Device for a seat and seat
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Solution Overview
Problem
Existing seating furniture devices with leg rests are bulky, require excessive material and weight, and lack efficient guidance mechanisms for the leg rest movement between rest and operating positions.
Innovation Solution
The device features a design where the actuating arm with a roller and guide ramps ensure force-transmitting contact only at the beginning and end of leg rest movement, with a stationary electric motor, and a base frame using U-profiles and bevel gears for simplified and robust construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous force-transmitting guidance is provided along the entire movement path of the leg rest, then guidance reliability is improved, but device complexity and material requirements increase
Solution Approach 1:
The guidance function is segmented into discrete locations rather than continuous guidance. Guide ramps are positioned only at the beginning and end of the movement path, dividing the guidance task into specific segments where force transmission is actually needed for positioning accuracy.
Solution Approach 2:
Force-transmitting guidance is applied locally only where necessary - at the start and end positions of the leg rest movement. The guide ramps provide localized guidance quality at critical points while leaving the intermediate movement path without active guidance, reducing overall device complexity.
2Manufacturing precision
If more material is used for the actuating arm and guide ramps, then guidance precision is improved, but device weight increases
Solution Approach 1:
The guidance system is segmented to provide precision only at critical locations (start and end positions) rather than along the entire movement path. This allows using material efficiently only where guidance precision is actually needed for positioning.
Solution Approach 2:
Instead of providing full continuous guidance, the system uses partial action by limiting force-transmitting contact to only the beginning and end of the movement. This partial guidance approach achieves sufficient positioning precision without the material requirements of complete continuous guidance.
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
Achieves reliable and space-efficient leg rest movement with reduced material and weight, allowing the leg rest to be stored invisibly beneath the seat in the rest position and positioned in front of the seat in the operating position, enhancing stability and durability.
Implementation Method 1
the roller is only in force-transmitting contact with one of the two guide ramps at the beginning and end of each movement and is otherwise without any force-transmitting guidance
Implementation Method 2
the actuating arm with the roller is, on the one hand, movable in engagement with the respective guide ramp following a contour of this guide ramp and can be held in both the rest and operating positions, and, on the other hand, is held on the retaining linkage by gravity by means of a stopping device of the retaining linkage
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The invention relates to a device (6) for a piece of seating furniture (2), comprising a base frame (10) for attaching the device (6) to an underside of a seat part (4) of the seating furniture (2), a leg rest (8), and an adjustment device (14) comprising an electric motor (12) for attaching the leg rest (8) to the base frame (10) and for electrically moving the leg rest (8) from a rest position to a working position and vice versa, wherein the leg rest (8) is arranged completely below the seat part (4) in the rest position and completely in front of the seat part (4) in the working position, and wherein the adjustment device (14) has at least one actuating arm (18) having a roller (16) at its free end and two guide ramps (20, 22) for force-transmitting guidance of the respective roller (16), wherein the at least one actuating arm (18) with the roller (16) and the corresponding guide ramps (20, 22)22) are designed and arranged in such a way that the roller (16) is in force-transmitting contact with one of the two guide ramps (20, 22) only at the beginning and end of the respective movement when the leg support (8) is moved from the rest position to the operating position and vice versa, and is otherwise without any force-transmitting guidance. Furthermore, the invention relates to a piece of seating furniture (2).