Abstract: A head rest stay retaining device has an engagement face provided on the stay thereof which supports the head rest. The engagement face is formed continuously to a predetermined length along the axis thereof, and it further has a pushing member with an engagement face forced so as to be in contact with the engagement face of the stay, thereby retaining the stay, due to the engagement between these two engagement faces. In one version, the engagement face on the stay may taper inwards in a downwards direction, towards the axis of the stay; this engagement face may be knurled. The pushing member may be spring-loaded and/or with a grooved or corrugated engagement face, which may engage the tapered and/or knurled engagement face of the stay. The pushing member may be eccentrically mounted or pivoted or the like, and in a generally elliptical form or other non-circular shape or configuration.

Abstract: A seat which has a pneumatic component. The pneumatic component is pressurized to a desired degree to conform the curvature and hardness of the surface of the seat to the preference of the seat occupant. The pressurization is carried out by manipulating a control mechanism which allows air into and release air from the pneumatic component.