Device for closing a hinged member

Abstract

A closing device includes an actuator mechanism and a hydraulic damper mechanism. The actuator mechanism includes a pushrod urged by a resilient member towards its extended position. The hydraulic damper mechanism includes a piston, a first rack and pinion gearing for converting the translational motion of the pushrod into a rotational motion of a first pinion, a transmission, which includes a second rack and pinion gearing, between the first pinion and the piston for transmitting and converting the rotational motion of the first pinion into a translational motion of the piston, a one-way valve allowing fluid flow from a first side to a second side of the cylinder cavity when opening the hinged member, and a restricted fluid passage between the first and second sides of the cylinder cavity. The transmission provides together with the pinions of the first and second rack and pinion gearings a reduction gearing between the pushrod and the piston so that the piston reciprocates over a smaller distance than the pushrod.

Claims

1. A device for closing a closure member hinged on a support, which closing device comprises an actuator mechanism having a resilient member which is arranged to urge the hinged closure member towards its closed position and a hydraulic damper mechanism for damping the closing movement of said hinged closure member under the action of said resilient member, which actuator mechanism comprises: a frame; a reciprocating pushrod which is slidably mounted on said frame to translate between an extended and a retracted position when opening and closing the hinged closure member; and said resilient member which is arranged between said pushrod and said frame to urge the pushrod towards its extended position, and which hydraulic damper mechanism comprises: a cylinder barrel defining a closed cylinder cavity; a reciprocating piston placed within said cylinder barrel so as to divide the cylinder cavity into a first side and a second side; a first motion converting mechanism for converting the translational motion of said pushrod into a rotational motion of a first pinion, which first motion converting mechanism comprises a first rack and pinion gearing having a first rack on said pushrod which engages said first pinion; a transmission, including a second motion converting mechanism, between said first pinion and said piston for transmitting and converting the rotational motion of said first pinion into a translational motion of the piston; a one-way valve allowing fluid flow from said first side to said second side of the cylinder cavity when opening the hinged member; and at least one restricted fluid passage between said first and second sides of the cylinder cavity, wherein: the hydraulic damper mechanism comprises a piston rod fixed to said piston to reciprocate together with the piston in the cylinder cavity; said second motion converting mechanism comprises a second rack and pinion gearing arranged within said cylinder cavity and having a second rack formed by said piston rod and a second pinion engaging said second rack; and said transmission provides together with said first and second a reduction gearing between said pushrod and said piston so that said piston reciprocates over a smaller distance than said pushrod.

2. A closing device according to claim 1, wherein at least at 20° C., said piston has a diameter which is smaller than the diameter of said cylinder cavity at the location of the piston so that a clearance is present between the piston and an inner surface of the cylinder barrel, said at least one restricted fluid passage comprising said clearance.

3. A closing device according to claim 2, wherein said cylinder barrel is made of at least a first material and the piston of at least one second material which is selected to have such a thermal expansion coefficient, different from the thermal expansion coefficient of said first material, that the surface area of said clearance decreases when the temperature of the damper mechanism increases from 20° C. to 30° C. and increases when the temperature of the damper mechanism decreases from 20° C. to 10° C.

4. A closing device according to claim 1, wherein said first motion converting mechanism is arranged outside the closed cylinder cavity.

5. A closing device according to claim 1, wherein said transmission comprises a rotary shaft which enters said closed cylinder cavity in said first side thereof.

6. A closing device according to claim 5, wherein said second pinion is provided on said rotary shaft.

7. A closing device according to claim 5, wherein said rotary shaft is provided outside the closed cylinder cavity with a first gear which has a pitch diameter which is larger than the pitch diameter of said second pinion.

8. A closing device according to claim 7, wherein said first gear is different from said first pinion and is coupled thereto, the first gear preferably engaging said first pinion.

9. A closing device according to claim 1, wherein said reduction gearing has such a gear ratio that the distance over which said piston reciprocates is at least 1.5 times smaller than the distance over which said pushrod reciprocates.

10. A closing device according to claim 1, wherein said piston has a diameter which is larger than 20 mm.

11. A closing device according to claim 1, wherein said piston has a diameter which is smaller than 70 mm.

12. A closing device according to claim 1, wherein said reciprocating pushrod is slidably mounted on said frame between two extreme positions determining a maximum stroke of the pushrod and said reduction gearing has such a gear ratio that when the pushrod is moved over its maximum stroke the amount of hydraulic liquid displaced by the piston is comprised between 1.0×D ml and 3.0×D ml, which amount is preferably larger than 1.5×D ml and smaller than 2.5×D ml, with D being the diameter of the piston in mm.

13. A closing device according to claim 1, wherein said cylinder barrel is made of extruded aluminium and comprises at least one non-circular longitudinal through hole which is arranged to receive said second rack.

14. A closing device according to claim 1, wherein the frame of the actuator mechanism comprises a first hinge part arranged to be hinge connected to one of said hinged member and said support and the pushrod comprises a second hinge part arranged to be hinge connected to the other one of said hinged member and said support.

15. A closing device according to claim 1, wherein said resilient member comprises a helical spring.

16. A closing device according claim 1, wherein the closing device comprises a main body which is made in one piece of an extruded aluminium profile and which forms a portion of the frame, of the hydraulic damper mechanism and a portion of the actuator mechanism.

17. A closing device according to claim 16, wherein the cylinder cavity is cut in said piece of extruded aluminium profile.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other particularities and advantages of the invention will become apparent from the following description of some particular embodiments of the closing device according to the present invention. The reference numerals used in this description relate to the annexed drawings wherein:

(2) FIG. 1 is a perspective view on an embodiment of the closing device according to the present invention mounted on a garden gate which is suspended by means of so-called 180° hinges on a fixed post;

(3) FIG. 2 is a top plan view on the closing device and the garden gate illustrated in FIG. 1;

(4) FIG. 3 is a front elevation view on the closing device and the garden gate illustrated in FIG. 1;

(5) FIG. 4 is a same view as FIG. 2 but with the gate in the open instead of in the closed position;

(6) FIGS. 5 to 8 are the same views as FIGS. 1 to 4 but show the closing device mounted on a garden gate suspended by means of so-called 90° hinges on the fixed post;

(7) FIG. 9 is an enlarged view on the closing device mounted on the garden gate as illustrated in FIGS. 5 to 7 wherein the lid and the housing of the closing device are shown in a transparent way to show the internal parts of the closing device;

(8) FIG. 10 shows a front elevation view on the closing device itself;

(9) FIG. 11 is a longitudinal sectional view in elevation through the middle of the closing device, indicated by arrows XI-XI in FIG. 12;

(10) FIGS. 12 and 13 are longitudinal sectional views indicated by arrows XII-XII and XIII-XIII in FIG. 10;

(11) FIGS. 14 to 16 are the same views as FIGS. 11 to 13 but show the closing device in its compressed instead of its extended position, i.e. with the garden gate onto which it is mounted in its open instead of in its closed position;

(12) FIG. 17 is a same view as FIG. 11 but on a larger scale and showing only the hydraulic damper mechanism with a part of the actuator mechanism; and

(13) FIGS. 18 to 20 are also on a larger scale cross-sectional views indicated by arrows XVIII-XVIII, XIX-XIX and XX-XX in FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

(14) The closing device of the present invention is a device for closing a closure member 1 hinged on a support 2. The closure member 1 can be a door, surrounded by a door frame acting as support for the door, but the closure member 1 of the present invention is especially intended for gates. Gates are normally not surrounded by a frame in contrast to a door which is surrounded by a door frame which also extends above the door. The support 2 of a gate may for example be a post fixed onto or into the ground or a wall or another part of a fence. The closing device is an elongated device having one of its two extremities hingedly mounted, by means of a first bracket 12, onto the support 2, more particularly on the front side thereof, and having its other extremity hingedly mounted, by means of a second bracket 13, onto the hinged closure member 1. Both extremities of the closing device are respectively provided with a first hinge part 40, which is arranged to co-operate with the first bracket 12, and with a second hinge part 41, which is arranged to co-operate with the second bracket 13. The axis of the hinges 11 of the closure member and the hinge axis of the closing device on the support do not coincide so that the closing device is compressed when the closure member is opened and is extended when the closure member is closed.

(15) The closing device comprises an actuator mechanism 3, which has a resilient member 4 arranged to urge the hinged closure member 1 towards its closed position, and a hydraulic damper mechanism 5 for damping the closing movement of the hinged closure member 1 under the action of the resilient member 4. The closing device 3 preferably comprises a main body 6 which is made in one piece of an extruded aluminium profile and which is provided with two end caps 7 covering the two extremities of the aluminium body 6 and with a cover 8.

(16) The use of an extruded aluminium profile has several advantages compared to a main body which is die cast from an aluminium alloy. First of all extruded aluminium can be anodized to protect it against corrosion, in contrast to die cast aluminium. Moreover, die cast aluminium comprises air inclusions so that it is porous as a result of which hydraulic liquid may leak out of the hydraulic cylinder. In practice, it has been found that up to 50% of die cast hydraulic cylinders have to be discarded because they are not sufficiently impervious. To avoid such air inclusions vacuum die cast installations can be used but they are much more expensive thus increasing the manufacturing costs. Compared to die cast aluminium, extruded aluminium is moreover less brittle and hence less prone to breaking, especially at the location where the telescopic arm is mounted onto the aluminium body, for example when somebody would step on this telescopic arm. As explained hereinafter, the main body forms both a part of the actuator mechanism 3 and of the damper mechanism 5 so that both mechanisms are strongly and reliably connected to one another by the single piece of extruded aluminium profile.

(17) The actuator mechanism 3 of the closing device illustrated in the figures is a telescopic mechanism which comprises, as can be seen for example in FIG. 11, a frame 9, a reciprocating pushrod 10 which is slidably mounted on this frame 9 and the resilient member 4 arranged between the pushrod 10 and the frame 9. The reciprocating pushrod 10 can translate between two extreme positions, namely between the maximally extended position, illustrated in FIGS. 11 to 13 and the maximally retracted position, illustrated in FIGS. 14 to 16. The pushrod 10 moves between an extended and a retracted position when opening and closing the hinged closure member 1. These two positions correspond either to the two extreme positions of the pushrod 10 or are situated between these two extreme positions so that the maximum stroke of the piston rod 10 is not always used. The distance between the extended and the retracted position of the pushrod 10 depends on the relative positions wherein the closing device and the closure member 1 are hingedly mounted on the support 2.

(18) The maximum stroke of the pushrod 10 is preferably larger that 100 mm, more preferably larger than 120 mm and most preferably larger than 140 mm, for example 160 mm. Due to such a large maximum stroke, the positions wherein the closing device is mounted on the hinged closure member 1 and on the support 2 thereof (which may depend for example on the diameter or thickness of the support) has a smaller effect on the functioning of the closing device. Moreover, different types of hinges 11 can be used, for example so-called 180° hinges, illustrated in FIGS. 1 to 4, and so-called 90° hinges, illustrated in FIGS. 5 to 8. As can be seen in FIG. 2, a 180° hinge is mounted on the front side of the support 2 whilst, as can be seen in FIG. 6 a 90° hinge is mounted on the lateral side of the support 2 facing the hinged closure member 1 in its closed position. Since the closing device is hingedly mounted also on the front side of the support 2, the bracket 12 used for hingedly mounting the closing device on the support 2 is longer for a 180° hinge than for a 90° hinge. The closing device is thus very versatile and provides a certain freedom as to the exact mutual mounting position of the closing device 1 on the support 2 with respect to the hinge axis of the hinged closure member 1.

(19) The resilient member 4 of the actuator mechanism 3 illustrated in the drawings is a helical compression spring. Alternatively, a pneumatic spring (i.e. an air spring) could be used or also a tension spring or even a torsion spring but a compression spring enables the most compact and reliable mechanism. A compression spring is also the most compact solution for enabling a large stroke of the pushrod 10. An advantage of a larger stroke is that more energy can be stored in the resilient element without having to increase the spring constant, i.e. a weaker spring can be used which generates less stresses in the device and on the hinges or the brackets 12, 13 by means of which the closing device is hingedly mounted onto the support 2 and on the hinged closure member 1.

(20) The frame 9 of the actuator mechanism 3 comprises first of all a portion of the aluminium body 6 of the closing device. This portion comprises a longitudinal circular hole 14, which is extruded and which is arranged to slidably receive the pushrod 10. The pushrod 10 has a circular cross-section which fits in this longitudinal hole 14 and part of which has been cut away to form a toothed rack 15. The frame 9 of the actuator mechanism 3 further comprises a tube 16, which is preferably made of stainless steel, and which is mounted, in particular flanged, around the portion onto the aluminium body 6 which forms the longitudinal hole 14 to extend the longitudinal hole 14 wherein the pushrod 10 slides. The distal extremity of the pushrod 10 is provided with a cap 18 onto which a larger tube 17, which slides telescopically over the projecting part of the tube 16, is mounted. The tube 16 has a larger inner diameter than the longitudinal hole so that the helical compression spring 4 can be applied in the tubes 16 and 17 around the pushrod 10. The compression spring 4 is compressed between the aluminium body 6 and the cap 18 on the distal extremity of the pushrod 10 to urge the pushrod towards its extended position. The force exerted by the spring 4 can be adjusted by means of a set screw 19, shown in FIG. 12, which enables to change the position of the cap 18 on the pushrod 10.

(21) The hydraulic damper mechanism 5, illustrated on a larger scale in FIG. 17, comprises a cylinder barrel 42 which defines a closed cylinder cavity 20. The cylinder barrel 42 is formed by the aluminium body 6 which has a longitudinal, rectangular extruded hole 21. This hole is enlarged on one side by a cutting process to make the cylinder wherein the piston 22 reciprocates. This enlarged hole is closed off by means of an oil plug 23 provided with seal rings. The other end of the rectangular hole 21 is also cut to obtain an enlarged cylindrical hole and is screw threaded to be closed of by means of an oil plug 24 which is also provided with seal rings. In contrast to rotating seals, such static seals enable a perfect sealing of the cylinder cavity 20.

(22) The piston is provided with a one-way valve 25 which allows flow of hydraulic liquid from a first side 26 to a second side 27 of the cylinder cavity 20 when the hinged closure member 1 is opened. Within this one-way valve 25 is a safety valve 28 which enables flow of hydraulic liquid from the second side 27 of the cylinder cavity 20 to the first side 26 thereof when the pressure in the second side 27 of the cylinder cavity 20 exceeds a predetermined threshold level, in particular when an excessive force is exerted onto the hinged closure member 1 to close it. This additional force can be exerted thereon by a person or by the wind. The safety valve 28 protects the closing device in such a case from getting damaged.

(23) After having opened the hinged closure member 1, it is automatically closed again by the action of the compression spring 4 urging the pushrod 10 to its extended position and hence the closure member 1 to its closed position. The closing movement is damped by the piston 22 moving towards the second side 27 of the cylinder cavity 20. To enable flow of hydraulic liquid from the second side 27 to the first side 26 of the cylinder cavity 20, at least one restricted fluid passage is provided between these two sides of the cylinder cavity. One restricted fluid passage being formed by a channel 29 (see FIG. 9) connecting in all the possible positions of the piston 22, i.e. in all the positions between its two extreme positions, the first side 26 of the cylinder cavity 20 with the second side 27 thereof. This channel 29 is provided with an adjustable valve 30, in particular a needle valve, so that the flow of hydraulic liquid through this channel 29 can be controlled, in particular depending on the mounting position of the closing device, i.e. depending on the distance over which the pushrod is moved when opening and closing the hinged closure member 1.

(24) A further restricted fluid passage is provided by making the diameter D of the piston 22, at least at 20° C., somewhat smaller than the diameter of the cylinder cavity 20. This further restricted fluid passage is thus formed by the clearance 43 between the piston 22 and the inner surface of the cylinder barrel 42. The closing movement of the closure member 1 is thus damped due to the fact that the hydraulic liquid can only flow through the two restricted fluid passages.

(25) In the embodiment illustrated in the figures, a further restricted fluid passage 31 is provided to allow flow of hydraulic liquid from the second side 27 of the cylinder cavity 20 to the first side 26 thereof when the closure member 1 is nearly closed. This further restricted fluid passage 31 forms a by-pass which causes an increase of the closing speed at the end of the closing movement to ensure that the closure member 1 is reliably closed. The flow of hydraulic liquid through this further restricted fluid passage 31 is adjustable by means of a further adjustable valve 32.

(26) To couple the piston 22 to the pushrod 10 so that both move together, the piston 22 is first of all provided with a piston rod 33. This piston rod 33 is fixed to the piston 22 and reciprocates together with the piston 22 in the cylinder cavity 20. The piston rod 33 has a rectangular cross-section and moves with its distal extremity in the rectangular hole 21 in the aluminium body 6. In this way, it is well supported by one side of the rectangular hole 21.

(27) The piston rod 33 forms a toothed rack 34 which co-operates with a pinion 35 on a rotary shaft 36 which enters the cylinder cavity 20 in the first side 26 thereof. The rotary shaft 36 is provided with a seal 37. Since the rotary shaft 36 enters the cylinder cavity 20 through the top thereof and since it enters the cylinder cavity 20 in the first side 26 thereof, i.e. in the side where the hydraulic liquid is not pressurized when the closing movement is damped, no hydraulic liquid can escape through this rotating seal.

(28) Outside the cylinder cavity 20, the rotary shaft 36 is provided with a gear 38 which engages a pinion 39 which in its turn engages the toothed rack 15 on the pushrod 10. The gear 38 has a larger pitch diameter than the pinion 35 on the rotary shaft 36 so that the pinions 35 and 39 and the gear 38 form a reduction gearing between the pushrod 10 and the piston 22. In this way the piston 22 reciprocates over a smaller distance than the pushrod 10. In an alternative embodiment, the gear 38 could engage the rack 15 on the pushrod 10 directly so that the gear 38 forms the pinion engaging the rack 15 on the pushrod 10. The use of an intermediate pinion 39 enables however to arrange the pushrod 10 in the middle of the closing device so that it can be used for a left and a right turning closure member 1 without any effect on the functioning of the closing device. Optionally, a gearing comprising one or more additional pinions can be provided between the pinion 39 and the gear 38.

(29) The pinion 39 and the toothed rack 15 on the pushrod 10 forms a first motion converting mechanism converting the translational movement of the pushrod 10 into a rotational motion of the first pinion 39. This first motion converting mechanism is arranged outside the cylinder cavity 20. The second pinion 35 and the rack 34 on the piston rod 33 forms a second motion converting mechanism which is part of a transmission which transmits and converts the rotational motion of the first pinion 39 into a translational motion of the piston 22.

(30) Especially when the closing device is for outdoor use, it preferably comprises a system which provides for a compensation of the effect of a variation of the viscosity of the hydraulic liquid, as a result of a change of the temperature, on the damping effect of the hydraulic damping mechanism. Such a temperature compensation effect can be achieved by making the cylinder barrel 42 of at least one first material and the piston 22 of at least one second material which is selected to have such a thermal expansion coefficient, different from the thermal expansion coefficient of said first material, that the surface area of the clearance 43 between the piston 22 and the wall of the cylinder cavity 20 decreases when the temperature of the damper increases from 20° C. to 30° C. and increases when the temperature of the damper decreases from 20° C. to 10° C.

(31) In the embodiment described hereabove, the cylinder barrel 42 is made of extruded aluminium whilst the piston is made of a synthetic material. The piston 22 can be made, by injection-moulding, of polyoxymethylene (POM) which is sold for example under the brand Hostaform® C9021. Since the thermal expansion coefficient can depend on the geometry of the parts and on the composition thereof in case it is made of different materials, the real thermal expansion coefficient is preferably measured after having manufactured the cylinder and the piston, more particularly by measuring the diameters thereof for example at −25° C. and at 20° C. These measurements gave a thermal expansion coefficient for the cylinder of 3.23×10.sup.−5 K.sup.−1 and for the piston of 6.215×10.sup.−5 K.sup.−1.

(32) The difference between the inner diameter of the cylinder and the outer diameter of the piston 22 comprises for example 0.04 mm at 20° C. Although the cylinder cavity can be cut quite accurately in the aluminium body, this will always be with some tolerances in practice. The difference in diameter of 0.04 mm is therefore the nominal difference whilst the actual difference can vary for example between a minimum of 0.02 mm and a maximum of 0.08 mm. Depending on the tolerances of the cutting process, the nominal difference between the two diameters should therefore be large enough, in particular larger than 0.02 mm, preferably larger than 0.03 mm at 20° C. On the other hand, the difference between the two diameters should preferably not be too large so that the variation of this difference upon a change of the temperature is sufficiently large compared to the actual difference between the two diameters. The nominal difference between the two diameters, at 20° C., is therefore preferably smaller than 0.1 mm, more preferably smaller than 0.8 mm and most preferably smaller than 0.6 mm.

(33) The larger the diameter of the piston, the larger the effect of the temperature on the width of the clearance 43 between the piston 22 and the wall of the cylinder cavity 20. The diameter of the piston 22 is therefore preferably larger than 20 mm, more preferably larger than 25 mm and most preferably larger than 30 mm. The diameter of the piston is for example equal to 38 mm. In order to remain compact, this diameter is preferably smaller than 70 mm, more preferably smaller than 60 mm and more preferably smaller than 50 mm.

(34) Depending on the diameter of the piston 22, the amount of hydraulic liquid that is displaced when the piston 22 is moved from one of its two extreme positions to the other one is preferably within predetermined limits. In particular, when the diameter of the piston comprises D mm, the amount of hydraulic which is displaced when the piston moves over its maximum stroke is preferably comprised between 1.0×D ml and 3.0×D ml. This amount is more preferably larger than 1.5×D ml and preferably smaller than 2.5×D ml.

(35) For a given diameter D of the piston, the amount of liquid displaced by the piston is determined by the maximum stroke of the piston. This maximum stroke is reduced by the reduction gearing between the pushrod 10 and the piston 22. The gear ratio of this reduction gearing is therefore preferably selected so that the amount of hydraulic liquid displaced is within the above described ranges. This gear ratio is in particular preferably selected so that the distance over which the piston 22 reciprocates is at least 1.5, preferably at least 1.9 and more preferably at least 2.2 times smaller than the distance over which the pushrod 10 reciprocates.

(36) When a smaller amount of liquid is displaced upon one maximum stroke of the piston 22, the restricted fluid passages can be made smaller so that a more effective compensation of temperature variations can be obtained. The amount of liquid which is displaced is however preferably larger than a minimum amount. In this way, the stroke of the piston can be also be larger, which is advantageous especially in case a further restricted fluid passage 31 should be provided to be able to control the final closing speed, and also the clearance 43 between the piston and the wall of the cylinder cavity may be larger which enables to produce the cylinder cavity, for example by cutting, with larger tolerances.

EXAMPLE

Dimensions

(37) The closing device illustrated in the drawings has for example the following specific dimensions:

(38) TABLE-US-00001 Maximum stroke of pushrod 10: 160 mm Pitch diameter of first pinion 39: 30 mm Pitch diameter of gear 38: 57 mm Pitch diameter of second pinion 35: 24 mm Gear ratio: 0.42 (=24 mm/57 mm) Maximum stroke of piston 22: 67 mm (=160 mm × 0.42) Diameter of piston 22: 38 mm Liquid displace upon maximum stroke: 76 ml Width of clearance 43 around piston 22 at 0.04 mm 20° C.:

(39) Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the invention as set forth in the claims. Accordingly, the description and drawings are to be regarded in an illustrative sense rather than a restrictive sense.