| 摘要 |
PURPOSE:To provide a steplessly adjusting device without play by inserting an engaging projection having the tip projecting from a guide hole into a slant cam slot and providing an operating member for laterally moving the engaging projection to said engaging projection. CONSTITUTION:A horizontal cylindrical tube 4 for guide is fixedly secured to the pillar 1 side inserted in a back rest seat. A rotary cylinder 6 fixed to the head rest skeleton frame 21 side is inserted into said tube 4. The rotary cylinder 6 is formed on the outer periphery with a guide hole 5 in the bus direction, and said tube 4 is formed on the outer peripheral surface with a slant cam slot 7 into which an engaging projection 11 having the tip projecting from the guide hole 5 is inserted. An operating member is provided in the engaging projection 11 to laterally shift the engaging projection 11. Thus, when the engaging projection 11 is laterally moved by the operating member, the engaging projection 11 pushes the slant cam slot 7 in the rotary cylinder 6 to rotate the same steplessly without any play so that the front and rear position or oscillating position of the head rest can be steplessly adjusted. |
