Link mechanism of reciprocating internal combustion engine

A link mechanism (1) of an engine includes: an upper link (4) having a first end connected to a piston pin (3) of a piston (2); a lower link (7) connected to the upper link (4) via an upper pin (10) having a center (H), the lower link (7) being connected to a crank pin (6) of a crank shaft (5: 6, 12, 13); a control shaft (8: 14, 15) extending substantially in parallel with the crank shaft (5: 6, 12, 13), the control shaft (8: 14, 15) having a rotational center (B); and a control link (9) including: a first end swingably connected to the control shaft (8: 14, 15), and a second end connected to the lower link (7). In a process of the center (H) of the upper pin (10) moving nearer to the axial line (G) of the piston pin (3), the center (J) of the control pin (11) moves in the upward direction, thus inclining the lower link (7) and allowing the center (H) of the upper pin (10) and the center (F) of the piston pin (3) to move in the downward direction. A link mechanism (1) of an engine includes: an upper link (4) having a first end connected to a piston pin (3) of a piston (2); a lower link (7) connected to the upper link (4) via an upper pin (10) having a center (H), the lower link (7) being connected to a crank pin (6) of a crank shaft (5: 6, 12, 13); a control shaft (8: 14, 15) extending substantially in parallel with the crank shaft (5: 6, 12, 13), the control shaft (8: 14, 15) having a rotational center (B); and a control link (9) including: a first end swingably connected to the control shaft (8: 14, 15), and a second end connected to the lower link (7). In a process of the center (H) of the upper pin (10) moving nearer to the axial line (G) of the piston pin (3), the center (J) of the control pin (11) moves in the upward direction, thus inclining the lower link (7) and allowing the center (H) of the upper pin (10) and the center (F) of the piston pin (3) to move in the downward direction.