EP0172708A2 - Support télescopique - Google Patents

Support télescopique Download PDF

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Publication number
EP0172708A2
EP0172708A2 EP85305635A EP85305635A EP0172708A2 EP 0172708 A2 EP0172708 A2 EP 0172708A2 EP 85305635 A EP85305635 A EP 85305635A EP 85305635 A EP85305635 A EP 85305635A EP 0172708 A2 EP0172708 A2 EP 0172708A2
Authority
EP
European Patent Office
Prior art keywords
piston
cylinder
strut
actuating rod
rod
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Withdrawn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
EP85305635A
Other languages
German (de)
English (en)
Other versions
EP0172708A3 (fr
Inventor
Michael Downie
John Colston Patrick
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.)
Delvedell Ltd
Original Assignee
Delvedell 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 Delvedell Ltd filed Critical Delvedell Ltd
Publication of EP0172708A2 publication Critical patent/EP0172708A2/fr
Publication of EP0172708A3 publication Critical patent/EP0172708A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47C—CHAIRS; SOFAS; BEDS
    • A47C3/00—Chairs characterised by structural features; Chairs or stools with rotatable or vertically-adjustable seats
    • A47C3/20—Chairs or stools with vertically-adjustable seats
    • A47C3/30—Chairs or stools with vertically-adjustable seats with vertically-acting fluid cylinder

Definitions

  • This invention relates to telescopic struts.
  • struts are often filled with a compressible fluid, generally a gas, but they may also be filled with a non-compressible fluid such as oil.
  • a telescopic strut lockable in stepless increments of extension, comprises an outer cylinder separated into first and second chambers by a piston, having an inner cylinder passing through the piston to connect the first and second chambers when a valve associated with the inner cylinder is open.
  • Fluid seals are provided between the piston and the inner walls of the outer cylinder and between the piston and the outer walls of the inner cylinder.
  • the inner cylinder preferably runs substantially the length of the outer cylinder and is connected to the outer cylinder at a point at or adjacent the end of the outer cylinder remote from the end of the outer cylinder through which a piston rod attached to the said piston passes.
  • the connection of the inner cylinder to the outer cylinder is therefore preferably at a point outside the normal range of movements of the piston within the outer cylinder.
  • valve arrangement through which passage of fluid between the inner and outer cylinders occurs is preferably located at or adjacent to the point at which the inner cylinder is connected to the outer cylinder, again at a point outside the normal range of movement of the piston within the outer cylinder as the mechanism by which the valve may be opened and closed may be in accordance with known arrangements.
  • the valve and inner cylinder are constructed as a unit.
  • the valve/inner cylinder unit comprises a tube extending through a sealing arrangement in the end of the outer cylinder, sealed at its outer end.
  • the arrangement is such that pressure on the outer end of the valve/cylinder arrangement causes an otherwise obstructed passage to the interior of the inner cylinder to come into communication with the interior of the outer cylinder and thereby allow fluid to pass between the two.
  • the inner cylinder can be considered to be an extension of the valve body.
  • a flange formed on the cylinder by welding or for example by crimping of the cylinder surface is provided to limit movement of the inner cylinder in relation to the outer cylinder and the seals therebetween.
  • a telescopic strut comprising a sealed cylinder containing a fluid, a piston fitted in the cylinder and sealed to the cylinder wall, a hollow piston rod extending from one side of the piston and having a closed end which extends out of one end of the cylinder, a hollow actuating rod extending axially of the strut through the piston to communicate with the hollow piston rod and extending at its closed end through the other end of the cylinder, and valve means operable by axial displacement of the actuating rod to open and close fluid communication from one side of the piston to the other.
  • the valve means is preferably provided by sealing the outermost end of the actuating rod, providing an aperture through the wall of the hollow piston - rod on said one side of the piston, there being an annular fluid passage between the outer diameter of the actuating rod and the inner diameter of the piston rod, providing an aperture through the wall of the actuating rod and arranging the actuating rod so that the aperture through its wall is normally blocked off, but can be displaced axially to allow the interior of the actuating rod to communicate, through the aperture, with the fluid space in the cylinder on the other side of the piston.
  • the aperture through the wall of the actuating rod is preferably blocked off by a plug fitted at one end of the cylinder into which the aperture enters when the actuating rod is not axially displaced.
  • the plug may include a pair of '0' rings which will seal around the actuating rod on either side of the aperture therein, thereby forming a spool valve.
  • the portion of the actuating rod containing the aperture may be necked, so that the edges of the aperture do not move against the 'O' ring seals which might reduce the life of these seals. ;
  • the cylinder is preferably sealed, at the end from which the piston rod extends, by a lubricated or self lubricating seal.
  • the invention provides a telescopic strut comprising a sealed cylinder containing a fluid, a piston fitted in the cylinder and sealed to the cylinder wall, a hollow piston rod extending from one side of the piston and out of one end of the cylinder, a hollow actuating rod extending axially in the cylinder on the other side of the piston with one end of the actuating rod extending out of the other end of the cylinder and the other end of the actuating rod extending through the piston and inside the piston rod, and valve means operable by axial displacement of the actuating rod to open and close fluid communication from one side of the piston to the other.
  • the fluid is preferably compressible and is preferably a gas.
  • valve means may be provided as set forth above and can be produced very simply.
  • the strut is preferably used with the piston rod projecting downwards from the cylinder, and the exposed end of the actuating rod at the top of the strut.
  • the seal which closes the bottom end of the cylinder may include two back-to-back seals to prevent fluid leaving the cylinder and also to prevent any possibility of any foreign matter entering the cylinder under extreme conditions of use.
  • a telescopic strut comprising a sealed cylinder with two pistons in the cylinder, a first of the pistons separating a first space containing a non-compressible fluid from a second space containing a compressible fluid with the second piston being located in the first space, a piston rod connected to the second piston and an actuating rod extending axially of the strut and through the second piston, and valve means operable by an axial displacement of the actuating rod to open and close fluid communication from one side of the second piston to the other.
  • a non-compressible fluid occupying the major part of the internal volume of the cylinder, means that the strut, when locked, is relatively rigid. In contrast, when gas or another compressible fluid is used, the strut will have a certain amount of "give" when locked.
  • the valve means may be constructed in a similar manner to that set forth above.
  • the first piston preferably is freely movable in the cylinder, in response to the pressures of the fluids on either side, but may be limited by a stop fixed in the cylinder in the non-compressible fluid space. Additionally, it may be advantageous to provide a second stop on the other side of the first piston.
  • the first piston can be on the piston rod side of the second piston.
  • the strut shown in Figure 1 has a cylinder 10 containing a piston 12.
  • the piston 12 is sealed against the cylinder walls by an '0' ring 14.
  • the two ends of the cylinder 10 are closed by plugs 16 and 18.
  • a hollow piston rod 20 extends from the piston 12 and out of the right-hand end (as shown in Figure 1) of the cylinder.
  • the end of the piston rod 20 is closed by a plug 22.
  • An aperture 24 in the wall of the piston rod 20 allows communication between the interior of the cylinder to the right of the piston 12 and the interior of the piston rod.
  • the strut shown contains gas under pressure.
  • a small quantity of lubricant is introduced into the cylinder 10 on assembly.
  • An actuating rod 26 is also hollow and is closed at its outer end by a plug 28.
  • the actuating rod extends through the piston 12 where it is sealed by means of an '0' ring 30 and into the interior of the piston rod 20.
  • the actuating rod is provided with a radial enlargement 32 which limits its movement out of the cylinder, and has an aperture 34 through the wall of the rod.
  • the actuator rod 26 is pressed axially into the cylinder.
  • the aperture 34 will communicate with the interior of the cylinder on the left-hand side of the piston 12, and gas can then flow from one side of the piston to the other. If there is a load on the piston rod 20 at the time, the piston 12 will move to the left and gas from the left-hand side of the piston will flow through the aperture 34, along the hollow wall of the rod 26, into the hollow interior of the rod 20, out through the aperture 24 and into the cylinder 10 on the right-hand side of the piston 12.
  • Figure 2 shows the same components as Figure 1, but in Figure 2 the end of the cylinder 10 is tapered so that the strut can be used in applications where a standard sized, tapered end is required to mate with standard end fittings.
  • Figure 7 shows an alternative assembly where the end of the cylinder 10 is tapered.
  • the plugs 16 and 36 and the O-rings 38 and 40 are fitted at the end of the parallel-sided part of the cylinder and therefore do not have to conform to the tapered walls of the cylinder.
  • actuating member it is necessary for an actuating member to be exposed at the end of the cylinder 10.
  • either the actuating rod 26 can be extended through the tapered end of the cylinder or, as shown, a slidable plug 39 with a boss 41 can be used to transmit an actuation pressure to the actuating rod.
  • Figure 3 shows the actuating rod 26 on its own. It will be seen that the rod is upset to provide the abutment 32 which limits outward movement of the rod relative to the cylinder 10.
  • Figure 4 shows a modification where the part of the rod 26 containing the aperture 34 is reduced in diameter. This is done to prevent the edges of the aperture 34 from contact with the '0' rings 38 and 40. Because the aperture must move past at least the '0' ring 38 on its actuation, it is important that the '0' ring should not wear against the edges of the aperture and the modification shown in Figure 4 will prevent undue wear taking place.
  • Figure 5 shows a strut for use with a non-compressible medium inside the cylinder. Oil is an example of such a medium. In certain applications, it may be advantageous to use a non-compressible medium since this will make the strut more rigid when locked. However, as the strut extends or retracts, the trapped volume within the cylinder 10, actuating rod 26 and piston rod 20 will vary. A non-compressible fluid cannot cope with this variation in volume, so it is necessary to provide a facility whereby compensation is provided for such changes in the working cylinder volume.
  • an auxiliary piston 50 is provided in the cylinder.
  • This auxiliary piston is free to move in the cylinder and separates an oil-filled space 58 on its left-hand side from an air-filled space 54 on its right-hand side. The piston will be moved as a result of the prevailing pressures on either side.
  • An internal '0' ring 52 serves to seal the piston on the piston rod 20.
  • An external '0' ring 56 seals the piston 50 against the cylinder walls.
  • the piston 12 moves along the cylinder in the same manner as described for previous embodiments, and oil transfers from one side of the piston 60 to the other side 58.
  • the piston moves to the right, there is a small increase in the internal volume of the combined oil spaces 58 and 60, and this increase is taken up by expansion of the air in the space 54 and consequent movement of the auxiliary piston 50 to the left.
  • the piston 12 moves in the other direction, there is an opposite effect.
  • Figure 6 shows one type of lubricated seal which can be used adjacent the end plug 18 which bounds an air-filled space.
  • the seal is held in place by an annular rib 62 formed out of the cylinder wall.
  • a disc 64 holds an O-ring 66 in an annular cavity in a metal support 68.
  • At the other end of the support 68 is a rubber sealing ring which prevents oil contained in a space 69 from leaking out.
  • the oil lubricates the O-ring 66, and it is this 0- ring which acts as the seal to maintain the air space 54 airtight.
  • Figure 7 shows an alternative seal 67, which has a number of annular ribs in contact with the rod 20. If necessary, the grooves between the ribs may be filled with grease. Additionally or alternatively, a bush 65 of nylon, ptfe or acetal may be included to reduce the friction on the piston rod. Possibly the seal 67 itself could be of a low friction material.
  • FIG 8 shows a telescopic strut 10 according to the invention used in an office chair.
  • the strut 10 is located by a guide bush 84 secured in an outer support tube 82 supported in a chair base 78.
  • the base 78 has castors 80 and the lower end of the tube 82 is supported by a thrust swivel bearing generally indicated at 76.
  • the upper end of the strut 10 is attached to the seat framework 72 which carries a seat cushion 70.
  • An operating knob 74 is movable to operate the button 26 of the telescopic strut. Hence, movement of the knob 74 opens the valve means of the strut 10 and thereby enables the effective length of the strut to be varied, in stepless increments, to adjust the height of the seat.
  • the rod 26 is axially movable in the outer cylinder and forms an actuating rod.
  • This is preferred but not essential.
  • the embodiment of Figure 9 shows an inner transfer tube 86 which is axially fixed in the outer cylinder 88. One end of the tube 86 is attached to or integral with an end plug 90 having an annular recess 92 communicating with an axial passage 94 extending through the plug 90.
  • a valve body 95 and an adjacent outer end plug 96 accommodate a slidably operating rod or button 98 of the valve means.
  • the body 95 has a passage 102 which communicates with the annular recess 92 and the passage 94.
  • a chamber 104 at one end of the interior of the inner transfer tube 86 is sealed from the passage 102 by an O-ring seal 108.

Landscapes

  • Fluid-Damping Devices (AREA)
  • Rod-Shaped Construction Members (AREA)
  • Chairs Characterized By Structure (AREA)
EP85305635A 1984-08-14 1985-08-08 Support télescopique Withdrawn EP0172708A3 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8420623 1984-08-14
GB848420623A GB8420623D0 (en) 1984-08-14 1984-08-14 Adjustable supporting column
GB848420866A GB8420866D0 (en) 1984-08-14 1984-08-16 Telescopic strut
GB8420866 1984-08-16

Publications (2)

Publication Number Publication Date
EP0172708A2 true EP0172708A2 (fr) 1986-02-26
EP0172708A3 EP0172708A3 (fr) 1986-12-17

Family

ID=26288119

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85305635A Withdrawn EP0172708A3 (fr) 1984-08-14 1985-08-08 Support télescopique

Country Status (5)

Country Link
EP (1) EP0172708A3 (fr)
JP (1) JPS6170238A (fr)
ES (1) ES8801415A1 (fr)
GB (2) GB8420623D0 (fr)
PT (1) PT80943A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2338535A (en) * 1998-05-18 1999-12-22 Answer Products Inc Damping apparatus for bicycle forks
US6360858B2 (en) 1996-10-03 2002-03-26 Answer Products, Inc. Damping apparatus for bicycle forks
CN113061959A (zh) * 2021-03-12 2021-07-02 机械工业第九设计研究院有限公司 一种两点固定的汽车后盖电泳接漆辅具

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0516416Y2 (fr) * 1988-04-20 1993-04-30
JP6088388B2 (ja) * 2013-08-30 2017-03-01 株式会社ショーワ 懸架装置
WO2015060233A1 (fr) * 2013-10-24 2015-04-30 ピー・エス・シー株式会社 Dispositif amortisseur
CN111904599A (zh) * 2020-09-18 2020-11-10 象山县第一人民医院医疗健康集团 一种胸腔镜用机械手臂

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1062120B (de) * 1957-04-30 1959-07-23 Ewald Wiemann Maschf Doppelseitig beaufschlagbarer, druckmittelbetriebener Rueckzylinder
FR1495196A (fr) * 1965-09-22 1967-09-15 Stabilus Ind Handels Gmbh élément de réglage à longueur variable
GB1139561A (en) * 1965-02-25 1969-01-08 Fichtel & Sachs Ag Improvements in or relating to adjustable hydropneumatic support devices
DE2408052A1 (de) * 1974-02-20 1975-08-28 Suspa Federungstech Laengenverstellbare gasfeder
DE2415769A1 (de) * 1974-04-01 1975-10-16 Volkswagenwerk Ag Stufenlose, hydraulisch arbeitende verstellvorrichtung fuer einen fahrzeugsitz
FR2295340A1 (fr) * 1974-12-16 1976-07-16 Stabilus Gmbh Colonne support telescopique a reglage continu en hauteur
EP0169418A2 (fr) * 1984-07-23 1986-01-29 SOL. ID S.r.l. Mécanisme pour régler la position verticale d'éléments porteur de mobilier

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1062120B (de) * 1957-04-30 1959-07-23 Ewald Wiemann Maschf Doppelseitig beaufschlagbarer, druckmittelbetriebener Rueckzylinder
GB1139561A (en) * 1965-02-25 1969-01-08 Fichtel & Sachs Ag Improvements in or relating to adjustable hydropneumatic support devices
FR1495196A (fr) * 1965-09-22 1967-09-15 Stabilus Ind Handels Gmbh élément de réglage à longueur variable
DE2408052A1 (de) * 1974-02-20 1975-08-28 Suspa Federungstech Laengenverstellbare gasfeder
DE2415769A1 (de) * 1974-04-01 1975-10-16 Volkswagenwerk Ag Stufenlose, hydraulisch arbeitende verstellvorrichtung fuer einen fahrzeugsitz
FR2295340A1 (fr) * 1974-12-16 1976-07-16 Stabilus Gmbh Colonne support telescopique a reglage continu en hauteur
EP0169418A2 (fr) * 1984-07-23 1986-01-29 SOL. ID S.r.l. Mécanisme pour régler la position verticale d'éléments porteur de mobilier

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6360858B2 (en) 1996-10-03 2002-03-26 Answer Products, Inc. Damping apparatus for bicycle forks
GB2338535A (en) * 1998-05-18 1999-12-22 Answer Products Inc Damping apparatus for bicycle forks
GB2338535B (en) * 1998-05-18 2002-07-31 Answer Products Inc Damping apparatus for bicycle forks
US6505719B2 (en) 1998-05-18 2003-01-14 Answer Products, Inc. Damping apparatus for bicycle forks
CN113061959A (zh) * 2021-03-12 2021-07-02 机械工业第九设计研究院有限公司 一种两点固定的汽车后盖电泳接漆辅具

Also Published As

Publication number Publication date
JPS6170238A (ja) 1986-04-11
ES546122A0 (es) 1986-10-16
GB8420866D0 (en) 1984-09-19
EP0172708A3 (fr) 1986-12-17
GB8420623D0 (en) 1984-09-19
PT80943A (pt) 1986-02-10
ES8801415A1 (es) 1986-10-16

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Inventor name: DOWNIE, MICHAEL

Inventor name: PATRICK, JOHN COLSTON