Active seat suspension control system

Claim 2

An active seat suspension control system comprising the combination of: a vibrometer having a vertically movable mass therein and operative to provide a signal representing the vertical position of the mass; a seat; means for providing a signal representing the vertical position of the seat; an electrical bridge circuit coupled to receive the signal representing the vertical position of the mass and the signal representing the vertical position of the seat and operative to provide a signal representing the difference between the signals; means for adjusting the height of the seat in accordance with the signal representing the difference; and means for disabling the means for adjusting the height of the seat when the mass of the vibrometer reaches either of an opposite pair of predetermined limits of vertical position of the mass.

Claim 3

The invention set forth in claim 1, further comprising a source of power and a vehicle ignition switch coupling the source of power to the means for disabling, the means for disabling being operative to disable the means for adjusting the height of the seat when the ignition switch is turned off.

Claim 4

The invention set forth in claim 1, wherein the means for disabling includes an electrical circuit coupled to disable the means for adjusting the height of the seat when opened and a pair of switches coupled in the circuit, either of the pair of switches opening the circuit when the mass of the vibrometer reaches an associated one of the opposite pair of predetermined limits of vertical position of the mass.

Claim 5

The invention set forth in claim 3, further comprising a source of power, a vehicle ignition switch and means coupling the source of power to the electrical circuit through the ignition switch, the means for adjusting the height of the seat being disabled when the ignition switch is turned off.

Claim 6

The invention set forth in claim 3, further including a relay having contacts coupled in the electrical circuit, the relay being responsive to the opening of the electrical circuit to hold the electrical circuit open until reset and a manually actuable reset switch coupled to reset the relay.

Claim 7

The invention set forth in claim 5, further including a gain control coupled to the bridge circuit and capable of varying the sensitivity of the bridge circuit and means for setting the gain control for minimum sensitivity in response to actuation of the reset switch.

Claim 8

The invention set forth in claim 1, wherein the means for adjusting the height of the seat includes a cylinder coupled to the seat and having an opposite pair of inputs and means for applying pressurized fluid to one of the pair of inputs of the cylinder in accordance with the value of the signal representing the difference, and wherein the means for disabling includes a shutoff valve coupled to the two inputs of the cylinder and operative to couple the two inputs of the cylinder together when the mass of the vibrometer reaches either of the opposite pair of predetermined limits of vertical position of the mass.

Claim 9

The invention set forth in claim 7, wherein the means for disabling includes a coil coupled to disable the shutoff valve when energized, an electrical circuit coupled to energize the coil when closed and a pair of switches coupled in the electrical circuit, each of the pair of switches opening the electrical circuit when the mass of the vibrometer reaches one of the opposite pair of predetermined limits of vertical position.

Claim 10

The invention set forth in claim 1, wherein the vibrometer comprises the combination of: an elongated rod; means for securing the rod to a reference at one end thereof; an arm coupled to and extending generally laterally from the opposite end of the rod from the one end; a weight; means for suspending the weight from a portion of the arm opposite the rod; and means for providing a signal representing the vertical position of the weight.

Claim 11

The invention set forth in claim 9, wherein the means for securing the rod to a reference at one end thereof is adjustable relative to an axis of elongation of the rod to initially dispose the rod in a generally horizontal position.

Claim 12

The invention set forth in claim 9, wherein the means for providing a signal comprises a potentiometer having a wiper arm coupled to the opposite end of the rod.

Claim 13

The invention set forth in claim 9, further including a housing containing the arm and the opposite end of the rod, the housing including at least one bearing for rotatably mounting the opposite end of the rod, and a generally vertically disposed tube extending downwardly from the housing and containing the weight therein.

Claim 14

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; means for providing an indication of vertical position of the seat in accordance with upward and downward forces on the control system, the means comprising a vibrometer having a vertically movable mass therein and operative to provide a signal representing the vertical position of the mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the signal representing the vertical position of the mass; means responsive to the outputs of the first and second potentiometers for adjusting the vertical position of the seat in accordance with the difference between the outputs; a source of potential coupled to one of the opposite pair of circuit legs; and a variable resistor coupled between the source of potential and the other one of the opposite pair of circuit legs, the variable resistor defining a variable gain control which enables the responsiveness of the control system to be varied.

Claim 15

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; means for providing an indication of vertical position of the seat in accordance with upward and downward forces on the control system, the means comprising a vibrometer having a vertically movable mass therein and operative to provide a signal representing the vertical position of the mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the signal representing the vertical position of the mass; means responsive to the outputs of the first and second potentiometers for adjusting the vertical position of the seat in accordance with the difference between the outputs; a source of potential coupled to one of the opposite pair of circuit legs; and a variable resistor coupled between the source of potential and the other one of the opposite pair of circuit legs, the variable resistor defining a variable gain control which enables the responsiveness of the control system to be varied.

Claim 16

The invention set forth in claim 13, further including means for disabling the means for adjusting the vertical position of the seat upon the occurrence of at least one predetermined condition, means for resetting the means for adjusting the vertical position of the seat following the disabling thereof in response to a reset command, and means responsive to each resetting of the means for adjusting the vertical position of the seat for adjusting the variable resistor to a minimum gain position.

Claim 17

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; means for providing an indication of vertical position of the seat in accordance with upward and downward forces on the control system, the means comprising a vibrometer having a vertically movable mass therein and operative to provide a signal representing the vertical position of the mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the signal representing the vertical position of the mass; means responsive to the outputs of the first and second potentiometers for adjusting the vertical position of the seat in accordance with the difference between the outputs; a source of potential coupled between the opposite pair of circuit legs; a pair of variable resistors, each being coupled in a different one of the opposite pair of circuit legs between the source of potential and the first potentiometer; and means for varying the pair of variable resistors together in substantially equal amounts and in the same direction relative to the first potentiometer to vary the stiffness of vertical movement of the seat.

Claim 18

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; means for providing an indication of vertical position of the seat in accordance with upward and downward forces on the control system, the means comprising a vibrometer having a vertically movable mass therein and operative to provide a signal representing the vertical position of the mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the signal representing the vertical position of the mass; means responsive to the outputs of the first and second potentiometers for adjusting the vertical position of the seat in accordance with the difference between the outputs; a source of potential coupled between the opposite pair of circuit legs; a pair of variable resistors, each being coupled in a different one of the opposite pair of circuit legs between the source of potential and the first potentiometer; and means for varying the pair of variable resistors together in substantially equal amounts and in the same direction relative to the first potentiometer to vary the stiffness of vertical movement of the seat.

Claim 19

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; means for providing an indication of vertical position of the seat in accordance with upward and downward forces on the control system, the means comprising a vibrometer having a vertically movable mass therein and operative to provide a signal representing the vertical position of the mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the signal representing the vertical position of the mass; means responsive to the outputs of the first and second potentiometers for adjusting the vertical position of the seat in accordance with the difference between the outputs; a source of potential coupled between the opposite pair of circuit legs; and a variable resistor coupled in one of the opposite pair of circuit legs between the source of potential and the first potentiometer, the variable resistor being variable in value to provide initial adjustment of the height of the seat.

Claim 20

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; means for providing an indication of vertical position of the seat in accordance with upward and downward forces on the control system, the means comprising a vibrometer having a vertically movable mass therein and operative to provide a signal representing the vertical position of the mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the signal representing the vertical position of the mass; means responsive to the outputs of the first and second potentiometers for adjusting the vertical position of the seat in accordance with the difference between the outputs; a source of potential coupled between the opposite pair of circuit legs; and a variable resistor coupled in one of the opposite pair of circuit legs between the source of potential and the first potentiometer, the variable resistor being variable in value to provide initial adjustment of the height of the seat.

Claim 21

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; a vibrometer having a suspended mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the suspended mass; a source of potential coupled between the opposite pair of circuit legs; a differential amplifier having inputs coupled to the outputs of the first and second potentiometers and an output; an electro-hydraulic valve coupled to the output of the differential amplifier and having a pair of outputs; an emergency shutoff valve having a coil; a double ended cylinder coupled to the seat and having a pair of inputs, each of which is coupled to a different one of the pair of outputs of the electro-hydraulic valve through the emergency shutoff valve; a relay having a coil and contacts defining first and second switches; a source of power; means for coupling the source of power to the coil of the shutoff valve through the first switch of the relay; a terminal; a pair of pressure sensitive switches mounted at opposite limits of vertical movement of the suspended mass; means for coupling the pair of pressure sensitive switches in series between the source of power and the terminal; means for coupling the terminal to the coil of the relay through the second switch of the relay; a reset switch; and means coupling the terminal to the coil of the relay through the reset switch.

Claim 22

An active seat suspension control system comprising the combination of: an opposite pair of circuit legs; a seat; a first potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the seat; a vibrometer having a suspended mass; a second potentiometer coupled between the opposite pair of circuit legs and having a wiper arm providing an output which varies with the vertical position of the suspended mass; a source of potential coupled between the opposite pair of circuit legs; a differential amplifier having inputs coupled to the outputs of the first and second potentiometers and an output; an electro-hydraulic valve coupled to the output of the differential amplifier and having a pair of outputs; an emergency shutoff valve having a coil; a double ended cylinder coupled to the seat and having a pair of inputs, each of which is coupled to a different one of the pair of outputs of the electro-hydraulic valve through the emergency shutoff valve; a relay having a coil and contacts defining first and second switches; a source of power; means for coupling the source of power to the coil of the shutoff valve through the first switch of the relay; a terminal; a pair of pressure sensitive switches mounted at opposite limits of vertical movement of the suspended mass; means for coupling the pair of pressure sensitive switches in series between the source of power and the terminal; means for coupling the terminal to the coil of the relay through the second switch of the relay; a reset switch; and means coupling the terminal to the coil of the relay through the reset switch.

Claim 23

The invention set forth in claim 17, further including a variable resistor coupled between the source of potential and one of the opposite pair of circuit legs and means for adjusting the variable resistor to a condition of maximum resistance between the source of potential and said one of the opposite pair of circuit legs in response to each closure of the reset switch.

Claim 24

The invention set forth in claim 17, further including a first variable resistor coupled in one of the opposite pair of circuit legs between the first potentiometer and the source of potential, second and third variable resistors coupled in series in the other one of the opposite pair of circuit legs between the first potentiometer and the source of potential, and means for simultaneously making substantially equal adjustments to the first and the second variable resistors.

Claim 25

The invention set forth in claim 17, wherein the vibrometer includes an elongated rod, means for securing the rod to a reference at one end thereof, an arm coupled to and extending generally laterally from the opposite end of the rod from the one end, and wherein the mass is suspended from a portion of the arm opposite the rod.

Claim 26

A vibrometer comprising the combination of: an elongated rod; means for securing the rod to a reference at one end thereof; an arm coupled to and extending generally laterally from the opposite end of the rod from the one end; a weight; means for suspending the weight from a portion of the arm opposite the rod; means for providing a signal representing the vertical position of the weight; a housing containing the arm and the opposite end of the rod, the housing including at least one bearing for rotatably mounting the opposite end of the rod; and a generally vertically disposed tube extending downwardly from the housing and containing the weight therein; the end of the arm opposite the rod being in the shape of an arc of a circle and having a groove therein and the weight being suspended from the arm by a length of cable attached to an upper portion of the arm opposite the rod and at least partially residing within the groove.

Claim 27

A vibrometer comprising the combination of: an elongated rod; means for securing the rod to a reference at one end thereof; an arm coupled to and extending generally laterally from the opposite end of the rod from the one end; a weight; means for suspending the weight from a portion of the arm opposite the rod; means for providing a signal representing the vertical position of the weight; a housing containing the arm and the opposite end of the rod, the housing including at least one bearing for rotatably mounting the opposite end of the rod; and a generally vertically disposed tube extending downwardly from the housing and containing the weight therein; the end of the arm opposite the rod being in the shape of an arc of a circle and having a groove therein and the weight being suspended from the arm by a length of cable attached to an upper portion of the arm opposite the rod and at least partially residing within the groove.