| 摘要 |
A door closer of simple structure has a stationary shaft (10) and a cylindrical housing (20) secured to a door. The housing (20) has therein a nonrotatable piston (80), an inner communicating passage (83) with a check valve (84) that communicates between a high-pressure oil chamber (81) and a low-pressure oil chamber (82) at the opposite sides of the piston (80), an outer communicating passage (102 and 104) that passes oil from the high-pressure oil chamber (81) toward the low-pressure oil chamber (82) when the piston (80) is displaced from the low-pressure oil chamber (82) side toward the high-pressure oil chamber (81) side, a high-pressure side cam member (91), and a low-pressure side cam member (96). When the housing (20) is rotated by the door being opened, the high-pressure side cam member (91) pushes out the piston (80) from the high-pressure oil chamber (81) side toward the low-pressure oil chamber (82) side. When the door is rotated in a door-closing direction, the low-pressure side cam member (96) pushes out the piston (80) from the low-pressure oil chamber (82) side toward the high-pressure oil chamber (81) side. |
