Tube Height Adjustment Locking With Rack and Eccentric Cam
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Solution Overview
Problem
Existing height adjustment devices for furniture, such as seating and tables, are difficult to use and often require coordination between two people due to lack of secure frictional connection and ease of setting the desired position.
Innovation Solution
A device with an outer tube and inner tube arrangement, featuring a toothed rack and engagement element with holding means at the outer tube's end, which creates a form-fitting connection through a resilient engagement element and eccentric mechanism to secure the inner tube relative to the outer tube, allowing easy adjustment and secure locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth outer tube surface is used, then the device has good appearance and easy cleaning, but frictional connection is insufficient and secure positioning cannot be achieved
Solution Approach 1:
The outer tube surface is segmented into different functional zones: smooth sections for appearance and cleaning, and textured/rugged sections for frictional engagement. This allows the tube to simultaneously achieve good appearance where needed and secure frictional connection where required for positioning.
2Strength
If a toothed rack and engagement element are added, then form-fitting connection and pressure resistance are improved, but the device complexity increases
Solution Approach 1:
The engagement element combines multiple functions in a single component: it has teeth for form-fitting engagement with the toothed rack, a resilient body for automatic engagement/disengagement, and integration with the holding means. This merging reduces the need for separate components while achieving both pressure resistance and controlled operation.
Solution Approach 2:
The engagement element serves multiple purposes: providing form-fitting connection through teeth, absorbing pressure loads, enabling easy release through resilient deformation, and preventing tube twisting when integrated with holding means. This multi-functionality reduces overall device complexity despite adding capability.
3Reliability
If holding means are added to prevent twisting, then operational reliability is improved, but device complexity increases
Solution Approach 1:
The holding means are integrated with the engagement element into a unified structure. The holding means serve dual purposes: preventing tube twisting during operation and providing support for the engagement element. This integration achieves enhanced reliability without proportionally increasing complexity.
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 enables easy, secure, and reliable height adjustment of furniture, ensuring the inner tube remains fixed relative to the outer tube under pressure, while allowing variable length adjustment without pressure, enhancing operational reliability and user experience.
Implementation Method 1
an engagement element, which can be displaced perpendicularly to the axis of the pipes and has teeth for engaging in the toothed rack, is arranged resiliently on the holding means
Implementation Method 2
an eccentric pivotable about an axis of rotation is arranged on the holding means, which is used to exert pressure on the back of the engagement element
Data Source
Figure 1~2
AI summary
The mechanism has a base pin (1) sleeved with an extension tube (2). A thin neck (31) is fixed in a shell (3), and an elastic pressing block (4) is fixed in the thin neck. A locking part (41) i.e. bump gear, is fixed on a bottom plane of the elastic pressing block. The shell is provided with a roof pressure part (5) i.e. eccentric cam spanner, is used for limiting the elastic pressing block in the thin nick. The extension tube is formed with an open slot (21). A bump (22) i.e. rack, is matched with the locking part and embedded in the open slot.