Disabled Village Children A guide for community health workers, rehabilitation workers, and families

PART 3 WORKING IN THE SHOP: Rehabilitation Aids and Procedures

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CHAPTER 66

Designs for 6 Basic Wheelchairs

There are dozens of designs for low-cost, 'appropriate technology' wheelchairs. Some are lower cost and more generally useful than others. In PROJIMO, we have built many different wheelchairs. In this chapter we give designs for 6 of the ones that we have found most useful. Each has advantages and disadvantages.

AHRTAG wood wheelchair made from a child's chair, bicycle wheels and axles at front, one rear caster		Advantages: the simplest and one of the cheapest chairs to make; easy to modify or adapt; very little welding needed; can be built in one day by someone with some carpentry skill; low cost. Disadvantages: Single, small rear wheel makes it difficult for either the child or helper to push over rough ground or up curbs. Fixed footrest makes it hard for child to climb in and out without tipping chair forward when weight is on footrest. Sideboard makes transfers to side and lifting child from behind difficult.
Re-bar and woven plastic wheelchair steel construction rod frame with woven plastic seat, back, and footrest		Advantages: simple design; fairly low-cost re-bar is easy to bend; plastic woven seat is comfortable and easy to clean; slide-away footrest makes getting in and out easier. Disadvantages: Builder needs welding skills, relatively heavy and not as strong as tubing chairs. Big bumps may bend the chair out of shape.
Square metal tube wheelchair frame bolted together		Advantages: strong, stable metal chair that can be built with nuts and bolts (welding needed only to attach front wheels). Flat surfaces make it easier to put on wood adaptations; fairly low cost. Disadvantages: more work and skill needed than for above chairs; design more complex; slightly higher cost than wood chairs.
Wheelchair with lying board made of steel tubing, with removable wood lying board		Advantages: useful for active child who must lie face down to heal sores or stretch contractures. When board is removed, it is a regular wheelchair, low cost; very adaptable. Disadvantages: requires welding (but a simpler model can be made of wood); does not fold; board takes up a lot of space; stiff ride.
Plywood frame wheelchair with 20 inch bicycle wheels and axles, and 2 front casters		Advantages: attractive; lightweight; low cost, easy to make and adapt. Caster wheels in front (not in back) make it easier to go over rough ground and curbs. Adjustable push-away footrest makes positioning and getting in and out easy. Disadvantages: Plywood and double casters increase cost (although it is still a cheap chair). Plywood (if not marine grade) may come apart in wet weather. Bicycle axles may bend or break with a heavy child or rough use.
Metal tube folding wheelchair made from thin-wall steel tubing; strong axles with machinery bearings		Advantages: Chair folds for transporting or storage; very tough; flexible design good for uneven surfaces; good for side transfers; a very high-quality chair if well-made. Disadvantages: needs more skill (tube bending, welding, exact fittings, wheel spoking, etc.) to build; relatively costly; hard to adapt.

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Tools needed for making wheelchairs

Ideas for setting up a workshop for disabled workers are discussed in Chapter 57 and Page 603 of Chapter 64. How you equip your workshop for making wheelchairs will depend on (1) how much money you have (or can borrow) to do it, (2) the kinds of chairs you hope to build (metal or wood), (3) the skills, physical and mental abilities, learning potential, and responsibility (regarding safety) of the workers, (4) the availability of electricity and power tools, (5) how many persons will be working, and (6) how many chairs you hope to produce.

Here we list the basic equipment you will need for making the 6 wheelchairs described in this chapter. Many choices are possible. More specialized parts of the work can be done by outside craftspersons. For example, in a wheelchair production center in Belize, axles must be machine tooled on a metal lathe. Local machine shops cooperate by doing this free.

CODE AN - Absolutely necessary N - A big help, but you might do without it (N) - Necessary only for axles ? - Depends on model	TYPE OF CHAIR
	wood chair	re-bar and woven plastic	square metal tubes with wood seat and back	wheelchair with lying board	plywood	round metal tube Terms
TOOLS REQUIRED bench vise	N	AN	N	AN	(N)	AN
tubing bender				AN		AN
welding (brazing) equipment	(N)	AN	N	AN	(N)	AN
metal saw	(N)	AN	AN	AN	(N)	AN
wood saw	AN			AN	AN
hammer	AN	AN	AN	AN	AN	AN
wrench (set or adjustable)	N	N	AN	AN	N	AN
metal file and/or grinder	(N)	AN	AN	AN	(N)	AN
screwdriver	AN	AN	AN	AN	AN	AN
sewing equipment (hand or machine)			?	N?		N?
drill (hand or electric)	N	?	AN	AN	N	AN
drill bits for metal			AN	AN		AN
drill bits for wood	AN		AN		AN
spoke wrench	?	?	N	N	N	N
bicycle pump	?	?	?	?	?	?
center punch	N	N	N	N	N	N
tape measure	N	N	N	N	N	N
carpenter's square	N	N	N	N	N	N

Terms for metal tube or bar used to build wheelchairs

• Thin-wall refers to thin steel tubing often used for electrical wiring work and sometimes for lightweight metal furniture.
• Thick-wall refers to heavy weight pipe such as the one used in plumbing.
• Re-bar refers to solid metal rod, usually used to reinforce cement.

Jigs or guides for more exact welding

For making the metal tube chairs and the welded wheel mounts and handrims of any of the chairs, your work will be easier and more exact if you make or purchase certain 'jigs' or guides to hold parts in the right place while you weld them. For example, to weld the front caster fork you can make a 'jig' like this.



Details on 'jigs' and other techniques for making different wheelchair parts are well described in Ralf Hotchkiss's book Independence Through Mobility (see reference on Page 604). We strongly recommend it to any group planning to make wheelchairs.

Notes on measurements For some of the wheelchair designs in this chapter, we give the measurements for a standard child's or adult's model. Be sure to adapt the measurements to the size and needs of the particular child.

In many countries inches (") are used for measurements of certain things, and centimeters (cm.) for others. We therefore also use both. Centimeters is abbreviated cm. andinches is abbreviated ". Two inches is written 2". 1" equals 2.54 cm. You can use the scale on the edge of this page (and on the inside back cover) to change inches to cm.

615

AHRTAG WOOD WHEELCHAIR

(Somewhat modified from AHRTAG manual, see Page 604.)

The AHRTAG wheelchair is built onto an ordinary child's wood chair. Measurements should be adjusted to the child's needs.



A webbed plastic seat lets air move through it and can be easily cleaned.



It uses standard 20 " x 1 3/4 " bicycle wheels and axles.



Basic carpentry tools are needed to build this wheelchair. It can be made in one day by someone with basic carpentry skills. The local blacksmith may be able to help weld together the wheel supports if you cannot. It is easy to add positioning aids or make other adaptations. The cost in Mexico using new materials is about US $40.00.

AXLES WARNING: Use standard bicycle axles this way only for children under 20 kg (50 lbs.). A heavier child, or rough use, will bend or break the axle. For children over 20 kg., use a stronger axle (see Page 623). Or support the bicycle axle from both sides (see Page 598).

616

CASTERS This backward extension distributes weight better and keeps chair from tipping backward on hills. Two back casters are more stable and make it easier for the wheelchair to go up curbs.

For brake designs, see Page 601 and 623. For other pictures and models of the AHRTAG wheelchair, see Page 526, 592, 600, 601, 604, and 624.

RE-BAR AND WOVEN PLASTIC WHEELCHAIR

Total cost using new parts is about US $40.00.



Weave back, seat, and footrest with ribbon, local wicker, cane, rattan or polyethylene plastic.

Or use thin, lightly stretched strips of car inner tube, or canvas webbing.

For front fork and casters, use factory made casters or make your own (see above, and Page 597, 619, and 623).









SLIDE-OUT FOOTREST



Foraxle designs see Page 597, 598, 615, and 623.

MATERIALS NEEDED 1/2" re-bar (4 1/2 meters) inner tube strips bicycle wheels (2) front casters (2) webbing for seat

617

SQUARE TUBE WHEELCHAIR

This wheelchair, like other steel tube chairs, should use only thin-wall tubing. Total cost in Mexico using new parts is about US $40.00. To keep costs down, check with various sources of materials and ask at small fix-it shops for advice and possibly even some free scrap material. Metal scrap heaps are great for materials.





sealed bearing hub (see Page 597, 598, and 623)

caster wheel mount (see Page 616, 619, and 623)

MATERIALS NEEDED thin-wall square tubing (1" x 3.64 meters) thick canvas cloth (1 square meter) galvanized steel tube (1/2" x 66 cm.) bicycle wheels (2) (20" x 1.75 ") caster wheels (2) (wood or rubber) threaded rod (3/8" x 38") (Use extra 20" to bend 4 U-bolts.) 2 front casters 21 3/8" nuts and 12 screws for seat and back supports

HOW TO MAKE YOUR CHAIR Review drawings. Adjust measurements to fit child. Cut all sections of square tubing. Make sure that matching tubes are equal in length. Drill holes in bottom tubes and pass the threaded rod through them. Adjust nuts until a 'V' is formed. (Weld tip of 'V' for extra strength.) Drill all holes in seat tubes. Pass threaded bolt through seat holes. Drill holes in back support tubes and front caster tubes. Bolt to frame. Weld axle nuts to ends of axle tube. Drill holes for U-bolts and bolt axle tube to frame. Weld front caster forks to front tubes. Sew cloth back and seat supports. Screw into place. Cut out and bolt wood footrest to frame. (Use wedges to get the angle right.) Attach axle tube with U-bolts and put on the wheels. Paint frame to help keep tubes from rusting (if not galvanized).

618

WHEELCHAIR WITH LYING BOARD

This is useful for an active child who must lie face down to heal pressure sores or to stretch hip and knee contractures.

The board is sloped so that the child can play, look ahead, and move about more easily. If necessary, you can make the lying board adjustable so that the child can rest lying flat. This helps to improve circulation and to prevent swelling of the feet.

After the pressure sores heal, the lying board can be removed and the frame is easily adapted to form a lightweight wheelchair. The cost for materials in Mexico is about US $40.00.

The design we show uses a simple, non-folding steel tube wheelchair frame with a wooden lying board mounted on top. However, many other designs are possible. (See, example, the photo of a lying and standing wood wheelchair on Page 190.)

WITH LYING BOARD Lying-board should be well padded with thick foam rubber. If necessary, cut out a hole for urine to pass through (line hole with thin plastic so the foam rubber stays dry). For tall persons, place the casters farther from the big wheels to help prevent tipping.

WITHOUT LYING BOARD and with other additions

THE LYING BOARD

SIDE VIEW

Attach thin wood or plywood boards with small screws so that they can be easily adjusted to leave open spaces under bony parts or sores.



TOP VIEW



Make the board and wheelchair just a little wider than the child's hips.









The board attaches to the chair with angle irons orwing bolts. You can make wing bolts by brazing a stiff bent wire to a bolt.

619

FOOTREST

Use thin wood or plywood. (Pad sides and bottom well to prevent sores. Examine feet daily.)



FRONT CASTER WHEEL



REMOVABLE HANDLE



You should now have enough information to make a wheelchair with a lying board without step-by-step instructions. Adapt it, and make it the size to fit the child that needs it.



Page 618

CAUTION: Remember that a child who has some pressure sores can easily get new ones. Be sure the child lies and sits so that there is little or no pressure over bony places. Examine her whole body at least once a day and try to keep her dry.

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PLYWOOD FRAME WHEELCHAIR

This can be easily built by someone with basic carpentry and welding skills. (Cost in Mexico using new materials is about US $40.00.) Positioning aids (head rest, hip pads, etc.) can be easily added. The chair can be designed to meet a child's particular needs. For example, if the child sits well without extra support, the tops of the side pieces can be removed to allow more freedom of movement.

A plywood frame is a low-cost alternative to metal. However, if not made well, or if left out in the rain, the chair may weaken and the plywood can split. As with any wheelchair, it must be protected from misuse, periodically examined for weaknesses, and promptly repaired.

See model on Page 621






For active children the wheelchair can be strengthened by reinforcing all joints and by adding strong hubs and axles (see Page 623).

HOW TO MAKE YOUR CHAIR Review drawings of chair and adaptive equipment. Cut out the two side pieces to the same shape; sand with sandpaper. Cut out back support, seat, and bottom piece of chair; sand with sandpaper. Screw or nail seat and bottom piece to back piece. Screw or nail side pieces to seat, bottom, and back. Check that all pieces are lined up straight. Then add glue and more screws or nails for strength. Cut out footrest and guide brackets for footrest. Screw or nail guide brackets to side pieces under seat. Bolt front casters to chair and assemble rear axle tube. Drill holes in side pieces for axle tube; mount tube and rear wheel. Let glue dry 1 to 2 days; check for strength of all wood joints.

MATERIALS NEEDED 3/8" plywood (1 sheet) 20" bicycle wheels (2) small caster wheels (2) 1/2 steel tube (66 cm. long) wood glue sandpaper screws nails 1/2" by 1/4" wood strips (6 X 46 cm. long)

These measurements are for a 4 to 8-year-old child.





621

A plywood wheelchair with many adaptations

This wheelchair has a variety of additions sometimes needed for a small child who has poor body control, head control, and urine or bowel control. The head support and armrests fit into wooden holders and can be easily removed. A lap table can be easily added. Holes can be cut out for chest and hip straps for extra support.

head positioner swing-up armrests padded hip and shoulder positioners potty bowl holder with leg separator Pull out to empty potty. Tree branch holds stiff legs apart. lap table The lap table should be cut to fit closely around the wheelchair sides. The same wooden brackets for the armrests keep this table in place. If the table wobbles, you can use small slats to strengthen the table. If the knee separator is made a bit higher, the table can rest on top of it and prevent any dips.

SPRINGS FOR ALL 4 WHEELS

This plywood wheelchair has a springy ride. Old inner tube rubber strips connect the rear wheel axle to the wood strips holding the front caster wheels. These wooden strips should be strong enough to withstand the springy motion of the front casters.

Special cut-away slots allow the rear axle to move up and down freely. Other cut-away slots in the bottom of the wheelchair allow for the inner tube strips to be wrapped around the wooden caster strips. The tighter the inner tube strips are wrapped, the less bouncy the ride becomes.

To build your own strong rear hub and axle, see Page 623. If you want to use hubs from bicycle wheels, see Page 597.

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WHIRLWIND STEEL TUBE WHEELCHAIR

The whirlwind (ATI-Hotchkiss) wheelchair is a very strong lightweight folding chair. On rough ground it rides more easily and lasts longer than more costly factory-made chairs. If it breaks, it can be fixed by the neighborhood metalworker. It is narrow and helps the rider to move about crowded rooms.

The frame of this chair is made of thin-wall steel tubing that is easy to shape by someone with basic mechanical and welding skills. It can be built in about 4 days in a small metalworking shop. More than 10 groups of disabled mechanics throughout Latin America are building this wheelchair- often at less than a quarter the cost of imported wheelchairs.

Most materials for this chair can be obtained locally. It uses standard 24" (or 26") bicycle wheels. The extra strong hubs (see Page 623) use standard small machinery bearings (which can often be obtained used for free or at low cost from electric machinery repair shops). The axles are 5/8" (1.6 cm.) steel bolts. Seating is canvas (heavy cloth). If the small front wheels are not available, you can make them out of wood (see Page 597 and 616).



The curved fender bar that follows the shape of the tire makes transfers easier. The lightweight folding footrests are narrow at the front, for moving more easily in crowded spaces.

Plans for making hubs, casters, and brakes are on the next page. Complete plans for making this wheelchair are in the book Independence Through Mobility (see Page 604). The book is essential for anyone planning to build this chair.

MATERIALS NEEDED thin-wall tubing (from 1/2" to 1 1/4") thick-wall tubing (5/8" inside diameter) thick canvas or nylon cloth (2 meters) square tubing (thin-wall) bicycle rims and spokes (24" or 26" diameter) caster wheels (2) used sealed bearings (8) re-bar steel (3/8" round) flat bar steel (1 /16" x 3/8") axle bolts (4) (5/8" x 5") washers (4) (1" diameter, 16 upholstery) screws (8 upholstery) machine screws (8) (1/4" x 1 1/2") paint or chroming chemicals bronze welding rod, flux bicycle tires and inner tubes (24")

FOLDING FOOTREST

X-BRACE

For a photo of this chair, see Page 536.

623

DETAILS OF HOW TO MAKE WHEELCHAIR PARTS

(can be used with many wheelchair designs)

HEAVY-DUTY WHEEL HUBS A thick bolt should fit tightly inside bearing. Bearings should fit tightly inside outer steel tube. Carefully mark and drill the outer steel tube for spoke holes. Spacer tube fits over axle bolt and holds bearings against spoke heads. Note: Used sealed bearings with a 5/8" inner diameter can often be obtained free or at low cost from electrical tool and appliance repair shops. These used bearings often last longer than standard wheelchair bearings. To attach the heavy-duty hub to a wood chair, you can weld the thick-wall tube to a metal plate. The bigger the plate is the stronger the mount.

CASTER FORK AND HUBS Mount the caster axle at least 7 cm. behind bolt. This helps prevent 'flutter' at higher speeds. For slightly different designs, see Page 597, 616, and 619.

BRAKES For other brake designs, see Page 601.

SEAT AND BACK MADE OF CANVAS (strong cloth) Cut canvas twice as wide as seat or back, allowing 4 cm. extra on sides (for seams) and at least 20 cm. longer on length. Sew canvas into a tube. CAUTION: Measure carefully. On a folding chair, the width of the seat and back control the width of the chair.

• For designs of other wheelchair parts, see the following pages:
• wheels: 594, 596, 597, 616, 619
• footrests: 600, 616, 619, 621, 622
• seats and backs: 595, 615, 616, 617, 619, 620
• axle mounts: 597, 598, 615
• tires: 596
• handrims: 601
• armrests: 599,621
• cushions: 200, 609

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Examples of locally made wheelchairs

Page 620



Page 617

Page 572

Page 199

For more examples of wheelchair designs, see Page 65, 86, 98, 189, 190, 229, 288, 343, 430, 441, and 526.

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Disabled Village Children A guide for community health workers, rehabilitation workers, and families by David Werner

Published by The Hesperian Foundation P.O. Box 11577 Berkeley, CA 94712-2577

Copyright © 1987 by the Hesperian Foundation 2nd edition, 5th printing February 1999