Page:Popular Science Monthly Volume 91.djvu/777

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���FOR PRACTICAL WORKERS

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��Flaps Used on Inner Tubes to Prevent Pinches

TIRE users do not generally realize the purpose of flaps and their influence in relation to the tire service. It is not customary to use flaps with clincher tires, not because it is unnecessary, but because of the difficulty in using a flap and stretching the tire on the rim so that it will fit properly. The beads of this type of tire are stretchable and are made approx- imately one inch less in diameter than the diameter of the rim, the object being to cause the tire to fit snugly to the rim, after being applied.

Several years ago it was a practice to use rim strips — a strip of fabric stretched tightly on the rim. These strips caused the beads to fit very snugly to clinches of the rim and protected the tube from rust and other damage. This was discontinued some time ago. While it is not necessary to use flaps with clincher tires of small size, it is really the proper thing to do with this type in sizes above 4 in., unless clips or spreaders are used to hold the beads tightly in the clinches of the rim so that the inner tubes will not be pinched or damaged. The beads of the quick detach- able clincher cases and cables of straight side cases are non-stretchable and are, therefore, made to the approximate diam- eter of the rim.

In former years tire manufacturers ce- mented the flaps to one side of the cases. The heat of the tire caused the flap to loosen, slip out of position, work under the beads, wrinkle and chafe the tubes. The floating flap, i. e., the flap loose in the case, proved to be more efficient in many re- spects. It is easier to apply the tire to the rim, the flap adjusts itself to suit conditions and, with reasonable caution, it is an easy matter to apply the tire so that the flap will stay in its correct position. The loose endless flap was then improved by splitting,

��notching the ends in such a manner as to make the flap adjustable in circum- ference to accommodate variations in the circumference of the tire.

��A Window Ventilator Which Eliminates Drafts

IT is often inconvenient or unwise to open a window from the bottom for ventila- tion, on account of the disagreeable draft created. The illustration shows a simple method of eliminating the draft while still securing a plentiful supply of air. It is especially recommended for the sick-room or for a bedroom.

For each window, cut two pieces of 24-in. board as shown. These should be mounted

���A glass set on a slope to direct the air cur- refits upward as they enter the room

on either side of the window and fastened to the casement or sill. A groove at 60 deg. angle is cut in the board for inserting a piece of glass, the length of the window and about 6^2 i n - high. This allows the air to enter the room at an upward slant instead of directly. — J. C. Grindell.

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