Trunnion hinges have been known for a long time in the field of building, in particular for buildings having domestic purposes or for offices. With a trunnion hinge, a door, or other moving elements such as windows, can be rotatably suspended. With trunnion hinges, an axis of rotation of the door, around which the door is configured to be rotated during opening and closing, is thereby changed from an outer contour of the door, in the case of conventional hinges, to being an axis set at a distance thereof.

Trunnion hinges allow doors to be used without the need of a door frame. The door may, by using trunnion hinges, be suspended between a floor and ceiling. Therefore, trunnion hinges are very suitable to be used for shop entrances and in architectonic buildings.

It is however desired, in certain cases even obliged, to have self-closing doors, for example to maintain a climate in a room or, in case of a fire, to prevent the fire from expanding through the doorway.

Self-closing conventional hinges are known, which are configured to automatically bias a door into a closed position. An example such a hinge is disclosed in

WO2009/1 16700A1. Self-closing hinges are often based on the principle of accumulating energy in a spring element during opening of the door and by release of this energy during closing of the door.

In the self-closing hinge of WO2009/1 16700A1 , a screw, a nut, and a spring are provided. During opening of the door, a relative rotation between the screw and the nut is induced, which will cause the nut to translate along the screw in a downward direction. As a result of this translation, the spring is compressed elastically and elastic energy is stored therein. When the opening force on the door is removed, the spring will relax and will push the nut in the upwards direction. This upward movement will induce a relative rotation between the screw and the nut in an opposite direction as during opening, causing the door to be biased into the closed position.

These self-closing conventional hinge can, however, not be used as trunnion hinges. A first disadvantage of the self-closing conventional hinges is that the closing mechanism will only work in one opening direction and that the nut can only be moved downwards during opening of the door. Trunnion doors are configured to be opened in two directions, so a self-closing conventional hinge can therefore not be used. Secondly, most of the trunnion hinges either need to be mounted within a door or within a floor or ceiling in between which the door may be arranged. The construction of the conventional self-closing hinges is bulky, and therefore not suitable to be mounted within a door, a floor or a ceiling. Therefore, conventional self-closing hinges cannot be used as self- closing trunnion hinges.

It is an object of the invention to provide a self-closing trunnion hinge that lacks the above-mentioned disadvantages or at least to provide an alternative.

The invention provides a trunnion hinge configured to allow rotational movement of a door, window, or the like around a vertical axis with respect to a reference and to bias the door into a closed position, comprising:

an elongate spindle, extending in a vertical direction and comprising a thread on an outer surface thereof;

a housing, configured to be rotated with respect to the spindle around the vertical axis; a movable body in the housing, having a through opening, in which the spindle is received, with a thread therein, substantially corresponding to the thread of the spindle, wherein the movable body is, upon rotation of the spindle with respect to the housing, configured to move along thread of the spindle in the vertical direction; and

a spring element, configured to store and release elastic energy following from a change-in-shape thereof, induced by the vertical movement of the movable body,

wherein the housing is configured to guide vertical movement of the movable body, wherein a first one of the spindle or the housing is adapted to be fixedly mounted to the reference and a second one of the spindle or the housing is adapted to be mounted to the door, such that the vertical movement of the movable body is coupled to the rotational movement of the door, wherein the hinge is configured to store elastic energy in the spring element during opening of the door and wherein the hinge is configured to move the movable body back in the vertical direction by releasing elastic energy stored in the spring element and thereby configured to bias the door into the closed position,

characterized in that the trunnion hinge comprises at least one lever, which is pivotably mounted to the housing and is configured to transform the vertical movement of the movable body into the change-in-shape of the spring element and vice versa.

The trunnion hinge of the invention is configured to close the door when it is opened in both a clockwise and anti-clockwise direction after an opening force, used to open the door, has been removed.

The trunnion hinge is adapted to be, with a first part thereof, mounted to the door and, with a second part thereof, to be mounted to the reference, such as the floor. For example, the elongate spindle can be fixedly mounted to the floor by means of a bolted connected and a support plate. The housing may thereby be connected to the door, such that a relative rotation between the door and the floor will result in a corresponding relative rotation between the spindle and the housing.

The movable body can be slidably mounted in the housing, such that it can be moved in the vertical direction with respect to the housing. The through direction of the opening in the moving body therefor is aligned with the vertical direction as well.

The through opening comprises a thread therein, substantially corresponding to the thread of the spindle. The spindle is mounted in the housing, such that it can be rotated therein with respect to the housing round the vertical axis. Preferably, the spindle is mounted by means of a bearing, in order to reduce the amount of friction occurring during the rotation.

The bearing may be a ball bearing, but preferably is a trunnion bearing, comprising two parallel concentrically aligned discs. Both discs comprise a rolling groove, facing each other, in which balls are arranged. By the rolling contact of the balls in the grooves, relative rotation between the discs around an axis of rotation perpendicular to the plane of the discs is allowed with reduced friction as compared to when the discs were configured to slide over each other during rotation.

In an embodiment, the grooves of the trunnion bearing comprise a dimple. In case one of the balls encounters the dimple, during the relative rotation between the two discs and during rotation of the door, the balls will be pressed into the dimple, caused by the weight of the door. When the door needs to be rotated further, the ball is required to leave the dimple. However, for the ball to leave the dimple, the door has to be lifted somewhat. This lifting can only be achieved when a higher opening force is applied, as compared to the normal opening force when the ball is not arranged in the dimple.

By positioning the dimple such that the ball is in the dimple when the door is in the closed position, a larger opening force is needed to open the door from the closed position. Due to this higher force, the door can be kept in the closed position more accurately and the closing moment of the door will be higher. Furthermore, the balls within the dimples provide for a lower amount of backlash of the door in the closed position, compared to when the door were to be biased in the closed position by the spring element alone.

The pitch of the threads in the opening of the movable body and on the spindle preferably is under a relatively high angle with the tangential direction of the spindle. With common threads, having a relatively low angle, the rotation of the spindle can be

transformed into axial movement of a nut, but axial movement of the nut will not result in a rotation of the spindle due to high friction. With a relatively high pitch angle, preferably around 45° with the tangential direction of the spindle, and axial movement of the nut will result into a rotation of the spindle. In an alternative embodiment, the spindle is a rod with at least one, preferably two, grooves running along its circumference in a worm-like manner. The groove is configured to transform rotational movement of the rod into translational movement of nut, surrounding the rod, along the axis of rotation of the rod.

Alternatively, the spindle may be a hollow tube with at least one, preferably two, grooves running along its circumference in a worm-like manner.

During rotation of the door with respect to the reference, the relative rotation between the spindle and the movable body will result in a translation of the movable body in the vertical direction along the outer surface of the spindle. For example, when the relative rotation is in the clockwise direction, the movable body will move upwards, while when the relative rotation is in the anti-clockwise direction, the movable body will move downwards, or vice-versa.

The at least one lever is pivotably mounted to the housing, such that it can be rotated with respect to the housing. Preferably, the pivot point of the lever is arranged in a middle portion thereof, so that the length of the lever on both sides of the pivot point is substantially similar.

The at least one lever is configured to transform vertical movement of the movable body into a change-in-shape of the spring element and vice versa. During opening of the door, the lever is thereby rotated such that the shape of a spring element is changed, after which elastic energy is stored in the spring element. When the spring element relaxes, the elastic energy is released, inducing a rotation of the lever, which then induces closing of the door. Preferably, the change-in-shape of the spring element is a change-in-length.

Alternatively, the change-in-shape may for example be rotational deformation.

In an embodiment, the at least one lever is pivotable around a first horizontal axis. This first horizontal axis is perpendicular to the vertical axis and is, when the trunnion hinge is installed in a door, perpendicular to the plane of the door, such that the rotation takes place in the plane of the door.

In an embodiment, the at least one lever is configured to touch a contact surface on the movable body with a first end thereof. As the movable body moves in the vertical direction with respect to the housing, the first end of the lever thereby follows a contour of the contact surface.

Preferably, the contact surface is dimensioned such, that depending on the position of the movable body in the vertical direction, a horizontal distance between the contact surface and the spindle changes. As a result, during movement of the movable body with respect to the lever in the vertical direction, the first end of the lever is moved in the horizontal plane and a pivot motion of the lever is induced. The advantage of the vertically aligned lever, configured to rotate around a horizontal axis, provides the advantage over prior art hinges that the opening and closing behaviours will be obtained by vertical movement of the movable body in the plane of the door. This constructions provides that the hinge can be made relatively narrow, allowing it to be placed in thin doors. Furthermore, narrow hinges and narrow doors, can be opened to a larger angle with respect to the closed position, as compared to thicker doors with prior art trunnion hinges.

A first contact is thereby created between the first end of the lever and the contact surface of the movable body. In an embodiment, this first contact is sliding contact.

However, in alternative embodiments, the first end of the lever may be equipped with a bearing or wheel, such that the first contact is a rolling contact, which will have the advantage that friction and wear between the first end of the lever and the contact surface are reduced.

In an embodiment, a second contact is formed between a second end of the at least one lever and the spring element. The second contact is configured to transform the pivot motion of the lever into movement of the spring element, or at least into movement of an end of the spring element, and vice versa.

Preferably, the spring element is a compression spring, which is configured to store elastic energy when it is compressed. During compression, the length of the spring is decreased as a result an applied load, which will give rise to deformation of the spring, preferably only elastic deformation. The advantage of only elastically deforming the spring is that elastic deformation is fully reversible. So when the load on the spring is taken away, the spring will return to its original shape. In case the deformation in the spring were to be plastic as well, residual deformation would remain present after removal of the load.

The compression spring is furthermore configured to release elastic energy when the spring is expanded from a compressed state towards a relaxed state. The released elastic energy will induce a pivot motion, in opposite direction as during opening, of the at least one lever, ultimately resulting in closure of the door.

Preferably, the spring is arranged above the spindle and the movable body, to ensure a narrow construction of the housing. Furthermore, the spring is preferably aligned with a second horizontal axis, perpendicular to the vertical axis and the first horizontal axis, such that the change-in-length of the spring during compression and relaxation is along the second horizontal axis.

In an alternative embodiment, the spring element may be a tension spring. Such tension springs are configured to store elastic energy when their length is increased from an equilibrium length onward. A tension spring may be mounted to a portion of the at least one lever that is radially moved away from the spindle during opening of the door. In an embodiment of the hinge with a tension spring, the at least one lever may be pivotably mounted to a bottom portion of the housing with the first end. A middle portion of the at least one lever is thereby configured to follow the contact surface of the movable body. The tension spring is mounted to the second end of the at least one lever.

During opening of the door, the movable body is moved away from the equilibrium position, causing the middle portion of the at least one lever to be radially moved away from the spindle. As a result, the second end of the at least on lever is moved away from the spindle even further and the tension spring is elongated, thereby storing elastic energy.

In an embodiment, the hinge comprises a damper, which is configured to damp movements of the door. The damper thereby is arranged such, that it is configured to apply a force parallel, but in opposite direction, to the force applied by the spring element.

Preferably, at least when the spring element is a spiral compression or tension spring, the damper can be arranged within the coils of the spring. By doing so, empty space in between the windings of the spring is effectively used.

In an embodiment, the spring has a constant stiffness, independent of its length. As such, the force required to compress the spring, the resilience, increases linearly with the change-in-length of the spring, and the elastic energy stored in the spring scales to the power two with the change-in-length.

In alternative embodiments, the stiffness of the spring increases or decreases with change-in length. For example in the case of increasing stiffness, the resilience may scale with the change-in-length to the power two and the stored elastic energy may scale with change-in-length to the power three.

In an embodiment, the hinge has two levers, which are pivotably mounted to the housing. The two levers are arranged on opposite sides of the movable body. The two levers are thereby arranged in the same plane, preferably the door plane, having axes of rotation perpendicular to the plane, parallel to the first horizontal axis.

The movable body comprises a respective contact surface for each of the two levers, arranged on opposite sides of the movable body as well, each facing a first end of a lever, in order to form a first contact with the first ends of each of the levers.

As a result hereof, during movement of the movable body, the rotation of the two levers is in opposite direction. During opening of the door, for example, the spring element is thereby compressed from two sides, by the second ends of both levers.

In an embodiment, in the closed position of the door, the movable body is in an equilibrium position on the spindle. This equilibrium position preferably is arranged halfway the spindle, in a middle portion thereof, such that the movable body can be moved upwards and downwards from the equilibrium position during opening of the door in two directions. The contact surface thereby is shaped such, that when the movable body is in the equilibrium position, the first contact point is arranged the closest to the spindle in an equilibrium point. The first end of the at least one lever is thereby as close to the spindle as possible, such that the second end of the at least one lever is projected away from the spindle as far as possible. The length of the spring element is, because of the second end of the at least one lever facing away from the spindle, the largest and the spring element is relatively relaxed.

The equilibrium position of the movable body on the spindle is, in an embodiment of the hinge, chosen such that when the door is opened from the closed position, the movable body is vertically moved away from the equilibrium position along the spindle. Depending on the direction in which the door is opened, the movable body is thereby configured to move in an upward direction or in a downward direction.

Furthermore, when the door is biased into the closed position by the hinge, the movable body is moved back towards the equilibrium position along the spindle. This back movement is in the opposite vertical direction as compared to the direction in which the movable body was moved during opening of the door.

In an embodiment, the contact surface is shaped such that, during the vertical movement of the movable body away from the equilibrium position, it is configured to horizontally move the first end of the lever away from the spindle. Thereto, the distance between the spindle and the contact surface in the horizontal plane increases with increasing distance in the vertical direction between the movable body and the equilibrium position.

Preferably, but not necessarily, the movable body is symmetrical along the horizontal plane through the equilibrium point, such that the path of the first end of the at least one lever along the contact surface is similar during the vertical movement of the movable body in the upwards and in the downwards direction.

In an embodiment, the vertical movement of the movable body towards the equilibrium position, during which the door is biased to the closed position, is induced by the first end of the lever, which is horizontally moved towards the spindle by the expanding spring element. The shape of the contact surface thereby transforms this inward movement of the first end into a movement of the movable body along the spindle towards the equilibrium position.

In an embodiment, the contact surface is progressive, such that a distance between the spindle and the first end of the lever increases progressively with an increasing distance between the position of the movable body on the spindle and the equilibrium position. As such, for example in case the spring element has a constant stiffness, the force required to open the door increases progressively. During the onset of opening, when the movable body is just moved away from the equilibrium position, the required opening force is relatively low. When the door, however, is almost fully opened, the required force to continue opening becomes relatively high.

This progressive force development is convenient for the closing of the door, since the required force to close the door is highest on the onset of moving the door away from the opened position.

In an alternative embodiment, the contact surface is regressive, such that a distance between the spindle and the first end of the lever increases regressively with an increasing distance between the position of the movable body and the equilibrium position.

Alternative contact surfaces may as well be made of combination of a progressive and a regressive shape in order to obtain the desired opening and closing characteristics of the hinge.

In an alternative embodiment, the shape of the at least one lever can also be changed to change the opening and closing characteristics of the hinge.

The advantage of having different profiles for the contact surface is that the opening and closing characteristics of the hinge can be adapted, preferably to optimally suit certain requirements, which may be prescribed by for example building norms.

For example, the profile can be adapted in order to obtain a certain closing moment of the door. With this closing moment, it is provided that the door will remain in the closed position when an opening force, being lower than a certain threshold value, is applied. Alternatively, the opening and closing characteristics may be adapted to the size and mass of the door.

To obtain different opening and closing characteristics, different types of springs may also be applied. It can be imagined that a spring with a relatively low stiffness will be less suitable for relatively large doors and vice versa.

Prior to installing the movable body and the spring element, a computer simulation may be performed in which the dimensions and other properties of the door are entered and in which the desired opening and closing characteristics are entered. Based on these parameters, the computer model is thereby configured to select the optimal type of spring element and the movable body having the best possible contact surface profile.

In an embodiment, the contact surfaces of the moving body comprise flat portions at upper and lower ends thereof. At these flat portions, the contact surfaces extend

substantially vertical. The flat portions are arranged such, that when the door is opened, the first end of the at least one lever contacts the contact surface at these flat portions.

The compressed spring element is configured to close the door, but because the flat portions are aligned with the vertical direction, the movable body is not forced to vertically move along the spindle towards the equilibrium position. As a result, the door will remain in the opened position, despite the closing force of the compressed spring element. In an alternative embodiment, the flat portions may be arranged at a middle portion of the moving body, in between the upper and lower ends. By doing so, the door can be, depending on the position of the flat portion on the movable body, prevented from closing at any desired opening angle.

The invention further provides a door assembly comprising a door and at least one trunnion hinge, as claimed in any of the claims 1 - 15. The door is thereby suspended above a floor with the at least one hinge, such that a substantial gap remains present between the door and the floor.

The at least one hinge in the door assembly is configured to allow rotational movement of the door around a vertical axis with respect to a reference and to bias the door into a closed position. With the provision of the trunnion hinge, a door frame is no longer required to suspend the door from, since the trunnion hinges provide for example for a suspension from a floor.

The door is configured to be, outgoing from the closed position, opened into two directions. During opening of the door, the hinge is configured to store elastic energy in a spring element, after which, when the elastic energy is released by the spring element during relaxation of it, the door is biased into the closed position.

In an embodiment of the door assembly, the spindle of the at least one hinge is fixedly mounted to the floor and the housing of the at least one hinge is fixedly mounted at least partially within the door. Since only the spindle has to be fixedly mounted to the floor, no, or at least little, adaptions have to be done to the structure of the building in order to install a door assembly with the self-closing trunnion hinge. This is in particular convenient when such a door assembly were to be installed in an existing building.

In an alternative embodiment of the door assembly, the housing of the at least one hinge is fixedly mounted at least partially in the floor and the spindle of the hinge is fixedly mounted to the door. This alternative configuration provides the advantage that most parts of the hinge are hidden within the floor and that a so-called clean-looking door assembly is obtained. Due to the relatively large amount of components have to be installed within the floor, this configuration may be best suitable for newly-built buildings, since, during design of these buildings, the locations for these hinges can readily be taken into account.

The invention further provides a method for assembling a trunnion hinge as claimed in any of the claims 1 - 15, comprising the steps of:

providing a spindle, at least one lever and a housing;

determining, based on the dimensions of a door, which is to be suspended from the hinge, opening and closing characteristics of the door;

selecting, based on the determined characteristics, a suitable spring element and a suitable movable body. The method provides the advantage that the opening and closing characteristics of the hinge can be adapted, while not all the parts of the hinge need to be replaced. In the method, the spindle, the at least one lever and the housing may be standard components which are similar for all different types of trunnion.

By selecting a suitable spring element and a suitable movable body, the opening characteristics and closing characteristics of the hinge can be altered, while the spindle, the at least one lever and the housing remain the same.

As such, a relatively cheap method of assembling hinges is created, since the usage of certain standard components may reduce the fabrication costs and transportation costs as well.

In an embodiment of the method, the suitable spring element is selected from multiple spring elements having different dimensions and/or a different stiffness. By choosing the suitable spring element, the opening and closing characteristics of the door can be adapted, for example to take specific dimensions of the door into account.

In an embodiment of the method, the suitable movable body is selected from multiple movable bodies having different dimensions and/or different contact surface profiles. By choosing the suitable movable body, the closing moment of the door and/or the

development of the opening force as a function of the opening angle of the door, can, for example, be altered.

In an embodiment of the method, the step of selecting is performed by means of a computer program. The program may thereby select the suitable spring element and/or the suitable movable body, based for example on required opening and closing characteristics of the door, dimensions of the door and/or closing moment of the door.

The use of a computer program, rather than by manually selecting, will provide the advantage that more variables may be taken into account upon selecting. Furthermore, the suitable spring element and/or suitable movable body may be selected from more possible candidates when the computer program is used, as compared to when the suitable spring element and/or suitable movable body were to be selected manually.

An embodiment of a trunnion hinge according to the invention will now be described in further detail, by way of example only, with reference to the accompanying drawings, in which:

Figure 1A shows, in side view, an embodiment of a trunnion hinge according to the invention, mounted at least partially in a door, wherein the door is in the closed position;

Figure 1 B shows a cross-sectional view on the embodiment of the trunnion hinge with the door in the closed position; Figure 2 shows a cross-sectional view on the embodiment of the trunnion hinge with the door opened, rotated 90° to one side; and

Figure 3 shows a cross-sectional view on the embodiment of the trunnion hinge with the door opened, rotated 90° to the other side.

Figure 1A shows a side view on an embodiment of a trunnion hinge according to the invention, denoted by reference numeral 1. The hinge 1 is configured to allow rotational movement of a door 100 with respect to a reference 1 1 and to bias the door 100 into a closed position, as displayed in figure 1A.

The hinge 1 comprises a spindle 10, a housing 20, a movable body 30 within the housing 20 and a spring element 40. The spindle 10 is fixedly mounted to the reference 1 1 by means of a base plate 12, such that no relative movement is allowed between the spindle 10 and the reference 1 1.

The spindle 10 is rotatably mounted within the housing 20, such that the housing 20 can be rotated around a vertical axis (V). The movable body 30 is slidably mounted within the housing 20, such that it is configured to move in the vertical direction (V) with respect to the housing 20.

In figures 1 B, 2 and 3, a cross-sectional view on an embodiment of the hinge according to the invention is displayed. The movable body 30 comprises a through opening 31 , extending in the vertical direction (V) having a thread 32 therein. The spindle 10 is received in the through opening 31 and a thread 13 of the spindle 10 substantially corresponds to the thread 32 of the movable body 30. As a result of the corresponding threads 13, 32, relative rotation between the spindle 10 and the housing 20 is transformed into vertical movement of the movable body 30 in the housing 20.

The spring element 40 is a spiral compression spring 40, which is substantially aligned with a second horizontal direction (H"), perpendicular to the vertical direction (V) and extending parallel to the plane of the door 100. As such, compression and relaxation of the spring 40 will be caused by a change-in-length of the spring 40 along the second horizontal direction (H").

The spring 40 is configured to store and release elastic energy. When the spring 40 is compressed, elastic energy is stored in the spring 40. When the spring 40 is relaxed, the stored elastic energy is released again and the spring 40 will return towards its original length.

In figure 1 B, a cross-sectional view on the hinge 1 is displayed from the same direction as in figure 1A.

The hinge 1 comprises two levers 50, which are mounted to the housing 20 on opposing sides of the moveable body 30. The levers 50 are rotatably mounted in pivot points 51 and are rotatable around a first horizontal axis (Η'), perpendicular to the vertical direction (V) and the second horizontal direction (H").

A first end 52 of the lever 50 is configured to follow a contact surface 33 of the movable body 31 with a rolling wheel 53. A second end 54 of the lever 50 is connected to the spring 40 by a connection piece 55.

In an alternative embodiment, the first end of the lever may follow the contact surface as a sliding contact. However, sliding contacts are prone to more wear than a rolling contact, so it is preferred to have a rolling contact between the first end of the lever and the contact surface of the movable body.

During vertical movement of the body 30, the orientation of the levers 50 will change due to the non-vertical contact surfaces 33. As a result of the rotation of the levers 50, the length of the spring 40 is changed.

During opening of the door 100, elastic energy is stored in the spring 40, as the result of compression of the spring 40. Elastic energy is released by the spring 40 during closing of the door 100, as a result of the relaxation and increasing length of the spring 40.

In figures 1A and 1 B, the door 100 is in the closed position and the movable body 30 is in an equilibrium position. When the movable body 30 is in the equilibrium position, it is arranged on a middle portion of the spindle 10. Outgoing from the equilibrium position, the body 30 can be vertically moved both in the upward and downward direction, depending on the rotation of the spindle 10.

The contact surfaces 33 are shaped such, that when the movable body 30 is in the equilibrium position, the first ends 52 of the levers 50 contact the contact surfaces 33 of the movable body 30 in an equilibrium point 34. When the first ends 52 are in the equilibrium point 34, the horizontal distance between the spindle 10 and the first ends 52 of the levers 50 is the shortest.

At the same time, the length of the spring 40, extending between both connection pieces 55 of the second ends 54, is therefore the largest possible and the spring 40 is relaxed.

In figure 2, the hinge 1 is displayed with the door 100 opened into a first opened position. In the first opened position, the door is rotated 90° degrees around the vertical axis (V). During opening of the door 100 from the closed position towards the first opened position, the movable body 30 is vertically moved upwards as a result of the relative rotation between the spindle 10 and the housing 20. During the upwards movement of the body 30, the first ends 52 of the levers 50 are moved outwards, away from the spindle 10, due to the non-vertical contact surface 33. The levers 50 thereby compress the spring 40 with the second ends 54 during rotation around the pivot points 51. To open the door 100, an opening force must be applied in order to compress the spring 40. When the door 100 is intended to be closed from the first opened position, the opening force is taken away after which the spring 40 will relax. During relaxation of the spring 40, the second ends 54 of the levers 50 are, seen from the spindle 10, pressed outwards. The levers 50 are rotated in opposite direction to the rotation during opening, forcing the first ends 52 of the levers 50 to move inwardly, towards the spindle 10. Since the first ends 52 are then pressed against the contact surfaces 33, the movable body 30 will be pressed down along the spindle 10. Finally, this downward movement of the body 30 will induce a relative rotation between the spindle 10 and the housing 20, resulting into closure of the door 100.

On upper end portions 35 and lower end portions 36 of the movable body 30, the contact surface 33 extends substantially parallel to the vertical direction (V). These vertical portions 35, 36 provide that the movable body 30 will not be pressed down by the second ends 54 when the door 100 is rotated more than 90° from the closed position.

In certain cases, it can be convenient to keep a door 100 in an opened position, for example when a large number of people need to pass through. When the door 100 needs to be closed, a small closing force can be applied, resulting in the second ends 54 of the levers 50 to contact the non-vertical parts of the contact surface 33, after which the door 100 is biased to the closed position by the relaxing spring 40.

When the door 100 is in the first opened position, the rolling wheels 53 of the lever 50 are pressed against the lower end portions 36 of the movable body 30. Since the force, which is induced by the spring 40, of the first end 52 of the lever 50 on the contact surface 33 at the flat portions 35, 36 has no component parallel to the vertical direction (V), the body 30 will not be moved and the door 100 will remain in the opened position.

In the present embodiment, the shape of the contact surface 33 is substantially linear, so the outward movement of the first ends 52 of the levers 50, following the contact surface 33, is linear with movement of the movable body 30 along the spindle 10, away from the equilibrium position.

In an alternative embodiment, the contact surface may be progressive or regressive, wherein the rate of outward movement of the levers respectively increases or decreases with movement of the movable body, away from the equilibrium position.

In figure 3, the hinge 1 is displayed with the door 100 opened into a second opened position. In the second opened position, the door is rotated -90° degrees around the vertical axis (V). In the second opened position, the door 100 is under an angle of 180° with the door being opened into the first opened position.

When the door 100 is opened into the second opened position, the relative rotation between the spindle 10 and the housing 20 is in the opposite direction as during opening into the first opened position. The movable body 30 will, during opening into the second position, be moved downward from the equilibrium position, as can be seen in figure 3.

The movable body 30 is symmetrical about a horizontal plane (M), so the profile of the contact surface 33 is similar on both sides of the plane (M). The spring 40 will therefore, during opening of the door 100 into the second opened position, be compressed in a similar manner as when the door 100 were to be opened into the first opened position. When the door 100 is in the second opened position, the rolling wheels 53 of the lever 50 are pressed against the upper end portions 35 of the movable body 30.

The closing of the door 100 from the second opened position is similar, but in opposite direction, to the closing of the door from the first opened position. The movable body 30 will be moved in the upward direction, as a result of the inward movement of the first ends 52 of the levers 50, induced the relaxation of the spring 40.

The hinge 1 is adapted to be mounted inside the door 100 with its housing 20. The housing 20 is thereby inserted in a slot, which is provided in an underside of the door 100. The door 100 is supported by a support plate 21 , which projects away from the housing 20 in the horizontal plane.

In an alternative embodiment, the housing is fixedly mounted within a floor. The weight of the door and the hinge is then supported by the support plate, which is adapted to be mounted in the floor.

The hinge 1 comprises a ball bearing 22 to allow for rotation of the housing 20 around the spindle 10. In alternative embodiment, a plain bearing may be provided.

However, a ball bearing 22 is preferred due to the lower amount of frictional losses, compared to plain bearings.