442 



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. 



