GOLF CART-OR FAMILY RUNABOUTFirst, it's a golf cart powerful enough to carry two adults and equipmentup steep slopes. But it's also a heart-saver for the aged, "legs" for aninvalid, and a "school bus" or shopping "car" for Mom. It featurestwin-motor drive, four speeds forward and reverse, coil-spring suspension,2-wheel brakes and tricycle steering, plus a built-in battery charger

PART I

SPEEDS UP TO 20 m.p.h. and 30 to 40miles on a single charging of the bat-

teries make this cart an ideal utilityvehicle for any home, farm or business.The cart is wide and low, both to assurestability on any terrain and to provideample room for any of several combina-tions of motors and batteries.

First step in the construction is to makethe main frame, Figs. 7 and 10, of steelchannels and angles. Arc welding is re-quired in this assembly. The next stepafter the main frame is assembled is toassemble the drive-unit frame, Figs. 7through 11. The rear cross member of thisframe is a length of 3/4-in. pipe that pivots

By Tom Riley

in two U-shaped brackets bolted to platesthat are welded to the rear cross memberof the main frame. The brackets are aloose fit on the pipe. Strips of inner-tuberubber then are wrapped on the pipe underthe brackets to provide a "snubbing" pivot.Stub axles for the rear wheels are weldedto a length of pipe to produce a completeaxle, that will give a width of 41-1/2 in. be-tween the outer sides of the tires. Thisleaves a clearance of 3/4 in. between thetires and the outer edges of the cart'smain frame. The drive-unit frame is madenarrow enough to clear the brake drumson the wheels. Coil springs used in therear suspension are kept aligned by 3/4-in.

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Versatile is the word for this golf-cart-runabout. Grandmother, Mother,Dad and the kids all find use for it

GOLF CART- RUNABOUTPART II

By Tom Riley

A FTER COMPLETING the main frame,drive-unit frame and all other work

described in Part I last month, the next stepin construction of the cart is installation ofthe batteries. Heavy-duty, 6-volt batteriesrated at 170-amp. hours or better should beused to assure maximum performance.Batteries having bolt-on connecting postsare the best for installation in the cart, asthey allow interconnection of the batterieswith inexpensive "bus bars" of 1/8 x 3/4-in.aluminum flats, Fig. 19. Screw strips of3/4 x 3/4-in. hardwood to the floorboard

WIRING

FIELD

around the batteries to keep them in place.Batteries shown in Fig. 19 are standard-sized, grouped in a rectangle and centeredin the cart. If long, narrow batteries areused, place them four in a row across thecenter of the seat space. Weld a frame of3/4-in. steel angles for a hold-down and se-cure this frame on two ends by means oflong 5/16-in. bolts passed through the floor-board. This arrangement is similar to thatused to hold the battery in an automobile.The lower, left-hand detail in Fig. 15 showshow four 6-volt batteries can be hooked

together for 12 volts, thedetail to the right shows a24-volt hookup. Note the6-volt take-off for lights.If the cart is used on thestreet, it will require ahorn and lights as well asa license. When extra ac-cessories are installed, tapeach unit from a differentbattery. This distributesthe electrical drain so thatone battery is not over-taxed. Because the bat-teries are charged as aunit, when the other threewere fully charged, thebattery from which all theaccessories were drainingstill would not be up tostandard.

Next, it is necessary todetermine the method to

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FOOT SWITCH("ACCELERATOR")

RESISTANCE COIL

. R E L A Y

IGNITION SWITCH

BATTERY HOOKUPFOR 12 VOLTS 6 VOlTS TO LIGHTS

SWITCHREVERSINGARMATURE

use for reversing the motors you are goingto use. Most traction motors have 3 or 4terminals on the outside, with a diagramprinted on the motor or terminal box, so nochanges are necessary in this type of motor.Most surplus aircraft motors will requirethat short leads be run through the brushcover to extra terminals on an insulatedbase outside the motor, as shown in Fig. 16.Reversing diagrams sometimes are sup-plied with these surplus motors, but it isbest to have an electrician check to makesure it is right. A diagram supplied withmotors used on the original cart was in-correct; it recommended reversing thepolarity of the brushes, resulting in a deadshort, because these particular motors hadgrounded armatures. Fig. 16 shows howthese were correctly reversed. It still isbest to check with an electrician beforeconnecting your motors.

The heavy-duty reversing switch re-quired, Figs. 17 and 21, is obtained inex-pensively by rebuilding an old-style 50 to100-amp. double-pole, double-throw serv-ice entrance switch. They can be obtainedat some electricians' shops because theyare being replaced in homes today withless exposed disconnects. Raise the twocenter, or hinge, jaws of the switch about3/4 in. on pipe spacers, so the blades willclear the end jaws by 3/16 in. when they arelevel, Fig. 17. Replace the two blades andhandle with two 5-in.-long copper blades,pivoted at the middle. Bolt a block of in-sulating material between the blades at thecenter, then attach a new handle. If neces-sary, reposition the four outer jaws on thebase plate so they fit under the new blades.Bolts securing all six jaws to the baseshould extend about 3/4 in. below it, so they

CHARGER DIAGRAM

115 VOLT TO 12-24 VOLT115-VOLTPLUG TRANSFORMER

25 AMP. AT 24-VOLT CAPACITY,

12-HR. TIMER SWITCH20-AMP., 115-VOLT CAPACITY

INDICATOR LIGHT

SELENIUM RECTIFIERSINGLE-PHASE BRIDGE CIRCUIT,

15 TO 20-AMP. CAPACITYAT 26 VOLTS

12 TO 24-VOLTS D.C.TO BATTERIES

HOOKUP FOR REVERSING STARTER MOTORS

NEG TO BATTERIES '12 TO 18 VOLTS

FROM SPEED CONTROL

Above, wiring diagram for reversing aircraft startermotors as corrected by builder of original cart. Jtstill is best to have electrician check motors

INSULATINGMATERIAL

COPPER ORALUMINUM STRIPS

17WIRING

(UNDERSIDE)

Reversing switch for cart, above, is made by mod-ifying switch used originally in house wiring. Theysometimes can be obtained at an electrician's shop

Photo, below, shows installation of four, 6-voltbatteries, with hold-down frame. Charger and timerare in foreground. Wiring diagram is shown at left

MAY 1958 177

REVERSINGSWITCH

GROUNDFRAME

INSULATEDBRUSH

FIELD

MAINTERMINAL

GROUNDBRUSH

Speed-control unit, above, consists of four auto-starter relays and a rectangular resistance coil

+ TO BATTERIES

TO REVERSING SWITCH ALUMINUM BUS BAR

SPEED CONTROL

2" FRAME A N G L E ,

ELECTRIC-CABLE CLAMP

BUS BAR

221 SIDE VIEW

RUBBERWASHERS

-H/B

Above, wir ing diagram and layout of speed controlshows how resistance coil is offset to keep it wel lbelow rear deck. Below, hood is marked for cutting

178

Reversing switch, above, is raised on pipe spacersso that wiring can be run in the space beneath it

can accommodate two nuts and cable ter-minals. On the underside of the switchbase, cross-connect the four outer terminalsas indicated in Fig. 17, using copper or alu-minum strips. The switch handle is a 1/4 x1/2 x 10-in. steel flat, twisted 90 deg. justbeyond the insulating block to which it isbolted. The end is ground down and thread-ed to accept a small gear-shift knob froman automobile steering-column lever.

To vary the speed of the cart motors, aspeed control is assembled from four 6-voltauto-starter relays, which pass the elec-tric current through a varying length ofchrome-nickel resistance wire, Figs. 20 and22. In operation—see Fig. 22—closing relayNo. 1 causes the current to pass through thefull length of the resistance coil, resultingin low speed. Closing relays 2, 3 and 4 giveconstantly higher speeds, with No. 4 pro-ducing full speed because it allows thecurrent to bypass the resistance coil. Useauto relays that have no connection be-tween the relay coil and its main terminals,such as for a 1946 to 1954 Plymouth. MostFord relays, for example, look the same,but have the relay coil wired internally toone of the main terminals, which will causethe 12 to 24-volt current to feed backthrough the 6-volt coils, causing either aheavy "short" or chattering of the relays.If available, 24-volt aircraft relays, whichhave silver contacts, are best. Drill holes3 in. apart in a 1/8 x 3/4 x 11-in. aluminum barand bolt the motor-side terminals of therelays to it. Bolt the four relays to a 4 x 12-in. piece of 1/4-in. hardboard, using rubberwashers as indicated in the lower detail,Fig. 22, to quiet the click when they operate.Connect the four relay housings togetherwith a small wire to provide a 6-volt ground.Making the resistance coil is a cut-and-trymatter, depending on the wire, motor typeand voltage used. Try about 10 ft. of

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1/8-in.-dia. chrome-nickel resistance wire,wrapped around a 2 x 6 to form a rectan-gular coil. Because the wire gets hot whenthe cart is running, mount the coil abovethe relays, and extending out from themas in Fig. 22. For the same reason, connectthe coil to the relays with electric service-entrance cable clamps, rather than by loop-ing the wire around the relay terminals.The clamps also allow you to tap off any-where along the coil. Connect the clampsso there is more coil between relays 1 and2, than between the others. If this producestoo slow a first speed, cut down on thelength, if too fast, add more resistance wirebetween the first two relays. The speedcontrol is bolted to the center of the 2-in.-angle crossframe with two pieces of steelangle, Fig. 22.

The 6-volt wire from the batteries andthe four wires from the relays to the "ac-celerator pedal" need be only 18-ga. strand-ed wire, secured to the underside of thefloorboards. On the original cart, the ac-celerator switch, Fig. 24, was a long-wear-ing, silver-contact type made especially forthis purpose by one of the larger golf-cartmanufacturers. Some heavy-duty surplusradio switches also can be used. They area "shorting type" switch. The wiper arm ofthe switch contacts each following termi-nals before disconnecting from the preced-ing terminal, providing a smooth action.The heavy wiring from the batteries to thespeed control, reversing switch and motors,Fig. 15, should be 6 ga. or heavier. Auto-battery cable is excellent but expensive.House-service cable can be used, but is less

AUTO-ACCELERATOR PEDAL

24

"ACCELERATOR" SWITCH(SHORTING-TYPE SWITCH)

satisfactory because it is difficult to bendat sharp angles.

The built-in charger is an optional fea-ture, but it definitely simplifies servicing.The charger shown in Fig. 19 producesmore than 20 amps, at 24 volts, and hasboth a 12 and 24-volt output. An 18-volttransformer would have to be used, if thatcurrent were used in your cart. Mount thetransformer on brackets about 1/2 in. abovethe floorboard, so wiring can be locatedbeneath it. A 12-hour, spring-wound timerswitch, such as used for large fans, ismounted under the seat. The wiring dia-gram is shown in Fig. 18.

Figs. 14 and 25 show how the two sides,rear panel and rear deck, cut from 1/2-in.plywood are attached and trimmed withlinoleum trim strips and steel angles. Theside rails on the rear of the cart are bent

SCREW

V PLYWOOD

%" PLYWOOD

MAY 1958 179

from 1/2-in. Thin-Wall electrical tubing. Thehood of the cart is formed from a singlesheet of 1/8-in. hardboard, measuring 24 x76 in. Cut this panel after it has beenclamped or screwed to the center of thefloorboard, with about 5 in. extending be-low it. Then bend and clamp the ends of thehardboard to the frame. Push it down untilthe top end assumes an even curve, thenscrew it to the floorboard every 8 in. Now,mark the vertical lines of the doorway andany pleasing curve desired for the top andbottom edges of the hood; Fig. 23. Removethe hood and cut it with a bandsaw, or cutit in place with a handsaw. The glove, orpackage, shelf, shown in the photos in PartI of this article, is cut from 1/2 or 3/4-in. ply-wood and screwed to the inside of the hoodat a convenient height. An instrument pan-el is screwed to the glove shelf at about a10-deg. angle. Install a keyed "ignition"switch and any other accessories desiredon the panel. The hand-brake lever is fas-tened to the underside of the glove shelfwith a metal bracket.

Upholstering of the seat cushion and backmay be done by a professional, or at home,if a heavy-duty sewing machine is avail-able. The cover material of the seat shouldbe weather-resistant plastic, and the fillingshould be two 2-in. layers of foam rubbercemented together. The seat cushion is as-sembled around a sheet of 1/2-in. plywood,the completed cushion resting on hardwoodstrips, right-hand detail, Fig. 25.

Note that the seat cushion is slantedslightly, to provide more comfortable seat-ing. The degree of slant will vary, depend-ing on the necessary clearance above thebatteries being used. Drill a few holes inthe bottom of the seat cushion to provideair escapes for the filling. The seat back isformed in the same manner as the cushion,except that it is assembled on a sheet of1/4-in. plywood. The completed back thenis screwed permanently to the seat back.It is necessary to have the seat cushion re-movable to permit access to the batteries.

The completed cart can be painted withany enamel, lacquer or other exterior-typefinish. The original cart was finished witha vinyl-lacquer, two-color "spatter" paint,that has the advantage of producing atough, heavy finish in one coat, and doesnot require a spray gun for application.Rubber floor matting, obtainable at mostauto-supply stores, is used to cover the reardeck, floorboards and glove shelf. Metalenamel should be used on the wheels, railsand steering column of the cart.

If the cart is to be used for golfing, twolengths of web strapping are screwed tothe top edge of the seat back. The golf bagsthen can be strapped in place. * * *

180

pipe caps bolted to spring plates at thefront of the drive-unit frame and to the 2-in. cross member of the main frame. A long3/8-in. bolt with fuller balls at each end isused to "snub" the frames together and toprevent sidesway of the drive-unit frame.The lower right-hand detail in Fig. 7 showsthe snubber bolt, springs and pivot-bracketsetups. A piece of 3/4-in. plywood is boltedto the drive-unit frame to support the mo-tors. Slotted holes in the plywood permitthe motors to be moved to allow adjust-ment of chain tension. Heavy turnbucklesare attached to the frame and to the mo-tors near the shaft ends to "hold" thisadjustment.

Wheels, which should be purchased be-fore assembling the drive-unit frame be-cause of the need for measurements, canbe of several types. For the rear, the wheelsshould have 4.80 or 5.50 x 8 turf-type tires,such as used on most golf carts. A less ex-

Spend your time improving yourgame, instead of walking. The cartgets you around in half the time

pensive substitute are wheels torn lightaircraft, which are available as war sur-plus. These have tires with a channeltread, and are complete with bearings,hubs, and spindles. Also available are 6-in. brake drums and sprockets drilled tofit the wheels. For the front wheel of thecart a rounded tire is best. A 14-1/2-in. bal-loon aircraft tire or a 16-in. standard in-dustrial tire should be used.

The fork assembly is made as shown inthe left-hand detail, Fig. 7. Either turnedbrass bushings or ball bearings can be used,pressed into a counterbored length of pipeor tubing. The latter then is welded overa hole drilled in the 3-in. frame channel,Figs. 6 and 10.

Three types of d.c. electric motors canbe used for the cart. Sprockets and chainsfrom light motorcycles are used with eachto deliver a speed of from 350 to 400 r.p.m.to the rear wheels. Aircraft starter motors,

Photo of frame front end shows location of fork,foot and hand brakes, extreme turning angle possible

Fig. 8, available as war surplus, can be usedif only moderate power is required. Al-though rated at 24 volts, they are designedfor intermittent service and should be runwith four batteries producing 12 volts,or three batteries that will provide18 volts. Most of these motors turn onlyabout 100 r.p.m., so a large sprocket isfitted on the motor and a smaller one onthe wheel. Check the r.p.m. rating of anytype motor before obtaining sprockets. Asecond type aircraft motor, also availableas surplus, is a high-speed unit that rotatesat about 5000 r.p.m., which makes it nec-essary to use a gear reducer of from 5-to-lor 10-to-l to reduce the speed to a pointwhere chains and sprockets can handle it.A third type motor, the most expensive, isa propulsion or traction motor, Fig. 9, such

168 POPULAR MECHANICS

Drive-unit frame with aircraft starter motors in- Here drive unit is f i t ted with propulsion motors,stalled. Note turnbuckles from the frame to motors such as used tor golf carts and industrial lifts

APRIL 1958 169

2" CHANNEL

2" CHANNEL

as is used for golf carts, electric lifts andthe like. They are available from the largermotor manufacturers.

Brakes for the rear wheels of the cartcan be made in two ways. If you purchasewheels with 6-in. drums, parking brakesof the external-contracting type, used onthe drive shaft of Plymouth cars, can be

'modified for use as shown in the right-handdetail, Fig. 7. A second type of brake isto bolt a double V-pulley to each wheel anduse two V-belts as "brake bands." The lat-ter brake is efficient, but wears rapidly.Arrangement of the cables for both the

hand and foot brakes is shown in Fig. 10.The parking-brake handle can be onepicked up in an auto-wrecking yard.

The seat back and three floorboards noware cut from 3/4-in., exterior-grade ply-wood. Ten 2-in.-dia. holes in the back arelocated toward the center so mud from thetires will not spatter through. These, andnine holes in the seat floorboard ventilatethe charger and batteries. The seat front,cut from 1/2-in. plywood also is attached,after being slotted for the reversing switch,Figs. 11 and 13.

Figs. 1 through 5 show just a few of the

MOTORS

DRIVE-UNIT FRAME

170 POPULAR MECHANICS

ANGLESCHANNEL

PARKING-BRAKECABLE

ANGLE

TURNBUCKIE

HEAVYSPRING

STEEL FLATEYEBOLT

LOCATION OF BASIC PARTS REAR SPRING

2" VENTHOLES

REVERSING SWITCH

"ACCELERATOR"SWITCH

SINGLEWHEEL

STEERING HANDLE

CHARGER

BATTERIES SPEED CHANGER

Springs used to counterbalance the hoods of someautomobiles are strong enough for the fork assembly

many uses for this versatile golf cart-run-about. If it is to be used by an invalid, thecart should be fitted with hand, rather thanfoot controls. The "accelerator" pedal canbe replaced with a lever-controlled switchon the instrument panel or glove shelf.Brakes also can be operated by a longlever projecting upward through the floor-board and positioned for the driver to graspit easily. An upward-projecting extensionhandle also will have to be fitted on thereversing-switch. It is important that thisswitch be handy for any driver, as it canbe used to brake the cart in an emergency.If the cart is to be driven on streets orhighways, check with city and state offi-cials for types of licenses required beforeconstructing the cart. You may find thatyour state or city does not permit a vehicleof this type to be driven on the streetsor on the highways. Next month will beshown the installation of wiring, batteryhook-up and attachment of the body sides,front and seat.

This view of cart shows neat appearance of seat andrear deck. Note reverse lever at front of the seat

APRIL 1958