Reinforced Door Fitting Back Plate for Retrofit Mounting Strength
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Solution Overview
Problem
Existing back plate assemblies for door fittings face challenges in maintaining security class during retrofitting with electronic door fittings, as they often compromise strength to achieve compatibility with various attachment types, potentially exceeding deformation limits in tensile tests and losing safety class.
Innovation Solution
A back plate assembly design featuring a combination of elongated holes, screw holes, and a reinforcing plate made of high-strength material, along with conical insert washers, which enhances strength and distributes pressure evenly, ensuring compatibility with multiple attachment types while meeting security class requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If numerous perforations are provided in the back plate assembly to ensure compatibility with various installation methods, then adaptability is improved, but strength decreases and maximum permissible deformations during tensile testing may be exceeded
Solution Approach 1:
The back plate assembly is divided into a plate element and a separate reinforcement element that can be selectively positioned and attached. This segmentation allows the reinforcement element to compensate for strength losses caused by multiple perforations in the plate element, resolving the contradiction between adaptability (needing many holes) and strength (needing intact material).
Solution Approach 2:
The back plate assembly combines two distinct elements: a plate element providing adaptability through multiple perforations and a reinforcement element providing additional strength. This composite structure allows both perforations for various installation methods and sufficient strength to meet tensile testing requirements coexist.
2Adaptability or versatility
If a continuous recess or slotted hole extending over a large area is used for attachment points along the longitudinal center plane, then adaptability is improved, but strength problems occur
Solution Approach 1:
The reinforcement element is designed with discrete reinforcement portions that can be selectively positioned at specific locations rather than creating a continuous reinforcement structure. This allows material webs to remain between reinforcement areas, maintaining strength while providing flexible attachment options.
Solution Approach 2:
The reinforcement element provides localized strengthening at specific areas where needed, rather than uniformly reinforcing the entire back plate. This local quality approach maintains overall strength while allowing adaptability through selective reinforcement placement.
Data Source
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AI summary
The present invention relates to a backplate assembly (50) for a door fitting (12), comprising a first pair of holes (60), wherein the first pair of holes (60) is formed by a first elongated hole (58) and a first screw hole (56), the first elongated hole (58) extending along a longitudinal median plane (32) of the backplate assembly (50), and wherein the first screw hole (56) is arranged on the longitudinal median plane (32), a second pair of holes (66), wherein the second pair of holes (66) is formed by a second screw hole (62) and a third screw hole (64), the second screw hole (62) and the third screw hole (64) being opposite each other with respect to the longitudinal median plane (32), and a third pair of holes (72), wherein the third pair of holes (72) is formed by a fourth screw hole (68) and a fifth screw hole (70).wherein the fourth screw hole (68) and the fifth screw hole (70) are arranged on the longitudinal center plane (32) and between the first screw hole (56) and the first elongated hole (58). Furthermore, a door fitting (12) with such a backplate assembly is proposed. (Fig. 8)