Furniture Pull-In Lever Damping for Smooth Self-Closing Retraction
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Solution Overview
Problem
Existing retraction devices for extendable furniture parts lack efficient damping mechanisms in the final section of the retraction path, leading to inadequate control over the retraction movement and potential damage from high braking forces.
Innovation Solution
A retraction device featuring a pull-in lever system with a stationary pivot axis, a driver that interacts with the pull-in lever, and a common damping device comprising a viscous damping medium and a mechanically acting braking device, where the braking force is dependent on the rotational speed, providing a compact and cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piston-cylinder unit damper is used for damping retraction movement, then damping effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the damping function from the complex piston-cylinder unit and implements it through a simpler friction-based mechanism. The friction damper consists of a friction element and a friction pairing element, eliminating the need for pistons, cylinders, and pneumatic systems while achieving effective damping of the retraction movement.
Solution Approach 2:
The patent employs a friction damper with simple friction elements that can be easily manufactured and replaced. The friction-based mechanism uses basic mechanical components rather than expensive pneumatic or hydraulic systems, reducing both initial cost and maintenance expenses while providing sufficient damping functionality.
2Device complexity
If a friction damper is used for damping retraction movement, then device complexity is reduced, but braking force becomes independent of speed
Solution Approach 1:
The patent introduces a spring element that dynamically adjusts the normal force between the friction elements. As the retraction speed changes, the spring compression varies, thereby adjusting the normal force and consequently the frictional braking force. This creates a speed-dependent damping effect while maintaining mechanical simplicity.
Solution Approach 2:
The patent changes the parameter of normal force between friction elements by incorporating a spring mechanism. The spring allows the normal force to vary with the retraction speed and position, transforming a static friction system into a dynamic one where braking force adapts to operational conditions without increasing device complexity.
3Ease of operation
If high braking forces are applied in the final section of retraction path, then retraction control is improved, but risk of damage increases
Solution Approach 1:
The patent applies damping forces progressively throughout the retraction path, with the friction damper and spring mechanism providing increasing braking force as the furniture part approaches the fully retracted position. This gradual cushioning prevents sudden high-impact forces that could cause damage, while still ensuring controlled stopping at the final position.
Solution Approach 2:
The patent converts the potentially harmful high impact force into a beneficial controlled deceleration process. The friction damper dissipates kinetic energy through controlled friction, and the spring mechanism stores and releases energy to provide smooth deceleration, transforming what would be a damaging impact into a gentle, controlled stopping action.
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 effectively dampens the retraction movement, ensuring smooth operation and reducing the risk of damage by adjusting braking force based on speed, making it suitable for heavy-duty applications.
Implementation Method 1
a common damping device (14) which dampens the retraction movement of the at least two extendable furniture parts (1) in the last section of its retraction movement
Implementation Method 2
which when pulling out the respective pull-out furniture part is moved by the associated driver between a basic position, which is the pull-in lever in the retracted position state of the extendable furniture part assumes, and a waiting position in which the driver decouples from the pull-in lever
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A pull-in device for at least two pull-out furniture parts (1), which can be pulled out of a furniture body (8) from a fully retracted position into a fully extended position in a pull-out direction (7) and can be moved into the furniture body (8) in the opposite direction to the pull-out direction (7). are, comprises for each of the pull-out furniture parts (1) a driver (2) which is displaced when the pull-out furniture part (1) is pulled out in the pull-out direction (7) and when the pull-out furniture part (1) is retracted against the pull-out direction (7) and for each of the extendable furniture parts (1) have a pull-in lever (5) acted upon by a pull-in spring (10), which when the respective pull-out furniture part (1) is pulled out by the associated driver (2) between a basic position, which the pull-in lever (5) in the pushed-in state of the pull-out furniture part (1) occupies, and a waiting position in which the driver (2) decouples from the pull-in lever (5) when the pull-out furniture part (1) is pulled out, and can be pivoted about a stationary pivot axis (6). Each of the pull-in levers (5) can be coupled to and uncoupled from a brake shaft (12) by means of a respective coupling device (30), the rotation of the brake shaft (12) being dampened by a damping device (14).