Door Handle Lever Mechanism for High Torque Spring Return
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Solution Overview
Problem
Existing door handle fittings face challenges in generating high torque to move a handle to a rest position without spring fatigue, especially when the handle is heavy or has a battery compartment, requiring a spring that can maintain torque over a range of positions while being cost-effective.
Innovation Solution
A rotatable lever is connected to the handle and spring via a rotatable mounting, allowing for high torque transmission and mobility, with a spring carriage guiding the lever's movement and a damping element to manage torque changes, ensuring reliable rest position holding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a spring is used to move the door handle to a rest position, then the handle can be returned automatically, but the spring force decreases progressively and cannot generate sufficiently high torque for heavy handles
Solution Approach 1:
The patent applies the dynamics principle by making the spring force variable through the lever mechanism. The lever transforms the decreasing spring force into a more effective torque application throughout the handle's movement range. The spring carriage allows the lever to pivot at different positions, dynamically adjusting the mechanical advantage to maintain sufficient torque even as the spring relaxes, thereby preventing spring fatigue while reliably returning heavy handles to the rest position.
Solution Approach 2:
The lever acts as an intermediary between the spring and the handle. Instead of the spring directly acting on the handle, the lever mediates the force transmission. This intermediary mechanism allows the spring to generate high torque during initial compression while distributing the load more evenly throughout the movement, reducing peak stresses on the spring and preventing fatigue failure.
2Weight of moving object
If a heavy door handle with battery compartment is used, then the handle weight increases, but the spring torque required to move it increases proportionally
Solution Approach 1:
The lever mechanism with spring carriage provides dynamic mechanical advantage that scales with the handle weight. As the handle moves from actuated to rest position, the lever pivots on the spring carriage, continuously adjusting the force multiplication ratio. This allows the system to generate the necessary high torque for heavy handles with battery compartments without requiring an excessively strong spring, as the mechanical advantage is optimized throughout the movement range.
3Ease of manufacture
If a commercially available spring is used, then manufacturing costs are kept low, but the spring may not generate sufficiently high torque for heavy handles
Solution Approach 1:
The lever serves as a mechanical intermediary that amplifies the torque output of a standard commercially available spring. Instead of requiring an expensive, high-specification spring, the system uses the lever mechanism to multiply the force from an off-the-shelf spring, achieving the necessary torque for heavy handles while maintaining cost-effectiveness through the use of standard components.
Solution Approach 2:
The dynamic lever mechanism with spring carriage allows a standard spring to perform the work of a higher-specification spring. By adjusting the lever's pivot position on the spring carriage throughout the movement, the system optimizes mechanical advantage to extract maximum torque from a commercially available spring, eliminating the need for custom-engineered high-torque springs and reducing manufacturing costs.
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 enables reliable and cost-effective high-torque operation of the handle, maintaining torque over a range of positions without spring fatigue, ensuring secure rest position holding and efficient energy storage management.
Implementation Method 1
a spring for moving the handle into a rest position
Implementation Method 2
the fitting body having a spring for moving the handle into a rest position
Implementation Method 3
with a lever being arranged in the fitting body via which the spring acts on the handle
Implementation Method 4
The lever makes it possible to transmit sufficiently high torques to the handle
Implementation Method 5
The rotatable mounting can be limited to a rotation angle range
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a fitting (1) for a building door, comprising a handle (30), in particular a door handle, and a fitting body (2) for mounting on the building door, wherein the fitting body (2) has a spring (40) for moving the handle (30) into a rest position (I). According to the invention, a lever (42) is arranged in the fitting body (2), via which the spring (40) acts on the handle (30).