GB2113764A - Rotary actuators - Google Patents

Rotary actuators Download PDF

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Publication number
GB2113764A
GB2113764A GB08234988A GB8234988A GB2113764A GB 2113764 A GB2113764 A GB 2113764A GB 08234988 A GB08234988 A GB 08234988A GB 8234988 A GB8234988 A GB 8234988A GB 2113764 A GB2113764 A GB 2113764A
Authority
GB
United Kingdom
Prior art keywords
piston
cylinder
piston rod
shaft
remote
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Withdrawn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
GB08234988A
Inventor
Brian Lawrence Smith
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.)
Angus Fire Armour Ltd
Original Assignee
Angus Fire Armour 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 Angus Fire Armour Ltd filed Critical Angus Fire Armour Ltd
Publication of GB2113764A publication Critical patent/GB2113764A/en
Withdrawn legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/02Mechanical layout characterised by the means for converting the movement of the fluid-actuated element into movement of the finally-operated member
    • F15B15/06Mechanical 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
    • F15B15/068Mechanical 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 helical type
    • AHUMAN NECESSITIES
    • A62LIFE-SAVING; FIRE-FIGHTING
    • A62CFIRE-FIGHTING
    • A62C31/00Delivery of fire-extinguishing material
    • A62C31/02Nozzles specially adapted for fire-extinguishing
    • A62C31/24Nozzles specially adapted for fire-extinguishing attached to ladders, poles, towers, or other structures with or without rotary heads
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05BSPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B3/00Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
    • B05B3/02Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements

Landscapes

  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Fluid-Damping Devices (AREA)
  • Power Steering Mechanism (AREA)

Abstract

A rotary actuator comprises a cylinder 12 with a cup-shaped end cap 15, and an internally splined annular piston 11 with a piston rod 16 which has helically inclined teeth 19 on its external surface. The teeth 19 are engaged by a nut 14 fixed to the cylinder, and the internal splines 23 of the piston are engaged by a splined shaft 20 which projects from one end of the cylinder and which constitutes the output shaft. The end of the piston rod 16 remote from the piston is sealed by a plug 17 replaceable by a different length plug for limiting movement and a passage 31 through the piston places the interior of the piston rod in permanently open communication with the cylinder space at the opposite side of the piston. Pressure fluid can be supplied to either side of the piston. As the piston moves axially it is constrained by the nut 14 to rotate, the rotation being transmitted to the output shaft through the splined connection. <IMAGE>

Description

SPECIFICATION Improvements relating to rotary actuators This invention relates to rotary actuators and has a particularly useful but not exclusive application in driving a remote control monitor in fire-fighting.
According to this invention there is provided a rotary actuator comprising a piston having a piston rod the external surface of which is formed with one or more helical ribs and/or grooves, a cylinder in which the piston is slidably mounted and which totally encloses the piston and piston rod, a nut fixed with respect to the cylinder and engaged with the helical rib(s) and/or groove(s) on the piston, a shaft mounted in a bearing at the end of the cylinder remote from the piston rod for rotation coaxially with the piston said shaft having one end thereof projecting from the cylinder and having its other end portion in splined engagement with the piston over the full axial extent of sliding movement of the piston, and means whereby pressure fluid can be supplied to the cylinder space at each side of the piston.
According to a preferred feature of the invention the piston rod is hollow and accommodates any portion of the shaft projecting axially beyond the splines during axial movement of the piston and the hollow interior of the piston is sealed from the cylinder space surrounding the piston rod but is in permanently open communication with the cylinder space at the side of the piston remote from the piston rod.
One embodiment of the invention will now be described with reference to the accompanying drawing which shows, in axial section, a rotary actuator according to the invention.
Referring to the drawing, the actuator is a hydraulic actuator incorporating a cylinder 10 and piston 1 The cylinder comprises a main body 1 2 having an annular first end cap 13 secured to one end thereof, and a nut 14 and a cup-shaped second annular end cap 1 5 secured to the other end. The piston has a hollow piston rod 1 6 the end of which remote from the piston is sealed by a plug 1 7 threaded into the piston rod and carrying a stop bolt 1 8. The external surface of the piston rod has a number of helical ribs 1 9 which are engaged in complementary grooves in the nut 14, so that axial movement of the piston causes the piston and piston rod to rotate.The angle of rotation can be varied either by changing the length of screw-thread form on the piston or by replacing the stop bolt 1 8 by a longer bolt. In the particular example illustrated, the length and helix angle of the helical ribs are such that the piston rotates through two complete revolutions (7200.) in moving from one end to the other of its axial travel. The piston rod 1 6 is enclosed by the cupshaped end cap 1 5.
An output shaft 20 is mounted coaxially with the piston in a bearing 22 in the end cap 13 and has one end portion projecting from the cylinder.
The other end portion of the shaft is splined along the whole of its length within the cylinder and extends along the full length of the cylinder, and is in splined engagement with a complementary formation at 23 in the piston. Thus the rotational movement of the piston 11 is transmitted to the output shaft 20. An annular rib 24 on the shaft is disposed in a recess on the inner face of the end cap 13 and a circlip 25 engaged in a groove in the recess locates the rib axially between itself and the bottom of the recess to take the small axial thrusts on the shaft resulting from friction in the splined connection and fluid pressure acting on the inner end face of the shaft.
First and second connection points 26, 27 for the supply of pressure fluid to opposite sides of the piston are respectively formed in the two end caps 13, 1 5. Connection point 26 leads through a short axial passage 28 to the cylinder space 29 at one side of the piston. Connection point 27 leads via a radial passage 29 to the interior of the cup formation, and a transfer passage 30 extends axially through the nut to the cylinder space at the other side of the piston. A passage 31 extends through the piston from cylinder space and opens to the space between the shaft and the piston rod.
It will therefore be seen that the effective areas of the two sides of the piston are the same and are substantially equal to the cross-sectional area of the bore of the main body 12 of the cylinder.
At the two limits of its movement the piston comes into abutment with the end cap 1 3 and stop bolt 18.
1. A rotary actuator comprising a piston having a piston rod the external surface of which is formed with one or more helical ribs and/or grooves, a cylinder in which the piston is slidably mounted and which totally encloses the piston and piston rod, a nut fixed with respect to the cylinder and engaged with the helical rib(s) and/or groove(s) on the piston, a shaft mounted in a bearing at the end of the cylinder remote from the piston rod for rotation coaxially with the piston said shaft having one end thereof projecting from the cylinder and having its other end portion in splined engagement with the piston over the full axial extent of sliding movement of the piston, and means whereby pressure fluid can be supplied to the cylinder space at each side of the piston.
2. A rotary actuator as claimed in claim 1, wherein the piston rod is hollow and accommodates any portion of the shaft projecting axially beyond the splines during axial movement of the piston and wherein the hollow interior of the piston is sealed from the cylinder space surrounding the piston rod but is in permanently open communication with the cylinder space at the side of the piston remote from the piston rod.
3. A rotary actuator as claimed in claim 1 or claim 2, wherein a stop bolt is mounted at the end of the piston rod remote from the piston and comes into abutment with that end of the cylinder,
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements relating to rotary actuators This invention relates to rotary actuators and has a particularly useful but not exclusive application in driving a remote control monitor in fire-fighting. According to this invention there is provided a rotary actuator comprising a piston having a piston rod the external surface of which is formed with one or more helical ribs and/or grooves, a cylinder in which the piston is slidably mounted and which totally encloses the piston and piston rod, a nut fixed with respect to the cylinder and engaged with the helical rib(s) and/or groove(s) on the piston, a shaft mounted in a bearing at the end of the cylinder remote from the piston rod for rotation coaxially with the piston said shaft having one end thereof projecting from the cylinder and having its other end portion in splined engagement with the piston over the full axial extent of sliding movement of the piston, and means whereby pressure fluid can be supplied to the cylinder space at each side of the piston. According to a preferred feature of the invention the piston rod is hollow and accommodates any portion of the shaft projecting axially beyond the splines during axial movement of the piston and the hollow interior of the piston is sealed from the cylinder space surrounding the piston rod but is in permanently open communication with the cylinder space at the side of the piston remote from the piston rod. One embodiment of the invention will now be described with reference to the accompanying drawing which shows, in axial section, a rotary actuator according to the invention. Referring to the drawing, the actuator is a hydraulic actuator incorporating a cylinder 10 and piston 1 The cylinder comprises a main body 1 2 having an annular first end cap 13 secured to one end thereof, and a nut 14 and a cup-shaped second annular end cap 1 5 secured to the other end. The piston has a hollow piston rod 1 6 the end of which remote from the piston is sealed by a plug 1 7 threaded into the piston rod and carrying a stop bolt 1 8. The external surface of the piston rod has a number of helical ribs 1 9 which are engaged in complementary grooves in the nut 14, so that axial movement of the piston causes the piston and piston rod to rotate.The angle of rotation can be varied either by changing the length of screw-thread form on the piston or by replacing the stop bolt 1 8 by a longer bolt. In the particular example illustrated, the length and helix angle of the helical ribs are such that the piston rotates through two complete revolutions (7200.) in moving from one end to the other of its axial travel. The piston rod 1 6 is enclosed by the cupshaped end cap 1 5. An output shaft 20 is mounted coaxially with the piston in a bearing 22 in the end cap 13 and has one end portion projecting from the cylinder. The other end portion of the shaft is splined along the whole of its length within the cylinder and extends along the full length of the cylinder, and is in splined engagement with a complementary formation at 23 in the piston. Thus the rotational movement of the piston 11 is transmitted to the output shaft 20. An annular rib 24 on the shaft is disposed in a recess on the inner face of the end cap 13 and a circlip 25 engaged in a groove in the recess locates the rib axially between itself and the bottom of the recess to take the small axial thrusts on the shaft resulting from friction in the splined connection and fluid pressure acting on the inner end face of the shaft. First and second connection points 26, 27 for the supply of pressure fluid to opposite sides of the piston are respectively formed in the two end caps 13, 1 5. Connection point 26 leads through a short axial passage 28 to the cylinder space 29 at one side of the piston. Connection point 27 leads via a radial passage 29 to the interior of the cup formation, and a transfer passage 30 extends axially through the nut to the cylinder space at the other side of the piston. A passage 31 extends through the piston from cylinder space and opens to the space between the shaft and the piston rod. It will therefore be seen that the effective areas of the two sides of the piston are the same and are substantially equal to the cross-sectional area of the bore of the main body 12 of the cylinder. At the two limits of its movement the piston comes into abutment with the end cap 1 3 and stop bolt 18. CLAIMS
1. A rotary actuator comprising a piston having a piston rod the external surface of which is formed with one or more helical ribs and/or grooves, a cylinder in which the piston is slidably mounted and which totally encloses the piston and piston rod, a nut fixed with respect to the cylinder and engaged with the helical rib(s) and/or groove(s) on the piston, a shaft mounted in a bearing at the end of the cylinder remote from the piston rod for rotation coaxially with the piston said shaft having one end thereof projecting from the cylinder and having its other end portion in splined engagement with the piston over the full axial extent of sliding movement of the piston, and means whereby pressure fluid can be supplied to the cylinder space at each side of the piston.
2. A rotary actuator as claimed in claim 1, wherein the piston rod is hollow and accommodates any portion of the shaft projecting axially beyond the splines during axial movement of the piston and wherein the hollow interior of the piston is sealed from the cylinder space surrounding the piston rod but is in permanently open communication with the cylinder space at the side of the piston remote from the piston rod.
3. A rotary actuator as claimed in claim 1 or claim 2, wherein a stop bolt is mounted at the end of the piston rod remote from the piston and comes into abutment with that end of the cylinder, the bolt being replaceable by a stop bolt of a different length to vary the axial position of the piston at which said abutment occurs.
4. A rotary actuator substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
GB08234988A 1981-12-23 1982-12-08 Rotary actuators Withdrawn GB2113764A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8138839 1981-12-23

Publications (1)

Publication Number Publication Date
GB2113764A true GB2113764A (en) 1983-08-10

Family

ID=10526825

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08234988A Withdrawn GB2113764A (en) 1981-12-23 1982-12-08 Rotary actuators

Country Status (4)

Country Link
DE (1) DE3246977A1 (en)
FR (1) FR2518414A1 (en)
GB (1) GB2113764A (en)
IT (1) IT1155039B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2182721A (en) * 1985-11-09 1987-05-20 Hytork Actuators Ltd Improvements in or relating to fluid-pressure-operated actuators
GB2299562A (en) * 1995-04-01 1996-10-09 Nigel Howard Mckrill Actuator for helicopter rotor blade aileron
CN109676364A (en) * 2019-03-06 2019-04-26 成都华川电装有限责任公司 Screw assembles device
CN110273938A (en) * 2018-03-16 2019-09-24 西安博贤机电设备有限公司 A kind of annular axis clutch cylinder

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3639121A1 (en) * 1986-11-15 1988-05-19 Hausherr & Soehne Rudolf Device for converting a stroke movement into a rotary movement
DE3706121A1 (en) * 1987-02-25 1988-09-08 Wolf Woco & Co Franz J Actuating drive
DE102015209725A1 (en) * 2015-05-27 2016-12-01 Nussbaum Technologies Gmbh Hydraulically operated barrier

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1229392B (en) * 1959-06-03 1966-11-24 Pleiger Maschf Paul Hydraulic swivel drive for left and right rotation with limited angle of rotation
GB1055694A (en) * 1964-06-04 1967-01-18 Inst Schiffbautechnik Wolgast Swivel device
US3977305A (en) * 1971-09-13 1976-08-31 C.O. Hansen Maskinfabrik Af 1970 A/S Operating mechanism for turning an axle end
FR2455201A1 (en) * 1979-04-27 1980-11-21 Renault Rotating hydraulic cylinder - is located between bearings and has splined piston and side connections for hydraulic fluid

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2182721A (en) * 1985-11-09 1987-05-20 Hytork Actuators Ltd Improvements in or relating to fluid-pressure-operated actuators
GB2299562A (en) * 1995-04-01 1996-10-09 Nigel Howard Mckrill Actuator for helicopter rotor blade aileron
CN110273938A (en) * 2018-03-16 2019-09-24 西安博贤机电设备有限公司 A kind of annular axis clutch cylinder
CN109676364A (en) * 2019-03-06 2019-04-26 成都华川电装有限责任公司 Screw assembles device
CN109676364B (en) * 2019-03-06 2024-04-02 成都华川电装有限责任公司 Screw assembling device

Also Published As

Publication number Publication date
DE3246977A1 (en) 1983-06-30
FR2518414A1 (en) 1983-06-24
IT8224885A0 (en) 1982-12-21
IT8224885A1 (en) 1984-06-21
IT1155039B (en) 1987-01-21

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Legal Events

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)