US3768371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic system failure detectors
Assignee: Bendix Corp
•
Filing: 1971-03-24
•
Granted: 1973-10-30
•
Expires: 1991-03-24
Abstract
Abstract Hydraulic system failure detector including a sensor in a high pressure drain line connected between possible sources of excessive pressure or flow and a drain. The sensor includes a restriction capable of passing limited flows and of relieving limited pressures. It also includes a damped, pressure-operated bypass valve in parallel with the restriction. Relief valves in branches of the high pressure drain line isolate the failure sensor from normal high pressure in those lines until the occurrence of overpressure resulting from a failure thus to permit detection of failures characterized by widely differing fluid pressures while permitting calibration of the detector at the pressure of the lowest failure pressure.
Inventors
- 👤 M Orme
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:13
CPC Classifications
F; F15; F15B; F15B20/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
221 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said actuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; supply line valve closing means for closing said supply line valve in response to said failure signal; said drain line comprising a check valve at a point between the actuator and the failure sensing means which check valve opens toward the failure sensing means said control valve including means for completing direct connection from the actuator to the drain; and means for collecting leakage fluid from said actuator and introducing it into the drain line associated therewith at a point between the check valve and the failure sensing means.
Claim 2
Dependent Claim
221 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said actuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; supply line valve closing means for closing said supply line valve in response to said failure signal; said drain line comprising a check valve at a point between the actuator and the failure sensing means which check valve opens toward the failure sensing means said control valve including means for completing direct connection from the actuator to the drain; and means for collecting leakage fluid from said actuator and introducing it into the drain line associated therewith at a point between the check valve and the failure sensing means.
Claim 3
Dependent Claim
204 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said acTuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; supply line valve closing means for closing said supply line valve in response to said failure signal; in which the drain line includes means in the form of a differential pressure relief valve upstream from the failure sensing means for discharging fluid from the actuator only when its pressure exceeds supply pressure by a given amount, the relief valve being sensitive to the difference between drain line pressure and supply line pressure.
Claim 4
Dependent Claim
204 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said acTuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; supply line valve closing means for closing said supply line valve in response to said failure signal; in which the drain line includes means in the form of a differential pressure relief valve upstream from the failure sensing means for discharging fluid from the actuator only when its pressure exceeds supply pressure by a given amount, the relief valve being sensitive to the difference between drain line pressure and supply line pressure.
Claim 5
Dependent Claim
36 words
The invention defined in claim 2 which further comprises means for collecting leakage fluid from said actuator and introducing it into the drain line at a point between the relief valve and the failure sensing means.
Claim 6
Dependent Claim
201 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said actuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; and supply line valve closing means for closing said supply line valve in response to said failure signal; and in which said failure sensing means comprises: a first spring closed, pressure responsive valve in series with the drain; a less sensitive and damped pressure opening and spring closed valve in parallel with the first valve; and means for providing said failure signal upon opening of the less sensitive valve.
Claim 7
Dependent Claim
201 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said actuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; and supply line valve closing means for closing said supply line valve in response to said failure signal; and in which said failure sensing means comprises: a first spring closed, pressure responsive valve in series with the drain; a less sensitive and damped pressure opening and spring closed valve in parallel with the first valve; and means for providing said failure signal upon opening of the less sensitive valve.
Claim 8
Dependent Claim
22 words
The invention defined in claim 4 which further comprises a check valve in the drain line upstream from said failure sensing means.
Claim 9
Dependent Claim
196 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said actuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; supply line valve closing means for closing said supply line valve in response to said failure signal; in which the supply line valve closing means of each hydraulic system is ineffective to close the supply line to its respectively associated actuator when a failure signal is provided by the respectively associated failure sensing means of the other hydraulic systems of said position control system.
Claim 10
Dependent Claim
196 words
For incorporation in a position control system of the kind in which an output element is controlled by plural hydraulic systems each of which includes an hydraulic actuator and an associated control valve for controlling hydraulic fluid flow from a pressurized source to the actuator and from the actuator to a system drain, improved failure detection and control apparatus, comprising, in each hydraulic system: a supply line valve connected in the supply line between said source and said actuator; a high pressure drain line connected between the actuator and the drain; failure sensing means in said drain line and normally closing said drain line for providing a failure signal when pressure in said drain line exceeds some preselected value and for opening said drain line when pressure therein exceeds some preselected value; supply line valve closing means for closing said supply line valve in response to said failure signal; in which the supply line valve closing means of each hydraulic system is ineffective to close the supply line to its respectively associated actuator when a failure signal is provided by the respectively associated failure sensing means of the other hydraulic systems of said position control system.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |