Design of a Linkage Based Articulating Wheelchair Legrest

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WPI, MQP, Articulating, Legrest, linkage, wheelchair


The goal of this project is to design an articulating elevating legrest, which will not interfere with the wheelchair function. Current designs for articulating wheelchair legrests do not provide the extension and elevation needed to reduce hip flexion and increase blood circulation. Existing products and patents for available articulating legrests are also not as durable as the non-articulating variety. A 2002-2003 MQP attempted a similar project with a manual wheelchair user as a client. The end product did not interface with the wheelchair and had other manufacturing problems, and now serves as a prototype for analysis. Evaluation of the prototype concluded that there was binding in the slider caused by a lack of planar motion and an insufficient bearing surface.To solve these problems, an articulating wheelchair legrest that consists of a planar six bar linkage coupled with a linear slider was designed and built. The linkage system accommodates the elevation motion while the linear slider system accommodates the extension motion. When compared to an articulating design developed by the student group in 2002-2003, this design decreases the overall size and weight and increases durability. The team concluded by suggesting few improvements for the device such as: machining the linear bearing system with greater precision and allowing it to self align more readily to reduce binding, incorporating a plastic shield to protect hands from moving the linkage, and placing an activation handle at the lower end of the housing for mechanical advantage.