Customization of Educational Resources for Harris-Hillman

Special Education School

Robert Connor

Proposed Problem

• An adjustable tray with side pieces (wings) (to keep arms inside). The tray needs to adjust height and angle--to fit feeder seat.

Background

• Special Education students are Special

• Harris-Hillman contains the students that are too handicapped for inclusion

• Irene Lowe’s class contains the most handicapped of all Harris-Hillman students

References: Duran, Elva. Teaching the Moderately and Severely Handicapped Student and Autistic Adolescent. Charles C. Thomas:1988

Berdine, W; Blackhurst. An Introduction to Special Education. New York: 1985.

Project Breakdown

P ro jec t # 1 aB u ild res tra in t d evice

P ro jec t # 1 bB u ild ed u ca tion a l tray

C u s tom iza tion o f E d u ca tion a l R esou rces

Subject Anthropometrics

• Sitting height 60 cm• Weight 26.3kg(58lb)• vertical CG at 30%

sitting height (~18cm) from base

• horizontal CG 20cm from seat back

• Muscle Force exerted in Frontal plane: 20lb

• Reference– Roche, Alex and Robert

Malina. Manual of Physical Status and Performance in Childhood. Vol. 1A. Plenum Press. New York: 1983.

• Muscle Force exerted in the Sagital Plane: 25 lb.

Frontal Plane

Sagital Plane

Calculations and Testing

• Restraint Device– Device withstands

calculated extremes in the changes in the CG and the estimated Muscle Force Exertions

– Tested initially by weight placement until failure

– Tested in classroom with success

• Tray table – Calculations show that

a working load of 45lb.

– Tested by weight placement

Design Specifications

• Strength Considerations– 125 cm^2 of touch

fastener minimum

– 187 cm^2 Incorporated in Design

• Safety Factor – 1.5

Threshold (Normal) Strength v. Area

y = 2000x - 50

50

0 0.01 0.02 0.03

Area Touch Fasterners (m^2)

Th

res

ho

ld

Str

en

gth

(lb

)

Sheer Strength v. Area

y = 2000x - 50

20

40

60

0 0.01 0.02 0.03

Area Touch Fasterners (m^2)

Th

res

ho

ld

Str

en

gth

(lb

)

Safety Considerations

Economic Analysis

• Market Analysis– Customers

• tall, severely-handicapped individuals with little muscle control

• 10,000 students nationwide

– Life cycle• lasts about two years

depending of frequency of use

• Cost/Benefit– Development Costs

• 1 student@$10/hour for 60 hours

• Materials $20

– Benefit Analysis• Safer experience• 15 minutes of Instructor’s

time per day (Correcting a child for one minute every fifteen minutes that the chair is in use. )

Questions and Suggestions