Abstract:
The invention relates to a drive device for a furniture part that is displaceably mounted in relation to a furniture body, in particular for a drawer or similar. The device includes an energy accumulator device, which supports the displacement of the furniture part. According to the invention, the displaceable furniture part can be essentially displaced into a fully open position by the energy accumulator device, thus partially discharging the energy accumulator device. The energy accumulator device is then re-charged during the closing operation of the displaceable furniture part. The energy accumulator device only acts on part of the displacement path of the furniture part.

Description:
This application is a continuation of International Application No. PCT/AT2005/000448, filed Nov. 10, 2005. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a drive device for a furniture part which is mounted movably relative to a furniture body, particularly for a drawer or the like, having an energy storage device which assists the movement of the furniture part. 
     The invention also relates to an item of furniture with a furniture part which is mounted movably relative to a furniture body, and also to a method of moving a furniture part of this kind into its open position. 
     According to the prior art, numerous embodiments of retraction devices are known, in which an energy storage device conveys the furniture part into the fully closed position. It is also known to provide such retraction devices with damping devices, which, if the movable furniture part is swung shut, at least reduce the banging noises occurring thereby, and thus also reduce the mechanical stress upon the system components. European Patent EP 0 391 221 describes a closure device for drawers, in which a displaceable rocker segment is brought into a stand-by position counter to the force of a spring when the drawer is pulled out. When the drawer is pushed in, the rocker segment is disengaged again by virtue of an entrainment member, wherein the rocker segment is being pulled back into its initial position by a spring. In so doing, the rocker segment entrains the entrainment member of the drawer, so that the drawer is retracted into its fully closed position. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to propose a drive device of the kind mentioned in the introduction, by means of which the movable furniture part can be moved into the fully open position, wherein this operation is intended to take place as uniform as possible. 
     According to the invention, the above object is achieved by virtue of the fact that a movable furniture part can be moved essentially into the fully open position by an energy storage device (energy storage member), during which the energy storage device is at least partly discharged. During the closure operation of the movable furniture part, the energy storage device is rechargeable, and the energy storage device is only effective over part of the path of movement of the furniture part. 
     By virtue of the energy storage device of the aforementioned kind, temporary coupling of the energy storage device with the movable furniture part is made possible, so that this latter can be moved into the fully open position. A movement of the movable furniture part in the direction of its closed position, starting from the fully open position, causes the energy storage device to be charged, so that a new stand-by position can be set up. During the opening procedure, the movable furniture part is initially freely movable until it is moved by a releasable coupling device back further towards the direction of its fully open position. 
     The opening of the drawer into the fully open position by the inventive drive device is advantageous in several ways. With the opening of short drawers, rebounding can be effectively prevented, particularly if there is damping over the last region of opening of the pull-out path. Another advantage is the ease of operation and the avoidance of accidental self-closure. If removably fitted inserts, or objects, are inside the drawer, which require the drawer to be pulled out fully in order for them to be removed, the drive device according to the invention can be used to advantage in such a situation. 
     A preferred embodiment of the invention provides that the energy storage device has a spring device with at least one spring. As a result, the drive device is simple in its construction and is inexpensive to make. Alternatively, or as an additional measure, the energy storage device can also be equipped with at least one pressurized gas storage device. In this case, it can also be advantageous to use the power from an external energy source—e.g. an electric motor—to form and/or assist the energy storage device. 
     Advantageously, the drive device has a rocker segment which is preferably spring-loaded and which can be releasably coupled to an entrainment member, and the entrainment member tensions the spring by the rocker segment during closure of the movable furniture part. The rocker segment then reaches a stand-by position which is arrested in self-locking manner, and then releases the entrainment member. The rocking of the rocker segment can thus be controlled with accuracy, and is not dependent upon the greater or lesser extent to which pull is exerted upon the movable furniture part. 
     In terms of its construction, the design can be such that the rocker segment is arranged on the furniture body, and the entrainment member is arranged on the movably mounted furniture part. However, the reverse solution also lies within the scope of the invention, namely, that the rocker segment is arranged on the movably mounted furniture part, and the entrainment member is arranged on the furniture body. 
     An advantageous embodiment of the invention results if the rocker segment is preferably guided in a displaceable manner linearly along a guide path. The rocker segment can be guided with accuracy along the path of movement provided for it, thus permitting reliable coupling which is free of clearance. The guide path can lie in a rail which is held by a fixing means to the side wall of the furniture body. 
     As an alternative, the design can be such that the rocker segment is mounted rotatably about an axis, and can be moved into a stand-by position which is arrested in a self-locking manner. This results in a space-conserving variant in comparison to the rocker segment which is guided in the guide path. 
     So that the movable furniture part is not brought into the fully open position with too much momentum, it is advantageously provided that a damping device is provided which dampens the movement of the furniture part over at least part of its path of opening. The damping device can essentially be based on any solutions known in the prior art, the use of linear dampers, or even rotary dampers, advantageously being possible. 
     The arrangement of the damping device can also vary. One embodiment provides that the damping device is arranged on the movable furniture part. It can also be advantageous if the damping device is arranged on a guide rail of a pull-out guide fitting. Alternatively, it can also be provided that the damping device is arranged on the rocker segment. Depending upon the application—e.g. in the case of drawers which are very heavy, or which are to be loaded so that they will become heavy—a combination of the afore-mentioned damping arrangements is provided within the scope of the invention. 
     Another advantageous embodiment of the invention results if a closure device is additionally provided by means of which the movable furniture part can be moved into its fully closed position. The movable furniture part can thus be moved within the region of the two end positions of the path of movement, both into the fully closed position as well as into the fully open position, gentle and smooth closure and opening operations being possible into both end positions. 
     The item of furniture according to the invention with a furniture part which is mounted movably relative to a furniture body is characterized in that it has a drive device of the afore-mentioned kind. 
     The method according to the invention for moving into its open position a furniture part which is movably mounted relative to a furniture body is characterized in that the movable furniture part is initially freely movable during the opening operation. Then, the furniture part is taken hold of by a detachable coupling device (rocker segment), is pulled further in the direction of its open position by an energy storage device, and a damping device provides damping over the last path of opening. 
     A preferred embodiment of the afore-mentioned method results if the damping effect of the damping device upon opening of the furniture part only begins when the detachable coupling device (rocker segment) has coupled the movable furniture part, or an entrainment member of same, to the energy storage device. If the movable furniture part, or the entrainment member thereof, is not coupled, then the movable furniture part could possibly move backwards when travelling onto the damping device, in which case smooth pulling out could not be ensured. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the present invention will be mentioned hereinafter in greater detail with the aid of the description of the drawings relating to the Figures: 
         FIGS. 1   a ,  1   b ,  1   c  show the front region of a pull-out guide fitting for drawers with a drive device according to the invention, and also detailed drawings on a larger scale, 
         FIGS. 2   a ,  2   b ,  2   c  show the chronological sequences of opening the drawer, according to an alternative embodiment, 
         FIGS. 3   a ,  3   b ,  3   c  show the embodiment from  FIGS. 1   a - 1   c  with an additional closure device, and also detailed drawings on a larger scale, 
         FIGS. 4   a ,  4   b  show a pull-out guide fitting with a closure device and the drive device from  FIGS. 2   a - 2   c  in detailed drawings on a larger scale, and 
         FIGS. 5   a - 5   f  illustrate the course of the closure operation of a drawer in chronological sequences. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1   a  shows the front region of a pull-out guide fitting  1  for drawers with the drive device  2  according to the invention.  FIG. 1   b  is a view of the detail D in  FIG. 1   a , and  FIG. 1   c  is a sectional drawing taken along the line A-A of  FIG. 1   a . The pull-out guide fitting  1  is in the open position, the drawer rail  6  being engaged with the drive device  2 . Other than in respect of the drive device  2 , the pull-out guide fitting  1  corresponds to the prior art, i.e. a carcass rail  3  is fixedly connected with a furniture body. Between the carcass rail  3  and the drawer rail  6  there is a central rail  8  which is displaceable relative to these two rails  3 ,  6 . The load between the rails is transmitted by means of rollers, balls or rolls, or conventional carriages, not shown. The drive device  2  is preferably disposed in the front half of the pull-out path of a drawer which is fixedly connected to the drawer rail  6 . The drive device  2  can be arranged between the side wall of the drawer and the side wall of the carcass rail  3 , or it can also be arranged under the bottom of the drawer. 
     The drive device  2 —as shown in  FIG. 1   b —comprises an energy storage device  10  in the form of at least one (tension) spring by means of which a drawer can be moved into its fully open position. The energy storage device  10  is pivotably connected to the fixing journal  11 , on the one hand, and communicates via the direction-changing member  12  with a rocker segment  14 . The rocker segment  14  can be of a forked configuration, and is displaceable along a guide path  13  by means of an engaging journal. The guide path  13  has a straight portion, in both end regions of which the arcuate portions  13 ′ and  13 ″ are arranged. 
     In the drawing shown, an entrainment member  15  (i.e., a first member) makes contact with the rocker segment  14  (i.e., a second member). The entrainment member  15  is secured fixedly in the rear region of the drawer rail  6 , or is formed thereon. However, the entrainment member  15  can also be secured directly to a side wall of the drawer. If the drawer is then opened, starting from its fully closed position, it is possible to initially move it freely. At that time, the spring-loaded rocker segment  14  is disposed in the arcuate portion  13 ″ in a stand-by position which is arrested in a self-locking way. When the drawer approaches its fully open position, the entrainment member  15  is grasped by the rocker segment  14 . When this happens, the rocker segment  14  is lifted by the entrainment member  15  out of the arcuate portion  13 ″, and is moved by spring force in the direction of the second arcuate portion  13 ′. In this position, the entrainment member  15  is able to be released again from the rocker segment  14 , so that free running of the entrainment member  15 , or of the drawer, is possible. As an alternative, the entrainment member  15  can also continue to be connected to the rocker segment  14 , which, of course, simultaneously denotes the fully open position. In order to move the drawer, or the entrainment member  15 , into the fully open position, it is advantageously provided that the energy storage device  10  is designed such that it does not become fully discharged when the drawer is in the fully open position. This means that, in that position, the spring(s) is/are at least partly tensioned, so that the rocker segment  14  is tensioned even when the drawer is fully open. 
     If the movable furniture part is closed, starting from its fully open position, then the entrainment member  15  becomes once again coupled to the rocker segment  14 , and the energy storage device  10  becomes recharged, i.e. the spring is tensioned. When the movable furniture part moves further in the direction of its closed position, the rocker segment  14  again takes up a stand-by position which is arrested in self-locking manner (rocker segment  14  in the arcuate portion  13 ′) and releases the entrainment member  15 , so that the drawer can be moved into the closed position. 
       FIG. 1   c  shows a sectional drawing along the axis A-A in  FIG. 1   a , in which the position of the rails  3 ,  6 ,  8  relative to one another is visible. For the sake of simplicity no load-transmitting members, such as balls, rolls, or the like, are shown. In order to prevent the drawer from reaching the fully open position with a loud banging noise, a damping device  17  is shown here by way of example, which can have at least one linear damper or rotary damper. 
       FIGS. 2   a ,  2   b ,  2   c  show chronological sequences of the opening procedure, according to an alternative embodiment of the invention. Instead of the rocker segment  14  which can be displaced in a linear manner, as shown in  FIGS. 1   a - 1   c , a V-shaped rocker segment  14  is provided which is mounted rotatably about an axis  18 . The energy storage device  10  comprises a spring which is coupled to the fixing journal  11 , on the one hand, and to the rocker segment  14 , on the other hand. The projecting flap  16  is arranged in the front region of the carcass rail  3 , and serves to receive the drive device  2 . In  FIG. 2   a , the rotatably mounted rocker segment  14  is disposed in a stand-by position which is arrested in a self-locking manner. This can be done easily by virtue of a detent, or by a lug disposed on the underside of the rocker segment  14  which co-operates with a cavity  21  formed in the flap  16 , as shown by way of example in  FIG. 2   b .  FIG. 2   b  also shows the entrainment member  15  which is already to be found in the engaged condition and which is displaced by spring force, to the right, in the direction of the open position.  FIG. 2   c  shows the essentially fully open position of the drawer rail  6  relative to the central rail  5 . In the embodiment shown, the entrainment member  15  remains in the section of the V-shaped rocker segment  14 , so that no free running of the drawer rail  6  is provided. If the drawer rail  6  is pushed in again, then operation can be completed in the sequence:  FIGS. 2   c - 2   b - 2   a . The energy storage device  10  is recharged, the spring is thus tensioned, and the rocker segment  14  is returned to the arrested stand-by position shown in  FIG. 2   a.    
       FIGS. 3   a ,  3   b ,  3   c  show the embodiment from  FIGS. 1   a - 1   c , wherein in addition to the drive device  2 , a closure device  19  is provided by means of which the movably mounted furniture part is movable into its fully closed position. The closure device  19  corresponds basically to the prior art, and can have a damping device which provides dampening over the last closure path of the drawer until it is in the fully closed position.  FIG. 3   a  shows the detail A from  FIG. 1   a , wherein from a constructional viewpoint the components of the closure device  19  correspond to the components of the drive device  2 . A rocker segment  14 ′ is guided displaceably along a guide path  13   a . However, in the rear region the guide path  13   a  has a straight section because in this fully closed position it is not absolutely necessary for the entrainment member  15  to be disengaged. If the drawer is then moved in the direction of its closed position, the entrainment member  15  becomes coupled to the rocker segment  14 ′. The rocker segment  14 ′ is lifted out of the arrested stand-by position, and is pulled by spring force into the most rearward closed position.  FIG. 3   c  shows the detail B with the drive device  2 , wherein the functional description can be deduced from  FIG. 1   b.    
       FIG. 4   a  shows a variant of the embodiment in  FIGS. 3   a - 3   c ,  FIG. 4   b  shows the view on a large scale of the detail A in  FIG. 4   a . In the front region of the pull-out guide fitting  1  there is a drive device  2  with a rotatably mounted v-shaped rocker segment  14  according to  FIGS. 2   a - 2   c , while the closure device  19  has a displaceably mounted rocker segment  14 ′. By virtue of the closure device  19  and the drive device  2 , the movable furniture part can be brought, with damping, into the respective end positions of the drawer. Clearly, any possible combination of rotatably mounted rocker segment  14  and displaceably mounted rocker segment  14 ′ in closure device  19  and drive device  2  is also possible. 
       FIGS. 5   a - 5   f  show schematically the course of a closure operation in chronological sequences. A movably mounted furniture part  7  in the form of a drawer is to be found in the fully open position in  FIG. 5   a . A damping device  17  in the form of a linear damper is disposed in the pushed in state, wherein an abutment  20  on the drawer  7  cooperates with a piston rod of the damping device  17 . The closure device  19  which is arranged in the draw-in region, and the drive device  2  on the pull-out side are shown, and, in the embodiment shown, are identical in design apart from the shape of the guide paths  13 ,  13   a . In  FIG. 5   a , the entrainment member  15  is disengaged from the rocker segment  14  of the drive device  2 . The entrainment member  15  can be fixed or formed on the drawer  7 , the furniture body, or on the pull-out rail, on the drawer-side, of a pull-out guide fitting. For the sake of simplicity, in  FIGS. 5   b - 5   f , only some of the reference numerals are shown. However, they correspond to the reference numerals of  FIG. 5   a , the same reference numerals denoting like parts. If the drawer  7  is closed ( FIG. 5   b ), the entrainment member  15  is temporarily coupled with the rocker segment  14 , so that the energy storage device  10  in form of a spring is tensioned. In  FIG. 5   c , the rocker segment  14  is disposed in a standby position which is arrested in self-locking manner and in which the entrainment member  15  is once again uncoupled. The drawer  7  is then freely movable over the region between the drive device  2  and the closure device  19 . 
     In  FIG. 5   b , the rocker segment  14 ′ of the closure device  19  is disposed in the standby position with tensioned energy storage device  10 ′. The entrainment member  15  can engage in the slot of the rocker segment  14 ′. By virtue of the tensioned spring of the energy storage device  10 ′, the entrainment member  15  is moved in the direction of its closure position ( FIG. 5   e ), and is advantageously damped over the final closure path, so that severe impact in the fully closed position can be avoided.  FIG. 5   f  shows the drawer  7  fully pushed into the furniture body. The opening operation can take place in like manner on the basis of  FIG. 5   f  to  FIG. 5   a.    
     The present invention is not limited to the embodiments which have been shown, but can encompass, or be extended to, any variants and technical equivalents coming within the scope of the subsequent claims. The indications pertaining to positions, which have been chosen in the description, e.g. above, below, side, etc., relate to the figure shown and described directly, and are to be applied logically to the new position in the event of a change of position. It will readily be appreciated that the drive device according to the invention can be arranged, not just on one side, but also on both sides of the drawer. This is particularly expedient if large drawers, or drawers which are loaded so that they are heavy, or front pull-out fitments, are to be moved. The course of movement can therefore be more effective and smoother, and guidance of the moved furniture part can be positively influenced thereby.