A seat cushion extension device is provided which can slide a seat cushion via a single spring, and has high assembly efficiency and a low weight due to a simple structure. The seat cushion extension device includes: a base having first and second rack gears provided to face each other; a cushion part provided on an upper portion of the base to move forward/backward; a locking gear part combined with a shaft extending from the cushion part to the base and having a first gear provided to be engaged with the first and second rack gears; and a manipulation part combined with the cushion part to move forward/backward between the cushion part and the first gear, and having a protruding part provided on a lower surface thereof.

Device for the height adjustment of a vehicle seat, wherein the device comprises a lower part for arranging on a vehicle, wherein the device has an upper part for arranging a vehicle seat and/or for arranging a rotary unit for a vehicle seat, wherein the lower part and the upper part are coupled together via an actuating arm, wherein the device has a damping member. The device is characterized in that the damping member is present between the upper part and the lower part, wherein the damping member is configured to alter a spacing of the upper part relative to the lower part and wherein the device comprises a spring element and the spring element is present on the device such that it acts counter to a direction of extension of the damping member.

Suspension systems and grounds maintenance vehicles incorporating the same are disclosed. The suspension system may include biasing elements or springs that may be adjusted to vary the preload and thus change the spring and dampening characteristics of the suspension system. In some embodiments, the system may include an adjustment mechanism that permits simultaneous adjustment of two springs via a single action. In other embodiments, features adapted to assist an operator with mounting/dismounting the vehicle are disclosed.

Suspension systems and grounds maintenance vehicles incorporating the same are disclosed. The suspension system may include biasing elements or springs that may be adjusted to vary the preload and thus change the spring and dampening characteristics of the suspension system. In some embodiments, the system may include an adjustment mechanism that permits simultaneous adjustment of two springs via a single action. In other embodiments, features adapted to assist an operator with mounting/dismounting the vehicle are disclosed.

Embodiments related to active vibration isolation systems for a vehicle seat, as well as their methods of use, are disclosed. In some embodiments, an active suspension system may be configured to support a seat above a floor of a vehicle. The active suspension system may include two or more actuators that may be operated cooperatively to control both the roll and heave of the vehicle seat. In some instances, these actuators may also be non-back-drivable actuators. Additionally, in some embodiments, an active suspension system may include one or more torsion springs that apply torques in parallel with associated actuators of the active suspension system to support at least a portion of the loads applied to the active suspension system during operation.

A seat cushion extension device is provided which can slide a seat cushion via a single spring, and has high assembly efficiency and a low weight due to a simple structure. The seat cushion extension device includes: a base having first and second rack gears provided to face each other; a cushion part provided on an upper portion of the base to move forward/backward; a locking gear part combined with a shaft extending from the cushion part to the base and having a first gear provided to be engaged with the first and second rack gears; and a manipulation part combined with the cushion part to move forward/backward between the cushion part and the first gear, and having a protruding part provided on a lower surface thereof.

To make it possible to improve seated person's posture stability with respect to input vibration, and more improve a vibration absorption characteristic or an impact absorption characteristic caused by impact vibration as compared with conventional ones. A suspension mechanism 1 has a structure in which two suspension units 100, 200 which support a movable support part 140 and a seat support part 240 through link mechanisms 110, 120 respectively are arranged in two upper and lower stages, and a configuration such that, when the movable support part 140 and the seat support part 240 move up and down relatively in response to input vibration, the two link mechanisms 110, 210 supporting the respective parts are operated to rotate in opposite directions to each other. Therefore, a position of a hip point of a person seated on a seat supported by the seat support part 240 is displaced in an approximately vertical trajectory, which reduces forward and backward swinging and stabilizes a seating posture, resulting in good ride comfort, as compared with a case of one link mechanism.

A damper is provided on an upper frame which is a main vibrating body supported on upper portions of front links and rear links of a frame link mechanism, so as to be a sub-vibrating body which generates vibration whose behavior is different from that of vibration of the upper frame caused by the rotary motion of the front links and the rear links. When the upper frame is vibrated by input vibration, since the damper exhibits the different vibration behavior, energy of the input vibration not only is distributed as vibrational energy of the upper frame and heat energy generated by the elongation and contraction of the damper but also is consumed as energy which vibrates the damper itself provided as the vibrating body. Such arrangement and configuration of the damper improve basic performance of vibration absorbency and impact absorbency of the suspension and achieves a reduction in thickness.

Embodiments related to active vibration isolation systems for a vehicle seat, as well as their methods of use, are disclosed. In some embodiments, an active suspension system may be configured to support a seat above a floor of a vehicle. The active suspension system may include two or more actuators that may be operated cooperatively to control both the roll and heave of the vehicle seat. In some instances, these actuators may also be non-back-drivable actuators. Additionally, in some embodiments, an active suspension system may include one or more torsion springs that apply torques in parallel with associated actuators of the active suspension system to support at least a portion of the loads applied to the active suspension system during operation.

A seat support mechanism including a lifter, and configured to perform a cushion frame suspension function no matter to what height a cushion frame is adjusted. Torsion bars extending in the width direction of a cushion frame and elastically supporting the cushion frame are supported by a link mechanism disposed between sliders and the cushion frame. Even if the attitude of the link mechanism is displaced when the lifter adjusts the height, the positions of the torsion bars are displaced so as to follow the displacement. The torsion bars elastically support the cushion frame no matter to what height the torsion bars are displaced. Thus, no matter to what height the cushion frame is adjusted, the torsion bars are able to support the cushion frame with predetermined elasticity and to exhibit predetermined vibration absorption characteristics.