Page:Popular Science Monthly Volume 92.djvu/458

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��Popuhw Science Monihly

��Positive Traction Wheel for a Motor Plow

WHEN an agricultural tractor is used for pulling plows in tenacious soil, it is necessary to augment the traction obtained by the normal adhesion of the loaded traction members and the ground with the added impulsive force secured by cleats or spurs that dig into the soil. A novel form of traction member used on a motor-driven plow of Italian design is here illustrated. It provides positive traction and is at the same time relatively free- rolling because the blade members that dig into the ground enter and leave the earth in an almost straight line. The ordinary form of fixed spur or cleat must strike the ground at an angle and push the earth back out of the way as the wheel rolls forward. This calls for the expendi- ture of power and of course reduces the efficiency of transmission. To have the spurs engage the ground with an almost direct thrust and leave it with a direct upward pull is a very desirable end to attain because there is a minimum dis-

���T

The spurs enter and leave the ground vertically

���There is no power lost in lifting dead weight with the grippers as they work vertically

placement of earth with its attendant loss of energy.

The mechanism by which the traction- augmenting blades are made to engage the ground with minimum loss of power is

��very simple and the principle involved may be clearly grasped by a study of the diagram. The spurs are in the form of drop-forged steel bell-cranks, swinging on fulcrum-pins carried between the two halves or side plates comprising the wheel. The actuating cam is attached to the fixed axle on which the wheel revolves. An eccentric strap having a plurality of con- necting rods extending to the spurs, sur- rounds the cam or eccentric, and as the wheel revolves the spurs are rocked back and forth on their supporting pins, the motion being so proportioned that when the traction blade is about to engage the ground it is approximately perpendicular. Some such form of positive traction mem- ber is almost essential because the plows are mounted at the front and are pushed, not pulled. The traction-wheel, being on the same side as the plows, must necessarily work in the loose, soft ground of the furrows. — Victor W. Page.

��Things To Be Remembered When Washing an Automobile

N'EVER try to wash the car out in the cold. Take it in where it is moderately warm; then use clear, cold water. The cold water will help to harden the varnish on a new car, thereby pre- venting abrasion. If you use any soap at all, use only a limited amount, as free acid or alkali tends to soften the finish. Soak caked mud thoroughly with a small stream of water until the mud runs off with the fluid. Don't rub the mud off. If it has frozen to the finish, keep on applying cold water until it runs away. Never use hot water. In drying the car, avoid using a chamois that contains any sand or grit. If polish is necessary, use a good grade, then rub off the surplus.

Never allow a car of fine finish to stand in a barn or stable where animals are kept. The ammonia of the manure will check and ruin the gloss.

Don't keep the garage too hot. This caution applies to what is probably the greatest enemy of the fine body finish. In an overheated garage, the body of the car gradually expands; then if the car is suddenly exposed to extreme cold, the result is plain. The sudden contraction in cooling causes the paint to check.

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