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The goal of this project is to design a device that can assist a set of infants in learning to crawl. We will analyze multiple designs to find the one that best suits our use case.
There are two infants who are getting ready to crawl but do not have the strength or coordination to do so. The children need an assistive device that can reliably support their weight and allow them to crawl unobstructed.
-Frame: It must support the weight of the children, without obstructing their range of motion. It must also fit through doorways as small as 29 inches.
-Harness: the harness must be able to be adjusted to fit both children, and support their torso and head. the harness will need to be removed so that it can be washed.
-Wheels: the wheels must be able to roll over small obstacles, such as thresholds in the house.
-Strength: the frame and harness must be able to support the weight of the children, preferably with room to grow.
-Weight: the entire device must be light enough to be moved by an infant.
For background research/Inspiration, we focused mainly on one device called the Creepster Crawler. This product most closely fit our initial ideas and was suggested to us by the family. It utilizes a 7-point adjustable harness suspended by a 4-wheeled frame. It does not however, provide any head and neck support.
Concept 1 is a 4-wheeled frame that features adjustable legs. The legs can be adjusted to different angles to control the width of the frame and allows easier storage. the harness is attached to the frame using adjustable clips so that it can also be removed. The head support is separate from the body harness so that it can be removed when no longer needed, and features a “ring pad” so that the child can still see through the harness.
Concept 2 is a circular frame with 4 legs attached at the top, and wheels attached at the base. This design features a stance-assist bar on either side so that way the children can progress from crawling to standing. The harness design for this concept is also different. It is more of a large “hammock” rather than a dedicated harness. It features 2 arm and leg holes as well as a face hole for added neck and head support.
Concept 3 is similar to the other designs, the only difference being that it is not a circular nor rectangular frame. The “legs” are connected to each other in order to make it foldable and easier for storage. This design also features a harness so the baby can move freely, with the upper body being the only part of the body being attached to it.
We did not proceed with any of our initial concept designs, but combined multiple favored features from each.
We decided to create the most simple version of our concept designs, minimizing complexity to save weight; focusing primarily on efficiency for both the child and the parents.
The design will be constructed out of two bent, single-piece arches, connected by multiple horizontal support beams. The entire frame will be made out of 1-inch diameter 6061-T6 aluminum tubes with a wall thickness of 0.065 inches to keep the frame as light as possible. There will be four 2-inch casters, one on each corner. The harness will be connected to the frame in seven different locations using adjustable buckles so that the lengths can be changed and the harness can be removed for easy cleaning. There will be two sideways holes in the harness so that when the child gets old enough the device can be rotated and used as a walker as well.
By using an estimated possible weight that a child might weigh while using our device, the summation of forces in the y-direction, the moment of stress about the upper bars where the straps will attach, and the factor of safety could be found. Our calculated factor of safety is 8.21.
Calculating the total volume of aluminum used in the frame and multiplying by the approximate density of 6061-T6 aluminum, we can find the expectedd weight of the aluminum frame.
Calculating the deflection in the Aluminum and force required to bend
After final assembly we tested to confirm that the frame was very easy to roll along the ground, and that it could support our weight without any signs of stress.
The child should be put inside of the harness, and the harness should be adjusted for a comfortable fit ensuring that the height from the ground is set per recommendations of the physical therapist
We did have to deviate from our initial concept designs, to ensure that the crawl assist device was as simple and light as possible. However we believe the final design does include all of the necessary adjustable elements to accommodate the children. Overall, we were able to complete the project for around half the price of a similar retail device. We hope that this will be the tool the family needs to aid with the children’s development.
