The present invention referes to a gear-type elongating element with automatic lubrication, in particular for applications on big-sized plants, to manufacture sheets, beams, iron and steel profiles or for naval, railway, mining applications, or in cement plants, pipelines, etc.

Such gear-type elongating elements are used for transmitting motion in big-sized kinematic chains, and, due to their prolonged use in dusty, hot ahd humid environments, are subjected to various problems of wear, malfunctions and the like. In order to solve such problems, the currently-used elongating elements are lubricated with various devices (for example the one known from document US-B1-5979207) and theie lubrication is performed through an enter of grease inside a chamber in which the toothing work. The grease is inserted approximately once every month, but during this period it is consumed, being transformed into heat, and therefore the chamber itself willl have a lower amount of grease and a slight depression due to its volumetric decrease, which attracts polluting agents inside it.

Object of the present invention is solving the above prior art problems, by providing a gear-type elongating element equipped with a device which allows an automatic, correct and constant lubrication for the whole working life of the elongating element and decrease the greasing interval to once every three months.

The above and other objects and advantages of the inventio, as will result from the following description, are obtained with a gear-type elongating element with automatic lubrication as claimed in claim 1. Preferred embodiments and nontrivial variations of the present inventino are the subject matter of the dependent claims.

It is intended that all enclosed claims are an integral part of the present description.

The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which:

Figure 1 is a partial side sectional view of an embodiment of the elongating element according to the present invention;

- Figure 2 is a detailed side sectional view of the elongating element of Figure 1 with its spring loaded; and

- Figure 3 is a detailed side sectional view of the elongating element of Figure 1 with its spring unloaded .

With reference to the Figure, a preferred embodiment of the present invention is shown and described. It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) can be made to what is described, without departing from the scope of the invention as appears from the enclosed claims.

According to the Figures, the elongating element 10 between two geared heads 20 of the present invention is equipped with an automatic lubrication through a system which operates in order to have a continuous lubrication of the toothing and of the thrusting parts; moreover, it creates inside the elongating element an overpressure condition with respect to the outside, preventing the external polluted agents (such as lamination water, vapours etc.) from getting in contact with the grease which lubrifies the toothing. Moreover, in case of internal overpressures, an axially placed valve exhausts the excess pressure.

With reference to the Figures, the elongating element 10 is equipped with at least one cartridge 12 composed of a cylinder 2, inside which a piston 1 equipped with seals 5, 7, slides and is actuated by thrusting means 3 (in this case a coil spring, but it could also be a gas spring or other equivalent thrusting system) .

The lubricating grease goes out of the top of the cartridge 12 through a hole 4 with an adequate diameter and computed for its necessary use, while the cartridge 12 is filled from outside through a suitable system of greasers 6.

The elongating element 10 is then preferably equipped with an over-pressure valve 8, which exhaust the excess pressure in the system.