with slots although shorter than the slots on the seat cushions the bottom surface of cushions 26 28 extends for the full width of the cushions cushions 26 28 are shorter than cushions 22 24 the slots on cushions 26 cooperate with the tongue 36 39 and one half 52a of the tongue 52 the slots on cushion 28 cooperate with the other half 52b of the tongue 52 and with the tongue 36 the cushions are otherwise identical and only cushion 22 will be described in detail as shown more clearly in fig3 and 4 the cushion 22 has a rectangular frame 59 between layers of padding 58 the cushion is covered with fabric 56 the slots 54 55 are provided in parallel portions of the frame 59 along the sides thereof generally equidistant from the top and bottom surfaces of the cushion 22 a latch mechanism is provided within each of the cushions between the layers of padding 58 the latch means includes a pair of rods 60 62 each pivoted at one end to a rectangular link member 64 rod 60 has its free end extending through an elliptical hole in one leg of the rectangular frame 59 similarly the free end of rod 62 extends through an ellipitical hole in one leg of the opposite side of the frame 59 the holes in the frame 59 align the free ends of the rods 60 62 with the grooves 54 55 on opposite sides of the.