Two-way extension rail

Abstract

The present invention relates to a two-way extension rail comprising a first rail element with a first end and a second end, and a second rail element, wherein the first rail element and the second rail element are linearly displaceable relative to each other along an extension axis between a first extension position and a second extension position. According to the invention, it is proposed that the first rail element, or a first component connected to the first rail element and immovable relative to the first rail element along the extension axis, comprises a first drive section and a second drive section, wherein the first drive section and the second drive section are spaced apart from each other along the extension axis.The second rail element, or a second component connected to the second rail element and immobile relative to the second rail element along the extension axis, has a drive unit that rotates relative to the second rail element. The first drive section and the second drive section can be coupled to and uncoupled from the drive unit, forming a positive or frictional connection.

Description

The present invention relates to a pull-out rail which has a first rail element having a first end and a second end and a second rail element, wherein the first rail element and the second rail element are linearly displaceable with respect to one another along a pull-out axis between a first pull-out position and a second pull-out position, and wherein in the first pull-out position the first end of the first rail element lies outside the second rail element in the axial direction and in the second pull-out position the second end of the first rail element lies outside the second rail element in the axial direction.Such a pull-out rail of the aforementioned type defines a so-called two-way pull-out rail. Such two-way pull-out rails are known from the prior art in various variants. Two-way pull-out rails make it possible to pull out a movable or mobile rail element relative to a stationary rail element in two mutually opposite axial first and second pull-out directions starting from a zero position (mostly the fully retracted state), wherein no stop defining the zero position and preventing a pull-out movement in one of the pull-out directions is provided. Two-way pull-out rails can be used, for example, in order to pull a drawer on two sides of the vehicle out of the latter in an emergency vehicle.Two-way pull-out rails with an electric drive require complicated drive trains because of the pull-out in two directions. Furthermore, two-way pull-out rails with three or more rail elements, which provide full or over-pull-out with synchronization of the pull-out movements of the rail elements relative to one another, are not known from the prior art.The object of the present invention is therefore to provide a two-way pull-out rail which enables in a simple manner at least one electrical drive of an at least two-part pull-out rail or a synchronization of more than two rail elements relative to one another during the pull-out movement in both pull-out directions.At least one of the aforementioned objects is achieved by a pull-out rail according to the appended independent claim. For this purpose, in the case of a pull-out rail of the type mentioned at the beginning, the first rail element or a first component which is connected to the first rail element and cannot move relative to the first rail element along the pull-out axis has a first driver section and a second driver section, wherein the first driver section and the second driver section are spaced apart from one another along the pull-out axis. According to the invention, the second rail element or a second component connected to the second rail element and immovable with respect to the second rail element along the pull-out axis has a drive unit rotating with respect to the second rail element. The first driver section and the second driver section can be coupled to the drive unit, so that a positive fit or a frictional fit is formed, and can be decoupled. In addition, the first driver section, the second driver section and the drive unit are arranged and configured such that, in the first pull-out position, the first driver section and the drive unit are uncoupled and the second driver section and the drive unit are coupled, and that, in the second pull-out position, the first driver section and the drive unit are coupled and the second driver section and the drive unit are uncoupled.The idea on which the present invention is based is to provide a two-way pull-out rail in which, depending on the pull-out direction in which the second rail element is moved relative to the first rail element, one of the two driver sections is always coupled to the drive unit, while the respective other driver section is uncoupled. Thus, a rotation of the drive unit always leads to a linear movement of the first and the second rail element relative to one another and optionally additionally of a third rail element and the second rail element relative to one another.Only in a zero position and optionally in a region around the latter are the first and the second driver section both coupled to the drive unit. The zero position is here that position of the first and the second rail element and optionally of the second and a third rail element relative to one another from which the pull-out movements begin in a first pull-out direction and in a second pull-out direction opposite the first pull-out direction. In one embodiment, the zero position is reached in the completely inserted state of the pull-out rail, in which the first and the second rail element and optionally the third rail element and the second rail element overlap at the maximum along the pull-out axis.A two-way pull-out rail is characterized in that, in the first pull-out position, the first end of the first rail element protrudes, as viewed in the axial direction, with respect to a first end of the second rail element. In other words, in the first pull-out position, the first end of the first rail element does not overlap with the second rail element as viewed in a direction perpendicular to the pull-out axis. In the second pull-out position, the second end of the first rail element protrudes beyond a second end of the second rail element. In other words, in the second pull-out position, the second end of the first rail element does not overlap with the second rail element as viewed in a direction perpendicular to the pull-out axis. This is equivalent to the formulation in independent claim 1, according to which in the first pull-out position the first end of the first rail element lies outside the second rail element in the axial direction and in the second pull-out position the second end of the first rail element lies outside the second rail element in the axial direction.If the pull-out rail with the first and the second rail element is viewed in a completely inserted state, the first end of the first rail element and the first end of the second rail element lie on the same side of the pull-out rail as viewed from a center of the pull-out rail in the axial direction. In the same way, viewed from the center of the pull-out rail, the second end of the first rail element and the second end of the second rail element lie on the same side of the pull-out rail in the axial direction.The pull-out axis defines an axis to which the opposite first and second pull-out directions of the two-way pull-out rail are parallel.In one embodiment of the invention, the first and the second rail element are mounted directly on one another in such a way that the first and the second rail element are linearly displaceable relative to one another along the pull-out axis between the first pull-out position and the second pull-out position. In this case, in one embodiment, rolling bodies are arranged between running surfaces of the first rail element and running surfaces of the second rail element. The rolling bodies, in particular bearing balls, roll between these running surfaces and reduce the friction between the first and the second rail element during the linear movement.In one embodiment of the invention, the first pull-out position and the second pull-out position are the end positions of the pull-out movements of the two rail elements relative to one another in the opposite first and second pull-out directions parallel to the pull-out axis.In one embodiment of the invention, the first rail element is the stationary rail element of the two-way pull-out rail, while the second rail element forms the mobile rail element. Such an embodiment is particularly expedient if the pull-out rail additionally has a third rail element which is linearly displaceable with respect to the second rail element.The decoupling of a driver section from the drive unit takes place by disengaging the two elements. If the drive unit comprises a drive belt or a drive chain, then the decoupling takes place when the section of the drive belt or of the drive chain with which the driver section is engaged reaches a deflection point of the drive belt or of the drive chain. If the drive unit comprises a first and a second drive wheel, the decoupling takes place when the driver section disengages from the respective drive wheel. It is understood that then typically another entrainment portion of the entrainment element engages with the drive wheel.In one variant, the first rail element comprises both the first entrainment portion and the second entrainment portion. These are spaced apart from one another in such a way that in the first pull-out position the first driver section and the drive unit are uncoupled and the second driver section and the drive unit are coupled and in the second pull-out position the first driver section and the drive unit are coupled and the second driver section and the drive unit are uncoupled.In an alternative variant, however, only the first driver section is arranged on the first rail element itself, wherein the second driver section is arranged on a first component that is immovable with respect to the first rail element along the pull-out axis. It is decisive that the second entrainment section is moved along completely synchronously with the first rail element. An example of such a variant is a pair of first and second pull-out rails according to the present invention connected via a moving element, for example via a drawer. In this case, for example, the first driver section is provided on the first rail element of the first pull-out rail and the second driver section is provided on the first rail element of the second pull-out rail.It is common to all variants and embodiments that the drive unit rotating relative to the second rail element and the first driver section or the second driver section can be coupled to one another and uncoupled from one another. In the coupled state, axial forces are transmitted from the respective driver section to the drive unit and are not transmitted in the uncoupled state.There are numerous variants for the realization of such a coupling concept. In one embodiment, a clutch is provided merely by a frictional engagement between a surface of the respective driver section and a friction belt, for example a friction belt made of rubber.In one embodiment of the invention, the drive unit comprises a drive belt or a drive chain on the second rail element, wherein two deflection elements guiding the drive belt or the drive chain are provided on the second rail element, and wherein the first and the second entrainment section are each at least one friction surface section or a positive engagement section. A friction surface section is a surface of the entrainment section of the first rail element, which is entrained by the rotating drive belt or the rotating drive chain during a corresponding rotational movement of the drive belt or the drive chain on account of the acting frictional forces. In contrast, the entrainment of the form-fitting section with the rotating drive belt or the rotating drive chain is primarily based on a form-fitting between the drive belt or the drive chain in a direction parallel to the pull-out axis.If the driver sections are realized as first and second form-fit sections and if these form-fit sections each have a plurality of teeth with the same pitch, the first and the second form-fit section must be spaced apart from one another in such a way that the distance between the two teeth of the first and the second form-fit section that are closest to one another is a multiple of the pitch of the teeth of the first and the second driver section.Examples of a drive belt based on frictional engagement include a flat belt, a V-belt and a round belt. Examples of a drive belt based on a form fit with the associated form fit section are a toothed belt and a flat belt with holes. A drive chain also uses a form fit. A driving effect between the drive belt / drive chain and the corresponding driving section due to a combination of a frictional connection and a positive connection is also conceivable.For pairings between the drive belt / drive chain and the driving section, there are the following examples, among others:flat belts with holes and entrainment section in the form of a pindriving chain and entrainment section with teeth which engage in the driving chain (a type of toothed rack)belt / drive chain in the form of a cable with spaced apart beads, the entrainment portion engaging around the beads.For a positive connection between the driver section and the drive belt / drive chain, it is expedient if the positive connection acts in both directions parallel to the pull-out axis.In one embodiment, at least one of the deflectors is a pulley rotatably mounted to the second rail member. Preferably, both deflecting elements are pulleys which are rotatable with respect to the second rail element. Such a belt pulley is, for example, a toothed belt pulley.In one embodiment of the invention, the drive belt is a double toothed belt with teeth on an outer side and with teeth on an inner side, wherein the first driver section is a first form-fit section and the second driver section is a second form-fit section, wherein the first and the second form-fit section can be brought into engagement (i.e. coupled) with the teeth on the outer side of the double toothed belt, wherein at least one of the two deflection elements is a toothed belt pulley and wherein the toothed belt pulley meshes with the teeth on the inner side of the double toothed belt.In one embodiment of the invention, the form-fitting portion is a single projection or tooth which is engageable with the teeth on the outside of the double-toothed belt. In one embodiment, at least the first form-fit section or the second form-fit section is a rack section. In a further embodiment, the first and the second form-fit sections are mutually spaced sections of a single, contiguous toothed rack.In an embodiment in which the drive unit comprises a drive belt or a drive chain, the first and second driver sections are limited along the pull-out axis to a first and a second position on the first rail element, since the drive belt extends over the second rail element along the pull-out axis. In contrast, in the embodiment described below, with a first and a second drive wheel, it is necessary for the first and the second driver section to be sections of a driver element extending in an extended manner in the axial direction along the first rail element. In this way, a portion of the driving element is always in engagement with one of the two driving wheels. Only in the zero position is the driver element engaged with both drive wheels.Therefore, in an alternative embodiment of the invention, the drive unit comprises a first drive wheel and a second drive wheel, wherein the first driver portion and the second driver portion are portions of a driver element extending in the axial direction which are spaced apart from one another, wherein the first drive wheel and the second drive wheel are rotatably mounted on the second rail element at a distance from one another along the pull-out axis, such that in the first pull-out position the driver element is in engagement with the first drive wheel and is out of engagement with the second drive wheel and in the second pull-out position the driver element is out of engagement with the second drive wheel and in engagement with the second drive wheel.In one embodiment of the invention, the first and the second drive wheel are friction wheels and the driver element with the first and the second driver section is a friction surface extended in the axial direction.In an alternative embodiment, the first drive wheel is a first gearwheel and the second drive wheel is a second gearwheel, wherein the driver element is a toothed rack which comprises the first driver section in the form of a first toothed rack section and the second driver section in the form of a second toothed rack section.In one embodiment, the first and second drive wheels are operatively coupled to one another such that they experience synchronous rotational movement during operation of the drawer rail. Synchronous rotational movement is understood to mean a simultaneous rotational movement with the same angular speed in the same rotational direction and without a temporal shift of the start and end of the rotational movement of the first and second drive wheels.In one embodiment, such a synchronous rotational movement is realized by a mechanical coupling, for example by two gears coupled via a shaft, or by a belt which connects the first drive wheel and the second drive wheel.In one embodiment of the invention, the synchronous rotational movement is provided by an electromotive drive of the first and the second drive wheel, wherein two electric motors are used for this purpose, the rotational movements of which are electronically or electrically coupled.Such an electrically driven pull-out rail comprises in one embodiment only the first and the second and no further rail element. In one embodiment, the electrically driven pull-out rail also comprises a third rail element beyond the first and the second rail element.In one embodiment, the pull-out rail comprises a third rail element having a first end and a second end, wherein the second rail element and the third rail element are linearly displaceable relative to one another along the pull-out axis between a third pull-out position and a fourth pull-out position. In such an embodiment, the second rail element forms a central rail element. In the third pull-out position, the second end of the third rail element lies outside the second rail element in the axial direction and in the fourth pull-out position, the first end of the third rail element lies outside the second rail element in the axial direction. As described above for the interaction between the first and the second rail element, the third rail element or a third component connected to the third rail element and immovable relative to the third rail element along the pull-out axis has a first driver section and a second driver section, wherein the first driver section and the second driver section are spaced apart from one another along the pull-out axis, wherein the first driver section and the second driver section of the third rail element can be coupled to the drive unit of the second rail element, such that a positive fit or a frictional fit is formed, and can be decoupled. The first driver section and the second driver section of the third rail element and the drive unit are arranged and configured such that in the fourth pull-out position the first driver section of the third rail element and the drive unit are uncoupled and the second driver section of the third rail element and the drive unit are coupled and such that in the third pull-out position the first driver section of the third rail element and the drive unit are coupled and the second driver section of the third rail element and the drive unit are uncoupled.In the zero position of the first, the second and the third rail element relative to one another, the first and the second driver section of the first rail element and the drive unit of the second rail element, as well as the first and the second driver section of the third rail element and the drive unit of the second rail element, are simultaneously coupled to one another.Such an embodiment enables a two-way pull-out rail to be realized as a full or over-pull-out.In one embodiment of the invention, the third and the second rail element are mounted directly on one another in such a way that the third and the second rail element are linearly displaceable relative to one another along the pull-out axis between the third pull-out position and the fourth pull-out position. In this case, rolling rolling rolling bodies, in particular bearing balls, are arranged between running surfaces of the third rail element and running surfaces of the second rail element between these running surfaces in one embodiment. These reduce the friction between the third and the second rail element during the linear movement.In a further embodiment, a further, non-synchronized intermediate rail element (i.e. not couplable to the drive unit) is provided in each case between the first rail element and the second rail element and optionally also between the third rail element and the second rail element. Such an extension makes it possible to remove even higher loads during an over-extraction.In one embodiment of the invention, the third pull-out position is reached exactly when the first rail element and the second rail element have the first pull-out position relative to one another and the fourth pull-out position is reached exactly when the first and the second rail element have reached the second pull-out position relative to one another.Such an embodiment with three rail elements makes it possible to realize a full or over-extraction. Such an embodiment can be used not only to drive the extension of three rail elements relative to one another by motor in two extension directions, but also to realize a manually actuated two-way extension rail with a synchronization of the movements of the first rail element with respect to the second rail element and of the second rail element with respect to the third rail element.It is understood that the configurations of the first driver section and of the second driver section of the third rail element are as diverse as was described above for the first and the second driver section of the first rail element.In one embodiment of the invention, the first entrainment portion and the second entrainment portion of the third rail element are each a friction surface portion or a form-fit portion.In one embodiment, the drive unit of the second rail element comprises a drive belt or a drive chain and two pulleys guiding the drive belt or the drive chain and rotatably mounted on the second rail element.In an alternative embodiment, in which the drive unit comprises a first and a second drive wheel, the first driver section and the second driver section of the third rail element are part of a driver element extending in the axial direction, wherein the first drive wheel and the second drive wheel of the drive unit of the second rail element are mounted on the second rail element such that they can rotate at a distance from one another along the pull-out axis in such a way that, in the third pull-out position, the driver element of the third rail element is in engagement with the second drive wheel and is disengaged from the first drive wheel and, in the fourth pull-out position, the driver element of the third rail element is disengaged from the second drive wheel and is in engagement with the first drive wheel.In one embodiment of the invention, the pull-out rail comprises, in addition to the first, the second and the third rail element, a fourth rail element having a first and a second end. The third and the fourth rail element are mounted on each other in such a way that the third and the fourth rail element are linearly displaceable relative to each other along a pull-out axis between a fifth pull-out position and a sixth pull-out position, wherein in the fifth pull-out position the second end of the fourth rail element lies outside the third rail element in the axial direction and in the sixth pull-out position the first end of the fourth rail element lies outside the third rail element in the axial direction. In order to enable synchronized pull-out movements of the fourth rail element as well in both pull-out directions with respect to the third rail element, the third rail element also has a drive unit rotating with respect to the third rail element in such an embodiment. In addition, the second rail element has a first driver section and a second driver section, wherein the first driver section and the second driver section of the second rail element are spaced apart from one another along the pull-out axis and wherein the first driver section and the second driver section of the second rail element can be coupled to the drive unit of the third rail element, such that a positive fit or a frictional fit is formed, and can be decoupled. The fourth rail element also has a first driver section and a second driver section, wherein the first driver section and the second driver section of the fourth rail element are spaced apart from one another along the pull-out axis and wherein the first driver section and the second driver section of the fourth rail element can be coupled to the drive unit of the third rail element, such that a positive fit or a frictional fit is formed, and can be decoupled. The first driver section and the second driver section of the second rail element, the first driver section and the second driver section of the fourth rail element and the drive unit of the third rail element are arranged and configured such that, in the fifth pull-out position, the first driver section of the second rail element and the drive unit of the third rail element are uncoupled and the second driver section of the second rail element and the drive unit of the third rail element are coupled and the first driver section of the fourth rail element and the drive unit of the third rail element are coupled and the second driver section of the fourth rail element and the drive unit of the third rail element are uncoupled, and that in the sixth pull-out position the first driver section of the second rail element and the drive unit of the third rail element are coupled and the second driver section of the second rail element and the drive unit of the third rail element are uncoupled, and the first driver section of the fourth rail element and the drive unit of the third rail element are uncoupled and the second driver section of the fourth rail element and the drive unit of the third rail element are coupled.In one embodiment of the invention, the axes of rotation of the drive units of the second rail element and of the third rail element are arranged next to one another in the vertical direction of the rail elements, i.e. in a vertical direction of the rail elements perpendicular to the first and second pull-out directions, such that the drive units do not interfere with one another, however, also with the entrainment sections.It is understood that the first and second entrainment portions of the second and fourth rail elements can have all alternative configurations, as have been described above for the entrainment portions of the first rail element. In addition, the drive unit of the third rail element can have all alternative configurations as have been described above for the drive unit of the second rail element.It is possible to provide further rail elements on the fourth rail element, wherein these extensions are configured as has been described above for the extension from three to four rail elements.In particular, the description of the specific possible implementations for the first and the second driver section of the third rail element and the drive unit of the second rail element shows that, with the implementation of the rotatable drive unit on the second rail element, at least the relative movement between the first rail element and the second rail element and the relative movement between the second rail element and the third rail element can be synchronized with one another or else these two synchronized relative movements can even be driven with an electromotive drive. The pull-out rail according to the invention makes it possible to realize a motor-driven two-way pull-out rail.Therefore, in one embodiment, the pull-out rail comprises an electric motor which drives the rotating drive unit during the operation of the pull-out rail. In one embodiment, this electric motor is moved together with the second rail element. In one embodiment of the invention, the electric motor drives the first and / or the second pulley and thus the drive belt or the drive chain received on the pulleys. In an alternative embodiment of the invention, the electric motor drives at least the first drive wheel or the second drive wheel.In one embodiment of the invention, the pull-out rail comprises an electric motor and a first drive drive wheel, wherein the electric motor is arranged such that the electric motor is stationary with respect to the first rail element during operation of the pull-out rail. Likewise, the axis of rotation of the drive drive wheel is stationary with respect to the first rail element in this embodiment. The electric motor is operatively connected to the first drive drive wheel in such a way that the electric motor rotationally drives the first drive drive wheel during the operation of the pull-out rail. The second rail element also has a drive entrainment element extending in the axial direction. The first drive drive wheel and the drive driver element can be coupled to one another, so that in a coupled state a rotational movement of the first drive drive wheel causes a linear movement of the second rail element.It is understood that such an embodiment, in which the second rail element is driven with such an arrangement of an electric motor and a first drive drive wheel that is stationary with respect to the first rail element, is particularly expedient if the pull-out rail also has a third rail element that is mounted so as to be movable linearly with respect to the second rail element.If the arrangement of electric motor and drive drive wheel has only the first drive drive wheel, then this is preferably arranged in a middle between the first and second ends of the first rail element. It is understood that only a partial extraction and no full or over extraction can be realized with only a single, first drive wheel. In one embodiment, the single drive drive wheel is always coupled to the drive entrainment element in all pull-out positions, so that the drive drive wheel always brings about a relative movement between the first rail element and the second rail element upon a corresponding rotation. In an alternative embodiment with likewise only a single drive drive wheel, the drive drive wheel and the drive entrainment element can also be decoupled. In this way, a part of a pull-out movement can be driven by motor and a further part of the pull-out movement can be realized in a manually driven manner.In a further embodiment, the pull-out rail has, in addition to the first drive drive wheel, a second drive drive wheel, wherein the second drive drive wheel is arranged spaced apart from the first drive drive wheel in the axial direction, wherein the first drive friction wheel and the drive driver element can be decoupled, wherein the second drive drive wheel and the drive driver element can be coupled and decoupled, such that, in a coupled state of the second drive drive wheel and of the drive driver element, a rotational movement of the second drive drive wheel brings about a linear movement of the second rail element, wherein in the first pull-out position the first drive drive wheel and the drive entrainment element are coupled to one another and the second drive drive wheel and the drive entrainment element are uncoupled, and wherein in the second pull-out position the second drive drive wheel and the drive entrainment element are coupled to one another and the first drive drive wheel and the drive entrainment element are uncoupled.It is understood that the axis of rotation of the second drive drive wheel is also stationary with respect to the first rail element.In such an embodiment, a full or over-extraction of the extraction rail can be realized by the distance of the two drive drive wheels from one another. In one embodiment, the first and the second drive drive wheel are arranged to the left and right of the center of the first rail element, preferably at the ends of the first and second rail element, in order to provide the greatest possible travel path of the two-way pull-out rail in both pull-out directions.In one embodiment of the invention, at least one of the first drive drive wheel and the second drive drive wheel is a friction wheel and the driver element is an extended friction surface extending in the axial direction of the second rail element.In an alternative embodiment, at least the first drive drive wheel is a first gearwheel or the second drive drive wheel is a second gearwheel, wherein the driver element is a toothed rack.In one embodiment of the invention, the first rail element and the second rail element each have at least one rail back and at least two limbs which extend starting from the rail back and carry running surfaces for rolling bodies. While in one variant each rail element has exactly two running surfaces for each bearing, variants are possible in which more than two running surfaces are provided on one rail element for each bearing. If a third rail element is also present in one embodiment, then this therefore likewise has at least one rail back and at least two running surfaces extending from the rail back for limbs carrying rolling bodies. In such an embodiment with a first, a second and a third rail element, the second rail element thus has a total of at least four running surfaces for rolling bodies as a central rail. The running surfaces of the first rail element and at least two running surfaces of the second rail element point towards each other, as well as optionally at least two running surfaces of the second rail element point towards the running surfaces of the third rail element. In this way, the rolling bodies can roll between at least two running surfaces of two rail elements in each case.In one embodiment, the axes of rotation of the drive unit, i.e. in particular in one embodiment the axes of rotation of the pulleys or the drive wheels, extend parallel to the rail backs of the rail elements.Further advantages, features and possible applications of the present invention will become apparent from the following description of embodiments and the associated figures. In the figures, like elements are denoted by like reference numerals. FIG. 1 is a sectional view through a first embodiment of the pull-out rail according to the invention in a completely inserted state. FIG. 2 is a sectional view of the pull-out rail from FIG. 1 in a state partially pulled out in a first pull-out direction. FIG. 3 is a sectional view of the pull-out rail of FIG. 1 in a partially pulled-out state in a second pull-out direction. FIG. 4 is an enlarged fragmentary view of FIG. 1. FIG. 5 is an enlarged fragmentary view of FIG. 2. FIG. 6 is an enlarged fragmentary view of FIG. 2. FIG. 7 is an isometric view of the pull-out rail from FIGS. 1 to 6 obliquely from below in a state in which it is partially pulled out in the first pull-out direction. FIG. 8 is a sectional view of a second embodiment of the pull-out rail according to the invention in a completely inserted state. FIG. 9 is an enlarged detail of the pull-out rail from FIG. 8. FIG. 10 is a side view of a pull-out rail according to a further embodiment in a state partially pulled out in the second pull-out direction. FIG. 11 is a partially broken away isometric view of the pull-out rail of FIG. 10 viewed obliquely from above. FIG. 12 is an isometric view of a pull-out rail according to a further embodiment with five rail elements obliquely from above.Figures 1 to 12 show a total of four different embodiments of two-way pull-out rails 4 according to the present invention. These two-way pull-out rails 4 can be pulled out in opposing first and second pull-out directions 7, 8 starting from the fully retracted states (zero position).Each of the pull-out rails 4 has a first rail element 1, a second rail element 2 and a third rail element 3.In the three embodiments of Figs. 1 to 11, the first rail member 1 is the stationary rail member, the second rail member 2 is a center rail member, and the third rail member 3 is the inner rail member which supports the moving member. The embodiment of Fig. 12 comprises a total of five rail elements, wherein the first rail element 1 is the stationary rail element and the fifth rail element 38 is the inner rail element which carries the moving component. In all embodiments, the third rail element 3 can be displaced so far with respect to the first rail element 1 that it no longer overlaps the first rail element 1 with it in a direction 6 perpendicular to the pull-out axis 5.While all four embodiments form full or over-extensions of this type, wherein the respective pull-out rail 4 comprises three rail elements 1, 2, 3 or five rail elements 1, 2, 3, 37, 38 (FIG. 12 ), embodiments are also possible in which the respective pull-out rail 4 forms only a partial extension with a motor drive in both pull-out directions. Such a variant may be sufficient with only the first rail element 1 and the second rail element 2.Along the pull-out axis 5, the second and the third rail element 2, 3 can be displaced with respect to the first rail element 1 and, starting from a completely inserted state (zero position), in mutually opposite first and second pull-out directions 7, 8. Such a fully inserted state is shown in FIGS. 1, 4, 8 and 9.The idea on which the invention is based is to combine a rotating drive unit 9 on the second rail element 2 with a first driver section 10 and a second driver section 11 on the first rail element 1 in such a way that a rotational movement of the drive unit 9 as a function of the rotational direction causes a pull-out movement of the second rail element 2 relative to the first rail element 1 in the two mutually opposite first and second pull-out directions 7, 8.In an embodiment with only the first and the second rail element 1, 2, which is not shown in the figures, it is sufficient to provide a motor drive of only the second rail element 2 with respect to the first rail element 1.All embodiments of FIGS. 1 to 12 show variants, however, in which the drive unit 9 on the second rail element 2 simultaneously also drives a withdrawal movement of the third rail element 3 in the same direction with respect to the second rail element 2. For this purpose, the third rail element 3 also has a first driver section 12 and a second driver section 13.In the embodiments of FIGS. 1 to 7 and 10 and 11, the drive unit 9 is formed by a double toothed belt 14 as drive belt, two toothed belt pulleys 15, 16 as deflection elements or pulleys and an electric motor 17. The electric motor 17 drives the second toothed belt pulley 16.The double toothed belt 14 has teeth 18 on its inner side 19, which mesh with the teeth of the toothed belt pulleys 15, 16, so that the double toothed belt 14 does not slip with respect to its toothed belt pulleys 15, 16.The double toothed belt 14 also has teeth 21 on its outer side 20. These teeth 21 on the outer side 20 of the double toothed belt 14 are in turn in engagement with a first rack section 10 and a second rack section 11 as first and second entrainment sections of the first rail element 1 in the completely inserted state of the second rail element 2 relative to the first rail element 1 (see FIGS. 1 and 4 ). The first and second rack portions 10, 11 are arranged at axially opposite first and second ends 22, 23 of the first rail member 1. The axial distance between the first and the second rack section 10, 11 is selected such that, depending on the direction of extension 7, 8, at least one of the rack sections 10, 11 is always in engagement with the outer teeth 21 of the toothed belt 14 and a rotation of the toothed belt 14 leads to a movement of extension of the rail elements 1, 2 relative to one another.The third rail element 3 also has a first rack section 12 and a second rack section 13 as first and second driver sections of the third rail element 3. These rack portions 12, 13 of the third rail element 3 are both in engagement with the teeth 21 on the outer side 20 of the double toothed belt 14 in the fully inserted state of the second rail element 2 relative to the third rail element 3 (see FIGS. 1 and 4 ). The first and the second rack sections 12, 13 of the third rail element 3 are also arranged spaced apart from one another in the axial direction 5 at the first and second ends 24, 25 of the third rail element 3. The axial distance between the first and the second rack sections 12, 13 of the third rail element 3 is selected such that, depending on the pull-out direction 7, 8, one of the rack sections 12, 13 is always in engagement with the outer teeth 21 of the toothed belt 14 and a rotation of the toothed belt 14 leads to a pull-out movement of the third rail element 3 with respect to the second rail element 2 as well.In principle, it would also be possible to configure the rack sections 10, 11 or 12, 13 of a rail element 1, 3 as a continuous rack. What is decisive for the functioning of the two-way pull-out rail 4 is only that there are rack sections spaced apart from one another in the axial direction 5.The double toothed belt 14 thus drives not only the pull-out movements of the rail elements 1, 2, 3 relative to one another, but also synchronizes them. It is directly understood that the toothed belt 14 can also be used for synchronizing the pull-out movements independently of the motorized pull-out rail 4.If, as assumed for the illustration from FIG. 2, the double toothed belt 14 rotates around on the right, the second rail element 2 and the third rail element 3 are displaced with respect to the stationary first rail element 1 in the first pull-out direction 7. After both rack sections 10, 11 and 12, 13 of the first and third rail elements 1, 3 are originally in engagement with the toothed belt 14 as shown in FIG. 1, the first rack section 12 of the third rail element 3 comes out of engagement with the toothed belt 14 shortly after the start of the pull-out movement. At the same time, the second rack section 11 of the first rail element 1 comes out of engagement with the toothed belt 14. This disengagement is also referred to as disengagement of the respective rack section 11, 12.In the fully extended state, the first end 24 of the third rail element 3 then projects in the axial direction 5 beyond the first end 33 of the second rail element 2, i.e. the first end 24 of the third rail element 3 lies outside the second rail element 2 in the axial direction. Likewise, the second end 23 of the first rail element 1 then projects in the axial direction 5 beyond the second end 34 of the second rail element 2, i.e. the second end 23 of the first rail element 1 lies outside the second rail element 2 in the axial direction.If the direction of rotation of the toothed belt 14 rotates around, then an insertion movement takes place in the opposite second extraction direction 8 from the state fully extended in the first extraction direction 7. This has the result that immediately before reaching the zero position, i.e. the completely inserted state, the first driver section 12 of the third rail element 3 couples again to the toothed belt, just like the second toothed rack section 11 of the first rail element 1.During a continued rotation of the toothed belt 14 on the left, the pull-out movement begins in the second pull-out direction 8, wherein shortly after leaving the completely inserted state (FIGS. 1 and 4 ) the first toothed rack section 10 of the first rail element 1 and the toothed belt 14 as well as the second toothed rack section 13 of the third rail element 3 and the toothed belt 14 are decoupled. The linear movements are then driven by the toothed belt 13 exclusively via the coupled second rack section 11 of the first rail element 1 and the first rack section 12 of the third rail element 3.FIG. 3 shows, in the sense of the present application, a first pull-out position of the second rail element 2 with respect to the first rail element 1 and a third pull-out position of the third rail element 3 with respect to the second rail element 2.In the embodiment of the invention according to FIGS. 1 to 7, the electric motor 17 is moved together with the second rail element 2, since it drives the toothed belt 14 via the second pulley 16. This can be seen well in the isometric view of FIG. 7.In contrast, FIGS. 10 and 11 show an alternative drive concept for causing relative movements between the second rail element 2 and the first rail element 1 and between the second rail element 2 and the third rail element 3. Instead, an electric motor 17 is provided on the stationary first rail element 1, which electric motor sets a first drive gearwheel 26 in rotation via a gear 35 and a second drive gearwheel 27 as drive drive wheels via an additional toothed belt (not shown in the figure). These drive gearwheels 26, 27 mesh through a respective aperture in the rail back of the first rail 1 (shown in FIG. 11 ) with a drive rack 28 as a drive entrainment element fixed to the second rail element 2 and, during their rotation, cause a linear movement of the second rail element 2 with respect to the first rail element 1. It is understood that the motor which is stationary with respect to the first rail element then replaces the motor which is moved with one of the other rail elements.The combination of first and second rack sections 10, 11 and 12, 13 on the first rail element 1 and the third rail element 3 and the toothed belt 14 is also the same in this embodiment as in the embodiment from FIGS. 1 to 7. Therefore, a linear movement of the second rail element 2 relative to the first rail element 1 also in the embodiment from FIGS. 10 and 11 simultaneously leads to a synchronous, linear movement of the third rail element 3 relative to the second rail element 2.FIG. 12 shows a transfer of the concept of the pull-out rail 4 from FIGS. 1 to 7 to a five-bar pull-out rail 4. The synchronization of the pull-out movements of the first, second and third rail elements 1, 2, 3 relative to one another in the first and second pull-out directions 7, 8 takes place, as in the embodiment from FIGS. 1 to 7, via a rotating drive unit 9 having a double tooth belt 14 on the second rail element 2 which is deflected by means of two toothed belt pulleys, and having a first and a second driver section 10, 11 in the form of toothed rack sections on the first rail element 1 and having a first and a second driver section 12, 13 in the form of toothed rack sections on the third rail element 3. The double tooth belt 39 of the third rail element 3 interacts with a first driver section and a second driver section 41 on the second rail element 2 and first and second driver sections (not visible in FIG. 12 ) on the fourth rail element 37. The double tooth belt 40 of the fourth rail element 37 in turn interacts with a first driver section and a second driver section 42 on the third rail element 3 and first and second driver sections (not visible in FIG. 12 ) on the fifth rail element 38.In the variant of FIG. 12, the double tooth belt 39 of the third rail element 3 is driven by an electric motor 17 which is entrained with the third rail element 3, as was described above for the embodiment of FIGS. 1 to 7. Alternatively, however, the motor could alternatively also be arranged on the second rail element 2 or the fourth rail element 37, carried along with the latter and drive the respective toothed belts 14, 40 there.FIGS. 8 and 9 illustrate an alternative concept for synchronizing the pull-out movements of the first rail element 1 with respect to the second rail element 2 on the one hand and of the third rail element 3 with respect to the second rail element 2 on the other hand. This concept for synchronizing the relative movements of the rail elements 1, 2, 3 relative to one another can also be used, as realized in the embodiments of FIGS. 8 and 9, for the motor-driven driving of the pull-out movements in both pull-out directions 7, 8.The first and second driver sections 10, 11 of the first rail element 1 and the first and second driver sections 12, 13 of the third rail element 3 are each part of a single toothed rack 29, 30 as driver element. The first and second rack sections 10, 11 of the first rail element 1 and the first and second rack sections of the third rail element are spaced apart from one another in the axial direction 5 as part of the respective rack 29, 30.In this embodiment, as in the embodiment from FIGS. 1 to 7, the electric motor 17 is moved together with the second rail element 2. The electric motor 17 synchronously drives a first and a second gearwheel 31, 32 as first and second drive wheels via a transmission 35 and a belt drive (not shown).The first and the second gearwheel 31, 32 are arranged spaced apart from one another in the axial direction 5 at the first and second ends 33, 34 of the second rail element 2. During a pull-out movement starting from the fully inserted state shown in FIGS. 8 and 9, therefore, one of the two gearwheels 31, 32 always meshes with one of the two racks 29, 30 of the first and third rail elements 1, 3. A synchronous rotational movement of the two gearwheels 31, 32 therefore enables a complete pull-out movement in both opposite pull-out directions 7, 8.For purposes of the original disclosure, it is pointed out that all features as become apparent to a person skilled in the art from the present description, the drawings and the claims, even if they have been described specifically only in connection with certain further features, can be combined both individually and in arbitrary combinations with other features or feature groups disclosed here, unless this has been explicitly excluded or technical circumstances make such combinations impossible or meaningless. The comprehensive explicit representation of all conceivable combinations of features is omitted here only for the sake of brevity and readability of the description.While the invention has been illustrated and described in detail in the drawings and the foregoing description, this illustration and description is by way of example only and is not intended to limit the scope of the invention as defined by the claims. The invention is not limited to the disclosed embodiments.Modifications of the disclosed embodiments will be apparent to those skilled in the art from the drawings, specification and appended claims. In the claims, the word "comprise" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain features are claimed in different claims does not exclude their combination. Reference numerals in the claims are not intended to limit the scope of protection.List of reference characters1 first rail element 2 second rail element 3 third rail element 4 two-way pull-out rail 5 pull-out axis 6 direction perpendicular to the pull-out axis 5 7 first pull-out direction 8 second pull-out direction 9 drive unit 10 first driver section of the first rail element 11 second driver section of the first rail element 12 first driver section of the third rail element 13 second driver section of the third rail element 14 double toothed belt 15 first toothed belt pulley 16 second toothed belt pulley 17 electric motor 18 teeth on the inner side 19 19 inner side 20 outer side 21 teeth on the outer side 20 22 first end of the first rail element 23 second end of the first rail element 24 first end of the third rail element 25 second end of the third rail element 26 first drive gear 27 second drive gear 28 drive toothed rod 29 toothed rack 30 toothed rack 31 first toothed wheel 32 second toothed wheel 33 first end of the first rail element 23 second end of the first rail element 24 first end of the third rail element 25 second end of the third rail element 26 first drive gear 27 second drive gear 28 drive toothed rack 29 toothed rack 30 toothed rack 31 first toothed wheel 32 second rail element 34 second end of second rail element 35 gear 37 fourth rail element 38 fifth rail element 39, 40 double tooth belt 41 second driver section of second rail element 42 second driver section of third rail element

Claims

Pull-out rail (4) having a first rail element (1) with a first end (22) and a second end (23) and a second rail element (2), wherein the first rail element (1) and the second rail element (2) are linearly displaceable with respect to one another along a pull-out axis (5) between a first pull-out position and a second pull-out position, and wherein in the first pull-out position the first end (22) of the first rail element (1) lies outside the second rail element (2) in the axial direction and in the second pull-out position the second end (23) of the first rail element (1) lies outside the second rail element (2) in the axial direction, characterized in that, the first rail element (1) or a first component connected to the first rail element (1) and immovable with respect to the first rail element (1) along the pull-out axis has a first driver section (10) and a second driver section (11), wherein the first driver section (10) and the second driver section (11) are spaced apart from one another along the pull-out axis (5), and the second rail element (2) or a second component connected to the second rail element (2) and immovable with respect to the second rail element (2) along the pull-out axis (5) has a drive unit (9) rotating with respect to the second rail element (2), wherein the first driver section (10) and the second driver section (11) can be coupled to the drive unit (9) so that a positive fit or a frictional fit is formed and can be decoupled, and wherein the first driver section (10), the second driver section (11) and the drive unit (9) are arranged and configured such that in the first pull-out position the first driver section (10) and the drive unit (9) are uncoupled and the second driver section (11) and the drive unit (9) are coupled and that in the second pull-out position the first driver section (10) and the drive unit (9) are coupled and the second driver section (11) and the drive unit (9) are uncoupled.Pull-out rail (4) according to the preceding claim, wherein the drive unit (9) comprises a drive belt (14) or a drive chain, wherein two deflecting elements (15, 16) guiding the drive belt (14) or the drive chain and deflecting elements are provided on the second rail element (2) or the second component, and wherein the first and the second entrainment section (10, 11) are each at least one friction surface section or a positive engagement section (10, 11).Pull-out rail (4) according to the preceding claim, wherein the drive belt is a double toothed belt (14) with teeth (21) on an outer side (20) and with teeth (18) on an inner side (19), wherein the first entrainment portion is a first form-fit portion (10) and the second entrainment portion is a second form-fit portion (11), wherein the first and the second form-fit portion (10, 11) can be brought into engagement with the teeth (21) on the outer side (20) of the double toothed belt (14), wherein at least one of the two deflection elements comprises a toothed belt pulley (15, 16) provided rotatably on the second rail element or the second component and wherein the toothed belt pulley (15, 16) meshes with the teeth (18) on the inner side (19) of the double toothed belt (14).Pull-out rail (4) according to claim 1, wherein the drive unit (9) comprises a first drive wheel (31) and a second drive wheel (32), wherein the first driver section (10) and the second driver section (11) are part of a driver element (29) extending in the axial direction, wherein the first drive wheel (31) and the second drive wheel (32) are rotatably mounted on the second rail element (2) at a distance from one another along the pull-out axis (5) such that in the first pull-out position the driver element (29) is in engagement with the first drive wheel (31) and out of engagement with the second drive wheel (32) and that in the second pull-out position the driver element (29) is out of engagement with the first drive wheel (31) and in engagement with the second drive wheel (32).Pull-out rail (4) according to the preceding claim, wherein the first drive wheel is a first gearwheel (31) and the second drive wheel is a second gearwheel (32), and wherein the driver element is a toothed rack (29).Pull-out rail (4) according to Claim 4 or 5, wherein the first drive wheel (31) and the second drive wheel (32) are operatively coupled to one another in such a way that they experience a synchronous rotational movement during operation of the pull-out rail (4).Pull-out rail (4) according to one of the preceding claims, wherein the pull-out rail (4) comprises a third rail element (3) having a first end (24) and a second end (25), wherein the second rail element (2) and the third rail element (3) are linearly displaceable relative to one another along the pull-out axis (5) between a third pull-out position and a fourth pull-out position, wherein in the third pull-out position the second end (25) of the third rail element (3) lies outside the second rail element (2) in the axial direction of the pull-out axis (5) and in the fourth pull-out position the first end (24) of the third rail element (3) lies outside the second rail element (2) in the axial direction, wherein the third rail element (3) or a third component connected to the third rail element (3) and immovable relative to the third rail element (3) along the pull-out axis (5) has a first entrainment portion (12) and a second entrainment portion (13), wherein the first entrainment portion (12) and the second entrainment portion (13) are spaced apart from one another along the pull-out axis (5), wherein the first entrainment portion (12) and the second entrainment portion (13) of the third rail element (3) can be coupled to the drive unit (9) such that a positive fit or a frictional fit is formed, and can be decoupled, wherein the first entrainment portion (12) and the second entrainment portion (13) of the third rail element (3) and the drive unit (9) are arranged and configured in such a way, in the fourth pull-out position, the first driver section (12) of the third rail element (13) and the drive unit (9) are uncoupled and the second driver section (13) of the third rail element (3) and the drive unit (9) are coupled, and in the third pull-out position, the first driver section (12) of the third rail element (3) and the drive unit (9) are coupled and the second driver section (13) of the third rail element (3) and the drive unit (9) are uncoupled.Pull-out rail (4) according to the preceding claim as far as dependent on claim 2, wherein the first entrainment portion (12) and the second entrainment portion (13) of the third rail element (3) are each a friction surface portion or a positive-locking portion (12, 13).Pull-out rail (4) according to claim 7 or 8 as far as dependent on claim 4, wherein the first driver section (12) and the second driver section (13) of the third rail element (4) are part of a driver element (30) extending in the axial direction, wherein the first drive wheel (31) and the second drive wheel (32) are mounted on the second rail element (2) such that they can rotate at a distance from one another along the pull-out axis (5) in such a way that, in the third pull-out position, the driver element (30) of the third rail element (3) is in engagement with the second drive wheel (32) and is out of engagement with the first drive wheel (31), and that, in the fourth pull-out position, the driver element (30) of the third rail element (3) is out of engagement with the second drive wheel (32) and is in engagement with the first drive wheel (31).Pull-out rail (4) according to one of the preceding claims, wherein the pull-out rail (4) has an electric motor (17), wherein the electric motor (17) is arranged on the second rail element (2) in such a way that the electric motor (17) is moved together with the second rail element (2) during the operation of the pull-out rail (4), and wherein the electric motor (17) is operatively connected to the drive unit (9) in such a way that the electric motor (17) drives the drive unit (9) during the operation of the pull-out rail (4).Pull-out rail (4) according to one of Claims 1 to 9, wherein the pull-out rail (4) has an electric motor (17) and a first drive drive wheel (26), wherein the electric motor (17) is arranged in such a way that, in the operation of the pull-out rail (4), the electric motor (17) is stationary with respect to the first rail element (1), wherein the electric motor (17) is operatively connected to the first drive drive wheel (26) in such a way that, in the operation of the pull-out rail (4), the electric motor (17) rotationally drives the first drive drive wheel (26), wherein the second rail element (2) has a drive driver element (28) which extends in the axial direction, wherein the first drive drive wheel (26) and the drive driver element (28) can be coupled to one another, such that, in a coupled state of the first drive drive wheel (26) and of the drive driver element (28), a rotational movement of the first drive drive wheel (26) causes a linear movement of the second rail element (2).Pull-out rail (4) according to the preceding claim, wherein the pull-out rail (4) has a second drive wheel (27), wherein the second drive wheel (27) is arranged spaced apart from the first drive wheel (26) in the axial direction, wherein the first drive wheel (26) and the drive driver element (28) can be decoupled, wherein the second drive wheel (27) and the drive driver element (28) can be coupled and decoupled, such that, in a coupled state of the second drive wheel (27) and of the drive driver element (28), a rotational movement of the second drive wheel (27) causes a linear movement of the second rail element (2), wherein in the first pull-out position the first drive drive wheel (26) and the drive entrainment element (28) are coupled to one another and the second drive drive wheel (27) and the drive entrainment element (28) are uncoupled, and wherein in the second pull-out position the second drive drive wheel (27) and the drive entrainment element (28) are coupled to one another and the first drive drive wheel (26) and the drive entrainment element (28) are uncoupled.Pull-out rail (4) according to one of the preceding claims as far as dependent on claim 7, wherein the pull-out rail (4) comprises a fourth rail element (37) having a first and a second end, wherein the third rail element (3) and the fourth rail element (27) are linearly displaceable with respect to one another along the pull-out axis (5) between a fifth pull-out position and a sixth pull-out position, wherein in the fifth pull-out position the second end of the fourth rail element (37) lies outside the third rail element () in the axial direction, wherein in the sixth pull-out position the first end of the fourth rail element (36) lies outside the third rail element (3) in the axial direction, wherein the third rail element (3) has a drive unit (9) rotating with respect to the third rail element (3), wherein the second rail element (2) has a first entrainment portion and a second entrainment portion (41), wherein the first driver portion and the second driver portion (41) of the second rail element (2) are spaced apart from one another along the pull-out axis (5), wherein the first driver portion and the second driver portion (41) of the second rail element (2) can be coupled to the drive unit (9) of the third rail element (3) such that a positive fit or a frictional fit is formed, and can be decoupled, wherein the fourth rail element (37) has a first driver portion and a second driver portion (42), wherein the first driver portion and the second driver portion (42) of the fourth rail element (37) are spaced apart from one another along the pull-out axis (5), wherein the first driver portion and the second driver portion (42) of the fourth rail element (37) can be coupled to the drive unit (9) of the third rail element (3) such that a positive fit or a frictional fit is formed, and being able to be decoupled, wherein the first driver section and the second driver section (41) of the second rail element (2), the first driver section and the second driver section (42) of the fourth rail element (37) and the drive unit (9) of the third rail element (3) are arranged and configured such that, in the fifth pull-out position, the first driver section of the second rail element (2) and the drive unit (9) of the third rail element (3) are decoupled and the second driver section (41) of the second rail element (2) and the drive unit (9) of the third rail element (3) are coupled and the first driver section of the fourth rail element (37) and the drive unit (9) of the third rail element (3) are coupled and the second driver section (42) of the fourth rail element (37) and the drive unit (9) of the third rail element (3) are decoupled, and that in the sixth pull-out position the first driver section of the second rail element (2) and the drive unit (9) of the third rail element (3) are coupled and the second driver section (41) of the second rail element (2) and the drive unit (9) of the third rail element (3) are uncoupled, and the first driver section of the fourth rail element (37) and the drive unit (9) of the third rail element (3) are uncoupled and the second driver section (41) of the fourth rail element (37) and the drive unit (9) of the third rail element (3) are coupled.

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