ORTHOPEDIC APPARATUS FOR OSTEOSYNTHESIS Russian patent published in 2008 - IPC A61B17/66 F16H25/22 F16H1/34 

FIELD: medicine.

SUBSTANCE: using screw-and-nut transmission, which is a part of the apparatus, ensures resolution enhancement, increases susceptibility of the drive provided its small size and mass. The apparatus contains a mobile ring and a fixed one, self-contained electric supply, work management microcomputer, the main and two more linear actuators. Self-contained electric supply presents a small size accumulator. The main and two others linear actuators consist of microprocessor control system and drive powers, subsystem of emergency shut - down of the above mentioned drives by the patient in the form of two buttons, frame, stock, stepping micro motor, microprocessor subsystem of registration of axial force of the drives with the help of sensors on stocks, intermediate planetary reducing gear unit of 2k-h type. Sun gear of the above said reducing gear is fixed on the spindle of the stepping micro motor, described below, self-holding screw-and-nut transmission with threaded rollers, on the input end of the male screw of which carrier of the reducing gear is fixed. Sliding nut is made integral with the stock. The frame of the main drive is fully-fixed in the immobile ring with the help of the free - attitude hinge with adjustable holders of its angular position against the immobile ring of the apparatus. The stock of the main drive is connected to the bridge by a two - axis hinge , whereat three rams are fully-fixed in corresponding guiding lines, and on the other side there are three fully-fixed threaded rods. Guiding lines are connected with the frame of the main drive by a two - axis hinge. Three threaded rods through the second bridge are attached by a one-axis hinge to the mobile ring of the apparatus._{Frames of the two other drives are connected by two-axis hinge with the immobile ring of the apparatus. Stocks of the other drives through the threaded rod are connected by two - axis hinge with the mobile ring of the apparatus. Stocks in all three drives are fastened to prevent rotation against their frames. Nut-and-screw transmission with threaded rollers consists of a male screw, threaded rollers, sliding and stop nuts. Male screw is made with tooth ring, threaded sliding part and a stopping part having two - stage cylindrical surface. One stage of two-stage cylindrical surface has diameter not exceeding internal diameter of the threaded sliding part of the male screw, the other stage has diameter equal to the mean diameter of the threaded sliding part of the male screw. Threaded rollers have sliding part with threads, threaded stopping part, tooth ring on the ends and cylindrical surface, diameter of which is equal to that of the thread of the sliding part of the roller. The above said one stage is placed in front of the stopping threaded part of the threaded roller, and the other above said stage mates with the above mentioned cylindrical surface of the threaded roller. Thread of the stop part of i-roller is axially off-set against the thread on the sliding part by value Δ P1=P(z30-z3)(i-l)/np, where Pis a thread pitch, z30 and z3 correspondingly numbers of thread entries on the sliding and stop nuts, np is the number of rollers, i=l,2,...,np. Thread angle on the sliding parts of the rollers is equal in size and opposite in direction to the thread angle on the sliding part of the male screw. Thread angle on the stop nut is made equal in size and direction to the thread angle of the stop part of the roller. Stop nut has tooth ring. Tooth rings of the threaded rollers mate tooth rings of the male screw and the tooth ring of the stop nut. Sliding nut is fastened to prevent rotation.}

EFFECT: ensures better quality and shorter duration of treatment, automatisation of treatment with possibility of out - patient treatment, recording values of micro - movements and corresponding values of axial efforts in the drives with given reliability, weight and size of the drives.

2 cl, 3 dwg