | 500h | ≤original diameter10% |
| insulation test | ≥1MΩ | semi-annual | conforming |
Standard requirements for chain lubrication on chain electric hoists — the load chain must be kept adequately lubricated during operation, and a dedicated chain lubricant is recommended. When the chain sprocket shows significant wear, it should be replaced together with the chain — fitting a new chain to a worn sprocket will accelerate chain wear. Connecting links must be of the same grade as the load chain; standard steel rings are not acceptable substitutes. The chain container on a chain hoist should be sealed and dustproof.
FAQ
Q: What is the difference between a chain electric hoist and a wire rope electric hoist?
A: A chain electric hoist uses an alloy steel load chain (Grade 80 or Grade 100) instead of wire rope. The chain has a smaller bending radius, can flex in multiple directions, and is lighter in dead weight, making it suitable for lower lifting capacities (≤5t) and applications with restricted lifting height. A wire rope hoist offers greater lifting height, smoother operation, and higher safety, making it suitable for general hoisting applications.
Q: What is the safety factor of the load chain on a chain electric hoist?
A: The standard requires a chain safety factor of ≥4 (relative to the chain's minimum breaking force). Grade 80 chain has a tensile strength of ≥800MPa, and Grade 100 chain ≥1000MPa. The chain should be scrapped when wear exceeds 10% of the original diameter or when pitch elongation exceeds 5%. The chain must be kept lubricated during use, and a heavily worn sprocket should be replaced together with the chain.
Q: What are the braking features of a chain electric hoist?
A: Chain electric hoists typically use a disc brake with a braking torque of ≥1.5 times the rated load torque. Brake slip distance under rated load must not exceed 100mm. The brake ring should be replaced when wear exceeds 50% of its original thickness. Check brake ring wear weekly.
Q: How does overload protection work on a chain electric hoist?
A: An overload protection device (ratchet friction clutch or electronic overload protection) must be fitted. At loads exceeding 110%, the clutch slips or an alarm stops the lifting motion. Friction-clutch-type devices are adjusted before delivery and must not be tampered with during use. Overload protection should be verified monthly to ensure accurate trip points.
