Wheelchair Tilt Linkage for Center-of-Gravity Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wheelchair tilt arrangements fail to maintain the center of gravity during posterior tilt, leading to instability and the risk of tipping over.
Innovation Solution
An electric wheelchair with a tilt arrangement featuring a lift device, a tilt frame, and pivotally coupled arms that adjust the orientation of the tilt frame, maintaining stability by minimizing changes in the center of gravity during tilting, and allowing for more compact design and flexible battery placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tilt arrangement is provided in the wheelchair, then the seat orientation can be adjusted for comfort and control, but the centre of gravity changes during tilting causing instability and risk of tipping
Solution Approach 1:
The patent employs a counterbalance mechanism where a counterweight member is coupled to the tilt frame through a linkage system. As the tilt frame rotates to adjust seat orientation, the counterweight moves in opposition to compensate for the changing center of gravity, thereby maintaining wheelchair stability during tilting operations
2Adaptability or versatility
If multiple actuators and levers are used to provide tilt and lift functions, then comprehensive seat adjustment is achieved, but the device complexity increases
Solution Approach 1:
The patent integrates multiple functions into a unified mechanism. The tilt actuator controls both the tilt frame orientation and the counterweight position through their mechanical coupling. The linkage system serves dual purposes: transmitting tilt motion and positioning the counterweight, thereby reducing the need for separate actuators for each function
Solution Approach 2:
The patent combines the tilt mechanism and counterbalance mechanism into an integrated assembly. The tilt frame, counterweight member, and linkage elements are coupled to form a unified system where single actuator operation simultaneously achieves seat orientation adjustment and center of gravity compensation
Data Source
AI summary
The present disclosure relates to a wheelchair (1) with tilt capabilities. The electric wheelchair comprises a chassis (3), a lift device having a base member which is fixedly arranged to the chassis, and a lifting member arranged to move rectilinearly relative to the base member along an axis defined by a longitudinal extension of the lifting member, a tilt frame, a first arm pivotally coupled to the lifting member and the tilt frame, and a second arm coupled to the base member, and which second arm is pivotally coupled to the first arm forming a pivot connection, wherein movement of the lifting member towards the extended position moves the pivot connection towards the base member and movement of the lifting member towards the retracted position moves the pivot connection away from the base member.