Crawler for Child with G-tube F12

Abstract

Project goal is to design and assemble a crawler assist for a 12 month old with special needs. Because the child has a gastronomy tube (g-tube), design specs require that the device not apply pressure on the abdominal area, and also be able to support a pump and medication/fluid bags that the child is dependant on at all times --Rsescue21 (talk) 12:08, 30 September 2012 (CDT)

Team members

Jeremiah Bishop, Robbie Brown, Zach Denson, Becky Escue, and Corbin Paul

Introduction

(family meeting notes here)

Design Specifications

The crawler is to help the child develop strength and allow her to mimic crawling motion until able to do so on her own. The crawler must be able to support weight of child, pump and fluid bags. It will be used on hardwood floors and must be able to fit through doorways. Parents' preference is that the suspended harness have 360 degree motion. The anticipated need for the device is up to 1 year, so harness will be adjustable to account for weight gain and decreased dependency. Harness must avoid applying pressure to lower rib cage where g-tube is located. Device must be lightweight with high quality castors so that the child can be as mobile as possible. --Rsescue21 (talk) 12:08, 30 September 2012 (CDT)

Conceptual Design

Design Concept 1

Design Concept 2

Design Concept 3

Concept Analsyis

	Design 1	Design 2	Design 3
Safety	5	5	5
Freedom of Movement	3	3	5
Ease of Manufacturing	4	5	3
Cost	3	4	3
Portability	1	4	4
Consumer Satisfaction	2	2	5
Total	18	23	25

Design Analysis

Bearing/Shaft Analysis

Leg Analysis

Displacement
Factor of Safety
Stress

Centerpiece Analysis

Displacement
Factor of Safety
Stress

CAD Drawings

Crawler Assembly

Exploded View of Connection

Caster

Centerpiece

Leg Dimensions

Shaft Dimentions

Casters

Swivel caster, housing made of Polyamide, with blind hole for furniture fittings. Wheel center made of Polypropylene, Tread: TENTEprene (thermoplastic rubber), grey non-marking, plain bearing.

http://www.tente.us/US/cat220/an3917_furniture_casters.html

Harness Pattern

This is the basic structure of the harness that Isabella will wear when using the crawler. The bodice is short enough to avoid pressure on the g-tube. The three-point design will support her upper as well as lower body as she builds strength while learning to crawl. Instead of a single strap suspending Isabella from the crawler, we think extending the three-point design up to the mounting plate will increase ease of mobility.

Visuals

Crawler Paint Scheme

Bill of Materials

Quantity	Item	Price
3	T-Handle Quick Release Pins 3/16" Diam. 1 1/2" length	$18.64
1	6"x6"x 1 1/2" 6061 Aluminum Block	$55.98
3	Cat Casters	Donated (Tente Casters)
1	Steel Ball Bearing 2" O.D. 1" I.D. 1/2" Width	$10.61
1	1/4"x 12"x12" Aluminum Sheet	$20.11 ea
24 ft	1" O.D. .065" Wall Thickness Aluminum Tubing	$44.16
	Total	$186.78