Long-bar latch with enhanced serviceability features
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Solution Overview
Problem
Existing long-bar latches in ovens require extensive disassembly for servicing due to reliance on self-tapping screws, which can strip and compromise positioning, and have limited latch hook pull-in force, leading to potential improper self-clean process operation.
Innovation Solution
A long-bar latch with a serviceable motor and plate subassembly that uses a self-tapping screw to secure to a rear bracket, featuring tabs and rectangular apertures for precise positioning and a non-tapped aperture for secure fastening, along with a single-point electrical connector for accurate wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If self-tapping screws are used to secure the motor and plate assembly, then the assembly can be fastened to the rear bracket, but the screws are vulnerable to stripping due to worn apertures and over-torquing
Solution Approach 1:
The patent divides the fastening system into two distinct components: tapped apertures in the rear bracket that provide threaded engagement, and separate self-tapping screws that secure the motor and plate assembly. This segmentation allows the bracket to provide reliable threaded engagement while the screws provide removable fastening, reducing the risk of stripping affecting the entire fastening system.
Solution Approach 2:
The rear bracket is pre-formed with tapped apertures during manufacturing, creating ready-made threaded engagement points before the self-tapping screws are installed. This preliminary action ensures that the threaded engagement structure is already in place and properly formed, eliminating the need for the screws to create their own threads in the bracket and reducing the risk of stripping.
2Ease of operation
If screws are used to position the motor and plate assembly, then the assembly can be secured to the rear bracket, but accurate positioning is difficult to achieve and verify
Solution Approach 1:
The tabs on the motor and plate assembly are designed to self-align with and insert into the tapped apertures of the rear bracket during installation. This self-service mechanism automatically ensures proper positioning and alignment without requiring the technician to perform complex alignment procedures or verification steps, making the assembly process both easy and precise.
Solution Approach 2:
The tabs act as intermediary elements between the motor and plate assembly and the rear bracket. These tabs provide dedicated alignment features that guide the assembly into the correct position as it is being secured, ensuring accurate positioning without requiring the technician to measure or verify alignment separately.
3Reliability
If the latch hook pull-in force is increased, then the self-clean process operation reliability is improved, but the surface-to-surface attachment of the motor and plate assembly limits the available force
Solution Approach 1:
The patent replaces the flat surface-to-surface attachment with a tab-and-aperture engagement system that provides curved or rounded engagement surfaces. The tabs fit into the tapped apertures with radial engagement, creating a more robust mechanical connection that can better withstand the forces generated during latch hook operation and self-clean processes.
Solution Approach 2:
The patent transitions from a two-dimensional surface attachment to a three-dimensional engaged connection. The tabs extend from the motor and plate assembly and insert into the tapped apertures of the rear bracket, creating engagement in multiple dimensions. This dimensional change provides greater mechanical strength and force transmission capability for the latch hook pull-in force.
Data Source
AI summary
Provided is a long-bar latch assembly for an appliance such as an oven. The long-bar latch assembly is used during operation of a self-cleaning mode or function of the associated appliance. The long-bar latch assembly provided herein includes features that allows for accurate positioning of the long-bar latch assembly during servicing procedures. It also allows for appliance servicemen to conduct a simpler repair and operate in a more efficient manner when working to repair a long-bar latch assembly that has failed.