Retractable Tape Rule Locking System Wedge Mechanism
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Solution Overview
Problem
Existing retractable tape rule assemblies lack a reliable locking mechanism that allows for secure extension and retraction of the tape rule blade, particularly at extended lengths, due to insufficient engagement between the stop assembly and the reel, leading to difficulty in maintaining the blade in the extended position against the spring's rotational bias.
Innovation Solution
A retractable tape rule assembly locking system comprising a stop assembly with a wedge and lever mechanism, a stop surface with hooks, and a compliant member, which engages the reel to prevent retraction and allows user-controlled locking of the stop assembly in the open position, ensuring the tape rule blade remains extended or retracted based on user input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stop assembly is engaged with the reel to prevent retraction, then the tape rule blade can be maintained in the extended position, but the stop assembly may unintentionally disengage or fail to maintain engagement, leading to loss of blade position
Solution Approach 1:
The stop assembly is designed to be movable between engaged and disengaged positions, allowing it to dynamically adapt to different operational states. The assembly can be intentionally moved by the user to disengage from the reel, providing controlled dynamics rather than fixed engagement
Solution Approach 2:
A compliant member acts as an intermediary element between the stop assembly and the reel. This compliant member provides a flexible connection that maintains reliable engagement while accommodating slight movements and misalignments, preventing unintentional disengagement without requiring complex locking mechanisms
2Ease of operation
If the stop assembly is made movable to allow user control, then ease of operation is improved, but the risk of unintentional disengagement increases
Solution Approach 1:
The stop assembly is designed with movable characteristics that enable user control. The assembly can be intentionally displaced by the user to disengage from the reel, providing ease of operation for extending and retracting the blade
Solution Approach 2:
The compliant member provides preliminary stabilization that prevents unintentional disengagement before it can occur. By accommodating slight movements and providing flexible engagement, it counteracts forces that might otherwise cause accidental release of the stop assembly
3Reliability
If the reel is prevented from rotating to retract the blade, then the blade remains extended for measurement, but the spring's rotational bias creates continuous force that may cause engagement failure
Solution Approach 1:
The stop assembly acts as an intermediary mechanical barrier between the reel and the blade. When engaged, it physically blocks the reel from rotating in the direction of the spring's bias, converting the continuous rotational force into a static engagement state that maintains blade position stability
Solution Approach 2:
The stop assembly provides dynamic engagement that can adapt to the spring's rotational bias. The movable design allows the assembly to maintain reliable engagement under varying force conditions while still permitting intentional disengagement when needed
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 system effectively maintains the tape rule blade in the extended or retracted position by engaging the stop assembly with the reel, preventing unwanted retraction and allowing controlled extension and retraction, enhancing user convenience and operational reliability.
Implementation Method 1
The biasing spring is configured to apply a rotational bias to the reel that rotates the reel to retract the elongated tape rule blade into the wound position
Implementation Method 2
The stop assembly is configured to selectively engage the elongated tape rule blade to maintain the elongated tape rule blade in the extended position or the wound position
Implementation Method 3
The wedge of the stop assembly is configured such that a first side of the wedge engages the wound portion of the elongated tape rule blade and a second side of the wedge engages the extended portion of the elongated tape rule blade
Data Source
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AI summary
The present disclosure relates to a retractable tape rule assembly locking system. The system comprises an elongated tape rule blade, a reel, a biasing spring, a stop assembly, a stop surface associated to the reel, a stop assembly locking device, and a housing assembly. The stop assembly is configured to engage the elongated tape rule blade to maintain the elongated tape rule blade in the extended position. Moreover, the stop assembly is provided with a pin to engage hooks of the stop surface to prevent rotation of the reel to retract the elongated tape rule blade. The stop assembly is configured to be moveable between a default position and an open position by a user. While in the default position, the stop assembly engages the elongated tape rule blade to prevent retraction of the elongated tape rule blade.