Exit Device Assembly With Dual-Side Trim Locking Control
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Solution Overview
Problem
Existing exit device assemblies face security issues as the lock cylinder for the outside trim is accessible from the outside, requiring users to open the door to lock or unlock it, and existing solutions often require a new center case for the pushbar assembly, limiting functionality.
Innovation Solution
The exit device assembly features an interior lock cylinder on the interior side of the door and an exterior lock cylinder on the exterior side, allowing independent locking and unlocking from both sides, with the exterior lock cylinder providing a night latch function to maintain the unlocked state with a key inserted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lock cylinder is provided on the outside trim, then the exterior trim can be locked and unlocked, but a user located within the room needs to open the door to lock the outside trim
Solution Approach 1:
The locking function is segmented into two independent lock cylinders: one on the exterior trim and one on the interior pushbar assembly. This allows independent locking and unlocking operations from either side of the door, resolving the contradiction by enabling local control while maintaining security.
Solution Approach 2:
A cam mechanism acts as an intermediary between the two lock cylinders. The cam is selectively positionable in engagement with either the exterior lock cylinder or the interior lock cylinder, mediating the locking/unlocking action between the two sides and enabling secure operation from either location.
2Adaptability or versatility
If a key cylinder is provided on the center case of the pushbar assembly to block or unblock input from the outside trim, then locking and unlocking is possible, but it requires a new center case for the pushbar assembly
Solution Approach 1:
The locking/unlocking functionality is extracted from the center case and relocated to the pushbar assembly itself. The lock cylinder is mounted directly on the pushbar assembly, eliminating the need for modifications to the center case structure while maintaining full locking and unlocking capability.
3Ease of operation
If the lock cylinder is provided on the outside trim, then the exterior trim can be locked and unlocked, but locking and unlocking from the outside trim may not be possible when the input is blocked
Solution Approach 1:
The locking control is segmented into two independent locations: exterior lock cylinder on the outside trim and interior lock cylinder on the pushbar assembly. This segmentation ensures that blocking at one location does not affect operation at the other, maintaining versatility and availability of locking/unlocking functionality from either side.
Data Source
AI summary
An exit device assembly is provided in which the exterior trim can be locked and unlocked from an interior lock cylinder assembly on the interior side of the door and from an exterior lock cylinder assembly on an exterior side of the door. The interior lock cylinder assembly is located on a center case of the pushbar assembly, and the exterior lock cylinder assembly is located on the exterior trim. The interior lock cylinder assembly is operable to transition the exterior trim between a locked state and an unlocked state, and the exterior lock cylinder assembly is operable to lock and unlock the exterior trim.