Adjustable passenger seating arrangement

In an adjustable seating system, allowing variation inthe spacing between adjacent rows of passenger seats, e.g. in an aircraft, for use in a passenger vehicle, each row (14, 16, 18) is mounted on a longitudinal seat rail (30) secured to the floor. The seat rail (30) has a series of equally spaced openings (34) along its length for retaining the seating units (14, 16, 18) at any selected lengthwise location. Alternate rows (16) have seat adjustment means comprising a plunger (60, 144) for engaging in said rail (30) mounted for vertical movement between a rail-engaging position in which it engages with the rail (30) to restrain fore and aft movement and a release position in which it permits fore and aft movement of the seating unit (16), a foot (84, 156) for engaging in said rail (30) so as to resist both fore and aft movement and vertical movement, a lever (86, 158) pivotally mounted on the foot (84, 156) and having a cam follower (88, 160) engaging in vertically extending guide means (90, 162) secured to the seating unit (16), and coupling means (64, 132) responsive to displacement of the cam follower (88, 160) from the bottom of the guide means (90, 162) to move the plunger (60, 144) to its release position and adapted to return the plunger (60, 144) to its engaged position when the cam follower (88, 160) returns to the bottom of the guide means (90, 162).