| 摘要 |
PURPOSE:To certainly lock all of connection parts by one operation and to support a headrest at an accurate position, by operating a fluid pressure supply means by the operation of a lever and simultaneously tightening respective joint parts by the action of an operating fluid due to the fluid pressure supply means. CONSTITUTION:A rod 28 pushes a piston 27 by pushing an operating lever 29 toward the first arm 10 and the operating fluid in a cylinder chamber 26 is pressurized and the pressure thereof is transmitted to connection parts through respective operating fluid passages 34, 23, 21, 36, 41. Hereupon, a press ring 20 is pushed at the base end part of the first arm 10 to press the base end side part 18 of the cotter part 14 of the base end part of the first arm 10. By this pressing action, the base end side part 18 acts so as to reduce the gap of the cotter part 14 and the base end part of the first arm 10 tightens a fixing frame 2 and the revolution thereof is prevented. A press ring 35 is pressed at the connection part of the first arm 10 and the second arm 11 to closely bring the first arm into contact with the second arm 11 and a press ring 40 is pressed at the connection part of the second arm 11 and the third arm 12 to closely bring the third arm 12 into contact with the second arm 11. |
