Hinge Assembly Pivot Locking Mechanism
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Solution Overview
Problem
Existing hinge assemblies for mounting closure members like doors or gates are vulnerable to unauthorized removal due to the need for set screws and tapped screw threads, which are costly, difficult to remove, and prone to rust, especially when made of cheaper materials, and can be forced out with tools like hammers.
Innovation Solution
A hinge assembly design where the hinge pivot rotates within the pivot holes when a specific force is applied, allowing access only in the open position, using a lateral recess and transverse hole for tool insertion to lock the pivot against rotation, eliminating the need for set screws and tapped threads, and incorporating a spacer with a circumferential flange to prevent gripping by pliers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a set screw is used to lock the hinge pivot, then the hinge pivot cannot be removed, but the set screw is difficult to remove and may get stuck in the transverse hole
Solution Approach 1:
The hinge pivot is designed to rotate within the pivot holes when a moment of force is applied, changing from a static locked position to a dynamic rotating position. This rotation allows the lateral recess to align with the transverse hole, enabling tool insertion and locking against rotation only when needed for authorized disassembly.
Solution Approach 2:
A tool (pin or rod) is introduced as an intermediary element to lock the hinge pivot against rotation. The tool is inserted through the transverse hole into the lateral recess of the hinge pivot, providing the locking function without requiring a permanently installed set screw that would be difficult to remove.
2Reliability
If a screw thread is tapped in the transverse hole for the set screw, then the set screw can be installed, but additional costs and time are required and the thread may rust
Solution Approach 1:
The screw thread is extracted from the transverse hole design. Instead of tapping threads into the transverse hole to accommodate a set screw, the invention uses a smooth transverse hole that receives a tool for temporary locking. This eliminates the need for thread tapping operations and associated costs.
Solution Approach 2:
The tool (pin or rod) used to lock the hinge pivot is a simple, inexpensive element that can be easily manufactured and replaced if needed. It serves as a temporary locking mechanism during authorized disassembly rather than a permanent threaded fastener.
3Ease of operation
If the hinge pivot head is made accessible for gripping, then authorized disassembly is easier, but unauthorized removal with pliers becomes possible
Solution Approach 1:
The hinge pivot head is designed with an asymmetric shape that prevents gripping by pliers. The lateral outer edge has specific contours that do not provide a suitable gripping surface for standard pliers, while still allowing the application of rotational moment for authorized disassembly when the recess is aligned with the transverse hole.
Solution Approach 2:
The hinge pivot head combines a fixed asymmetric shape for preventing unauthorized gripping with a dynamic rotation capability. When a tool is inserted into the lateral recess, the pivot can rotate to enable authorized disassembly, but without the tool, the asymmetric shape prevents plier gripping.
4Reliability
If the hinge pivot is locked against rotation, then unauthorized removal is prevented, but authorized disassembly becomes more difficult
Solution Approach 1:
The hinge pivot transitions from a dynamic state (free to rotate) to a locked state (rotation prevented by tool insertion). The lateral recess aligns with the transverse hole only when the pivot rotates to a specific position, providing a simple mechanical indicator for when the tool should be inserted to lock against rotation and enable disassembly.
Solution Approach 2:
The hinge pivot's own rotation movement serves to align the lateral recess with the transverse hole, automatically indicating when the tool should be inserted. The system uses its own operational movement to facilitate the locking mechanism rather than requiring external alignment procedures.
Data Source
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AI summary
The hinge assembly comprises a first hinge member, having at least one loop forming a pivot hole; a second hinge member, having at least one further loop forming a further pivot hole, and a hinge pivot extending through said pivot holes to pivotally join the first and the second hinge members. The loop of the second hinge member is provided with a transverse hole giving access to the pivot hole and being accessible in the open but not in the closed position of said closure member. In order to avoid having to apply a set screw in this transverse hole to prevent the hinge pivot from being removed by unauthorised persons, the hinge pivot is rotatably mounted in the pivot holes. The hinge pivot is provided with a lateral recess which is accessible, in the open position of said closure member, by a tool inserted through said transverse hole in said further loop to lock the hinge pivot against rotation with respect to the further loop to enable screwing said fixing element on and off the hinge pivot.