WO1993008415A1 - A pressure relief valve - Google Patents

A pressure relief valve Download PDF

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Publication number
WO1993008415A1
WO1993008415A1 PCT/GB1992/001825 GB9201825W WO9308415A1 WO 1993008415 A1 WO1993008415 A1 WO 1993008415A1 GB 9201825 W GB9201825 W GB 9201825W WO 9308415 A1 WO9308415 A1 WO 9308415A1
Authority
WO
WIPO (PCT)
Prior art keywords
valve
fluid flow
flow channel
fluid
valve opening
Prior art date
Application number
PCT/GB1992/001825
Other languages
French (fr)
Inventor
Jeremy George Bird
Brian David Birch
Francis Neville Corfield
Original Assignee
Dowty Aerospace Gloucester Limited
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 Dowty Aerospace Gloucester Limited filed Critical Dowty Aerospace Gloucester Limited
Priority to CA002098569A priority Critical patent/CA2098569C/en
Priority to DE69209818T priority patent/DE69209818T2/en
Priority to US08/078,254 priority patent/US5390696A/en
Priority to EP92920803A priority patent/EP0562079B1/en
Priority to JP50751193A priority patent/JP3362226B2/en
Publication of WO1993008415A1 publication Critical patent/WO1993008415A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/34—Special valve constructions; Shape or construction of throttling passages
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
    • B60G17/027—Mechanical springs regulated by fluid means
    • B60G17/0272—Mechanical springs regulated by fluid means the mechanical spring being a coil spring
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7781—With separate connected fluid reactor surface
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7837—Direct response valves [i.e., check valve type]
    • Y10T137/7847—With leak passage

Definitions

  • This invention relates to a pressure relief valve, particularly, but not exclusively, for an aircraft undercarriage damping arrangement.
  • FIG. 1 An aircraft undercarriage arrangement is shown in Figure 1 and comprises an upper leg 1 mounted at a suitable point in a wing of the aircraft, and a lower leg 2 slidably located about a lower end of the upper leg 1.
  • the lower leg 2 is connected to a wheeled bogey by a trunnion 3.
  • Upper leg 1 is hollow to define an upper cavity 4 whilst lower leg 5 defines a lower cavity 5.
  • the cavities are separated by an end wall 6 and the lower cavity filled with a damping oil and the upper cavity filled with damping oil and nitrogen gas.
  • the oil is allowed to flow through a valve 7 mounted in the end wall 6 to permit a controlled collapsing of the upper leg 1 into the lower leg 2, thereby absorbing the impact of landing.
  • valve 7 In the event of a heavy landing, it is necessary for the valve 7 to open fully to "soften” the undercarriage and avoid the impact being transmitted to passengers. In the past this has been achieved by providing a valve 7 as shown in Figure 2, with a spring-loaded orifice plate 8 which permits an initial limited flow through the orifice 9 therein, up to a predetermined pressure limit, at which the spring-loading is overcome and the plate lifts to allow an increased flow through the valve seat 8a with which the plate cooperates.
  • a problem with such existing valves is that the differential area of the orifice plate may be small at high operating pressures and the oil- flow past it when the valve is open may prevent it from being held open in a positive manner.
  • a pressure relief valve comprising a fluid flow channel through which an initial flow of fluid passes in use, and a valve opening member responsive at a predetermined fluid pressure to open the valve and allow an increased fluid flow therethrough, wherein the valve opening member is located substantially centrally in the fluid flow channel .
  • valve opening member By locating the valve opening member substantially centrally in the fluid flow channel, said member is always exposed to the fluid flow, thereby making the valve more reliable in operation.
  • the fluid flow channel is such as to reduce or eliminate any turbulent flow effects within the valve that would cause the valve opening characteristics to vary.
  • the fluid flow channel is made long enough so that its outlet is spaced away from a fluid inlet port and associated valve member controlled by the valve opening member.
  • the region around the outlet end of the fluid flow channel is screened from the fluid inlet port and associated valve member.
  • the fluid flow channel may incorporate the valve member in the form of a valve seat at its inlet end which cooperates with the valve inlet so as to take all the flow through it when the valve is closed.
  • An outer peripheral portion of the valve member may be guided within an outer housing and a screen may be provided around the outlet end of the fluid flow channel and the outer housing.
  • valve opening member is elongated in a direction substantially parallel to the axis of the fluid flow channel such that a valve opening force is exerted on it, induced by the drag of the fluid flow in the channel.
  • This is preferable since the cross-sectional area of the valve opening member may be reduced producing a less turbulent fluid flow.
  • valve opening member comprises a rod extending along the axis of the flow channel.
  • the fluid flow channel is defined by part of the valve opening member. This is preferable because the drag generated by walls defining the fluid flow channel acts to open the valve permitting a further reduction in the cross- sectional area of the central portion of the valve opening member.
  • the fluid flow channel has substantially parallel walls to produce a substantially parallel fluid flow.
  • Figure 3 shows a longitudinal section through a pressure relief valve in accordance with the invention.
  • Figure 4 shows an end view of the valve shown in Figure 3.
  • a pressure relief valve comprises a generally cylindrical body 1, closed at one end by an end wall 2 and having a radially outwardly extending mounting flange 3.
  • Bolts (not shown) pass through the flange 3 to fix the valve to an end wall 9 of an undercarriage leg which is comparable to the end wall 6 in the prior art assembly of Figure 1.
  • the other end of the body 1 is closed by an end cap 4 having a central upwards extension in which are formed four laterally opening fluid exit ports 5.
  • a fluid inlet port 6 is formed centrally in the end wall 2.
  • Pressure relief ports 7, 8 and 8a extend radially through the body 1.
  • An outer peripheral portion 10 of the end cap 4 is threaded for engagement with threads 11 on the internal surface of the body 1.
  • valve slide 13 Located within valve cavity 12 is an axially . displaceable bell-shaped, valve slide 13.
  • the valve slide 13 has axially extending peripheral lands 14 and 15 which cooperate with the ports 7 and 8, respectively.
  • the lower end wall 16 of the valve slide 13 makes contact with the end wall 2 of the body 1 under the action of an axially extending compression spring 17.
  • the spring 17 acts between an inner face of the end wall 16 and a guide washer 20 loosely located in the end cap 4.
  • a central aperture 19 is formed in the end wall 16 in alignment with, and of the same diameter as, the inlet port 6 in the body 1.
  • a limited annular sealing area 19a of the valve slide around the aperture 19 forms a seal with the end wall 2 of the body 1.
  • a cylindrical flow tube 21 is located coaxially within the valve slide 13 and is connected to it via an outer collar 22 at its lower end.
  • the upper end of the flow tube 21 projects through the aperture in the guide washer 20.
  • the inner diameter of the flow tube 21 equals that of the apertures 6 and 19 so that they form a constant cross-section flow channel.
  • Centrally located within the flow tube 21 is a pressure sensor 23 that is connected to the valve slide 13 by four radially extending arms 24 joined to an outer ring 25 which is received in a recess in the inner surface of the end wall 16 and clamped therein by the collar 22 of the flow tube which is connected by bolts (not shown) to the end wall 16 of the valve slide 13.
  • damping oil flows from the lower leg into the upper leg of an aircraft undercarriage damping arrangement via inlet port 6 and the flow tube 21 of the pressure relief valve.
  • the oil is guided laterally by means of the exit ports 5 in the end cap 4 to ensure turbulent mixing within the body of the oil.
  • the lands 14 and 15 slide back opening ports 7 and 8 and a gap opens between the valve seat 19a and the valve slide 13. Oil is then free to flow through ports 6 and 8 and on through ports 7 into the upper leg, as well as through the flow tube 21 and exit ports 5 into the upper leg. The resistance to flow experienced by the oil is thus lessened and the undercarriage enters its "softest” state. As the valve slide 13 lifts away from the end wall 2, the space between the slide 13, the flow tube 21 and the end cap 4 and washer 20 is reduced, and oil contained in this space flows outwards through the ports 8a into the upper leg.
  • end cap 4 and washer 20 together serve to screen the outlet end of the flow tube 21 from the space within the slide member 13, thereby preventing possible turbulence at the outlet end from having an adverse effect on the operating characteristics of the slide member.
  • the flow tube 21 is long enough to distance the outlet end far enough away from the slide member that such adverse turbulence effects are of no consequence, even without these components to form a screen.
  • the flow tube may be shortened. If the screen formed by the end cap 4 and washer 20 is retained, adverse turbulence effects in the valve can still be avoided.
  • the flow tube is preferably longer than its diameter and is typically longer by a factor of 2 or 3 or more.

Abstract

A pressure relief valve includes a fluid flow channel (6, 19, 21) through which an initial flow of fluid passes in use, and a valve opening member (23) responsive at a predetermined fluid pressure to open the valve (13) and allow an increased fluid flow therethrough. The valve opening member (23) is located substantially centrally in the fluid flow channel (6, 19, 21) to ensure it is always exposed to the fluid flow. Part of the flow channel (21) is formed by part of the valve (13). The valve opening member (23) and flow channel (21) are elongated and parallel. Screen means (13) on the valve screens the outlet end of the channel (21) from the fluid inlet port (6).

Description

A PRESSURE RELIEF VALVE
This invention relates to a pressure relief valve, particularly, but not exclusively, for an aircraft undercarriage damping arrangement.
An aircraft undercarriage arrangement is shown in Figure 1 and comprises an upper leg 1 mounted at a suitable point in a wing of the aircraft, and a lower leg 2 slidably located about a lower end of the upper leg 1. The lower leg 2 is connected to a wheeled bogey by a trunnion 3. Upper leg 1 is hollow to define an upper cavity 4 whilst lower leg 5 defines a lower cavity 5. The cavities are separated by an end wall 6 and the lower cavity filled with a damping oil and the upper cavity filled with damping oil and nitrogen gas. The oil is allowed to flow through a valve 7 mounted in the end wall 6 to permit a controlled collapsing of the upper leg 1 into the lower leg 2, thereby absorbing the impact of landing.
In the event of a heavy landing, it is necessary for the valve 7 to open fully to "soften" the undercarriage and avoid the impact being transmitted to passengers. In the past this has been achieved by providing a valve 7 as shown in Figure 2, with a spring-loaded orifice plate 8 which permits an initial limited flow through the orifice 9 therein, up to a predetermined pressure limit, at which the spring-loading is overcome and the plate lifts to allow an increased flow through the valve seat 8a with which the plate cooperates.
A problem with such existing valves is that the differential area of the orifice plate may be small at high operating pressures and the oil- flow past it when the valve is open may prevent it from being held open in a positive manner.
According to the invention there is provided a pressure relief valve comprising a fluid flow channel through which an initial flow of fluid passes in use, and a valve opening member responsive at a predetermined fluid pressure to open the valve and allow an increased fluid flow therethrough, wherein the valve opening member is located substantially centrally in the fluid flow channel .
By locating the valve opening member substantially centrally in the fluid flow channel, said member is always exposed to the fluid flow, thereby making the valve more reliable in operation.
Preferably, the fluid flow channel is such as to reduce or eliminate any turbulent flow effects within the valve that would cause the valve opening characteristics to vary. In particular, the fluid flow channel is made long enough so that its outlet is spaced away from a fluid inlet port and associated valve member controlled by the valve opening member. Preferably, the region around the outlet end of the fluid flow channel is screened from the fluid inlet port and associated valve member. For example, the fluid flow channel may incorporate the valve member in the form of a valve seat at its inlet end which cooperates with the valve inlet so as to take all the flow through it when the valve is closed. An outer peripheral portion of the valve member may be guided within an outer housing and a screen may be provided around the outlet end of the fluid flow channel and the outer housing.
Preferably, the valve opening member is elongated in a direction substantially parallel to the axis of the fluid flow channel such that a valve opening force is exerted on it, induced by the drag of the fluid flow in the channel. This is preferable since the cross-sectional area of the valve opening member may be reduced producing a less turbulent fluid flow.
Conveniently, the valve opening member comprises a rod extending along the axis of the flow channel.
Preferably, the fluid flow channel is defined by part of the valve opening member. This is preferable because the drag generated by walls defining the fluid flow channel acts to open the valve permitting a further reduction in the cross- sectional area of the central portion of the valve opening member.
Advantageously, the fluid flow channel has substantially parallel walls to produce a substantially parallel fluid flow.
By producing a parallel fluid flow, turbulence is avoided which might produce a closing force on the valve acting in the opposite direction to the general fluid flow direction.
A specific embodiment of the invention will now be described, by way of example only, with reference to the drawings in which:
Figure 3 shows a longitudinal section through a pressure relief valve in accordance with the invention; and
Figure 4 shows an end view of the valve shown in Figure 3.
With reference to Figures 3 and 4, a pressure relief valve comprises a generally cylindrical body 1, closed at one end by an end wall 2 and having a radially outwardly extending mounting flange 3. Bolts (not shown) pass through the flange 3 to fix the valve to an end wall 9 of an undercarriage leg which is comparable to the end wall 6 in the prior art assembly of Figure 1. The other end of the body 1 is closed by an end cap 4 having a central upwards extension in which are formed four laterally opening fluid exit ports 5. A fluid inlet port 6 is formed centrally in the end wall 2. Pressure relief ports 7, 8 and 8a extend radially through the body 1.
An outer peripheral portion 10 of the end cap 4 is threaded for engagement with threads 11 on the internal surface of the body 1.
Located within valve cavity 12 is an axially . displaceable bell-shaped, valve slide 13. The valve slide 13 has axially extending peripheral lands 14 and 15 which cooperate with the ports 7 and 8, respectively. The lower end wall 16 of the valve slide 13 makes contact with the end wall 2 of the body 1 under the action of an axially extending compression spring 17. The spring 17 acts between an inner face of the end wall 16 and a guide washer 20 loosely located in the end cap 4. A central aperture 19 is formed in the end wall 16 in alignment with, and of the same diameter as, the inlet port 6 in the body 1. A limited annular sealing area 19a of the valve slide around the aperture 19 forms a seal with the end wall 2 of the body 1.
A cylindrical flow tube 21 is located coaxially within the valve slide 13 and is connected to it via an outer collar 22 at its lower end. The upper end of the flow tube 21 projects through the aperture in the guide washer 20. The inner diameter of the flow tube 21 equals that of the apertures 6 and 19 so that they form a constant cross-section flow channel. Centrally located within the flow tube 21 is a pressure sensor 23 that is connected to the valve slide 13 by four radially extending arms 24 joined to an outer ring 25 which is received in a recess in the inner surface of the end wall 16 and clamped therein by the collar 22 of the flow tube which is connected by bolts (not shown) to the end wall 16 of the valve slide 13. During normal landing conditions, damping oil flows from the lower leg into the upper leg of an aircraft undercarriage damping arrangement via inlet port 6 and the flow tube 21 of the pressure relief valve. The oil is guided laterally by means of the exit ports 5 in the end cap 4 to ensure turbulent mixing within the body of the oil.
In the event of a heavy landing, the fluid flow will increase. A pressure is then exerted on an end face 26 of the pressure sensor 23 and the arms 24, which together with the drag generated by the axially extending surfaces of the pressure sensor 23 and flow tube 21, opens the valve by forcing the valve slide 13 upwards against the spring 17.
The lands 14 and 15 slide back opening ports 7 and 8 and a gap opens between the valve seat 19a and the valve slide 13. Oil is then free to flow through ports 6 and 8 and on through ports 7 into the upper leg, as well as through the flow tube 21 and exit ports 5 into the upper leg. The resistance to flow experienced by the oil is thus lessened and the undercarriage enters its "softest" state. As the valve slide 13 lifts away from the end wall 2, the space between the slide 13, the flow tube 21 and the end cap 4 and washer 20 is reduced, and oil contained in this space flows outwards through the ports 8a into the upper leg.
As the landing impact is absorbed the flow rate and pressure within the damping arrangement reduces, and the valve slide 13 seats on the valve seat 19a again under the action of spring 17.
It will be appreciated that the end cap 4 and washer 20 together serve to screen the outlet end of the flow tube 21 from the space within the slide member 13, thereby preventing possible turbulence at the outlet end from having an adverse effect on the operating characteristics of the slide member. However, it may be in some applications that the flow tube 21 is long enough to distance the outlet end far enough away from the slide member that such adverse turbulence effects are of no consequence, even without these components to form a screen.
In an alternative embodiment, the flow tube may be shortened. If the screen formed by the end cap 4 and washer 20 is retained, adverse turbulence effects in the valve can still be avoided. However, the flow tube is preferably longer than its diameter and is typically longer by a factor of 2 or 3 or more.

Claims

1. A pressure relief valve comprising a fluid flow channel through which an initial flow of fluid passes in use, and a valve opening member responsive at a predetermined fluid pressure to open the valve and allow an increased fluid flow therethrough, characterised in that the valve opening member (23) is located substantially centrally in the fluid flow channel (6, 19, 21).
2. A valve as claimed in claim 1 wherein the fluid flow channel (6, 19, 21) has its outlet spaced away from a fluid inlet port (6) and associated valve member (16) controlled by the valve opening member (23).
3. A valve as claimed in claim 1 or claim 2 wherein screen means (13) is included to screen a region around the outlet end of the fluid flow channel (6, 19, 21) from a fluid inlet port (6) and associated valve member (16).
4. A valve as claimed in claim 3 in which the screen means (13) is part of the valve member ( 16 )
5. A valve as claimed in claim 2 in which the valve member (16) is centred on the fluid flow channel (6, 19, 21) and has an outer annular land
(14) which cooperates with a port (7) in an outer annular housing (1) so as to open said port (7) when the valve member (16) is operated to allow said increased fluid flow.
6. A valve as claimed in claim 5 in which the valve member (16) has a second outer annular land
(15) which cooperates with a second port (8) in the outer annular housing (1) so as to open said port (8) when the valve member (16) is operated to allow additional fluid flow into the housing which exits through said port (7) .
7. A valve as claimed in claim 5 or 6 in which the valve member (16) includes screen means (13) to screen a region around the outlet end of the fluid flow channel (6, 19, 21) from the fluid inlet port (6) .
8. A valve as claimed in any preceding claim wherein the valve opening member (23) is elongated in a direction substantially parallel to the axis of the fluid flow channel (6, 19, 21) such that a valve opening force is exerted on it, induced by the drag of the fluid flow in the channel.
9. A valve as claimed in claim 8 wherein the valve opening member (23) comprises a rod extending along the axis of the flow channel (6, 19, 21).
10. A valve as claimed in any preceding claim wherein the fluid flow channel (6, 19, 21) is defined by part of the valve opening member (23).
11. A valve as claimed in any preceding claim wherein the fluid flow channel (6, 19, 21) has substantially parallel walls to produce a substantially parallel fluid flow.
12. An aircraft undercarriage damping system incorporating a pressure relief valve as claimed in any one of the preceding claims.
PCT/GB1992/001825 1991-10-17 1992-10-07 A pressure relief valve WO1993008415A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA002098569A CA2098569C (en) 1991-10-17 1992-10-07 Pressure relief valve
DE69209818T DE69209818T2 (en) 1991-10-17 1992-10-07 PRESSURE VALVE
US08/078,254 US5390696A (en) 1991-10-17 1992-10-07 Pressure relief valve
EP92920803A EP0562079B1 (en) 1991-10-17 1992-10-07 A pressure relief valve
JP50751193A JP3362226B2 (en) 1991-10-17 1992-10-07 Pressure relief valve

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9122070.7 1991-10-17
GB9122070A GB2260595B (en) 1991-10-17 1991-10-17 A pressure relief valve

Publications (1)

Publication Number Publication Date
WO1993008415A1 true WO1993008415A1 (en) 1993-04-29

Family

ID=10703101

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/001825 WO1993008415A1 (en) 1991-10-17 1992-10-07 A pressure relief valve

Country Status (8)

Country Link
US (1) US5390696A (en)
EP (1) EP0562079B1 (en)
JP (1) JP3362226B2 (en)
CA (1) CA2098569C (en)
DE (1) DE69209818T2 (en)
ES (1) ES2088595T3 (en)
GB (1) GB2260595B (en)
WO (1) WO1993008415A1 (en)

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US6554857B1 (en) 1999-07-20 2003-04-29 Medtronic, Inc Transmural concentric multilayer ingrowth matrix within well-defined porosity
US6354092B1 (en) 2000-08-21 2002-03-12 York International Corporation Method and valve for arresting liquid at intake of refrigeration compressor
US7097120B2 (en) 2001-11-29 2006-08-29 Watershield Llc Hose nozzle apparatus and method
US7258285B1 (en) * 2005-01-14 2007-08-21 Elkhart Brass Manufacturing Company, Inc. Adjustable smooth bore nozzle
US9919171B2 (en) 2007-07-12 2018-03-20 Watershield Llc Fluid control device and method for projecting a fluid
US9004376B2 (en) 2007-07-12 2015-04-14 Watershield Llc Fluid control device and method for projecting a fluid
EP2242544A2 (en) 2007-12-12 2010-10-27 Elkhart Brass Manufacturing Company, Inc. Smooth bore nozzle with adjustable bore
DE102008002467A1 (en) * 2008-06-17 2009-12-24 Robert Bosch Gmbh Dosing system for a liquid medium, in particular urea-water solution
FI125547B (en) 2014-02-19 2015-11-30 Heikki Antero Pohjola Method and apparatus for maintaining the system fluid flow pressure at a predetermined, almost constant level

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Publication number Priority date Publication date Assignee Title
FR1018903A (en) * 1950-04-15 1953-01-14 Coordination Ind & Commerciale Improvements to damper valves
FR79539E (en) * 1960-06-09 1962-12-14 Hydraulic shock absorber for buffers of railway vehicles
DE1268990B (en) * 1957-07-12 1968-05-22 Boge Gmbh Pistons for double-acting hydraulic vibration dampers, especially for motor vehicles
AT365990B (en) * 1977-05-02 1982-02-25 Granig Hubert Dkfm SHOCK ABSORBING, TELESCOPICALLY SLIDING, HYDRAULIC PISTON-CYLINDER UNIT
US4823922A (en) * 1987-07-02 1989-04-25 Maremont Corporation Heavy duty vehicular shock absorber
DE8906232U1 (en) * 1989-05-19 1989-07-20 Iir Innovations- Und Investitionsgesellschaft Mbh, 2370 Rendsburg, De

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DE3302784A1 (en) * 1983-01-28 1984-08-02 Arthur Pfeiffer Vakuumtechnik Wetzlar Gmbh, 6334 Asslar OVERFLOW VALVE WITH DIFFERENTIAL PRESSURE CONTROL

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1018903A (en) * 1950-04-15 1953-01-14 Coordination Ind & Commerciale Improvements to damper valves
DE1268990B (en) * 1957-07-12 1968-05-22 Boge Gmbh Pistons for double-acting hydraulic vibration dampers, especially for motor vehicles
FR79539E (en) * 1960-06-09 1962-12-14 Hydraulic shock absorber for buffers of railway vehicles
AT365990B (en) * 1977-05-02 1982-02-25 Granig Hubert Dkfm SHOCK ABSORBING, TELESCOPICALLY SLIDING, HYDRAULIC PISTON-CYLINDER UNIT
US4823922A (en) * 1987-07-02 1989-04-25 Maremont Corporation Heavy duty vehicular shock absorber
DE8906232U1 (en) * 1989-05-19 1989-07-20 Iir Innovations- Und Investitionsgesellschaft Mbh, 2370 Rendsburg, De

Also Published As

Publication number Publication date
GB9122070D0 (en) 1991-11-27
JP3362226B2 (en) 2003-01-07
JPH06505549A (en) 1994-06-23
GB2260595A (en) 1993-04-21
GB2260595B (en) 1995-05-31
EP0562079A1 (en) 1993-09-29
US5390696A (en) 1995-02-21
DE69209818D1 (en) 1996-05-15
CA2098569A1 (en) 1993-04-18
EP0562079B1 (en) 1996-04-10
ES2088595T3 (en) 1996-08-16
DE69209818T2 (en) 1996-09-05
CA2098569C (en) 2003-12-09

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