Abstract:
An ejecting device for a movable furniture part includes an ejector, which can be moved between a first and a second position, for ejecting the movable furniture part, a drive train having an electrical drive unit that drives the ejector and a gear mechanism arranged between the drive unit and the ejector and which has an output that acts on the ejector, and an open-loop or closed-loop control device for controlling the drive unit in an open-loop or closed-loop manner. A force accumulator is integrated in the gear mechanism between the drive unit and the output, and a monitoring device connected to the drive train can detect an unloading of the force accumulator and report the unloading to the open-loop or closed-loop control device. The open-loop or closed-loop control device activates the electrical drive unit to move the ejector back to the first position after detection of the unloading.

Description:
BACKGROUND OF THE INVENTION 
     The invention concerns an ejection device for a movable furniture part, in particular a door or drawer, comprising an ejector movable between a first position and a second position for ejecting the movable furniture part, a drive train having an electric drive unit for driving the ejector and a transmission arranged between the drive unit and the ejector and having a drive output acting on the ejector, and a control or regulating device for controlling or regulating the drive unit. 
     Electrically driven ejection devices are already known. For example, AT 007 158 U1 describes an ejector for a movable furniture part, wherein the drive unit can be triggered by applying a pulling force and/or a pushing force to the ejection device. In a specific embodiment in which the ejector includes two parts which are arranged telescopically one within the other, the movement of the movable furniture part away from the ejector can be detected after the termination of the ejection operation and the retraction process of the ejector can be triggered as a reaction thereto. A disadvantage in that respect is that the force storage means required for that detection is disposed in the ejection push rod itself, whereby detectability is dependent on the form of the ejection push rod. 
     WO 2006/017864 A1 concerns an ejection device for a movable furniture part, wherein a first roller is arranged at the free lever end and a second roller is arranged at a spacing from the free lever end. In an embodiment described therein, the pivotably mounted lever comprises two lever parts which can be prestressed relative to each other by a spring, and the position of one of those lever parts can be detected. In this case, that spring is provided after the drive output of the transmission and is thus a component of the actual ejector whereby in this case also detectability of unloading of the force storage means presupposes a given form for the ejector. 
     SUMMARY OF THE INVENTION 
     Therefore the object of the invention is to provide an ejection device which is improved over the state of the art. In particular, the invention seeks to provide that detection of unloading of the force storage means is effected independently of the form of the ejector. In other words, the invention seeks to provide an ejection device in which the ejector can in itself be of any desired configuration and nonetheless it is possible to draw a conclusion about the position of the ejector, from the transmission. 
     In the ejection device according to the invention, that object is achieved in that a force storage means is integrated in the transmission between the drive unit and the drive output. Unloading of the force storage means can be detected by a monitoring device connected to the drive train and can be signaled to the control or regulating device. After detection of the unloading of the force storage means, the control or regulating device activates the electric drive unit for moving the ejector back into the first position. 
     In an ejection device according to the invention a force storage means whose unloading can be detected and can be used as a trigger for retraction movement of the ejector is disposed between the drive unit and the drive output, that is to say it is therefore within the transmission of the drive train. As the drive output of the transmission acts on the ejector, the form of the ejector is independent of possible detectability of unloading of the force storage means. Accordingly, the transmission can be produced in the form of a structural unit and the ejection device can then be retro-fitted with ejectors of any desired shape or configuration. 
     In a preferred embodiment, the ejector is movable with a translatory movement. That represents a particularly simple form of force actuation on the movable furniture part by the ejector. In principle, however, the ejector could also be pivotable or movable in another form. 
     Preferably, the ejector can be in one piece with the drive output of the transmission. That reduces the complexity of the ejector and permits particularly simple production thereof. It will be appreciated that it is, however, also possible for the ejector and the drive output to be in the form of separate parts in order thereby to make the ejector independent of a transmission member. 
     The electric drive unit can include an electric motor. That can permit driven automatic movement of the ejector in the extension and retraction directions. 
     In a particularly preferred embodiment of the invention, the drive train is of such a design that the transmission has two gears which are movable limitedly relative to each other. That limited relative mobility permits the interposition of a force storage means therebetween, whose unloading can be detected as a further consequence. 
     If the two gears are arranged in mutually coaxial relationship, that can permit a particularly compact structure. 
     In a further embodiment, the first gear is connected to the drive unit by a worm and the second gear is connected to the ejector. That embodiment permits a compact structure for the drive train with at the same time a minimum number of transmission components. In principle, however, the gears can be connected to any number of transmission components. 
     It has proven to be particularly advantageous if the force storage means is between the two gears. The force storage means can also be loaded and unloaded only in a limited operating range, due to the limited relative mobility of the two gears. That prevents excessive stressing of the force storage means, in particular beyond the limits of the intended operating range. 
     A particularly advantageous embodiment of the invention is one in which the gears can be prestressed relative to each other by the force storage means. That permits particularly easy detection of unloading of the force storage means insofar as the monitoring device is connected to that gear which is moved upon unloading of the force storage means. 
     A further advantageous embodiment of the invention is of such a design that the monitoring device has a measuring potentiometer. In principle, the monitoring device may also include other movement detectors or other sensors by which unloading of the force storage means can be detected. 
     Further, the monitoring device can be connected to the drive train by means of at least one monitoring gear. As a result, the monitoring device can be connected directly to the transmission of the drive train and thus register movements within the transmission. 
     It has proven to be particularly advantageous in that respect if the monitoring gear engages that gear which is connected to the ejector. In that case, the movement of the ejector is detected directly, in particular that movement after removal of the movable furniture part in the extended second position of the ejector. It is however also possible for the monitoring gear to be coupled to the transmission at another location. 
     In a further preferred embodiment of the ejection device, the force storage means includes at least one spring which is preferably a coil spring. That kind of force storage means is particularly simple and inexpensive. Equally however the force storage means can include a fluid pressure storage means or a magnet. 
     In a preferred embodiment of the invention, unloading of the force storage means is effected after attainment of the second position ( FIG. 5 ) of the ejector by removal of the force actuation acting against the loaded force storage means. If removal of the force actuation is effected by moving the movable furniture part away from the ejector, whereby the force storage means moves the ejector into the third position ( FIG. 6 ), opening of the movable furniture part for example can be detected after ejection and the drive unit can be caused by way of the control or regulating device to move the ejector back into the first position ( FIG. 7 ). It is possible in that way, for example, to prevent anyone from injuring themselves when the article of furniture is opened, on the extended ejector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the invention will be described more fully hereinafter by means of the specific description with reference to the embodiments illustrated by way of example in the drawings, in which: 
         FIG. 1  shows a perspective view of an article of furniture with an incorporated ejection device, 
         FIG. 2  shows a perspective view of the ejection device, 
         FIG. 3  shows an exploded view of the ejection device, 
         FIGS. 4 and 4A  show a side view of the ejection device in the first retracted position with the furniture part closed and an enlarged detail view, 
         FIGS. 5 and 5A  show a side view of the ejection device in the second extended position with the furniture part in contact and an enlarged detail view, 
         FIGS. 6 and 6A  show a side view of the ejection device with the furniture part removed (third position) and an enlarged detail view, 
         FIGS. 7 and 7A  show a side view of the ejection device with the ejector retracted again in the first position and an enlarged detail view, 
         FIG. 8  shows a perspective view of the two assembled gears of the transmission, which are limitedly movable relative to each other, 
         FIG. 9  shows a perspective view of the loaded force storage means in the form of a coil spring, 
         FIG. 10  shows a perspective view of the unloaded force storage means in the form of a coil spring, 
         FIG. 11  shows a side view of the loaded force storage means in the form of a fluid pressure storage means, 
         FIG. 12  shows a side view of the unloaded force storage means in the form of a fluid pressure storage means, 
         FIG. 13  shows a schematic block circuit diagram of the essential components of the ejection device with the force storage means loaded, and 
         FIG. 14  shows a schematic block circuit diagram of the essential components of the ejection device with the force storage means unloaded. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows an article of furniture  9  including a furniture carcass  14  and a movable furniture part  2  fixed movably to the furniture carcass  14  by means of two hinges  15 . An ejection device  1  is mounted at the bottom right corner of the furniture carcass  14 . In particular, the housing  16  and the ejector  3  can be seen in this view in the retracted first position of the ejection device. 
       FIG. 2  shows the ejection device  1  in the retracted first position of the ejector  3 . In this embodiment of the invention, the ejector  3  is in one piece with the drive output  20  of the transmission  19 . The monitoring device  8  is formed here by a measuring potentiometer coupled to the transmission member  11  by a monitoring gear  13 . 
       FIG. 3  shows an exploded view of the ejection device  1  comprising housing  16 , electric drive unit  5 , worm  12  connected to a drive shaft of the drive unit  5 , first gear  10 , second gear  11 , force storage means  6  arranged between first and second gears  10  and  11  and in the form of two coil springs  6   a , a monitoring gear  13  and a monitoring device  8  connected thereto as well as the drive output  20  of the transmission  19  and the ejector  3 . 
       FIGS. 4 and 4A  show a side view of the ejection device  1  when the movable furniture part  2  is in the closed position and thus the ejector  3  is in its first retracted position. In that case,  FIG. 4A  shows a view of a portion on an enlarged scale in particular of the two gears  10  and  11  and the force storage means  6  which in this case is in the form of two coil springs  6   a . The electric drive unit  5  is connected to the first member of the transmission  19 , here in the form of the worm  12 . During the ejection process that worm  12  moves the first gear  10  in the counter-clockwise direction whereby the force storage means  6   a  can be loaded to that point at which the second abutment  18  of the first gear  10  contacts the hook-shaped part of the second gear  11  and thus that second gear  11  is also moved in the counter-clockwise direction. The second gear  11  is connected to the drive output  20  of the transmission  19  whereby the ejector  3  is extended from the housing  16  with a translatory movement (towards the right) and thus moves the movable furniture part  2  in the opening direction. The monitoring device  8  connected to the monitoring gear  13  is also visible here. That monitoring gear  13  is coupled to the second gear  11  whereby the rotary movement thereof can be monitored. In particular, unloading of the force storage means  6   a , which is only limitedly made possible by the abutments  17  and  18 , can thereby also be detected. 
       FIGS. 5 and 5A  show a side view of the ejection device  1  in the extended second position of the ejector  3  which has thus correspondingly moved the movable furniture part  2  in the opening direction. In that case,  FIG. 5A  shows a view on an enlarged scale of a portion of the detail  5 A. In that view, the movable furniture part  2  has been ejected in the opening direction by the ejector  3  but still remains thereat whereby a force actuation K corresponding to the illustrated arrow acts against the ejector  3 . Because of that force actuation K, it is not possible for the loaded force storage means  6   a  to unload. The force actuation K acts in a translatory movement towards the left on the drive output  20  by means of the ejector  3  whereby a force in opposition to unloading of the force storage means  6   a  acts on the latter in the second gear  11 . 
       FIGS. 6 and 6A  show a side view of the ejection device  1 , wherein the movable furniture part  2  has been moved still further away in the opening direction, after ejection has been effected by the ejector  3 . Removal of the movable furniture part  2  from the ejector  3  which is in its second extended position means that the force actuation K acting against the ejector  3  is also removed (illustrated by crossed out arrow). Because of the force action which also disappears therewith against the loaded force storage means  6   a  due to the second gear  11  by means of the drive output  20 , it is now possible for the loaded force storage means  6   a  to be able to unload. That unloading has the result that the second gear  11  moves to a limited extent in the counter-clockwise direction, more specifically until the hook-shaped part of the second gear  11  which prior to unloading of the force storage means  6   a  bears against the second abutment  18  is moved by unloading of the loaded force storage means  6   a  in the counter-clockwise direction until the rear part of the hook-shaped part of the second gear  11  bears against the first abutment  17 . By means of the transmission action, that limited rotational movement in the counter-clockwise direction of the second gear  11 , by way of the drive output  20 , is converted into a translatory movement towards the right of the ejector  3  which can now be extended correspondingly further into its third position. By virtue of coupling of the monitoring gear  13  to the second gear  11 , that unloading of the force storage means  6   a  by means of transmission action can be registered as a rotary movement in the clockwise direction of the monitoring gear  13  by the monitoring device  8  which is connected to the monitoring gear  13 , whereupon, according to the invention, the electric drive unit  5  is actuated or activated by the control or regulating device  7  (not shown here) to move the ejector  3  back into the first retracted position. 
       FIGS. 7 and 7A  show a side view of the ejection device  1  after the ejector  3  was moved back again into its first retracted position after detection of unloading of the force storage means  6   a , by the drive unit  5 . Retraction of the ejector  3  into its first position is achieved by the electric drive unit  5  rotationally moving the first gear  10  in the clockwise direction by means of a transmission action. As after unloading of the force storage means  6   a  has occurred the hook-shaped part of the second gear  11  bears against the first abutment  17 , that second gear  11  is also rotationally moved in the clockwise direction. That second gear  11  acts on the drive output  20  of the transmission  19  and thus leads to a translatory movement towards the left of the ejector  3  to its first retracted position. 
       FIG. 8  shows a perspective view of the two assembled gears  10  and  11  which are movable limitedly relative to each other by a hollow space (not visible here) in the first gear  10  and a hook-shaped part (also not visible here) provided on the second gear  11 . 
       FIG. 9  shows the relative position of the two gears  10  and  11  with respect to each other when the force storage means  6   a  are loaded. In this case, the hook-shaped part of the second gear  11  bears against the second abutment  18  of the first gear  10 . 
       FIG. 10  shows the relative position of the two gears  10  and  11  with respect to each other when the force storage means  6   a  are unloaded. In this case, the rear part of the hook-shaped part of the second gear  11  bears against the first abutment  17  of the first gear  10 . 
       FIG. 11  shows alternative force storage means  6 , here in the form of fluid pressure storage means  6   b . The force storage means  6   b  are loaded in the illustrated relative position of the two gears  10  and  11  with respect to each other. 
       FIG. 12  shows the relative position of the two gears  10  and  11  with respect to each other when the two force storage means  6  which here are in the form of fluid pressure storage means  6   b  are unloaded. 
       FIG. 13  diagrammatically shows the most important components of the ejection device  1 , comprising electric drive unit  5 , the drive member of the transmission  19  in the form of a worm  12 , first gear  10 , force storage means  6 , second gear  11 , drive output  20  of the transmission  19  and ejector  3 , as well as the monitoring gear  13  coupled to the second gear  11 , the monitoring device  8  connected thereto, and the control or regulating device  7 . In this view, the ejector  3  is in its second extended position, wherein the movable furniture part  2  still bears against the ejector  3  and thus a force actuation K acts in opposite relationship to the extension direction of the ejector  3 . The force action A in the drive train  4  diagrammatically shows that in principle the force actuation K acts in opposite relationship to the force action A in the drive train  4 . The ejector  3  is in its second extended position and the force storage means  6  is loaded. 
       FIG. 14  shows the most important components of the ejection device  1  after extension of the ejector  3  into its second position and after removal of the movable furniture part  2  from the ejector  3  in the opening direction. Due to the removal of the movable furniture part  2 , the force actuation K acting by the ejector  3  and the transmission members  20  and  11  against the loaded force storage means  6  disappears and the force storage means  6  can be unloaded. As a result, the ejector  3  is moved further in the extension direction into its third position by transmission members  11  and  20 , and that movement within the transmission  19  is detected by the monitoring device  8  by the monitoring gear  13 . That detection causes the control or regulating device  7  to activate the electric drive unit  5  to move the ejector  3  back into its first retracted position again by the transmission  19 .