Patent ID: 7954599

Claim:
A gear mechanism comprising: at least two toothed parts accommodated in a casing, each of the at least two toothed parts being attached to a rotating shaft in bearings joined to the casing; a storage tank that stores oil to be injected into each meshing zone of the at least two toothed parts; means for conveying the oil from the storage tank to each meshing zone to inject the oil into each meshing zone at a pressure greater than the pressure prevailing in the casing; means for reducing an internal pressure in the casing to a pressure below atmospheric pressure; and means for draining the oil to the storage tank, the draining means including: a first receptacle built into the casing for recovering the oil; a second receptacle that communicates with the first receptacle via a communication means into which the oil can flow from the first receptacle, the second receptacle in turn communicating with the storage tank; and a transfer means that is a power pump assembly controlled by an oil level in the second receptacle disposed downstream of the second receptacle and upstream of the storage tank, wherein the first and second receptacles and the storage tank are configured so that the oil can flow into them successively by gravity flow, with a substantially identical pressure prevailing in the first and second receptacles while the storage tank is generally maintained at atmospheric pressure, and means for operating the mechanism at atmospheric pressure is provided so that, if the means for reducing internal pressure in the casing fails, operation of the mechanism at atmospheric pressure is ensured.