An apparatus includes at least two disk spring washers, at least one ring-shaped outer spacer coupled to the outer edges of one or two of the disk spring washers, and at least one ring-shaped inner spacer coupled to the inner edges of one or two of the disk spring washers. The apparatus also includes a central shaft concentric with the disk spring washers, the outer spacers, and the inner spacers. The apparatus also includes a bottom attachment portion coupled to the bottom of the central shaft to support the at least two disk spring washers, and a top attachment portion configured to slide vertically along the central shaft. The top attachment portion is configured to, with an application of a downward force, compress the at least two disk spring washers.

An apparatus includes a vibration isolator which incorporates at least two disk spring washers. Each disk spring washer has at least one ring-shaped outer spacer coupled to the outer edges of one or two of the disk spring washers, and at least one ring-shaped inner spacer coupled to the inner edges of one or two of the disk spring washers. A bottom attachment portion supports the disk spring washers, and a top attachment portion, with an application of a downward preload force, compresses the disk spring washers. A compression fixture applies and holds the preload force to the top attachment portion, and a second top attachment portion, with application of an additional downward force, further compresses the at least two disk spring washers.

In the spring mechanism, the negative spring mechanism biasing the loading plate to the positive side in the z-direction has the spring shaft and interspring. The spring shaft is rotatably connected to the fixed part and is connected through the slider with respect to the loading plate so that it can rotate and can move in the x-direction. The connection part with the loading plate is positioned on the positive side in the z-direction and on the positive side in the x-direction relative to the connection part with the fixed part. An elastic force countering the compression is generated by the spring shaft. The interspring is connected to the loading plate and is connected through the slider to the spring shaft. It generates an elastic force countering the displacement to the positive side in the x-direction of the connection part of the spring shaft with the loading plate.

A rotating machine system include a rotating machine. The rotating machine system can include a housing. The housing can include an inner surface. The housing can surround at least a portion of the rotating machine. The inner surface of the housing can be spaced from the rotating machine such that a space is defined therebetween. The rotating machine system can include a plurality of vibration isolators. The vibration isolators can be positioned in the space and can be operatively connected to the rotating machine and to the inner surface of the housing. The vibration isolators can be compression-type vibration isolators.

The present invention discloses a quasi-zero-stiffness (QZS) based six-degree-of-freedom (6-DOF) absolute displacement and attitude measurement device. A lower end coil and an upper end coil are respectively charged with currents in the opposite directions; The electromagnetic field and the magnetic fields of an upper magnet and a lower magnet per se are mutually acted to produce an electromagnetic stiffness opposite to the stiffness of a spring. The stiffness of the whole leg is close to zero stiffness. When the to-be-measured platform generates space motion, the reference platform is in the stationary state. At this point, the deformation amounts of the six legs can be measured by laser displacement sensors. The six deformation amounts are respectively inputted into the displacement and attitude resolver, and by forward kinematic solution of the 6-DOF device, the displacement and the attitude of the to-be-measured platform can be obtained.

In the spring mechanism, the negative spring mechanism biasing the loading plate to the positive side in the z-direction has the spring shaft and interspring. The spring shaft is rotatably connected to the fixed part and is connected through the slider with respect to the loading plate so that it can rotate and can move in the x-direction. The connection part with the loading plate is positioned on the positive side in the z-direction and on the positive side in the x-direction relative to the connection part with the fixed part. An elastic force countering the compression is generated by the spring shaft. The interspring is connected to the loading plate and is connected through the slider to the spring shaft. It generates an elastic force countering the displacement to the positive side in the x-direction of the connection part of the spring shaft with the loading plate.

A dual rate spring system is disclosed. The dual rate spring system can include a first spring and a spring coupler that have different spring rates. The dual rate spring system can include a two piece crossover ring, a two piece spring coupler, or both. The two piece crossover ring can include a first damper. The two piece spring coupler can include a second damper. The first and second damper can reduce a noise or harshness of jolt associated with a transition from the first spring to the second spring.