Ejection device for a movable furniture part and piece of furniture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ejection devices for movable furniture parts, such as drawers, struggle to absorb high holding forces and prevent reverse movement without damaging components, especially with heavier loads, due to insufficient friction and clamping forces.
Innovation Solution
The ejection device incorporates a backstop mechanism with a pinion and toothed rack system, where the pinion is guided in a guideway and locked via a locking element, providing high holding forces and preventing reverse movement by engaging with the toothed rack, allowing for smooth operation without noticeable acoustic or haptic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamping element is wedged with an abutment section to prevent opening movement, then the furniture part can be locked, but the friction and clamping forces are insufficient for heavier furniture parts
Solution Approach 1:
The patent replaces the insufficient friction-based clamping mechanism with a positive engagement rack and pinion system. The pinion engages with the rack through toothed mechanical interlocking, providing high holding forces through gear meshing rather than relying on friction alone. This mechanical substitution enables the system to securely hold heavy furniture parts that would exceed the capacity of simple clamping elements.
2Reliability
If a locking device is used to prevent ejection before energy store loading is complete, then the furniture part can be secured, but the device complexity increases
Solution Approach 1:
The patent combines the backstop function and locking mechanism into a single integrated rack and pinion assembly. The rack serves dual purposes: as a guide for the pinion movement and as the locking element itself. The pinion's engagement with the rack provides both the backstop function (preventing over-travel) and the locking function (securing the furniture part), eliminating the need for separate clamping elements and reducing overall device complexity.
Solution Approach 2:
The rack and pinion system performs multiple functions simultaneously: it acts as a backstop to limit travel, a locking mechanism to secure the furniture part, and a guide for controlled movement. This multi-functionality reduces the number of separate components needed, simplifying the overall device while maintaining reliable ejection prevention and positioning capabilities.
3Force
If high holding forces are provided to prevent reverse movement of heavy drawers, then the furniture part can be securely held, but the parts of the backstop may be damaged
Solution Approach 1:
The patent replaces the vulnerable backstop components with a robust rack and pinion gear system designed to handle high loads. The toothed engagement distributes forces across multiple contact points between rack and pinion teeth, preventing stress concentration that would damage simple backstop structures. This mechanical system is specifically engineered to absorb and transmit high holding forces required for heavy furniture parts without component failure.
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 effectively absorbs high holding forces, prevents reverse movement of heavy furniture parts, and ensures secure latching and quick release, maintaining a simple design that does not damage components.
Implementation Method 1
a drive element which 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
the backstop having a pinion guided in a guideway which, in the case of an opening or closing movement is in engagement with a toothed rack and can be fixed via a locking element
Implementation Method 3
the locking takes place via a connection of the pinion or a gear wheel and the toothed rack, so that high holding forces are provided
Implementation Method 4
the pinion can be moved together with a carriage relative to a guide track on a housing, with the engagement of the pinion on the toothed rack not being noticeable to the user either acoustically or haptically
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to an ejection device (6, 6') for a movable furniture part (3) comprising a drive element (19, 19'), which is preloaded by at least one spring (15) and by means of which the movable furniture part (3) can be moved from a closed position into an open position, wherein the at least one spring (15) can be moved into a loaded position during a closing or opening motion of the furniture part (3) along a displacement distance and the furniture part (3) can be locked with the at least one loaded spring (15) in the closed position, wherein a backstop is provided, which limits a closing or opening motion of the movable furniture part (3) if the loading of the spring (15) during a closing or opening motion of the furniture part (3) is not yet concluded, wherein the backstop has a pinion (14) guided in a guide track (12, 12'), which pinion engages with a gear rack (11, 11') during a closing motion and can be locked by means of a locking element (17). The backstop can thus absorb high holding forces.