CN109812163B

CN109812163B - Damping mechanism for a hinge or door closer

Info

Publication number: CN109812163B
Application number: CN201811382931.7A
Authority: CN
Inventors: 游大智; 邹忠
Original assignee: Individual
Current assignee: Ruigao Precision Hardware Technology Huizhou Co ltd
Priority date: 2017-11-20
Filing date: 2018-11-20
Publication date: 2021-04-27
Anticipated expiration: 2038-11-20
Also published as: GB201719218D0; CN109812163A; CN210530582U; GB2568530A

Abstract

The present invention relates to a damping mechanism for a hinge or door closer for controlling a rotational movement of the hinge or door closer from an open position to a closed position, the damping mechanism comprising: a housing; hinging a shaft; a damping piston moving about an axis perpendicular to the hinge shaft axis; a flapper extending across the bore in the housing behind the piston and distal to the hinge shaft axis, the flapper having an orifice; the bore, the piston, and the first side of the baffle form a first space of liquid, the volume of the first space increasing and decreasing as the piston moves; a second interval including: a variable volume reservoir in communication with the orifice on the baffle; and means for pressurizing the liquid in the variable volume reservoir; a valve mechanism for controlling the flow of liquid through the orifice of the flapper, the valve mechanism causing the flow of liquid from the first compartment through the orifice to the second compartment to be controllably restricted.

Description

Damping mechanism for a hinge or door closer

Technical Field

The present invention relates to a damping mechanism for a hinge of a door, door closer or other closure. The invention relates particularly, but not exclusively, to a damped hinge or closure for framed or frameless glass, wooden or other doors. The hinge may be a damped self closing hinge. Alternatively, the hinge may be used to provide a damping action in combination with a separate self-closing mechanism. Furthermore, as yet another alternative, the hinge or door closer may be used to dampen the motion of a manually closeable door. In this specification, the hinge and the door closer are collectively referred to as a hinge for the sake of brevity.

Background

Known hinges, for example as disclosed in GB 2472883 or GB 2484527, comprise a passage forming a loop containing oil or other hydraulic fluid, the loop being arranged such that movement of the damping piston from the closed position to the open position causes the fluid to flow freely in the loop, and the loop being further arranged such that movement of the damping piston from the open position to the closed position causes the fluid to flow restrictedly, thereby damping the closing movement.

The restriction of the flow of liquid may be achieved by a screw valve that is adjustable to control the cross-section of the oil passage to restrict the oil flow when the hinge is moved in the closing direction. A one-way valve may be provided to bypass the screw valve, allowing oil to flow relatively freely when the hinge is moved in the opening direction. As the hinge completes the opening and closing cycle, the oil moves around a loop within the hinge housing.

Disclosure of Invention

According to the present invention, a damping mechanism for a hinge or door closer for controlling rotational movement of the hinge or door closer from an open position to a closed position, the damping mechanism comprising:

a housing;

a hinge shaft mounted for rotation about an axis relative to the housing;

a damping piston directly or indirectly engaging the cam surface of the hinge shaft;

the damping piston is installed in a hole in the housing to move about an axis perpendicular to the axis of the hinge shaft;

the damping piston includes a piston head and a piston body extending rearwardly from the head, the piston head extending from a bore;

the piston head is pushed forward into engagement with the cam surface;

the cam surface is configured to move the damping piston rearwardly away from the hinge axis as the hinge moves to the closed position;

a flapper extending across the bore behind the piston and distal to the hinge axis, the flapper having two sides and an orifice communicating the two sides;

the bore, the piston and the first side of the baffle form a first space of liquid, the volume of which increases as the piston moves toward the axis of the hinge shaft and decreases as the piston moves away from the axis of the hinge shaft;

a second interval including: a variable volume reservoir in communication with the orifice on the second side of the baffle; and means for pressurizing the liquid in the variable volume reservoir;

a valve mechanism for controlling the flow of liquid through the orifice of the baffle, the valve mechanism allowing liquid to flow from the second interval through the orifice to the first interval; the valve mechanism allows a controllable restriction of the liquid flow from the first interval through the orifice to the second interval.

The first or second liquid compartment may form a sealed unit together with any interconnecting passage. In use, the liquid may be reciprocated between a first interval and a second interval. During the opening and closing movement of the hinge, the liquid flows between the spaces through the orifices in alternating directions, usually in a forward or backward direction with respect to the axis of the hinge shaft. This arrangement differs from the prior art hinges in that in use the liquid flows in one direction around the damping loop.

The provision of the sealing unit allows the liquid containing parts of the damping mechanism to be provided as separate components, thereby facilitating manufacture and maintenance of the hinge. The liquid may flow along the piston axis.

The hinge according to the invention allows to overcome the drawbacks observed with previous hinges. Manufacturing a hinge with the previously disclosed oil circuit involves drilling a channel in the housing to form the oil circuit. Machining the oil passages requires precision tooling and increases manufacturing costs. Closing the outwardly open hole with a screw or other threaded member also increases costs and may leak over long periods of use. The outwardly open aperture detracts from the appearance and makes it necessary to provide a decorative shell covering the outer shell.

Frequent use of the hinge and/or extreme ambient temperatures can lead to the accumulation of metal deposits in the internal cavity of the hinge. By forcing the oil through a restricted orifice, such as a screw valve, a higher hydraulic pressure is created. Such high pressure differentials can drive deposits, causing damage to the interface and moving parts, particularly over extended periods of use. High hydraulic pressures can be avoided or reduced in the hinge of the present invention, solving these problems.

The variable volume reservoir may comprise an aperture in the housing or a removable housing in the aperture, the aperture communicating with the second side of the baffle, the region of the aperture remote from the baffle being closed by a pressure-reducing piston, the pressure-reducing piston being movable within the aperture when the pressure-reducing piston is urged towards the baffle by resilient means to vary the volume of the reservoir.

The resilient means may comprise a spring, for example a compression spring. The resilient means may be arranged, in use, to apply pressure to the liquid in the reservoir as the volume of the first compartment increases, when the hinge is rotated, to urge the liquid into the first compartment. As the volume of the second compartment decreases from a maximum value to a minimum value, the force exerted by the resilient means does not exceed a selected maximum value for fluid flow into the reservoir.

In a first embodiment, the reservoir is disposed in a bore coaxial with the bore of the damping piston.

In a second embodiment, the reservoir is located in a bore alongside and parallel to the bore of the damping piston. In this embodiment, the reservoir bore may be located above or below the damping piston bore such that the cam follower surface of the damping piston and the reservoir end cap may engage the one or more cam surfaces on the same side of the hinge axis.

The end cap may contain a spring seat to accommodate and properly align the spring.

In embodiments where the end cap is fixed, the position of the end of the spring or other resilient means remote from the pressure-reducing piston is fixed, the spring applying a constant force to the pressure-reducing piston in use.

In a variant embodiment in which the end cap is movable, the end of the spring or other elastic means remote from the decompression piston can move along the hole when opening and closing the hinge.

The end cap may directly or indirectly engage the second cam surface of the hinge shaft. The indirect engagement may be through a coupling or connecting element.

The end cap may have a cam follower surface arranged to engage the second cam surface of the hinge shaft. In this arrangement, the spring provides a variable compressive force on the liquid in the reservoir. This arrangement can absorb variations in pressure within the reservoir and the first compartment, avoiding high fluid pressures in the hinge during use.

Movement of the assembly comprising the pressure-reducing piston, the spring and the end cap provides effective control of the pressure and flow of liquid into and out of the first compartment in use. The force applied does not depend on the degree or margin of compression of the spring.

The force exerted by the hydraulic pressure urges the cam follower surface of the end cap into engagement with the cam surface of the hinge shaft to adjust the radial distance of the end cap from the axis of the hinge shaft as the hinge shaft rotates. This in turn controls the pressure applied by the spring to the decompression piston.

The pressure reducing piston applies pressure to the liquid in the reservoir to equalize the pressure in the damping interval during the opening and closing cycles of the hinge, reducing or avoiding obstructions caused by high liquid pressures within the hinge, particularly when moving to the closed position.

The one-way valve may comprise a manually adjustable needle valve. The needle valve may be arranged such that the highest liquid velocity at the closing movement of the hinge is preset when the hinge is assembled.

A needle valve may be located axially of the damping gap, the needle valve having a valve stem engaged with threads in an annular valve seat or guide communicating with the orifice and the liquid reservoir such that liquid flowing between the valve stem and the seat or guide can flow through the orifice when the hinge is closed. The one-way valve is arranged to open when the hinge is moved from the closed position to the open position and to close when the hinge is moved from the open position to the closed position. The needle valve is adjusted to control the damping force applied to the hinge. The rotatable member may comprise a collar or driver having threads extending axially through the damping piston head, which may be used, for example, for adjustment with a screwdriver at assembly. The collar or actuator may have legs with slots therebetween to receive the valve stem, allowing the valve stem to be screwed into or out of the threaded valve seat.

The damping mechanism of the present invention may be provided as a single piece that may be inserted into one or more holes in the housing and removed for repair or replacement as needed. The unitary damping member may be a sealing unit containing the operating fluid.

In addition to the adjustable hinge axis, a damping mechanism of the present invention is also provided. Such a combination may provide a convenient way to install in locations where there is no suitable construction (e.g., the wall is not vertical) without the use of padding material or other aids.

The hinge according to the invention can be used for wooden doors or glass doors, for example, internal hinges for wooden doors or shower doors. A pair of clamps may be provided to secure the door panel to the hinge. Movement of the hinge to the open or closed position moves the door to the open or closed position, respectively.

Alternatively, a door closer according to the invention having a hinged arm secured to a door frame may be conveniently secured to the top edge of a wooden or other door. In another arrangement, the hinge shaft may be mounted within the housing for rotation about an axis extending through the housing and in spaced relation to the hinge axis of the door. The description of the damping mechanism in this specification is in relation to a damped hinge, but it will be appreciated that the configuration of the damping piston and hinge shaft can be used in a door closer mechanism.

The hinge may also include a closing piston. The shutoff piston may be arranged diametrically opposite the damping piston or alternatively parallel to the damping piston and may be arranged to act on the shutoff cam surface of the hinge shaft. As a further alternative, the damping piston and the closing piston can be arranged on the hinge axis of separate hinges of the door, so that in particular in the final phase of the closing movement one hinge provides the closing force and the other hinge provides a force damping the closing movement.

In an embodiment, the damping mechanism is arranged to increase the displacement of the damping piston at the final stage of closing of the hinge. For example, the displacement of the damping piston away from the hinge shaft axis can be increased upon rotation through an incremental angle from 20o to 0o, from 10o to 0o, or from 5o to 0 o. This applies a greater pressure to the liquid displaced by the damping piston. However, the flow of the liquid is restricted by the one or more regulating valves so that a damping force is applied to the hinge shaft, thereby reducing the rotation rate and damping the movement of the door. The rotation rate of the articulated shaft decreases with the approach of the 0o position, since the damping loop imposes the maximum constraint on the liquid flow rate.

Advantageously, the configuration of the cam surface and cam follower surface (particularly the radial profile thereof) of the hinge are selected to control the distance the damping piston moves during the final angular increment as the hinge approaches the closed position.

In the first embodiment, the closing cam surface and the damper cam surface are at the same position along the axis of the hinge shaft. This arrangement reduces the torsion force applied to the hinge shaft and the bearing, and also minimizes the height of the housing.

Alternatively, in the second embodiment, the closing cam surface and the damper cam surface may be arranged at different axial positions so as to be one above the other along the hinge shaft axis within the housing. The closing piston and the damping piston may extend in parallel on the same side of the axis of the hinge shaft. Such an arrangement is disclosed in GB 2484527, the disclosure of GB 2484527 being incorporated by reference into this specification for all purposes.

In some embodiments, the closing mechanism and the damping mechanism extend radially from the hinge shaft axis in parallel directions or in opposite directions.

Drawings

The invention will be further described, by way of example and not in any limitative sense, with reference to the accompanying drawings, in which:

FIG. 1 is an exploded view of a damping mechanism according to the present invention;

FIG. 2 is an exploded view of a damping piston assembly;

FIG. 3 is a top cross-sectional view of the damping mechanism illustrating various stages of closure;

FIG. 4 is a top cross-sectional view of another damping mechanism illustrating various stages of closure;

FIG. 5 is an exploded view of another damping mechanism;

FIG. 6 is a vertical sectional view showing a closing stage of the mechanism shown in FIG. 5; and

fig. 7 and 8 are simplified cross-sectional views showing the opening and closing stages.

Detailed Description

The damping mechanism shown in fig. 1 and 2 comprises a hinge body housing (1), which hinge body housing (1) has a vertical bore (2) for receiving a hinge shaft (3) mounted in bearing rings (4, 5). The closing piston (6) is driven by a compression spring (7) acting on an end cap (8). The end cap (8) is threaded so as to close the cylindrical bore (9). The hole (9) has a horizontal axis (11), which horizontal axis (11) extends through the housing perpendicularly to the vertical hinge axis (10).

The hinge shaft (3) has a vertically extending planar closure surface (12), the planar closure surface (12) being arranged to engage the head of the piston (6) to rotate the hinge to the closed position. The hinge shaft also has a dampening cam surface (43), as shown in detail in fig. 3.

The damping mechanism comprises a sealing unit comprising a housing (13), the housing (13) having a bore and an end cap (21), the end cap (21) being threaded into the bore. A decompression piston (15) is slidably disposed in the bore. The damping piston (16) forms a fluid seal with the ring (14).

A decompression piston (15) is slidably accommodated in an axial hole of the housing (13), and the decompression piston (15) is urged toward the passage stopper (17) by a compression spring (18). The spring (18) engages into a spring seat (19) of the end cap (21). The sealing ring (20) ensures that the pressure-reducing piston (15) forms a liquid seal with the bore of the housing (13), thus forming a reservoir for oil or other working fluid.

The passage barrier (17) comprises a baffle (22), the baffle (22) extending across the bore of the housing (13), the baffle having an axial aperture (23) to allow liquid to flow between opposite sides of the baffle in use.

The non-return valve (24) comprises a valve stem (25), the valve stem (25) having a planar valve face (26), and the hollow valve stem (25) extending forwardly in a direction towards the hinge axis (10). An axial bore (37) extends through the stem (25) and the valve face (26). The flapper (22) has a planar valve seating surface arranged to engage the valve surface (26) to close the valve when liquid is pushed back off the hinge axis.

A compression spring (27) mounted on the stem (25) urges the valve face (26) into engagement with the seating surface of the flapper (22) thereby closing the valve and preventing rearward flow of liquid into the reservoir (30).

The adjustable needle valve assembly controls the flow rate of liquid through the baffle (22) between the first liquid compartment (31) and the variable volume reservoir (30), as shown in fig. 3. The needle valve comprises a conical valve stem (32) and a threaded head (33), the threaded head (33) engaging in a threaded hole (35) of an annular guide (34). The end of the valve stem (32) is housed in an axial orifice (37) of the stem (25) of the non-return valve (24). When the valve (24) is closed, the liquid flow is restricted to the volume of oil that can flow through the orifice (37) under the control of the stem (32) of the needle valve. Rotation of the needle valve head (33) in the threaded bore (35) moves the tapered rod (32) into and out of the axial bore (37) to close or open the needle valve, respectively. The driver (36) has a head with a slot (38), the slot (38) being sized to receive a screwdriver blade (not shown) or other tool. The driver further includes rearwardly extending legs (39) defining slots (40) between the legs (39). The driver is sized to be received in the bore (35) of the threaded guide (34). The screw head (38) extends through an axial bore (41) of the damping piston (16) to allow manual adjustment of the needle valve within the bore (35) when the hinge is assembled. A sealing ring (42) seals the head (38) to the damping piston (16).

When the damping mechanism is used, a reservoir comprising a housing (13), an end cap (21), a spring (18) and a decompression piston (15) is disposed within the bore (9) of the hinge body (1). Rotation of the hinge shaft (3) in the bore (2) as the hinge moves towards the closed position causes the dampening cam surface (43) to urge the cam follower surface (44) to move along the axis (11). The movement may be a forward movement towards the hinge axis (10) or a backward movement away from the hinge axis (10) depending on the rotation of the hinge axis. Rearward movement of the damping piston (16) away from the hinge axis (10) compresses the liquid in the first space (31). A check valve (24) closes an orifice (23) of the flapper (22) so that liquid can only flow through an axial orifice (37) in the needle valve and check valve stem (25). This restricts the flow of liquid and dampens the movement of the hinge as it rotates to the 0 deg. closed position.

The damping cam surface (43) has an apex (45) such that the displacement of the damping piston is maximum when the 0 ° fully closed position is reached, as shown in fig. 3 (d).

As the hinge moves from the fully closed position shown in fig. 3(d) to the 90 ° open position shown in fig. 3(a), the damping piston moves forward, reducing the pressure in the first interval, causing the check valve (24) to open under the pressure of the pressure reducing piston (15) and spring (18). Liquid can flow through the orifice (23) around the one-way valve (24), the plunger-like guide (34) allowing the hinge to open undamped.

Fig. 3(a) to (d) show successive closing phases of the hinge from a 90 ° fully open position to a 0 ° fully closed position. The parts shown in figure 3 have the same reference numerals as the parts shown in figures 1 and 2.

The damping piston (16) has a cam follower head (44) with a central rise to increase acceleration and thereby produce a damping action as the fully closed position is approached. The structure and function of the cam is disclosed in GB2501225, the disclosure of GB2501225 being incorporated herein by reference for all purposes.

In successive phases of movement from the 90 ° position to the 60 °, 30 ° and 0 ° positions, the damping piston (16) moves back (to the right as shown) away from the articulated shaft, so that the liquid is displaced, pushing it through the restricted passage between the needle valve (32) and the guide (34) and then into the reservoir (30) through the orifice (23). The elevated fluid pressure in the reservoir urges the piston (15) rearwardly to compress the spring (18) against the end cap (21).

Fig. 4 shows a modified embodiment in which the damping mechanism is a detachable independent unit. A cylindrical housing (50) encloses the damping piston (51) and the first liquid space (52), the baffle (53), the variable volume reservoir (30) and the decompression piston (15). The damping piston (51) is slidable within the bore (54) such that as the damping cam surface of the hinge shaft rotates, as shown in figures 3(a) to (d), the piston head (55) extends from the end (56) of the housing to a variable extent. The screw head (57) allows adjustment of the needle valve before fitting the unit in the hinge body or during maintenance or repair.

Fig. 5 and 6 show a further embodiment in which the damping piston and the decompression piston are disposed one above the other on the same side of the axis of the hinge shaft. The hinge housing (70) has a vertical hole to accommodate the hinge shaft (71) and the sealing rings and bearing rings (72, 73, 74, 75). Bolts (79) secure the hinge body pieces (76, 77, 78) to the housing (70).

Two parallel bores in the housing (70) accommodate a damping piston assembly and a pressure relief piston assembly, respectively.

The damping piston assembly includes: a damping piston (80), a needle valve (81), a threaded guide (82), an actuator (83), a spring (84) and a one-way valve unit as described with reference to fig. 1 to 3. The hole is closed by a closing cap (85) having an axial aperture (87), the axial aperture (87) communicating with a duct element (88) housed in a housing of a back plate (90). In a similar arrangement, the lower bore containing the variable volume reservoir is closed by an end cap (85) having an axial aperture communicating with the second end of the conduit member (88) so that liquid can flow freely between the upper and lower bores through the conduit member disposed in the seat of the back plate. This arrangement, including the ducting (88), functions similarly to the baffle (23) shown in the embodiment of figures 1 to 3. The arrangement shown in fig. 5 has the advantage that the bowl (89) has no external openings and therefore no outward leakage is possible.

The variable volume reservoir is disposed in a second lower well disposed parallel to and below the first well, as shown in fig. 5 and 6. Unlike the embodiment shown in fig. 1 to 3 or 4, the end cap (21) is replaced by a piston (91), which piston (91) is slidably movable in the bore and urged towards the axis of the hinge shaft (71) by a compression spring (92). The head (93) of the piston (91) is planar and engages the planar reservoir cam surface (94) of the hinge shaft. The reservoir cam surface (94) is at right angles to the damper cam surface (43) (fig. 1 to 3) so that when one face is fully extended, the other face is fully retracted.

In a modified embodiment (not shown), the head of the piston (91) indirectly contacts the hinge shaft through a coupling or a connection member.

The second piston (91) together with the cam surface of the hinge shaft (71) act to equalise pressure between the first gap and the adjustable volume reservoir to ensure efficient liquid flow between the gap and the reservoir during each of the open and closed periods. Avoiding high pressures within the system can extend operating life and reduce the tendency for leakage.

Fig. 7 and 8 are simplified diagrams illustrating successive opening and closing phases of the damping mechanism shown in fig. 1 to 4. For the sake of brevity and for ease of understanding, the relative proportions are varied and the springs are not shown.

Fig. 7(a) to (d) show successive opening phases, while fig. 8(a) to (d) show successive closing phases. The foregoing reference numerals have been used. Upon opening, the damping piston (16, 51) moves away from the flapper (22), increasing the volume of the first liquid space (52) and moving the conical needle valve stem (32) out of the axial bore of the stem (25) of the one-way valve. A one-way valve member (24) moves away from the seat of the flapper valve, opening the valve, thereby permitting liquid to flow into the space (52).

The rate of liquid flow through the orifice (23) of the flap (22) increases thereby reducing the damping force applied to the hinge.

In the fully open position shown in fig. 7(d), the needle valve is fully open.

When closed, as shown in fig. 8(a) to 8(d), the piston (51) moves toward the shutter (22). The check valve (24) is closed. The needle valve stem progressively engages the bore of the stem (25), restricting fluid flow and increasing the damping force to a maximum value in the fully closed position shown in figure 8 (d).

Claims

1. A damping mechanism for a hinge or door closer for controlling rotational movement of the hinge or door closer from an open position to a closed position, the damping mechanism comprising:

a housing;

a hinge shaft mounted for rotation about an axis relative to the housing;

the damping piston is installed in a hole of the housing to move about an axis perpendicular to the axis of the hinge shaft;

the damping piston includes a piston head and a piston body extending rearwardly from the piston head, the piston head extending from the bore;

the piston head is pushed forward into engagement with the cam surface;

the cam surface is configured to move the damping piston rearward away from the hinge shaft axis as the hinge moves to the closed position;

a flapper extending across said bore behind said damping piston and distal to said hinge axis, said flapper having two sides and an orifice communicating said two sides;

said aperture, piston and first side of said baffle forming a first space of liquid, the volume of said first space increasing as said piston moves toward said hinge axis and decreasing as said piston moves away from said hinge axis;

a second interval, the second interval comprising: a variable volume reservoir in communication with the orifice on the second side of the baffle; pressurizing the liquid in the variable-volume reservoir by the pressurizing means to change the volume of the variable-volume reservoir;

the damping mechanism further comprising a valve mechanism for controlling the flow of liquid through an orifice of the baffle, the valve mechanism allowing liquid to flow from the second space through the orifice to the first space; the valve mechanism allows a controllable restriction of the liquid flow from the first interval to the second interval through the orifice.

2. The damping mechanism according to claim 1, wherein the first and second spaces and any interconnecting passageway form a sealed unit in which liquid reciprocates between the first and second spaces in use.

3. The damping mechanism according to claim 2, wherein the liquid flows between the spaces through the orifice in forward and reverse directions upon the hinge opening and closing motion.

4. A damping mechanism according to any preceding claim, wherein the variable volume reservoir comprises an aperture in the housing, the aperture communicating with the second side of the barrier, the aperture being closed away from the barrier by a pressure reducing piston, the pressure reducing piston being movable within the aperture to vary the volume of the reservoir, the pressure reducing piston being urged towards the barrier by resilient means.

5. The damping mechanism of claim 4, wherein the resilient device comprises a spring.

6. The damping mechanism according to claim 4, wherein the resilient means is arranged to apply pressure to the liquid in the reservoir as the volume of the first space increases to urge the liquid into the first space as the hinge rotates.

7. A damping mechanism according to claim 4, wherein the end cap is movable, the end of the resilient means remote from the pressure relief piston being movable along the aperture as the hinge opens and closes.

8. The damping mechanism of claim 1, wherein the reservoir is disposed in a bore coaxial with a bore of the damping piston.

9. The damping mechanism of claim 1, wherein the reservoir is located in a bore that is side-by-side and parallel to the bore of the damping piston.

10. The damping mechanism according to claim 9, wherein the cam follower surface of the damping piston and the reservoir end cap engage the one or more cam surfaces of the hinge shaft.

11. The damping mechanism according to claim 7, wherein said end cap has a cam follower surface arranged to engage said second cam surface of said hinge shaft.

12. The damping mechanism of claim 1, wherein the valve mechanism comprises a one-way valve, wherein the one-way valve comprises a manually adjustable needle valve.

13. The damping mechanism of claim 12, wherein the needle valve is axially located in the damping space, the needle valve having a valve stem engaged with threads in an annular valve seat or guide in fluid communication with the orifice and the liquid reservoir; wherein the liquid flowing between the valve stem and seat or guide in use flows through the orifice when the hinge is closed.

14. The damping mechanism of claim 13, wherein the one-way valve is arranged to open when the hinge is moved to an open position and close when the hinge is moved from an open position to a closed position.

15. The damping mechanism of claim 12, further comprising a threaded member extending axially through a hole in the damping piston head.

16. A damping mechanism according to any one of claims 8 to 15, wherein the damping mechanism is a single component.

17. A hinge comprising a damping mechanism according to any preceding claim.

18. The hinge of claim 17, further comprising a closing piston.

19. A closure unit comprising a damping mechanism according to any one of claims 1 to 16.