college of engineering white

Project 6: Sensory Swing

Abstract

The purpose of this project is to create a sensory swing for a young child with developmental issues. Due to a lack of space in the home, the swing will be mounted in a doorway. The primary purpose of the swing is to provide a place where the child can be exposed to unfamiliar or disliked textures. However, the mother would also like to be able to sit in the swing with her son.

Mason Baines, Erica Wiles, Carrington Little, Alex Tharpe, Eli Hudson

Problem Statement

The purpose of this project is to create a sensory swing for a young child with developmental issues. Due to a lack of space in the home, the swing will be mounted in a doorway. The primary purpose of the swing is to provide a place where the child can be exposed to unfamiliar or disliked textures. However, the mother would also like to be able to sit in the swing with her son.

Design Specifications

The swing will need to be able to support the mother’s weight safely. The child is not old enough for his weight to be significant. The swing will not be permanent, so it needs to be easily mountable and conveniently stored. A system to prevent the child from falling out of the swing is needed, but restraints are not necessary. The sensory elements should be removable to allow for greater versatility.

Background Research

When we heard that the swing would be mounted in a doorway, our first thought was of hammocks. The two attachment points provide stability while still allowing a rocking motion. Hammocks are almost completely fabric.

Platform swings are larger and typically suspended from a single point. They can either be mounted or they can be free-standing, supported by a tripod-like frame. They can be made out of a wide variety of rigid materials.

Cocoon swing, also known as sock swings, are teardrop-shaped swings with an opening in the side that are suspended from the tip of the drop. They are almost completely fabric, and usually have some type of support at the base to keep the seat around the same level as the opening.

Concept Design 1

Our first concept was to have a pair of hammocks, one for the mother and one for the child. The hammock for the child would have sensory elements on the outside. These would be accessible when he was with his mother, but not when he was inside the hammock. The hammocks would be mounted from hardware permanently attached to the doorframe.

Concept Design 2

Our second idea was a platform swing. Thick foam pads covered in cloth form walls that can protect the child when he is by himself on the swing. They can be folded down and attached to the bottom of the swing when the mother is swinging or when the swing is being stored. The sensory elements could be put on either the walls or the floor of the swing. In either case, they would be covered by a panel of fabric when not in use. The swing would be mounted from a bracket in the top of the doorframe.

Concept Design 3

Our third concept is a cocoon swing. We would place a soft platform at the bottom to increase the ease of getting the child in and out of the swing. The mother could also sit on the platform and push her child. The sensory elements would be in the inside walls of the swing, again covered by a panel when not in use. The swing would be mounted from a bracket in the top of the doorframe.

Selected Concept Design

To determine the best design, we looked at four factors: ease of cleaning, weight, how well the sensory elements would be incorporated, and how easy the swing is to mount.

As far as cleaning is concerned, the platform swing is the best, because the waterproof canvas can be wiped off easily. The hammocks and the cocoon swing are both mostly fabric, yet cannot go in a washing machine. Both would have to be spot-cleaned.

The platform swing is by far the heaviest option, since it would be made of metal and plastic. Both the cocoon swing and the hammocks are very lightweight, making them easier to move and store.

Upon further discussion with the family, we learned that the child does not like things touching his hands and feet, making the cocoon swing undesirable from a sensory point of view. The sensory elements are not very convenient in the hammocks, and there isn’t a good way for the child to interact with them. We would have to make sure that the child could reach them without bumping his head on the smaller hammock. The platform swing, on the other hand, allows him to reach everything easily, without completely surrounding him with textures.

In the end, we decided the platform swing was our best option. Although it isn’t especially light, it does the best job of meeting the child’s needs.

Decision Matrix

Overview of Selected Design

We selected the platform swing as our design. It will have a PVC platform with a soft foam cushion on top of it. The platform will be supported by an aluminum frame. Four posts will go up from the base to provide mounting points for the ropes and attachment points for the removable foam walls. A spreader bar partway up the swing will reduce the number of ropes from four to two. These ropes will meet at a swivel hook, which will be securely mounted in the doorframe with long bolts.

Describe Design Details

To reduce weight, the floor of the platform will be made of a sheet of PVC. It will be strong enough to prevent bowing while still being lightweight. An open-cell foam cushion will go on top of the platform to make it more comfortable to sit on. The cushion will have a removable cover made out of waxed canvas. The walls will be made of closed-cell foam and covered with the same canvas, but the canvas will not be removable. The padding for the corners will be secured with either glue or rivets, and the walls will be attached to the corners with zippers. The base of the walls will be attached to the frame with Velcro. The frame will be made of welded aluminum, with a small lip for the platform to sit on. We will be using moderately thick ropes for ease of handling. At the top, the swing will be secured by a swivel hook on a bracket that is screwed into the doorframe and the studs around it. To spin freely in the doorframe, the diagonal of the platform must be less than 28 inches.

Engineering Analysis 1

Based on Analysis 3

Factor of safety of just over 1 isn’t very safe. This issue and the issue of excessive deflection in the PVC base in Analysis 3 spurred the addition of cross-beam supports across the bottom of the frame to keep it sturdy.

Engineering Analysis 2

Strength, stress, and factor of safety on the upper support bar, assuming a total weight of 200 lbs.

Engineering Analysis 3

Deflection of platform

**NOTE: 2700 lbf-in. on Moment Diagram should be 1500 lbf-in.

CAD Drawings

Bill of Materials

Document Fabrication Process

All of the aluminum came in long pieces that needed to be cut to size to build the frame of the swing.¬† Once everything was cut, the pieces were taken to the formula car shop to be welded together. Once the frame was completed, the rope hooks needed to be installed. This was done by machining aluminum blocks so that they would be the anchors for the ropes to tie to through the use of eye-bolts screwed and glued to the blocks. A black PVC sheet was then cut to act as the floor of the swing. Foam sleeves were added to act as safety buffers for the sharp edges and to be the attachment points for the texture walls, each made from scratch, by way of velcro. The whole swing set will hang from an eye-bolt in the clients’ doorframe by using a clip and a swivel joint to allow the swing to rotate.

Semester

2022 Spring