Universal Return Spring Mechanism for Door Fittings
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Solution Overview
Problem
Existing return spring devices for door and window fittings are complex, expensive to manufacture, and limited in their universality, requiring skilled assembly and being specific to either right-hand or left-hand versions with restricted operating angles.
Innovation Solution
A return spring device with a driver element mounted in a housing that can rotate against a restoring force, featuring a central recess with radially adjacent arcuate recesses and a stop element, allowing universal use and larger operating angles, and comprising a few components for simple and efficient production and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional return springs are added to door locks to return heavy handles to initial position, then the handle return reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the return spring function with the existing lock spring mechanism by having the lock spring act directly on the lock follower. This integration eliminates the need for separate return springs for the lock follower, reducing component count while maintaining reliable return function for both handle and lock follower.
Solution Approach 2:
The lock spring serves multiple functions: it returns the lock follower to initial position and also provides return force for the handle through mechanical coupling. This multi-functionality reduces the need for dedicated return springs, simplifying the overall device while improving reliability.
2Ease of manufacture
If return spring devices are designed for specific right-hand or left-hand versions with limited operating angles, then the manufacturing and assembly process is simplified, but the adaptability and universality of the fitting is reduced
Solution Approach 1:
The patent designs the lock follower and return spring mechanism to be version-independent, allowing the same component to be used for both right-hand and left-hand fittings. The square pin and lock follower geometry enable universal application regardless of handle orientation, eliminating the need for separate right-hand and left-hand versions.
Solution Approach 2:
The patent employs asymmetric design elements such as the square pin with specific orientation features and the lock follower geometry that accommodate both clockwise and counter-clockwise handle operations. This asymmetric yet universal design allows single-component compatibility across different fitting configurations.
3Reliability
If complex return spring arrangements with multiple components are used, then the handle return function is ensured, but the assembly work and skill requirement increase
Solution Approach 1:
The patent merges the return spring function into the existing lock spring mechanism, eliminating the need for separate return spring installations. The lock spring is already part of the standard lock assembly, so no additional components need to be assembled, reducing assembly complexity while ensuring reliable return function.
Solution Approach 2:
The lock mechanism itself provides the return function through its inherent spring-loaded lock follower that automatically returns to initial position. This self-service mechanism eliminates the need for external return spring installations and complex assembly procedures, making installation straightforward while ensuring reliable operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective, easy-to-assemble return spring device that can be used universally for both right-hand and left-hand fittings, offering larger operating angles and reliable handling, thus overcoming the limitations of prior art.
Implementation Method 1
The restoring force is generated by a spring element
Implementation Method 2
DE 100 52 495 A1 discloses a fastening device for a rotary window and/or door handle... the compression spring also being designed as a torsion spring in order to bring the rotary door handle back into its horizontal position
Data Source
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AI summary
The arrangement has a drive element (40) rotatably mounted in a housing against a spring (50) restoring force with a rectangular opening for a pin able to turn with at least one rotatable handle of the fitting. The housing has a shell (21) with a central opening for the drive and spring elements and two cut-outs (30,34) between which a stop element (26) for the spring element is formed. An independent claim is also included for a door fitting.