IMPROVEMENTS RELATING TO SUPPORT SYSTEMS FOR THE SEATED HUMAN BODY

1284650 Chairs BRITISH RAILWAYS BOARD 19 April 1971 [22 April 1970] 19285/70 Addition to 1257927 Heading A4J In a seat according to the parent Specification, comprising a flexible web mounted under tension in a supporting frame, the back-supporting length of the web includes a forwardly-projecting portion arranged to support the upper pelviclumbar region of an occupant and is constrained below the projecting portion by a transverse member of the frame, to tension it longitudinally. The web may be extended to form a seat portion. In the form shown, a tubular-metal frame formed of side members 13, 14 and cross-bars 15, 16, 17 enters pockets 4, 5 formed at the ends of a single length of netting to form head-rest and seat-front portions, the ends of the netting being attached to bars 6, 7 of the frame. The middle part of the netting is secured to parts 8 of a sub-frame, to form the forward projection, and passes behind a bar 9 forming part of the sub-frame; the bar 9 is curved to shape the netting above it. The subframe is pivoted to the main frame members 13, 14 on an axis 19 so that it can be forced against the netting to tension it; it may be held in the required position by springing behind the members 13, 14 or by any other means such as a screwthreaded adjusting mechanism. In a modification, Fig. 4 (not shown), the frame parts 8 are rigid with the members 13, 14 and the tensioning bar 9 is separate from the frame and is mounted on a pair of arms pivoted to these members at about the middle of the seat. Instead of the back and seat being formed of a single length of netting, they may be two independent lengths Fig. 2 (not shown), the back being anchored to a bar such as 9 and the seat to an adjacent bar on the frame. The latter bar may then be carried on arms pivoted at about the middle of the seat; the back portion of the netting may be attached to a bar carried on short pivoted arms projecting rearwardly from the main frame members, or may pass round a bar fixed at a position rearwardly of the main frame and be attached to a bar fixed at the base of the back-supporting part of the frame. The side frame members 13, 14 may be shaped for mounting on a separate base, which may carry a row of seats. The bars to which ends of the netting are attached may fit into hems formed in the netting, and additional hems may be provided for adjustment; alternatively, they may be fixed to the bars and the latter rotated on their own axes for adjustment. In another form u