Such as best seen in FIG 2 {HEAD ~ the transition} between {TAIL ~ convex surface} 16 and the area confined by the surfaces 1 a, 1 b, 1 c is formed by an upwardly inclined planar surface 17, which should be inclined 30° 55° relatively to the neutral plane P 
between
Such as best seen in FIG 2 { HEAD ~ the transition } between { TAIL ~ convex surface } 16 and the area confined by the surfaces 1 a , 1 b , 1 c is formed by an upwardly inclined planar surface 17 , which should be inclined 30 ° 55 ° relatively to the neutral plane P
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