EP3267843B1 - Electromotive furniture drive - Google Patents

Description

The invention relates to an electromotive furniture drive for adjusting at least one furniture part of a piece of furniture with at least one drive unit, which has a drive motor, a gear and a spindle drive with a spindle acting on a driven member displaceable along a displacement path, and with a control board for controlling the drive motor. wherein on the control board limit switches are arranged, which are actuated via a coupled to the driven member control rod.

Such electromotive furniture drives are used to be able to adjust furniture parts such as a headboard or a footboard of a slatted frame or a backrest or a footrest of an armchair by electric motor. The furniture drives may e.g. be designed as individual drives with a drive unit or as double drives with two drive units. Double drives can be easily mounted on the furniture, for example, said slatted bed, by a respective pivot axis of the furniture is inserted into each one formed on the furniture drive axle mounts. For this purpose, the axle mounts are usually provided with cover slides, which can be removed in order to insert the pivot axis with a pivot lever in the axle can. After replacing the cover slide, the entire double drive is fixed to the axles. The drive units act independently on their spindle drive and the output member on the respective pivot lever for adjusting the furniture parts.

Such a double drive is for example from the document EP 2 002 148 B1 known. In this double drive, an elongated common housing is provided for the double drive, wherein the drive motors are each arranged outside in end portions of the housing and point the spindles inwardly to the center of the double drive. Output members with inserted spindle nut act on the pivot lever and thus the pivot axes of the furniture. Between the spindles a control board is arranged, are arranged on the limit switch or slide potentiometer, which are operated or moved via control rods depending on the position of the output members. The control rods are firmly connected to the output members. Due to the arrangement of the limit switches or slide potentiometer on the control board, the effort when wiring against a Minimized arrangement of these elements in the field of output members. The disadvantage, however, is that on the control board or in the region of the control board sufficient clearance for the movement of the control rods must be available.

It is therefore an object of the present invention to provide an electromotive furniture drive of the type mentioned, in which the space required for the movement of the control rods in the control board space is minimized and thus the largest possible part of the control board used for electrical and / or electronic components can be.

This object is achieved by an electromotive furniture drive with the features of the independent claim. Advantageous embodiments and further developments are specified in the dependent claims.

An electromotive furniture drive of the type mentioned above is characterized in that the control rod is designed as a tow bar, which is coupled only in end portions of the displacement path of the output member to the output member. Trained as a tow bar, the control rod is not moved over the entire displacement of the driven member, but is only moved when the driven member is located in the end portions of the displacement. Accordingly, the space to be kept free for the movement of the control rod is minimized on or in the vicinity of the control board, whereby more space is available for electrical and / or electronic components on the control board. Nevertheless, by the movement of the tow bars on approach of the output member at the limits of its displacement path, a Endlagenabschaltung done with the arranged on the control board limit switches.

In an advantageous embodiment of the furniture drive such a sectional coupling between the tow bar and the output member is realized mechanically simple in that the tow bar has a driver which is moved in the end portions of the displacement of stops on the output member in one or an opposite direction. Advantageously, the tow bar is associated with a return spring, which exerts a restoring force in the direction of a neutral position of the tow bar upon deflection in each of the possible directions. In a cost-effective and material-saving design, the return spring is a w-shaped spring with two spring arms, which is fixed in a central region on the housing. The spring arms engage around a part of the tow bar, for example a correspondingly shaped cam, wherein, depending on the direction of the deflection, one or the other spring arm pushes the cam back in the direction of the neutral position. In this case, a preferably positioned between the spring arms stop for the spring arms on the housing is provided, is achieved by the fact that upon deflection of the tow bar from the neutral position only one of the spring arms exerts force on the tow bar. In this case, each of the spring arms is preferably biased and is under the action of force before the stop.

Alternatively to the w-shaped spring with two spring arms other types of springs, such as coil springs, coil springs, leg springs or leaf springs can be used. When using these types of springs, a stop is preferably provided in each case, which in turn can be arranged on the housing or is formed integrally with the housing. An alternative stop is integrated in the spring system itself when the furniture drive is provided with a spring system as a compact and self-sufficient unit.

In a further advantageous embodiment of the electromotive furniture drive, the tow bar switching cam to actuate the limit switch during deflection. In this case, the switching cams are preferably arranged on one side of the control board and the other sections of the tow bar on the opposite side of the control board. In the control board a slot-like recess is provided, in which the tow bar is guided and by which the movement of the tow bar is transmitted from one side of the control board to the switching cam on the other side of the control board. The control board also assumes the additional function of guiding the tow bar. In addition, in addition, a further guidance of the tow bar within the housing, preferably by elements of the housing, e.g. By stiffening ribs, be provided.

In a further advantageous embodiment of the electromotive furniture drive, the drive member is a linearly displaceable between a fully retracted and a fully extended position pressure slide, the approach rod to the fully retracted or the fully extended position the tow bar from the neutral position in one or an opposite direction deflects. Preferably, the pressure slide on transverse ribs, which form stops for the driver of the tow bar. The linear sliding movement of such a pressure slide, with a Pressure plate acts on the pivot lever of a pivot axis of the furniture, is transmitted only when approaching the respective end of the displacement on the tow bar when the driver of the tow bar is in engagement with one of the transverse ribs.

In a further advantageous embodiment of the electromotive furniture drive is designed as a double drive with two drive units, wherein both drive units are arranged longitudinally one behind the other in a common housing and wherein longitudinally opposite end portions of the housing axle mounts for each pivot axis of the furniture, each on a Output member acts, are formed and wherein each drive unit is assigned a tow bar and the control board has limit switches for both drive units.

Spindles and / or the output members of the two drive units are particularly preferably designed to be of different lengths, so that the drive motors are spaced differently from the axle receptacle assigned to them for the respective pivot axis, wherein different sized installation spaces are formed adjacent to the spindles and wherein the control board is in the larger of the two installation spaces is arranged.

In known from the prior art double drives both drive units are formed with the shortest possible spindle whose length is comparable to the length of the shorter of the spindles according to the present advantageous embodiment of the double drive. As a result, apart from the end regions of the double drive, in which the pivot axes are accommodated, the available interior of the housing is divided into three construction spaces, one above the spindles and a third installation space between the two drive motors. Accordingly, the space available in the housing according to the prior art in about three equal sections divided, whereas in this embodiment of the double drive, the space between the drive motors is reduced and at least one of the sections in the range of one of the spindles is thereby increased. Preferably, both drive units can be arranged with their drive motors adjacent and at a small distance from each other, whereby the installation space lying between the motors in favor of a larger installation space in the region of the extended spindle is eliminated. Even if the total available space does not increase with the same length of the furniture drive, it is less divided and is available for recording the control board ready, which can be made correspondingly larger than other layouts within the dual drive. This makes it possible, for example, advantageously to use a single control board on which a power supply and a control device for the drive motors are arranged, whereby the wiring complexity is reduced during assembly.

Preference is given to the use of a one-piece towing bar, which can be divided into several sections. A first section can be coupled to the output member. The coupling may e.g. be formed by actuating edges of the first section. A second section is located near the limit switches for actuating the same. Another section connects the first and the second section. This can be elongated and rectilinear. Alternatively, he is cranked trained. Preferably, a plastic is used for this section. Alternatively, wire-shaped or rod-shaped sections are conceivable which are connectable to the first and second sections.

Different lengths of travel of the output member can be achieved by the further section is adjusted accordingly in its length or by a length adjustable further section is used. This applies both to a one-piece and a multi-part design of the tow bar. Likewise, the use of different length first or second sections would be conceivable to predetermine the respective cut-off point.

In one embodiment, the first section is designed in several parts. In this case, at least one actuating edge is displaceably arranged on the first section, so that the shut-off point for switching off the furniture drive is variable. Alternatively, the at least one actuating edge to the first portion is firmly attached, which can preferably be done in the manufacture of the furniture drive. In other words, different distances between the actuating edges relative to one another or at least one actuating edge relative to the second section can be generated in the simplest manner, in order to predetermine the switch-off point of the furniture drive and the associated displacement path of the output member.

Figur 1, 2

jeweils eine isometrische Ansicht eines Möbelantriebs aus zwei unterschiedlichen Blickrichtungen;

Figur 3

eine isometrische Ansicht des Möbelantriebs der Figuren 1 und 2 mit geöffnetem Gehäuse;

Figur 4

eine Seitenansicht des Möbelantriebs der Figuren 1 und 2 mit geöffnetem Gehäuse;

Figur 5

eine weitere isometrische Ansicht des Möbelantriebs der Figuren 1 und 2 mit geöffnetem Gehäuse;

Figuren 6-8

jeweils eine isometrische Detailansicht des Möbelantriebs;

Figur 9

eine isometrische Darstellung eines Druckschiebers und eines Druckkopfes des Möbelantriebs der Figuren 1 bis 8;

Figur 10

drei Teilbilder mit jeweils einer Draufsicht auf einen Teil des Druckschiebers mit Druckkopf in verschiedenen Relativpositionen zueinander; und

Figur 11

eine Draufsicht auf Anzahl von Möbelantrieben in einer Verpackungseinheit.

The invention will be explained in more detail using an exemplary embodiment with reference to figures. The figures show:

FIG. 1, 2

in each case an isometric view of a furniture drive from two different viewing directions;

FIG. 3

an isometric view of the furniture drive FIGS. 1 and 2 with the housing open;

FIG. 4

a side view of the furniture drive the FIGS. 1 and 2 with the housing open;

FIG. 5

Another isometric view of the furniture drive FIGS. 1 and 2 with the housing open;

Figures 6-8

in each case an isometric detailed view of the furniture drive;

FIG. 9

an isometric view of a pressure slide and a print head of the furniture drive the FIGS. 1 to 8 ;

FIG. 10

three partial images, each with a plan view of a portion of the pressure slide with printhead in different relative positions to each other; and

FIG. 11

a plan view of the number of furniture drives in a packaging unit.

In the FIGS. 1 and 2 an embodiment of a furniture drive according to the application is shown in each case in an overall isometric view from two different directions of view. In these as in all subsequent figures, like reference numerals each show the same or equivalent elements.

The furniture drive has a housing 10 which, with respect to its basic shape, is substantially parallelepiped-shaped with a longitudinal extent in a first direction, hereinafter referred to as the x-direction, which clearly exceeds the extent in the y- or z-directions perpendicular thereto.

The housing 10 is constructed from two housing half shells, a first housing half shell 11 and a second housing half shell 12, wherein a dividing line between the two housing half shells 11, 12 in the xy plane runs. Preferably, the housing half shell 11, 12 are made of plastic in an injection molding process.

The housing 10 shown in this embodiment is bolted to connect its housing half shells 11,12. For this purpose, screw holes 112 arranged in clamping recesses 111 and 121, respectively, are provided in the first housing half shell 11 or screw domes 122 in the second housing half shell 12. Alternatively and / or additionally, the dividing line between the housing halves 11, 12 cross-over and latching with these connecting terminals can be clipped into the clamping grooves 111 and 121, respectively. In addition to the screw connections arranged in the clamping recesses 111, 121, further screw holes 112 may be provided, such as in FIG FIG. 1 can be seen in the lower middle region of the first housing half shell 11.

On side surfaces 113 and 123 of the housing 10 slightly recessed connection troughs 114 and 124 are arranged in which connections and / or display and control elements are positioned for the electromotive furniture drive. Even with slightly curved side surfaces 113, 123, a flat surface is provided within the wells, which simplifies the arrangement of terminals and controls. The connection troughs 114, 124 also protect the connections and display and operating elements during transport or assembly.

As in particular in FIG. 2 As can be clearly seen, a motor dome 125 protrudes beyond the side surface 123 on the second housing half shell 12. The motor dome 125 covers laterally over the side surface 123 protruding motor housing, wherein in the illustrated embodiment, a single motor dome 125 is provided which engages over the housing of two juxtaposed drive motors.

In addition to a screwing or clamping of the housing 10, other connection methods are alternatively possible, in particular a welding, riveting or gluing the housing half shells 11, 12. A welding housing half shells 11, 12, which are made of thermoplastic material, can be carried out in an ultrasonic process. Particularly advantageous is a welding process, are heated in the abutting surfaces of the housing halves 11, 12 prior to assembly until the plastic material melts at least in a near-surface layer. In a next step will be the housing half shells under the action of force fit together until the plastic has become solid again and has connected to the plastic of the other housing half shell 11, 12. For accurate positioning of the housing half shell 11, 12 with each other can be provided on the housing half shell 11, 12 in one another or interlocking webs or pins.

For heating the plastic surfaces radiant heat may be generated by heating elements, e.g. Infrared emitters are supplied. Alternatively and preferably, a so-called hot gas or hot air welding method can be used, in which a hot gas is directed via a nozzle distribution system exactly localized on the connection points. An advantage of the welding method by preheating the connection points with respect to ultrasonic welding is that targeted connections between the housing half shells 11, 12 can also be formed in the interior of the housing. Thus, a connection in the region of force-receiving or force-transmitting housing sections take place inside the housing. Such housing sections are provided in particular in the region of gears and / or the axle 13. They can also be designed so that they bring about a centering or positioning of the housing half shell 11, 12 with each other.

Another advantageous type of connection is hot riveting. In this method, which is suitable for plastic housing half-shells, bolt-shaped rivet elements are arranged on one of the housing half shells, which penetrate corresponding openings or openings of the other housing half shells when assembling the housing. Thereafter, in the so-called Heißgasnietverfahren the head of the rivet element is heated and pressed with a cold punch to a rivet head. An advantage of this is that the geometry of the rivet element can be chosen freely. In addition to the aforementioned bolts and larger elements can be used in tongue or tab shape, which allow a large-scale power transmission between the two housing halves.

In the end regions (viewed in the direction of longitudinal extent) of the housing 10, axle receptacles 13 are arranged, in each of which a pivot axis of a piece of furniture oriented in the z-direction is mounted. To insert the pivot axis in the axle 13 each have a removable slider 14 is provided, which engages over the axle 13. The slider 14 is in correspondingly shaped and undercut grooves of the housing halves 11, 12 pushed. Preferably, an insertion in the z-direction is provided, wherein in addition a locking between the sliders 14 and the housing half-shells 11, 12 may be provided.

The pivot shafts used in the Achsaufnahmen 13 have a then within the housing 10 lying pivot lever, which is acted upon by the furniture drive shown with force, whereby the pivot shafts are rotated to adjust furniture parts. A typical application is the furniture drive shown in connection with a slatted bed of a bed as furniture. The two pivot shafts are connected to a head or a foot part of the slatted frame, which can be raised or lowered by pivoting the pivot shafts accordingly. The furniture drive actuates the pivot shafts and is fixed to them at the same time. A beyond Bestbestigung the furniture drive on the furniture is not required. In operation, the furniture drive is essentially oriented so that the drawn xz plane is horizontal and the xy plane is vertical.

In the Figures 3 and 4 is an overall view of the furniture drive the FIGS. 1 and 2 illustrated, wherein the first housing half shell 11 (see. FIGS. 1 . 2 ) is removed to provide insight into the internal structure of the furniture drive. The FIG. 3 is an isometric oblique view from the point of view, which is also in FIG. 1 is taken. The FIG. 4 shows the furniture drive in a side view on the xy plane.

The superimposed outer edges of the housing halves 11, 12 form abutment surfaces 127, which can be profiled so that a seal of the two housing halves 11, 12 to each other. This is possible, for example, by forming tongue and groove on the abutment surfaces 127. In addition, the abutment surfaces 127 of the two housing halves 11, 12 may be glued together or it may be an elastic seal between. If a connection of the two housing half shells 11, 12 by a welding process, for example, the aforementioned hot gas welding, a profiling, for example, a chamfer may be provided by which prevents a weld protrudes outward, or by which a supernatant is reduced ,

In particular, in the area of the axle receptacles 13 stiffening ribs 126 are formed, which on the edge of the axle 13 of the pivot axes pick up applied forces and distribute them in the housing. Immediately around the axle 13 around the stiffening ribs 126 are kept flat because moving in this area, the pivot lever of the pivot axes. Where possible, for example, adjacent to the end portions for separating the end portions and a central portion of the housing 10 stiffening ribs 126 are arranged, which are formed so high that they touch at the appropriate place in the first housing half shell 11 not shown here stiffening ribs, so that also here abutting surfaces 127 are formed between the two stiffening ribs. In particular, if a joining method is used for both housing half shells 11, 12, in which a connection of the inner abutment surfaces 127 is possible, for example in the aforementioned hot gas welding, so increased rigidity of the housing 10 can be achieved.

In addition 122 centering tabs 128 are arranged in the region of the screw dome, which protrude into corresponding depressions of the first housing half shell 11. If a welding method is used as the joining method, a welding of the housing half-shells 11, 12 can additionally take place at these locations, as a result of which the size of the twisting surface 11, 12 is further increased.

In the housing 10, two drive units 20 are arranged, each having an electric drive motor 21 which acts via a respective gear 22 to a spindle 24a and 24b. Optionally, a brake 23 for the spindle 24a, b is disposed adjacent to the transmission 22, in the present case in each case a loop spring brake. In the housing of the transmission 22 is also a bearing, preferably a roller bearing for the spindle 24a, b arranged.

The gear 22 are presently designed as a worm gear. A rotation of the drive shaft of the drive motor 21 is transmitted via a arranged on the drive shaft screw on a preferably helical gear of the transmission 22. Said gear is non-rotatably connected to the respective spindle 24 a, b, so that it can be rotated at reduced speed by the drive motor 21. On the transmission 22 each opposite the free end of the spindle 24a, b is a pressure slide 25 is placed, in which the spindle 24a, b retracts. The pressure slide 25 are each slidably mounted in the housing 10 in the x-direction, wherein a rotation of the pressure slide 25 is prevented by the storage.

Inside the pressure slide 25, a spindle nut is arranged non-rotatably, which cooperates with the spindle 24a, b and converts a rotation of the spindle 24a, b in a sliding movement of the corresponding slider 25. At the end of the spindle 24a, b, which is opposite to the associated gear 22, a print head 26 is placed on the pressure slide 25, against which the inserted pivot lever and the force is transmitted to this pivot lever to pivot the pivot axes.

In both drive units 20, a certain displacement for the pressure slide 25 is provided. In the Figures 3 and 4 In each case, a completely or approximately completely retracted position of the pressure slide 25 is shown, in which the latter is in each case retracted at least approximately completely to the center of the housing 10 (seen in the longitudinal direction x).

The two drive units 20 differ in the length of their spindles 24a and 24b. The length of the spindle 24a is selected so that the required displacement is achieved by the pressure slide 25 and at the same time the drive motor 21 and gear 22 are positioned as close as possible to the corresponding axle 13.

However, the second drive unit 20 has a significantly longer spindle 24b, the length of the spindle 24b is selected at a given distance of the axle 13 so that the drive motors 21 and gear 22 of both drive units 20 are arranged substantially immediately adjacent to each other in the housing 10 , In the present case, for example, only one stiffening rib 126 is arranged between the two drive motors 21. Between the gears 22 a plurality of stiffening ribs 126 are arranged in the manner of a truss composite.

The different length of the spindle 24a, b leads to a division of the space available in the housing 10, which differs advantageously from known structuring of the interior of the housing of a double drive. Apart from the end regions in which the axle receptacles 13 are arranged, in the present case the interior of the housing 10 is divided into a first installation space 15a, which lies above the spindle 24a, and a second, larger construction space 15b above the spindle 24b.

In known from the prior art double drives both drive units are formed with the shortest possible spindle whose length comparable with which the spindle 24a is. As a result, apart from the end regions, the available interior of the housing is subdivided into three construction spaces, one each above the spindles and a third installation space between the two drive motors. Accordingly, the housing space available in the housing according to the prior art in about three equal sections is divided, whereas, in contrast, he present application is divided into only two sections, one of which, the space 15 a, a comparable size as the space from the state The technique has the other (space 15b), however, is about twice as large. Even if the overall available installation space does not increase with the same length of the furniture drive, it is nevertheless less fragmented, which offers greater design freedom in the electrical and electronic components to be arranged in these installation spaces.

It is noted that in the illustrated embodiment, the eccentric arrangement of the drive motors 21 is achieved by different lengths of the spindles 34a and 34b. Equivalent to is an embodiment in which the spindles of both drive units are of equal length, but the output members, e.g. the pressure slide, are different lengths. Combinations of both versions are conceivable.

In the illustrated embodiment 15b a control board 30 is arranged in the larger of the two resulting space. The control board 30 has two areas, which in the FIG. 3 are schematically separated by a dashed line. In the in the FIG. 3 On the right-hand side of the control board 30, a power supply unit 31 is arranged, whereupon a control device 32 is located in the area shown on the left in the figure. The power supply 31 has a power connector 311, in the outside of a power cord can be inserted. The power supply 31, whose electronic components are not shown on the control board 30 for reasons of clarity, is preferably a switching power supply with a high-frequency transformer, which has a smaller footprint compared to a conventional low-frequency transformer, has less weight and is more energy efficient, especially at idle. At an output of the power supply 31 is a low voltage, preferably a DC voltage in the range of 20-30V (volts), for example nominally 24V ready, with the control device 32 and the drive motors 21 are supplied.

By the application according to the formation of the larger space 15 b, a single control board 30 can be used on the power supply 31 and control device 32 find room. The narrow elongated configuration of the control board 30 allows a secure separation of the mains voltage, which is processed in the region of the power supply 31, and the low voltage, which is supplied to the control device 32.

The control device 32 includes components for driving the drive motors 21. Such components may be electromagnetic switching devices such as relays, or semiconductor switches, for example MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) transistors or IGBT (Insulated Gate Bipolar Transistor) transistors. The switching devices either have a plurality of contact sets or are connected in the form of an H-bridge, so that the direction of rotation of the drive motors 21 can be switched.

The switching devices are controlled depending on input information of the control board 30, which are for example supplied by an external remote control, also called manual control. For this purpose, 32 externally accessible control terminals 321 are formed in the region of the control device. Furthermore, operating and / or display elements 322 are provided which may, for example, have a key function in order to be able to reset functions of the control device 32. In addition, lighting devices 323, e.g. in the form of light-emitting diodes, be arranged on the control board 30, which illuminate through corresponding openings or windows in the housing half shells 11, 12, the environment of the electromotive furniture drive. In this way, for example, a bedside lighting can be realized, which is active for a certain time after pressing a corresponding button on the remote control, so that a nighttime getting up is facilitated without a room lighting must be turned on.

Furthermore, 30 limit switches 33 are arranged on the control board, which are actuated by a push rod 34 of the pressure slides 25. The limit switches 33 prevent a movement of the pressure slide 25 outside an allowable range, for example, a mechanical stop of the pressure slide 25 on the housing 10 or on the gear 22 and the brake 23 and prevent contact between the end of the spindle 24 a, b and the Pressure plate 26 inside the pressure slide 25. The arrangement of the limit switch 33 directly on the control board 30 reduces the wiring, which would otherwise occur directly in the area of the pressure slide 25 when positioning the limit switch. The transmission of the movement or position of the pressure slide 25 on the limit switch 33 via the tow bars 34 will be described below in connection with the FIGS. 5 to 7 explained in more detail.

FIG. 5 shows an isometric oblique view of the electromotive furniture drive from a lateral oblique position. FIG. 6 also shows an isometric view of a section of the furniture drive in the region of the control board 30 in a slightly oblique view from above side view. The FIGS. 7 and 8th are detailed views of the furniture drive to the area of the control device 32 of the control board 30 with respect to the top of the control board 30 in FIG. 7 or the bottom of the control board 30 in FIG. 8 ,

In the FIGS. 5 to 8 is again like the FIGS. 3 to 4 the first housing half shell 11 (see. FIG. 1 and 2 ) away.

Each of the drive units 20 is associated with a tow bar 34a and 34b. The tow bars 34a, b are made in one piece from plastic in an injection molding process in the illustrated embodiment. In order to achieve sufficient pressure stability despite the length of the tow bars 34a, 34b and to allow a rotationally secure guide within the housing 10, the tow bars 34a, 34b are provided with longitudinally extending guide webs 341. In the housing half shells 11, 12 stiffening ribs 126 in the region of the tow bars 34a, b are formed so that they form a guide for the tow bars 34a, b, in which the tow bars 34a, 34b are guided displaceably in their longitudinal direction. The tow bars 34a, b extend substantially parallel to and above the spindles 24a, b. At each one of its ends a downwardly facing driver 342 is formed, which protrudes into the displacement of the pressure slide 25 and by transverse ribs 254 which are formed on the pressure slides 25, is moved when the pressure slide 25 just before the one or the other end of their permissible displacement.

At the opposite end of the respective tow bar 34a, b, a likewise downwardly facing spring cam 343 is formed. In the region of the spring cam 343, a return spring 35a, b is arranged on the housing 10, which consists of a w-shaped bent spring plate, which in a middle Area is fixed to the housing 10 and abuts with lateral spring arms on the side edges of the spring cam 343. In addition, a stop for the spring arms on the housing 10 is provided, which prevents each of the spring arms can indeed move outward, but not further inward than in the illustrated neutral position.

In the example in FIG. 6 well recognizable neutral position of the tow bars 34a, 34b is the spring cam 343 - depending on the design of the stop for the spring arms on the housing 10 - either not acted upon by spring force or is applied from both sides equally by the spring arms of the return spring 35a, b with spring force that in sum of the return spring 35a, b no force acting in one or the other direction of the tow bar 34a, b force is applied.

When moving the tow bar 34a, b in one or the other direction of the return spring 35a, b then each acting in the direction of the neutral position restoring force exerted by one of the two spring arms on the spring cam 343. Accordingly, the tow bar 34a, b assumes the illustrated neutral position by the return spring 35a, b, unless the catch 342 is deflected by one of the transverse ribs 254 of the pressure slide 25 in one or the other direction.

On the upper side of the tow bars 34a, b, switching cams 344 are respectively formed in the end area in which the spring cams 343 are located. The rod-shaped portion of the tow bars 34a, b and the spring cam 343 are arranged below the control board 30, whereas the switching cam 344 are located on the top of the control board 30. The tow bars 34a, b have for this purpose an upwardly pointing longitudinal web, from which the switching cam 344 protrude laterally. In the control board 30, a slot-shaped recess 324 is introduced for the passage of the longitudinal web. The slot-shaped recess 324 is similar to that in the FIG. 7 left side of the control board 30 open to the outside. When assembling the furniture drive, the tow bars 34b, 34a can be threaded into the slot-shaped recess 324 in this order. In addition to the trained in the housing 10 guides for the tow bars 34a, b and the slot-shaped recess 324 in connection with the control cam 344 supporting longitudinal webs provides a guide for the tow bars 34a, b.

On the top of the control board 30 344 limit switches 33a and b are arranged in the region of the switching cam, which are actuated by the switching cam 344. For each of the drive units 20, two limit switches 33a and 33b are provided, wherein the limit switches 33a, b arranged and the switching cam 344 are formed and arranged so that in the respective neutral position of the tow bars 34a, b none of the limit switches 33a, b is actuated , If the respective tow bar 34a, b deflected in one of the directions, in each case one of the two limit switches 33a and the two limit switches 33b is actuated.

In an alternative embodiment of the tow bar 34a, b, this is designed in several parts. In this case, the rod-shaped portion consists of a rigid rod, for example formed from a wire section. A first end of the wire is connected to a body having the previously described spring cam and the switching cams. The second end of the wire is bent angularly and forms the driver. Further alternatively, the aforementioned driver is connected to the second end of the wire.

On the control board 30, the limit switches 33a, b connected to the switching elements for driving the drive motors 21, that further driving of the respective drive motor 21 is prevented upon reaching one of the end positions, whereas a return of the drive motors 21 is possible. For this purpose, for example, each of the limit switches 33a, b be associated with a diode which is connected in parallel with the switching contacts of the limit switch 33a, b.

The not occupied by the control board 30 smaller space 15a is available for other electrical or electronic components. Optionally, for example, be arranged in the space 15a, a battery compartment in the externally accessible batteries can be inserted, which can supply the electromotive furniture drive at least temporarily with power in a power failure to allow emergency travel to a desired basic position. As an alternative to a battery compartment accessible from the outside, rechargeable batteries can also be provided in the installation space 15a for emergency travel, which then need not be accessible from outside and which are kept in a full state of charge via the control board 30 with the aid of a charge control circuit.

Furthermore, for example, receiving modules for a wireless remote control or other optional additional modules, with which the functionality of the control device 32 is supplemented, are accommodated in the installation space 15a. Additionally or alternatively, it is also possible to provide plug connectors on the control board 30 into which supplementary boards can be inserted perpendicular or parallel to the control board 30.

In FIG. 5 is also apparent that the axes of the drive motors 21 are not parallel to the pivot axes, but are tilted relative to these by about 20 to 25 degrees in the yz plane. The tilt is chosen so that a rear end of the motor housing of the drive motors 21 does not project beyond the other height of the furniture drive beyond. Nevertheless, a reduction of the width of the furniture drive in the z-direction is achieved by tilting. The motor dome 125 are in this way less than the side surface 123 over, as it would be in alignment of the motor axis along the z-direction.

In FIG. 8 a detailed drawing of the pressure slide 25 and the print head 26 is shown in isometric view. The print head 26 is shown separately from the pressure slide 25 in this figure.

The pressure slide 25 is preferably a one-piece or multi-piece plastic component, which is made of a high-strength and unbreakable plastic, for example, POM (polyoxymethylene). In the present case, the pressure slide 25 is composed of two elements, a hollow base body 251 and a Spindelmuttereinsatz 253. On the main body 251 longitudinally outwardly projecting guide ribs 252 are formed, which also serve to stiffen the base body 251.

In an end region of the main body 251 of the Spindelmuttereinsatz 253 is used. Centrally in Spindelmuttereinsatz 253 a threaded portion is formed, which serves as a spindle nut for the spindle 24a, b. The threaded portion projects into the interior of the main body 251. At the in FIG. 8 visible outside the spindle nut insert 253 protrudes plate-shaped beyond the opening in the base body 251 and is located on its end face. In this way, large forces can be transmitted from the spindle nut insert 253 to the main body 251. In an alternative embodiment of the pressure slide 25, this is in one piece. The main body 251 and the spindle nut insert 253 are then integrated in one element. The plate of the Spindelmuttereinsatz 253 also provides an over the main body 251 outwardly projecting transverse rib 254, which serves as a stop for the driver 342 of the tow bar 34a, b. Another transverse rib 254 is formed for this purpose on the opposite side of the main body 251.

The basic shape of the main body 251 varies along its longitudinal extent from a hollow cylinder on the side of the spindle nut insert 253 to a hollow cone on the opposite end of the main body 251. The transition between the two basic shapes takes place approximately in the middle of the main body 251. At the end opposite the spindle nut insert 253, the diameter of the main body 251 widens.

In the expanded opening of the main body 251 of the print head 26 is used. This has a pressure plate 261 with an outwardly facing pressure surface 262 on which abuts the pivot lever of the pivot axis of the furniture. On the opposite side of the pressure plate 261, a nozzle 264 is formed, which projects into the opening of the main body 251 of the pressure slide 25 inside. The pressure plate 261 projects outwardly beyond the connecting piece 264, so that a bearing surface 263 is formed, with which the printing head 26 rests against an end-face bearing surface 255 of the pressure slide 25. Printhead 26 and pressure slide 25 engage with each other, in the present example on the printhead 26 latching hooks 265 are formed, which are used in detent guides 256, and each engage with undercut latching projections 257.

The geometry and dimensions of the nozzle 264 are selected such that the print head 26 can be displaced laterally in the z direction relative to the pressure slide 25. When moving the printhead 26 performs no linear movement, but a pivoting movement. This is achieved by appropriate shaping of the support surface 255 of the base body 251 on the one hand and the support surface 263 of the print head 26 on the other. The support surface 255 of the pressure slide 25 is concave in the z-direction, whereas the support surface 263 of the print head 26 is convex in the z-direction. The pivotal movement allows an angle compensation, if a pivot lever is not aligned with its support surface exactly along the z-direction.

The possible angular movement is in FIG. 10 in a plan view of the end portion of the pressure slide 25 with attached printhead 26 shown in three sub-figures. In the middle part of the figure (b) the FIG. 10 is the Printhead 26 in a central position relative to the pressure slide 25. To enable movement of the print head 26, the latching hook guide 256 is slightly wider than the width of the latching hook 265 itself. In the subfigure (b), the latching hook 265 is located centrally in the latching hook guide 256 The left partial figure (a) shows the pressure plate 26, as seen from the pressure slide 25, deflected to the left and pivoted. The sub-figure (c) shows the pressure plate 26 as seen from the pressure slide 25 pivoted to the right. The freedom that the latching hook 265 has in the latching hook guide 256 is adapted to the clearance of the connecting piece 264 in the opening of the base body 251, such that a stop for the print head 26 is preferably formed by abutment of the connecting piece 254 against the wall of the base body 251 is because this attack can absorb greater forces than the latching hook 265th

As in particular in FIG. 5 can be clearly seen, the printing surface 262 of the print head 26 may not be flat. In the present case, the pressure surface 262 is slightly chamfered in the upper region in order to prevent a striking of this section of the pressure surface 262 on the pivot axis or the pivoting lever.

From the extension of the spindle 24b against the spindle 24a and the correspondingly changed arrangement of the drive motors 21 and gear 22 to each other also results in an advantage in the packaging of several of the illustrated electromotive furniture drives over the prior art. By the extension of the spindle 24b relative to the spindle 24a, the drive motors 21 are positioned close to each other, so that a single motor dome 125 can be formed on the second housing half shell 12, comprising both housings of the drive motors 21. This motor dome 125 is also not centrally located on the longitudinal side of the housing 10, but off-center. The eccentric arrangement makes it possible to position two furniture drives, each with facing each other second housing half-shells 12 within a packaging unit, with little or, depending on the geometry, no displacement of the furniture drives each other must be longitudinally.

This is in the FIG. 11 exemplified for ten arranged in pairs in a position of a packaging unit 40 furniture drives. Due to the eccentric arrangement of the motor dome 125 on the housing 10 of the furniture drives these can be arranged interleaved in pairs without being displaced significantly in the longitudinal direction against each other have to. In this way, the available storage space in the packaging unit 40 is optimally utilized. In the illustrated example, the packaging unit 40 is based on a Euro pallet 41, on which a box 42 is placed. In the carton 42 several of the illustrated layers of furniture drives can be packed one above the other. In order to be able to stack two or more packaging units 40, if necessary, 42 vertical support rollers 43 are arranged distributed inside the cardboard, which may for example consist of cardboard material like the cardboard 42.

The embodiment shown in the figures described above relates to a double drive with two drive units and two drive motors. It is noted that an according to the furniture drive can also be designed as a single drive, which has a drive unit with a motor which acts on a driven member. When using an electromotive furniture drive with only one drive motor, the output member may for example comprise a linearly movable spindle nut along a coupled thereto and rotatably driven by the drive motor (threaded) spindle. The spindle nut itself can be connected to a furniture component. Alternatively, the spindle nut can be connected to a pipe extension or extended with an extension whose free end is connected via a so-called clevis directly or indirectly with the furniture component. In an operation of the drive motor said furniture component is thereby adjusted relative to another furniture component.

LIST OF REFERENCE NUMBERS

10

casing

11

first housing half shell

111

clamp recess

112

screw

113

side surface

114

connection cavity

12

second housing half shell

121

clamp recess

122

screw boss

123

side surface

124

connection cavity

125

engine dome

126

stiffening rib

127

abutting face

128

centering bracket

13

Axle mount for swivel axis of the furniture

14

pusher

15a, b

space

20

drive unit

21

drive motor

22

transmission

23

brake

24a, b

spindle

25

pressure slide

251

body

252

guide web

253

Spindle nut use

254

Transverse rib (stop for driver)

255

convex bearing surface

256

Latch hook guide

257

catch projection

26

printhead

261

printing plate

262

print area

263

concave bearing surface

264

Support

265

latch hook

30

control boards

31

power adapter

311

mains connection

32

control device

321

control connection

322

Operating or display element

323

lighting element

324

recess

33a, b

Limit switches

34a, b

tow bar

341

guide web

342

takeaway

343

spring cam

344

switching cams

35a, b

Return spring

40

Packaging Unit

41

euro pallet

42

carton

43

supporting role

Claims (13)

1. An electromotive furniture drive for adjusting at least one furniture part of a piece of furniture having at least one drive unit (20), which comprises a drive motor (21), a gearing (22), and a spindle drive, acting on an output element displaceable along a displacement path, having a spindle (24a, 24b), and having a control board (30) for operating the drive motor (21), wherein end position switches (33a, 33b) are arranged on the control board (30), which are actuated via a control rod coupled to the output element, characterized in that the control rod is designed as a tow rod (34a, 34b), which is coupled to the output element only in end sections of the displacement path of the output element.
2. The electromotive furniture drive according to Claim 1, in which the tow rod (34a, 34b) has a driver (342), which is moved along in the end sections of the displacement path by stops on the output element in one direction or an opposing direction.
3. The electromotive furniture drive according to Claim 1 or 2, in which a restoring spring (35a, 35b) is associated with the tow rod (34a, 34b), which exerts a restoring force on the tow rod (34a, 34b) in the direction of a neutral position of the tow rod (34a, 34b) upon deflection in both directions.
4. The electromotive furniture drive according to Claim 3, in which the restoring spring (35a, 35b) is a W-shaped spring having two spring arms, which is fixed in a middle region on the housing (10).
5. The electromotive furniture drive according to Claim 4, in which a stop positioned between the spring arms is provided for the spring arms on the housing (10).
6. The electromotive furniture drive according to any one of Claims 1 to 5, in which the tow rod (34a, 34b) comprises switching cams (344) for actuating the end position switches (33a, 33b) upon deflection.
7. The electromotive furniture drive according to any one of Claims 1 to 6, in which the tow rod (34a, 34b) is guided so it is linearly displaceable by elements of the housing (10) and/or by the control board (30).
8. The electromotive furniture drive according to Claim 6 or 7, in which the control board (30) comprises a slotted recess (324), in which the tow rod (34a, 34b) is guided, wherein the switching cams (344) are arranged on one side of the control board (30) and the other sections of the tow rod (34a, 34b) are arranged on the opposite side of the control board (30).
9. The electromotive furniture drive according to any one of Claims 1 to 8, in which the drive element is a pressure slide (25) linearly displaceable between a completely retracted and a completely extended position, which deflects the tow rod (34a, 34b) upon approach to the completely retracted or the completely extended position, respectively.
10. The electromotive furniture drive according to Claim 9, in which the pressure slide (25) comprises transverse ribs (245), which form stops for the driver (342) of the tow rod (34a, 34b).
11. The electromotive furniture drive according to any one of Claims 1 to 10, which is designed as a double drive having two drive units (20), wherein both drive units (20) are arranged in succession in the longitudinal direction in a common housing (10) and wherein axis receptacles (13) for one pivot axis of the piece of furniture, on each of which an output element acts, are formed on each of opposing end sections of the housing (10) in the longitudinal direction, and wherein each drive unit is associated with a tow rod (34a, 34b) and the control board (30) comprises end position switches (33a, 33b) for both drive units (20).
12. The electromotive furniture drive according to Claim 11, in which spindles (24a, 24b) and/or the output elements of the two drive units (20) are formed having different lengths and the drive motors (21) are spaced apart by different distances from the axis receptacle (13) associated therewith for the respective pivot axis, wherein installation spaces (15a, 15b) of different sizes are formed adjacent to the spindles (24a, 24b) and wherein the control board (30) is arranged in the larger of the two installation spaces (15b).
13. The electromotive furniture drive according to Claim 12, in which a power supply unit (31) and a control device (32) for the drive motors (21) are arranged on the control board (30).

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