WO2019091997A1

WO2019091997A1 - Electromotive furniture drive with dog clutch

Info

Publication number: WO2019091997A1
Application number: PCT/EP2018/080397
Authority: WO
Inventors: Andreas Oberndörfer
Original assignee: Dewertokin Gmbh
Priority date: 2017-11-08
Filing date: 2018-11-07
Publication date: 2019-05-16

Abstract

The invention relates to an electromotive furniture drive with a drive which is designed as an electric motor and which drives a worm gear (20) via a worm (18), said gear being rotatably connected to a spindle holder (27) via a clutch which can be actuated by means of an actuation element. The spindle holder (27) receives a spindle (34) in a rotationally fixed manner, and a spindle nut (38) runs on the spindle, said spindle nut being connected to an actuation element to be moved by means of the furniture drive, such as a head or foot part of a bed or another furniture part for example. The aim of the invention is to simplify the design of such a furniture drive and provide a particularly compact furniture drive. According to the invention, this is achieved in that the clutch comprises a sliding sleeve (22), and the actuation element is designed to solely carry out a translational movement for actuating the sliding sleeve (22).

Description

Electromotive furniture drive with dog clutch

The present invention relates to a elektromo ^¬ toric furniture drive with at least one electric motor, which is at least one worm wheel in drive connection. The worm wheel is designed to drive in rotation the spindle accommodated therein via a spindle holder, on which runs a spindle nut, which is articulated to a furniture part to be adjusted, for example on a head or foot part of a hospital bed or an armchair. Between the spindle and the worm wheel, a clutch is arranged, which for the separation of the drive connection between the electric motor and spindle from a coupled drive position in which the worm wheel transmits the torque to the spindle, in a disengaged freewheeling position can be converted, in which the spindle of the worm wheel is separated and thus a freewheel of the

Spindle is possible, e.g. for the emergency adjustment of the furniture, e.g. the head or foot of a bed.

Such a furniture drive is known, for example, from DE 20 2006 009 957 U1, in which a pivotable about a pivot axis and thus acting as a rocker swivel bracket is actuated by means of a Bowden cable which opens and closes a dog clutch. This is with a coupling part against rotation with the worm wheel and with a second coupling member rotatably connected to the spindle. When pivoting the swivel bracket, the dog clutch is pushed from the drive position to the free-running position. The jaw clutch of the prior art has been well proven in practice, however, is relatively complex and subject to the flanks of the claws a steady wear, which can adversely affect the performance of the clutch over time due to the occurring game.

Based on the above-mentioned prior art and the associated disadvantages, the object of the invention is to avoid the disadvantages described above at least partially or largely and in particular to provide a compact furniture drive, which is as simple as possible.

To solve this problem, the invention proposes a single ^¬ Lich in the longitudinal direction along the longitudinal axis of the clutch sliding sliding sleeve or sliding sleeve, which forms a sliding coupling element, which is ^¬ finally by executing a translational movement of the drive in the freewheeling position can be transferred.

In an electromotive furniture drive with at least one electric motor that drives at least one worm wheel, which in turn drives a spindle and wherein zwi ^¬ tween the spindle and the worm wheel is arranged a clutch with a coupling element for separating the drive connection between the worm wheel and the spindle, proposes the Invention according to that the coupling element comprises a sliding sleeve or sliding sleeve, which is guided by means of Füh ^¬ approximately means on parts of the electromotive furniture drive. The sliding sleeve is therefore only in the longitudinal direction along the longitudinal axis on the outer surface of the screw Rads displaced, so linear or axially adjustable along the longitudinal axis of the worm wheel, whose central axis preferably with the central longitudinal axis of the furniture drive to ^¬ sammenfalls. Preferably, this central axis of the worm wheel further extends collinear to the axis of rotation of the spindle.

To stabilize this linear adjustment, embodiments include guide means, with which the sliding sleeve is guided axially movable in or on the furniture drive. Preferably, this is done by providing projections, pins or the like, which are guided longitudinally displaceable in complementarily formed guide grooves, guide grooves or the like in the respective joining partner for the engagement of the projections.

Preferably, the projections on the sliding sleeve are ^{ausgebil ¬} det, which are guided longitudinally displaceably in guide grooves on the inside of the surrounding housing. The solution according to the invention comprises that not only the

Sliding sleeve or sliding sleeve is guided directly, that is linearly guided, but instead or additionally, an actuating element of the clutch, which adjusts the sliding sleeve or sliding sleeve linearly or axially, ie disengages.

The guide or linear guide of the actuating element is preferably carried out in the surrounding housing.

The actuating element is preferably designed as a fork or shift fork, which acts on the sliding sleeve or is in operative connection therewith.

Embodiments include formed on the sliding sleeve, integrally molded projections or pins, which are guided longitudinally displaceably in the surrounding housing. The embodiment of the invention has decisive ADVANTAGES ^¬ le. A coupling with a pivoting element requires a certain space for the pivoting element, which is usually similar to a rocker pivotable about a center, is operated at one end of the rocker and engages the other end of the rocker on the actuated part of the coupling to the To open clutch. This will be for the

Swivel element requires a relatively large amount of space, although ^¬ this realized a simple operation due to the lever arm. On a swivel bracket for releasing the clutch can be completely dispensed with the invention, which greatly simplifies the construction of the clutch and this ^{insbesonde ¬} re more compact design. According to the invention, it is possible to make all the components of Möbelan ^¬ drive of plastic, which significantly reduces the price rela ^¬ hung, the manufacturing costs. An essential idea is that with the plastic parts a sufficient fit is realized in order to avoid a game and thus a deflection of the fork, which can lead to tilting of the sliding sleeve and / or the fork. Preferably, this is realized by appropriate fit at the between the joining partners, so the fork and the sliding sleeve and the fork and the housing which receives the fork. To maintain the accuracy of these fit within the framework ^¬ men, projections and seats can be provided which does not have the same areas of this subject on ^¬ wändigen fit systems, but only the immediate plant areas, ie which are in operation for engaging the respective joining partners. Preferably, this axial projections are formed on the front of the fork, which rest in the installed position on the sliding sleeve or attack on this. A further embodiment provides for the improvement of the seat and the fit accuracy that additionally or alternatively Radial projections on the radial outer side of the fork are pre ^¬ see, which in the installed position on the surrounding housing, in particular the bearing housing derived and thus ensure a ^¬ with each other and accurate positioning of the fork. To facilitate entry of the joining partners to each other at least on a joining partner in the installed position so acting against each other in installation position run-up slopes can be provided. Another measure to prevent tilting the

Fork in the operation consists in the provision of fixing pins or at least one fixing pin, with wel ^¬ cher the fork is guided or stored next to a pull rod for operating the fork in the surrounding housing. Preferably, the fixing pin extends on the outside on the back of the fork on an upper side fastening ^¬ end, particularly preferably collinear extending to a pull rod, with which the fork for disengaging actu ^¬ bar is.

The sliding sleeve or sliding sleeve is in particular out ^¬ forms as a substantially circumferentially closed, preferably hollow cylindrical body having on the inside a form-fitting structure which is complementary to a corresponding positive locking structure of the other gear parts, ie in the installed position or engaged form ^¬ conclusively the worm wheel connects to the spindle holder.

Preferably, the positive locking structure comprises a spline structure, that comprises, at the worm wheel and the spindle ^¬ holder at least one side, preferably on both sides outer spline portions on which the sliding sleeve is seated with the external spline portions inner spline structure to be longitudinally displaceable, but rotationally connected. The complementary form-fitting structure between the gear parts and the sliding sleeve can also be designed differently, for example comprising one or more splines or spline pieces. However, the configuration of the form-fitting structure as a splined shaft has the particular advantage of transmitting relatively high torques even when manufacturing the gear parts made of plastic with a compact design, to realize a good fit accuracy and to enable a long service life.

Thus, the attached ^¬ exaggerated by the drive electric motor or the worm drives the worm gear with the preferably arranged laterally next to Schneckenradkeilwelle. The sliding sleeve, which forms the coupling, sits on this worm shaft shaft in a rotationally connected and longitudinally displaceable manner. Engaged transmits the sliding sleeve, the torque of

Worm wheel on the spindle holder and the rotatably received in the ^¬ sem spindle. Disengaged, the sliding sleeve is only with the worm wheel, but not connected to the spindle holder, so that the spindle can rotate freely, ie the desired freewheel is realized, for example, for the Absen ^¬ ken of the foot or head part of an electric motor adjustable ^¬ cash bed, on which the linear drive is used.

The sliding sleeve thus moves according to the invention when engaging and disengaging purely translatory, in particular along the central longitudinal axis of the spindle or the linear gear.

The disengagement is preferably carried out against a Federrückstel ^¬ ment, so that the sliding sleeve is thus engaged in the rest position and thus transmits the torque from the worm to the spindle holder. Only when overcoming the spring force, which pushes the sliding sleeve in the engaged drive position, the freewheel is done. Preferably, the sliding sleeve in the engaged Stel ^¬ ment means acting on this sliding sleeve spring, preferably designed as a spiral spring, biased.

Preferably, moving the sliding sleeve from the engaged drive position takes place is connected to the sliding sleeve in the free-running position by a fork or shift fork, which engages around the sliding sleeve at ^¬ least one side one side or encloses, but not rotatably, so that the sliding sleeve so enclosed or Edged by the fork in this turns.

Preferably, a pull rod on the fork preferably engages a mounting position in the upper end of the fork. To Reali ^¬ tion of the freewheel, eg in an emergency only train must be exercised on the pull rod, which preferably takes place via a Bowden cable connected to the drawbar, so that the fork and the pull rod only a Translations- perform, but no tilting movement.

These also preferably in the housing, in particular in the transmission housing in holding eyes, preferably at least two

Holding eyes mounted tie rod is suitably federge ^¬ spans, which takes place in particular via a tie rod spring, which is preferably designed as a spiral spring. Preferably, the pull rod is relatively movably mounted in the housing, in particular in the inner gear housing or on the outside of the inner gear housing, but accessible from outside the Moto ^¬ rengehäuses.

The fork may comprise guiding means and is designed to be as stiff as possible in order to avoid tilting or distortion during ^loading . In the manufacture of the fork made of plastic this can be reinforced by the training

Plastic part, in particular formed as a fiber ^¬ reinforced plastic, eg with glass fibers, particularly preferably with a fiber content of 30 to 50 volume percent. Preferably, the fork has two arms or free legs, which may be exposed to a bending load and rest in the installed position on the sliding sleeve. Depending on konstrukti ^¬ ver configuration, the free legs engage in a circumferential groove of the sliding sleeve, or they are against a radially projecting beyond the outer surface of the sliding sleeve shoulder, a stop or the like, so that the fork, the sliding sleeve during execution the Trans ^¬ lationsbewegung entrains and thus disengages. In the preferred embodiment, the sliding sleeve comprises a radially over the outer surface of the sliding sleeve radially projecting shoulder or sliding sleeve shoulder, against which the shift fork abuts for disengaging. This fork can eg centrally have a force application area for the attack of the train arrangement, from which, starting from two fork arms of the fork, which engage around the sliding sleeve and engage in this. Preferably, the fork arms form with the attachment end an arcuate semicircle which surrounds the sliding sleeve in the installation position half-way or somewhat further or is seated in a receptacle of the coupling.

Preferably, the fork arms bent in an arc shape in the front view of the shift fork extend in an angle range of at least 120 degrees, preferably 180 degrees, that is to say down to the central transverse axis. The central transverse axis runs through the greatest distance between the fork arms to each other. Since the force attack of the drawbar on the fork or shift ^¬ fork is in the plane of the tie rod and the Kraftablei ^¬ tion of the shift fork takes place in a spaced-apart plane, the fork arms can ver ^¬ bend due to the lever arm. Therefore, according to the invention, guide means or stabilizing means are preferably provided which prevent tilting or tilting of the fork during disengagement. These guiding or stabilizing means are preferably formed integrally on the shift fork, but may also be designed to be attachable to this.

These guiding or stabilizing means may comprise a pin formed on the shift fork, which preferably extends opposite in extension of the tie rod and engages in the surrounding housing or is guided in this axially displaceable. Further, the pull rod is connected either rigidly or via a screw thread with the shift fork can constitute a further guiding and stabilization ^¬ agent. The guide means are preferably out ^¬ forms as sliding guides, whose sliding surfaces correspond with sliding bearing surfaces of the joint partners. In this case, the housing of the furniture drive, which preferably comprises a divisible motor housing and a housed therein, also divisible Getriebege- housing, having the sliding bearing surfaces.

Embodiments include a one-piece gearbox ^¬ begehäuse or a transmission plate designed to hold the engine and / or transmission components.

To avoid the above-described tilting or tilting of the fork or shift fork during disengagement, the guiding or stabilizing means can extend between the latter and the sliding sleeve in the longitudinal direction, preferably on the front side of the fork facing the stop of the sliding sleeve Axial projections include, which are geometrically designed to avoid tilting or tilting or at least reduce. This Axialvorsprünge are thus formed acting in the pressing or pulling direction between the fork and the sliding sleeve. Before ^¬ the axial projections are formed on the fork Trains t, rapid So forth from the arms of the shift fork and act as sliding surfaces or are formed as Gleitlagerflä ^¬ chen. The preferred embodiment comprises the formation of the axial protrusions ^¬ each at the outer free end of the fork arms, particularly ^¬ preferably on - in the front view - on the central ^¬ transverse axis extending free ends of the fork arms. A particularly preferred embodiment provides for mutually spaced pairs of axial protrusions on each fork arm of the fork. In this case, a first, outer axial projection of an axial projection pair on a fork arm, which is further formed at the outer end of the respective fork arm, preferably designed slightly larger or higher than a second, inner axial projection of a Axialvorsprungpaares, which further inward on the respective fork arm is trained. Due to the different height of the Axialvor ^¬ jumps of Axialvorsprungpaares these attack when exercising Zug on the fork when pressing for the freewheel to different degrees, therefore exercise in bending the fork arms in the longitudinal direction of different pressure and thus prevent tilting or tilting the sliding sleeve when disengaging or emergency release for the freewheel. This ensures surprisingly simple means a special ^¬ light, reliable and durable operation for the freewheel, especially in training as Kunststofftei ^¬ le. Preferably, the axial projections are formed in the front view of the shift fork above and below the central transverse axis of the overall arc-shaped switch cable.

The outer axial projection of an axial projection pair on a fork arm is preferably approximately 0.2-0.8 mm larger than the inner axial projection formed on the same fork arm an Axialvorsprungpaares.

According to the invention, the height ratios of Axi ^¬ alvorsprünge an Axialvorsprungpaares can thus be turned off on the geometric conditions of the linear transmission that they compensate for a possible deflection or bending of the shift cable due to its material properties completely. Thus, tilting and jamming of the sliding sleeve or the fork with simple and cost-effective means is effectively avoided. In particular, in the design of the gear parts made of plastic, a low rigidity of plastic can be sufficiently compensated by this surprisingly simple solution by appropriate geo ^¬ metric design, so compensated by the flexibility occurring on the plastic part who ^¬ to the desired harmonic as possible and disturbance . ^¬ free movement of the sliding sleeve in the disengagement to realisie ^¬ ren in other words, the four axial projections of two Axialvorsprungpaaren to the fork arms of the fork are preferably formed such that they compensate for the compliance of the fork arm due to its material properties so that the outer axial projection Rather abuts the joining partner as the inner axial projection, which is located closer to the point of force application of the tie rod and the traction means. As a result, the two axial projections of an axial projection pair thus act as an axial projection on each fork arm of the shift fork.

The shift fork is therefore preferably when disengaging with these four axial projections on the shoulder of the sliding sleeve.

In order to realize a particularly harmonious guidance of the shift fork even in the surrounding housing, preferred embodiments include besides or in addition to the

Axial projections radially outwardly projecting radial projections. To ensure a particularly good centering and for a harmonious development of force when disengaging the shift fork preferably has a rising in the pulling or moving direction run-on slope, so so rise in the pulling direction of the shift fork to the middle of the radial projection.

Particularly preferably bevels are formed on both sides to Mit ^¬ te of the zenith.

The linear transmission according to the invention is preferably arranged in a multipart design and thus openable housing.

Embodiments of this housing comprise an outer motor housing, in particular a two-part motor housing, which is designed to hold the one driving electric motor or drive and preferably also to be fastened to the furniture to be actuated. Preferably, a preferably also more ^¬ teilig, so openable designed gear housing for receiving the actual linear transmission is also arranged in the ^¬ sem motor housing and in which the screw driven by the preferably electromotive ausgebil ^¬ Deten drive protrudes.

Since the application of force for actuating the sliding sleeve, thus to separate or to air or to disengage the clutch connection is off center, thus, the spindle is arranged at a distance to Mittellän ^¬ gsachse, preferably Füh ^¬ agents are provided for smooth guiding of the fork In a first Embodiment, the guide means are integrally formed on the sliding sleeve and are preferably designed as pins or as projections, which continue in the direction of movement ^¬ the sliding sleeve. The non-rotatable connection of the spindle holder with the spindle is preferably carried out via the front side between the spindle and the spindle holder inserted or driven clamping ^{pins ¬} , in particular two on radially opposite Sei ^¬ th between spindle holder and spindle. A particular embodiment of the linear transmission is realized when the substantially hollow cylindrical spindle holder, the inside rotatably receiving the spindle in the outer side further comprises a support surface on which the worm wheel is seated. To further stabilize the worm wheel may include a Schneckenradhülse addition to the actual worm wheel, the preference ^¬ example is formed integrally with the worm wheel and extending in the installed position on an outer support area of the spindle holder, preferably to a rear shoulder or a bearing shoulder of the spindle holder.

Preferably, a bushing sits at a rear end on the outside of this Schneckenradhülse, which forms an outer bearing surface for a bearing that is rotatably inserted in a surrounding housing. Preferably, this bearing bush is seated with a rear end against a radially on the outer circumferential surface of the substantially hollow cylindrical spindle holder radially outwardly bearing radial flange, in which an additional paragraph for receiving the bearing bush can be provided for this purpose.

Preferably, sealing means are provided to prevent the ingress of dust and liquid into the interior of the furniture drive. In one embodiment, the pin formed as a guide and / or the projections of the sliding sleeve are formed as an extension of the actuating element.

In a further embodiment, the guide means are associated with parts of the housing of the electromotive furniture drive. Alternatively, a transmission housing or a gearbox mounting for supporting at least the worm wheel provided, wherein the guide means contact the transmission housing or the gearbox mounting.

Embodiments include sealing means on the housing to prevent the ingress of dust and liquid into the interior of the furniture drive.

In embodiments, the pins formed as a guide and / or the projections of the sliding sleeve are designed as extensions, projections, pins or the like of the actuating element.

In embodiments, the guide means are in operative connection with parts of the housing of the furniture drive. Alternatively, a transmission housing or a gearbox mounting ^¬ tion of at least the worm wheel is provided, wherein the guide means contact the gear housing or the gearbox mounting. In the following detailed description, reference is made to the accompanying drawings which form a part of this specification and in which is shown by way of illustration specific embodiments with which the invention may be practiced. In this regard, directional terminology such as "top", "bottom", "front",

"Rear", "front", "rear", etc. used in reference to the Ori ^¬ entierungen of the Figure (s). Because components of embodiments can be positioned in a number of different orientation, the correctness serves tung terminology to illustrate and is limiting in any ^¬ lei way. It is understood that other education ^¬ leadership forms utilized and structural or logical amendments ^¬ approximations can be made without departing from the scope of the present invention. the following off führliche description is not meant in a limiting sense , As used herein, the terms "connected,""connected" and "integrated" is used for loading write ^¬ both a direct and an indirect connection, a direct or indirect connection and a direct or indirect integration. In the figures, identical or similar reference numerals are lines connecting the reference numeral to the part concerned, whereas an arrow not touching any part refers to an entire unit to which it is directed not necessarily to scale: to illustrate details, certain areas may be exaggeratedly large, and the drawings may be simplistically simplified and may not include any detail that might be present in the practice, the terms "top" and "bottom" refer to on the Darst in the figures, showing:

Fig. 1 is an isometric front view of the electromotive furniture drive with closed gear and Motorge ^¬ housing;

FIG. 2 shows a longitudinal section of the electromotive furniture drive according to FIG. 1; FIG.

Figure 3 is an isometric front view of the furniture drive according to FIG 2 with removed front-side half-shell of the motor housing, but still closed Getriebege ^¬ housing and in the coupled position.

4 shows the view according to FIG. 3 in the disengaged freewheeling position; 5 shows a somewhat enlarged isometric view of the Mö ^¬ belantriebs of Figure 1 with the engine and gearbox housing in engaged drive position.

Fig. 6 is the view according to Figure 5 in the disengaged freewheel ^¬ position.

Fig. 7 is a further enlarged front view of the electromotive toric furniture drive formed as a linear gear in the engaged drive position with the engine open and Ren gear housing;

Fig. 8 is the view according to Figure 7 in a disengaged position ^¬ freewheel.

9 shows a longitudinal section of the electromotive furniture drive in engaged drive position.

FIG. 10 shows the longitudinal section according to FIG. 9 in the disengaged freewheeling position; FIG.

Figure 11 is an enlarged isometric front view of the sliding sleeve with adjacent fork;

Figure 12 is an enlarged isometric front view of the sliding sleeve itself;

Figure 13 is an enlarged isometric front view of the fork itself;

Figure 14 is an end view of the front end of the sliding ^¬ sleeve with adjacent fork; and

Figure 15 shows a preferred embodiment of the erfindungsge ^¬ MAESSEN furniture drive with removed housing cover. Figure 1 shows an isometric front view of the closed ^¬ nen, not built electromotive furniture drive, designed as a linear transmission. The furniture drive essentially comprises a two-part, closed in Figure 1 illustrated motor housing 2, in the rear end of a rear clevis 4 is received and which has a ge at the rear clevis 4 gen ^¬ opposite end a front clevis 6, via a lifting tube 8 is adjustable, which is longitudinally displaceably guided in a surrounding this guide tube 10 and is adjustable by means of the linear gear. Two Bowden cables 12, 14 engage in the front end of the Motorge ^¬ housing 2 and operate an emergency release device for disengaging the linear gear for Notverstellen provided with the linear gear cabinet.

For example, the rear clevis 4 is attached to a first cross tube of a bed frame, and the longitudinally displaceable front clevis 6 is attached to a cross tube of a foot or head part of the bed so that it can be adjusted.

The rengehäusevorderteil 2.2, consisting of a motor housing rear part 2.1 and a motorcycle, and thus formed two-part motor housing 2 accommodates which is also in two parts from a transmission housing front part 26.1 and a Getrie ^¬ begehäusehinterteil 26.2 formed transmission housing 26.

In the longitudinal section of the furniture drive according to Figure 2, the lifting tube 8 is fully retracted as in the figure 1. On

Electric motor 16 is accommodated in a rear engine housing rear part 2.1, which extends transversely to the longitudinal axis of the furniture drive extending along the lifting tube 8 and drives a worm 18 which drives a worm wheel 20 arranged transversely to the longitudinal axis of the worm 18. The worm wheel 20 includes laterally from the actual Worm wheel laterally thereof a Schneckenradkeilwelle 21, on which the sliding sleeve 22 is longitudinally displaceable, but rotatably disposed. The sliding sleeve 22 has a sliding sleeve shoulder 23 projecting radially outward from the outer cylindrical lateral surface.

The sliding sleeve 22 is seated with a rear shoulder of a hollow cylindrical lateral surface at a front shoulder of a projecting beyond an outer circumferential surface of the spindle holder 27 radial flange 27.1. The substantially hollow-cylindrical spindle holder 27 is circumferentially enclosed on the outside by the Schneckenradkeilwelle 21, which is formed as Stut ^¬ zen laterally adjacent to the worm wheel 20 and on which axially displaceable sliding sleeve 22 sits. The worm wheel 20 thus sits outside on the spindle holder 27, wherein at the front end of the actual worm wheel 20 is formed, from which the Schneckenradkeilwelle 21 extends rearwardly to a worm wheel stop of the spindle ^¬ holder 27, where in turn the sliding sleeve 22 on the outside on the rear end of the Schneckenradkeilwelle 21 axially slidably seated.

A front axial roller bearing 28 fixes the worm wheel 20 on the front side, which in turn is held on the front, by a front, designed as deep groove ball bearings ^¬ radial ball bearing 30, which together with the axial roller bearing 28 on a front end of the spindle holder 27 ^¬ th front bearing seat 27.3 with reduced Außendurchmes ^¬ ser sits and thus superimposed on this front radial ball bearing 30, the transmission in the transmission housing 26.

At the rear end in the installed position of the spindle holder 27 is mounted on a likewise designed as a deep groove ball bearing radial bearing 32 in the gear housing 26, which sits with its inner ring on a nozzle-shaped, rear bearing seat 27.2 of the spindle holder 27 and the spindle 34 is screwed by means of a screw 36.

On the spindle 34 runs a substantially hollow cylindrical spindle nut 38 whose adjustment is limited by a rear limit switch 40 and a front limit switch 42 in a known manner, the layers are adjusted as ^{needed ¬} bar. The spindle nut 38 has a front Hubrohrstutzen on which the lifting tube 8 sits to form a paragraph.

A the Schneckenradkeilwelle 21 enclosing a sliding ^¬ sleeve spring 44 formed tensioning means extends Zvi ^¬ rule the internal shoulder of the worm wheel 20 and the front of the sliding sleeve shoulder 23 of the sliding sleeve 22 and thus keeps this in the rest position in the engaged drive position in which the sliding sleeve 22, the Schneckenradkeilwelle 21 rotatably connected with a complementary to the internal geometry of the sliding sleeve spindle holder ^¬ splined connecting, which is formed on the inside of the radial flange 27.1 complementary to the Innengeomet ^¬ theory of the sliding sleeve 22nd

FIG. 4 shows the furniture drive with the engine housing front part 2.2 removed and the transmission housing 26 in the engaged drive position.

Figure 5 shows the furniture drive enlarged and also in the engaged drive position, but with removed gear housing front part 26.1.

The disengagement for the freewheel is done by pulling one of the two Bowden cables 12, 14, the front ends can end, for example, both sides of a hospital bed in handles. Seilkauschen at the rear ends of the Bowden cables 12, 14 sit in a pull rocker 46, which is externally placed on the guide tube 10 via a clamp. This pull-rocker 46 is rotatably mounted on a pin 49 which is formed at the front end of a pull rod 48 and thus extends transversely to the longitudinal direction of this drawbar 48. The pull rod 48 is connected at the end to a fork 50. This fork 50 rests with a front bearing side in a ^{¬ construction} position against the radially projecting from the outer lateral surface of the sliding sleeve 22 sliding sleeve shoulder 23, thus enclosing the outer surface of the sliding sleeve 22 in the installed position almost completely.

Axial projections 50.4, 50.5, 50.6, 50.7 are formed on the front ^¬ side of the fork arms 50.1, 50.2 of the fork 50 or formed. The fork arms 50.1, 50.2 forming a semi-circular shaped in Wesent ^¬ union, to range over a ersteckenden angle of slightly more than 180 degrees arc having at the top in the installed position the end of a drawbar eye 50.3 for the train ^¬ rod 48th

The fork 50 is biased by a fork spring 52, which extends between the fork 50 and spring holder on the outside of the gear housing 26, that shifts in the figures to the right, so that the fork 50 is not in the rest position so applied to the sliding sleeve shoulder 23. Opposite of the pull rod 48 extends coaxially to this pull rod 48, a guide pin 56 which sits in the installed position in a correspondingly formed Führungsausneh- tion on the gear housing 26 and is guided axially displaceably in this. The guide pin 56 forms one of the means for avoiding bending or Abwin ^¬ none of the fork 50 during actuation of the sliding sleeve 22nd

Further means for avoiding this bending or Abwin ^¬ none of the fork 50 are formed in the axial projections 50.4, 50.5, 50.6, 50.7 integrally formed on the front of the fork 50. The inner axial projections 50.4, 50.5 together with the outer axial projections 50.6, 50.7 on each fork arm 50.1, 50.2 each an Axialvorsprungpaar 50.4, 50.6; 50.5, 50.7. To compensate for the different lever arm from the upper point of force application of the pull rod 48 to the drawbar 50.3 further located at the outer end of a fork arm 50.1, 50.2 located outer axial projections 50.6, 50.7 in the present case about 0.2-0.8 mm higher than those further developed inside on the respective fork arm 50.1, 50.2 located inner axial projections 50.4, 50.5.

In the front view in Figure 14 is seen that the Ga ^¬ belarme 50.1, 50.2 are formed arcuate and further via a - in the front view of the fork 50 duri ^¬ Fende central transverse axis extend, which substantially by the area of the largest inside distance between the Fork arms 50.1, 50.2 extends and at their height radially on the outside of the fork arms 50.1, 50.2 radial projections 50.6, 50.7 are formed, the case when moving the Ga ^¬ bel 50 for improved engagement in the surrounding gearbox housing 26 and simplified guidance in this two-sided run-on slopes respectively. It can also be seen that the radial projections 50.8, 50.9 along the longitudinal axis of the fork arms 50.1, 50.2 between the inner radial projections 50.4, 50.5 and the outer radial projections 50.6, 50.7 are arranged to a particularly stable ^{Ausgestal ¬} tion and good leadership of the fork 50 in the To ensure transmission housing 26.

The radially outwardly protruding from the fork arms 50.1, 50.2 radial projections 50.6, 50.7 so slide with the casserole ^¬ oblique so on the inside of the surrounding housing and thereby lead the fork 50 stabilizing in this Ge ^¬ housing to avoid unwanted deflection of the fork , Finally, FIG. 15 shows a furniture drive according to the invention with the housing cover removed, in the disengaged emergency release position. Clearly visible is the worm wheel 58, on the laterally molded spline 60 axially slidably, but rotatably the sliding sleeve 62 is seated, which is disengaged via the attracted shift fork 64.

The object of the present invention is derived not only from the subject of the individual claims, son ^¬ countries from the combination of the individual claims with each other. All the materials - including the summary - disclosed details and characteristics, in particular the one shown in the drawings spatial From ^¬ formation are essential to the invention claimed, as far as they individually or in combination over the prior art are new.

Electromotive furniture drive with dog clutch

LIST OF REFERENCE NUMBERS

2 motor housing

2.1 Engine housing rear part

2.2 Motor housing front part

4 rear fork head

6 front clevis

8 lifting tube

10 guide tube

12, 14 Bowden cable

16 electric motor

18 snail

20 worm wheel

21 worm wheel spline shaft

22 sliding sleeve

23 sliding sleeve shoulder

24 rear radial bearing

26 gearbox housing

26.1 Gear housing front part

26.2 Gear housing rear part

27 spindle holder

27.1 Radial flange 27.2 rear bearing seat

27.3 front bearing seat

28 axial roller bearings

30 front radial ball bearing

32 rear radial bearing

34 spindle

36 end screw

38 spindle nut

40 rear limit switch

42 front limit switch

44 sliding sleeve spring

46 pull-tab

48 drawbar

49 cones

50 fork

50.1, 50.2 fork arm

50.3 drawbar eye

50.4 inner axial projection

50.6, 50.7 outer axial projection

50.8, 50.9 radial projection

52 fork spring

54 spring holder

56 guide pin58 worm wheel

60 splined shaft

62 sliding sleeve

64 shift fork

Claims

Electromotive furniture drive with a preferably designed as an electric motor drive which via a screw (18) drives a worm wheel (20) which is rotatably connected via an actuatable by means of an actuator Kupp ^¬ ment with a spindle holder (27), wherein the spindle holder (27) a spindle (34) rotatably receives, on which a spindle nut (38) runs, which is connected to a means of the furniture drive to be moved Be ^¬ actuating element, such as a head or foot of egg ^¬ nes bed or other furniture part,

CHARACTERIZED IN THAT the coupling comprises a sliding sleeve and a sliding sleeve (22) and that the actuating element betae ^¬ is configured to perform only a translational movement for actuating the sliding sleeve ^¬ (22).

Electromotive furniture drive according to claim 1,

THAT MENTIONED THAT the sliding sleeve

(22) is formed as a substantially circumferentially closed, preferably hollow cylindrical body, which has on the inside a form-fitting structure, the com ^¬ plementary to a corresponding form-fitting structure the worm wheel (20) and the spindle holder (27) is ^{¬ out} forms.

Electromotive furniture drive according to claim 1 or 2, characterized in that the worm wheel (20) has a Schneckenradkeilwelle (21), that the Spindelhal ^¬ ter (27) has a Spindelhalterkeilwelle, and that the sliding sleeve (22) to the Schneckenradkeilwelle (21) and the spindle ^{holder key} shaft has complementary inner geometry.

Electromotive furniture drive according to one of the preceding claims, characterized in that the actuating element has an actuatable via a tension element Ga ^¬ bel (50) or shift fork.

Electromotive furniture drive according to claim 4,

CHARACTERIZED IN THAT stabilizing means are provided between the fork (50) and the sliding sleeve (22) to prevent tilting or tilting of the fork (50) during disengagement.

Electromotive furniture drive according to claim 4 or 5, characterized in that the fork (50) has two fork arms (50.1, 50.2) designed to encompass the sliding sleeve ^¬ se (22) in the installed position, and that the fork arms (50.1, 50.2) is a substantially form arcuate geometry.

Electromotive furniture drive according to claim 5,

CHARACTERIZED BY the fact that the fork arms (50.1,

50.2) - in a front view of the fork (50) - extend over an angle of 120 to 180 degrees.

Electromotive furniture drive according to claim 5,

CHARACTERIZED THAT the fork arms (50.1, 50.2) overlap - in the front view of the fork (50) extend through the fork arms (50.1, 50.2) extending center transverse ^¬ axis addition.

9. Electromotive furniture drive according to one of the preceding claims, characterized in that the

Sliding sleeve (22) comprises a shoulder or a stop for the fork (50).

10. Electromotive furniture drive according to one of claims 5 to 9, characterized in that the Stabilisie ^¬ means between the fork (50) and the shoulder at least one, preferably a plurality of axial projections (50.4, 50.5, 50.6, 50.7) include.

11. Electromotive furniture drive according to claim 10,

THEREFORE CHARACTERIZED, that in each case two Axialvorsprünge

(50.4, 50.5, 50.6, 50.7) are formed, and that depending Weil ^¬ two axial projections on each fork arm (50.1, 50.2) of the fork (50) to form a Axialvorsprungpaares

(50.4, 50.6, 50.5, 50.7) are formed.

12. Electromotive furniture drive according to claim 11,

It should be noted that an outer axial projection (50.6, 50.7) of an axial projection pair (50.4, 50.6, 50.5, 50.7) located further at the outer end of a fork arm (50.1, 50.2) is made larger or higher than a further inward direction on the respective fork arm (50.1, 50.2) located inner axial projection (50.4, 50.5) of an Axialvorsprungpaares (50.4, 50.6, 50.5, 50.7).

13. Electromotive furniture drive according to claim 12, characterized in that the height difference between the axial projections (50.4, 50.5, 50.6, 50.7) of a Axialvorsprungpaares (50.4, 50.6, 50.5, 50.7) are adapted to the geometric conditions of the furniture drive to one to he- to compensate for waiting bending or deflection of the fork (50) when they are actuated.

Electromotive furniture drive according to one of claims 5 to 13, characterized in that the fork (50) has at least one radial projection (50.8, 50.9) with which it is guided in a surrounding housing, in particular in a transmission housing (26).

Electromotive furniture drive according to claim 14,

CHARACTERIZED IN THAT the at least one radial projection ^¬ (50.8, 50.9) has at least one counter to the To ^¬ grichtung acting when decoupling run-on slope on ^¬.

Electromotive furniture drive according to claim 14 or 15, characterized in that the at least one radial projection (50.8, 50.9) furthermore has a run-on slope acting counter to a coupling direction.

Electromotive furniture drive according to one of Claims 14 to 16, characterized in that a radial projection (50.8, 50.9) is formed on each fork arm (50.1, 50.2) of the fork (50).

Electromotive furniture drive according to one of claims 14 to 17, characterized in that the radial projection (50.8, 50.9) between the outer axial projection (50.6, 50.7) and the inner axial projection (50.4, 50.5) is formed.

Electromotive furniture drive according to one of claims 5 to 18, CHARACTERIZED IN THAT the Stabili ^¬ sierungsmittel hold at least a guide pin (56) about ^¬.

20. Electromotive furniture drive according to claim 19,

THEREFORE FEATURED THAT the guide pin (56) opposite to the tension element on the fork (50) is arranged ^{¬ assigned} .