WO2003038299A2

WO2003038299A2 - Damping arrangement

Info

Publication number: WO2003038299A2
Application number: PCT/EP2002/012316
Authority: WO
Inventors: Ingemar Andersson
Original assignee: Electrolux Home Products Corporation N.V.
Priority date: 2001-11-02
Filing date: 2002-11-01
Publication date: 2003-05-08
Also published as: GB2396682B; GB2396682A; GB0410492D0; SE0103664D0; WO2003038299A3; AU2002357489A1

Abstract

An arrangement for progressively damping a turning movement comprises a housing (2, 3, 4) and a rotary plunger in the shape of a vane (11) mounted therein. The vane (11) is movable between two end positions (22, 23) within a chamber (9) filled with a viscous liquid, said vane (11) dividing said chamber (9) into two compartments (9a, 9b). The two compartments (9a, 9b) communicate via passages (8), whose area varies with the position of the vane. Said vane has at least one opening (21) offering communication between the two compartments (9a, 9b) over essentially its whole surface, said opening (21) being covered by a valve membrane (12) arranged to open in one direction of movement of the plunger and close in the other direction.

Description

Damping arrangement

The present invention refers to damping arangements, in particular for damping of the movement of a lid associated with a cooker top. Damping shall take place of the closing movement of the lid from a nearly vertical starting position into an essentially horizontal end position, in which the lid completely covers the cooker top. However, the lifting movement of the lid from the horizontal into the vertical position shall take place without any essential damping.

The patent publication EP 0997869 A2 discloses a damping arrangement in which a rotary damper has a torque control mechanism accomodated in a chamber filled with a viscous fluid. The chamber is divided into two compartments which are interconnected by a further chamber defined by a partition wall provided with first and second communication holes. A check valve prevents the viscous fluid from flowing in the first communication hole from the further chamber toward the first compartment.

The patent publication FR 1227061 discloses a hydraulic j ack comprising a chamber filled with a viscous fluid and further containing a rotary plunger. The chamber has a shape similar to that of a sector of a circle and the shaft of the rotary plunger is disposed so as to have its axis of rotation disposed in the centre of the circle.

Finally, the patent publication DE 195677 discloses an arrangement for damping of oscillations of supporting springs in vehicles. The arrangement comprises a chamber filled with a viscous fluid and further containing a rotary plunger. The plunger has the shape of a vane provided with through holes coperating with one or more valve membranes for the control of the degree of damping with respect to the force acting on the vehicle spring.

With reference to EP 0997869 A2, referred to above, the shaft of the rotary plunger is positioned in the center of a circular chamber and, moreover, the channel opened by the check valve is formed and disposed so as to cause a damping effect also during movement of the plunger in a direction where no damping effect should occur.

The object of the invention is to provide a rotary damper in which when the rotary plunger is moved in a direction opposite to that in which damping takes place the movement is essentially free of any damping forces. The object is achieved in a rotary damper which has obtained the characterizing features indicated in the appending claim 1. Preferred embodiments have been included in the accompanying sub-claims.

The invention will now be described more in detail in connection with an embodiment with reference to the accompanying drawings in which:

Fig. 1 shows, in a perspective view, a rotary damper according to the invention; Fig. 2 shows the rotary damper according to Fig. 1 with two outer end plates removed; Fig. 3 shows the rotary damper of Fig. 2 with two inner end plates removed; Fig. 4 shows the rotary damper of Fig 3 with the damper housing removed, and Fig. 5 shows a detail view of a rotary plunger included in the rotary damper.

Fig. 1 shows an embodiment of a damping arrangement according to the invention intended to be used in connection with a cooker. The arrangement comprises two outer end plates 2, two inner end plates 3 and an intermediate member 4 all together forming a closed chamber 9. In the outer end plates 2 holes have been formed for a shaft 1 to be turnably journalled. In the inner and outer end plates 3, 2 as well as in the intermediate member 4 holes 6 have been provided by means of which the arrangement can be secured to the cooker, for example by the use of screw and nut joints. At one end of the shaft 1 a lateral arm 7 has been fixed and holes have been formed in the arm for joining the same to a lid intended to cover the top of the cooker when moved to a horizontal position. All end plates 2, 3 have an outer shape which is adapted to the shape of the intermediate member 4 in order to cover the intermediate member and to form a closed chamber 9 which is to be filled with a viscous fluid such as silicone oil or the like. When the arrangement has been assembled the arm 7 can move freely between two end positions disposed about 90 ° apart.

With reference to Fig. 2 the rotary damper is shown with the outer end plates 2 removed. The inner end plates 3 are provided with through holes 8 of curved wedge-shape. The inner end plates 3 are made from a material which is heat resistant, has proper chemical properties and which can serve as a gasket between the intermediate member 4 and the outer end plates 2 preventing viscous fluid from escaping from the chamber 9. The through holes 8 form passages through which fluid can flow between two compartments 9a, 9b formed in the chamber by a rotary plunger 11, see Fig. 3, acting as a movable partition wall defining the two compartments 9a, 9b. The passages (through holes 8) are formed upon mounting of the outer end plates 2. The rotary plunger 11 is fixedly secured to the shaft 1 which is provided with shoulders 16 which together with corresponding shoulders 5, provided on the outer end plates 2, fixes the shaft 1 axially.

With reference to Fig. 3 the inner end plates 3 have been removed giving access to the interior of the chamber 9 in which the rotary plunger 11 is mounted to be turned between end positions determined by corresponding walls 22, 23 in the chamber 9. As seen in Fig. 4 and 5, the rotary plunger has the shape of a vane 11a made integral with a sleeve 1 lb which is pressed on the shaft 1 to move therewith. The vane 1 la is provided with two through openings 21 which together cover almost the whole the the surface of the vane 1 la. A valve membrane 12, preferably in the foπn of a thin steel blade, is mounted on the vane 1 la to cover the two through openings 21. At one side the valve membrane 12 is clamped between the vane 11a and a clamping member 10 also serving as a distance member cooperating with the wall 23 to define one end position for the rotary plunger 11 in the chamber 9. Guide pins 14 and a screw 15 cooperate with corresponding holes 19, 20 (Fig. 5) to fix the clamping member 10 and the valve member 12 in the positions shown in Fig. 4. The vane 1 la has a shape so as to completely fill the space between the two inner end plates 3 permitting fluid flow between the two compartments 9a, 9b only via the holes 8 or, alternatively, via the holes 21 depending on the direction of movement of the rotary plunger 11.

The damping arrangement described above operates in the following way.

In the embodiment described the damping arrangement is mounted on a cooker with the arm 7 secured to a lid covering the top of the cooker when not in use. In this position the lid extends essentially horizontally and from this position the lid is turned upwards into an essentially vertical position permitting the various heating areas on the cooker top to be used. During the movement of the lid into its vertical position essentially no damping should take place and, to that end, when the rotary plunger 11 is moved towards its end position 22 in the chamber 9 the valve membrane 12 opens and the viscous fluid present in the chamber 9 can flow almost freely through the openings 21 in the vane 11a. When cooking operations have been concluded the lid is again to be moved to its horizontal position and during this movement of the lid the damping arrangement will be activated. When the rotary plunger 11 is moved in the opposite direction from its end position 22 towards its end position 23 the valve membrane 12 is pressed by the viscous fluid towards the vane 11a closing the through openings 21 and forcing the viscous flow to flow from one side of the vane 1 la to the opposite side thereof via the openings 8 the through area of which diminishes progressively during the course of movement. Acordingly, the damping force is increasing correspondingly which means that the vane 11a will softly approach its end position 23 in the chamber 9.

Claims

C l a i m s

1. Arrangement for damping of a turning movement, comprising a housing (2, 3, 4), a shaft (1) turnably mounted in the housing (2, 3, 4) and having an arm (7) secured to one end thereof, said housing (2, 3, 4) being fixed to an apparatus, a machine or the like whereas said arm (7) is secured to a movable part associated with the apparatus, the machine or the like, the housing (2, 3, 4) comprising a chamber (9) filled with a viscous fluid and a rotary plunger (11) being fixed to the shaft (1) to move therewith inside the chamber (9) between first and second end positions(22, 23), said rotary plunger (11) dividing the chamber (9) into two compartments (9a, 9b) interconnected by a passage (8) controlling the fluid flow between the two compartments during movement of the plunger (11) in the direction from the first end position (22) to the second one (23), characterized in that the chamber (9) has a shape mainly conforming to a sector of a circle with the axis of rotation of the shaft (1) passing through the centre of the circle, that the plunger (11) has the shape of a vane (11a) having at least one opening (21) offering communication between the two compartments (22, 23) over essentially the whole of its surface, said opening (21) being covered by a valve membrane (12) arranged to open during the movement of the plunger (11) from the second end position (23) to the first one (22) and to close during movement of the plunger from the first end position (22) to the second one (23).

2. Arrangement according to claim 1, characterized in that the passage (8) controlling the fluid flow between the two compartments (9a, 9b) is adapted to progressively reduce said fluid flow during the movement of the plunger (11) from the first end position (22) to the second one (23).

3. Arrangement according to claim 1, characterized by a distance member (10) determining the second end position (23) of the plunger (11), said distance member (10) being adapted to clamp the valve membrane (12) to the plunger (11) to which it is secured by means of screws or the like.

4. The use of an arrangement according to any of the claims 1-3 in connection with a lid associated with a cooker top or the like.