Abstract: In a process for manufacturing toothed belts of any length, a tubular sleeve comprising a layer of cords (1) and at least a layer of elastomeric material (2) is preformed in an autoclave without being vulcanized so as to produce, on the inner surface thereof, a plurality of grooves (5) spaced apart from one another according to a predetermined toothing pitch (P). The sleeve is helically cut to obtain a continuous strip (7) to be subsequently wrapped over two wrapping drums (8, 9) suitably spaced apart from each other depending on the circumferential extension to be given to the belt. The obtained annular element (10), when the wrapping has been completed, is trued up by means of the provided grooves, between a molding matrix (11) and opposite mould (12) and is submitted to a pressing step and simultaneous cross-linking of the elastomeric material (2) by closing said elastomeric material between the molding matrix (11) and opposite mold (12) according to stages in succession.

Abstract: A driving belt (2) operatively mounted on at least a first (3a) and second (4) pulleys electrically insulated from each other, is provided with an electrically conductive covering fabric acting in contact relationship with the pulleys. By applying an electric voltage to the pulleys (3a, 4) the electric resistance value offered by the belt (2) is detected and this value is compared with a reference value to which a given degree of wear of the belt corresponds. When the detected resistance value is greater than the reference value, a danger signal is emitted. The danger signal is inhibited during the belt operation and during a predetermined waiting time starting from the moment of the belt stopping in order to avoid the resistance detection to be altered by electrostatic charges present on one of the pulleys (3a, 4) and/or the high temperature in the vicinity of the belt (2).

Abstract: In the apparatus of this invention a plurality of cylindrical matrices 2 are used to form tubular sleeves of elastomeric material to be later cured and cut into short segments to be used as belts, usually toothed belts. A coiling station 8 places a reinforcing fiber helically around the entire length of the sleeve. The matrix having the coils is then turned to a vertical position by a transfer member 28 and transferred, by means of an adjacent rotating platform 6 to a winding station 9 for application of a sheet of elastomeric material over the thread. The matrix having the completed but uncured sleeve is then placed back on the rotating platform. The coiling station and the winding station each have a tilting member 34 or 43 with two pairs of arms 39 or 52 so that while a completed matrix is swung out of the working position, a fresh matrix is swung into position.

Abstract: A toothed pulley is provided which includes a plurality of grooves alternating with a plurality of teeth. The flank of each groove is joined to the head of the adjacent tooth by a connection formed of at least two convex curvilinear segments and a recess. The curvilinear segments are tangent to the end of the flank and to the terminal point of the tooth head delimitated by the outer circumference of the pulley respectively. The pulley engages with a toothed belt which includes a connection between the tooth flank and the adjacent groove, which may be in the form of a parabolic arc.

Abstract: An elastically extensible flexible belt is provided which comprises an annular body of elastomeric material in which is embedded a plurality of elongated elements arranged along a surface corresponding to the position of the neutral axis of the belt. The belt is characterized in that each elongated element, at 1/10 of its ultimate tensile stress, has an elongation value able to balance a shrinkage value of the innermost surface of the belt, ranging between two limit values .epsilon..sub.1 .epsilon..sub.2 corresponding to the bending of the belt according to two pre-established curvatures. The first curvature is represented by a circumference whose radius r.sub.1 is equal to 60% of the radius R of the circumferential development of the annular body in correspondence of the elongated elements and the second curvature is represented by a circumference whose radius r.sub.2 corresponds to 35% of the radius R of the circumferential development of the annular body.

Abstract: A toothed belt is provided which is made of an elastomeric material or the like and which comprises a plurality of teeth, alternating with spaces, covered with at least one layer of textile material. The elastomeric material forming the top of at least one tooth and the relative covering textile material layer are shaped to define at least one depression limited by two lateral protuberances. The seam joining the textile layer end portions is situated along the depression so that no rubbing can take place between the seam and a surface external to the belt. Preferably, the depression botton is formed to have a curvilinear shape and the ratio between the thickness "s" of the covering textile material layer and the bending radius "r" of the depression bottom ranges between 0.1 and 10.0.

Abstract: A V-belt for continuous speed variators and which is formed of a visco-elastomeric material and includes a group of teeth formed on upper and lower parts thereof. The two groups of teeth are opposed to one another with each having a substantially equal base-surface. Each of said teeth is at least partially covered by a stiffening element that is oriented transverse to the belt and extends to opposite sides of the belt. Lateral surfaces of each pair of opposing teeth for contacting with corresponding pulleys are comparable in shape.

Abstract: A pulley for a synchronous drive system comprising a toothed-belt of polymeric material, the pulley comprising grooves provided with flanks having a parabolic arc-shaped profile and a bottom whose ends coincide with the vertices of said parabolic arc-shaped profile. The length of the bottom is comparable with that of the parabolic arc-shaped profiles. Preferably, the grooves have a shape determined by a hob whose rolling pitch line is tangent to the outer circumference of the pulley.