Crane Hook Safety Latch

The crane hook safety latch is a vital safety protection device in crane hoisting equipment. It is mainly used to prevent the rigging or heavy objects on the hook from accidentally slipping off during operation, and to avoid casualties, equipment damage or production accidents caused by falling goods. The core of its design is to ensure that the hook opening is closed or restricted through a mechanical locking mechanism, thereby improving the safety of hoisting operations.

起重机钩安全闩锁

Crane hook safety latch structure

Crane hook safety latch usually consist of the following parts:

• Latch: A movable metal part that controls opening and closing through spring, gravity or manual operation.
• Pivot Pin: The core connection that supports the rotation of the lock tongue.
• Return Spring: Provides the elastic force for the lock tongue to automatically reset.
• Frame: integrated with the hook body to form a closed structure.

Working principle of crane hook safety latch:

• Anti-detachment design: When the hook is not stressed or hung normally, the lock tongue automatically closes under the action of spring force or gravity, covering the hook opening.
• Automatic/manual opening and closing: When hoisting, the lock tongue opens briefly under the pressure of the rope or spreader, allowing the rigging to enter the hook; once the load is stable, the lock tongue resets to prevent the rigging from sliding out.

What types of crane hook safety latch are there?

According to the operation mode and applicable scenarios, crane hook safety latch can be divided into the following types:

• Spring-type safety latch: relies on spring force to realize automatic closing, suitable for general-purpose cranes with frequent operations, and has high reliability.
• Gravity safety latch: It uses the dead weight of the lock tongue to close. It is common in large hooks. It has a simple structure but requires regular maintenance.
• Pin-type safety latch (manual latch): The lock tongue is fixed by manually inserting a pin, which is mostly used in special working conditions or overweight load scenarios.
• Rotary safety latch: The lock tongue can be rotated to the side of the hook to avoid interference with the spreader, and is suitable for narrow spaces.

起重机钩安全闩锁

Specifications for safe use of crane hook safety latch

Installation and inspection

Before installation, make sure that the lock and hook specifications match and there are no deformations or cracks. Check spring elasticity, latch integrity and lock tongue mobility before daily operation.

Operation precautions

• The sling needs to be fully embedded in the bottom of the hook to ensure the lock is fully closed.
• It is forbidden to force the lock to close to avoid damaging the mechanical structure.
• Avoid collision between the lock and obstacles during lifting.

Maintenance and replacement

Lubricate moving parts (such as springs, hinges) regularly to prevent corrosion and sticking. If excessive wear is found (such as spring failure, lock tongue deformation), it must be replaced immediately.

起重机钩安全闩锁

Relevant standards and regulations

International standards: ISO 4309 (Specifications for maintenance and scrapping of crane wire ropes), ISO 12480 (Requirements for the safe use of cranes).

Crane hook safety latch maintenance and upkeep

• Daily inspection: Before operation, manually test whether the lock tongue opens and closes smoothly to ensure that there is no jamming.
• Cleaning and lubrication: Regularly remove dirt from the lock tongue gap and apply high-temperature grease to the hinge shaft.
• Life management: Wear parts of safety locks (such as springs and lock bolts) need to be replaced according to the manufacturer’s recommended intervals, usually comprehensive maintenance every 2-3 years.

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Accident cases and lessons learned

案件: At a construction site, the lock spring failed to be replaced in time, causing the lifting steel plate to slip and cause damage to the equipment.

According to statistics, about 15% of crane accidents are directly related to hook decoupling. The standardized use of safety locks can significantly reduce such risks, while meeting the requirements of safety production regulations, extending the service life of equipment, and reducing economic losses caused by accidents.

Although the crane hook safety latch is a small component, it is the “last line of defense” for lifting safety. Scientific selection, standardized operation and system maintenance are the keys to exerting its functions. Today, when industrial safety is increasingly valued, choosing high-quality locks that meet standards and strengthening personnel training can significantly reduce the risk of accidents and ensure efficient operation of operations.

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