| 摘要 |
Apparatus characterised in that it comprises: -A) a bearing surface 18 of small dimensions, -B) a feeler 2, 3, 4, in the shape of a rod, which passes through the bearing surface 18 to come into contact with the bottom of the tread to be measured, while the bearing 18 comes onto the top of the tread. -C) a display pointer 8, 9, connected to the rod 4 of the feeder 2 by an adjustable linkage means 11, 12, 14, -D) a magnifying lens 17, mounted above the graduated scale 7 and the pointer 8, 9. <IMAGE>
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