Abstract: The mechanical system is surrounded by a protective chamber (33) and is filled with a liquid material which is transformed in situ into a resilient material that adheres to the inside walls of the chamber and which protects the operative surfaces of the mechanical system.

Abstract: The invention relates to a safety connection for drilling purposes, especially for oil wells. The connection comprises two portions (1,2) which, during normal drilling, transmit the torque and the thrust required for the tool to operate, said torque and thrust being transmitted via a drive cone (11) and fluting (10). In the event of the tool becoming jammed downhole, strong axial traction breaks calibrated traction links (4) at a predetermined force, thereby separating said two portions (1, 2) and making it possible to abandon downhole solely the tool and the connection portion (1) connected thereto.

Abstract: The present invention relates to drilling a well with a bent bore. A bending device is inserted in a drilling string between a stabilizer and an active motor element. If the drilling string is rotated in one direction the bending device takes up a rectilinear configuration for ensuring rectilinear drilling, and if the drilling string is rotated in the opposite direction it takes up a bent configuration, thereby transforming itself into a bent coupling for curved drilling. The device comprises two superposed sleeves (1, 2) one of which is capable of rotating through a limited angle about a pivot (3) whose axis lies at the same small angle (A) to the axes (10, 10A) of both sleeves. The invention is applicable to drilling oil wells or geothermal wells.

Abstract: In a method of measuring azimuth for non-vertical drilling, during rotation of the drill pipe string two components of the magnetic field are measured continuously within a cylindrical section of the drill pipe string. This section is fabricated from the ferromagnetic steel usually employed for fabricating the drill pipes. The two components are measured by a magnetometer and lie along two axes perpendicular to the axis of the section and rotating with it. At the moment when the component of the acceleration due to gravity is maximum along one of these two axes, an accelerometer device commands the calculation and recording of the ratio of the two measured components of the magnetic field. On the basis of the value thus recorded, the measured inclination of the drill pipe string and the local inclination of the magnetic field, the azimuth of the drill pipe string relative to magnetic north is calculated.

Abstract: The device for measuring stresses applied to a drilling tool comprises a removable instrument socket (2) secured by means of protuberances (15, 16) thereon to the wall of a compartment formed thereby in a shaft (OM) such as to make fast said socket and said shaft in two transverse planes (12, 13) and as to transmit to said socket the strains occurring in the shaft in response to the stresses to be measured. Strain gauges (9) are fitted to the socket to measure said strains, and accordingly said stresses.

Abstract: A solid core (3) serves to transmit both torque and axial thrust (if any) between first and second end pieces (1 and 2) having longitudinal axes that may be up to 10.degree. out of alignment. The core is close to being cubical in shape, having two interfitting sets of three adjacent sides each comprising a first semicircular plane face, a semi-cylindrical face, and a second semicircular plane face. Concave recesses (10, 13) are provided in respective front faces of the two end pieces to receive each of the semi-cylindrical surfaces of the core. The "chunky" nature of the core maximizes the torque that can be transmitted in a given volume.

Abstract: In a turbodrill, there is no guarantee that a rotary friction ring (1) is or will remain exactly at right angles to its shaft (2). Wear against a co-operating non-rotary friction ring (6) is thus uneven, and if the surrounding medium is drilling mud, small abrasive grains can penetrate between the friction rings where they are not in contact and score them where they are in contact. The non-rotary friction ring is mounted on a moving sleeve (28) which is connected to a fixed sleeve (33). A spring (17) urges the friction rings into contact. An arrangement of balls in axial grooves between the sleeves allows the moving sleeve (28) to tilt slightly relative to the fixed sleeve (33). The non-rotary friction ring can thus wobble to keep in good contact with the rotary friction ring.

Abstract: A device preventing the unscrewing of two bodies (2, 3), and in particular of two lengths of a turbodrill, joined end-to-end in threaded union, said device comprising a blocking part (4) which immobilizes the two bodies by means of teeth. The blocking part (4) is provided with two series of teeth, one of which series engages with the teeth of one body and the other with the teeth of the other body.

Abstract: A safety device for a vehicle sliding door which detects any obstacle hindering the door closing movement and which cannot injure a passenger struck by the door. The door closing force is limited to a non dangerous value and the door comprises a tongue groove joint surrounded by a flexible lip joint. An obstacle is first struck by the flexible lips and only after retraction of these lips by the tongue. The presence of this obstacle hinders the penetration of the tongue into the groove and the closing of the door.