Abstract: The orthodontic expansion screw has two bodies, the mutual distance between which can be changed by a spindle means. The spindle has an activating part with a threaded part and is turned into a threaded hole of one of the two bodies. The bodies have a first end, which faces the activating part of the spindle, and a second end, which faces away from the activating part of the spindle. A linear guiding means engage both bodies and guide them while preventing a relative rotation of the bodies and prevent inadvertent twisting of the spindle relative to the bodies. The spindle's threaded part has a recess in which the at least one threaded part is inserted and has an extension externally that contacts the threaded part on a flattened region or in the recess, whereas it elastically presses against the threaded part.

Abstract: The present invention relates to a self-locking bolt-nut assembly including a bolt; a nut tightened on the bolt; and a washer provided between the bolt and the nut, wherein the nut has a counterbore being formed in the nut, and has a plurality of stop protrusions formed on the inner surface of the circumferential sidewall of the counterbored portion of the nut, the stop protrusions being arranged in a circumferential direction at regular intervals, the washer including the rotation-preventive protrusion protruded on inner circumference of the washer towards the center thereof, the rotation-preventive protrusion being inserted into the insertion guide groove; and a plurality of elastic protrusions which is protruded on outer circumference of the washer, being inclined in the direction where the nut is turned to tighten it.

Abstract: A present invention provides a locking mechanism capable of preventing a bolt from loosening. A bolt 5 has a head provided with a first part which comprises openings 511. A locking washer 4 is provided with a second part which includes outer projections 411 and a third part which includes insertion projections 401 on an outer edge. A taper piece 1 has a portion provided with a fourth part which comprises openings 105. The first part and the second part can engage with each other and the third part and the fourth part can engage with each other when said bolt 5 fastens at least two members 7 and 8 trough said washer 4 and said taper piece 1. Accordingly, the bolt 5 is prevented from rotating in an loosening direction.

Abstract: A heat exchanger, particularly with an integrated oil heat exchanger, has screw-in connectors. Each connector is secured to the exchanger using a retaining ring, which has finger forming projections. The heat exchanger has an annular collar with circumferentially spaced teeth on its inner circle. The fingers engage the teeth. The fingers and the teeth are arranged to prevent the connector from being unintentionally unscrewed or loosened by virtue of the connector being secured by the retaining ring.

Abstract: A locking washer arrangement which includes two (2) washer members fabricated from a hardened steel material, a thicker one on the bottom and a thinner one on the top. The top surface of the top washer member and the bottom surface of the bottom washer member preferably have a relatively high coefficient of friction and may be grooved, embossed or otherwise roughened so they will grip the surfaces they come into contact with while the bottom surface of the top washer member and the top surface of the bottom washer member have a relatively low coefficient of friction to facilitate relative movement therebetween. Relatively long flexible tabs project radially outward from the periphery of the top washer member and distal ends are bent downwardly to engage and interlock between corresponding relatively short stiff tabs projecting radially outward from the periphery of the bottom washer member.