Gap-Free Door Lever Assembly for Psychiatric Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional door levers in psychiatric institutions allow ligatures to potentially become wedged in the pivot or shaft connection, posing a risk for suicide attempts by hanging, as the existing designs have gaps that can accommodate a ligature, enabling it to secure and support body weight.
Innovation Solution
A new door lever design featuring a mouse-like shape with an elongated smooth hump top surface and flat bottom, combined with a pivot plate and face plate assembly that eliminates gaps, ensuring any ligature will slide off and cannot be secured, with a pivot plate underlying the face plate to prevent wedging and a secure locking mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional door lever with pivot and shaft connection is used, then the lever can be easily manufactured and operated, but gaps in the pivot or shaft connection allow ligatures to become wedged and secured
Solution Approach 1:
The invention removes the traditional pivot shaft component entirely from the door lever assembly. Instead of having a pivot shaft that creates gaps, the lever is mounted directly to the door with set screws, eliminating the source of the ligature wedging problem while maintaining the essential pivoting function of the lever.
Solution Approach 2:
Rather than trying to make the pivot connection gap-free through complex design, the invention inverts the approach by eliminating the pivot shaft altogether and using a direct mounting method with set screws, thereby removing the gap creation mechanism at its source.
2Reliability
If the lever has a traditional elongated handle design, then it is easy to manufacture, but the shaft and handle surfaces provide engagement points for ligatures to secure
Solution Approach 1:
The lever handle is designed with a substantially spherical ball shape instead of a traditional elongated cylindrical form. This spherical geometry eliminates flat surfaces and sharp edges where ligatures could be wedged or secured, as any cord wrapped around the sphere will simply slide off due to the continuous curved surface.
Solution Approach 2:
The invention changes the geometric parameters of the lever handle from linear dimensions (cylinder) to radial dimensions (sphere), fundamentally altering the surface characteristics to prevent ligature engagement while maintaining manufacturability through standard spherical machining processes.
3Reliability
If the lever is mounted with traditional clearance between bottom of lever and door surface, then the lever has freedom of movement, but gaps allow ligatures to be wedged at the base
Solution Approach 1:
The mounting system is segmented into multiple independent components: the lever body, set screws for securing, and a washer for spacing. This segmentation allows the washer to provide the necessary clearance for pivoting motion while the set screws secure the lever to the door, preventing gap formation that would allow ligature wedging.
Solution Approach 2:
A washer is introduced as an intermediary component between the lever and the door surface. This washer provides the necessary clearance for the lever to pivot freely while preventing direct contact that would create gaps, thereby mediating between the conflicting requirements of motion freedom and gap elimination.
Data Source
AI summary
A lever and mounting plate combination attachable to the exposed vertical surface of a door that includes a latch assembly with a spindle extending horizontally outward from the vertical surface, the lever and mounting plate combination including a main plate mountable onto the door's exposed surface and having a window-like opening extending completely through the plate, a lever having a base part which is coupleable to the spindle and pivotable therewith and has an exposed outer part, and a lever plate fixed to the base part of the lever and pivotable with though lever and with the spindle when it is coupled to the lever, the lever plate closely underlies and contacts said inner surface of the main plate while at all times covering the window, the lever being engagable by a user to rotate the lever plate and simultaneously rotate the spindle to open the door.