Centralized Single-Motor Headrest Adjustment for Backrest Stability
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Solution Overview
Problem
Existing backrests for seating furniture with headrest adjustment mechanisms suffer from instability, tilting, and potential damage during height adjustments due to multiple electric motors moving along with the headrest, especially in large headrest designs.
Innovation Solution
A single electric motor is centrally positioned between two guide rods, connected via a drive rod and bevel gear units, with spindle nuts guided in U-profiles to ensure synchronous movement and stability, eliminating the need for motors to move with the headrest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple electric motors are used to drive the headrest adjustment mechanism, then the driving force is sufficient, but the stability decreases and tilting or damage may occur during height adjustment
Solution Approach 1:
The patent combines multiple drive elements and their associated motors into a single integrated drive unit. This drive unit contains multiple drive rods that can be selectively engaged, allowing the system to achieve sufficient driving force through mechanical multiplication rather than using multiple independent motors, thereby maintaining stability.
Solution Approach 2:
The patent introduces a drive unit as an intermediary mechanism between the motor and the headrest adjustment system. This drive unit acts as a mediator that translates rotational motor motion into controlled linear motion of the guide rods through drive rods and engagement mechanisms, preventing direct motor movement that could cause tilting or instability.
2Adaptability or versatility
If electric motors move along with the headrest during height adjustment, then the adjustment range is increased, but the complexity and space requirements increase
Solution Approach 1:
The patent segments the adjustment mechanism into fixed and movable components. The drive unit with motors remains fixed while only the necessary drive rods and guide rods move during adjustment. This segmentation allows the headrest to achieve full adjustment range without requiring the entire motor assembly to move, reducing complexity and space requirements.
3Stability of the object's composition
If a single electric motor is used in a fixed position, then the stability increases and design is simplified, but the driving force distribution to multiple guide rods becomes challenging
Solution Approach 1:
The patent implements a dynamic drive mechanism where the single fixed motor can selectively engage multiple drive rods through movable engagement elements within the drive unit. This allows the system to adaptively distribute driving force to different guide rods as needed, maintaining stability while achieving complex motion patterns through controlled mechanical engagement rather than multiple fixed motors.
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 design enhances stability, prevents tilting and damage, allows for a more robust and space-efficient headrest adjustment mechanism, and supports large headrests effectively.
Implementation Method 1
The remainder of the drive has two bevel gear units, wherein each bevel gear unit is connected to the electric motor on the drive side in a torque-transmitting manner and to one of the drive components, each designed as a spindle, on the output side in a torque-transmitting manner
Implementation Method 2
each spindle interacts with a spindle nut corresponding to this spindle and mechanically connected to one of the two end faces of the lower crossbeam in a force-transmitting manner
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
The invention relates to a backrest (6) for a piece of seating furniture (2), comprising a base frame (10) and at least one headrest (8) arranged on the base frame (10), wherein the respective headrest (8) is held on the base frame (10) by means of a headrest adjustment device (12) of the base frame (10) and can be automatically moved back and forth between a lower height position of the headrest (8) and an upper height position of the headrest (8), and wherein the headrest adjustment device (12) has two guide rods (14, 16) movable along a vertical axis of the base frame (10) and spaced apart from each other for holding the headrest (8) and a lower crossbar (18) extending perpendicular to the guide rods (14, 16) and mechanically connected to the guide rods (14, 16), wherein the lower crossbar (18) is connected at both end faces of the lower crossbar (18) by a bearing extending along the vertical axis of the drive section (20) running along the base frame (10)22) a drive comprising an electric motor (24) of the headrest adjustment device (12) is connected in a force-transmitting manner, wherein the drive comprises only a single electric motor (24), the electric motor (24) being arranged in a fixed position substantially centrally between the two guide rods (14, 16) on an upper crossbeam (26) of the headrest adjustment device (12). The invention further relates to a piece of seating furniture (2).