Adjustable Backset Cylindrical Latch Mechanism
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Solution Overview
Problem
Standard backset distances for door latch mechanisms are inflexible, failing to accommodate doors with varying backset distances, which can lead to improper fitting and functionality issues.
Innovation Solution
An adjustable backset cylindrical latch mechanism that includes a tailpiece with two axially spaced transverse recesses and a rotatable second tailpiece member, allowing for axial movement between different backset positions, ensuring compatibility with multiple backset distances by preventing relative axial movement in specific rotational positions and allowing it in others for positional transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard backset latch mechanism is used, then the latch fits standard door backsets (2 3/8 inches or 2 3/4 inches), but it cannot accommodate doors with different backset distances
Solution Approach 1:
The latch mechanism incorporates a dynamic adjustable feature where the tailpiece can be repositioned between two fixed positions (2 3/8 inches and 2 3/4 inches). The adjustable tailpiece includes a bore with transverse recesses that engage with protrusions on the operator, allowing the tailpiece to be set at different axial positions relative to the latch bolt. This dynamic adjustability enables the same latch mechanism to accommodate different backset distances while maintaining structural integrity and proper functionality.
2Adaptability or versatility
If the tailpiece is made adjustable to accommodate different backset distances, then versatility improves, but the risk of improper assembly and malfunction increases
Solution Approach 1:
The adjustable tailpiece incorporates localized engagement features consisting of transverse recesses in the tailpiece bore and corresponding protrusions on the operator. These localized features engage at specific axial positions to provide positive mechanical locking. The recesses and protrusions are positioned to ensure proper alignment and prevent improper assembly, as the protrusions can only engage the recesses at the predetermined backset positions (2 3/8 inches or 2 3/4 inches), ensuring reliable functionality.
3Ease of operation
If the second tailpiece member is made rotatable to allow adjustment, then ease of installation improves, but the risk of unintended movement during operation increases
Solution Approach 1:
The second tailpiece member is designed with rotational capability to facilitate adjustment during installation. The tailpiece can be rotated to align the transverse recesses with the protrusions on the operator, allowing the installer to select the desired backset position (2 3/8 inches or 2 3/4 inches). Once positioned, the protrusions engage the recesses to provide positive mechanical locking that prevents unintended axial movement during normal operation. The rotational adjustment is intended for installation only, and the engagement features ensure the tailpiece remains fixed in the selected position.
Data Source
AI summary
A latch assembly comprises a latch bolt and a tailpiece including a first tailpiece member mounted to the latch bolt and a second tailpiece member. The second tailpiece member is movably received in a bore of the first tailpiece member and operably connected to a latch operator. The second tailpiece member is received in one of two axially spaced recesses in the bore in a first backset position and a second backset position. Relative axial movement between the first tailpiece member and the second tailpiece member is prevented in a first relative rotational position in the first backset position and in a second relative rotational position in the second backset position, and relative axial movement is allowed in a third relative rotational position to allow the second tailpiece member to be moved between the first backset position and the second backset position. A housing slidably receives the latch bolt therein and a casing defining a peripheral slot having two axially spaced circumferential portions interconnected by a longitudinal portion receives the housing such that a protrusion on the housing is slidably received in the slot. Relative axial movement between the casing and the housing is prevented when the protrusion is in either one of the two circumferential portions of the slot in a first rotational position in the first backset position and in a second rotational position in the second backset position, and relative axial movement is allowed in a third rotational position to allow the protrusion on the housing to be movable along the longitudinal passage between the circumferential portions of the slot when transitioning between the first backset position and the second backset position.