WO2013017478A1

WO2013017478A1 - Self-closing system for a movable furniture part

Info

Publication number: WO2013017478A1
Application number: PCT/EP2012/064505
Authority: WO
Inventors: Andreas Hoffmann; Bastian Stein
Original assignee: Druck- und Spritzgußwerk Hettich GmbH & Co. KG
Priority date: 2011-08-01
Filing date: 2012-07-24
Publication date: 2013-02-07
Also published as: DE102011052329A1

Abstract

A self-closing system for a movable furniture part, more particularly for a drawer system, the furniture part having a cushioning device for cushioning a closing movement, the cushioning device having a dilatant cushioning fluid and the cushioning device having a self-regulating cushioning depending on the load on the movable furniture part over a pre-determined cushioning travel.

Description

Self-closing system for a movable furniture part

The invention relates to a self-closing system for a movable furniture part according to the preamble of claim 1. There are known damping devices which are controllable by valve technology or control circuits. In such systems, for example, magneto-viscous damping media or multi-stage valves are used. However, these control loops require additional design effort and are partly due to the necessary electrification not be used in furniture.

DE 10 2004 058 736 A1 and DE 1 1 2006 002 023 T5 disclose fluid dampers which operate with the aid of a magnetorheological fluid. In this case, under the influence of a magnetic field, a change in viscosity occurs. WO 2010/022424 A1 discloses a furniture fitting with a damping device, in which a plurality of different sized solids is arranged. By the use of the solid state mixture on the one hand leakage of a liquid or viscous damping medium to be avoided. On the other hand, damping should be achieved by the interacting friction of the solid particles. A loss of viscosity due to the shear of long-chain polymers in a limited space should be avoided.

When using conventional damping systems, for example linear dampers, in a piece of furniture, they only work optimally in a specific load range. This has the consequence that a respective Selbsteinzugssystem for a movable furniture part, for example in drawer systems for a certain load range works optimally.

The present invention sets in the task of creating a self-closing system with a damping device, which has a uniform feed even with different loads on a movable furniture part, in particular a drawer.

This object is achieved by a self-retraction system having the features of claim 1. According to the invention, a self-closing system for a movable furniture part, in particular for a drawer system, a damping device for damping a retraction movement, wherein the damping device comprises a dilatant damping fluid and the damping device is a self-regulating

Has damping in response to the load of the movable furniture part over a predetermined damping path.

The use of a dilatation damping fluid means that no or only minor structural adjustments are required in existing systems. In the case of normal load, for example in drawers in the unloaded state, a damping takes place as in the use of a conventional damping oil. If a higher load is applied, the effect of the dilatancy or the shear strain of the damping fluid is utilized by the increased shear rate. Due to the thickening of the dilatant

Damping fluid is achieved a higher damping effect. However, once the system has been slowed down to a lower speed, the effect is canceled out. As a result, a uniform motion picture is achieved. Impact noises are reduced independently of the drawer load and allow self-closing over the entire damping path.

Advantageous embodiments of the invention are the subject of the dependent claims.

A dilatancy in a damping fluid can advantageously be made possible by the damping fluid being a liquid or a viscous mass which has suspended nanoscale solid particles. Due to their small size, the nanoscale solid particles do not hinder the functioning of the damping device, for example the movement of a piston in a cylinder. By selecting the size of the suspended solid particles, it is possible to achieve a suspension with a high solids volume content. This has an influence on the dilatant properties of the damping fluid.

The damping device allows the damping of the retraction speed of a drawer to a stop, the load on the length of the damping path has no influence. The length of the damping path, however, depends on the dilatant properties of the damping fluid. To the Damping to adapt to the particular damping fluid used and thus to allow movement to a stop, it is advantageous if the damping path is adjustable by mechanical adjusting means on the damping device.

It is also advantageous if the damping fluid has a kinematic initial viscosity, which is determined by the damping travel of an unloaded drawer. The dilatancy of the fluid damping agent is adjustable, for example, by the concentration of the nanoscale solid particles in the liquid or the viscous mass. In this case, the concentration of the nanoscale solid particles can be selected such that the kinematic viscosity of the damping fluid increases during the movement of the drawer by at least 100%, preferably by at least 200-400%. As a result, damping of drawers with particularly high loads without stop noises is advantageously achieved.

Moreover, it is advantageous if the liquid or the viscous mass comprises an oil, particularly preferably a silicone oil. This allows lubrication of the damping device.

Although it is also conceivable that the damping device damps a rotational movement, in which case the damping travel can be determined on the basis of the angular amount. However, it is particularly advantageous if the dampening device damps a linear retraction movement, since the dilatant properties of the damping fluid can be better utilized due to the linear movement. It is advantageous if the suspended nanoscale solid particles have an average particle size between 10-350 nm, particularly preferably 15-100 nm. Smaller or larger nanoparticles have less influence on the dilatancy of the damping fluid. An advantageous variant of the invention and the resulting advantages for a Selbsteinzugssystem, as well as several generic Ausführungsvarian- th from the prior art will be explained in more detail with reference to the drawings. They show:

Figure 1 is a diagram for describing the damping behavior of a Selbsteinzugssystems invention;

FIG. 2 shows a diagram for describing the change in the kinematic viscosity of a dilatant damping fluid in the self-retraction system according to the invention of FIG. 1;

3 shows a diagram for describing the damping behavior of a

Self-closing system with a generic damping device with constant kinematic viscosity of 450 CentiStokes;

4 shows a diagram for describing the damping behavior of a

Selbsteinzugssystems with a generic damping device with a constant kinematic viscosity of 300 CentiStokes; and

Figure 5: a diagram for describing the damping behavior of a

Selbsteinzugssystems with a generic damping device with a constant kinematic viscosity of 150 CentiStokes.

There are a variety of damping devices are known in which a damping fluid is used. The amount of damping, ie how much a movement is slowed down within a set period of time depends i.a. from the viscosity of the damping fluid. Corresponding damping devices of linear movements can be obtained for example by a piston-cylinder arrangement, wherein the movement of the piston is braked by displacement of the damping fluid in the cylinder.

A corresponding damping device can be used, for example, as a separate damping device, preferably as a linear damping device, or in a fitting, for example a fitting for a sliding door or a hinge. Preferably, such a damping device can also be used in furniture or household appliances. A self-closing system can be used for all movable furniture parts. Particularly preferably, the damping device can be used in a self-closing system of a drawer system, whereby the damping of the intake speed is made possible. Figure 1 describes the course of movement when performing a closing operation on a drawer, which has a damping device according to the invention and is transferred from an open to a closed state. The drawer is set in motion and impinges on the damping device at a speed v ₀ as a function of the load at the position A. In this case, the damping device is designed such that it ensures movement of the drawer to the system stop even with unfilled drawers.

To illustrate the course of the movement, the speed was plotted over the attenuation path (in mm). For example, the maximum speed can be assumed to be v _max = 1 m / s.

As can be seen from FIG. 1, first of all a linear or at least approximately linear attenuation takes place within a first attenuation distance xi or delay distance xi. This area reflects the normal movement of a drawer before the action of the damping device. This linear damping is due to frictional resistance in the leadership of the drawer. A linear damping means a constant drop of the speed by an amount M as the damping path progresses in the region of the first damping path xi. The amount M depends on the load with which the respective drawer is loaded. In Figure 1, the damping behavior was tested on a drawer, which each had a load of 10, 20 and 30 kg. The amount M is greater, the greater the load which acts on the drawer.

In FIG. 2, the change in the kinematic viscosity v in [m ² / s] of a damping fluid in the damping device at a constant temperature of 25 ° C. as the damping path for the course of motion of FIG.

1 illustrated drawers with a load of 10, 20 and 30 kg shown. there is kinematic initial viscosity v _{0 of} the damping fluid 150

Centistokes.

As the movement progresses, the first attenuation path xi transitions into the second attenuation path X2. Within the second damping section, the action of the damping device results in non-linear damping of the drawer. In the process, a resistance gradually builds up within the damping device, which counteracts the movement of the drawer. This resistance is dependent on the kinematic viscosity of the damping fluid. The non-linear damping causes an abrupt non-linear reduction in the speed of the drawer.

The increase in resistance, which counteracts the movement of the drawer and leads to an increase in the non-linear damping, based on the dilatancy or the shear toughness of the damping fluid used in the damping device.

As can be seen from FIG. 2, the kinematic viscosity increases abruptly by about 550 centiStokes along the second attenuation distance X2 and then decreases linearly, preferably by 20 cSt / mm.

As the movement progresses further, as shown in FIG. 1, the speed characteristics of the drawer with different load are approaching, so that the drawer, despite different loading along a third damping distance X3 to an entry stop B, has approximately the same speed drop.

As is apparent from Figure 2, the kinematic viscosity approaches

Damping fluids during the movement of the drawer along the third attenuation distance X3 to the initial value of 150 CentiStokes again.

As can be seen from FIG. 1, the use of the dilatant damping fluid of the drawer stops the system stop B, independently of the respective load of the drawer, since the decrease curves of the retraction speeds along the third damping section X3 for the different drawer systems equalize one another. In this case, the actual damping path x in FIGS. 1 and 2 is composed of the damping sections x ₂ and X ₃ .

As can be seen from the synopsis of FIGS. 1 and 2, a higher load of the drawer at the same speed in the damper produces a higher shearing force and this causes an increase in the kinematic viscosity. This is accompanied by an increase in the braking function of the damper. However, as soon as the shear force returns due to the stronger braking effect, the kinematic viscosity of the damping medium also changes in direct dependence. By this self-regulating damping as a function of the load of the drawer can be achieved in practice, a uniform motion picture for a drawer movement regardless of the load of the drawer. FIGS. 3-5 describe movement profiles of a drawer with different payloads under analogous conditions and with the same damping travel, but with the use of a conventional damping oil without dilatant properties, as known from the prior art. FIG. 3 describes courses of movement of a drawer with different ones

Payloads on a damper filled with a damping oil having an initial kinematic viscosity of 450 centiStokes. In this case, there is a relatively abrupt damping, so that the drawer comes to a standstill with less load already before passing through the entire damping path x. This has the consequence that this drawer is not applied to the system stop B and manually must be moved to the system stop B. Self-closing can thus be guaranteed only for certain payloads.

FIG. 4 describes the course of movement of a drawer onto a damping device which is filled with a damping oil having a kinematic initial viscosity of 300 centiStokes. In this case, there is a relatively balanced damping, although the drawer comes with a load of only 10 kg also before passing through the entire damping path to a standstill. Self-closing can therefore only be ensured for certain payloads in these cases. Drawers with a higher load of 30 kg are slowed down in their feed movement only by the system stop. However, drawers can move in the opposite direction again by the collision with the retraction stop, unless holding means such as magnets or the like are provided separately. However, such additional closure systems can be dispensed with when using the damping device according to the invention.

Also in Figure 5 takes place when pulling the drawers with a load of 10 or 20 kg an undesirable collision with the system stop B? with an equally undesirable impact noise. Here, Figure 5 describes the course of movement of the drawers on a damping device which is filled with a damping oil having a kinematic initial viscosity of 150 CentiStokes.

The dilatancy of the damping fluid can be made possible by the addition of nanoscale solid particles to a viscous or liquid medium, so that a suspension with scherverdickenden properties (so-called shear-thickening properties) is formed.

In this case, the liquid medium may be a lubricant, preferably an oil, for example mineral oil.

Particularly preferred is silicone oil, due to its consistent properties with prolonged use and due to its viscosity-temperature behavior.

As nanoscale solid particles inorganic or organic solid particles can be used which are insoluble in the liquid medium. The average particle diameter of the nanoscale solid particles is in the range of 1 nm-1 m, but preferably in the range of 10-350 nm.

Claims

claims

1 . Selbsteinzugssystenn for a movable furniture part, in particular for a drawer system, wherein the furniture part has a damping device for damping a retraction movement, characterized in that the damping device has a dilatant damping fluid and the damping device a self-regulating damping function of the load of the movable furniture part via a predetermined damping path having.

2. Selbsteinzugssystem according to claim 1, characterized in that the dilatant damping fluid is a liquid or a viscous mass, which has suspended nanoscale solid particles.

3. Selbsteinzugssystem according to claim 1 or 2, characterized in that the predetermined damping path is adjustable by mechanical adjusting means on the damping device.

4. Selbsteinzugssystem according to any one of the preceding claims, characterized in that the damping fluid has a kinematic initial viscosity, which is determined by the damping path of an unloaded drawer.

5. Selbsteinzugssystem according to any one of the preceding claims, characterized in that the kinematic viscosity of

Damping fluid during the movement of the drawer by at least 100%, preferably by at least 200-400%, increases.

6. Selbsteinzugssystem according to any one of the preceding claims, characterized in that the kinematic viscosity of

Attenuation fluid is adjustable by the concentration of suspended nanoscale solids.

7. Selbsteinzugssystem according to any one of the preceding claims, characterized in that the liquid or viscous composition comprises an oil, particularly preferably a silicone oil.

8. Selbsteinzugssystem according to any one of the preceding claims, characterized in that takes place by the damping device, the damping of a linear retraction movement.

9. Self-closing system according to one of the preceding claims, characterized in that the suspended nanoscale solid particles have an average particle size between 10-350 nm.

10. Selbsteinzugssystem according to any one of the preceding claims, characterized in that the damping device has a cylinder-piston arrangement.

1 1. Self-closing system according to one of the preceding claims, characterized in that the damping device is a rotary damper.