Telescopic Adjustable Leg with Dual Locking for Secure Retraction
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Solution Overview
Problem
Telescopically adjustable legs can become cumbersome or lose their inner parts when forces act to extend them during storage, leading to potential disengagement and loss.
Innovation Solution
A second locking member with a recessed engagement portion and a compression spring mechanism that allows one-handed operation, ensuring the inner leg is securely retracted, and a longitudinally oriented compression spring to prevent jamming and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single locking member is used to hold the inner leg part in position, then the device complexity is low, but the reliability is insufficient because forces during storage can overcome the locking resistance and cause the inner leg part to fall out or become cumbersome
Solution Approach 1:
The locking mechanism is divided into two separate locking members (first and second locking members) that independently engage with the inner leg part. Each locking member provides separate locking resistance, so that when both are engaged, they collectively prevent the inner leg part from extending during storage, thereby improving reliability without requiring a single complex locking mechanism
Solution Approach 2:
The second locking member is positioned within the housing that also contains the first locking member, creating a nested arrangement. The compression spring is also housed within the same housing structure. This nested design allows two locking mechanisms to coexist in a compact space, improving reliability through dual locking while minimizing the increase in overall device complexity
2Reliability
If a second locking member is added to securely hold the retracted inner leg part, then the reliability improves, but the device complexity increases
Solution Approach 1:
Both locking members are integrated into a single housing structure, and both are operated through a single actuator that moves sequentially. The compression spring provides unified resilient urging for the second locking member. This merging of components and operations reduces the practical complexity increase despite adding a second locking member, as the components share common structural and operational elements
Solution Approach 2:
The locking mechanism is designed to be dynamically controllable through a single actuator that can move the locking members between engaged and disengaged states. The compression spring provides dynamic resilient force that automatically urges the second locking member into engagement. This dynamic design allows reliable retraction security while maintaining operational simplicity through sequential movement controlled by one actuator
3Reliability
If the locking member is designed to provide strong locking resistance, then the reliability improves, but the ease of operation deteriorates because it requires two hands to operate
Solution Approach 1:
The compression spring is pre-loaded to provide resilient urging force that automatically pushes the second locking member into engagement with the inner leg part. This preliminary action ensures that strong locking resistance is achieved without requiring the user to manually apply force, allowing the strong locking to be engaged with a single hand operation of the actuator
Solution Approach 2:
The locking mechanism uses dynamic sequential movement where a single actuator first moves the first locking member, then through mutually engageable portions, automatically moves the second locking member into engagement. The compression spring provides dynamic resilient force throughout this sequence. This allows strong dual locking to be achieved through a single continuous hand motion, maintaining ease of operation while improving reliability
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
The design allows for secure retraction and extension of the adjustable leg with one hand, preventing loss and jamming, while maintaining stability and ease of use.
Implementation Method 1
The second locking member may be resiliently urged into engagement with the inner leg part. This may provide the advantage that movement of the first-mentioned locking member moves the second locking member out of engagement with the inner leg part, and movement of the first-mentioned locking member in the opposite direction moves the second locking member into engagement with the inner leg part. It may be thus resiliently urged by a compression spring.
Implementation Method 2
A longitudinally oriented compression spring may be arranged within the said outer leg part so that it engages the said inner leg part so as to urge the latter in a direction tending to increase the length of the telescopically adjustable leg. This reduces the likelihood of the leg jamming.
Data Source
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AI summary
An adjustable leg (10), or an article having such a leg (10), comprising inner and outer leg parts (12 and 16) the inner leg part (12) of which is slidable within the outer leg part (16) to enable the leg (10) to be telescopically adjustable in length. A locking member (70) is provided with an aperture (72) through which the inner leg part (12) passes, which locking member (70) is held directly or indirectly on the outer leg part (16) and is resiliently urged to adopt an angle with regard to the inner leg part (12). As a result edge portions defining the aperture (72) engage the inner leg part (12) and hold it in position relative to the outer leg part (16). A longitudinally oriented compression spring (50) is arranged within the said outer leg part (16) and engages the said inner leg part (12) so as to urge the latter in a direction tending to increase the length of the telescopically adjustable leg (10). The adjustable leg (10) is provided with a second locking member (82) which is moveable into and out of engagement with the said inner leg part (12). The first-mentioned locking member (70) and the second locking member (82) are provided with mutually engageable portions (88 and 90) by which movement of the first-mentioned locking member (70) out of engagement with the inner leg part (12) causes movement of the second locking member out (82) of engagement with the said inner leg part (12).