GB1583762A - Pressurised fluid actuating system - Google Patents

Pressurised fluid actuating system Download PDF

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Publication number
GB1583762A
GB1583762A GB3084676A GB3084676A GB1583762A GB 1583762 A GB1583762 A GB 1583762A GB 3084676 A GB3084676 A GB 3084676A GB 3084676 A GB3084676 A GB 3084676A GB 1583762 A GB1583762 A GB 1583762A
Authority
GB
United Kingdom
Prior art keywords
pressure
accumulator
hydraulic
tractor
control valve
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
GB3084676A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Perkins Engines Group Ltd
Original Assignee
Massey Ferguson Perkins Ltd
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 Massey Ferguson Perkins Ltd filed Critical Massey Ferguson Perkins Ltd
Priority to GB3084676A priority Critical patent/GB1583762A/en
Priority to FR7722514A priority patent/FR2359015A1/en
Priority to DE19772733189 priority patent/DE2733189A1/en
Publication of GB1583762A publication Critical patent/GB1583762A/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
    • B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
    • B60T13/142—Systems with master cylinder
    • B60T13/147—In combination with distributor valve

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Braking Systems And Boosters (AREA)
  • Regulating Braking Force (AREA)

Description

(54) PRESSURISED FLUID ACTUATING SYSTEM (71) We, MASSEY -FERGUSON- PERKINS LIMITED, 33/35 Davies Street, London W1Y 2EA, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to actuating systems operated by pressurised fluid and particularly to braking systems for trailers.
It is necessary according to the legislation of certain countries to provide a braking system for an agricultural tractor and trailer combination which enables braking effort to be applied to the trailer wheels in proportion to the braking effort applied to the tractor wheels. The effort applied to trailer braking is usually derived from the hydraulic system to the accompanying tractor and as this system is used for a number of other services such as steering, the trailer braking system must receive priority. To achieve this special valves must be provided. These are costly in themselves and it is expensive to provide for building them into a limited number of tractors destined for certain countries only.
The present invention seeks to overcome these difficulties.
According to the present invention an actuating system, suitable for use with a combination of tractor and trailer brakes, comprises an electric motor connectible to an electrical supply, a hydraulic pump drivable by said electric motor, a control valve including a spool therein connected to receive pressure fluid from said hydraulic pump, a hydraulic accumulator connected to said control valve, a muscular effort signaller so connected to said control valve as to regulate the position of the spool in the control valve, and an actuator connected to said control valve to receive pressure fluid therefrom, the arrangement being such that in a non-energised state of the signaller, the spool of the control valve is positioned so as to pass pressure fluid from the pump to the accumulator and in an energised state of the signaller the spool of the control valve is positioned so as to pass pressure fluid from the pump and from the accumulator to the actuator to pressurise the actuator to a required degree.
Preferably the actuator is a trailer brake actuator and the muscular effort signaller comprises a brake pedal and a master cylinder connected to the control valve to operate the spool through a spool actuator. Instead of a brake pedal, the signaller may comprise a hand lever.
Preferably the source of electric current supply is the battery normally carried on the tractor and the braking system may also incorporate a pressure switch sensitive to pressure in the hydraulic accumulator and adapted to stop the electric current supply to the motor on reaching a certain pressure level. Further the pressure switch may also start the electric current supply to the motor when the accumulator pressure drops to a predetermined low level, provision being made for hysteresis operation of the switch.
As a further preference the brake actuator is connected to the control valve through a hydraulic connection which includes a selfsealing coupling so that only the brake actuator is carried on the trailer, the remainder of the system being carried on the tractor.
Preferably the pump is capable of a delivery of the order of 200 cubic centimetres per minute.
The invention also provides a tractor equipped with an actuating system comprising an electric motor connected to an electric supply carried by the tractor, a hydraulic pump drivable by the electric motor, a control valve connected to receive pressure fluid from the hydraulic pump, a hydraulic accumulator connected to the control valve to receive fluid pressure therefrom, a pedal operated tractor hydraulic brake system including a master cylinder controlling operation of a spool in the control valve, the spool being operable in response to movement of the pedal to selectively pass pressure fluid from the pump to the accumulator or from the pump and the accumulator to a self-sealing coupling adapted to be connected to a pressure fluid line communicating with a hydraulic brake actuator of a trailer.
The invention will now be described by reference to the accompanying drawings of which: Figure 1 is a schematic representation of the braking system on a tractor and trailer com bination.
Figure 2 is a diagrammatic representation of the braking system.
In Figure 1 a tractor 1 is coupled to a trailer 2 each having their respective brakes 3 and 4 on their wheels 5 and 6. The tractor brake 3 is actuated by depressing a pedal 7 mechanically linked to the brake actuator cam 8 through a master cylinder 9. The tractor battery 10 is connected in an electrical circuit to an electric motor 11 which is close coupled to drive a hydraulic pump 12. The hydraulic pressure from the pump 12 is delivered to a control valve 13 which is connected to the master cylinder 9, a hydraulic accumulator 14 and the hydraulic trailer brake actuator 1 5 which is on the trailer and operates on the trailer brake 4. A selfsealing coupling 16 for use when hitching or unhitching the trailer, is placed in the line 17 which connects valve 13 and actuator 15.A switch 18, which is sensitive to accumulator pressure energises or de-energises the electrical circuit, controlling the operation of the motor 11.
Referring to the diagrammatic Figure 2, some additional details are included. The pump 12 takes up hydraulic fluid from a reservoir 20 constituted conveniently by the tractor transmission housing. The pump delivery passes through a non-return valve 21 to the valve 13 which conveniently is constituted by a spring return, pressure applied 3-port two-position spool 22 having a feathering facility. The pressure from the master cylinder 9 by means of spool actuator 23 is used to displace the spool 22 from the position shown, which is a charging condition, to the alternate position where both pump 12 and accumulator 14 are in controlled communication with the brake actuator 1 5.
The controlled communication is proportional to the effort exerted at the pedal 7 and in turn to the master cylinder 9 and spool actuator 23 pressure.
The accumulator 14 is gas filled and a double diameter hydraulic sensing cylinder 24 having a double diameter piston 26 is in permanent communication with it. When the smaller diameter of the piston 26 is exposed to pressure, the pressure will rise to a given high level in order to overcome the spring 25 and open the switch 18, whereupon the larger diameter of the piston 26 is exposed to pressure. The closure pressure for the switch will be much lower than the pressure required to open the switch. Hence, with the motor 11 and pump 12 running, when the accumulator pressure reaches the predetermined high level the switch 18 will open and the motor will stop until the lower pressure is reached in the accumulator 14 when the switch 18 will close and start the motor again for recharging the accumulator.An alternative arrangement which likewise provides hysteresis operation of the switch 18 is to provide a two rate over-centre spring mechanism, i.e. one rate in one direction and a different rate in the other direction, so that two different pressures are necessary for respectively opening and closing the switch.
The actuating system is suitable for addition to existing tractor trailer combinations and to any other application where progressive and proportional control of first and second actuators is desired. Applications of this invention in the agricultural machinery field are for bale density control and power adjustment of the lift rods on a tractor power lift. This latter application is particularly important in view of the fact that the legislation of a number of countries tends to isolate the tractor driver more and more from his controls which consequently have to become power adjustable and remotely controllable.
The pump is of such a size that its operation does not require a heavy energy drain on the normal tractor battery. - - Although the invention has been particularly described with reference to a vehicle mounted system using the vehicle's electrical supply, the invention can be applied to a system in which the electric motor is driven from a mains supply.
WHAT WE CLAIM IS: 1. An actuating system comprising an electrical motor (11) connectible to an electrical supply, a hydraulic pump (12) drivable by the electric motor (11), a control valve (13) including a spool (22) therein connected to receive pressure fluid from the hydraulic pump (12), a hydraulic accumulator (14) connected to the control valve (13), a muscular effort signaller (7, 9) so connected to the control valve as to regulate the position of the spool (22) in the control valve (13), and an actuator (15) connected to the control valve (13) to receive pressure fluid therefrom, the arrangement being such that, in a non-energised state of the signaller (9), the spool (22) of the control valve (13) is positioned so as to pass pressure fluid from the pump (12) to the accumulator (14) and in an energised state of the signaller (9), the spool (22) of the control valve (13) is positioned so as to pass pressure fluid from the pump (12) and from the accumu lator to the actuator to pressurise the actuator to a required degree.
2. An actuating system according to claim 1 in which the actuator (15) is a trailer brake actuator.
3. An actuating system according to claim 1 in which the muscular effort signaller (9) comprises a brake pedal (7) and a master cylinder connected to the control valve (13) to operate the spool (22) through a spool actuator (23).
4. An actuating system according to claim 1 in which the electrical supply is a battery (10) carried on a tractor.
5. An actuating system according to claim 1 in which a circuit carrying the electrical supply includes a switch (18) sensitive to pressure in
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    bination.
    Figure 2 is a diagrammatic representation of the braking system.
    In Figure 1 a tractor 1 is coupled to a trailer
    2 each having their respective brakes 3 and 4 on their wheels 5 and 6. The tractor brake 3 is actuated by depressing a pedal 7 mechanically linked to the brake actuator cam 8 through a master cylinder 9. The tractor battery 10 is connected in an electrical circuit to an electric motor 11 which is close coupled to drive a hydraulic pump 12. The hydraulic pressure from the pump 12 is delivered to a control valve 13 which is connected to the master cylinder 9, a hydraulic accumulator 14 and the hydraulic trailer brake actuator 1 5 which is on the trailer and operates on the trailer brake 4. A selfsealing coupling 16 for use when hitching or unhitching the trailer, is placed in the line 17 which connects valve 13 and actuator 15.A switch 18, which is sensitive to accumulator pressure energises or de-energises the electrical circuit, controlling the operation of the motor 11.
    Referring to the diagrammatic Figure 2, some additional details are included. The pump
    12 takes up hydraulic fluid from a reservoir 20 constituted conveniently by the tractor transmission housing. The pump delivery passes through a non-return valve 21 to the valve 13 which conveniently is constituted by a spring return, pressure applied 3-port two-position spool 22 having a feathering facility. The pressure from the master cylinder 9 by means of spool actuator 23 is used to displace the spool 22 from the position shown, which is a charging condition, to the alternate position where both pump 12 and accumulator 14 are in controlled communication with the brake actuator 1 5.
    The controlled communication is proportional to the effort exerted at the pedal 7 and in turn to the master cylinder 9 and spool actuator 23 pressure.
    The accumulator 14 is gas filled and a double diameter hydraulic sensing cylinder 24 having a double diameter piston 26 is in permanent communication with it. When the smaller diameter of the piston 26 is exposed to pressure, the pressure will rise to a given high level in order to overcome the spring 25 and open the switch 18, whereupon the larger diameter of the piston 26 is exposed to pressure. The closure pressure for the switch will be much lower than the pressure required to open the switch. Hence, with the motor 11 and pump 12 running, when the accumulator pressure reaches the predetermined high level the switch 18 will open and the motor will stop until the lower pressure is reached in the accumulator 14 when the switch 18 will close and start the motor again for recharging the accumulator.An alternative arrangement which likewise provides hysteresis operation of the switch 18 is to provide a two rate over-centre spring mechanism, i.e. one rate in one direction and a different rate in the other direction, so that two different pressures are necessary for respectively opening and closing the switch.
    The actuating system is suitable for addition to existing tractor trailer combinations and to any other application where progressive and proportional control of first and second actuators is desired. Applications of this invention in the agricultural machinery field are for bale density control and power adjustment of the lift rods on a tractor power lift. This latter application is particularly important in view of the fact that the legislation of a number of countries tends to isolate the tractor driver more and more from his controls which consequently have to become power adjustable and remotely controllable.
    The pump is of such a size that its operation does not require a heavy energy drain on the normal tractor battery. - - Although the invention has been particularly described with reference to a vehicle mounted system using the vehicle's electrical supply, the invention can be applied to a system in which the electric motor is driven from a mains supply.
    WHAT WE CLAIM IS: 1. An actuating system comprising an electrical motor (11) connectible to an electrical supply, a hydraulic pump (12) drivable by the electric motor (11), a control valve (13) including a spool (22) therein connected to receive pressure fluid from the hydraulic pump (12), a hydraulic accumulator (14) connected to the control valve (13), a muscular effort signaller (7, 9) so connected to the control valve as to regulate the position of the spool (22) in the control valve (13), and an actuator (15) connected to the control valve (13) to receive pressure fluid therefrom, the arrangement being such that, in a non-energised state of the signaller (9), the spool (22) of the control valve (13) is positioned so as to pass pressure fluid from the pump (12) to the accumulator (14) and in an energised state of the signaller (9), the spool (22) of the control valve (13) is positioned so as to pass pressure fluid from the pump (12) and from the accumu lator to the actuator to pressurise the actuator to a required degree.
  2. 2. An actuating system according to claim 1 in which the actuator (15) is a trailer brake actuator.
  3. 3. An actuating system according to claim 1 in which the muscular effort signaller (9) comprises a brake pedal (7) and a master cylinder connected to the control valve (13) to operate the spool (22) through a spool actuator (23).
  4. 4. An actuating system according to claim 1 in which the electrical supply is a battery (10) carried on a tractor.
  5. 5. An actuating system according to claim 1 in which a circuit carrying the electrical supply includes a switch (18) sensitive to pressure in
    the hydraulic accumulator (14) controlling operation of the motor (11).
  6. 6. An actuating system according to claim 5, in which a sensing means (24) is provided whereby the switch (18) is operable to stop the motor (11) at a given pressure in the hydraulic accumulator (14) and to start the motor (11) at a predetermined lower pressure in the hydraulic accumulator (14).
  7. 7. An actuating system according to claim 6 in which the sensing means (24) comprises a hydraulic cylinder having two portions each of a different internal diameter, and a piston (26) therein having two portions each of a different diameter, wherein the portion of the piston (26) having the smaller of the diameters is responsive to pressure in the accumulator (14) to open the switch (18) against the bias of a spring (25) and wherein the portion of the piston having the larger diameter is responsive to pressure in the accumulator (14) to permit the spring (25) to close the switch (18).
  8. 8. An actuating system according to claim 6 in which the sensing means (24) comprises an overcentre spring mechanism having a first spring rate in one direction and a second spring rate in the other direction.
  9. 9. An actuating system according to claim 1 in which the control valve (13) includes a spring return, three-port, two-position spool (22) having a feathering facility.
  10. 10. An actuating system according to claim 2 in which the trailer brake actuator (15) is connected to the control valve through a hydraulic connection which includes a selfsealing coupling (16).
  11. 11. An actuating system according to claim 10 in which the brake actuator (15) is carried on a trailer (2) the remainder of the system is carried on a tractor (1).
  12. 12. A tractor (1) equipped with an actuating system comprising an electric motor (11) connected to an electrical supply (10) carried by the tractor (1), a hydraulic pump (12) drivable by the electric motor (11), a control valve (13) connected to receive pressure fluid from the hydraulic pump (12), a hydraulic accumulator (14) connected to the control valve (13) to receive fluid pressure therefrom, a pedal operated tractor hydraulic brake system including a master cylinder (9) controlling operation of a spool (22) in the control valve, the spool (22) being operable in response to movement of the pedal (7) to selectively pass pressure fluid from the pump (12) to the accumulator (14) or from the pump (12) and the accumulator (14) to a self-sealing coupling (16) adapted to be connected to a pressure fluid line (17) communicating with a hydraulic brake actuator (15) of a trailer (2).
  13. 13. A tractor equipped with an actuating system according to claim 1 wherein the system controls adjustment of lift rods on a power lift.
  14. 14. An actuating system substantially as hereinbefore described with reference to the accompanying drawings.
GB3084676A 1976-07-23 1976-07-23 Pressurised fluid actuating system Expired GB1583762A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB3084676A GB1583762A (en) 1976-07-23 1976-07-23 Pressurised fluid actuating system
FR7722514A FR2359015A1 (en) 1976-07-23 1977-07-22 CONTROL SYSTEM ESPECIALLY FOR CONTROL OF THE BRAKES OF THE TRAILER OF A VEHICLE
DE19772733189 DE2733189A1 (en) 1976-07-23 1977-07-22 ACTUATION DEVICE, IN PARTICULAR FOR TRAILER BRAKES

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3084676A GB1583762A (en) 1976-07-23 1976-07-23 Pressurised fluid actuating system

Publications (1)

Publication Number Publication Date
GB1583762A true GB1583762A (en) 1981-02-04

Family

ID=10314057

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3084676A Expired GB1583762A (en) 1976-07-23 1976-07-23 Pressurised fluid actuating system

Country Status (3)

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DE (1) DE2733189A1 (en)
FR (1) FR2359015A1 (en)
GB (1) GB1583762A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2846067C2 (en) * 1978-10-23 1985-12-05 Fritzmeier AG, Oberentfelden Hydraulic braking system for tractors

Also Published As

Publication number Publication date
FR2359015B1 (en) 1981-04-10
FR2359015A1 (en) 1978-02-17
DE2733189A1 (en) 1978-01-26

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Legal Events

Date Code Title Description
PS Patent sealed
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee