Page:Popular Science Monthly Volume 89.djvu/928

 A Motor-Driven Brake

��The pressure of

TH E manual labor usually required for the handbrakes of a motor vehicle is avoided by an elec- tric brake requir- ing only the pres- sure of one finger to operate it. The device consists of a small electric motor which drives a tiny drum carrying a steel cable attached to the brake -equaliz- er and to the regular brake- drums. The motor is con- trolled from the steering- wheel column. The motor with its drum can be located under the body, under the driver's scat or under the mo- tor-hood, as shown in the accompanying illustration. It lakes u|) \ery little space, since it is only four inches high, six inches wide and eight inches long. It can be attached to any car simply by substituting it for the usual hand-levers, lever quadrant and brake-rod connections.

The controller consists of a two-point switch enclosed in a small Iinusing bolted to the steering-wheel column directly beneath the wheel, within easy reach of the driver's hand. A simple movement (>( the switch- handle controls the brake throughout its entire range of operation, thus making it very easy for a woman to drive even the heaviest of

��finger stops the err

���fOOT BRAKE CA6LE NOT CHANGLO

��The brake-motor is controlled from the steering- wheel column by simply moving a switch handle

��cars. The manual labor in braking is analogous to that of cranking the motor, which was done awa\- with by the electric starter, so that the ulti- mate general ap- plication of some form of mechan- ical brake is prac- ticallyassured. The electric brake draws its operating pow- er from the regular vehicle baller>' which ma\beof 6, 12 or 24 volts. The current con- sumed is said to be \- e r >■ slight.

The device contains sev- eral novel me- chanical fea- tures, the total reduction from the brake- motor to the

���Diagram showing controller and the power connection

��drum carrying the brake-cable being four hundred to one. This is secured by means of a non-reversible worm-gear on the armature-shaft which drives another gear in mesh with an internal-toothed gear on the cable-drum. Between the drum and the worm-gear is an adjustable friction-clutch b\' means of which suflirient pressure is secured to transmit the maximum braking effect, but beyond which, it will slip. After a thousand- pound pull has been ' ex- erted on the cable, the slij)- ping clutch i-omes into pla\, pre\eTitiiigan>' further pull, ^\]lile a ratchet keejis the lirake born slipping ot1. Because of the powerful

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