A seat structure having improved seat suspension means

1,003,427. Resilient seat mountings. BOSTROM CORPORATION. Aug. 18, 1962, No. 31820/62. Heading A4U. A seat structure includes a seat 10 supported on a base 34 by resilient means 22 and normally inoperative vibration damping means 36 which can be rendered operative to damp the seat vibrations by a releasable coupling which, when engaged, locks the seat 10 to the base 34 through the vibration damping means 36. The suspension system 22 comprises torsion rods 23 journalled in a rear plate 20 secured to the seat frame 12 and connected to rubber torsion springs 24 mounted on a front plate 18, the rods 23 having rigidly secured thereto crank arms 26 connected by pivoted links 28 to the base 34 The damper 36 comprises a piston 49 slidable in a cylinder 46, connected by an arm 38 and a bracket 39 to a crank arm 26, and a yoke 52 secured to the piston 49 and carrying a connection 54 having a frustroconical nose 56 which is slidable in a housing 41 mounted on an apertured plate 42. The damper 36 normally floats in the bearing 40, but when sufficient travel is imparted thereto by dovmward seat movement the nose 56 is pressed through the aperture in the plate 42 to be locked by a spring biased catch 44 engaging a groove 58 behind the nose 56. The damper 36 thus becomes operative until the nose 56 is manually released from the catch 44.