Wheelchair Mounting Unit with Threaded Drum Assembly
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Solution Overview
Problem
Existing mounting units for wheelchairs are either cumbersome and heavy due to form-fitting connections or lack resilience and durability due to clamped connections, and often require many parts, making them complicated and inefficient for adjustable and loadable applications.
Innovation Solution
A mounting unit utilizing a drum receiving unit with a female thread and a drum assembly with a male thread, along with a bolt, that provides a detachable form fit and force fit connection, allowing for adjustable alignment and increased resilience and loadability with fewer parts, enabling continuous and step-less adjustment of add-on pieces like caster wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If form-fitting connections (gears or bolts in hole patterns) are used for highly loaded and angle-adjustable attachments, then the connection strength and load-bearing capacity are improved, but the weight and bulkiness of the construction increase
Solution Approach 1:
The patent combines form-fitting connection elements (polygonal cross-section drum assembly fitting into drum receiving unit) with threaded fastening (male and female threads on bolts) into a single integrated mounting mechanism. This merging allows the connection to achieve both high strength through the polygonal form-fitting interface and adjustable angular positioning through the threaded bolt, while avoiding the need for separate heavy gear mechanisms or multiple bolt patterns that would increase weight.
2Weight of moving object
If clamped connections are used for less demanding loads, then the weight is reduced, but the resilience and durability of the connection deteriorate
Solution Approach 1:
The drum assembly features a polygonal cross-section (a form of curved/geometric shape) that fits into a corresponding receiving unit. This geometric interface provides a resilient, durable connection that can accommodate manufacturing tolerances and provide mechanical interlocking, while being lighter than traditional form-fitting gear connections. The curved/polygonal interface distributes loads more effectively than flat clamped surfaces.
3Adaptability or versatility
If form-fitting connections and clamped connections are used together, then the adaptability and adjustability are improved, but the device complexity and number of parts increase
Solution Approach 1:
The mounting unit employs a universal interface design where the drum assembly with polygonal cross-section and threaded bolt can simultaneously provide form-fitting engagement for angular adjustment and threaded fastening for secure attachment. This multi-functional interface replaces the need for separate form-fitting mechanisms (gears, multiple hole patterns) and clamped connections, reducing the total number of parts while maintaining full adjustability and adaptability.
Data Source
AI summary
A mounting unit for adjustably mounting an add-on piece to a frame, in particular of a wheelchair, includes at least one drum receiving unit having at least one aperture and female thread. The drum receiving unit is an integral part of the frame or adapted to be attached to the frame. At least one drum assembly has at least one hole and a male thread. At least one bolt is part of the add-on piece or adapted to be mounted therewith to hold the add-on piece. The drum receiving unit is adapted to receive the drum assembly. The female thread mates with the male thread and allows an alignment of the position of the hole with respect to the aperture, such that the bolt can be inserted through the aperture at least partly into the hole. The drum receiving unit with the drum assembly and/or the drum assembly with the bolt comprises a detachable form fit connection. At least one of the drum receiving unit, the drum assembly and/or the bolt comprises a detachable force fit connection with respective mating component.