Plant Suspension System with Weight Compensation
An apparatus meant to be incorporated into a suspension system suspending a plant (i.e., an overall plant that includes a physical plant and possibly a load that the physical plant supports) of a vehicle acts to alter the spring constant of at least one spring of the suspension system in response to changes in the weight of the plant so that a resonant frequency of the at least one spring isolating the plant from a jolt encountered by the vehicle during travel remains substantially unchanged despite changes to the weight of the plant.
1 . An apparatus comprising:
a suspension system coupled to a portion of a vehicle and isolating a plant of the vehicle from a jolt encountered by the vehicle during travel; and
a first spring incorporated into the suspension system to isolate the plant from at least a portion of the jolt along a substantially horizontal axis through movement along the substantially horizontal axis at a predetermined resonant frequency, wherein the first spring has a variable spring constant that changes in response to changes in weight of the plant to substantially maintain the predetermined resonant frequency.
2 . The apparatus of claim 1 , wherein the plant comprises a seat of the vehicle.
3 . The apparatus of claim 1 , wherein the first spring is a type of spring selected from a group of types of springs consisting of a gas spring, a hydraulic spring and a spring employing a combination of gas and fluid.
4 . The apparatus of claim 3 , further comprising:
a second spring incorporated into the suspension system to isolate the plant from at least a portion of the jolt along a substantially vertical axis;
a first linkage coupling the first and second springs to enable a flow of a substance therebetween wherein the substance has a physical state selected from a group of physical states consisting of a gas, a liquid and a combination of a gas and a liquid; and
a first damper incorporated into the first linkage and acting as a low pass filter to substantially permit a change in pressure of the substance in the second spring that corresponds to a change in weight of the plant to be transferred to the first spring to adjust the spring constant of the first spring, and substantially preventing a change in pressure of the substance in the second spring that corresponds to the second spring isolating the plant from the jolt from being transferred to the first spring.
5 . The apparatus of claim 4 , further comprising a valve to alter the pressure of the substance within the second spring to adjust a height of the plant relative to the portion of the vehicle.
6 . The apparatus of claim 4 , further comprising:
a third spring incorporated into the suspension system, acting at least partially in opposition to the second spring, and having a variable spring constant that changes in response to changes in weight of the plant to cooperate with the first spring to substantially maintain the predetermined resonant frequency;
a second linkage coupling the third and second springs to enable a flow of the substance therebetween; and
a second damper incorporated into the second linkage and acting as a low pass filter to substantially permit a change in pressure of the substance in the second spring that corresponds to a change in weight of the plant to be transferred to the third spring to adjust the spring constant of the third spring, and substantially preventing a change in pressure of the substance in the second spring that corresponds to the second spring isolating the plant from the jolt from being transferred to the third spring.
7 . The apparatus of claim 6 , further comprising:
a third linkage coupling the first and third springs to enable a flow of the substance therebetween; and
a third damper incorporated into the third linkage.
8 . The apparatus of claim 7 , wherein the first and third springs are implemented in a combined form in which the first and third springs both act along the substantially horizontal axis, and wherein the third linkage and the third damper are implemented as a passage formed between a chamber of the first spring and a chamber of the third spring.
9 . The apparatus of claim 1 , wherein the first spring is a mechanical spring.
10 . The apparatus of claim 9 , further comprising:
a second spring incorporated into the suspension system to isolate the plant from at least a portion of the jolt along a substantially vertical axis;
a linkage coupling the first and second springs to transfer torque therebetween; and
a damper incorporated into the first linkage and acting as a low pass filter to substantially permit a change in torque that corresponds to a change in weight of the plant to be transferred from the second spring to the first spring to adjust the spring constant of the first spring, and substantially preventing a change in torque that corresponds to the second spring isolating the plant from the jolt from being transferred from the second spring to the first spring.
11 . The apparatus of claim 10 , further comprising a third spring incorporated into the suspension system, acting at least partially in opposition to the second spring and having a variable spring constant that changes in response to changes in weight of the plant to cooperate with the first spring to substantially maintain the predetermined resonant frequency, and wherein the linkage couples the first and third springs to transfer torque therebetween.
12 . A method comprising adjusting a spring constant of a first spring of a plant suspension system of a vehicle encountering a jolt during travel in response to changes in weight of the plant to substantially maintain a predetermined resonant frequency of movement in isolating the plant from at least a portion of the jolt along a substantially horizontal axis.
13 . The method of claim 12 , further comprises linking the first spring to a second spring isolating the plant from at least a portion of the jolt along a substantially vertical axis to enable a substance having a physical state selected from the group consisting of a gas, a liquid and a combination of a gas and a liquid to flow therebetween, wherein the pressure of the substance within the second spring changes in response to changes in weight of the plant.
14 . The method of claim 13 , further comprising altering the pressure of the substance within the second spring to adjust a height of the plant relative to the portion of the vehicle.
15 . The method of claim 13 , further comprising dampening the flow of the substance between the first and second springs to substantially permit a change in pressure of the substance in the second spring that corresponds to a change in weight of the plant to be transferred to the first spring to adjust the spring constant of the first spring, and substantially preventing a change in pressure of the substance in the second spring that corresponds to the second spring isolating the plant from the jolt from being transferred to the first spring.
16 . The method of claim 15 , further comprises:
linking the second spring to a third spring acting at least partially in opposition to the first spring to enable the substance to flow therebetween;
adjusting a spring constant of the third spring in response to changes in weight of the plant to cooperate with the first spring to maintain the predetermined resonant frequency; and
dampening the flow of the substance between the second and third springs to substantially permit a change in pressure of the substance in the second spring that corresponds to a change in weight of the plant to be transferred to the third spring to adjust the spring constant of the third spring, and substantially preventing a change in pressure of the substance in the second spring that corresponds to the second spring isolating the plant from the jolt from being transferred to the third spring.
17 . The method of claim 16 , further comprises:
linking the first spring to the third spring to enable the substance to flow therebetween; and
dampening the flow of the substance between the first and third springs.
18 . The method of claim 12 , further comprises linking the first spring to a second spring isolating the plant from at least a portion of the jolt along a substantially vertical axis to enable torque to be transferred therebetween, wherein the torque transmitted by the second spring changes in response to changes in weight of the plant.
19 . The method of claim 18 , further comprising dampening the transfer of torque between the first and second springs to substantially permit a change in torque to be transferred from the second spring to the first spring that corresponds to a change in weight of the plant, and substantially preventing a change in torque from being transferred from the second spring to the first spring that corresponds to the second spring isolating the plant from the jolt.
20 . The method of claim 19 , further comprises:
linking the second spring to a third spring acting at least partially in opposition to the first spring to enable a transfer of torque therebetween;
adjusting a spring constant of the third spring in response to changes in weight of the plant to cooperate with the first spring to maintain the predetermined resonant frequency; and
dampening the transfer of torque among the first, second and third springs flow of the substance between the second and third springs to substantially permit a change in torque to be transferred from the second spring to the first and third springs that corresponds to a change in weight of the plant, and substantially preventing a change in torque from being transferred from the second spring to the first and third springs that corresponds to the second spring isolating the plant from the jolt.