chapter 20 university of south alabama - national …nsf-pad.bme.uconn.edu/1990/chapter20.pdf ·...

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CHAPTER 20

UNIVERSITY OF SOUTH ALABAMAMechanical Engineering Department

Mobile, Alabama 36688

Principal Investigator:

CeciZ 2%. Ramage (205) 460-6168

305

306 NSF 1990 Engineering Senior Design Projects to Aid the Disabled

A Child’s Recreational Alternative to a PoweredWheelchair

Designers: Virginia Byrd, James Cunard, Ray Kesterson, Lynda Lebel, GeojfPainterDisabled Coordinators: Robert Perry, Rehabilitation Engineer

Vocational Rehabilitation ServicesPatti Fassbender, Physical Therapist

Rhonda Boles, Occupational TherapistSupervising Professor: Dr. Cecil H. Ramage

Department of Mechanical EngineeringUniversity of Sou th Alabama

Mobile, AL 36688

INTRODUCTIONTo allow for outdoor activity a three year oldcerebral palsy client a recreational alternative for apowered wheelchair was requested. The availablepowered riding toys for handicapped children don o t m e e t t h e c l i e n t ’s n e e d s . T h e r e f o r e , i ncooperation with the United Cerebral Palsy (UCP)Center of Mobile, Alabama, a commerciallyavailable electric-powered toy jeep has beenmodified. The seat in the jeep has been replacedwith a base to attach therapeutic posture seating.The steering wheel and foot pedal have beenreplaced with a gated joystick and electronic controlsystem.

A motor and linkage to turn the front wheels havealso been added to compensate for removal of thesteering wheel. Other modifications include asecond joystick that allows the supervising adult tooverride control of the car if necessary.

SUMMARY OF IMPACTWhile this vehicle was constructed to meet thespecific needs of the client, the design conceptscould easily be adapted to a range of children. Forexample, the seat attachment base allows theattending therapist to prescribe the best postureseating for each child. The UCP Center staff hasexpressed an interest in modifying jeeps for thecenter and other young clients. The adaptedelectric-powered toy jeep allows the client tointeract with the outdoor world.

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TECHNICAL DESCRIPTIONAn outdoor recreational alternative for a poweredwheelchair has been constructed in cooperationwith the United Cerebral Palsy Center of Mobile,Alabama. T h e m a i n c o m p o n e n t s o f t h emodification of the Power Wheels toy jeep areoutlined below

SeatingAn attachment base for therapeutic posture seatinghas replaced the stock car seat. This base isconstructed on 2x8 lumber and 1” diameter tubing.The plastic car body is sandwiched between thecross boards so that the plastic is not subjected topoint loading. While this attachment base was builtespecially for the client’s posture seat, this designc o u l d e a s i l y b e a d a p t e d f o r o t h e r s e a t i n gconfigurations.

Other SupportA swing-away tray was included for joystick armsupport. Foot support was provided by a multi-layer wooden platform added to the floor of the car.Layers of the platform may later be removed whenincreased leg room is needed. The safety harnesssupplied with the posture seating will be used forrestraint.

Joystick controlA gated joystick was located for right-dominanthand control. The joystick returns to neutral whenreleased and power to the motors is disconnected.A second joystick has been included to allow thesupervising adult to override control of the carwhen necessary. Depressing the fire button on thesecond joystick transfers control of the car to thesupervisor’s joystick until the fire button is released.The fire button of this auxiliary joystick energizes afour pole double throw (4PDT) relay locatedbetween the four output leads of the main joystickand the rest of the control circuit.

Battery CircuitThe car came equipped with two 6 volt batteries.The batteries were wired in parallel to the motorsand in series using a diode to the relays.

Drive Motor CircuitA small DC motor and gearbox assembly is at eachof the rear tires. Each drive motor is wired to itsbattery and the joystick through two single poledouble throw (SPDT) relays. When the joystick ispushed forward (backward) both motors areactivated and drive the car forward (reverse). Whenthe joystick is pulled left or right the steering motoris engaged and the drive motors are activated inforward.

Steering MotorA 12 volt windshield wiper motor is used turn thefront wheels. The steering motor is connected to thefront axle through a pitman arm, tie rod, andsteering arm. The steering motor interfaces with thesteering control circuit through a contact arm andthree limit switches. Mechanical stops were alsoincluded to guard against over steering or motordamage should one of the limit switches fail tooperate properly.

Steering Control CircuitThe steering motor control circuit components are:four SPDT relays, two 3PDT relays, and three limitswitches. The limit switches feedback steeringposition from the steering motor contact arm. Whenthe center limit switch is engaged the steering motorremains idle until the joystick is moved to the left orright position. When the joystick is moved into theleft (right) position the steering motor activates andthe front wheels are turned until the left (right) limitswitch engages and the steering motor stops.Moving the joystick into the forward or reverseposition reverses the direction of the steering motorrotation and the front wheels are turned untilcentered.

Further work to provide for smooth accelerationshould be considered. The joystick circuit activatesthe drive motors in the same manner that theoriginal foot pedal, The pulse felt as the motorsreceive full power may not be suitable for allchildren

The final cost of the project, including the cost of theoriginal toy jeep, was approximately five hundreddollars ($500.00).

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A Wheelchair WorkstationAn Adjustable Wheelchair Workstation For a

Quadriplegic ChildDesigners: Virginia Byrd, lames Cunard, Ray Kesterson,

Lyndu Lebel and GeoflPain terDisabled Coordinators: Robert Perry, Rehabilitative Engineer

Supervising Professor: Dr. Cecil H. RamageDepartment of Mechanical Engineering

University of Sou th AlabamaMobile, AL 36688

INTRODUCTION SUMMARY OF IMPACTThe wheelchair workstation provides the ad-justability and stability required by the client. Theserequirements include adjustments of horizontal andvertical position, angle of equipment, and distancefrom user. The workstation provides a large workarea that can simultaneously accommodate severalpieces of equipment, including a page turner,typewriter, computer and/or other devices ormaterials. The user is positioned at the workstationand adjustments are made accordingly.

There are many wheelchair trays available forhandicapped people with partial use of their arms.These trays do not meet the needs of thisquadriplegic client (complete paralysis of the bodyfrom the neck down). He also requires permanentrespiratory assistance through a tracheotomy. Therespirator severely l imits his vert ical headmovement; however the horizontal movement isless restricted.

The support structure of this design is an A-framekeyboard stand. These music stands are lightweightand adjustable yet high strength, with a factoryrating of 150 pounds per support tier. Lockingcasters were added to aid in positioning theworkstation without reducing stability.

The client previously used a fixed position lap tray,which could be used to support his page turner, butcould not be used for any task that used mouth stickaction. He attends fourth grade, and his teacher oran aide must hold his paper for him to write usinghis mouth stick. His lap tray could not be used witha t y p e w r i t e r o r computer to enhance his

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communication and learning skills. Two wheelchairworkstations were built, one for home and one forschool use. The client can use the workstationwithout requiring his mother to transport moreequipment. The classroom workstation also couldbe used by other students. The school year hadended before the client received his workstations,therefore t h e w o r k s t a t i o n s h a v e n o t b e e nimplemented in the classroom sett ing. Theworkstation for home use has been delivered andhis mother feels that it will help him access moreactivities independently.

TECHNICAL DESCRIPTIONThe major design factors are the nature and theextent of the user’s physical limitations and theactivities to be performed at the workstation. Theoriginal request was for an adjustable tray thatattached easily to the wheel chair. After in-vestigation, it was determined that the workstationshould be separate from the wheelchair for thefollowing reasons:

1. The workstation requires no additionalmodification to the wheelchair.

2. The workstation allows easy access to theclient should he need assistance.

3. The workstation allows more than one ac-tivity to be available at a time.

Two alternatives were considered for selection ofthe workstation components:

1. New design and fabrication.2. Purchase existing equipment and modify as

needed. The decision to purchase andmodify was m a d e b a s e d o n t h e s econsiderations: availability, aesthetics, costand time.

The workstation was designed using keyboardstand hardware. The hardware consisted of two 60inch A frame leg singles, two 48 inch support tiers,one 48 inch stabilizing tier, 6 support bars, and allhinges and fittings to attach the horizontal tiers.Wing screws, hex screws and knobs for adjustmentswere also supplied with the stand hardware. Thewooden formica trays were designed and fabricatedat a cabinet shop. Plastic trays were available withthe keyboard stand but these were expensive andwould have required modification. The bottom tierholds two independent trays of 21 x 14 x 3/4 inches.The top tier holds a single 36 x 14 x 3/4 inch tray.The trays are mounted on the support bars by usingscrews.

The stock casters for the stand were also expensive.Two-inch locking casters were purchased and amounting assembly was designed and machined.Aluminum bar stock was machined to fit insideeach A-frame leg. Aluminum plate was machinedto the required angle and welded to the bar stock.A caster was then bolted to each plate.

The total cost for both workstations, excludingshipping cost, was approximately four hundred andforty dollars (!§440.00).


Portable Wheelchair Access RampsDesigners: Dan Unger, Sing Ung

Rehabilitation Professional: Robert PerryVocational Rehabilitation Services

Supervising Professors: Dr. C. Ramage, Dr. E. TsangDepartment of Mechanical Engineering

University of South Alabama, Mobile, AL 36688

INTRODUCTIONPersons confined to a wheelchair often encounterobstacles that are difficult for their wheelchairs toovercome. These people are denied access to manyplaces because of these obstacles. The person mayfind it necessary to set up some sort of temporaryramp at a place he or she frequently visits, such asthe home or office of a client or relative. If aprolonged stay is necessary or desired, a portableramp of some sort would allow the person toovercome these obstacles without the assistance ofanyone else.

SUMMARY OF IMPACTThe person these portable wheelchair ramps weredesigned for was very pleased with the ramps. Henow can visit friends and relatives that have housesnot equipped with access ramps. With theseportable ramps installed, he will find it much lessdifficult and demanding to maneuver in and out oftheir residence, creating a feeling of much moreindependence. An additional benefit of designingthe access ramps is that more than one personconfined to a wheelchair can use the ramps. It isn’tnecessarily designed for a particular wheelchair.The ramp designed can be used by the majority ofwheelchair makes and models on the market.

TECHNICAL DESCRIPTIONThe ramp design chosen is a lightweight portableramp that could be set up to allow the person accessover the curb. The American National StandardsInstitute (ANSI) recommends that wheelchair rampshave a slope of 1 to 12. For each inch of height theremust be 12 inches of horizontal projection. ANSIalso recommends that the ramp be 36 to 48 inches inwidth and have side rails at least 2 inches in heightto prevent the chair from rolling off the sides of theramp.

The ramp designed in this report consists of twoseparate narrow ramps, one for each side of thewheelchair. The two ramps will be positioned at awidth that would allow both sides of the chair toroll up the ramp. Each side of the ramp consists ofthree different sections that attach to each other. Toovercome a height of 18 inches, it is necessary toattach three sections per side. The width of eachsection is 5.5 inches. The side rails are 2.11 incheshigh. The material to be used in the ramp design isa lightweight, yet strong aluminum channel.Because of the constraint regarding the storagespace available for the ramp, it is necessary to havethe ramp separated into three six-foot sections. Abracket is used to provide support at the joints. Theapproximate cost was $435 for materials.

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Carousel Bookshelf Design For Individuals RestrictedTo A Wheelchair

Designers: Shane /ones, Walter Lastinger, Wendy ThorpRehabilitation Professional: Robert Perry

Vocational Rehabilitation ServicesSupervising Professor: Dr. Cengiz Topakoglu

Mechanical Engineering DepartmentUniversity Of South Alabama

Mobile, AL 36688

INTRODUCTION This consisted of a literature search throughmanufacturer’s equipment catalogs for the disabledfrom which the project group was unable to obtainany useful information.

The objective of this project was to design abookshelf that would give an individual confined toa wheelchair or a seated position access theapproximate number of books that a standardbookshelf would contain. The operator must beable to retrieve any one book from the shelf. Thistask must be able to be accomplished by someonewith limited use of their hands and a minimalrequirement of physical strength. The preliminarydesign of the bookshelf was begun by researchingwhat equipment was available on the market.

SUMMARY OF IMPACTThe individual receiving the bookshelf has placed itin his office and found it to make many books andcatalogs within reaching distance, therebyupgrading his ability to perform his job.

TECHNICAL DESCRIPTIONThe bookshelf will be similar to a carousel. Itsphysical dimensions are a carousel shelf of thirty-two inches square, and a total height from the floorincluding the support pedestal of approximatelyforty-eight inches. The bookshelf will contain threeshelves that will be equally spaced from the base ofthe carousel. The support pedestal for the carouselwill be rigidly attached to a base that will rest on thefloor. The pedestal will extend upward through acircular hub that has been cut in the center of eachof the three shelves. A tapered roller bearing with abearing housing will be attached to the circular hubof each carousel shelf. The support pedestal willthen thread through each roller bearing to supportshelves. The bookshelf can be rotated by applying aforce to the outer edge of the carousel.

The approximate cost of materials for the bookshelfwas approximately $285.


A Flatware - Napkin Rolling DeviceAn Aid For a Cerebral Palsy Worker

Designers: Virginia Byrd, James Cunard, Ray KestersonLynda Lebel and GeoflPainter

Disabled Coordinator: Todd Perkins, Employment SpecialistUnited Cerebral Palsy

Supervising Professor: Dr. Cecil H. RamageDepartment of Mechanical Engineering

University of South AlabamaMobile. AL 36688

The flatware-napkin rolling device was designed toallow an adult cerebral palsy client perform the taskof rolling flatware into a napkin. The designincorporates a three-roller mechanism mounted on atrack with a continuous beltloop. The device’ssupport frame is constructed of wood and a pair ofdrawer guides. The power source to supply therolling action is a low-speed AC motor. The userplaces the napkin and flatware onto the belt andinitiates the rolling action by a lever-switchmechanism. The final product is a tight and neatflatware-napkin roll.

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Chapter 20: University of South Alabama 313

SUMMARY OF IMPACTThe user of the flatware-napkin rolling device is anadult male who has cerebral palsy. He had beenemployed by a restaurant to roll flatware placesettings into napkins. He was unable to perform thetask satisfactorily and was dismissed. Since thisperson desires similar employment, a special aid toallow him to properly perform his job is needed.The napkin rolling device has not been tested with acerebral palsy client at this time. However, it hasbeen tested several times using students performingthe operation with their non-dominant hand.

TECHNICAL DESCRIPTIONThe flatware-napkin rolling device provides therolling action that allows flatware to be rolled into anapkin. The main components of the design are themotor, the belt drive system, and the supportstructure.

The MotorThe motor is a 72 RPM Bodine capacitor motor witha rating of l/70 HP.. The gearhead ratio is 23:lwith 10 in/lbs of torque. A flexible rubber hosecoupling is used to attach the motor axle to the axleof roller 1.

The Belt Drive SystemThe belt drive system consists of three Ultra HighMolecular Weight (UHMW) plastic rollers withdimensions of 2.375 inch diameter by 14 incheslong. A typewriter roller is used as an idler to holdthe belt against the drive roller. A spring beneatheach end of the idler roller axle maintains contactwith roller 1 and prevents the belt from slipping.The belt is made of rip-stop nylon fabric.

Support StructureThe motor and belt drive system are mounted on abase of 35 x 19 x 3/4 inch birch plywood. Drawerguides (ball bearing type) are mounted between thebase and the roller table. The axles of rollers 1, 2and 3 are 0.25 inch diameter brass rod its rollingaxis. The ends of each axle are inserted into holesdrilled into UHMW plastic pillow blocks. Theproperties of the UHMW plastic are such thatbearings are not needed. The supports for Rollers 2and 3 attach to the roller table. The supports forRoller 1 and the idler roller attach to the base.

Brief operating instructions are as follows:

I.II.

III.

IV.

V.

VI.

Place the napkin on the belt.Place the flatware on the napkin betweenrollers 1 and 2.Fold the napkin over the flatware asneeded.Use the handle to move rollers 2 and 3 as aunit toward roller 1.As the handle is moved toward the left, theweight of the flatware causes the belt toform a pocket between rollers 1 and 2.The full left position activates the motorand the rolling action begins.

VII. As the roll is completed, the operatorreturns the handle to its original position,which deactivates the motor.

The final cost of the project was approximately onehundred dollars ($100) for the motor and the belt.The low cost of this project was made possible bydonation of much of the building materials.


Platform Design To Aid In Balance RehabilitationDesigners: Shane Jones, Walter Lastinger, Wendy Thorp

Rehabilitation Professional: Dr. James WallPhysical Therapy Department

Supervising Professor: Dr. C. TopakogluDepartment of Mechanical Engineering

University of South AlabamaMobile, AL 36688

INTRODUCTION Making therapeutic exercises more enjoyable andThe purpose of this project was to design and buildthe mechanics of a platform to aid in balancerehabilitation. The project was initiated by Dr.James Wall of the Physical Therapy Department atthe University of South Alabama and was fundedthrough the National Science Foundation.

challenging for the patient, the platform wouldserve as a motivational tool having the versatility ofbeing used with different types of video games. Theplatform also would benefit the physical therapistsby providing more quantitative data and recordsthan the traditional exercises.

The primary objective was to build a low costplatform that would determine the position of thecenter of gravity of a standing person. The staticboard would attach to a home computer through itsgame port. Acting similar to a joystick, the boardwould detect movement of the center of gravity thatwould result in movement of the on-screen cursor.

The mechanical engineering senior project groupwas restricted to designing the mechanics of theplatform and determining the method for findingthe center of gravity. An electrical engineeringproject group was given the task of developing andoptimizing the circuitry to the computer.

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SUMMARY OF IMPACTHemiplegia is a condition that affects stroke patientsmaking it difficult for them to balance and walknormally. Similar problems exist with clinicalconditions such as cerebral palsy, Parkinson’sdisease, and lower l imb amputat ions. Thetherapeutic exercises used in treating these balancedisorders are tedious and repetitive, and thepatients lack the motivation to continue theexercises. With this type of exercise tool, thepatients will enjoy the exercises, and the result willbe a more complete recovery for the patients.

TECHNICAL DESCRIPTIONThe resulting platform dimensions are three feetlong by two feet wide by six inches high. Thesedimensions keep the board compact but allow forcomfortable standing. The extra length of the boardalso gives the space needed for the person to take asingle forward step.

Chapter 20: University of South Alabama 315The frame is made of one inch square aluminumt u b i n g , b e c a u s e a l u m i n u m i s d u r a b l e y e tlightweight. Stain gaged aluminum beams arewelded on each of the four sides of the frame. Thecantilever beams on the longer sides point outwardto avoid overloading the connection point. Theplatform cover is made of three-quarter inchplywood bolted to the beams.

There are two Omega general purpose strain gageson top and two on the bottom of each beam toincrease the re l iabi l i ty of the readings andcompensate for temperature effects. The signalleaving the stain gages passes through wheatstonebridges, filters, amplifiers, and an analog to digitalconverter as designed by the electrical engineeringproject group.

The approximate cost of the mechanics of theplatform is $230.


Modifying An Apartment Entrance Way For AQuadriplegic Resident

Designers: W. JeflNaoman and Edgar WongContact: Gloria Bragg

Rehabilitation Professional: Robert PerryVocational Rehabilitation Services

Superoising Professor: Dr. Edmund TsangDepartment of Mechanical Engineering

University of South AlabamaMobile, AL 36688

INTRODUCTION SUMMARY OF IMPACTAn apartment entrance has been modified so that aquadriplegic resident can enter and exit theapartment as well as lock and unlock the door. Thedoor opening mechanism is based on a standardl/3 horsepower Sears garage door opener. The unithas been modified to mount securely to the wallopposite the door, and the sprocket on the outputshaft has been replaced by a spool. One end of arope is attached to the spool and the other end is at-tached to the door. When the motor is activated therope winds up to the door. When the motor isactivated the rope winds up on the spool and thedoor opens. The rope unwinds and a door closerpulls the door closed when the motor is reactivated.The handle on the existing dead-bolt lock has alsobeen modified so that it can be operated withoutusing any gripping force. With this modification,our client can lock and unlock her door manually.

The client had no way of opening and closing herdoor or locking and unlocking her door on her own.That was not an acceptable situation because shehad no way to exit her apartment in an emergencyor to lock her door if she felt threatened. Thecomponents that were developed provide a solutionto both problems. Just as important, they give theclient an added amount of independence. Althoughshe can not drive herself, she can now leave herapartment to visit neighbors or just to enjoy a prettyday. She can now let visitors into her apartment atwill and lock her door after they leave. In short,these solutions have increased her ability to functionas an independent individual.

TECHNICAL DESCRIPTIONAn apartment entrance has been modified so that aquadriplegic resident can enter and exit theapartment as well as lock and unlock the door. Themodifications performed were targeted toward aspecific individual and are meant for her personaluse. The criteria for this project were as follows:

1) The door opening mechanism must notdetract from the existing architecture.

2) No solution can seriously alter the con-struction of the doorway.

3) The solutions must not make the apartmentless accessible, even in the event ofcomponent failure.

4) The solutions must be safe to operate.5) The door opener must be operated by remote

control.6) The total cost of the solutions must be under

$500.

The door opening mechanism is based on a Searsl/3 HP garage door opener. This garage dooropener was chosen because of its low price, remotecontrol operation, adaptability, and safety features.Metal mounting braces were attached to the existingmounting locations on the opener to provide ameans to attach the opener to the available studsand rafter. The door opener was mounted upsidedown (with the output shaft vertically downward)against the wall adjacent to the door. The sprocketthat was originally mounted to the output shaft wasreplaced in favor of a spool. A rope was thenwound around this spool and the free end wasattached to the door. When the motor is activated,the rope is wound on the spool and the door isopened. Upon activating the motor again, themotor drives the spool in the opposite direction andthe rope unwinds. A door closer then pulls the door

Chapter 20: University of South Alabama 317closed. The number of turns of the spool is ad-justable by limit switches. Also, if something is inthe way of the door or the operator attempts to openthe door while the door is latched closed, the openerwill stop and reverse to remove the tension in therope and relieve stresses in the door and mountinghardware.

It was decided that the deadbolt lock originally onher door would be modified so that the client couldoperate it manually. The door originally has threelocks; a door knob on bottom, a privacy dead boltabout 5 inches over the door knob, and a keyeddead bolt about 5 inches over the first dead bolt. Tomove the keyed deadbolt into the client’s reach, theposition of the knob and the keyed (top) deadboltwas interchanged. To allow the client to operate thelock now that it is within her reach, the thumb turnoriginally on the keyed deadbolt was replaced by aloop made of l/8 inch diameter steel rod. The clientmerely puts her hand into this loop and rotates it 90degrees to lock and unlock the deadbolt. The knobwas also prevented from latching so that it wouldnot have to be turned before the door opener wasactivated. Since the door is not latched when it isclosed, the door closer was adjusted to providesufficient force to keep the door closed in a fairlystrong wind. If, in very strong wind or other un-foreseen circumstances, the door closer did notprovide enough force to keep the door closed, thedeadbolt lock could be used to stabilize the door.

The final cost of the project was less than $250. Theleast expensive commercial door opener that wasavailable cost between $800 and $950 depending onthe features ordered. These devices did not includea method of locking and unlocking the door.

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