"FLEXIBLE COUPLING"

TECHNICAL FIELD

This invention refers to a flexible coupling used in several industrial fields to engage torque drive shafts. TECHNIQUE STATUS

Currently, there are some kinds of flexible couplings with half-ring shaped casing - a shape similar to a tire. These couplings present a continuous section, which is appropriate to meet the configuration needs of its flanges or hubs.

The effort resulting from the torque application varies in accordance with the position along the section (nearer to, or farther from the part center).

In this situation, the continuous section and the variable strength find a stress concentration in a certain position of the section.

The maximum torque of a coupling corresponds to the one that generates stresses not higher than the permissible ones for the material used in the coupling. This maximum torque supported by the coupling is thus is limited by this stress concentration. OBJECTIVE OF THE INVENTION

The objective of this invention is to provide a variation that makes possible the presence of larger and stronger sections exactly where the stress is bigger over the flexible element, thus reducing the stress on these points (2).

This invention will be better understood with the aid of the figures that follow this descriptive report, where:

Figure 1 represents a conventional flexible coupling (1 ) with matching outer and inner surfaces; Figure 2 represents a configuration of the flexible coupling (1 ), where

we can observe the outer surface with a ring-shaped casing, and the inside one does not match this shape;

Figure 3 represents a flexible coupling (1 ), where we can observe another configuration of the inner portion of the elastic element (2). MEANS TO REACH THE OBJECTIVES

Through the variation of the sections due to the inner surface of the flexible element (2), an increase in the resistance to the torque is achieved without a significant increase in the size, nor in the rigidity (torsion, radial, axial), nor in the cost of the coupling (1 ). The inner surface of the elastic element (2) of this invention is filled with the same material of the outer surface of the elastic element, and is a single compact part with a portion of it inserted into the coupling, thus dispersing the stress. The variation of the inside surface shape (2) of this elastic element varies in accordance with the torque and the stress to which the coupling is subject. Such inside surface of the elastic element (2) will have a defined shape to provide an increase of the resistance to the torque, without an increase neither in the rigidity of the elastic element or in the final cost of the coupling as a whole.

This new shape of the inner surface of the elastic element (2) will be determined in a way to reinforce its resistance in relation to the torque that the coupled equipment will generate.

Regardless the several kinds of shapes that can be given to the stresses that shall be uniformly supported, it is certain that the internal surface (2) of the elastic element will not match the outer surface of such elastic element to equalize the stresses. WAYS TO INCORPORATE THE INVENTION

The shape presented for the elastic element (2) provides an increase in the rated torque of the flexible couplings, creating a better relation between the torque and the size due to its constructive shape.

The elastic center (1 ) of this invention has an inside surface that does not match the outer one, allowing thus to equalize the stresses on the elastic element profile (2). The definition of this inner surface depends on the arrangement of the characteristics of the materials used in its manufacturing (polymers and reinforcing agents).

One of the shapes presented in this invention is the shape of a shell added to the inner surface (2) of the elastic element, and with the elastic element with a shape of an "M" viewed from the side (see fig. 2).

Another shape presented in this invention is the half-circle shape added to the inner surface (2) of the elastic element, which makes the elastic element as a whole appear as kind of mushroom viewed from the side. This elastic center (2) can be used for any kind of coupling that uses the half-ring-shaped casing. When subject to working conditions, the maximum stress tends to disfigure in its maximum diameter. As the internal base of the set has a larger profile in the middle, the strength required to cause this deformation will be higher, thus increasing the rated torque of the coupling. Still, the strengths deriving from the torque, which act on the center are absorbed by the rubber profile and dissipated uniformly to the set periphery.

It must be evident to those that know this technique that this invention can be set up in many other specific ways without moving away from the nature or scope of the invention. Specifically, one must understand that the invention can be set up in the ways described above.