EP0569211A1 - Actuator - Google Patents

Actuator Download PDF

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Publication number
EP0569211A1
EP0569211A1 EP93303449A EP93303449A EP0569211A1 EP 0569211 A1 EP0569211 A1 EP 0569211A1 EP 93303449 A EP93303449 A EP 93303449A EP 93303449 A EP93303449 A EP 93303449A EP 0569211 A1 EP0569211 A1 EP 0569211A1
Authority
EP
European Patent Office
Prior art keywords
actuator
housing
shaft
yoke frame
override
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.)
Withdrawn
Application number
EP93303449A
Other languages
German (de)
English (en)
French (fr)
Inventor
Michael Arnold Calvert
Christopher Paul Shrive
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.)
Prime Actuator Control Systems Ltd
Original Assignee
Prime Actuator Control Systems 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
Priority claimed from GB929209559A external-priority patent/GB9209559D0/en
Application filed by Prime Actuator Control Systems Ltd filed Critical Prime Actuator Control Systems Ltd
Publication of EP0569211A1 publication Critical patent/EP0569211A1/en
Withdrawn legal-status Critical Current

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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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/02—Mechanical layout characterised by the means for converting the movement of the fluid-actuated element into movement of the finally-operated member
    • F15B15/06—Mechanical layout characterised by the means for converting the movement of the fluid-actuated element into movement of the finally-operated member for mechanically converting rectilinear movement into non- rectilinear movement
    • F15B15/066—Mechanical layout characterised by the means for converting the movement of the fluid-actuated element into movement of the finally-operated member for mechanically converting rectilinear movement into non- rectilinear movement the motor being of the scotch yoke type

Definitions

  • This invention relates to an actuator and, more particularly, to a valve actuator operated by pneumatic gas or hydraulic means wherein linear motion is converted into angular motion.
  • the "scotch yoke" mechanism for converting linear force and motion by mechanical advantage to a nominal 90 degree maximum rotational force and motion has been used extensively in the valve actuator industry for many years and the present invention aims to provide an improvement of this type of valve actuator.
  • Valve actuators when powered by pressure sources are required to be manufactured with the customer selected option of a manual override device.
  • This device allows the operator to operate the valve to the required degree of rotation by direct manual means ie without the requirement of the normal external energy source. This function is achieved by various means dependent upon the size of the valve actuator torque force required.
  • a hydraulic override system comprises a hand pump capable of generating sufficient thrust to rotate the valve.
  • the system is complex, expensive to manufacture and is used where high forces are necessary.
  • Manual gearing devices provide manual force multiplication normally by a hand operated wheel connected by means of gearing to the actuator torque producing mechanism. Operation of the hand wheel thus generates rotation of the valve.
  • a jack screw override comprises a threaded jack shaft that can be fitted directly to the power cylinder of the actuator and by screwing the shaft into the actuator generates longitudinal travel of the piston giving rotation of the valve.
  • This system is available in pressurised or non pressurised versions.
  • a pressurised system comprises a permanently fitted jack screw applied to the power cylinder. This is a complex arrangement as it is possible for the operator to enter the jack screw into a pressurised cylinder.
  • the system therefore, must carry large venting/exhaust paths for the pressurised power source, or alternatively the override casings must be designed to withstand the operating pressure.
  • actuators in this environment are operated directly by gas, this gas may cause severe corrosive attacks leading to early failure of the gearing.
  • a non-pressurised system normally requires the removal of a plug from the cylinder outer end plate. Once removed, the aforementioned threaded hexagon ended or similarly configured jack screw is fitted to the correspondingly threaded boss in the cylinder end plate. Rotation of the jack screw generates valve rotation by creating a thrust to the actuator piston assembly ie directly replacing the normal pressure power source.
  • the weakness of the system is that the plug must be removed from the cylinder this is a dangerous practice and is not considered suitable or fit for this purpose.
  • the present invention aims to overcome or at least mitigate the problems associated with the known devices discussed above.
  • an actuator for converting linear motion into rotational motion comprising a pressure chamber for receiving a working fluid, an actuator housing having a longitudinal slot provided therein, a yoke frame provided within the housing, a shaft passing through the longitudinal slot into the yoke frame, a thrust pin mounted on the shaft within the yoke frame, return means for countering working fluid pressure and an override device which allows forces stored within the actuator to be released in the event of failure of the actuator.
  • the shaft is longitudinally slidable within the slot.
  • the return means comprises a spring within a spring module mounted on the housing of the actuator and operatively connected to the shaft.
  • the override device comprises a safety device wherein hooks are provided on the spring module and corresponding apertures are provided on the housing to cooperate with the hooks.
  • the override device comprises a hand wheel or a wrench drive for manual actuation of the actuator.
  • an actuator having a housing 1 which is provided with a machined longitudinal rectangular hollow section 2 therein.
  • a yoke frame 3 of a known type is slidably received within the longitudinal hollow section.
  • the yoke frame 3 may bear directly within the housing 1 or alternatively may incorporate bearings to the slide surfaces between the yoke frame 3 and the housing 1.
  • the yoke frame 3 may be formed of one or two plates as shown by the dotted lines in Figure 1.
  • a pair of shafts A, B are slidably received within the hollow rectangular section.
  • the shafts one of which is shown in Figure 1A are connected to the piston of the actuator and are moved longitudinally within the rectangular section by fluid pressure within the pressure chamber of the actuator.
  • the shafts bear in the longitudinal slot and are in contact with the bearing surfaces at all times. This ensures that the actuator is subjected to very low bearing stresses due to the relatively large area of the shafts in contact with the bearing surfaces.
  • a thrust pin 4 which is located to co-operate with the yoke arm of the yoke frame.
  • the thrust pin 4 is located in a transverse bore through the shafts A and B and may for example be a pin and block arrangement. This arrangement is the means for producing rotary output motion from the actuator.
  • a spring cartridge module 5 is joined to the actuator housing 1 by fasteners or screwed tie bars 6.
  • a screwed shaft 7 (not shown in Figure 1A) is located longitudinally at the end plate of the spring cartridge.
  • the shaft 7 may rotate but cannot travel in a longitudinal axis.
  • the shaft 7 may rotate on a low friction device such as a needle ball/bearing thrust disc or other similar low friction bearing 8.
  • the shaft 7 may be rotated externally of the plate by means of a hand wheel 9 or other type of wrench drive 10.
  • Options requiring an output thrust greater than that generated by direct manual operation will incorporate an external device such as a gear chain belt or other such device and may be operated by an input shaft with its axis either longitudinal or at any angle to the actuator longitudinal axis.
  • the override thrust and locating components may be sealed against environmental ingress by a suitable arrangement.
  • a locking device may be fitted to prevent uncontrolled rotation of the override screw.
  • the inner end of the screwed shaft 7 enters through the yoke frame 3 and screws into a second thrust nut 4', the nut being held captive to prevent rotation with the yoke frame 3.
  • the nut 4' is prevented from unscrewing off the end of the shaft 7 by a circlip, split pin 11 or roll pin.
  • the spring cartridge module 5 incorporates stored energy mainly be means of compressed springs 12 or alternatively other force imparting means could be constructed within the assembly.
  • a safety device is connected to the abutting faces of the spring cartridge module 5 and actuator housing 1.
  • the safety device comprises a retention device such that failure or removal of the retaining fasteners whilst spring force is being generated would result in the spring cartridge being retained by the safety device to the actuator housing.
  • the end face 13 of the housing 1 incorporates two or more through holes 14 which are accessible from the internal side of the housing end face.
  • the spring cartridge module front mounting plate face incorporates 2 or more hook shaped devices 15. The tip of each of the hook shaped devices 15 terminates in a spigot 16 with a diameter such that a clearance entry to the hole 14 in the actuator end face is possible.
  • the assembly of the unit permits the retaining devices to enter into the actuator housing 1 and be rotated to a position in which the retaining fasteners 14,16 are aligned. In this alignment the hook part 15 of the safety device is located with slight clearance immediately above the inner face entry of the hole 14 through the housing end face.
  • the principle of operation of the device is that for normal actuator operation ie by pressure source, the override mechanism remains in the park position, as shown in Figure 5 the device incorporating lost longitudinal motion by allowing the internal end of the rectangular thrust face of the yoke frame 3 to travel slidingly along the non rotating override screw shaft 7.
  • Rotation of the hand wheel 9, wrench drive or other rotational input device by the operator causes the override thrust nut 4' to screw up the shaft 7 abutting the inner end of the scotch yoke frame 3 and causes the actuator to rotate.
  • the device is lightweight and extremely simple to construct,. It cannot slip from engagement and there is an extremely low risk of seizure. There is no connection to any pressurized source therefore no removal of plugs is necessary and no danger to the operator should the actuator be allowed to operate by pressure source during the manual override operation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Transmission Devices (AREA)
EP93303449A 1992-05-02 1993-05-04 Actuator Withdrawn EP0569211A1 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB9209559 1992-05-02
GB929209559A GB9209559D0 (en) 1992-05-02 1992-05-02 Actuator
NO932971A NO932971L (no) 1992-05-02 1993-08-20 Aktuator for omdannelse av lineær bevegelse til rotasjonsbevegelse
CN93117081.8A CN1099854A (zh) 1992-05-02 1993-09-01 致动器
CA002108109A CA2108109A1 (en) 1992-05-02 1993-10-08 Actuator

Publications (1)

Publication Number Publication Date
EP0569211A1 true EP0569211A1 (en) 1993-11-10

Family

ID=27427093

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93303449A Withdrawn EP0569211A1 (en) 1992-05-02 1993-05-04 Actuator

Country Status (4)

Country Link
EP (1) EP0569211A1 (no)
CN (1) CN1099854A (no)
CA (1) CA2108109A1 (no)
NO (1) NO932971L (no)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10273989B2 (en) * 2014-12-01 2019-04-30 Rotork Fluid Systems S.R.L. Valve actuator device with driving arm having a modular structure

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2009328618B2 (en) * 2008-12-16 2012-12-13 Rotalin International Pty. Ltd. Linear actuator with internal linear to rotary conversion and external rotary component
CN102917904B (zh) * 2010-03-31 2016-07-06 凯毅德股份公司 用于机动车辆的致动器和锁定装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1171685B (de) * 1958-04-21 1964-06-04 Karl Adams Klappenventil mit Differentialkolben
DE6800971U (de) * 1968-10-04 1969-02-20 Waldenmaier J E H Vorrichtung zum waehlweisen handantrieb von druckmittelgesteuerten kraftkolben
US3801062A (en) * 1973-05-25 1974-04-02 Contromatics Corp Manual valve override
DE2508683A1 (de) * 1975-02-28 1976-09-09 Hitoshi Yazaki Antrieb fuer absperrorgane
EP0023120A1 (en) * 1979-07-20 1981-01-28 Rotork Controls Limited Fluid-operated actuator comprising a detachably mounted fail-safe unit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1171685B (de) * 1958-04-21 1964-06-04 Karl Adams Klappenventil mit Differentialkolben
DE6800971U (de) * 1968-10-04 1969-02-20 Waldenmaier J E H Vorrichtung zum waehlweisen handantrieb von druckmittelgesteuerten kraftkolben
US3801062A (en) * 1973-05-25 1974-04-02 Contromatics Corp Manual valve override
DE2508683A1 (de) * 1975-02-28 1976-09-09 Hitoshi Yazaki Antrieb fuer absperrorgane
EP0023120A1 (en) * 1979-07-20 1981-01-28 Rotork Controls Limited Fluid-operated actuator comprising a detachably mounted fail-safe unit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10273989B2 (en) * 2014-12-01 2019-04-30 Rotork Fluid Systems S.R.L. Valve actuator device with driving arm having a modular structure

Also Published As

Publication number Publication date
NO932971L (no) 1995-02-21
CN1099854A (zh) 1995-03-08
CA2108109A1 (en) 1995-04-09
NO932971D0 (no) 1993-08-20

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19941214

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18D Application deemed to be withdrawn

Effective date: 19961231