Link 1, turning in fixed guide b of part 3, has a threaded shank a. The tapered portion of link 1 fits into a corresponding tapered hole of link 2 which slides along fixed guide d of part 3. There is certain clearance c between the tapered elements of links 1 and 2 . When link 1 is turned (screwing it into part 3), link 2 is moved upward and its T-shaped shank e clamps part 4 to part 3.
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