Hold Open Rod Axial Locking Mechanism
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Solution Overview
Problem
Existing hold open rods lack robust intermediate locking functionality, leading to poor performance and increased manufacturing costs due to stepped diameter constructions, which result in a sloppy fit and operational failures.
Innovation Solution
A hold open rod with a locking mechanism that includes a locking plug moving axially and a locking dog moving radially, operated by a lock transfer bar, allowing for intermediate locking positions between maximum and minimum lengths, preventing unlocking under load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a stepped diameter construction is used in the inner tube, then the locking mechanism can be simplified, but the manufacturing cost increases and operational reliability decreases
Solution Approach 1:
The patent changes the geometric parameters of the inner tube by using a constant diameter construction instead of stepped diameter, and modifies the locking mechanism parameters to use a camming action between a locking plug and locking dog. This parameter change resolves the contradiction by maintaining locking functionality while eliminating the need for stepped diameters, thereby improving reliability and reducing manufacturing costs.
Solution Approach 2:
The patent introduces dynamic elements to the locking mechanism, specifically a movable locking plug that interacts with a locking dog through camming action. This dynamic approach replaces the static stepped diameter construction, allowing the mechanism to achieve reliable locking without compromising operational performance.
2Adaptability or versatility
If stepped diameter constructions are used in the inner tube, then intermediate locking positions can be achieved, but manufacturing cost increases and fit precision deteriorates
Solution Approach 1:
The patent achieves intermediate locking positions by changing the parameter of the locking mechanism from stepped diameters to a continuous camming action system. The locking plug can be positioned at various points along its travel, providing multiple locking positions without requiring stepped diameter variations in the inner tube, thus maintaining manufacturing precision.
Solution Approach 2:
The patent segments the locking function from the tube construction itself. Instead of incorporating locking features directly into the tube diameter variations, the locking functionality is separated into a distinct mechanism with a locking plug and locking dog, allowing precise tube fabrication without compromise.
3Device complexity
If the hold open rod is configured for full extension or retraction only, then the structure is simplified, but adaptability decreases
Solution Approach 1:
The patent transforms the static full-extension-or-retraction configuration into a dynamic system where the locking plug can be positioned at multiple intermediate points. This dynamic capability allows the hold open rod to adapt to various door positions while maintaining relatively simple overall structure.
Solution Approach 2:
The locking mechanism is designed to perform multiple functions: it can lock at full extension, full retraction, and any intermediate position. This multi-functionality increases adaptability without proportionally increasing structural complexity, as the same camming mechanism provides all locking positions.
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 solution provides robust intermediate locking functionality, enabling the hold open rod to securely hold large loads without malfunctioning, reducing manufacturing costs and improving operational reliability.
Implementation Method 1
a locking dog configured to move radially between a locking position and an unlocking position as a result of a camming action with the locking plug as the locking plug moves axially
Data Source
AI summary
A hold open rod includes an inner member, an outer member configured to have the inner member slide in and out of the outer member, and a locking mechanism configured to selectively lock the inner member and the outer member with respect to each other. The locking mechanism includes a locking plug configured to move axially along an axis of the inner member and the outer member to a locking position and an unlocking position, a locking dog configured to move radially between a locking position and an unlocking position as a result of a camming action with the locking plug as the locking plug moves axially, and a lock transfer bar operatively connected to the locking plug and configured to move the locking plug to the locking position and the unlocking position when the lock transfer bar is moved.