Adjustable seat for motor vehicles

Claim 2

Motor vehicle seat comprising a cushion (4), a back (2), and: support means for the seat (1) which allow an adjusting movement to be imparted to the seat in a longitudinal direction relative to the structure (P) of the motor vehicle, characterised in that: -at least partially separate support means (5, 7; 5, 6; 101, 104; 104) are provided for the cushion (4) and the back (2) so that separate adjusting movements can be imparted to the cushion (4) and the back (2) along respective translation paths, and, -the support means for the cushion (4; 5, 7; 101, 104) and the back (2; 5, 6; 104) are connected together kinematically (5) in such a way that the movement of one of the cushion (4) and the back - (2) involves the movement of the other of the cushion (4) and the back (2), and the extent of movement of the cushion (4) is a fraction of the extent of movement of the back (2).

Claim 3

Seat according to Claim 1, characterised in that the extent of movement of the cushion (4) is of the order of half the extent of movement of the back (2).

Claim 4

Seat according to Claim 1 or Claim 2, characterised in that the support means comprises at least one pivotable arm (5; 104) having one end (9; 105) hinged to the structure (P) of the motor vehicle, a free end (10; 106) for connection to the back (2, 8), and an intermediate region (11; 107) between the hinge end (9; 105)and the free end (10; 106) for connection to the cushion (4).

Claim 5

Seat according to Claim 3, characterised in that the intermediate region (11) is halfway between the hinge end (9) and the free end (10) of the at least one pivotable arm (5).

Claim 6

Seat according to any one of Claims 1 to 4, in which the cushion (4) has respective front and rear end edges (12, 13) relative to the structure (P) of the motor vehicle, characterised in that, during the adjusting movement in the forward direction relative to the structure (1) of the motor vehicle, the support means (5, 7; 101,104) for the cushion (4) impart a tilting movement to the cushion (4), which raises the rear edge (13) of the cushion (4).

Claim 7

Seat according to any one of Claims 1 to 5, characterised in that the support means (5, 6, 8) for the back (2) have a configuration such as to maintain the back (2) in a constant orientation relative to the structure (P) of the motor vehicle during the adjusting movement of the back (2).

Claim 8

Seat according to Claim 5 and Claim 6, characterised in that the support means comprise, on at least one side of the seat (1): -first (5) and second (6) pivotable arms of substantially the same length, having respective hinge ends (9, 14) connected to the structure (P) of the motor vehicle and separated by a predetermined distance,and respective free ends (10, 15) connected to the back (8, 2) and separated by a distance equal to the said predetermined distance, the first arm (5) also having an intermediate region (11) between the hinge end (9) and the free end - (10) for connection to the cushion (4) in a position between the front end edge (12) and rear end edge (13) of the cushion (4), and -a third pivotable arm (7) having a hinge end (16) connected to the structure (P) of the motor vehicle and a free end (17) connected to the cushion (4) adjacent the rear end edge (13) of the cushion (4), the third arm (7) being situated in a position intermediate the first and second arms (5, 6) and having a length from its hinge end (16) to its free end - (17) of less than the length of that portion of the first arm (5) between the hinge end (9) and the intermediate region (11) of the first arm.

Claim 9

Seat according to Claim 3 and Claim 5, characterised in that the at least one pivotable arm (104) is shaped so that the hinge end (105), the free end (106) and the intermediate region (107) are located at the vertices of a triangle,the vertex corresponding to the intermediate region (107) facing the rear of the seat (1).