Abstract: In an endothermic engine there are two dynamic balancing shafts driven in rotation in respectively opposite directions, at a speed twice that of the rate of rotation of the crankshaft. The dynamic balancing shafts are driven by a toothed belt transmission (1), comprising a driving pulley (2) keyed on the crankshaft, two driven pulleys (3, 4) keyed on the balancing shafts and a tensioning pulley (5) rotatably engaged with the base. The pulleys (2, 3, 4, 5) are connected together by a belt (6) having an internal (9) and external (10) toothing with a toothing pitch (P) equal to 7.5 mm, and provided with a resistant insert (7) formed by glass fibre cords (8) having a diameter equal to 0.9 mm.

Abstract: In an endothermic engine there are two dynamic balancing shafts driven in rotation in respectively opposite directions, at a speed twice that of the rate of rotation of the crankshaft. The dynamic balancing shafts are driven by a toothed belt transmission (1), comprising a driving pulley (2) keyed on the crankshaft, two driven pulleys (3, 4) keyed on the balancing shafts and a tensioning pulley (5) rotatably engaged with the base. The pulleys (2, 3, 4, 5) are connected together by a belt (6) having an internal (9) and external (10) toothing with a toothing pitch (P) equal to 7.5 mm, and provided with a reinforcing structure (7) formed by glass fibre cords (8) having a diameter equal to 0.9 mm.

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: An apparatus for handling a plurality of driving belts 2 disposed close to each other and hanging from a horizontal supporting bar 4 carried by a handling support 3 in a loading station 10. The belts are laterally engaged, from opposite sides, between two first dragging elements 26 adapted to be simultaneous moved close to each other from opposite sides relative to the belts 2. The belts 2 are elastically deformed by the dragging elements and thereby take a configuration having two vertically aligned loops 38, 39 widening in a direction away from the dragging elements 26. The dragging elements 26 are trained around respective idler pulleys 27, 28, 31 operable for causing the displacement of the belts 2 and the selective transferring of the belts to second dragging elements 42 that will convey the belts to different work stations 5, 5aa according to a predetermined sequence.

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 method and apparatus for carrying out the checking of the state of wear of a covering fabric in a driving belt (2) mounted on a plurality of pulleys (3, 4, 5) by measuring the electric resistance variations of the belt fabric. The apparatus provides that at least two of the pulleys (3, 4, 5) should be electrically insulated with respect to each other and connected to an electric circuit (20) designed to apply an electric voltage to said pulleys in order to carry out the measuring of the electric resistance of the fabric exhibited by belt stretches (A, B) comprised between the pulleys themselves. The electric resistance thus found lends itself to be compared with predetermined resistance values corresponding to different states of wear of the belt (2) fabric. The work surface of the belt (2) is coated with an electrically conductive fabric (12) acting by contact on the pulleys (3, 4, 5) and having characteristics of tensile strength.

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: Installation for the automated manufacture of transmission belts, having equipment for the preparation of a multi-belt sleeve including at least one coiling machine (SP) on toothed drum, a calendering machine (CL1) for the application of a rubber composition, a molding and curing station (V1) and a final station (FN) having at least one checking machine (CQ) connected to a central control unit (UCC). The checking process is based on the use of a narrow range of tolerance wherein the values of the magnitude under control are acceptable, and of a wider range of tolerance external to the previous one, wherein the values of the magnitude are acceptable in a conditional manner, for example, in relation to the time of permanence within such range, and in any case after a final verification of the product affected by the anomaly.

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 method and apparatus for carrying out the checking of the state of wear of a covering fabric in a driving belt (2) mounted on a plurality of pulleys (3, 4, 5) by measuring the electric resistance variations of the belt fabric. The apparatus provides that at least two of the pulleys (3, 4, 5) should be electrically insulated with respect to each other and connected to an electric circuit (20) designed to apply an electric voltage to said pulleys in order to carry out the measuring of the electric resistance of the fabric exhibited by belt stretches (A, B) comprised between the pulleys themselves. The electric resistance thus found lends itself to be compared with predetermined resistance values corresponding to different states of wear of the belt (2) fabric. The work surface of the belt (2) is coated with an electrically conductive fabric (12) acting by contact on the pulleys (3, 4, 5) and having characteristics of tensile strength.

Abstract: A toothed belt (1) having between its teeth (7) and the grooves (8) adjacent to the said teeth curvilinear connection segments (17) whose ends are located on the end of the tooth flank and the base line delimiting the grooves. The first end (18) of the curvilinear connection segment coincides with the first terminal point of an arc (20) tangent to the end of the flank and to the base line delimiting the grooves, the second end (19) of the curvilinear segment being located between the second point (21) of the said arc and the point of intersection (22) of the central axis of the groove L-L and the base line. Preferably, the toothed belt forms part of a transmission member including pulleys in which at least one of the pulleys is provided with teeth (24) filleted laterally with respect to the adjacent grooves (23) by curvilinear segments (31, 32) shaped to correspond to the curvilinear connection segments of the belt.

Abstract: A toothed belt having between its teeth and the grooves adjacent to the teeth curvilinear connection segments whose ends are located on the end of the tooth flank and the base line delimiting the grooves. The first end of the curvilinear connection segment coincides with the first terminal point of an arc tangent to the end of the flank and to the base line delimiting the grooves, the second end of the curvilinear segment being located between the second point of the arc and the point of intersection of the central axis of the grooves and the base line.

Abstract: A tensioning device is provided for a flexible belt wound around the pulleys of a drive mechanism. The tensioning device includes an elastic biasing element and a damping mechanism. The biasing element applies a force on the belt in a predetermined direction to oppose belt slackenings. The damping mechanism dampens movements of the belt. The biasing element and the damping mechanism constitute a single unit wherein both exert on the belt forces which act on the belt at the same time in a predetermined direction to maintain a predetermined tensioning. The biasing element acts independently of the damping mechanism in the presence of considerable slackenings of the belt and functions as part of the damping mechanism to dampen thrusts of the belt acting on the device in the direction opposite to the predetermined direction. A connection unit connects the damping mechanism to the biasing element.

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: 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.

Abstract: A toothed-belt and toothed-pulleys transmission including means for widening the teeth of the toothed-belt, said means corresponding to the top of each belt tooth and the base of each toothed-pulley groove.

Abstract: A toothed belt constituted by an annular body of elastomeric material, having a structure that is resistant to tensile stress embedded therein and having a toothing on one of its faces. The teeth of said annular body have at least one slot corresponding to their own top.

Abstract: A toothed-belt and toothed-pulleys transmission including means for widening the teeth of the toothed-belt, said means corresponding to the top of each belt tooth and the base of each toothed-pulley groove.