| 摘要 |
This invention relates to an annular braking disc in which a pair of spaced-apart braking members are connected by a first set of radial fins, each adjacent spaced-apart pair of which is integral with the opposite sides of one of a second set of radial fins, the radial length of which is less than the radial length of the first set of fins. The inner ends of a certain chosen number of fins of both sets of fins are integral one with the other and so arranged and disposed as to provide one of several arcuate segments on each of which is formed an inwardly-extending circumferentially spaced-apart securing lug. The lug that is thus formed integral with each with one of these segments is so disposed inward from each of a pair of braking faces formed on the respective opposite sides of the braking disc as to be out of contact with braking elements that may have braking engagement with these braking faces. Each lug is provided with an elongated slot for receiving a bolt whereby bolts extending through the elongated slots in these lugs secure the braking disc to an annular member pressed on a car axle. The several segments of the annular braking disc have provided between each pair of adjacent segments and each pair of adjacent lugs a radial outwardly extending slot, the length of which is less than the radial length of the braking faces and substantially equal to the length of the shorter fins whereby these slots, in cooperation with the elongated slots in the lugs, provide for both radial and arcuate thermal expansion and contraction of that portion of the annular braking disc extending between each pair of adjacent slots independently of the remaining portion of this braking disc thereby eliminating cracking of the disc by thermal expansion and contraction.
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