CHAPTER 9

TEXAS TECH UNIVERSITYSENIOR PROJECTS DEVELOPMENT GROUP

COLLEGE OF EDUCATION AND COLLEGE OF ENGINEERINGLUBBOCK, TEXAS 79409

Principal Investigators:

Richard A. Dudek (806) 742-3543

Oliver D. Hensley (806) 742-2388

Jesse C. Jones (806) 742-3563

Tom Leamon (806) 742-3543

Donna Irons Reavis (806) 742-1958

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"Developing an Eye Tracking Device (ETD) forIndividuals with Handicaps"

An ETD Linked to a Computer Generated Communication System forStudents with Multiple Handicaps

Designers: Bobby Hudgens, Greg Hatfield, Reese Wright; First TeamKa Lam William Chio and Chow Ming Wong; Second TeamCoordinator for the Disabled Students: Don Foreman

Supervising Professors: Dr. Michael Parten and Mr. Eddie ArrantDepartment of Electrical Engineering

Dr. Oliver D. Hensley and Dr. Donna ReavisCollege of EducationTexas Tech UniversityLubbock, Texas 79409

INTRODUCTIONThe purpose of designing an Eye-

Tracking Device (ETD) was to develop acommunication device for Terry, a 19-year-old teenager who has profound scoliosis andsevere spasticity. Terry has never beenable to communicate with those around him.Don Foreman, Terry's teacher, was convincedthat although Terry had an uncontrollablebody, he had a bright mind and a wonderfulsense of humor. The difficulty was thatthe messages from the brain became garbledand uncontrolled before they could beuttered. Don was the only one who believedhe was in touch with Terry's mind. Hecould communicate very crudely by a simplesystem of Terry's winking and Don's sayingoptions until they hit on what Terrythought. The problem for the Senior DesignTeam was to find a way of getting Terry'simprisoned thoughts out to others--something that had not been accomplished in19 years of internment in a state school.After two years of concentratedinterdisciplinary research, the SeniorProjects Team did free Terry's thoughts.

SUMMARY OF IMPACTThe ETD was a critical technological

component in the Svnthetic SveechCommunications System built for Terry. Thetechnology created by the Senior ProjectsTeam opens up a whole new area of basicresearch related to communicating with theseverely and profoundly disabled child.

This article will mention only a few ofmany ancillary benefits resulting from theSenior Projects Team's investigation.First, there is the improvement in Terryfrom the Hawthorne effect. People outsidethe school paid attention to him, asked hisopinion. That improved his mental outlook.

A small amount of seed money from theNSF Senior Projects started this long-termproject and convinced the TexasRehabilitation Commission, the BallengerSchool, and Texas Tech University to pooltheir financial and human resources todevelop a system to be used specifically byTerry to benefit his life. Thiscommunication device allowed Terry tocommunicate with the outside world--toexpress his needs, to show his feelings,and to learn.

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TECHNICAL DESCRIPTIONThe cornea1 reflection method of eye-

tracking uses the subject's cornea toreflect light from a stationary lightsource. The light source will cause abright spot to appear on the cornea, andthe bright spot will stay at the sameposition when the subject moves his eyes;thus, relatively speaking, the brightspot moves whereas the eyes do not. Thisis an important characteristic indetermining the eye focus. One advantageof the cornea1 reflection method is thatthe bright spot shown on the pupil willremain in the same position on the corneaeven though the head moves (Young &Sheena, p. 414). This is the main reasonfor Research Group #l deciding to use thecornea1 reflection method to track theeye movement.

Bobby Hudgens determined that VOCAIDwith certain modifications was the voicesynthesizer suitable for Terry. It canpronounce phrases such as "I WOULD LIKETO USE THE BATHROOMtl or "1 AM IN PAIN".It can also pronounce the alphabet andthe numbers. Although the vocabulary forVOCAID is limited, it is extremely usefulfor severely handicapped people.

Figure I--Block Diagram of theProject represents the major componentsin the project. The video camera and itspowerful zoom lens are responsible forobtaining the analog video signal fromthe eye. Then the PC-EYE digitizes the

picture so that the computer can storePC-EYE digital data in its memory buffer.After data storage, the computer presentsa menu which allows Terry to select byeye gaze the Vocaid graphics desired,and the computer will analyze the PC-EYEpicture to find the gaze-point. Afterthe gaze point is determined, thecomputer sends out proper data to theinterface circuit which serves as abridge between the computer and theVocaid, so that the desired button of theVocaid voice synthesizer can beactivated, thus allowing Terry to talk.

The Synthetic Speech CommunicationsSystem cost in excess of $2,000 formaterials and supplies. The equipmentcosts were shared among the NSF, TexasTech University, and Texas RehabilitationCommission.

More than 400 student hours werespent in designing, fabricating andtesting the system. Now that weunderstand the parameters of the System,it can be modified for other severely andprofoundly handicapped children.

Preliminary data from Terry's casestudy indicate that these children aremore intelligent than professionalassessments indicate. Texas TechUniversity intends to investigate thelearning abilities of similar children.

SoftwareControl

PC-EYEImage

Digitizer

Fig. 1 Block Diagram of the Project

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18Developing a Prototype of a Multiposition-Low-Base Wheelchairfor the ClassroomI

An Innovative Wheelchair for Children with Severe Cerebral Palsy

Designer: Ross McDonaldTeacher of the Disabled: Ms. Lynn VitatoeSupervising Professors: Mr. Jesse Jones

Department of Mechanical EngineeringDr. Oliver D. Hensley and Dr. Donna Reavis

Callege of EducationTexas Tech UniversityLubbock, Texas 79409

INTRODUCTIONAMultiposition-Low-Base Wheelchair for

the classroom was designed and constructedfor a child in the first grade of a regularpublic school. Jay, the recipient of thiscustomized wheelchair, is a veryintelligent and socially well-adjusted six-year-old with severe cerebral palsy withspastic guadriplegia. The disease andconfinement to a conventional wheelchairhave greatly retarded the movement andendurance of a youngster who is capable ofcompeting and excelling scholastically withhis classmates. Unfortunately, his spasticmovements leave him without control of thelower hip area. His teacher and parentsasked for a wheelchair that would allow Jayto sit at first grade tables, change hisposition as the furniture demanded andallow Jay to control the chair movement.Jay's teacher thought that themultipositioned chair would alleviate thephysical fatigue experienced by Jay aftertwo hours in a conventional wheelchair.

SUMMARY OF IMPACTJay thrived on being part of an

experimental project. He discussed thedesign and enjoyed working with Ross andMs. Vitatoe on the testing of theMultiposition-Low-Base Wheelchair.

Unfortunately, all project devices donot work forever. The Multiposition-Low-Base Wheelchair is a case in point. Theadjustable height screw failed after ashort service, leaving the chair functionsbelow expectations. This is a problem forthe University because Senior Projectsstudents graduate and leave Lubbock and ourdepartments do not make follow-up repaircalls. The parents and Jay are graciousand will wait for another phase of SeniorProjects students who might want to improveon the design. The PI's have proposed thatpublic school maintenance workers repairand maintain assistive devices or that theparents do the repairs. Unfortunately,when we design and fabricate it and give itaway, we still seem to own it when it needss-ice.

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TECHNICAL DESCRIPTIONMr. McDonald tried two design concepts

which proved to be inappropriate. Thethird and final design concept which wasadopted was a lift mechanism that isavailable on the market. Because thedevice was already constructed, time wassaved by purchasing the lift mechanismrather than constructing one. The liftmechanism consists of a lead screw attachedto a reversible DC motor which is geareddown to enable the wheelchair seat to beraised up and down at a velocity ofapproximately 0.75 inches per second. Thedevice is compact and can be operated bythe wheelchair user. The lift mechanismallows a height differential of 6.25 inchesfor the chair. Additionally, because thelead screw is enclosed in a sleeve, thedevice is deemed to be quite safe.

After selection of the lift mechanism,the next step was the design of a completeapparatus compatible with the liftmechanism. The final design is shown inFigures 3 and 4 for side and front views,respectively. A design criterion for theconstruction of the wheelchair was that the

device be able to grow with the child. Tosatisfy this requirement, the foot rests aswell as initial height of the seat areadjustable to compensate for the child'sgrowing body. An additional designconstraint was that the wheelchair arms beremovable to enable the wheelchair to beplaced under a narrow or otherwiseconstricting desk. This goal was achieved.

The wheelchair is compact and designedto be pushed from the rear. The liftmechanism is controlled by the child so asto give him some autonomy. Thus, the childcan adjust the seat height of the chair tohis own satisfaction. The lift mechanismis powered by a compact rechargeable DCbattery that fits under the seat of theapparatus. A bottom-heavy design wasconstructed to lessen the chance that thedevice could inadvertently tip over. Thisbottom-heavy design was constructed byusing angle iron (l-inch flange) for thebase frame.

The Multiposition-Low-Base Wheelchairdevelopment costs were $375 and 87 hours ofstudent time.

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"Automated Packaging Process"The Development of an Automated Egg Sorting Machine

for Mentally and Physically Disabled Students

Designers: Donna DiMarco, Boris Dmitrijev, Melvyn Fernandezand David West

Coordinator for the Disabled Students: Mr. Jack KirkpatrickSupervising Professors: Mr. J. C. Jones and Dr. Oliver HensleyDepartment of Mechanical Engineering and College of Education

Texas Tech UniversityLubbock, Texas 79409

INTRODUCTIONThis Senior Project addresses the

difficult problem of designing,fabricating, and testing an automated eggsorting machine that could be operated byphysically and mentally handicappedstudents. Commercially available equipmentwas not suitable as conventional machinesare too hazardous to have in a shelteredworkshop and they do not have the adaptivetechnology needed by handicapped persons.Consequently, the Senior Projects Teamdesigned a system that incorporated everyconceivable safety device and includedinnovative devices for performing the workwhile assuring maximum safety and access byhandicapped students.

The Lubbock State School is a schoolfor the mentally and physicallyhandicapped. Some of these students earna small income by stuffing miniature toysin plastic eggs. There are nine differenttoys which are stuffed into the eggs afterwhich the eggs are stockpiled andsubsequently packaged for delivery. Thesestudents can stuff approximately 200,000eggs per week. The Lubbock State Schoolhad a production problem with the packaging

of the toy eggs. The eggs are hand sortedand packed into boxes containing 250 eggs.Each of these boxes required a differentmixture of toys according to individualcontracts. This required individualsorting of the eggs for packaging. Only80,000 eggs could be packaged per week. Ahuge backlog of stuffed but unpackaged eggsexisted. This bottleneck prevented theschool from placing more students in theworkshop.

SUMMARY OF IMPACTThis project helped the Lubbock State

School automate the packaging process.Bins to hold the eggs were designed andfabricated. An Apple II computer was usedto control the output of eggs from each binwith the use of a computer interfacesystem. BY automating the packagingprocess with a computer interface system,the students at the State School becameinvolved with the process. The AutomatedEgg Processing System eliminated the verylarge backlog of unpackaged eggs andpermitted the School Coordinator to usemore students. The Automated EggProcessing System worked beyond theexpectations of the Coordinator of theworkshop.

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TECHNICAL DESCRIPTIONThe Automated Egg Sorting System

consists of storage bins, rotary disks,funnels and gravity chutes. The storagebins are capable of holding approximately1500 eggs each. The 8-slot rotary disksturning at 6 RPM are able to deliverapproximately 48 eggs per minute per bin.The funnel design ensures the delivery ofonly one egg at a time. The gravitychutes deliver the eggs from the bins toa central location without clogging.

The electrical system consists of acomputer, related software, associatedcircuitry, photocells and electricmotors. The computer used is apreviously owned, inexpensive Apple II.The software is a program written inBASIC language. The associated circuitryincludes transistors, 2 multiplexers and2 demultiplexers connected to a 5- and12-volt power supply. The photocellsused are prefabricated 12-volt opticaleyes. The motors are IlO-volt, 6-RPMDayton Electric Motors.

After fabrication and assembly ofthe above components, the system wasevaluated for use in a sheltered workshopenvironment. Custom-designed adaptivedevices for specific handicapped personswere designed, installed, and tested foruse by particular persons. Test runsindicated that the packaging capabilityof the system was approximately 30 boxesof eggs per hour. When calculated on aweekly basis, 300,000 eggs per week can

be packaged. The automated packagingprocess thus represents a 250 percentincrease in productivity over theprevious manual process.

At present, the Lubbock State Schoolis packaging nine different toys, thusnine storage bins were required. Each2x2x3 foot bin was constructed of #28gage sheet metal (see Figure 1). The 12cubic foot volume allows each bin to holdapproximately 1500 eggs. The eggs aredelivered to a rotary disk feeder by anoff-centered funnel (see Figure 2). Thefunnel is off-centered to allow only oneegg to drop from the bin at a time. Thefeeder consists of an 18-inch diameterdisk driven by an electric motor. Eachdisk has eight 2.5-inch diameter slotsmachined in its face. These slots arecentered on a 15.5-inch diameter circle.An egg drops into the slot and is rotatedaround until it becomes aligned with adelivery chute. The delivery chutesystem consists of folded #28 gage sheetmetal. The chute system is an opentrough. It is welded to the supportstructure of the bins. The chuteconverges to a convenient centrallocation where the boxes are filled witheggs. The support structure of the binsis made of angle iron.

The final cost of the operationalsystem was approximately $2,500 and over384 hours of Senior Projects students'time and an additional 300 man hours fromtechnicians and machinists employed bythe Lubbock State School and theBiocybernetics Laboratory of Texas TechUniversity.

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@'Automated Gravel Bagging System"Creating a Sheltered Workshop Laboratory that Provides

Experience and Adaptive Equipment Needed by Handicapped Students

Designers: John Julian, Victor Deutsch, John DiederichCoordinator for the Disabled Students: Mr. Jack KirkpatrickSupervising Professors: Mr. Jesse Jones and Dr. Atila Ertas

Department of Mechanical EngineeringTexas Tech University

Lubbock, Texas

INTRODUCTIONThe purpose of the Automated Gravel

Bagging System (AGBS) was to design andconstruct a sheltered-workshop laboratorythat could be controlled by handicappedclients at the Lubbock State School.

Several of the bagging system'scomponents were commercially available suchas the vertical elevator, the sewingmechanism, the sump pump, and the linearactuator. Other components such as theweigher and gate mechanism were designedand fabricated by the project team. Allcomponents were either modified or designedto accommodate the particular client'sdisabilities.

Primary control of the system isachieved through the use of a computerterminal operated by a physicallyhandicapped client. Mentally handicappedclients operate the system's on-linefunctions. Several customized adaptivedevices were designed that enabled personswith particular disabilities to work in thesystem.

SUMMARY OF IMPACTThe Automated Gravel Bagging System

presents many benefits to the clients. Thehandicapped students run the system fromstart to finish. Two primary benefitsoccur. The disabled student gainssatisfaction, pride, and money every timehe is successful in bagging a load of

79409-1021

gravel. Success breeds success: therefore,the handicapped students are learning thatthey can perform most jobs if they willwork with designers in modifying equipmentthat will interface with standard systems.The effects of this work success reach intothe students' home life as well. Thesheltered-workshop laboratory provides thefirst step toward work in the real world.

The students have learned valuableskills and they demonstrate they can makea valuable contribution to the productionindustry which is external to the LubbockState School. Students can go out into theworld, take a job at an assembly plant, andmake $3.50 to $5.00 an hour. This is thegoal of many of the clients at the StateSchool.

Without the cooperation of the SeniorProjects staff, the Texas RehabilitationCommission, Lubbock State School staff, andthe dedicated work of the Project Team,this laboratory and AGBS would not havebeen designed, built and tested.

The laboratory and system are in useevery workday with students eagerlyawaiting their turn to run the system.

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TECHNICAL DESCRIPTIONThe Automated Gravel Bagging System

starts by using a vertical elevator to liftthe gravel from a gravel bin located belowground to the hopper. The system thenemploys a gravel weigher mechanism toensure that a uniform volume of gravel isdelivered to the bags. Once the bags arefilled, they are closed with a sewingmechanism and transported to a loading areaby a non-driven conveyor. Computer controlwas incorporated into the system to supplythe severely physically handicapped with ameans of controlling various aspects of theoperation. These control operations aresimple but challenging, and they present nodanger to the students from the movingmachinery. The client's safety was of theutmost importance in the design of thissystem.Gravel Pit

Gravel that is transported to theschool will be dumped directly into agravel pit. The pit's walls are designedto withstand the forces exerted by sevenyards of gravel. Sloping the bottom of thepit at a 45-degree angle keeps the gravelflowing steadily toward the pit's lowerdoor. This angle exceeds the concretesurfaces angle of repose, 37.5, which wasfound through experimentation.Gate Mechanism

The main purpose of the gate mechanismis to regulate the flow of gravel to thevertical elevator. The gate consists of avertical door and vertical runnino tracks.The running track is constructed- of 1018Hot Rolled steel. The bearings used in the

running tracks are 0.75-inch O.D. with a0.25-inch I.D. The bearings provide asmooth and easy vertical movement for thesliding door. The sliding door isconstructed of 0.3125-inch-thick, 1010 HotRolled steel. The door is powered by alinear actuator that can raise the door upto 12 inches.Linear Actuator

The force required to open and closethe door is supplied by a Dayton linearactuator. The maximum extended distanceand applied load is 12 inches and 300pounds. This AC model comes with fullyadjustable limit switches, which can be setto stop the motion of the lifting screw atany desired point of travel in eitherdirection. This characteristic gives thesystem the required variable gravel flowand fast gravel flow shut-off.Vertical Bucket Elevator

Transferring the gravel from the gravelpit to the surge bin is accomplished byusing a vertical bucket elevator. Theelevator's 220 CFM capacity more than meetsthe production requirement of 300 bags aday.

A symbol of success for most projectsis completion on time and under budget.With a great deal of pride, the members ofthe gravel bagging project proclaim thattheir project accomplished both. Theexpenses incurred through completion ofthis project were less than the $5,000estimated for the project which were mostlypaid for by the Lubbock State School. Lessthan $500 was from the Senior ProjectsFund.

CHEST CONTROLLED SEWING MACHINES

Designer - Zane D. Curry1Supervisor - Tom B. Leamon2, Ph.D.

Merchandising, Environmental Design and Consumer Economics1Industrial Engineering*Texas Tech UniversityLubbock, TX 79409

Introduction

Commercially available machinesused in the stitching trade such assewing machines, serging machines, etc.are normally controlled by a treadleoperation, which changes sewing speedby acting through a series ofmechanical linkages to the clutch onthe sewing machine motor. In addition,the presser-foot (the device whichlocates the fabric in relationship tothe needle or cutters) is normally footoperated. In practical terms, suchmachinery is not accessible to thewheelchair disabled and cannot becontrolled by those who do not have useof their lower limbs. A studentenrolled in the College of HomeEconomics, who intends majoring infashion design is confined to a wheelchair due to a spinal cord injury,Functionally, she has no control of herlower limbs. The program in which sheis enrolled has upwards of 18 hours ofcourse work which require the use ofsewing and allied machines which areoperated with a treadle and with footoperation of the machine presser-foot.Without a design solution it would havebeen impossible for her to graduatefrom her chosen program.

Impact Summary

The occupations associated withsewing machines appear, on the onehand, to be highly compatible with thelack of mobility of paraplegics, inthat they normally involve a fixed workstation and can be operated from asitting position. Such opportunitiesfor wheelchair paraplegics are entirelyvitiated by their need to gain manualaccess to the stitching area and by theneed to use foot controls. It appearsthat both in the individual case underinvestigation and in a much widersample of the disabled population, asolution to this problem would providewide employment opportunities. Thus, a

requirement for extendibility orgeneralizability of possible solutionswas added to this design project.Namely, a solution was sought whichcould be reproduced on a variety ofmachines associated with stitchingoperations.

Technical Description

A detailed task analysis wasperformed, based on direct observationand analysis of video tapes of non-handicapped and the handicapped subjectattempting to perform the operations.

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The clear need to relocate thecontrol location suggestedelectromechanical devices. However,the need for rapidly changing andhighly consistent forces for use overextended periods, indicated that suchsolutions were likely to be expensiveand had the potential for beingunreliable. Consequently, themechanical linkages that link treadleand the clutch on the drive motor werecarefully examined and a solution basedupon additional mechanical linkages wasdesigned and a prototype built.

The stitching operation largelyprecludes the use of any handcontroller, for precise positioning ofthe work piece in relationship to theneedle or serging blade is an absoluterequirement of the task. Consequently,alternative effector mechanisms wereexamined. Elbow and shoulder positionswill produce adverse interactions withthe precise control requirements of thehands, and an experimentalconfiguration was developed, using achest plate operating approximately inthe region of the sternum. Thepotential for causing musculoskeletalstresses by the use of postural musclesto control this mechanism wasconsidered, together with potentiallylow level of precision available fromthe operation of the control by thesemuscles.

In preliminary trials, however,the subject did not experience undopostural stress and very rapidlyappeared to be able to obtain the finepositional control required. Severaltrials supported the suitability ofthis design solution.

A further question was raised;what the comparison of theperformi:ce of the disabled with thatof non-disabled operators. That is,would the design constrain the disabledsubject into an inherently inferiorperformance pattern or could she beexpected to reach full performancestandards. An experiment wasdeveloped, and is currently beingcarried out, which compares theperformance of able bodied subjects,both on traditional treadle control andon the chest control. Preliminaryresults showed that the chest controlproduces results at least equal to thetreadle and there is evidence tosuggest that the former is a preferredcontrol, even for the able bodiedsubjects. The performance measuresutilized, involved both the accuracy ofline following and the time to completethe operations.

Subject to further experimentationand confirmation of these pilotstudies, it appears that the deviceenables the disabled to operate any oneof a series of machines by providingboth access to and control of themachine. It appears to provide thepotential for achieving equalperformance with the able bodied usingconventional controls.

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"The Development of Assistive Devices for Deformed Hands"Designing Devices that Allow Handicapped Children

to Independently Operate Classroom Equipment

Designers: Ames Hwang, Valerie Matthews, and David CroweCoordinator for the Disabled: Mr. Jack Kirkpatrick

Supervising Professor: Dr. W. B. JonesDepartment of Mechanical Engineering

Texas Tech UniversityLubbock, Texas 79409

INTRODUCTIONThe manipulation of common machine

tools and classroom furniture is veryimportant in the Senior Projects' strategyfor assisting handicapped students tointegrate themselves into the mainstream ofschool and life. Some children have suchsevere deformities of the hands that theycannot function in an ordinary classroom.However, if they are given adaptive devicesmolded to their hand configurations, theycan perform most operations in an ordinaryclass or in our Sheltered-WorkshopLaboratories.

This Senior Project produced twoprototype devices for use as assistivedevices for deformed hands. The firstdevice, a pair of modified pliers,increases a handicapped student's strengthby about four times. The new head designis used to grip different shaped objects.It can turn knobs, pick up small objects,and open push-button seat belts. Thehandles are custom designed to fit theshape of the hand, easing the stress on thefingers of the handicapped student. Thesecond device is a strap wrench primarilydesigned to open jars or door knobs. Acontinuous belt is attached to the one-piece handle. The belt is adjustable tovarious sizes of jars. The handle is alsoformed to fit the user's hand. Smallforces are needed to operate the tools andthe stresses incurred are relatively low.Both designs are simple and suitable for

SUMMARY OF IMPACTFor a Senior Projects program to

function efficiently requires a great dealof coordination among the handicappedstudents, the coordinators of the disabled,university professors and students who domost of the design, fabrication, andtesting of various orthotic and assistivedevices. All of our Senior Projectsdevices have grown out of needs ofhandicapped individuals. Many of thedevices can be constructed only on aresearch university campus, such as TexasTech University, where there is eleganteducation, sophisticated science andadvanced technology.

The modification of Channellock Pliersand the development of a strap wrenchostensibly may seem a trivial and low-priority engineering and education problem.Not much basic research here. But, thereis a great deal of production research thathas significance for production of custom-desianed tools for the handicapped. Mostimportantly, for our handicapped studentsto function in the Sheltered-WorkshopLaboratories and in cooperative employment,they must have adaptive devices that theycan use. These devices are used byhandicapped students in school and later incooperative employment.

injec:tion molding.

TECHNICAL DESCRIPTIONThe objective of this Senior Project

was to modify two basic hand tools that canbe used easily and effectively byhandicapped school children to perform avariety of tasks. The two tools that havebeen selected are slip-joint pliers and astrap wrench. These tools will aid in themotions of pinching or grasping andtwisting. The design of the tools willincrease the strength of the child.Torque and Leveraae

A handicapped child can also increasehis or her strength through leverage. Theforce required to hold an object (Fl) canbe achieved by applying a smaller force(F2) at a distance and creating opposingtorques. The necessary force is decreasedby a factor of x1/x2.Results: Tool 1 - Pliers

The first tool is a modified pair ofnine and one-half inch Channellock pliers.The purpose of this tool is to aid ahandicapped child in grasping and/orturning small objects such as television orradio knobs, Another main function of thepliers is to help in unfastening the push-button type of seat belts.

This problem was approached first bystudying a pair of commercially availableChannellock pliers. A silicon rubber moldwas made of the steel pliers, then an epoxymodel was cast from the mold. Results ofphotoelastic analysis revealed that thegreatest stress occurred at the narrowsection of the upper handle when no torquewas applied. This stress was nearly twiceas great as the stress in the narrowsection of the lower handle. Stress

F,xl =F2x2

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concentrations also occurred at the cornersof the head of the pliers. However, thestress lines were uniform along the handlesindicating no stress concentrations. Adownward torque applied to the pliersshowed increasing stresses in the upperhandle. Conversely, an upward torqueincreased the stresses in the lower handle.Tool 2 - Strap Wrench

The second assistive tool is a strapwrench. The purpose of this tool is tohelp a child open jars, knobs, or anythingthat requires twisting. Unlike themodified pliers, the strap wrench is builtentirely from scratch using new designs.

The frame was machined out of five-eighths-inch sheet aluminum. Two curveswere cut into the head to accommodate bothsmall and large diameters. An la-inch,toothed polyurethane sewing machine beltwas attached to the other end of the head.A notch was cut out of the aluminum nearthe end of the handle for the belt to gothrough for adjustment. A top plate wasattached to the head of the tool to aid inplacement and use of the tool. The handleof the strap wrench was dipped into themelted thermoplastic and shaped to thehand. The tool was designed to be pushedaway from the body. The near side of thehandle was cup-shaped to fit theeccentricities of the palm of the hand.

Texas Tech University's costs fortooling and production equipment wereconsiderable. But, the actual allowablecosts to this project were less than $200and 56 hours of Senior Projects students'time.

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"Development of a Therapeutic Crawler"The Design and Fabrication of a Therapeutic Crawler

for Students with Multiple Handicaps

Designers: Jim Bielstein,Nat Phillips,

Mike Etheridge, Lance Free,Anita Green and Alan Tribble

Supervising Professors: Mr. Jesse C. JonesDepartment of Mechanical Engineering

Dr. Oliver D. Hensley and Dr. Donna ReavisCollege of EducationTexas Tech UniversityLubbock, Texas 79409

INTRODUCTIONPam is a physically and mentally

handicapped twelve-year-old child. She isblind and non-ambulatory which restrictsher to a wheelchair or bed. Pam's physicallimitations are due to her slightly curvedspine, one leg being shorter than theother, and below average motor skills. Sheexhibits poor posture and balance. She isunable to bear much weight on her arms orlegs. Pam has little active movement andcannot independently attain positions;however, she does respond to physicaltherapy. She has normal muscular tone andadequate head and trunk control whensitting in a wheelchair. As a result ofher present therapy, she can now stay in afour-point position (on hands and knees)for a short period of time.

The physical goals for Pam aremaintenance of a four-point position for anextended period of time and an increase inoverall strength and balance. Her long-range physical goal is to increase hermobility. Also incorporated into hershort- and long-range goals is thedevelopment of independence in self-helpskills.

A crawler that was previously used intherapy was not adjustable, and in someways movement was rough and slow. The newcrawler is adjustable and can be adapted toimprove the exercise of specific limbs.

SUMMARY OF IMPACTThe crawler was designed and fabricated

to specifications as required by thetherapist for Pam,for this project.

the handicapped clientThis therapeutic aid

device will give Pam a sense ofindependence and mobility, providinganother way to explore her environment.Pam and other children with similarhandicaps will use the crawler forimproving their self confidence andexploring their environment.

By combining the support structure andleg assembly, harness assembly, and wheelassembly, a more adaptable and maneuverablecrawler has been designed. This designsignificantly expands the client's rate ofprogress by adding to the tools of thetherapist. The crawler, in the earlystages of the client's therapy, aids insupporting her body in aposition while,

four-pointafterwards, helping to

develop balance and muscle control neededto begin independent crawling.

TECHNICAL DESCRIPTIONTaking into account the client's

physical limitations and planned therapy,it was decided that she needed a device toaid in her therapy by improving balance andmuscle control. The device chosen, basedon the client's limitations, was a four-point position crawler. The crawler iscomposed of four multi-adjustable legs andsupporting structure, a harness assembly,and a wheel assembly.

The crawler's legs span above theclient and then arc down to create asupporting structure for the harnessassembly and client. The legs andsupporting structure are made of 1 5/16-and l-inch steel tubing. The differentpipe sizes are to allow enough of aclearance to produce a sliding fit, thusallowing for adjustability in length,width, and height. This adjustabilityaccommodates the growth of the client andalso the possibility of the crawler beingused by another handicapped person. Thecrawler was designed with safety featuressuch as a safety belt to hold the client inplace, and legs that are designed wide

enough to keep the wheels out of reach ofthe child. The crawler is adjustable inheight from 10 to 13 inches. The wheelsare 31 inches apart from side to side and23 inches apart from front to back. Themaximum yield strength in the legs is 54ksi allowing a maximum load of 90 pounds.

The harness assembly maximizes comfortand support, thus potentially increasingthe time spent in the crawler by theclient. The harness consists of a 3/S-inchsteel plate fitted with a cushion andsupported by straps attached to thesupporting structure. These straps areadjustable using buckles and clasps.

The wheel assembly includes roller-ballcaster wheels as opposed to thin, flatcaster wheels. Roller-ball caster wheelsfacilitate maneuverability on flatsurfaces, indoors as well as outdoors. Thewheels also have covers around them toprevent the client from rolling the crawlerover her hands while crawling.

The Senior Projects' student time spenton design, fabrication and testing was 102hours. Less than $200 was spent onmaterials and supplies.

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Top Half Symetrical to botton Half

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