Hydromechanical lead-lag control device

Claim 2

A control unit for a power unit having an output with a speed characteristic, means for producing a feed-back fluid flow correlated to the speed of the power unit and an input power control, comprising: a relatively stationary valve body having a first fluid chamber of one substantially uniform cross-sectional area opening into a second fluid chamber of a second smaller substantially uniform cross-sectional area; a first piston generally sealingly mounted within said first chamber to form a first expansible chamber on one side of said first piston; a second piston generally sealingly mounted within said second chamber and forming a second expansible chamber with the other side of said first piston; means drivingly interconnecting said first and second pistons for relative axial movement and for movement of said second piston in response to movement of said first piston; a fluid inlet opening into said first expansible chamber for conducting feed-back fluid; a fluid outlet from said first expansible chamber axially spaced from said fluid inlet opening; a control member selectively positionable according to desired speed; means for interconnecting said control member and said second piston with the input power control for changing the quantity of power fed to the power unit according to the positioning of said control member and according to the positioning of said second piston, whereby feed-back fluid from the power unit that is correlated in flow to the speed of the power unit will pressurize said first chamber in an amount correlated to the position of said first piston relative to said outlet for correspondingly moving said second piston and therewith the input power control through said interconnecting means.

Claim 3

The device of claim 1, wherein said means interconnecting said pistons includes a spring.

Claim 4

The device of claim 1, wherein said means interconnecting said pistons includes fluid generally confined in said second expansible chamber so that axial movement of said first piston will tend to produce a correspondingly greater axial movement of said second piston correlated to the ratio of effective cross-sectional areas of said pistons exposed to said second expansible chamber.

Claim 5

The device of claim 3, wherein one of said pistons includes fluid bleed passage means there-through so that the relative movement between pistons will be greater for high frequency oscillations of said first piston than it will be for low frequency oscillations of said first piston.

Claim 6

The device of claim 3, wherein each of said pistons includes through fluid bleed passage means so that tHe relative movement between pistons will be greater for high frequency oscillations of said first piston than it will be for low frequency oscillations of said first piston.

Claim 7

The device of claim 1, including means biasing said second piston relative to said body toward said first piston.

Claim 8

The device of claim 1, wherein said means for interconnecting said second piston and said control member with the input power control includes a lever having three spaced pivot points, with one of said pivot points drivingly connected to said control member, a second pivot point drivingly connected to said second piston and a third pivot point to be drivingly connected to the input power control.

Claim 9

The device of claim 7, wherein said control member is a cam, and said lever is freely mounted only by said pivot points.

Claim 10

The device of claim 1, including a piston rod axially extending from said second piston through said first chamber and forming a part of said means for interconnecting said control member, said second piston and the input power control; said first piston being annular and surrounding said piston rod.

Claim 11

A hydromechanical lead-lag control device, for use in a power system having speed related fluid flow and a mechanical position device representing other system parameters, comprising: a. a first cylinder containing a partially restrained free piston having opposite first and second head faces each exposed to a different one of two cylinder volume spaces and fluid supply and exhaust ports in one said cylinder space for supply to and passage through said cylinder of speed related fluid flow, said ports being so located as to permit said free piston to close said exhaust port without closing said supply port; said first cylinder and free piston combination having fluid bleed passage means between said two cylinder faces to permit slow equalization of pressures; b. a second cylinder separated into a work volume space and a free space by a drive piston; an actuating rod fixed to said drive piston, said rod having remote means for attachment to a mechanical position device; said second cylinder having fluid conduit means communicating between its work volume space and the second cylinder space of said first cylinder and having port means for draining fluid from its free space; said drive piston also having mechanical biasing means for forcing said drive piston and actuating rod in a direction toward said work volume space; said second cylinder and drive piston combination having fluid bleed passage means between said work volume space and said free spring; and c. additional meachnical biasing means partially restraining said free piston by exerting equal force on the two said pistons, biasing said free piston toward said supply and exhaust ports and biasing said drive piston away from said work volume space whereby said control device will move said actuating rod more or less precipitously in response to sudden or large scale variations of speed as measured by fluid flow and relatively little in response to other variations in predetermined relationships as determined by the ratios among the piston face areas and biasing means forces.

Claim 12

A hydromechanical lead-lag control device, for use in a power system having speed related fluid flow and a mechanical position device representing other system parameters, comprising: a. a first cylinder containing a partially restrained free piston having opposite first and second head faces each exposed to a different one of two cylinder volume spaces and fluid supply and exhaust ports in one said cylinder space for supply to and passage through said cylinder of speed related fluid flow, said ports being so located as to permit said free piston to close said exhaust port without closing said supply port; said first cylinder and free piston combination having fluid bleed passage means between said two cylinder faces to permit slow equalization of pressures; b. a second cylinder separated into a work volume space and a free space by a drive piston; an actuating rod fixed to said drive piston, said rod having remote means for attachment to a mechanical position device; said second cylinder having fluid conduit means communicating between its work volume space and the second cylinder space of said first cylinder and having port means for draining fluid from its free space; said drive piston also having mechanical biasing means for forcing said drive piston and actuating rod in a direction toward said work volume space; said second cylinder and drive piston combination having fluid bleed passage means between said work volume space and said free spring; and c. additional meachnical biasing means partially restraining said free piston by exerting equal force on the two said pistons, biasing said free piston toward said supply and exhaust ports and biasing said drive piston away from said work volume space whereby said control device will move said actuating rod more or less precipitously in response to sudden or large scale variations of speed as measured by fluid flow and relatively little in response to other variations in predetermined relationships as determined by the ratios among the piston face areas and biasing means forces.

Claim 13

A hydromechanical lead-lag control device, for a power system wherein speed is represented by a fluid flow rate and other parameters by mechanical position, comprising a primary cylinder with a piston substantially responsive to sudden or large scale variations of fluid flow rate but non-responsive to flow rate variations below a predetermined level; a secondary cylinder with a piston similarly responsive to hydraulic parameters and regeneratively responsive to movements of said first piston; an actuating rod fixed to said second piston and having connecting means for attachment to said system mechanical position; said pistons being mechanically biased in opposition to increased fluid flow with said secondary piston being biased for movement relative to said cylinders and the primary piston being biased for Movement relative to the secondary piston whereby a mechanical positioning device in a system may be moved quickly to adjust other parameters to compensate for precipitous changes in speed but ignore minor deviations or gradual speed changes in accordance with criteria built into the control device.

Claim 14

A hydromechanical lead-lag control device, for a power system wherein speed is represented by a fluid flow rate and other parameters by mechanical position, comprising a primary cylinder with a piston substantially responsive to sudden or large scale variations of fluid flow rate but non-responsive to flow rate variations below a predetermined level; a secondary cylinder with a piston similarly responsive to hydraulic parameters and regeneratively responsive to movements of said first piston; an actuating rod fixed to said second piston and having connecting means for attachment to said system mechanical position; said pistons being mechanically biased in opposition to increased fluid flow with said secondary piston being biased for movement relative to said cylinders and the primary piston being biased for Movement relative to the secondary piston whereby a mechanical positioning device in a system may be moved quickly to adjust other parameters to compensate for precipitous changes in speed but ignore minor deviations or gradual speed changes in accordance with criteria built into the control device.