Industrie Pirelli S.p.a.

Mario Cicognani

Giorgio Tangorra

Vincenzo Macchiarulo

Bruno Mirabelli

Gianfranco Cimatti

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.

Toothed-pulley for transmission with a toothed-belt

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.

Toothed belt

Toothed-belt and toothed-pulley transmission

The present invention relates to a toothed belt provided with an undulated fabric embedded in the part of the belt's body between its tension resistant insert member and its back. The elastomeric material of the toothed belt disposed between the undulated fabric and the back has a lesser hardness than that forming the remaining part of the belt.

An endless flexible, elastomeric or plastic power transmission belt has a series of outwardly projecting, longitudinally spaced teeth having bases integral with the belt body and an opposite free end for meshing with teeth of a pulley. The free end of each tooth is smaller in longitudinal dimension than the base and the surfaces facing adjacent teeth of the series are curved outwardly toward the adjacent teeth. The curvature is defined by the trigonometric tangent of the angles between a straight line tangent to the curvature and a straight line parallel to the base. The trigonometric tangent increases linearly from the free end of the tooth towards the base according to a constant coefficient that is a function of the mechanical characteristics of the material from which the belt is made and the dimensions of the tooth.

A drive belt adapted for use in a continuous speed variator has an elongated annular body member reinforced with inextensible cords which are embedded along the longitudinal axis of the body member. A series of teeth is disposed along one side of the body member and rigid wedge-shaped members connected to the teeth have a trapezoidal cross-section perpendicular to the plane of symmetry of the body member.

Trapezoidal driving belt

A power transmission belt has an elastomeric body which is frusto-triangularly shaped in cross-section. Such power transmission belts are commonly referred to as V-shaped belts. The belt provided by the invention has a plurality of laterally spaced cords which are parallel to each other and are arranged longitudinally throughout the length of the belt. At least those portions of the sides or flanks of the belt which bear against the walls of grooves of a pulley wheel when the belt is rotated are covered with an elastomeric composition having cut lengths of fibrous material embedded therein and disposed so the longitudinal axes of the fibers are substantially perpendicular to the longitudinal plane of symmetry of the belt. The fibers may be impregnated with an organic polyisocyanate solution.

V-belt

A toothed belt adapted to be used while wet with a mineral oil has a ring of elastomeric material for a body, a tension resistant member inserted in the body, teeth on at least one side of the body, a rigid covering which is substantially non-deformable under flexion stresses for the teeth and intermediate groove surfaces made by doubling a rubberized fabric over an elastomeric layer as described in U.S. Pat. No. 3,937,094. The body, the teeth and rubberized fabric are all made from an oil resistant elastomer such as an epichlorohydrin rubber composition.

Oil resistant toothed belt

A tension resistant structure for driving belts and driving belts containing the tension resistant structure are provided. The tensioning structure comprises laterally spaced cords which extend substantially parallel to the longitudinal axis of the belt, the cords contain only seven threads of the polyamide, polyester or rayon with at least six of the threads being helically twisted together and disposed concentrically about the longitudinal axis of the cord, the physical characteristics of the cords are such that p (1 + K) = Rd wherein p is the pitch of the spiral of each thread; d is the diameter of the thread; R is between 27.4 and 35.1 and K is 0 to 0.03 when the thread is rayon; 0.01 to 0.07 if the thread is polyester; and 0.01 to 0.1 if the thread is polyamide.

Tension resistant structure for driving belts and the like

A reinforced plastic or elastomeric drive belt having tooth-like protuberances for meshing with the teeth of a pulley is provided with a fabric covering over the toothed surface which is more rigid and more resistant to flection stresses than the body of the belt.

A mold for shaping a belt having teeth on opposite sides thereof has a hollow cylindrical mandrel with a surface configuration corresponding to alternate grooves and teeth to be formed on one side of the belt and a plurality of bars arranged side by side around the mandrel having surfaces facing the mandrel corresponding to the configuration of teeth and grooves to be formed on the opposite side of the belt. The bars are supported in radially spaced relation with the mandrel surface in slots in the peripheral surface of end members for the cylinder and are adapted to move under pressure radially inwardly.

Growing community of inventors

Milan, Italy

Mario Cicognani