Wheelchair Headrest Clamp Assembly for Precise Height Locking
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Solution Overview
Problem
Existing height-adjustable headrest devices for wheelchairs lack sufficient functional and operational safety, particularly in ensuring precise and secure attachment of the headrest support element to the crossbar element, leading to potential instability and misalignment.
Innovation Solution
A height-adjustable headrest device featuring a clamp connection with a centering bushing having external and internal threads, where the centering bushing is screwed into the retaining bracket's threaded bore, and a screw element is used to clamp the headrest support element to the crossbar element, ensuring precise mounting and preventing unintentional loosening, along with a spacer for wear-free clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple clamp connection is used to attach the headrest support element to the crossbar element, then the device complexity is reduced, but the reliability and manufacturing precision of the attachment are insufficient
Solution Approach 1:
A centering bushing is introduced as an intermediary component between the clamp connection and the crossbar element. This bushing features an external thread that engages with the clamp connection and an internal thread that engages with the headrest support element, providing precise alignment and secure attachment while preventing unintentional loosening through dual-thread engagement
Solution Approach 2:
The attachment system is divided into distinct functional segments: the clamp connection for clamping force, the centering bushing for alignment and thread engagement, and the headrest support element for structural support. This segmentation allows each component to perform its specific function optimally while maintaining overall system reliability
2Reliability
If a threaded connection is used to secure the headrest support element, then the reliability of attachment is improved, but the ease of operation for adjustment is reduced
Solution Approach 1:
The clamp connection incorporates a star-shaped adjustment mechanism that transforms rotational motion into linear clamping force. This dynamic mechanism allows the user to easily adjust the height by rotating the star handle, which moves the clamp along the threaded bore of the centering bushing, providing both ease of operation and secure attachment
3Device complexity
If direct clamping is performed without a spacer, then the device complexity is reduced, but wear and instability occur during operation
Solution Approach 1:
A spacer is positioned between the clamp connection and the headrest support element to provide cushioning and prevent direct metal-to-metal contact. This spacer prevents wear and tear during operation while maintaining the stability and precision of the attachment, addressing potential problems before they occur
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 provides a more precise and secure attachment of the headrest support element to the crossbar element, enhancing operational safety and stability by preventing unintended loosening and ensuring a precise fit, thus improving the overall functionality and usability of the device.
Implementation Method 1
a screw element which is screwed into the centering bushing
Implementation Method 2
a centering bushing, which has an external thread and an internal thread
Data Source
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AI summary
The device comprises a transverse bar, a head rest supporting element (4) and a clamp connection (100) for continuous adjusted fixing of the head rest supporting element at the transverse bar. The head rest supporting element is introduced in the recesses of a retainer, where the recesses are arranged one above the other. The transverse bar has a boring, which is introduced into a centering sleeve. The clamp connection is operated by screwing the screwing element in the centering sleeve, and head rest supporting element is introduced to the transverse bar. An independent claim is also included for a wheel chair with a height adjusting head rest device.