Fall-prevention device lever stop mechanism
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Solution Overview
Problem
Existing fall-prevention devices for workers at height are not sufficiently safe and reliable, as users can inadvertently release the device from the securing support, posing a high risk of accidents, especially for inexperienced users.
Innovation Solution
A movable fall-prevention device with a lever that rotates between open and closed positions, featuring a locking cam and a stop that is locked in place by an abutment surface tilted at an angle between 90° and 135°, preventing unintended release, and a secondary abutment surface to enhance locking security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stop is provided to limit lever rotation in an intermediate position, then the device prevents the securing support from coming out, but the user can still inadvertently release the device by forcing the stop rotation
Solution Approach 1:
The invention divides the lever into two functional segments: a first portion that contacts the stop and a second portion that engages the securing support. This segmentation allows the stop to limit rotation of the first portion while the second portion maintains engagement with the securing support, preventing inadvertent release.
Solution Approach 2:
The invention introduces an intermediary element (the stop) between the lever and the securing support. The stop acts as a mediator that limits the rotation of the lever in the intermediate position, preventing the lever from disengaging from the securing support while still allowing controlled operation.
2Ease of operation
If the lever contacts the stop at a tilted surface, then the lever can rotate freely, but the stop cannot effectively prevent rotation
Solution Approach 1:
The invention employs asymmetric geometry where the lever has a first portion with a specific contact surface angle (between 30° and 60°) relative to the stop. This asymmetric design ensures that when the lever contacts the stop, the contact surface is optimized to prevent rotation while allowing controlled movement, resolving the contradiction between rotation freedom and stop effectiveness.
Data Source
Figure 1
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AI summary
A movable fall-prevention device (1) for a securing support (6) is described, comprising a main body (1×a) having a passage (40) for the insertion/removal of the securing support in/from a restraining groove (9), wherein the securing support (6) is restrained through a lever (16) rotating between an open position and a closed position, and wherein one of the lever ends comprises a locking cam (10, 25) and the other free end comprises a hole (23) intended to receive a karabiner (5). The device further comprises a stop (50) movable between an operative position, in which it limits the rotation of the lever (16) in an intermediate position when the lever is moved from the closed position to the open position, and a release position in which it allows the rotation of the lever (16) in the open position. The lever (16) comprises at least one abutment surface (80a) cooperating, in the intermediate position, with at least one corresponding engaging surface (53 a) of the stop (50) to lock the stop (50) to the operative position. The abutment surface (80a) is tilted by an angle (α) substantially comprised between 90° and 135° with respect to the movement path (T) of the stop (50) from the operative position towards the release position.