EP1624772A1

EP1624772A1 - Method for driving a movable part of a piece of furniture

Info

Publication number: EP1624772A1
Application number: EP04730798A
Authority: EP
Inventors: Edgar Huber; Uwe Scheffknecht
Original assignee: Julius Blum GmbH
Current assignee: Julius Blum GmbH
Priority date: 2003-05-19
Filing date: 2004-05-03
Publication date: 2006-02-15
Anticipated expiration: 2024-05-03
Also published as: EP1624772B1; CN1787764A; AT503998A1; MY136748A; EP2263497A1; EP2263497B1; CN100482126C; JP2007502181A; WO2004100717A1; US20060261775A1; JP5036313B2; US7282884B2; AT503998B1

Abstract

Disclosed is a method for driving a movable part of a piece of furniture, especially a drawer, by means of a particularly electric drive unit. The force applied to the movable part (2) of the piece of furniture by said drive unit (3) is regulated to a predefined value, at least across a partial distance (S2) of the distance (S) that is to be covered by the movable part (2) of the piece of furniture.

Description

Method for driving a movable furniture part

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

In the case of movable furniture parts, the risk of injury to the user or the risk of damage to the movable furniture part due to collision with an object located in the opening path of the movable furniture part increases considerably, already existing in the case of non-driven movable furniture parts. Therefore, in the prior art, attempts have been made to mitigate this danger by means of a wide variety of security measures, all of which have the disadvantage of increasing the construction effort and the manufacturing costs 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 at least over a partial distance of the path to be covered by the movable furniture part. In this way, on the one hand, a deviation of the force from the specified value caused by a collision of the movable furniture part with an object can be detected immediately on the one hand, and on the other hand, unlike in the prior art, the force is not increased in the event of a collision, since it is based on the specified one Value is corrected.

In the prior art, driven movable furniture parts also have the disadvantage that the speed of the movable furniture part can be determined by the user, if at all, only to a limited extent. 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.

Therefore, the predetermined value of the force is preferably selected such that, at this value, the forces which inhibit the movement of the movable furniture part, such as friction, are compensated for, thereby causing a constant speed of the movable furniture part. The moveable part of the furniture therefore seems to be mounted without friction. This preferably takes place after the inertia of the movable furniture part has been overcome, 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 entire path to be covered by the movable furniture part. This can be, for example, a section upstream of the closed and / or the open end position of the movable furniture part. In this case, the acceleration and / or braking 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 end of the initial acceleration phase should be chosen so low that at this speed the damage occurring in the event of a collision is minimal or zero.

The speed of the movable furniture part reached after the end of the initial acceleration phase is thus maintained as long as no external intervention by a user or a collision takes place. For the user, this gives the impression of a non-driven, movable furniture part, although the drive unit is still active.

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

Since the force exerted by the drive unit on the movable furniture part compensates precisely the forces which inhibit the movement of the movable furniture part, the user can determine the desired speed by manually exerting force (for example pulling or pushing) on the movable furniture part. He is not bound to a given selection, but can choose any speed. It can of course be provided to specify a maximum selectable speed, that is to say the selection of possible speeds for safety reasons.

Since the speed of the movable furniture part can be freely selected by the user, there is no danger for him of being injured by a furniture part that is movable too quickly. It can also be provided that the force exerted by the drive unit is less than the inhibiting forces - preferably zero Newton (N) - so that the movable furniture part comes to a standstill after a distance determined by the difference between the driving force and the inhibiting forces and its mass , The user must then act manually to accelerate the movable furniture part.

Of course, it could also be provided that there is no initial acceleration of the movable furniture part, so that the user has to move the movable furniture part manually over the entire distance to be covered by the movable furniture part.

The exemplary embodiments have in common that after an initial acceleration phase, if any, the movable furniture part does not appear to be propelled by the user even though the drive unit is active. The drive unit is thus electronically disengaged, but is structurally permanently connected to the movable furniture part, which means that it can be braked immediately if necessary, ie in the event of a collision.

Even if there is a collision of the movable furniture part with an object, the electronic decoupling of the drive unit according to the invention is advantageous compared to a simple shutdown of the drive unit after the initial acceleration phase, since the drive unit immediately, i.e. without the prior art by switching on the Drive unit-related time delay is available to react to a detected collision.

In a particularly preferred embodiment of the invention, the force is regulated to the predetermined value by regulating the current supplied to the drive unit, the current strength being determined by regulating the terminal voltage applied to the drive unit. In this exemplary embodiment, the collision detection could be implemented as follows:

The instantaneous increase in the current intensity caused by the collision is recognized by the control loop, which then regulates the current intensity back. This is done by lowering the terminal voltage. If the terminal voltage drops below a predetermined or predeterminable value, this is recognized as a collision. Suitable measures can now be taken, such as braking the movable furniture part. The collision can also be detected, for example, by monitoring the speed of the movable furniture part or by measuring the current supplied to the drive unit 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 occurring between the movable furniture part and the collision object, which the drive unit attempts to overcome. A drop in the terminal voltage of the drive unit could also be monitored, which is due to the fact that the speed of the movable furniture part and thus the voltage suddenly drops in the event of a collision.

It could also be monitored whether the movable furniture part reaches 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 the movable furniture part collides with an object, suitable measures, such as bringing the movable furniture part to a standstill or slightly moving the movable furniture part back, can be initiated.

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

If it is provided that the force is regulated to the predetermined value by regulating the current supplied to the drive unit, the current strength being determined by regulating the terminal voltage applied to the drive unit, the current strength required for a constant speed can also be determined in such a way that the movable furniture part is speed-controlled to this speed and when the speed is reached the current strength measured at that time is measured. During the subsequent section, on which the movable furniture part is driven with a force regulated to a predetermined value, the current strength thus determined is supplied to the drive unit, for example by specifying a suitable terminal voltage, for the drive unit.

Provision can also be made for the predetermined value of the force exerted by the drive unit to accelerate the movable furniture part. This would be Particularly advantageous for long distances to be covered by the movable furniture part in order to shorten the time required for this. If the resulting acceleration is not too great, the impression of a non-driven furniture part is still approximately given. In any case, the advantageous security aspects are fully preserved.

To simplify the design, provision can be made for the force to be determined directly in the drive unit. This can be, for example, a measurement of the current intensity supplied to the drive unit, which is directly proportional to the torque exerted by the drive unit. This is in a known manner in connection with the force exerted on the movable furniture part.

If the drive unit exerts force on the movable furniture part, for example via a gear mechanism which drives a roller with radius r, the roller driving the movable furniture part via a rope or toothed belt guided over it, the torque M results from the formula

M = Γ.CI,

where 1 is the current supplied to the drive unit, r is the gear reduction ratio and C is a machine 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 force exerted by the drive unit on the movable furniture part can also be determined 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 naturally does not have to be arranged in the drive unit.

Further advantages and details of the invention result from the following description of the figures. Show:

Fig. 1 to 3 embodiments of furniture, the invention

Process is realized in different ways, 4a-d to 6a, 6b, the current 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 and the current strength 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 depending on the

Time for an exemplary opening and closing process.

1 shows, in schematic form, a piece of furniture 1 with a plurality of movable furniture parts 2, the uppermost movable furniture part 2 being shown as being drawn out. A drive unit 3, which in this exemplary embodiment is an electric motor, as well as a roller 9 and a toothed belt 10 guided over it, can also be seen in the detailed illustration. The drive unit 3 drives the roller 9 and thus the toothed belt 10. The movable furniture part 2 is moved in a known manner by the toothed belt 10. In the exemplary embodiment shown in FIG. 1, the drive unit 3 contains a current measuring device (not shown) for determining the force exerted by the drive unit 3 on the movable furniture part 2.

The embodiment of FIG. 2 differs from that of FIG. 1 in that the force is not determined by a current measuring device integrated in the drive unit 3, but by a mechanical force sensor 4 contacting the toothed belt 10. For easier identification, 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 the roller 9 for better visibility.

In the embodiment shown in FIG. 3, a torque sensor 5 is provided to determine the force. For easier identification, 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 the roller 9 and the torque sensor 5 for better visibility.

4a and 4b now show on the basis of the current intensity I supplied to the drive unit 3 or the speed v of the movable furniture part 2, depending on the Activation of the drive unit 3 past time t an exemplary embodiment of the method according to the invention for driving the movable furniture part 2:

During a first period of time ti, in which the movable furniture part 2 covers the section Si upstream of the closed end position, the drive unit 3 is speed-controlled to accelerate the movable furniture part 2 from standstill. During the time tj, therefore, the current intensity I supplied to the drive unit 2 increases, which, as shown in FIG. 4b, causes an increase in the speed v of the movable furniture part 2.

After the time ti has elapsed, the force exerted by the drive unit 3 on the movable furniture part 2 is regulated to a predetermined value. In this exemplary embodiment, this is done by regulating the current intensity I to the predetermined value l ₀ during the period t ₂ in which the movable furniture part 2 covers the section S ₂ if there is no collision with the constant speed v ₀ . The current intensity I is regulated by specifying the terminal voltage applied to the drive unit 3.

After the period t ₂ , the movable furniture part ₂ comes close to its open end position, which can be detected, for example, by sensors, not shown.

Is carried out for deceleration of the movable furniture part 2 during the time period t ₃ again a speed control of the drive unit 3 as shown in Fig. 4a. This leads to the speed curve shown in FIG. 4b. After the total time t, + t ₂ + t ₃ , the movable furniture part 2 is in its open end position if there is no collision.

4c and 4d show the exemplary embodiment of FIGS. 4a and 4b with the difference that there is a manual intervention by a user, not shown, during the time periods t _A and t _B :

During the period t _A , the user exerts pressure on the movable furniture part 2, as a result of which its speed v ₀ drops to a lower value v _A. Since the drive unit 3 compensates the forces that inhibit the movement of the movable furniture part 2, the movable furniture part 2 continues to move uniformly at this lower speed v _A. During the period t _B , the user exerts tension on the movable furniture part 2, whereby its speed v _{A increases} to a higher value v _B. Since the drive unit 3 compensates the forces that inhibit the movement of the movable furniture part 2, the movable furniture part 2 continues to move uniformly at this higher speed v _B.

5a and 5b show a further exemplary embodiment of the method according to the invention, which differs from the exemplary embodiment illustrated in FIGS. 4a and 4b in that a larger offset l ₀ (that is to say a current intensity I different from 0) is selected. As a result, the movable furniture part 2 experiences an acceleration during the period t ₂ in which it covers the section S ₂ .

The exemplary embodiment of the invention shown in FIGS. 6a and 6b differs from the previous exemplary embodiments in that after the first period of time the current intensity I is regulated to the value 0, so that the force exerted by the drive unit 3 on the movable furniture part 2 is also regulated is regulated to the value 0 N. The drive unit 3 remains active. As shown in FIG. 6b, the movable furniture part 2 runs out under the influence of the frictional forces during the period t ₂ and remains in a position located between the closed and the open end position.

7a to 7d show an exemplary embodiment of the method according to the invention in the event of a collision of the movable furniture part 2 with an object 7:

As FIG. 7c shows, the current intensity I was regulated to the value l ₀ after the time period t _t in which the speed was regulated, at which the movable furniture part 2 maintains a constant speed v ₀ (FIG. 7 d). Currently _c t there is shown in Fig. 7a and 7b shown collision of the moveable part 2 with the schematically shown object 7, which, as shown in Fig. 7c, causes a momentary increase of the current I l from the value _0. The amount and duration of the increase were shown as exaggerated. The current intensity I is then regulated back by lowering the terminal voltage applied to the drive unit 3. The terminal voltage falls below a predetermined value, which is recognized as a collision. In response to this, the movable unit 2 is immediately braked by the drive unit 3, so that the damage occurring in the collision is minimized. This is done by a known reversal of the polarity of the terminal voltage. 8a shows an opening process as an example.

A speed-controlled acceleration takes place between t ₀ and ti. At time t ₀ , the amount v _{0 of} the speed of the movable furniture part 2 caused by the user pulling 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 ι of the minimum speed (here: | = 0.12 m / s) is reached at the time ^.

Once the minimum speed has been reached, the motor current is measured and the current level is controlled (corresponds to the torque M). The measured value of the current intensity I serves as the target value l ₀ for the current control.

If the friction changes during this movement sequence (for example due to load-dependent reductions 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 friction, both a minimum speed _value v _12ιrnln and a maximum speed _value v ₁₂ , m _{ax are} monitored (here: v _12ιrnin = 0.2 m / s, v _12l maχ = 0.25 m / s). If the limit values are exceeded or undershot, the setpoint value l _{0 of} the motor current I is incrementally reduced (for example by Δl = 15.6 mA every 2 ms) until a speed between the limit values is reached.

The current increment Dl is Δl = 15.6 mA. This corresponds to a force differential ΔF of ΔF = 0.4 N. The maximum value of the current strength l ₂ , m _a χ and the associated force F ₁₂ , m _ax are l ₂ , _m ax = 530 mA and F ₂ , _ma χ = 14 N . lι be the minimum values _2, min ⁼ 340 mA and

Fι ₂ , 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 safe comes to a stop before the end position. For example, Δs = 130 mm. After the calculation of a ₂ , a switch is made from the regulation of the current intensity I to the regulation of the speed (setpoint value of the speed is reduced in accordance with the deceleration). If the minimum opening speed v _{3 is} reached at t ₃ , the movable furniture part 2 is moved at this speed (here: v ₃ = 0.065 m / s) to the end stop.

FIG. 8b shows a closing process analogous to the opening process shown in FIG. 8a. For safety reasons, the speeds were chosen to be somewhat lower and the braking distances somewhat larger.

The speed v _{0 is} measured at time t ₀ . The acceleration a ₀ is a ₀ = 1.4 m / s ² . The speed | is v, = 0.68 m / s.

At time t ₁ were for the minimum value of the speed v _12, _m i _n = 0.12 m / s and selected for the maximum value of the speed v _12ιlτlax = 0.125 m / s.

The current increment Δl is Δl = 15.6 mA. This corresponds to a force differential ΔF of ΔF = 0.4 N. The maximum permissible current l ₁₂ , _max and the associated maximum force F _{12, max} on the movable furniture part 2 are l ₂ , _max = 690 mA and F ₁₂ , _max = 18 N. The minimum values are lι ₂ , _m ι _n = 330 mA and Fι ₂ = 9 N.

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

From time t ₃ the speed is v ₃ = 0.065 m / s until time t ₄ the end stop is reached.

Claims

claims:

1. A method for driving a movable furniture part, in particular a drawer, by an, in particular electrical, drive unit, characterized in that at least over a section (S ₂ ) of the path (S) to be covered by the movable furniture part (2), the drive unit (3 ) force exerted on the movable furniture part (2) is regulated to a predetermined value.

2. The method according to claim 1, characterized in that the predetermined value is zero newtons (N).

3. The method according to claim 1, characterized in that the predetermined value causes a constant speed of the movable furniture part (2).

4. The method according to claim 1, characterized in that the predetermined value causes an acceleration of the movable furniture part (2).

5. The method according to any one of claims 1 to 4, characterized in that the movable furniture part (2) is driven at least on a partial distance (S ^) of the path to be covered by the movable furniture part (2) (S) in a speed-controlled manner.

6. The 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 a section upstream of the closed end position (Si) and / or on a section upstream of the open end position (S ₃ ) of the path (S) to be covered by the movable furniture part (2) is driven in a speed-controlled manner.

7. The method according to any 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.

8. The method according to any one of claims 1 to 7, characterized in that the determination of the force takes place directly in the drive unit (3).

9. The method according to any one of claims 1 to 8, characterized in that the force is determined by a mechanical force sensor (4).

10. The method according to any one of claims 1 to 8, characterized in that the force is determined by a mechanical torque sensor (5).

11. The method according to any one of claims 1 to 8, characterized in that the force is determined by a current measuring device (6).