EP2263497A1 - Method for operating a mobile piece of furniture - Google Patents

Abstract

The electric drive system opens and closes a drawer (2) in a piece of furniture (1). It incorporates an electric motor with a reduction gear (3) and a toothed belt (10) and pinion (9) drive. The electric motor is connected to an electronic control circuit which gradually increases the motor current to a maximum value for starting movement of the drawer. It holds a constant value for constant speed of movement and reverses the current for braking at the end of the drawer travel. A sensor may detect a rise in motor current due to slowing of the drawer on hitting an obstruction.

Description

The present invention relates to a method for driving a movable furniture part, in particular drawer, by a, in particular electric, drive unit.

In the case of movable furniture parts, the risk of injury to the user or the risk of damaging the movable furniture part, which already exists in the case of non-driven movable furniture parts, increases considerably through collision with an object located in the opening path of the movable furniture part. Therefore, attempts have been made in the prior art to mitigate this risk by a variety of security measures, all of which have the disadvantage of increasing the design effort and the cost of the furniture.

The object of the invention is to provide a method for driving a movable furniture part, in which these disadvantages are avoided.

This is achieved according to the invention in that the force exerted by the drive unit on the movable furniture part is regulated to a predetermined value over at least a part of the distance traveled by the movable furniture part. As a result, a deviation of the force from the predetermined value caused by a collision of the movable furniture part with an object can be detected immediately on the one hand and the force is not increased in the event of a collision, unlike the prior art, since it is based on the predetermined Value is adjusted.

Driven movable furniture parts have the further disadvantage in the prior art that the speed of the movable furniture part by the user - if at all - can be determined only limited. Even if a selection can be made from a number of predetermined target speeds, this is done in a highly unintuitive manner by actuating switching elements.

Preferably, therefore, the predetermined value of the force is chosen so that at this value just the movement of the movable furniture part inhibiting forces, such as For example, friction, be compensated and thereby a constant speed of the movable furniture part is effected. The movable furniture part therefore seems to be stored without friction.

This is preferably done after overcoming the inertia of the movable furniture part, so after the movable furniture part has been accelerated from rest to a predetermined speed. For example, the drive unit can be speed-controlled on this section of the total distance traveled by the movable furniture part. This may be, for example, one of the closed and / or the open end position of the movable furniture part upstream partial section. In this case, therefore, the acceleration and / or deceleration of the movable furniture part in the vicinity of the end positions would be speed-controlled.

For safety reasons, the speed of the movable furniture part reached after the initial acceleration phase has been completed should be so low that at this speed the damage resulting from a collision is minimal or zero.

The achieved after completion of the initial acceleration phase speed of the movable furniture part is thus maintained as long as no external intervention by a user or a collision occurs. For the user, the impression of a non-driven movable furniture part is awakened, although the drive unit is still active.

This electronic disengagement of the drive unit achieves both a simple operability of the movable furniture part and an improvement in safety:

Since the force exerted by the drive unit on the movable furniture part just compensates for the forces inhibiting the movement of the movable furniture part, the user can determine the desired speed by applying manual force (for example tension or pressure) to the movable furniture part. He is not bound to a given choice, but can choose any speed. It can of course be provided, a maximum selectable To specify speed, ie to cover the selection of possible speeds for safety reasons.

Since the speed of the movable furniture part is freely selectable by the user, there is no danger for him to be injured by a too fast movable furniture part.

It can also be provided that the force exerted by the drive unit is less than the restraining forces - preferably zero Newton (N) -, the movable furniture part thus comes to a determined by the difference between the driving force and inhibiting forces and its mass route to a standstill , To accelerate the movable furniture part then the user must be manually engaged.

Of course, it could also be provided that there is no initial acceleration of the movable furniture part, the user must therefore move the movable furniture part manually on the entire distance to be traveled by the movable furniture part.

The embodiments have in common that for the user after a possible initial acceleration phase no further drive of the movable furniture part seems to take place, although the drive unit is active. The drive unit is thus disengaged electronically, but is structurally constantly connected to the movable furniture part, whereby this in case of need, that is, in collision, can be braked immediately.

Even if there is a collision of the movable furniture part with an object, electronic disengagement of the drive unit according to the invention compared to a simple shutdown of the drive unit after the initial acceleration phase is advantageous because the drive unit immediately, that is, without the in the prior art by turning on the Drive unit conditional time delay, is available to respond to a detected collision.

In a particularly preferred embodiment of the invention it is provided that the regulation of the force to the predetermined value by regulating the Drive unit supplied current takes place, wherein the current is determined by controlling the voltage applied to the drive unit terminal voltage. In this embodiment, the collision detection could be realized as follows:

The momentary increase in the current caused by the collision is detected by the control circuit, which then regulates the current intensity. This is done by lowering the terminal voltage. If the terminal voltage falls below a predetermined or specifiable value, this is detected as a collision. Now suitable measures, such as the braking of the movable furniture part can be made.

The collision detection can be done for example by monitoring the speed of the movable furniture part or the measurement of the drive unit supplied current or the electrical voltage. For example, an increase in the current supplied to the drive unit could be detected, which is due to the forces which occur between the movable furniture part and the collision object, which the drive unit seeks to overcome. It could also be monitored a drop in the terminal voltage of the drive unit, which is due to the fact that the speed of the movable furniture part and thus the voltage in collision drops suddenly.

It could also be monitored whether the movable furniture part reached predetermined positions along the opening path within a predetermined time, although this method has the disadvantage of a very long reaction time. In any case, after collision of the movable furniture part with an object immediately appropriate measures, such as bringing to a standstill of the movable furniture part or a slight retraction of the movable furniture part, initiated.

In the case of movable furniture parts with varying masses, such as, for example, drawers with a varying degree of filling, the force to be exerted by the drive unit to overcome the forces inhibiting the movement of the movable furniture part can be determined by moving the movable furniture part over a short distance, for Example 15 millimeters, moving at a constant speed and the required force is determined.

If it is provided that the regulation of the force to the predetermined value takes place by controlling the current supplied to the drive unit, the current being determined by regulating the terminal voltage applied to the drive unit, the determination of the current required for a constant speed can also be such that the movable furniture part speed-controlled to this speed is accelerated and when reaching the speed of the present at this time current is measured. During the subsequent section, on which the movable furniture part is driven with a force regulated to a predetermined value, the thus determined current intensity of the drive unit, for example, by specifying a suitable terminal voltage, the drive unit supplied.

It can also be provided that the predetermined value of the force exerted by the drive unit causes an acceleration of the movable furniture part. This would be particularly advantageous for long to be covered by the movable furniture part ways to shorten the time required for this. If the resulting acceleration is not too great, the impression of a non-driven piece of furniture is still almost created. In any case, the advantageous safety aspects are fully preserved.

For structural simplification it can be provided that the determination of the force takes place directly in the drive unit. This may be, for example, a measurement of the current supplied to the drive unit, which is directly proportional to the torque exerted by the drive unit. This is in a known manner with the force exerted on the movable furniture part in connection.

If the force exerted by the drive unit on the movable furniture part, for example via a gear that drives a roller with radius r, the role of a guided over them rope or timing belt drives the movable furniture part, the torque M results from the formula

M = Γ.CI,

where I is the current supplied to the drive unit, r is the reduction ratio of the transmission, and C is an engine constant. This results in the force exerted on the rope or the toothed belt and thus the movable furniture part from the known formula

F = M / r.

The determination of the force exerted by the drive unit on the movable furniture part force can also be done by a mechanical force sensor or by a mechanical torque sensor. If the determination of the force is provided by a current measuring device, this need not of course be arranged in the drive unit.

Fig. 1 bis 3

Ausführungsbeispiele von Möbeln, wobei das erfindungsgemäße Verfahren auf verschiedene Arten realisiert wird,

Fig. 4a-d bis 6a, 6b

die Stromstärke sowie die Geschwindigkeit des bewegbaren Möbelteils in Abhängigkeit der Zeit für verschiedene Ausführungsformen des erfindungsgemäßen Verfahrens,

Fig. 7a-d

in schematischer Darstellung die Kollision des bewegbaren Möbelteils mit einem Objekt sowie die der Antriebseinheit zugeführte Stromstärke und die Geschwindigkeit des bewegbaren Möbelteils in Abhängigkeit der Zeit und

Fig. 8a, 8b

die Geschwindigkeit des bewegbaren Möbelteils in Abhängigkeit der Zeit für einen beispielhaften Öffnungs- und Schließvorgang.

Further advantages and details of the invention will become apparent from the following description of the figures. Showing:

Fig. 1 to 3

Embodiments of furniture, wherein the inventive method is realized in various ways,

Fig. 4a-d to 6a, 6b

the current intensity and the speed of the movable furniture part as a function of time for various embodiments of the method according to the invention,

Fig. 7a-d

in a schematic representation of the collision of the movable furniture part with an object as well as the power unit supplied to the drive unit and the speed of the movable furniture part as a function of time and

Fig. 8a, 8b

the speed of the movable furniture part as a function of time for an exemplary opening and closing operation.

Fig. 1 shows in schematic form a furniture 1 with a plurality of movable furniture parts 2, wherein the uppermost movable furniture part 2 is shown extended. In the detailed representation are further a drive unit 3, which is an electric motor in this embodiment, and a roller 9 and a guided over it Timing belt 10 recognizable. The drive unit 3 drives the roller 9 and thus the toothed belt 10. By the toothed belt 10, the movable furniture part 2 is moved in a known manner. In the in Fig. 1 illustrated embodiment, the drive unit 3 includes a current measuring device, not shown for inventively provided determination of the force exerted by the drive unit 3 on the movable furniture part 2 force.

The embodiment of Fig. 2 is different from that of Fig. 1 in that the determination of the force is not effected by a current measuring device integrated in the drive unit 3, but by a mechanical force sensor 4 contacting the toothed belt 10. For ease of recognition, only the drive unit 3, the roller 9, the toothed belt 10, the frames 8 and the mechanical force sensor 4 are shown. The drive unit 3 is shown detached from this for better visibility of the roller 9.

At the in Fig. 3 illustrated embodiment, a torque sensor 5 is provided for determining the force. For ease of recognition, only the drive unit 3, the roller 9, the toothed belt 10, the frames 8 and the mechanical force sensor 4 are shown. The drive unit 3 is shown detached from these for better visibility of the roller 9 and the torque sensor 5.

The Fig. 4a and 4b now show on the basis of the drive unit 3 supplied current I or the velocity v of the movable furniture part 2, in dependence on the time since the activation of the drive unit 3 time t an embodiment of the method according to the invention for driving the movable furniture part 2:

During a first period of time t ₁ , in which the movable furniture part 2 covers the partial path S ₁ upstream of the closed end position, a speed control of the drive unit 3 for acceleration of the movable furniture part 2 takes place from standstill. During the time t ₁ , therefore, there is an increase in the current I supplied to the drive unit 2, which, as in FIG Fig. 4b shown causes an increase in the speed v of the movable furniture part 2.

After expiration of the time period t ₁ , the force exerted by the drive unit 3 on the movable furniture part 2 is now regulated to a predetermined value. This is done in this embodiment by controlling the current I to the predetermined value I ₀ during the period t ₂ , in which the movable furniture part 2 travels the leg S ₂ in the absence of a collision with the constant speed v ₀ . The current intensity I is regulated by specifying the voltage applied to the drive unit 3 terminal voltage:

After the expiration of the time period t ₂ , the movable furniture part ₂ reaches the vicinity of its open end position, which can be detected, for example, by sensors, not shown.

For the braking of the movable furniture part 2 takes place during the period t ₃ again a speed control of the drive unit 3, as in Fig. 4a shown. This leads to the in Fig. 4b illustrated speed course. After the end of the total time t ₁ + t ₂ + t ₃ , the movable furniture part 2 is in the presence of a collision in its open end position.

The Fig. 4c and 4d show the embodiment of Fig. 4a and 4b with the difference that during the periods t _A and t _B a manual intervention by a user, not shown, occurs:

During the period t _A , the user exerts pressure on the movable furniture part 2, whereby its speed v ₀ decreases to a lower value v _A. Since the drive unit 3 compensates for the forces inhibiting the movement of the movable furniture part 2, the movable furniture part 2 moves evenly at this lower speed v _A.

During the period t _B , the user exerts traction on the movable furniture part 2, which increases its speed v _A to a higher value v _B. Since the drive unit 3 compensates for the forces inhibiting the movement of the movable furniture part 2, the movable furniture part 2 moves evenly at this higher speed v _B.

The Fig. 5a and 5b show a further embodiment of the method according to the invention, which differs from that in the Fig. 4a and 4b illustrated embodiment characterized in that a larger offset I ₀ (that is, a different from 0 current I) is selected. As a result, the movable furniture part 2 undergoes an acceleration during the time span t ₂ in which it covers the section S ₂ .

That in the Fig. 6a and 6b illustrated embodiment of the invention differs from the preceding embodiments in that after the first time period t _1, the current I is controlled to the value 0, so that the force exerted by the drive unit 3 on the movable furniture part 2 force to the value 0 N is regulated , The drive unit 3 remains active. As in Fig. 6b illustrated, the movable furniture part 2 runs during the period t ₂ under the influence of frictional forces and remains in a position between closed and open position.

In the Fig. 7a to 7d an embodiment of the method according to the invention for the case of a collision of the movable furniture part 2 is shown with an object 7:

As Fig. 7c shows the current I was after the time t ₁ , in which a speed control was carried out, regulated to the value l ₀ , in which the movable furniture part 2 a constant speed v ₀ ( Fig. 7d ). At time t _{C it} comes to the in Fig. 7a or 7b illustrated collision of the movable furniture part 2 with the schematically shown object 7, which, as in Fig. 7c represented causes a momentary increase in the current I from the value l ₀ . The amount and duration of the increase were greatly exaggerated. The current intensity I is then back-regulated by lowering the voltage applied to the drive unit 3 terminal voltage. In this case, the terminal voltage falls below a predetermined value, which is detected as a collision. In response, the deceleration of the movable furniture part 2 is immediately caused by the drive unit 3, so that the damage resulting from the collision is minimized. This is done by a known reversal of the polarity of the terminal voltage.

Fig. 8a shows an example of an opening process.

In the time between t ₀ and t _{1 there} is a speed-controlled acceleration. At the time t ₀ , the amount v _{0 of} the speed of the movable furniture part 2 caused by the pulling of the user is measured. In this exemplary embodiment, a value of a ₀ = 1.5 m / s ^{2 is} provided for the acceleration a ₀ . The movable furniture part 2 is accelerated until the amount v _{1 of} the minimum speed (here: v ₁ = 0.12 m / s) at time t _{1 is} reached.

When the minimum speed has been reached, the motor current is measured and switched to the control of the current (corresponds to the torque M). The measured value of the current I serves as the setpoint I ₀ for the current control.

Should the friction change during this movement sequence (for example due to load-dependent depressions or path-dependent control and locking units of the guide system of the movable furniture part 2), the movable furniture part 2 is accelerated or decelerated with a constant engine torque M.

So that the movable furniture part 2 does not become too fast or slow due to the change in the friction, both a minimum speed value v _{12, min} and a maximum speed value v _{12, max are} monitored (here: v _{12, min} = 0.2 m / s , v _{12, max} = 0.25 m / s). If the limits are exceeded or fallen short of, the setpoint I _{0 of} the motor current I is incrementally reduced (for example by ΔI = 15.6 mA every 2 ms) or increased until a speed between the limit values is reached.

The current increment ΔI is ΔI = 15.6 mA. This corresponds to a force differential ΔF of AF = 0.4 N. The maximum value of the current intensity I _{12, max} and the associated force F _{12, max} are I _{12, max} = 530 mA and F _{12, max} = 14 N. The minimum values are I _{12, min} = 340 mA and F _{12, min} = 9 N.

If the movable furniture part _{2 reaches} a predetermined distance Δs from the end stop at time t ₂ , the speed v _{2 is} measured and the necessary deceleration a _{2 is} determined via a ₂ = v ² ₂ / Δ (s · 2), so that the movable furniture part 2 is secure comes to a stop before the end position. For example, Δs = 130 mm. After Calculation of a ₂ is switched from the control of the current I to the control of the speed (setpoint of the speed, is reduced according to the delay).

If the minimum opening speed v _{3 is} reached at t ₃ , the movable furniture part 2 is moved with this speed (here: v ₃ = 0.065 m / s) to the end stop.

Fig. 8b shows a to in Fig. 8a opening operation shown analog closing. For safety reasons, the speeds were slightly lower and the braking distances slightly larger.

At time t ₀ , the velocity v _{0 is} measured. The acceleration a ₀ is a ₀ = 1.4 m / s ² . The velocity v ₁ is v ₁ = 0.68 m / s.

At time t ₁ , for the minimum value of speed v _{12, min} = 0.12 m / s and for the maximum value of speed v _{12, max} = 0.125 m / s were selected.

The current increment ΔI is ΔI = 15.6 mA. This corresponds to a force differential .DELTA.F of .DELTA.F = 0.4 N. The maximum allowable current intensity I _{12, max} and the corresponding maximum force F _{12, max} on the movable furniture part 2 amount to I _{12, max} = 690 mA and F _{12, max} = 18 N. The minimum values are I _{12, min} = 330 mA and F ₁₂ = 9 N.

At time t ₂ (Δs = 160 mm) the velocity v _{2 is} measured and from this the delay a _{2 is} calculated.

From the time t ₃ , the speed v ₃ = 0.065 m / s until the time t _4, the end stop is reached.

Claims (11)

Method for driving a movable furniture part, in particular a drawer, by a, in particular electric, drive unit, characterized in that at least over a partial section (S ₂ ) of the path to be traveled by the movable furniture part (2) from the drive unit (3) the movable furniture part (2) exerted force is regulated to a predetermined value. A method according to claim 1, characterized in that the predetermined value is zero Newton (N). A method according to claim 1, characterized in that the predetermined value causes a constant speed of the movable furniture part (2). A method according to claim 1, characterized in that the predetermined value causes an acceleration of the movable furniture part (2). Method according to one of claims 1 to 4, characterized in that the movable furniture part (2) at least on a partial section (S ₁ , S ₃ ) of the movable furniture part (2) zurückzulegenden way (S) is driven speed controlled. A method according to claim 5, characterized in that the movable furniture part (2) is movable between a closed and an open end position and on one of the closed end position upstream part of the route (S ₁ ) and / or on one of the open end position upstream sub-section (S ₃ ) of the movable furniture part (2) zurückzulegenden way (S) is driven speed controlled. Method according to one of claims 1 to 6, characterized in that it is determined at which value of the force exerted by the drive unit (3) on the movable furniture part (2), the speed of the movable furniture part (2) is constant. Method according to one of claims 1 to 7, characterized in that the determination of the force takes place directly in the drive unit (3). Method according to one of claims 1 to 8, characterized in that the force is determined by a mechanical force sensor (4). Method according to one of claims 1 to 8, characterized in that the force is determined by a mechanical torque sensor (5). Method according to one of claims 1 to 8, characterized in that the force is determined by a current measuring device (6).

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