GB2512751A - Damped self-centering hinge - Google Patents

Abstract

A self-returning damped hinge comprising: a housing 3 having a bore 11 in which is rotatably mounted a spindle 6; within the housing is mounted a closing arrangement 14 which includes a closing piston 18 with projection 19 spring biased into contact with a first centering cam surface 26 on the spindle to urge the spindle into a first position, e.g. closed or centered, and a damping arrangement which includes a working fluid and a damping piston 32 with projection 44 biased into engagement with a second centering cam surface 45 on the spindle to damp the rate at which the spindle rotates toward the first position; the damping piston and closing piston guided for movement radially of the spindle. The damping piston head has a non-return valve allowing fluid flow from a second chamber 39 defined by an external face of the piston, spindle and bore to a first chamber 38 defined by an internal face of the piston, and cylinder 34, preferably a fluid return channel 41, 42, includes an adjustment screw 40. The contact surface of one or both of the pusher and piston is convex to reduce wear. The spindle may have stop surfaces to hold a door in an open position.

Description

DAMPED SELF-CENTERING HINGE.

F This invention relates to a hinge for a door, particularly for a glass door, particularly but not exclusively for a frameless glass door.

Frameless glass doors are often heavy and may be double or triple glazed, particularly when intended for exterior usc or for chilled rooms. Such doors may be heavy, requiring use of a robust hinge which provides reliable self-closing of the door to a centred closed position, avoiding the need for a latch or stop arrangement.

Frameless glass doors having internal door stops have been disclosed, for example in US 6560821. W020 11/020630 discloses a glass door hinge having an internal door stop arrangement comprising: a housing; a mount for coupling the housing to a support member; a pair of clamps; an axial spindle; and a plurality of biasing members arranged to engage the spindle to return the clamps to one of a plurality of positions selected from a closed position and one or more open positions; wherein the spindle has a plurality of centering surfaces, each biasing member being arranged to apply a force to a respective centering surface to centre the hinge in one or more of the positions. The disclosure of this specification is incorporated by reference for all purposes into the disclosure of the present

specification.

According to the present invention, there is provided a door hinge having a self-centering internal door stop arrangement comprising: a housing having a vertical bore; a mount for coupling the housing to a support member; a pair of clamps; a spindle mounted within the bore; a closing arrangement within the housing and adapted to engage the spindle to urge the hinge to a closed or centred position; so a damping arrangement within the housing and adapted to engage the spindle to damp movement of the hinge toward the closed position; wherein the spindle has a vertical axis and first and one or more second centering cam surfaces, the centering surfaces being arranged to urge the closing and damping arrangements alternately away from the axis as the housing rotates in relation to the spindle respectively away from or towards the closed position; wherein the closing arrangement comprises a closing member having a pusher head having at least one closing contact surface and a spring, the spring being arranged to urge the contact surface into engagement with the first centering surface; wherein the damping arrangement comprises working fluid and a piston, the piston comprising a piston head and a sleeve slidably mounted within a cylinder, a spring located within the cylinder, the piston having a projection with a damping contact surface, the damping contact surface being urged by the spring into engagement with a second centering surface of the spindle; the damping piston including a non-return valve; wherein the closing and damping arrangements extend radially from the spindle axis in opposite directions; wherein an interior surface of the damping piston, sleeve and cylinder form a first chamber and the exterior surface of the damping piston head, bore and spindle form a is second chamber for working fluid; working fluid disposed in the second chamber passing through the non-return valve in the damper piston as the damper piston moves towards the spindle axis in use, return flow through the non-return valve being prevented as the damper piston moves away from the spindle axis.

The hinge is preferably for use with a glass door, more preferably a frameless glass door. Movement of the clamps to an opened or closed position correspondingly moves the door to an opened or closed position. The centering surfaces, particularly the first centering surface act as cam surfaces as the member is rotated during opening or closing of the door.

In preferred embodiments an adjustable valve is located in the housing; a first duct communicating between the first chamber and the adjustable valve; a second duct communicating between the second chamber and the adjustable valve; whereby adjustment of the valve controls flow of working fluid from the first chamber to the second chamber to damp movement of the hinge towards the closed or centred position.

Use of a single adjustable valve is preferred. However, two or more adjustable valves may be used, if desired.

s A hinge in accordance with the present invention confers several advantages. Use of two separate closing and damping arrangements allows each of them to be manufactured with a simple and robust construction so that the closing and damping forces and the damping profile may be selected to suit any particular application. For example, a stronger damping arrangement may be used for a heavy door or a large door which may be io easily slammed during use.

The location of the damping arrangement on the opposite side of the spindle to the closing arrangement provides a more balanced construction in comparison to hinges in which both closing and damping pistons are on the same side of the spindle axis. Wear of the bearings is reduced so that misalignment of the cam surfaces is less likely to occur after prolonged use. This is particularly important where there are relatively small secondary or intermediate cam surfaces (if present as described below), since the edges of these cam surfaces may become worn if the spindle is not accurately aligned.

The working fluid is preferably oil or hydraulic fluid.

The damping arrangement may comprise a circuit for working fluid extending from the chamber in which the spring is located to the adjustable valve, and from the adjustable valve to the chamber in which the exterior front surface of the damping piston engages the cam or centering surface of the spindle. The moving parts may be therefore maintained in a well lubricated condition.

A single adjustable valve may be located on the exterior of the housing permitting simple and convenient adjustment.

The closing arrangement, located in a separate chamber within the housing, may be filled with oil or other fluid, although this is not essential. When a piston arrangement is used, one or more apertures may be provided to permit circulation of the working fluid as the piston extends and retracts in use. The aperture may be dimensioned to restrict the flow of fluid in order to provide additional damping for the hinge. Alternatively, the aperture may be sufficiently large to permit a free flow.

The first and second centering cam surfaces may have a similar or different configuration. In preferred embodiments, the surfaces are approximately semicircular in radial cross-section. Preferably the planar portions extend forwardly of the spindle axis so that the axis passes through the spindle and does not pass through the space in front of the planar surface. Secondary stop surfaces perpendicular to the planar surfaces may be provided. This permits the hinge to be stopped at an open position, for example 900 from the closed centred position. Such an arrangement is not feasible if the closing member extends beyond the spindle axis in the centred position.

The or each stop surface may be arranged to engage the main closing member to hold the clamps of the hinge in an opened position. Preferably the hinge is held in an opened position perpendicular to the closed position.

Preferably the or each stop surface is perpendicular to the first centering cam surface.

Preferably two parallel stop surfaces are provided. There are preferably two open positions perpendicular on either side of the closed position. In this arrangement the door may be held in an open position perpendicular on either side of the closed position. A door attached to the hinge may be held open in either direction unless a small closing force is applied to the door sufficient to overcome the force of the main spring.

In the following description a direction towards the biasing member or piston is referred to as proximal and a direction away from the closing member or piston towards the spindle is referred to as distal.

In a preferred embodiment the spindle is arranged so that when the first centering earn surface is facing proximally towards the closing member, the or each stop surface extends perpendicularly relative to the centering surface, the stop surface having a proximal edge facing towards the closing member and a distal edge facing away from the closing member.

In this position the stop surface preferably extends from a location distally of the spindle axis either to a location proximally of the spindle axis, or to a location on the axis io that is on the diameter of the spindle parallel to the first centering surface. In the latter arrangement, wherein the or both proximal edges are located on the spindle diameter in the closed position, the proximal edge is orthogonal to the spindle diameter, the or each stop surface preferably extends distally of the spindle axis. In this arrangement the hinge is prevented from angular rotation beyond the angle of the opened position, due to abutment between the closing member and the stop surface. Rotation of the hinge towards the closed position is facilitated by the closing member contacting the proximal edge of the stop surface before engagement with the first centering surface.

In an alternative embodiment the proximal edge is located proximally of the spindle diameter. In this arrangement the stop surface preferably extends proximally by a sufficient distance to provide a restoring force to resist rotation of the hinge towards the closed position. The distance between the proximal edge and the diameter (or spindle axis) may be selected so that the closing member provides a restoring force sufficient to allow a door secured to the hinge to be held in the opened position but with the force not being so large that a user would have difficulty in closing the door. The magnitude of the distance and consequently of the restoring force may depend on the width of the door, the weight of the door and the strength of an intended user.

In preferred embodiments the first centering cam surface is located proximally of the spindle diameter. This confers several advantages. Closing of the hinge is facilitated.

The length of the extension of the spring or other closing member in use is reduced. This permits use of a more powerful but less expensive spring. The volume of lubricating oil displaced during rotation of the spindle is reduced. This provides a longer working life for the oil.

A further cam surface may be provided between the proximal edge of the stop surface and an adjacent edge of the first centering surface. The further cam surface may be rounded to facilitate smooth opening and closing of the hinge, reducing wear of the contact s surface. This permits use of a Lower grade of steel for manufacture of the spindle.

One or more intermediate surfaces may be provided between the first and second centering cam surfaces, the or each being located at an angle intermediate the first and second surfaces. The intermediate surfaces may be planar or convex and may serve to impede or prevent closure of the hinge at an intermediate angle. In such an arrangement, accidental slamming of a door may be prevented. The intermediate surfaces may be at an angle of 300, 45° or 600 to the first closing centering cam surface. The engagement of the closing member with the intermediate surfaces may reduce the rate of rotation of the door or may allow the door to be halted at the intermediate angle.

The clamps may be adapted to securely engage a glass door panel. The glass panel may have holes to receive bolts passing through the clamps. Alternatively or in addition the clamps may engage the glass panel by friction or by use of an adhesive.

The hinge includes damping means for damping the opening and closing movements of the hinge. The closing means includes a damping arrangement to limit the rate of rotation of the hinge particularly from the opened to the closed position. The damping means may also limit the rate of rotation from a partially opened position to a fully opened position. 4 In a first preferred embodiment the hinge includes a secondary biasing member and a secondary spring arranged to engage one or more secondary centering surfaces to urge the door into one of two opened positions.

The or each secondary centering surface may be a planar or cylindrically concave surface.

Alternatively the secondary centering cam surface may comprise a cylindrical member parallel to and displaced from the spindle axis. Use of a cylindrical surface has the advantage that smooth damping is achieved with low wear of the moving parts. The cylindrical member preferably located within the circumference of the spindle.

The two biasing members are integral within a single unit and have a common spindle.

Preferably the two opened positions of the hinge are perpendicular to the closed position, and the two secondary centering cam surfaces are orthogonal to the first centering cam surface and are diametrically opposed to each other. That is the secondary surfaces may be arranged to face in opposite directions perpendicular to the first centering cam surface.

The force of the main spring is preferably greater than the force of the secondary spring. In this way the hinge moves to the closed position unless the door is at or adjacent either of the opened positions. The hinge therefore may comprise an overcentre arrangement * wherein it moves either into the closed position or an open position when opened in either direction. The angular location of each centre point on each side of the closed position is preferably close to the opened position. * 44

The main spring may comprise a pair of concentric springs. The outer spring may 4*O*ee * be a relatively powerful spring to provide the closing force for the hinge. The inner spring may be relatively less powerful than the outer spring and is arranged to provide a closing force for a non-return valve in the face of the closing member. The non return valve is described further below.

Each biasing member may comprise a piston mounted in a cylindrical bore for movement radially with respect to the spindle.

The closing member may comprise a piston slidably moveable within a cylinder, the piston comprising a pusher head and a sleeve, preferably a cylindrical sleeve. The pusher head may have a projection with one or more contact surfaces. A spring may be located within the sleeve and arranged to engage a rear surface of the piston head to urge the contact surface into engagement with the centering surface of the spindle.

The spindle may be mounted in a vertical guideway in the housing, the guideway communicating with one or more passageways within which the or each of the closing members are located to allow circulation of hydraulic fluid or other oil during actuation of the hinge.

In a preferred embodiment, the spindle comprises an axially extending member having a first cam centering surface and one or more damping cam centering surfaces disposed in axially spaced relation to the closing cam centering surface; and a barrier between the closing and damping cam centering surfaces extending towards the surface of the bore to substantially prevent fluid flow between the closing and damping cam centering surfaces in use.

The fluid flow is preferably prevented to a sufficient extent that an increase in fluid pressure on one side of the barrier does not cause a sufficient increase in fluid pressure on the other side of the barrier to reduce the closing force exerted by the piston of the closing member.

However, a sufficient separation between the barrier and the bore may be provided to allow for lubrication by the fluid.

The barrier may comprise a cylindrical collar extending radially from the spindle to a location adjacent the surface of the bore.

The first or cam centering surface may be parallel to the contact surface of the piston in the fully extended position of the piston.

The diameter or width of the first or cam centering surface is preferably less than the diameter of the cylindrical collar or other barrier. The diameter of the closing cam centering surface may be from 70% to 98%, preferably from 80% to 98%, more preferably 85% to 95% of the diameter of the collar. Use of a smaller diameter or width reduces the extent of compression of the closing spring or springs. Consequently the friction and wear of the closing surfaces is reduced.

s In a preferred embodiment the piston of the or each closing means includes a non-return valve arranged to pennit a flow of oil into the cavity as the piston and cylinder expand. In this way oil is circulated from the cavity of the piston into a cavity between the piston and spindle and back into the piston cavity during the compression and expansion cycle of the piston. During this cycle the volume of the cavity available between the centering cam surface of the spindle and piston increases as the piston is compressed and decreases as the piston expands to filly engage the centering surface. This change in volume serves to pump oil through the non-return valve to cause circulation of the oil during opening and closing of the hinge and door. Circulation of the oil contributes to efficient damping of the hinge.

The main piston may be provided with one or more apertures to allow a flow of oil from the cavity during initial compression of the piston.

In a preferred embodiment the piston has a head and a cylindrical body dimensioned to be slidably received within a cylindrical bore of the sleeve, and one or more apertures provided at a predetermined axial distance from the head, the aperture or apertures being blocked by the sleeve after sliding of the body by a predetermined distance into the cylindrical sleeve. In this arrangement oil can flow easily from the piston cavity until the piston has retracted to a predetermined extent, after which flow of oil is impeded or prevented, thereby providing a two speed damping effect.

The main non-return valve may be urged distally into a closed position by the inner spring of the main biasing means. The length of the inner spring may be selected to provide an appropriate closing force to the valve. Preferably the inner spring has a greater length than the outer spring.

The damping piston may have a sleeve with one or more cutaway portions providing one or more passageways extending along the exterior of the sleeve to a location at the end of the sleeve communicating with the internal cavity to provide differential damping dependent on the extension of the damping piston. The cross-sectional area of the passageway or passageways may vary along the length of the sleeve, for example, increasing away from the spindle so that a smaller cross-sectional area for fluid flow is provided as the sleeve and piston head are compressed away from the spindle axis. Fluid flow through the passageway or passageways may be prevented as the damping piston approaches a fully compressed position. The contact surface of the projection may be concave or cylindrical to provide a shallow depression. This may serve to prevent adhesion to the cam surface of the spindle. Irregularities in the cam surface may form during prolonged use. The cam surface may be planar or curved. Use of a concave or cylindrical surface may be beneficial to ensure smooth and unimpeded contact between the surfaces as the hinge rotates. Excessive compression of the spring is avoided reducing frictional forces between the moving parts. Use of a concave area on the piston pushing head provides several advantages. The concave surface helps in damping when the door to which the hinge is mounted closes. Good contact with the spindle is ensured if the centre contact surface of the spindle has become rough or uneven due to wear. Further, the concave surface is used to release the compression of the closing spring. When the hinge opens, this reduces the friction when a door is opened to 75° to 85°. The concave area may provide a recess for any residue to accumulate such as may occur during long term Use.

The contact surface may comprise a central portion and two outer portions, the central portion being located axially in relation to the spindle axis, the length of the central portion from the piston head being longer or shorter than the length of the outer portions from the piston head.

In a first embodiment the central portion is longer extending further towards the spindle so that the contact surface is generally convex.

In an alternative embodiment the central portion is shorter so that the contact surface is generally concave or inwardly curved.

The central and outer portions may be independently either curved or planar and may form a continuous or discontinuous axially symmetrical contact surface. For example a smooth concave or convex surface may be provided. Alternatively a stepped configuration may be provided.

Selection of an appropriate profile for the contact surface in combination with the configuration of the centering cam surfaces allows control of the closing or damping forces applied during rotation of the hinge in use.

In alternative embodiments, the contact surface may be convex or extend cylindrically outwardly.

A convex or outwardly extending surface may be helpful to maintain the spring under compression to enable a door to withstand strong winds without being blow-n open.

The housing and base may be arranged to allow for easy installation of a heavy or large door. In a preferred embodiment the housing may have a curved protrusion, for example a rounded protrusion, preferably having a partially spherical male portion dimensioned to be received into a complementary rounded formation, for example a partially spherical recess of thc basc on which the hinge is mounted.

Alternatively the protrusion may be elliptical or otherwise curved in plan view.

Use of such an arrangement allows the protrusion to be located within the socket during installation followed by more precise alignment as the weight of the door is released into engagement with the mount.

The invention is further described by means of example, but not in any limitative sense, with reference to the accompanying drawings, of which: Figure 1 is a perspective view of a hinge in accordance with the invention; Figure 2 is a cross-sectional view of a hinge; Figure 3 is a perspective view showing the damping piston; Figure 4 is a perspective view showing the closing piston; Figure 5 is a perspective view of the spindle; Figure 6 shows the mounting arrangement of the hinge; Figure 7 is an exploded view of the hinge; Figure 8 is a series of cross-sectional views showing the cam surface and closing piston at various angles; and Figure 9 to 17 show various constructions of closing members.

In the following description, the same reference numerals are used to denote the same components in the various figures.

Figure 1 shows a perspective view of a hinge in accordance with this invention. A io pair of clamps (1) mounted on housing (3) form a channel (4) within which a glass door panel (not shown) may be engaged.

A base plate (2) serves as a support member arranged to be secured to a floor or ground surface (not shown). A mount (5) may be secured within the base plate (2) as shown in Figure 6 permitting easy assembly of a door unit.

Figure 2 shows a cross-sectional view of the hinge. Spindle (6) extends axially, vertically within the hinge body. The spindle (6) is received within a blind bore (11) within the housing (3), the bore having a closed upper end (12). Gaskets (13) seal the spindle and bore, preventing leakage of working fluid in use. A square fixing lug (7) at the lower end of the spindle is received in a correspondingly shaped socket of the mounting (5), preventing rotation of the spindle in use. Bearings (9,10) permit rotation of the housing (3) around the spindle axis.

A closing arrangement (14) is mounted in a generally cylindrical chamber (15) in the housing (3), extending radially from the bore (11). The chamber (15) is closed by a cylinder (16) having a threaded end cap. A first closing piston comprising a cylindrical sleeve (17) and a piston head (18) is slidably received within the cylinder (16). The piston head (18) has a projection (19) extending radially through an aperture (20) from the chamber (15) into the bore (11). A pair of coiled springs (2 1,22) extend between the end cap of the cylinder (16) and the rear surface of piston head (18) to urge the contact surface (25) of the projection (19) into engagement with the spindle (6).

A cylindrical collar (31) extends radially from the spindle to a circumference adjacent the inner surface of the bore (11). The clearance between the collar (31) and bore (11) is sufficient to allow passage of lubricating fluid but sufficiently small to prevent fluid pressure from being transmitted from one side of the collar to the other during the period in which a door is opened or closed during normal use.

The cavity between the spindle and the bore is therefore divided into two, upper and lower parts. The lower chamber (23) communicates via aperture (20) with the forward part of chamber (15) located radially inwardly of the piston head (18). Aperture (24) permits flow of working fluid past the piston head as the piston head moves radially inwardly in or outwardly during use. The upper chamber (30) similarly communicates with the cylindrical damping chamber within which the damping piston is housed, as described below.

The contact surface (25) of the projection (19) is received in a socket defined by the lower surface of collar (31), the upper surface of an additional lower collar (27) and a generally planar cam surface (26) of the spindle (6). The cam surface (26) extends parallel to the contact surface (25) of projection (19), radially outwardly of the spindle axis so that the contact surface does not extend beyond the axis during use.

Planar stop surfaces (28) extend vertically perpendicular to the cam surface (26) as shown in Figure 5. Two stop surfaces are preferably provided. These serve to hold a door open during use.

Opening of the door causes the hinge body to rotate relative to the spindle.

Rotation from the closed centred position causes projection (19) to rotate relative to cam surface (26) urging the projection and piston radially outwardly to compress the springs (21,22). During the movement of the piston, working fluid within the chamber (15) flows radially inwardly through the aperture (24) in the piston head into the cavity in front of the piston head between the bore and spindle.

When the door is opened to 900 the hinge will remain open due to engagement of the end of the projection with the perpendicular stop surface (28). A slight pressure on the door is sufficient to release the hinge, following which the springs urge the housing to rotate relative to the spindle, causing the door to return to a closed centred position without application of frirther manual effort.

One or more intermediate stop surfaces (53) may he provided, as shown in Figure 5. The intermediate stop surfaces located at an angle intermediate between the main cam surface (26) and perpendicular stop surface (28) cause a damping force to be exerted in the event that the door is closed quickly.

The width or diameter of the planar cam surface (26) is less than the diameter of the collars (27) or (31). Preferably the diameter of each of the cam surfaces is less than the diameter of the collars (27), (31)or (49) to reduce the wear on the components in use. The diameter of the surface (26) may be 70% to 98%, preferably 80% to 98%, more preferably 85% to 95% of the diameter of the collar (27). The reduced diameter serves to reduce the distance between the secondary stop surfaces (28), consequently reducing the extent to which the closing springs (21,22) are compressed in the fully opened position of the hinge.

The closing force exerted by the closing piston is reduced so that friction and long term wear between the contact surface (25) and the surfaces (28) are also reduced.

The damping arrangement is located in a damping chamber (29) extending radially in an opposite direction to the closing arrangement (14). The damping chamber may be axially offset in relation to the closing chamber.

A piston comprising a piston head (32) and cylindrical sleeve (33) is mounted for slidable movement in a cylinder (34). A one-way, non-return valve comprises a seat (35) and a valve stop (36) located within the piston. An aperture (37) in the valve head allows passage of working fluid between the first chamber (38) within the piston and the second chamber (39) radially inwardly of the piston head (32). Fluid may flow from the second chamber (39) to the first chamber (38) through the valve (35,36); but flow from the first chamber (38) to the second chamber (39) is prevented by closure of the valve (35,36).

A projection (44) having a radially inwardly facing contact surface (45) extends from the piston head (32). The contact surface (45) may be planar, slightly concavc or have a central cylindrical depression and is arranged to engage one of two planar cam surfaces (46) on the spindle.

The cam surfaccs (46) extend parallel on opposite sides of the spindle axis and are perpendicular to the closing cam surface (26) of the spindle. Stop surfaces (47) extend perpendicularly to the cam surface (46). Secondary stop surfaces (48) extend between the cam surfaces (46) and stop surfaces (47) at an intermediate angle, for example 600, 45° or 30° to the cam surfaces.

In an alternative embodiment, the contact surface may be convex or have an outwardly cylindrical depression.

An upper collar (49) serves with the collar (31) and cam surfaces (46) to define a socket (50) to receive the projection (44) as the hinge is rotated. Rotation of the hinge housing around the spindle as a door is opened or closed causes the closing and damping pistons to be compressed or allowed to expand dependant on the orientation of the respective cam surfaces relative to the projections of the pistons. As the closing piston is compressed, the damping piston is allowed to expand to cause the working fluid to flow radially outwardly from the chamber (39) into the chamber (38) in which the fluid is in contact with the spring, so that the fluid is largely located within the piston.

Cylinder (34) has an aperture (43) communicating with a first duct (41) extending from the chamber (29) to a first side of an adjustable screw valve (40) located in a bore in the exterior of the housing (3). A second duct (42) extends from a second side of the adjustable valve (40) to the second chamber (39). When the screw valve is opened working fluid may flow from the first chamber (38) to the second chamber. Partial closure of the valve restricts the fluid flow, damping the motion of the piston and preventing rapid closure of the door.

As the door is manually closed or is released to allow closure due to the force of the springs (21,22), the damping piston is compressed. The spring (51) has a weaker force than the springs (21,22). Spring (51) serves to damp the opening and closing movements of the hinge by restraining opening of the hinge by compression of the spring. During opening further damping may be provided by the frictional force of the spring. A pair of springs may be provided, a weaker spring having a longer extension to maintain the damping force over the entire range of movement of the piston.

Fluid pressure within the first chamber (38) increases and the one-way valve (35,36) is closed preventing passage of fluid through the valve. Due to the increase in pressure, fluid is forced though the aperture (43) in the cylinder and into the duct (41) within the housing (3). Fluid passes through the duct (41) to a first side of the screw valve and into duct (42) which returns the fluid to the damping chamber (29) of the damping arrangement, radially inwardly of the piston head, in the vicinity of the spindle as shown in Figure 2. Adjustment of the aperture of the screw valve limits the maximum rate of fluid flow through the valve, so that increased pressure within the chamber (38) restricts the closing or centering movement of the hinge.

The outer surface of sleeve (33) is provided with a cutaway portion (52) to form a passageway allowing fluid flow from the first chamber (38) to the aperture (43) and valve (40). The cross-sectional area of the passageway may vary along the axial length of the sleeve, decreasing radially inwardly relative to the spindle so that a smaller cross-sectional area for fluid flow is provided as the sleeve (33) and piston head are compressed and move away from the spindle.

Fluid flow is restricted and may be prevented as the damping piston reaches a fully compressed position. In this way the damping force is increased as the hinge nears the frilly closed or centred position. The closing movement of the hinge is reduced and may be halted as the fully closed or centred position is reached.

During opening of the hinge, an increase in fluid pressure in second chamber (39) is caused by the pressure of the spring (51) and the piston head (32). Fluid is prevented from flowing into the operating chamber of the closing arrangement due to the proximity of collar (31) to the interior surface of the bore (11).

In this way fluid is retained in the second chamber (39) and passes through the non-return valve (35,36). This ensures an adequate amount of fluid to create sufficient pressure in the first chamber (38) during the return stroke to force the fluid through the circuit defined by the adjustable valve (40) and ducts (4 1,42).

Figure 6 illustrates the mounting arrangement. During assembly the base plate (2) is fastened to the floor using bolts or other fastenings. The mount includes a slot (70) having a partially spherical central socket (71). In alternative embodiments the central socket may be elliptical or ovoid in plan view. The mount (5) has a correspondingly shaped elongate member (74) and a central generally part spherical, elliptical or ovoid protrusion (75). The protrusion (75) is configured to fit within the socket to allow the mounting with a door attached to be aligned as it is released into the socket (70,71) during assembly.

Figure 8 illustrates an alternative configuration of the piston and spindle. In use, particularly over a prolonged period, the centering surface of the spindle may be come worn and irregular. This may create friction when the door opens to 60-80° due to the compressive force of the spring. In order to address this problem, the contact surface (60) of the projection (61) of the piston (62) may be formed with a concave or cylindrical surface as shown in Figure 8. Use of a concave or surface with a cylindrical depression allows a reduction in the amount of compression of the spring since the projection is not moved radially outwardly (downwardly as shown in Figure 8) to such an extent as with a planar contact surface. This reduces the extent to which the closing springs are compressed in the fully opened position of the hinge.

3D In a preferred embodiment, outer portions of the contact surface are planar with a central portion being concave or cylindrical. This assists in reducing the closing speed as the fully closed or centred position is approached.

In a 900 position, the spindle touches the concave cylindrical bottom of the piston.

When thc angle is moved to 85° the self-closing operation of the hinge commences and continues as the angle moves through 60° and 45° to 30°. When the angle reaches 30° the contact surface of the projection (61) changes from a concave or cylindrical shape to a planar shape (63). When the angle reaches 15° the cam surface of the spindle is in sliding engagement with the planar surface (63) so that the closing speed is reduced. In the flilly closed position at 0 degrees the spindle touches both planar portions (63) of the projection (61).

Since the extension of the spring brackets (not shown) in the piston is reduced in relation to an embodiment in which the contact surface is completely planar, not having a concave cylindrical portion, the friction between the piston and spindle is reduced.

is Figure 9 to 17 show various constructions of the biasing members comprising pistons with pusher heads.

Figure 9 shows piston of a biasing member comprising a piston head (80) having a rearward or proximally extending cylindrical sleeve (81) and a rear end (82). The rear end is open to receive the spring (not shown). A projection (83) offset from the axis of the cylindrical sleeve (81) extends forwardly from the piston head (80) and has a flat or planar contact surface (84) arranged to engage a centering cam surface of the spindle (not shown).

In use the piston moves radially inwardly or outwardly with respect to the spindle axis due to engagement with the cam surface against the restoring force provided by the spring.

Figure 10 shows an alternative piston having a contact surface with a cylindrically concave axial portion (85) located between a pair of flat or planar outer portions (86). The cylindrically concave central portion (85) serves to reduce frictional forces due to compression of the spring (not shown), in order to reduce wear on the moving parts on so prolonged use.

Figure 11 shows a further alternative wherein a flat or planar central portion (87) is located between two shoulders (89) and flat or planar outer portions (88). In this arrangement the central portion (87) extends from the piston head (90) by a shorter distance than the outer surfaces (88) in order to reduce frictional forces at the maximum compression of the spring.

Figure 12 shows a further alternative embodiment wherein the cylindrically S convex central portion (81) extends at a greater distance from the piston head (93) than two flat or planar outer portions (92).

Figure 13 a further embodiment is shown. A planar axial central portion (94) is located between two shoulders (95) and planar outer portions (96). The central portion Ia (94) of the contact surface extends a greater distance from the piston head (97) than the outer portions (96).

Figure 14 shows a further embodiment in which a continuous cylindrically convex contact surface (98) extends across the entire width of the projection (99).

Figure 15 shows a piston similar to that shown in Figure 9 wherein a V-shaped slot (100) into sleeve (103) extends from an intermediate position (101) on the sleeve to a rearward the opening end (102). The cross sectional area of the slot (100) increases from the forward point (101) towards the end (102) so that the flow of oil increases as the piston moves forwardly towards the spindle within the axial bore (not shown).

Figure 16 shows a further embodiment in which the sleeve (104) has a flat sector (105) removed therefrom to provide a channel from a forward point (106) to an opening at the rear end of the sleeve (107). The cross sectional area of the channel increases rearwardly from the point (106) to the end of the sleeve (107) allowing a greater flow of oil as the piston extends towards the spindle in use.

Figure 17 shows a further embodiment in which the sleeve (108) has a V-shaped slot (109) extending from an intermediate portion and to an opening at the rear end of the so piston. The piston head (110) has a projection (111) extending forwardly to form a contact surface (112). The contact surface (112) has a central axial planar portion (113) with sloping portions (114) on either side extending to outer planar portions (115) formed on the outer edges of the projection (111). In this way the contact surface extends to a maximum distance axially of the piston and spindle (not shown) and is formed with shorter projecting portions (115) on each outer side.

Claims (14)

1. CLAIMS1. A door hinge comprising: a housing having a vertical bore; a mount for attachment to a support member; a pair of clamps; a spindle mounted within the bore; a closing arrangement within the housing and adapted to engage the spindle to urge the hinge to a closed or centred position; a damping arrangement within the housing and adapted to engage the spindle to damp movement of the hinge toward the closed position; wherein the spindle has a vertical axis and first and one or more second centering cam surfaces, the centering cam surfaces being arranged to urge the closing and damping arrangements alternately away from the axis as the housing rotates in relation to the spindle respectively away from or towards the closed position; wherein the closing arrangement comprises at least one closing contact surface and a closing member having a spring, the spring being arranged to urge the contact surface into engagement with the first centering cam surface; wherein the damping arrangement comprises working fluid and a piston, the piston comprising a piston head and a sleeve slidably mounted within a cylinder, a spring located within the cylinder, the piston having a projection with a damping contact surface, the damping contact surface being urged by the spring into engagement with the second centering cam surface of the spindle; wherein one or both contact surfaces is convex; the damping piston including a non-return valve; wherein the closing arrangement and damping arrangement extend radially from the spindle axis in opposite directions; wherein an interior surface of the damping piston, sleeve and cylinder form a first chamber and the exterior surface of the damping piston head, bore and spindle form a second chamber for working fluid; working fluid disposed in the second chamber passing through the non-return valve in the damper piston as the damper piston moves towards the spindle axis, return flow through the non-return valve being prevented as the damper piston moves away from the spindle axis.
2. 2. A hinge as claimed in claim 1, wherein the contact surface is a continuous convex surface.
3. 3. A hinge as claimed in claim 1 or 2, wherein the convex contact surface extends across the entire width of the projection.
4. 4. A hinge as claimed in any preceding claim, wherein a convex central portion of the contact surface extends a greater distance from the piston than two outer portions.
5. 5. A hinge as claimed in any preceding claim, further comprising an adjustable valve located in the housing; a first duct communicating between the first chamber and the adjustable valve; a second duct communicating between the second chamber and the adjustable valve; whereby adjustment of the valve controls flow of working fluid from the first chamber to the second chamber to damp movement of the hinge towards the closed or centred position.
6. 6. A hinge as claimed in claim 5 wherein the adjustable valve is located on the exterior of the housing.
7. 7. A hinge as claimed in any preceding claim wherein the closing member further comprises a piston slidably movable within a cylinder, the piston comprising a sleeve, the pusher head having a projection, the spring being located within the sleeve arranged to engage a rear surface of the piston to urge the contact surface into engagement with the centering surface of the spindle.
8. 8. A hinge as claimed in any preceding claim wherein the first centering cam surface of the spindle is disposed in axially spaced relation to the one or more second centering cam surfaces; a barrier between the closing and damping cam surfaces extending radially from the spindle to a location adjacent the surface of the bore to substantially prevent fluid flow between the cam surfaces in use.
9. 9. A hinge as claimed in claim 8 wherein the barrier comprises a cylindrical collar extending radially from the spindle adjacent to the bore.
10. 10. A hinge as claimed in any preceding claim, wherein a contact surface of the closing arrangement is concave or cylindrical.
11. 11. A hinge as claimed in claim 9, wherein a diameter of the first centering cam surface is from 70% to 98%, preferably 80% to 98%, more preferably 85% to 95% of a diameter of the collar.
12. 12. A hinge as claimed in claim 11 wherein the diameter of the first centering cam surface is from 80% to 90% of a diameter of the collar.
13. 13. A hinge as claimed in claim 12 wherein the diameter of the first centering cam surface is from 85% to 95% of a diameter of the collar.
14. 14. A hinge substantially as hereinbefore described with reference to the accompanying drawings.Amendments to the claims have been filed as followsCLAIMS1. A door hinge comprising: a housing having a vertical bore; a mount for attachment to a support member; a pair of clamps; a spindle mounted within the bore; a closing arrangement within the hc*using and adapted to engage the spindle to urge the hinge to a closed or centred position; a damping arrangement within the housing and adapted to engage the spindle to damp movement of the hinge toward the closed position; wherein the spindle has a vertical axis and first and one or more second centering cam surfaces, the centering cam surfaces being arranged to urge the closing and damping arrangements alternately away from the axis as the housing rotates in relation to the spindle respectively away from or towards the closed position; wherein the closing arrangement comprises a closing member having a pusher head having at least one closing contact surface and a spring, the spring being arranged to urge ? the contact surface into engagement with the first centering cam surface; wherein the damping arrangement comprises working fluid and a piston, the piston a.. 20 comprising a piston head and a sleeve slidably mounted within a cylinder, a spring located * as * within the cylinder, the piston having a projection with a damping contact surface, the damping contact surface being urged by the spring into engagement with the second centering cam surface of the spindle; wherein one or both contact surfaces is convex; the damping piston including a non-return valve; wherein the closing arrangement and damping arrangement extend radially from the spindle axis in opposite directions; wherein an interior surface of the damping piston, sleeve and cylinder form a first chamber and the exterior surface of the damping piston head, bore and spindle form a second chamber for working fluid; working fluid disposed in the second chamber passing through the non-return valve in the damper piston as the damper piston moves towards the spindle axis, return flow * 25 through the non-return valve being prevented as the damper piston moves away from the spindle axis.2. A hinge as claimed in claim 1, wherein the contact surface is a continuous convex surface.3. A hinge as claimed in claim 1 or 2, wherein the convex contact surface extends across the entire width of the projection.4. A hinge as claimed in any preceding claim, wherein a convex central portion of the contact surface extends a greater distance from the piston than two outer portions.5. A hinge as claimed in any preceding claim, further comprising an adjustable valve located in the housing; a first duct communicating between the first chamber and the adjustable valve; a second duct communicating between the second chamber and the adjustable valve; whereby adjustment of the valve controls flow of working fluid from the first chamber to the second chamber to damp movement of the hinge towards the closed or centred position.6. A hinge as claimed in claim 5 wherein the adjustable valve is located on the exterior of the housing.7. A hinge as claimed in any preceding claim wherein the closing member further comprises a piston slidably movable within a cylinder, the piston comprising a sleeve, the pusher head having a projection, the spring being located within the sleeve arranged to engage a rear surface of the piston to urge the contact surface into engagement with the centering surface of the spindle.8. A hinge as claimed in any preceding claim wherein the first centering cam surface of the spindle is disposed in axially spaced relation to the one or more second centering cam surfaces; * 26 a barrier between the closing and damping cam surfaces extending radially from the spindle to a location adjacent the surface of the bore to substantially prevent fluid flow between the cam surfaces in use.9. A hinge as claimed in claim 8 wherein the barrier comprises a cylindrical collar extending radially from the spindle adjacent to the bore.10. A hinge as claimed in any preceding claim, wherein a contact surface of the closing arrangement is concave or cylindrical.11. A hinge as claimed in claim 9, wherein a diameter of the first centering cam surface is from 70% to 98%, preferably 80% to 98%, more preferably 85% to 95% of a diameter of the collar.12. A hinge as claimed in claim 11 wherein the diameter of the first centering cam surface is from 80% to 98% of a diameter of the collar. *fle*afls.* 13. A hinge as claimed in claim 12 wherein the diameter of the first centering cam surface is from 85% to 95% of a diameter of the collar.14. A hinge substantially as hereinbefore described with reference to the accompanying * drawings ***** *