Moreover, selection of the diameter of the rod (screw) considers the durability of the ball-screw converter and the stability of the screw. The structure of the spherical head is determined by the latch and the mechanism to release it during disengagement, and the construction of the contact and linkage sensors. The latches should be activated at small forces (tens of newtons), and in shock absorption (after linkage) and docking they should withstand significant loads (10-20 kN). Rotation type latches are preferred because they are distinguished by lower friction and more simple interaction with the release mechanism. Moreover, it is relatively easy to add an additional element to the rotating type latch mechanism to insure that they are recessed in partial jamming. This circumstance is very important since the latches, along with some other elements of the rod head are difficult or even impossible to fully protect from foreign particles and contaminants. To reduce the number of elements and simplify the schematic of the contact sensor (contact sensor 1) the lobes of the head should be jointed together by conical gears. Contact sensor 2 and the linkage sensor are duplicated and have two independent pressure elements each. Jamming of the linkage sensor may prevent linkage; thus, here it is desirable to provide for recession of the lever when the sensor jams. Elements of the head (latches and release mechanism, sensors, etc.) should work in a wider range of temperatures than other units of the docking mechanism. Taking this into consideration, as well as the relatively small number of actuations, the surfaces of the latches, sensors and other parts of the head that rub are covered with solid anti-friction coatings. To transmit electrical signals from the sensors of the head of the rod to the hull of the docking mechanism an electrical muitistrand cable is used which is in the form of a long spring inside a screw. This structure is well configured, and as practice has shown, operates reliably. The equalization levers are kinematically connected to the rod. In the combined docking mechanism (Figure 3.8) they are installed on the hull, linked together by conical gears, and actuated by a cam mechanism which rotates synchronously with the nut of the ball-screw converter of the drive. The cam
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