Page:Popular Science Monthly Volume 92.djvu/537

 Popular Science Monihly

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��A Bazooka Is a Musical Wimwam

THINGS are not what they seem. This ob- servation of Longfellow's is borne out by the mysteri- ous looking instrument in the hands of the soldier boy in our picture. It may look to you like a cross between a plumber's sign and an opium pipe or almost anything else, but it isn't. You will learn the truth the next time you visit a cantonment. You will learn that this queer-looking object is a musical instrument christ- ened the "Bazooka." How does it sound? Just as it looks. If you know any- thing about plumbing or steam-fitting you will at least admire the bazooka as a good piece of pipe-fitting. The rookies are exceed- ingly proud of this weird noise-producer.

Even in Turning a Corner the Brakes on the Rear Wheel Take Hold

IF you have miraculously escaped in- jury in a skidding automobile on a slippery pavement, you can readily un- derstand why the rear wheels of a motor truck semi-trailer should have been pro- vided long ago with some form of brakes controlled from the driver's seat. In tact

���Yankee Doodle came to town playing the Bazooka

���it IS quite as necessar- to have brakes on the rear wheels of a semi-trailer as on an automobile, for the reason chat the great- est portion of the trailer load is generally carried on the rear wheels. This causes them to swerve around very easily when the brakes are applied to the driving wheels of the tractor.

One of the greatest dif- ficulties in the develop- ment of such brakes has been the weaving and twisting strains set up be- tween the tractor and the trailer and the necessity of making the brakes hold when the trailer swings around at an angle to the tractor centerline as in turning corners. This difficulty has been overcome in the new type of brakes, shown in the ac- companying illustrations, by mounting the front end of the brake rod in a uni- versal joint at the center of the fifth- wheel, which supports the front end of the trailer body on the tractor platform. As a result, the brakes, which are of the conventional motor-truck type, are always operative, whether the trailer is moving up and down, as when running over rough roads, or v.hen turned, as in rounding corners. The brakes are set and re- leased by an ordinary brake-handle operated from the driver's cab.

���The illustration shows regular motor-truck brakes applied to a semi-trailer and operated through a universal joint so that they may be used on corners' and turns

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