Lifting Hook Safety Pawl Operating Extension
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Solution Overview
Problem
Existing moving hooks for concrete formwork elements require operators to climb ladders to pivot the safety pawl from the locked to the release position, making handling difficult and unsafe, especially when dealing with high formwork elements.
Innovation Solution
The moving hook design includes an operating extension on the safety pawl that allows operation from below using an operating rod, enabling the safety pawl to be pivoted from the locked to the release position without needing to climb a ladder, along with a spring mechanism to secure the pawl in the locked position and a chain deflector to prevent accidental engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the safety pawl is held in the locked position by gravity, then the structure is simple, but the safety pawl can easily fall out of the locked position when the lifting hook is not sufficiently tensioned
Solution Approach 1:
The patent introduces a dynamic spring mechanism that adapts to the tension state of the lifting hook. When the hook is not sufficiently tensioned, the spring allows the safety pawl to remain in the locked position. When properly tensioned, the spring force increases to ensure the safety pawl stays locked, providing adaptive stability based on operational conditions.
Solution Approach 2:
The spring mechanism changes the force parameters acting on the safety pawl based on the tension state of the lifting hook. As the hook transitions from untensioned to tensioned state, the spring force parameter increases, thereby increasing the stability of the safety pawl in the locked position.
2Device complexity
If the operator must reach up to the setting hook with both hands to pivot the safety pawl, then the operating mechanism is simple, but the operator has to climb a ladder which reduces safety and increases difficulty
Solution Approach 1:
The patent extends the operating extension of the safety pawl horizontally outward from the hook structure, creating a new operational dimension. This allows the operator to access and operate the safety pawl from below or from a safer position, eliminating the need to climb a ladder while maintaining mechanical simplicity.
Solution Approach 2:
The extended operating extension acts as an intermediary element between the operator and the safety pawl mechanism. It transmits the operator's force from a safe distance, allowing operation without direct manual manipulation of the safety pawl itself and without requiring the operator to climb.
3Reliability
If the safety pawl always remains in the locked position, then security is improved, but the operator cannot release the hook without climbing a ladder
Solution Approach 1:
By extending the operating extension horizontally outward from the hook structure, the patent enables the operator to access the release mechanism from below or from a safer position. This dimensional change maintains the security of the locked position while providing accessible release capability without requiring the operator to climb a ladder.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances user-friendliness and safety by allowing operators to manage the hook from a safer position, speeding up work processes and securely holding frame profiles of varying thicknesses.
Implementation Method 1
a spring mechanism to secure the pawl in the locked position
Implementation Method 2
a chain deflector to prevent accidental engagement
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
The invention relates to a lifting hook (1) for lifting concrete formwork elements using a hook (7), which comprises an opening (8) for receiving a frame profile (9) of the concrete formwork element, and a safety pawl (2) which is pivotably mounted on the hook (7) by way of a pintle (5) and has at least one blocking region (20), wherein in the blocking position the safety pawl (2) blocks the opening (8) such that a frame profile (9) is prevented from being received in the opening (8) and in the locking position a frame profile (9) received in the opening (8) is secured by the blocking region (20) resting against the frame profile (9), and wherein in an area of the safety pawl (2) removed from the blocking region (20) fastening means (30) for fastening a chain (19) are provided such that the safety pawl (2) is forced into the blocking position and/or the locking position when a tractive force is applied to the fastening means (30) by way of the chain (19). At an end region of the safety pawl (2) facing away from the fastening means (30), an operating extension (35) is provided for pivoting the safety pawl (2) using an operating rod (3).