Drive device for a movable furniture part

A drive device for a movable furniture part includes a lockable ejection device for ejecting the movable furniture part out of a closed position into an open position. The ejection device can be unlocked by pushing the movable furniture part over into an pushed-over position located behind the closed position in the closing direction. A blocking element is provided, and the blocking element has a first position in which the movable furniture part can be stopped when reaching the closed position, so that the blocking element prevents a further movement of the movable furniture part in the closing direction. The locking element also has a second position in which the path into the pushed-over position for the movable furniture part is enabled.

BACKGROUND OF THE INVENTION

The invention concerns a drive device for a moveable furniture part comprising a housing and an ejection device moveable relative to the housing and lockable to the housing for ejecting the moveable furniture part out of a closed position into an open position. The ejection device is unlockable by over-pressing the moveable furniture part into an over-pressed position which is behind the closed position in the closing direction. The invention also concerns an article of furniture having such a drive device, and a method of moving a moveable furniture part comprising a lockable ejection device for ejecting the moveable furniture part out of a closed position into an open position. The ejection device is unlocked by over-pressing the moveable furniture part into an over-pressed position which in the closing direction is behind the closed position.

Drive devices have already been known for many years in the furniture fitment industry, which by virtue of pressing against a moveable furniture part (drawer) unlock it from the furniture carcass and then open or eject it. Such drive devices have a so-called touch-latch mechanism. In those mechanisms, the movement for closing the drawer from the open position and the movement for opening the drawer from the closed position occur in the same direction (closing direction). In the case of normal soft closure (by hand or by a retraction device), the drawer or the moveable furniture part is held in the closed position by the lockable ejection device. If, however, the drawer is excessively vigorously pushed closed, the ejection device cannot lock at all or it is immediately moved into the over-pressed position again due to the high closing speed and as a result is unlocked, whereby secure closure of the moveable furniture part (in the event of an excessively vigorously closing movement) is not guaranteed.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to overcome that disadvantage. In particular, the invention seeks to ensure that, in the event of excessively firm or excessively fast manual closing, immediate re-opening or ejection is prevented.

For a drive device of the present invention, that object is achieved by a blocking element which has a first position in which the moveable furniture part can be stopped when reaching the closed position, wherein the blocking element prevents a further movement of the moveable furniture part in the closing direction. The blocking element also has a second position in which the path into the over-pressed position for the moveable furniture part is enabled. Thus, the present invention provides protection from excessive pressing implementation, such protection preventing immediate re-opening in the event of excessively fast closure and guaranteeing reliable attainment of the closed position.

When reaching the closed position, the blocking element is in the first position (with a high closing force) or in the second closed position (with a low closing force), depending on the closing force acting on the drive device. It is preferable however, that when reaching the closed position, the position of the blocking element (this can also be referred to as a temporarily removeable abutment) is dependent on the closing speed of the moveable furniture part. In other words, as soon as the closing speed exceeds an adjustable or fixed threshold value (preferably 20 mm/second), the blocking element guarantees that the drawer is stopped in the closed position and does not move immediately into the over-pressed position. The blocking element thus acts in a speed-controlled fashion.

Also, the blocking element can be adapted to be time-controlled, for example by way of a rotational damper. In other words, in each closing situation, it is guaranteed that the moveable furniture part is held exactly in the closed position for example between one second and three seconds. It is only thereafter, by cessation of the damping action of the rotational damper, that a further movement in the closing direction (into the over-pressed position) is permitted. The blocking element can also be pressure-controlled and/or force-controlled.

The possibility should not be excluded that the blocking element is moved based on a speed sensor which measures the closing speed of the moveable furniture part into the first position (in the event of a speed above a threshold value) and into the second position (at a low closing speed). A purely mechanical solution is preferred, however, in which the blocking element is arranged displaceably in a guide track provided in a housing of the drive device and having a closed position abutment and an evasion portion. In the first position, the blocking element bears against the closed position abutment, and in the second position, the blocking element is moveable into the evasion portion. The movement into the second position can preferably be effected by pivotal movement of the blocking element transversely relative to the closing direction. A force storage member, preferably a torsion spring, is preferably provided for triggering the movement of that blocking element.

In general, ejection devices and also automatic retraction devices which guarantee reliable soft closure of the moveable furniture part are used nowadays in the furniture fitment industry. Preferably, such a retraction device retracts the moveable furniture part at a speed of about 20 mm/second.

In a particularly preferred embodiment of the present invention, in the first position the blocking element is clamped between an entrainment element of the retraction device and the closed position abutment. This means that the blocking element is always moved depending on the retraction device, in which case in the event of the moveable furniture part being excessively vigorously pushed shut by hand, the retraction device itself no longer acts but the blocking element in its first position guarantees that the moveable furniture part is reliably stopped in the closed position.

In addition, a damping device is provided for damping the retraction movement triggered by the retraction device. The damping device has a piston and a cylinder, and the piston bears against the housing of the drive device and the cylinder is moveable relative to the housing of the drive device by the entrainment means of the retraction device, preferably by way of a coupling element on the cylinder. Preferably, the blocking element is arranged on the damping device, preferably the cylinder thereof, and the blocking element is moveable relative to the cylinder of the damping device, preferably being rotatable about the cylinder.

The closing speed-dependent control is achieved in that at a closing speed of below 20 mm/second the blocking element is moveable into the evasion portion—and thus into the second position—by the force storage member before reaching the closed position abutment. This means that the force storage member can deliver its force acting on the blocking element, in good time, insofar as the blocking element no longer hits against the closed position abutment. However, the blocking element can also be moved into the evasion portion after (blockingly) reaching the closed position and after cessation of the closing or retraction force.

For the ejection device, the ejection device preferably has an ejection slider displaceable relative to the housing and an ejection force storage member fixed on the one hand to the housing and on the other hand to the ejection slider. Locking of the ejection device can be effected by per se known means. Preferably, the ejection slider is lockable in the closed position in a sliding guide track which is provided in the housing and which preferably has a cardioid-shaped portion with a latching recess, by way of a locking pin separate from the blocking element. The locking pin prevents a movement of the moveable furniture part in the opening direction. In that case, the locking pin in corresponding relationship with the latching recess only prevents the movement of the moveable furniture part in the opening direction. The movement in the closing direction is not prevented by the locking pin and must even be absolutely possible for the unlocking action. The movement into the over-pressed position can be blocked only by the blocking element in its first position. Otherwise, it is always to be possible to reach the over-pressed position.

Protection is also claimed for an article of furniture having a drive device according to the invention. The drive device can be associated with the furniture carcass and can act on an entrainment element arranged on the moveable furniture part. It is preferable, however, that the housing of the drive device is disposed on the moveable furniture part, preferably on a drawer rail of an extension guide, and the entrainment element is arranged on the furniture carcass, preferably at the carcass rail thereof. That permits clever and space-saving placement of the drive device.

For a method of the present invention, the object is attained in that the moveable furniture part is stopped when reaching the closed position by a blocking element which is in a first position. A further movement in the closing direction is prevented by the blocking element, and when the blocking element is in a second position, the path into the over-pressed position for the moveable furniture part is enabled.

In that case, the closing speed-controlled movement of the blocking element can be implemented in such a way that when reaching the closed position the blocking element is in the first position only when the closing speed of the moveable furniture part just before reaching the closed position corresponds to the retraction speed triggered by a retraction device or is above a maximum retraction speed triggerable by a retraction device. In that respect, “just” before reaching the closed position refers to a region of about 3 cm before the closed position. This means that the blocking element in its first position stops the moveable furniture part in the closed position both upon retraction by the retraction device and also upon the moveable furniture part being excessively quickly slammed shut. In the event of a slower closing movement than by the retraction device (for example by active manual retardation of the retraction device) or after cessation of the closing force triggered by the retraction device or by hand, the blocking element passes into its second position and permits over-pressing of the moveable furniture part to a position behind the closed position.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1diagrammatically shows an article of furniture17comprising a furniture carcass13and two moveable furniture parts2. The upper moveable furniture part2shown, with a front panel20and a drawer box (body)21, is in an open position OS while the lower moveable furniture part2is in a closed position SS. The moveable furniture parts2are respectively mounted displaceably on the furniture carcass3by a drawer rail18and a carcass rail22which together form an extension guide19. A respective drive device1is arranged via a housing3(not shown) in the region of the drawer rail18. On the one hand, that drive device1has an ejection device5comprising an ejection slider6and an ejection force storage member7, and on the other hand a retraction device8comprising a retraction slider9and a retraction force storage member10. The drive device1also has an entrainment element4arranged on the carcass rail22or on the furniture carcass13. When the moveable furniture part2is moved out of the open position OS in the closing direction SR, the entrainment element4firstly comes into contact with the retraction slider9. As that retraction slider9is locked to the ejection slider6, the force storage member7(in this view a compression spring) is stressed upon closing of the moveable furniture part2as the ejection slider6moves relative to the drawer rail18. When the retraction portion is reached, the ejection force storage member7is completely stressed and the retraction slider is unlocked whereby the retraction force storage member10(in this view a tension spring) is relieved of stress or contracts and thereby retracts the moveable furniture part2by way of the entrainment element4into the closed position SS (see the lower drawer).

FIG. 2shows a moveable furniture part2with a front panel20and a drawer box (body)21and with a drive device1mounted to the drawer rail18, together with a synchronization element23.

FIG. 3, of the drawer box (body)21, also shows the side wall (drawer frame member), whereby there is free view of the container rail24. The bottom (not shown here) of the drawer box21is fixed to the drawer rail18by that container rail24. A central rail can also be provided between the drawer rail18and the carcass rail22.

FIG. 4shows the drawer rail18with drive device1mounted thereto, together with a part of the synchronization element23.

FIG. 5shows that the synchronization element23is held by a holder25mounted to the housing3of the drive device1. That holder25is moveable relative to the housing3upon depth adjustment for adjusting the depth of the closed position of the moveable furniture part2in the furniture carcass13.

FIG. 6shows a view of the drive device1from behind, showing that the housing3comprises on the one hand the base plate27and on the other hand the cover plate28. This Figure also shows the holding bracket26for the entrainment element4. The holding bracket26connects the entrainment element4to the carcass rail22.

FIG. 7shows the drive device1without the cover plate28, thereby giving a free view into the interior of the drive device1. Shown therein is the housing central plate31which forms a further part of the housing3and which is adjustable relative to the two outer housing parts27and28by the depth adjusting wheel34. Also arranged on that housing central plate31is the damping device16which includes a damping cylinder29and a damping piston30, wherein the damping piston30bears against the retraction slider9(not shown here) at least in the retraction movement. Also shown in the region of the housing central plate31is the overload spring35for overload protection, which guarantees that the moveable furniture part2can also be moved out of the closed position SS by pulling without suffering damage. The ejection force storage member7is held by the spring base32to the housing3and on the other hand by the spring base33to the ejection slider6. The module77for affording protection from excessive pressing implementation is not shown inFIG. 7—like also inFIGS. 9 and 10.

FIG. 8(without base plate27but in return with the cover plate28) in contrast also shows the retraction force storage member10which is held by the spring base36on the one hand to the ejection slider6and by the spring base37on the other hand to the retraction slider9.

FIG. 9shows once again the essential components of the housing3, namely the base plate27, the cover plate28and the housing central plate31which is only displaceable therein for depth adjustment. In addition, shown on the housing central plate31are the studs41, by way of which the displacement movement is made possible by rotation of the depth adjusting wheel34. The overload spring35and the overload rod42as well as the damping device16(with the coupling element76displaceable by the entrainment means75) are arranged on the housing central plate31. The ejection slider6is mounted displaceably between the housing central plate31and the base plate27, and the locking lever44is mounted rotatably to the ejection slider6and engages by way of its locking pin43into the sliding guide track12which is provided in the housing central plate31and which has a cardioid-shaped portion. The retraction slider9is once again mounted displaceably along the ejection slider6, and the retraction slider9includes the slider base39, the locking element15, the catch lever38, and the contact portion40. That contact portion is formed from a relatively soft plastic whereby the entrainment element4bearing against it in that region experiences a certain damping action in particular upon rapid closing movement, and the retraction slider9is less worn away and subjected to wear and tear.

In comparison withFIG. 9,FIG. 10additionally shows the components for synchronizing drive devices1arranged at both sides of the moveable furniture part2. In this case, shown on the extension slider6are synchronization teeth46to which the synchronization gear45corresponds. The synchronization element23engages into that synchronization gear25and, in the case of drive devices1arranged at both sides, guarantees synchronous triggering of unlocking and synchronous stressing of the ejection force storage member7.

FIG. 11is a view without base plate27, showing the cover cap28and the housing central plate31with sliding guide track12and latching recess11.FIG. 11also shows the ejection slider6, the ejection force storage member7, the retraction force storage member10and the retraction slider9together with the slider base39and the catch lever38as well as the entrainment element4. InFIG. 11, the moveable furniture part is in the open position OS. The retraction slider9is in the locking position VE. That locking position VE is defined by the locking element15being locked by an inclined locking portion in the ejection slider6and being unable to pivot about the pivot axis. That is made possible by the fact that the retraction force storage member10pulls lightly on the slider base36and as a result the locking element15cannot move upwardly. Alternatively, the locking element15cannot be allowed to unlock by the provision of a control track in the housing3.

InFIG. 12, the closing movement of the moveable furniture part2in the closing direction SR begins, the entrainment element4bearing against the retraction slider9, preferably at the contact portion40thereof. By virtue of that movement in the closing direction SR, the ejection slider6is displaced towards the left relative to the housing3whereby the ejection force storage member7in the form of a tension spring is stressed. At the same time, the catch lever38is deflected by the inclined deflection portion on the housing3and “catches” the entrainment element4in the retraction slider9.

The ejection force storage member7is completely stressed inFIG. 13. In addition, the control pin43has moved beyond the latching recess11of the sliding guide track12by about 3.5 mm. At the same time in that position, the locking element15is unlocked by the retraction portion E of the control track14in the housing3, that is shown inFIG. 14. As a result, the retraction slider9is no longer in the locking position VE.

That unlocking action provides that the retraction slider9is no longer held on the ejection slider6and the retraction device8moves the moveable furniture part2out of the open position OS shown inFIG. 13into the closed position SS inFIG. 14. That retraction is ensured by the catch lever38and its transmission of force to the entrainment element4. In that retraction movement, the retraction force storage member10in the form of a tension spring is relieved of stress. Because pressure is no longer exerted on the moveable furniture part2in the closing direction SR, the locking pin43also moves into the latching recess11whereby the locking position VA of the ejection slider6and thus the moveable furniture part2is reached.

FIG. 15shows the drive device1with the base plate27and the cover cap28of the housing3. The cover plate28is removed inFIG. 16and there is a free view on to the damping device16and the housing central plate31.

FIG. 17shows that the protective module77for protection from excessive pressing implementation and which surrounds the damping piston30is additionally arranged on the damping cylinder29.FIG. 18shows a rear view corresponding toFIG. 17of the housing central plate31. In that case, both the coupling element76arranged on the damping cylinder29or fixedly connected thereto and also the blocking element70engage into the guide track71in the housing central plate31. In addition, that guide track71has the closed position abutment72and the evasion portion73.

FIG. 19shows an exploded view of the essential components of the protective module77. In that case, the blocking element70is fitted on the base element80and is acted upon with force by the force storage member74(torsion spring) in the clockwise direction. The blocking element70is held to the base element80by the front cap79and can only rotate about same. An abutment damping element78is disposed between the blocking element70and the front cap79. The element78is preferably in the form of a felt ring.FIG. 20shows the module77in the assembled condition.

FIGS. 21 and 21ashow a section through the module77installed in the drive device1. In this arrangement, the extension of the blocking element70engages through the guide track71provided in the housing central plate31. It is also possible to see the holding bracket26for the entrainment element4and the ejection slider6. The slider base39of the retraction device8, which is displaceable in the ejection slider6by way of the retraction force storage member10, is also shown. A closing force is applied to the blocking element70by that retraction device8. The ejection force storage member7exerts force on the ejection slider6in the opening direction OR.

FIGS. 22 and 22ashow in detail how force is exerted on the damping device16and the module77in the closing direction SR by the retraction device8. More specifically, for that purpose the locking element15of the retraction device8or of the retraction slider9has an entrainment element75which upon retraction bears against the coupling element76and retracts it or entrains it together with the damping cylinder29in the closing direction SR against the force of the damping device16. The protection module77arranged on the damping cylinder29together with the blocking element70is also entrained thereby and moved relative to the damping piston30bearing against the housing central plate31.

That entrainment element75is no longer shown inFIGS. 23 and 23a, but it is possible to see where the coupling element76and the blocking element70are disposed before the beginning of the retraction movement, in the guide track71.

Due to excessively fast manual closure of the moveable furniture part2, the damping cylinder29is moved so fast in the closing direction SR by the entrainment element75whereby the blocking element70cannot move into the evasion area73and is thus clamped between the entrainment element75or the coupling element76and the closed position abutment72(seeFIGS. 24, 24a,25and25a). In that first position BL of the blocking element70, the moveable furniture part2cannot be pushed in to such a degree that the locking pin43is unlocked from the latching recess11of the cardioid curve.

In contrast,FIGS. 26, 26a,27and27ashow that, in the case of a slower closing movement or a closing movement triggered by the retraction device8, the blocking element70can already pivot or move into the evasion area73in the region of the inclined evasion portion81by virtue of the force actuation by the force storage member74, thereby reaching the second position FR of the blocking element70. In the specified Figures, the moveable furniture part2is in the closed position.

If now as shown inFIGS. 28 and 28apressure is applied to the moveable furniture part2out of that closed position SS in the closing direction SR, then the coupling element76and therewith the entire ejection slider6can move along the triggering travel AW into the over-pressed position ÜS. As the blocking element70is arranged in or has been deflected into the evasion area73, it can no longer prevent the triggering movement but enables the travel into the over-pressed position ÜS. In that way, the ejection force storage member7can deploy its action and by way of the ejection slider6moves the moveable furniture part2in the opening direction OR. As a further consequence, the retraction slider9is also stressed again. In that case, the entrainment element75also moves away from the coupling element76of the damping cylinder29again whereby the damping piston30can move out of the damping cylinder29again. In that movement, the coupling element76and the blocking element70are also moved in the opening direction OR along the guide track71. By virtue of the movement of the blocking element70along the inclined evasion portion81, the blocking element70is rotated in the counter-clockwise direction and thereby the force storage member74is stressed. After that, the blocking element70moves back into the starting position shown inFIG. 23a.

FinallyFIGS. 29 through 31show once again diagrammatically the protection from excessive pressing implementation according to the invention, in which respect as shown inFIG. 29the moveable furniture part2bears (for example) directly against the blocking element70. That blocking element70is acted upon by force of the force storage member74transversely relative to the closing direction SR and is guided in the guide track71.

If, as shown inFIG. 30, the moveable furniture part2is closed too quickly, the force of the force storage member74cannot be sufficiently deployed and the blocking element70is clamped between the moveable furniture part2and the closed position abutment72. That provides the first position BL, and the moveable furniture part2is reliably stopped in the closed position SS. As soon as the force acting on the moveable furniture part2(momentum from closing or being forced held shut) ceases, the friction between the blocking element70and the closed position abutment72and/or the furniture part2(or the coupling element76) also ceases, and so the force storage member74can move the blocking element70into the evasion portion73. This therefore also guarantees that the blocking element70acts in force-controlled fashion. This means that, after excessively fast closure of the moveable furniture part2, it is necessary for the moveable furniture part2to be released by the operator at least for a short time. In that way the friction ceases or the abutment damping element78can expand again so that the blocking element70can move into the evasion area73.

In that way—by pressure further being applied after the furniture part2has been released in the meantime—the moveable furniture part2can move out of the closed position SS along the triggering travel AW which is preferably 3.5 mm long into the over-pressed position ÜS and the lockable ejection device5is unlocked whereby the moveable furniture part2is ejected in the opening direction OR.