IL103220A - Hydraulic equipment having safety control - Google Patents

Hydraulic equipment having safety control

Info

Publication number
IL103220A
IL103220A IL10322092A IL10322092A IL103220A IL 103220 A IL103220 A IL 103220A IL 10322092 A IL10322092 A IL 10322092A IL 10322092 A IL10322092 A IL 10322092A IL 103220 A IL103220 A IL 103220A
Authority
IL
Israel
Prior art keywords
hydraulic
piston
return line
equipment
chamber
Prior art date
Application number
IL10322092A
Other languages
Hebrew (he)
Other versions
IL103220A0 (en
Original Assignee
Messier Bugatti
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Messier Bugatti filed Critical Messier Bugatti
Publication of IL103220A0 publication Critical patent/IL103220A0/en
Publication of IL103220A publication Critical patent/IL103220A/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/54—Nozzles having means for reversing jet thrust
    • F02K1/76—Control or regulation of thrust reversers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7052—Single-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
    • F15B2211/8636—Circuit failure, e.g. valve or hose failure

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Combustion & Propulsion (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)

Description

HYDRAULIC EQUIPMENT HAVING SAFETY CONTROL nnoan mpa » iN n iim A B S T R A C T Hydraulic equipment comprising a body (8), a piston (9) slidably mounted inside the body and urged towards a rest position by a resilient member (11), the piston (9) co-operating with the body (8) to delimit an actuating chamber (12) opposing the resilient member (11) and connected to an outlet orifice (6) of a control valve (4) for connecting the outlet orifice (6) either to a feed line (3) or else to a return line (7), the equipment including a safety chamber (13) for putting the equipment into a rest position, said chamber being connected to the return line ( 7 ) and communicating with a face of the piston (9) facing away from the actuating chamber (12) and having an active area (14) greater than the active area (15) of the piston facing the actuating chamber (12). 1 HYDRAULIC EQUIPMENT HAVING SAFETY CONTROL The present invention relates to hydraulic equipment having safety control.
The hydraulic circuits used for feeding hydraulic equipment, in particular on board aircraft, generally include a storage tank for hydraulic liquid having a pump connected thereto for pressurizing the hydraulic liquid so as to deliver hydraulic liquid under pressure to a feed line for a set of hydraulic equipments connected in parallel between said feed line and a return line which is connected to the tank of hydraulic liquid, and which is normally maintained at a low pressure. Should one of the hydraulic equipments, or a control valve for one of the hydraulic equipments be faulty, there is a risk of a temporary hydraulic short circuit through said equipment, i.e. the feed pressure may temporarily be transmitted to the return line of the hydraulic circuit.
In addition, certain hydraulic equipments are controlled by control valves of the kind having an outlet orifice connected to an equipment-actuating chamber, the control valve being configured to connect its outlet orifice either to the feed line or else to the return line as a function of the state of the control valve, which state is determined either by an electrical command or by manual actuation. In normal operation, the actuating chamber of a hydraulic equipment is pressurized when its control valve is in a state corresponding to the feed line being connected with the outlet orifice of the control valve, and the actuating chamber is at low pressure when its control valve provides a connection between the outlet orifice and the return line. However, in the event of a temporary rise in pressure on the return line, this excess pressure is transmitted to the actuating chamber of the hydraulic equipment and therefore actuates the equipment in untimely manner.
Such a risk cannot be accepted, in particular when the hydraulic equipment is used for controlling the position of a member whose untimely actuation will have severe consequences. This applies in particular to the actuators for controlling the thrust-reversing flaps of aircraft jets.
An object of the present invention is to provide hydraulic equipment including a safety control that eliminates this kind of risk.
To achieve this object, the present invention provides a hydraulic equipment comprising a body, a piston slidably mounted inside the body and urged towards a rest position by a resilient member, the piston co-operating with the body to delimit an actuating chamber opposing the resilient member and connected to an outlet orifice of a control valve for connecting the outlet orifice either to a feed line or else to a return line, the equipment including a safety chamber for putting the equipment into a rest position, said chamber being connected to the return line and communicating with a face oC the piston facing away from the actuating chamber and having an active area greater than the active area of the piston facing the actuating chamber.
Thus, when the actuating chamber of the hydraulic equipment is connected to the return line, the resultant of the forces acting on the piston tends always to maintain it in its rest position regardless of the pressure in the return line.
The invention will be better understood on reading the following description of a non-limiting particular embodiment of the invention described with reference to the sole accompanying figure which is a diagram of a hydraulic actuator shown in axial section and in association with a hydraulic circuit.
With reference to the drawing and in the conventional manner, the hydraulic circuit comprises a tank of hydraulic liquid 1 that is normally maintained at low pressure and associated with a hydraulic pump 2 whose high pressure outlet is connected to a feed line 3 serving a set of control valves 4 for controlling hydraulic feed to respective hydraulic equipments 5, only one of which is shown in the figure. To this end, each control valve 4 includes an outlet orifice 6 which, depending on the state of the control valve 4, is connected either to the feed line 3 as shown by a solid line arrow in the figure, or else to a return line 7 via a return 3 connection represented by a dashed line arrow in the figure. The return line 7 is connected to the tank of hydraulic liquid 1. It may be observed that if one of the control valves 4 is faulty and establishes a hydraulic short circuit between the feed line 3 and the return line 7, then the high pressure of the feed line is transmitted to the return line 7 until the corresponding control valve has been taken out of circuit.
This rise in pressure is normally damped by maintaining the hydraulic tank 1 at a low pressure. Nevertheless, if a control valve for another equipment is connected to the return line 7 at a point that is closer to the faulty control valve than the hydraulic tank 1, then the corresponding hydraulic equipment will be actuated. In particular, in the accompanying figure, the hydraulic equipment 5 is a hydraulic actuator comprising a body 8 in which a piston 9 is slidably mounted and is associated with a piston rod 10. The piston 9 is normally urged towards a rest position by a resilient member constituted by a spring 11. In association with the body 8 , the piston 9 delimits an actuating chamber 12 opposing the spring 11 and connected to the outlet orifice 6 of the control valve 4 with which is it associated.
In accordance with the invention, the hydraulic equipment 5 also includes a rest position safety chamber 13 connected to the return line 7. The safety chamber 13 is in communication with a face 14 of the piston 9 facing away from the actuating chamber 12. The active area 14 of the piston 9 facing the safety chamber 13 is greater than the active area 15 of the piston 9 facing the actuating chamber 12.
Thus, when a high pressure accidentally occurs in the return line 7 while the control valve 4 is in a position that connects the outlet orifice 6 to the return line 7 , then this excess pressure is transmitted to both faces of the piston 9 , and because of the difference between their active areas, the piston 9 is maintained in its rest position as shown in the figure.
Naturally, the invention is not limited to the embodiment shown and variants may be applied thereto without going beyond 4 the ambit of the invention. In particular, although only one hydraulic equipment is shown in the figure, a plurality of hydraulic equipments may be made in accordance with the invention, with the safety chamber of each of the hydraulic equipments being connected to the return line 7.
Similarly, although the hydraulic equipment shown is an actuator, the invention is also applicable to a hydraulic distributor fitted with a sliding or a rotary actuating piston.

Claims (1)

- 5 - 103,220/2 CLAIM: f
1. Hydraulic equipment comprising a body, a piston slidably mounted Inside the body and urged towards an end-stroke rest position by a resilient member, the piston co-operating with the body to delimit an actuating chamber opposing the resilient member and connected to an outlet orifice of a control val e for connecting the outlet orifice either to a feed line or else to a return line, wherein the equipment includes a safety chamber for putting the equipment into said end-stroke rest position in case of accidental excess pressure occurring in said return line, said safety chamber being continuously connected to said return line and communicating with a face of the piston facing away from the actuating chamber and having an active area greater than the active area of the piston facing the actuating chamber.
IL10322092A 1991-09-25 1992-09-18 Hydraulic equipment having safety control IL103220A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR9111811A FR2681652A1 (en) 1991-09-25 1991-09-25 HYDRAULIC EQUIPMENT WITH SAFETY CONTROL.

Publications (2)

Publication Number Publication Date
IL103220A0 IL103220A0 (en) 1993-02-21
IL103220A true IL103220A (en) 1994-07-31

Family

ID=9417287

Family Applications (1)

Application Number Title Priority Date Filing Date
IL10322092A IL103220A (en) 1991-09-25 1992-09-18 Hydraulic equipment having safety control

Country Status (5)

Country Link
EP (1) EP0534834A1 (en)
JP (1) JPH05196010A (en)
BR (1) BR9203708A (en)
FR (1) FR2681652A1 (en)
IL (1) IL103220A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0221108D0 (en) * 2002-09-12 2002-10-23 Lucas Industries Ltd Thrust reverser for a jet engine and hydraulic actuator

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3133475A (en) * 1960-11-22 1964-05-19 Gen Electric Hydraulically-actuated operating mechanism for an electric circuit breaker
CH524076A (en) * 1970-05-21 1972-06-15 Sulzer Ag Safety circuit
JPH0415305A (en) * 1990-05-08 1992-01-20 Katsuya Mizui Piston cylinder device

Also Published As

Publication number Publication date
FR2681652B1 (en) 1995-02-10
FR2681652A1 (en) 1993-03-26
BR9203708A (en) 1993-04-20
JPH05196010A (en) 1993-08-06
IL103220A0 (en) 1993-02-21
EP0534834A1 (en) 1993-03-31

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