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Project 13: Adapted Tricycle


The purpose of our project is to modify a tricycle for a six-year-old boy who has varying control on his left side. Due to this varying control, we will need to focus on supporting his left side so that he can ride his trike without falling and hurting himself.
Dominic Alfini, Mikael Delelegn, Caden Holmes, Erik Jones, Roy Netlandsnes

Problem Statement

The main problem we face is that our child has varying motor control on the left side of his body and is unable to safely ride his trike without risk of falling off and being injured or being unable to control it on bad days. He also is unable to reach the pedals and handlebars easily due to the position of the seat being too far back. On bad days he also has difficulty turning or even holding onto the handlebars.

Design Specifications


  • A seat that can move forward and backward
  • Back support that can move forward and backward
  • Sides that can swing out and lock to allow entry/support while riding
  • Left-arm support to keep his arm close horizontal
  • Potential steering assistance

Technical Requirements

  • A sliding mechanism with a pop-out pin can allow 1 direction of movement
  • A bucket seat or spring locking mechanism can give side support
  • A motor or leveraging mechanism can give steering support

Background Research

The following is a company that specializes in modifications like these:

Discovery Series

Some of their designs have been looked at and considered for our designs. These include:

  • Pedal levelers
  • A secondary steering
  • Pin-held pedals to allow movement without pedaling if the pin is pulled.
  • Tilted seat with adjustment
  • Body-centered pedals

Concept Design 1

This design includes the following modifications:


The handles are curved fully. A vertical post could be used as hand support if the therapist thinks it’ll work well. A wrist and arm strap are located on the left side.


The seat has a push-out pin that can lock. This will allow the seat to move forward and backward as well as up and down. The back support is attached to the seat and can also move forward and back.


A single side support comes out of the seat to the left. It can be moved left and right as well as up and down.


A right-side flap support can swing and lock in place to give right-side support. This mechanism would have a spring force pulling it open. Once rotated all the way in, it would lock in place. Pushing back in would unlock it and allow it to open again. This is similar to the design of a retractable pen.


The left pedal will have foot straps to lock the boy’s feet in place while riding. If the therapist recommends, a string could be attached to the tip of both pedals. This will tilt one pedal up as the other tilts down.


Concept Design 2


The Handles of the previous design did not hold the Child’s hand in place comfortably. This design includes a glove that can be worn by the Child with a Velcro texture to attach to the handle. This allows for an adjustable grip position and added comfort


The Seat is attached to the frame via a slot and two bolts. one bolt is for stability while the second can be hand tightened using a knob to pinch the frame and hold it in place.

The seat also has a bucket-seat shape that keeps the Child from slipping out. The backrest can also be adjusted by the therapist as the Child’s needs change.


A armrest style support is used that folds up vertically and is attached at the back of the seat. The position of the hinge and armrest can be adjusted using a Allen key for quick modifications.


The current front wheel will be replaced with a lighter thinner wheel more suitable for indoor terrain. This reduces the effort needed to turn the handlebars and makes navigation smoother.


Concept Design 3


The design for the handles would be focused on full accessibility because on bad days our child is unable to open/close his hand well at all. It would consist of a rigid case for the hand that can open and clamp itself shut for easy hand insertion. There would also be an attached strap/handcuff style wrist constraint so that he can push and pull his arm and still turn the trike without having to hold the actual handle.


The seat would be a bucket style seat to support the sides of the child and assist in preventing him from falling off the trike. It would also have an adjustable pin in the style of modern weightlifting equipment with the handle on a rod to hold the seat into place.


The side support would act in the same way as the desk on auditorium seats (The seats in room 215). and would be easy to deploy as well as having the added benefit of being optional for days when the child does not need it.


The Pedals would be modified in such a way that it would be easier for a child’s foot to fit inside and would also lock to the ankle so that the bottom of the foot would not be needed to pedal.



2023 Spring