Furniture drive for moving a furniture front part

A furniture drive includes a main part and an actuator arm rotatably mounted on the main part about a first rotational axis. The actuator arm has multiple levers, and a securing interface arranged on an imaginary securing interface plane and via which the furniture front part can be secured to the actuator arm. The actuator arm can be moved continuously with respect to the first rotational axis between a first rotational position, which corresponds to a closed position of the furniture front part that can be secured to the actuator arm and which can be assigned a rotational angle α of 0°, and a second rotational position, which corresponds to a maximum open position of the furniture front part that can be secured to the actuator arm and which can be assigned a rotational angle α greater than 0°.

BACKGROUND OF THE INVENTION

The invention relates to a furniture drive for moving a furniture front part relative to a furniture carcass. The invention furthermore relates to a piece of furniture comprising a furniture carcass, a furniture front part and at least one such furniture drive. And finally, the invention relates to a method for moving a furniture front part relative to a furniture carcass of such a piece of furniture.

FIGS.1aand1bshow a furniture drive101according to the state of the art in a top view from the side. The furniture drive101comprises a main body104that can be fastened to a furniture carcass and an actuating arm105, which is mounted rotatable about a first axis of rotation106and a second axis of rotation115on the main body104. The actuating arm105has several levers107,108and109connected to each other in an articulated manner, wherein levers107and109are connected to each other via a pivot point144and levers108and109are connected to each other via a pivot point143. Levers107,108and109form two effective lever arms145and146, which run between the pivot points115and143on one side and106and144on the other side. PartialFIG.1bshows an abstracted schematic representation of lever arms145and146.

A disadvantage of this furniture drive according to the state of the art is that, when the furniture drive is used in a furniture carcass together with a further furniture drive in order to move a furniture front part relative to the furniture carcass, it needs to be coupled to the further furniture drive via a synchronization rod in order to synchronize a rotational movement of the actuating arms with each other and thus stabilize the system composed of the two furniture drives and the furniture front part. Without the synchronization rod, the system would be in an unstable state in particular at the beginning of the opening movement of the furniture front part.

However, the synchronization rod is also problematic because it takes up part of the interior which should actually be available as storage space for items to be stowed. Moreover, the synchronization rod is not very aesthetically appealing.

SUMMARY OF THE INVENTION

The object of the present invention is to specify a furniture drive that is improved compared with the state of the art, a piece of furniture with a furniture drive improved in such a way and a method for moving a furniture front part relative to a furniture carcass of such a piece of furniture, in which the above-described disadvantages are remedied, wherein in particular the use of a synchronization rod can be dispensed with and a stable system composed of two furniture drives and a furniture front part can nevertheless be realized.

In the furniture drive according to the invention, the levers of the actuating arm are arranged relative to one another such that a gradient f′ (α) of the function f is greater than 0.2, preferably greater than 0.3, at least over a rotational angle range of the actuating arm between 0° and 25°, preferably over the whole rotational angle range of the actuating arm.

The invention is based on the finding that, starting from a threshold value of the gradient f′ (α) of the function f, a furniture drive can be realized which has a sufficiently high stability in particular at the beginning of the opening movement, with the result that, in the case of an arrangement composed of two furniture drives which are used in a piece of furniture to move a furniture front part relative to a furniture carcass, an additional synchronization mechanism can be dispensed with. Below this threshold value the arrangement is unstable, as is known from the state of the art, above the threshold value the arrangement is stable.

This set of facts is further illustrated in the course of the description of the figures with reference toFIGS.6aand6b.

According to a preferred embodiment, the levers of the actuating arm form a four-pivot point geometry, wherein one of the four pivot points of the four-pivot point geometry corresponds to the at least one first axis of rotation of the actuating arm. The four pivot points of the four-pivot point geometry of the levers of the actuating arm are arranged relative to one another such that a gradient f′ (α) of the function f is greater than 0.2, preferably greater than 0.3, at least over a rotational angle range of the actuating arm between 0° and 25°, preferably over the whole rotational angle range of the actuating arm. Furniture drives with such a four-pivot point geometry are particularly suitable for implementing a pivoting-up movement of a furniture front part relative to a furniture carcass about at least one horizontal axis.

Alternatively or additionally, it has proved to be advantageous for the actuating arm to be mounted rotatable about at least one second axis of rotation on the main body, wherein the main body of the furniture drive has a front opening through which the actuating arm protrudes at least in areas at least in the maximum open position. The second axis of rotation has a smaller normal distance from the front opening than the first axis of rotation, and/or the main body of the furniture drive has a top side which faces a top panel of the furniture carcass when the furniture drive is fastened to the furniture carcass. The second axis of rotation has a smaller normal distance from the top side than the first axis of rotation. In comparison to that, the second axis of rotation115of the furniture drive101according toFIG.1a, known from the state of the art, has a larger normal distance from the front opening.

In this connection, with a four-pivot point geometry of the levers of the actuating arm, it has also proved to be advantageous for the second axis of rotation to correspond to a pivot point of the four-pivot point geometry.

Further advantageous embodiments are characterized by the fact that the actuating arm comprises at least three levers connected to each other in an articulated manner, and/or comprises at least one angled lever, preferably wherein two sections of the angled lever form an angle of substantially 90° relative to one another, and/or at least two of the provided levers of the actuating arm are arranged nested in one another in at least one rotational position, preferably in every rotational position, of the actuating arm, with the result that the two levers are formed substantially gap-free in a top view from the side, and/or at least one lever is formed U-shaped in a cross section and a further lever can be arranged or is arranged between the vertical bars of the U shape at least in sections. The nested arrangement and/or the arrangement in sections within the U shape make it possible in particular to form the actuating arm symmetrical with respect to an imaginary center plane, as a result of which the same actuating arm and thus the whole furniture drive can be used irrespective of the side wall of a furniture carcass in and/or to which the furniture drive is fastened.

A technically simple and at the same time stable lever arrangement can be achieved in that the actuating arm has at least one first lever and one second lever, via which the actuating arm is rotatably connected to the main body, and at least one third lever, on which the fastening interface is formed, wherein the first lever and the second lever are connected to the third lever in an articulated manner.

The installation of a furniture front part on a furniture carcass can be greatly simplified in that at least one, preferably at least two, of the levers of the actuating arm can be detachably connected to the main body of the furniture drive.

It has proved to be advantageous for the furniture drive to have at least one energy storage mechanism, preferably having at least one spring element and preferably mounted on the main body, via which a force can be applied to the actuating arm in order to compensate for a weight of the furniture front part that can be fastened to the actuating arm.

In this connection, it makes sense for a transfer mechanism to be provided, with which a force that can be stored in the at least one energy storage mechanism can be transferred to the actuating arm. Preferably, the transfer mechanism comprises at least one intermediate lever, and the at least one energy storage mechanism is connected to the at least one intermediate lever via a preferably adjustable force linkage point, and/or comprises at least one pressure piece and at least one positioning contour, on which the at least one pressure piece can be displaceably supported. Preferably, the at least one pressure piece is arranged on at least one intermediate lever of the transfer mechanism and the at least one positioning contour is arranged on the actuating arm, or vice versa.

As stated at the beginning, protection is also sought for a piece of furniture comprising a furniture carcass, a furniture front part and at least one furniture drive according to the invention. The main body of the at least one furniture drive is fastened to the furniture carcass, preferably in and/or on a side wall of the furniture carcass, and the furniture front part is fastened to the actuating arm of the at least one furniture drive via the fastening interface.

The advantages of the furniture drive according to the invention come into effect above all when the piece of furniture comprises at least one further furniture drive connected to the furniture carcass and the furniture front part, wherein the two furniture drives are connected to each other only via the furniture front part and the furniture carcass, this means that a synchronization mechanism separate from the furniture front part, such as e.g. a synchronization rod known from the state of the art, can be dispensed with.

An advantageous embodiment of the piece of furniture is characterized by the fact that an instantaneous center of rotation of the furniture front part or of the lever arrangement of the levers of the actuating arm can be moved along an imaginary curve in space relative to the furniture carcass when the furniture front part is moved between the closed position and the maximum open position. The furniture carcass has a top panel, and an end point of the curve of the instantaneous center of rotation, which corresponds to the closed position, is less than 500 mm, preferably less than 250 mm, away from the top side of the top panel, and/or the furniture carcass has a front face that faces the furniture front part in the closed position, and an end point of the curve of the instantaneous center of rotation, which corresponds to the closed position, is less than 75 mm, preferably less than 50 mm, away from an imaginary extension of the front face upwards beyond the furniture carcass.

In the case of a planar movement of a rigid body, the instantaneous center of rotation is that point in space about which the body can be regarded as only rotating at that instant. In the case of a planar movement of a rigid body with a translational movement and a rotary movement, these are combined into a pure rotational movement about the pivot point at that instant, which is referred to as the instantaneous center of rotation.

During the movement of the furniture front part, the instantaneous center of rotation changes further in every covered position. If these positions are determined, the result is a path in relation to a space-fixed reference system, in the present case to the stationary furniture carcass, on which the instantaneous center of rotation runs. The instantaneous center of rotation of the furniture front part can be determined for every arbitrary point of the furniture front part or also for points of other component parts which are connected to the furniture front part.

With reference to the lever arrangement of the levers of the actuating arm in the case of a four-pivot point geometry, the instantaneous center of rotation can be determined as the point of intersection of the two effective lever arms.

It has now been proved that a particularly stable system can be achieved when the instantaneous center of rotation is arranged as close as possible to the fixed pivot points of the furniture drive, in particular at the beginning of the opening movement. The smaller the distance of the mentioned end point of the curve is from the instantaneous center of rotation, the more rigid and more stable is the arrangement that can be realized with the furniture drive. This set of facts is explained in even more detail in the course of the description of the figures with reference toFIGS.10aand10b.

Preferably, the furniture carcass comprises a cornice, wherein, in the case of a movement between the closed position and the maximum open position, the furniture front part can be moved unhindered around the cornice without an upper edge of the furniture front part that faces the cornice in the closed position colliding with the cornice, preferably wherein the furniture carcass has a top panel, and a top side of the cornice is between 75 and 100 mm away from the top side of the top panel, and/or the furniture carcass has a front face that faces the furniture front part in the closed position, and a front side of the cornice is between 40 and 75 mm away from an imaginary extension of the front face upwards beyond the furniture carcass.

It makes sense for the furniture carcass to have a front face that faces the furniture front part in the closed position, wherein, in the closed position, the furniture front part has a front part angle β of 0° relative to the front face, preferably wherein, in the maximum open position, the furniture front part has a front part angle β of between 60° and 80° relative to the front face.

Quite apart from the threshold value defined for the gradient f′ (α) of the function f, no piece of furniture is known from the state of the art which comprises a furniture carcass, a furniture front part and at least one furniture drive in which the main body of the at least one furniture drive is fastened to the furniture carcass, preferably in and/or on a side wall of the furniture carcass, and the furniture front part is fastened to the actuating arm of the at least one furniture drive via the fastening interface. An instantaneous center of rotation of the furniture front part or of the lever arrangement of the levers of the actuating arm can be moved along an imaginary curve in space relative to the furniture carcass when the furniture front part is moved between the closed position and the maximum open position, in which the furniture carcass has a top panel, and an end point of the curve of the instantaneous center of rotation, which corresponds to the closed position, is less than 500 mm, preferably less than 250 mm, away from the top side of the top panel, and/or the furniture carcass has a front face that faces the furniture front part in the closed position, and an end point of the curve of the instantaneous center of rotation, which corresponds to the closed position, is less than 75 mm, preferably less than 50 mm, away from an imaginary extension of the front face upwards beyond the furniture carcass, and wherein the furniture carcass comprises a cornice and, in the case of a movement between the closed position and the maximum open position, the furniture front part can be moved unhindered around the cornice without an upper edge of the furniture front part that faces the cornice in the closed position colliding with the cornice, preferably wherein the furniture carcass has a top panel, and a top side of the cornice is between 75 and 100 mm away from the top side of the top panel, and/or the furniture carcass has a front face that faces the furniture front part in the closed position, and a front side of the cornice is between 40 and 75 mm away from an imaginary extension of the front face upwards beyond the furniture carcass.

According to an advantageous embodiment, the piece of furniture has at least one further furniture drive connected to the furniture carcass and the furniture front part, wherein the two furniture drives are connected to each other only via the furniture front part and the furniture carcass.

And finally, protection is sought for a method for moving a furniture front part relative to a furniture carcass of a piece of furniture according to the invention, wherein the furniture front part is moved, starting from a closed position, in the direction of a maximum open position, and vice versa, preferably wherein the furniture carcass comprises a cornice and, in the case of a movement between the closed position and the maximum open position, the furniture front part is moved unhindered around the cornice without an upper edge of the furniture front part that faces the cornice in the closed position colliding with the cornice.

DETAILED DESCRIPTION OF THE INVENTION

FIGS.1aand1b, which show a furniture drive101according to the state of the art, have already been described at the beginning.

In comparison to that,FIGS.2aand2bshow an embodiment of a furniture drive1according to the invention for moving a furniture front part2relative to a furniture carcass3(see also the followingFIG.3), comprising a main body4that can be fastened to the furniture carcass3and an actuating arm5, which is mounted rotatable about at least one first axis of rotation6on the main body4.

The actuating arm5has several levers7,8,9connected to each other in an articulated manner.

The actuating arm5has a fastening interface11arranged in an imaginary fastening interface plane10via which the furniture front part2can be fastened to the actuating arm5. The fastening interface plane10is indicated by means of a dot-dashed line.

The actuating arm5can be moved continuously with respect to the at least one first axis of rotation6between a first rotational position and a second rotational position. The first rotational position corresponds to a closed position of the furniture front part2that can be fastened to the actuating arm5(and, particularly, the position of the first lever7when the fastening interface11and furniture front part2are in the closed position), and can be assigned a rotational angle α of 0°. The second rotational position corresponds to a maximum open position of the furniture front part2that can be fastened to the actuating arm5(and, particularly, the position of the first lever7when the fastening interface11and furniture front part2are in the maximum open position) and can be assigned a rotational angle α greater than 0°. The left-hand edge, in the figure, of the first lever7which is marked with a dashed line can be used, for example, as reference for the measurement of the rotational angle α. However, the rotational angle α can also be determined in relation to another axis of rotation and/or in relation to another reference. The rotational angle α is drawn in by way of example inFIG.5a.

During a rotational movement of the actuating arm5, the fastening interface plane10, and thus the furniture front part2that can be fastened to the actuating arm5, passes through different front part angles β. The front part angle β is drawn in by way of example inFIG.5a, and is the angle between a front face37of the furniture carcass3(seeFIG.3) and the fastening interface plane10.

Each rotational angle α of the actuating arm5can be assigned a front part angle β=f (α) of the fastening interface plane10using a function f, beginning with a front part angle β of 0°, which can be assigned to the rotational angle α of the actuating arm5of 0°.

In the embodiment represented, levers7,8,9of the actuating arm5form a four-pivot point geometry, wherein one of the four pivot points of the four-pivot point geometry corresponds to the at least one first axis of rotation6of the actuating arm5.

The actuating arm5is mounted rotatable about at least one second axis of rotation15on the main body4, and the main body4of the furniture drive1has a front opening16through which the actuating arm5protrudes at least in areas at least in the maximum open position. The second axis of rotation15is located a smaller normal distance17from the front opening16than is the first axis of rotation6, and the main body4of the furniture drive1has a top side18which faces a top panel19of the furniture carcass3when the furniture drive1is fastened to the furniture carcass3. The second axis of rotation15is located a smaller normal distance20from the top side18than is the first axis of rotation6.

The second axis of rotation15corresponds to a pivot point of the four-pivot point geometry of the levers7,8,9of the actuating arm5.

Compared with the furniture drive101according toFIGS.1aand1bknown from the state of the art, the distance between the two axes of rotation6and15of the furniture drive1is much smaller than the distance between the two axes of rotation106and115of the furniture drive101.

The actuating arm5comprises three levers7,8,9connected to each other in an articulated manner including one angled lever9, wherein two sections21,22of the angled lever9form an angle23of substantially 90° relative to one another.

Two of the provided levers7,8,9of the actuating arm5, namely levers7and8, are arranged nested in one another in at least one rotational position of the actuating arm5, with the result that the two levers7,8are formed substantially gap-free in a top view from the side. The first lever7is formed U-shaped in a cross section, and a second lever8can be arranged or is at least partially arranged between the vertical bars (legs) of the U shape.

The actuating arm5has the first lever7and the second lever8, via which the actuating arm5is rotatably connected to the main body4, and the third lever9, on which the fastening interface11is formed. The first lever7and the second lever8are connected to the third lever9in an articulated manner. For this, a first pivot point43, which connects levers7and9, and a second pivot point44, which connects levers8and9, are provided.

The two levers7and8of the actuating arm5can be detachably connected to the main body4of the furniture drive1.

InFIG.2b, the position of the two effective lever arms45and46relative to the main body4is again represented in the first rotational position of the actuating arm5, i.e. the closed position.

FIG.3shows an embodiment of a piece of furniture31with a furniture drive1. The piece of furniture31comprises a furniture carcass3, a furniture front part2and at least one furniture drive1. The main body4of the furniture drive1is fastened to the furniture carcass3, preferably in and/or on a side wall32of the furniture carcass3, and the furniture front part2is fastened to the actuating arm5of the at least one furniture drive1via the fastening interface11.

The piece of furniture31can also comprise at least one further furniture drive1connected to the furniture carcass3and the furniture front part2, wherein the two furniture drives1are connected to each other only via the furniture front part2and the furniture carcass3.

The furniture carcass3has a front face37that faces the furniture front part2in the closed position. In the closed position, the furniture front part2has a front part angle β of 0° relative to the front face37, while in the maximum open position, the furniture front part2has a front part angle β of between 60° and 80° relative to the front face37. This maximum open position is represented inFIG.3.

In addition to a top panel19, the piece of furniture31can also comprise a shelf47and/or a cornice39.

FIG.4shows the embodiment of the furniture drive1with an open casing, with the result that the inner workings of the furniture drive1can be seen.

The furniture drive1can have at least one energy storage mechanism24, preferably having at least one spring element25and preferably mounted on the main body4, via which a force can be applied to the actuating arm5in order to compensate for a weight of the furniture front part2that can be fastened to the actuating arm5.

As in the represented case, a transfer mechanism26can be provided, with which a force that can be stored in the at least one energy storage mechanism24can be transferred to the actuating arm5. The transfer mechanism26comprises at least one intermediate lever27, and the at least one energy storage mechanism24is connected to the at least one intermediate lever27via an adjustable force linkage point28.

The transfer mechanism26comprises a pressure piece29and at least one positioning contour30, on which the at least one pressure piece29can be displaceably supported. The at least one pressure piece29is arranged on the at least one intermediate lever27of the transfer mechanism26, and the at least one positioning contour30is arranged on the actuating arm5, or vice versa.

The furniture drive1can also comprise a damper48, with which a movement of the actuating arm5in the opening and/or closing direction can be damped.

FIGS.5a-5eshow the embodiment of the furniture drive1, wherein the actuating arm5is arranged in different rotational positions relative to the main body4, between a first rotational position, which corresponds to a closed position of the furniture front part2that can be fastened to the actuating arm5(partial figure a), and a second rotational position, which corresponds to a maximum open position of the furniture front part2that can be fastened to the actuating arm5(partial figure e). PartialFIGS.5b,5cand5dshow intermediate rotational positions.

If the front part angle β is plotted as a function of the rotational angle α, then the progression represented inFIG.6aresults (continuous line). The progression of the front part angle β of the furniture drive101known from the state of the art (dot-dash line) and the curves of a furniture drive with a 1-pivot point linkage (dashed lines) are represented in comparison to that.

If the derivative f′ (α) is calculated in each case and plotted against the rotational angle α, then the progressions represented inFIG.6bresult.

In the case of a furniture drive with a 1-pivot point linkage, the gradient is 1 at every point. In the case of the furniture drive101known from the state of the art, the front part angle β initially changes gradually and then increasingly sharply. In comparison to that, in the case of the furniture drive1the front part angle β changes comparatively sharply even at the beginning of the opening movement. This is realized in technical terms in that the levers7,8,9of the actuating arm5, or the four pivot points of the four-pivot point geometry of the levers7,8,9of the actuating arm5, are arranged relative to one another such that a gradient f′ (α) of the function f is greater than 0.2, preferably greater than 0.3, at least over a rotational angle range of the actuating arm5between 0° and 25°, preferably over the whole rotational angle range of the actuating arm5.

If the stabilities of the furniture drive with a 1-pivot point linkage, the furniture drive101known from the state of the art and a furniture drive1according to the invention are now compared, it can thus be established that the furniture drive with a 1-pivot point linkage is the most stable solution and the furniture drive101known from the state of the art is the least stable solution, which requires a synchronization mechanism. It has now been found, surprisingly for a person skilled in the art, that furniture drives1in which a gradient f′ (α) of the function f is greater than 0.2, preferably greater than 0.3, at least over a rotational angle range of the actuating arm5between 0° and 25°, preferably over the whole rotational angle range of the actuating arm5, already have a sufficiently high stability which makes it possible to dispense with the use of a synchronization mechanism separate from the furniture front part. In the specifically represented case, the gradient f′ (α) of the function f is above 0.4 in the whole rotational angle range of the actuating arm5.

FIG.7shows a comparative representation of the position of the furniture front parts2and102relative to the furniture carcass of a piece of furniture according to the state of the art (continuous lines) and a piece of furniture31according to the invention (dashed lines). It can be clearly seen that, in the case of the piece of furniture31according to the invention, the furniture front part2starts to rotate immediately at the beginning of the opening movement, whereas, in the case of the state of the art, the furniture front part is initially moved substantially parallel away from the front face of the furniture carcass. The cornice39is circumnavigated in both cases.

FIGS.8ato8fand9ato9f, in a comparison, show, on the one hand, the movement of the lever arms145and146in the case of a furniture drive101according to the state of the art and, on the other hand, the lever arms45and46in the case of a preferred embodiment of the furniture drive1according to the invention in the course of an opening movement starting from the closed position represented in partial figure a, i.e. the first rotational position of the actuating arm5, up until the maximum open position represented in partial figure f, i.e. the second rotational position of the actuating arm5.

It can be established that a dead center of the lever geometry is crossed at an earlier point in time in the course of the opening movement in the case of the furniture drive101.

InFIGS.9cand9d, the instantaneous center of rotation of the lever geometry is represented in space by way of example from the point of intersection of the two lever arms45and46. If the instantaneous center of rotation is plotted for each rotational position of the furniture drive1and101, then the curves134and34represented inFIGS.10a(for the furniture drive101) and10b(for the furniture drive1) result.

It emerges fromFIG.10bthat the instantaneous center of rotation33of the furniture front part2or of the lever arrangement of the levers7,8,9of the actuating arm5can be moved along an imaginary curve34in space relative to the furniture carcass3when the furniture front part2is moved between the closed position and the maximum open position. The furniture carcass3has a top panel19, and an end point35of the curve34of the instantaneous center of rotation33, which corresponds to the closed position, is less than 500 mm, preferably less than 250 mm, away from a top side36of the top panel19(drawn in as distance49in the figure). The furniture carcass3also has a front face37that faces the furniture front part2in the closed position, and an end point35of the curve34of the instantaneous center of rotation33, which corresponds to the closed position, is less than 75 mm, preferably less than 50 mm, away from an imaginary extension (i.e., a plane)38of the front face37upwards beyond (above) the furniture carcass3(drawn in as distance50in the figure).

In comparison to that, the distance149of the end point135of the curve134of the instantaneous center of rotation133from the top side136of the top panel119of the piece of furniture131in the case of the furniture drive101is approx. 1700 mm and the distance150from the imaginary extension138is approx. 190 mm and thus much greater, which results in an unstable arrangement, which needs to be stabilized with a synchronization rod.

In the enlarged partial views ofFIGS.10aand10b, the circumnavigation of the cornices139and39is additionally represented.

The furniture carcass3of the piece of furniture31comprises a cornice39, wherein, in the case of a movement between the closed position and the maximum open position, the furniture front part2can be moved unhindered around the cornice39without an upper edge40of the furniture front part2that faces the cornice39in the closed position colliding with the cornice39. Preferably, the furniture carcass3has a top panel19, and a top side41of the cornice39is between 75 mm and 100 mm away from the top side36of the top panel19(drawn in as distance12in the figure), and/or the furniture carcass3has a front face37that faces the furniture front part2in the closed position, and a front side42of the cornice39is between 40 and 75 mm away from an imaginary extension38of the front face37upwards beyond the furniture carcass3(drawn in as distance13in the figure).

InFIG.10a, the edge of the furniture front part102is provided with the reference number140, the top side of the cornice139is provided with the reference number141and the front side of the cornice139is provided with the reference number142.

No piece of furniture is known from the state of the art which fulfils both conditions, namely on the one hand a curve34of the instantaneous center of rotation33arranged very close to the fixed pivot points of the furniture drive1and, on the other hand, the possibility to circumnavigate an optionally present cornice39without colliding.