Manually operated metering valve for a fuel control
First Claim
1. In a fuel management system having a primary metering valve and a secondary metering valve through which fuel from a source is supplied to an engine to meet a fuel flow requirement in response to an operational signal applied to a power lever, a transfer valve connected to the power lever for shifting from the primary metering valve to the secondary metering valve on movement of the power lever should a malfunction occur in the primary metering valve, the improvement comprising:
- sensor means for detecting the malfunction to establish a transfer signal;
control means responsive to said transfer signal for automatically transferring the fuel flow requirement from the primary metering valve to the secondary metering valve without moving the power lever when the fuel flow requirement is below a fixed level;
a first cam connected to said power lever, said first cam having an operational surface with a first constant rise from a starting point;
a second cam connected to said control means, said second cam having an operational surface with a constant drop from a starting point;
linkage for connecting the first and second cams to provide said control means with an operational input corresponding with the fuel flow requirement;
said control means includes a plunger having a cylindrical body with a first end and a second end, said first end having a stem extending therefrom, said cylindrical body having an annular groove located between the first and second ends, said first end being connected to receive said transfer signal and said second end being connected to a reference signal andfirst resilient means connected to said cylindrical body for urging said first end toward a first seat when fuel flow requirement is above the fixed level, said second cam engaging said stem to hold the first end away from the seat when the fuel flow requirement is below the fixed level.
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Accused Products
Abstract
A fuel control having an electrically operated metering valve and a manually operated metering valve through which fuel is independently scheduled to an engine. During normal operation, the electrically operated metering valve controls the flow of fuel to the engine in response to an operator input signal. Linkage connected to a power lever supplies the manually operated metering valve with an input corresponding to the fuel flow requirement requested by the operator of the electrically operated metering valve. The manually operated metering valve is connected to the source of fuel through an electrically operated transfer valve. Should an electrical failure occur, the electrically operated transfer valve is deactivated and if the fuel flow requirement is below a fixed level, fuel flows from the source through the manually operated metering valve without moving the power lever to maintain a substantially constant engine speed.
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Citations
11 Claims
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1. In a fuel management system having a primary metering valve and a secondary metering valve through which fuel from a source is supplied to an engine to meet a fuel flow requirement in response to an operational signal applied to a power lever, a transfer valve connected to the power lever for shifting from the primary metering valve to the secondary metering valve on movement of the power lever should a malfunction occur in the primary metering valve, the improvement comprising:
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sensor means for detecting the malfunction to establish a transfer signal; control means responsive to said transfer signal for automatically transferring the fuel flow requirement from the primary metering valve to the secondary metering valve without moving the power lever when the fuel flow requirement is below a fixed level; a first cam connected to said power lever, said first cam having an operational surface with a first constant rise from a starting point; a second cam connected to said control means, said second cam having an operational surface with a constant drop from a starting point; linkage for connecting the first and second cams to provide said control means with an operational input corresponding with the fuel flow requirement; said control means includes a plunger having a cylindrical body with a first end and a second end, said first end having a stem extending therefrom, said cylindrical body having an annular groove located between the first and second ends, said first end being connected to receive said transfer signal and said second end being connected to a reference signal and first resilient means connected to said cylindrical body for urging said first end toward a first seat when fuel flow requirement is above the fixed level, said second cam engaging said stem to hold the first end away from the seat when the fuel flow requirement is below the fixed level. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a fuel control having a primary metering valve through which fuel is scheduled from a source to an engine in response to an input signal and a transfer valve for switching the scheduling of fuel to a manually operated backup metering valve on a malfunction in the primary metering valve, the improvement comprising:
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a power lever connected to the primary metering valve for scheduling fuel to an engine in response to an operator input; a first cam having a surface thereon corresponding to the fuel flow requirement of the engine over the operating range; linkage means connected to said first cam for providing said backup metering with an operational input corresponding to the operator input during operation of the primary metering valve; sensor means for detecting a malfunction in the primary metering valve to establish a transfer signal; and control means responsive to said transfer signal for automatically transferring the source of fuel from the primary metering valve to the backup metering valve when the fuel flow requirement is below a fixed level to maintain a substantially constant fuel flow to the engine without moving the power lever, said control means including a first valve having a cylindrical body located in a bore of a housing, said cylindrical body having a first area, a second area, and an annular groove, said bore having a first port connected to a reference pressure, a second port connected to said sensor means, and a third port, said reference pressure being communicated to a first area on said cylindrical body, a first resilient member for urging said second area toward a seat, and a stem connected to said cylindrical body, said linkage means engaging said stem to hold said second area away from said seat when the fuel flow requirement is below the fixed level to allow the transfer signal to be applied to said second area through said second port and move the groove on the cylindrical body into communication with said third port. - View Dependent Claims (8, 9, 10, 11)
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Specification