Belts – Timing belts – With trapezoidal profile of the tooth, with metric pitch
The most common belts, practically in all industrial fields.
The angle formed by the intersection of the side faces is 40ᵒ.
The maximum allowed peripheral speed is 30 m/s.
The symbolization is done by indicating the large base (possibly the height of the trapezoid) followed by the inner length Li or the literal symbol followed by the length Li measured in inches.