Bicycle Rack Movable Frame Vertical Stroke Design
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Solution Overview
Problem
Existing bike racks for caravans and campervans require lifting activities for loading and unloading, which can be strenuous and injurious, especially for elderly users, and often limit the vertical stroke and obstruct rear lights and license plates.
Innovation Solution
A rack design featuring movable guides at an intermediate distance from each other, engaging with a stationary guide to achieve a large vertical range, using rollers for minimal friction and stability, and a cable-winch system for easy operation, allowing the vehicle to be wheeled onto the support without lifting, while maintaining visibility of rear lights and license plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a stationary frame with a movable frame and sliding connections is used, then the rack structure is simple, but the vertical stroke is limited and lifting activities are still required
Solution Approach 1:
The rack system transitions from a static structure to a dynamic one by introducing a movable frame that can be positioned at different heights along the stationary guide. The movable frame is connected to the stationary frame through guides and cables, allowing it to move vertically and be locked at various positions, thereby providing both a large vertical stroke and ease of operation.
Solution Approach 2:
Cables and pulleys are introduced as intermediary elements to transfer the lifting force from the winch to the movable frame. This intermediary mechanism allows the user to lift the movable frame with minimal effort by winding the cable onto the winch, significantly reducing the direct lifting activity required.
2Length of moving object
If the stationary guide extends far above the vehicle to achieve large stroke, then the vertical range increases, but rear lights and license plate become obscured
Solution Approach 1:
The guide system is segmented into a stationary guide attached to the vehicle and a separate movable frame. The stationary guide can extend upward to provide the necessary vertical stroke, while the movable frame is positioned only when needed for loading and unloading. This segmentation allows the stationary guide to extend high without permanently obstructing rear lights and license plate, as the movable frame can be retracted or positioned to the side when not in use.
3Ease of operation
If a complex swivelling support mechanism is used, then lifting activities are reduced, but the rack structure becomes expensive
Solution Approach 1:
The complex swivelling mechanism is extracted and replaced with a simpler cable-winch system. Instead of using a complex mechanical swivelling support, the invention uses cables attached to the movable frame that are wound onto a winch, providing the necessary lifting function with a much simpler and more cost-effective mechanism.
Solution Approach 2:
The complex mechanical swivelling support system is replaced with a cable-winch mechanism. This substitution uses a simpler mechanical system (cables and pulleys) combined with a winch to achieve the same lifting function, thereby reducing structural complexity and cost while maintaining ease of operation.
4Ease of operation
If rollers are used for the movable guides, then friction is minimized and movement is smooth, but manufacturing precision requirements increase
Solution Approach 1:
The guide engagement parameters are optimized by specifying that the movable guides engage the stationary guide at two distinct locations along its length. This dual-point engagement changes the geometric parameters of the system, providing both stability and smooth movement while accommodating reasonable manufacturing tolerances. The rollers are positioned to engage at these specific points, balancing smooth operation with manufacturability.
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 design minimizes lifting activities, provides a large vertical stroke, maintains visibility of rear lights and license plates, and is cost-effective and lightweight, ensuring easy loading and unloading without obstructing the vehicle's rear space.
Implementation Method 1
a cable-winch system for easy operation, allowing the vehicle to be wheeled onto the support without lifting
Implementation Method 2
using rollers for minimal friction and stability
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
Rack (1) for transporting vehicles for one or two persons, which vehicles are provided with wheels, in particular bicycles, the rack being provided with means for fastening the rack to the rear side of a main vehicle, such as a caravan or a campervan, comprising a stationary frame (2) provided with the fastening means (13), which frame comprises at least one elongated substantially upwardly extending preferably substantially vertical stationary guide (4a,4b), and a movable frame (3) that is provided with means (34) for supporting one or more vehicles for one or two persons, wherein the rack is provided with means (16) for moving the support means (34) up and down along the guide between a lowered position in which a vehicle for one or two persons can be placed on the support means or be removed therefrom and a transport position situated at a higher level, wherein the movable frame (3) is provided with guides (5a,5b) moving along with it for guided engagement onto the outer surface of the stationary guide at the stationary frame (2), which movable guides (5a,5b) comprise a first and a second guide, which in guide direction are situated at a, preferably constant, intermediate distance from each other which guides preferably comprise one or more rollers.