Furniture Ejection Device with Backstop and Speed-Dependent Damping
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Solution Overview
Problem
Existing ejection devices for movable furniture parts, such as drawers, often fail to ensure reliable and controlled opening and closing movements, especially with heavier loads, due to insufficient friction and clamping forces, leading to inconsistent ejection speeds and potential premature ejection during the charging process.
Innovation Solution
The ejection device incorporates a backstop mechanism to prevent movement until the spring is fully tensioned and an opening damping system that generates speed-dependent damping forces to control ejection speed, using a combination of toothed racks, pinions, and rotary or linear dampers to manage the movement of furniture parts, ensuring consistent performance across varying loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking device with clamping element and abutment section is used to prevent premature ejection, then the furniture part can be secured during spring tensioning, but the friction and clamping forces are insufficient especially with heavier furniture parts
Solution Approach 1:
A backstop is introduced as an intermediary mechanical element between the furniture part and the spring system. The backstop provides a rigid stopping surface that physically blocks premature ejection movements, transferring the full spring force to the backstop structure rather than relying on friction-based clamping forces. This mediator approach allows the locking mechanism to handle heavy loads without requiring proportionally higher clamping forces.
2Ease of operation
If no opening damping mechanism is provided, then the ejection device structure is simpler, but the ejection speed varies significantly with load weight causing inconsistent handling
Solution Approach 1:
A rotary damper is integrated into the pinion mechanism to provide speed-dependent damping forces during ejection. The damping force automatically adjusts based on ejection speed: higher speeds generate higher damping forces, and lower speeds generate lower damping forces. This dynamic response ensures consistent ejection characteristics across varying load weights without requiring complex control systems or multiple adjustable components.
Solution Approach 2:
The opening damper is designed to automatically regulate ejection speed through its inherent speed-dependent damping characteristics, without requiring external control inputs or adjustments. The system self-adjusts to maintain consistent handling across different load conditions, eliminating the need for manual intervention or complex control mechanisms.
3Power
If the spring directly ejects the furniture part without damping control, then the energy transfer is more efficient, but light furniture parts are accelerated too strongly while heavy parts are not ejected with sufficient speed
Solution Approach 1:
The rotary damper changes the effective damping parameter dynamically during ejection based on speed. At high ejection speeds, the damper generates strong opposing forces to limit acceleration. As speed decreases, the damping force automatically reduces, allowing the spring to complete the ejection stroke. This parameter change approach maintains consistent ejection performance across different load weights while preserving energy efficiency.
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
This solution allows for consistent and controlled ejection speeds regardless of load weight, enabling smoother handling of furniture parts by preventing premature ejection and allowing for controlled resumption of closing movements, thus enhancing user experience and operational reliability.
Implementation Method 1
a drive element that is prestressed by at least one spring and by means of which the movable furniture part can be moved from a closed position to an open position
Implementation Method 2
which generates damping forces for braking the movable furniture part when the movable furniture part is ejected
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to an ejection device (6, 6') for a moveable furniture part (3) comprising a drive element (19, 19') pretensioned by at least one spring (15), by means of which the moveable furniture part (3) can be moved from a closed position into an open position, wherein, with a closing or opening movement of the furniture part (3) along a path, the at least one spring (15) can be moved into a tensioned position and the furniture part (3) can be engaged in the closed position with the at least one tensioned spring (15), wherein a return stop is provided that limits a closing or opening movement of the moveable furniture part (3), when the tensioning of the spring (15) during a closing or opening movement of the furniture part (3) is not yet completed, and wherein an opening damper is provided which generates damping forces for decelerating the moveable furniture part (3) during the ejection of the moveable furniture part (3). The invention also relates to a piece of furniture comprising an ejection device of this type, and to a method for opening and closing a moveable furniture part (3).