Abstract:
A sliding arrangement, in particular an extension apparatus for drawers, sliding doors, hinged doors, etc., has an extending arrangement which comprises a sliding piece ( 21 ) that is displaceable by means of a spring element ( 22 ) between an inserted position and an extended position. In order to enable user-friendly opening of the drawer, provision is made according to the present invention that the sliding piece is displaceable over a first displacement distance in spring-impinged fashion, and in an adjacent second displacement distance is displaceable without spring impingement in a free-running portion of the extension apparatus.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a sliding arrangement, in particular an extension apparatus for drawers, sliding doors, hinged doors, etc., having an extending arrangement which comprises a sliding piece that is displaceable by means of a spring element between an inserted position and an extended position. 
     The invention further relates to a method for operating a drawer. 
     2. Description of the Prior Art 
     DE 10 2007 008 688 A1 discloses a retraction apparatus for drawers. It comprises a spring-impinged coupling piece that is movable upon displacement of the drawer between a retracted position and a pulled-out position. The coupling piece is embodied in this context as a tilting segment that is moved by a follower that is installed on the drawer. When the tilting segment has reached the pulled-out position it releases the follower, and the drawer can be pulled out further in free-running mode, uninfluenced by the retraction apparatus. When the drawer is closed again, it can be displaced in free-running mode until the follower is captured by the tilting segment. 
     The previously tensioned spring then pulls the drawer into the closed position. To prevent a hard impact by the drawer in this context, the retraction motion is decelerated with a damper. 
     Handleless drawers are becoming increasingly desirable for reasons of design. Such drawers cannot always easily be opened with the known retraction apparatuses, since the drawer is held in the closed position by the action of the spring. 
     Also known from the existing art are extension apparatuses for drawers. These comprise an extending arrangement that, after unlatching thereof, move the drawer from a closed position into a partly open position. In this operation, a spring is discharged in order to make the motion energy available. When the extension operation controlled by the spring is complete, the drawer can be grasped and completely opened. The spring is then tensioned again upon closing of the drawer. The spring must thus be configured so that it guarantees a sufficiently long extension travel so that the drawer can be conveniently grasped. The springs necessary for this, having a long spring travel, have the disadvantage that a great deal of energy must be introduced by the user into the spring in order to tension the spring upon closing of the drawer. This is, however, perceived as bothersome, since a counter-force must be overcome over a large portion of the closing distance. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to improve operator convenience in the context of a drawer or other sliding element. 
     This object is achieved in that the sliding piece is displaceable over a first displacement distance in spring-impinged fashion, and in an adjacent second displacement distance is displaceable without spring impingement in a free-running portion of the extension apparatus. 
     According to the present invention the overall ejection travel made available by the sliding arrangement is thus divided into two displacement distances. In the region of the first displacement distance, the spring element is effective. This accelerates the sliding piece and thus the coupled drawer within this first partial distance. The result is that a kinetic energy is introduced into the drawer and the sliding piece, which energy moves the drawer and the sliding piece in the region of the second displacement travel. After the second displacement distance has been traveled, the drawer is sufficiently open that it can be conveniently grasped and completely pulled out. Advantageously, the drawer travels against a stop at the end of the second displacement distance, so that a defined partly open position is achieved. 
     Upon closing of the drawer, only the relatively short spring travel of the spring element needs to be overcome; in accordance with the formula U=(c*x 2 )/2 (U=energy, c=spring constant, x=spring travel), relatively little energy is necessary. The present invention thus takes account of the fact that the required closure energy scales as the square of the spring travel, which should therefore, in accordance with the invention, be kept low. 
     The ejection force, on the other hand, is calculated using the formula F=c*x. Here the spring constant c should be selected so that for a small ejection distance, the resulting force (F) is sufficient to accelerate the drawer and guide it through the second displacement distance. 
     According to a preferred configuration of the invention, provision can be made that the combined total displacement distance, made up of the first and the second displacement distance, is equal to at least 60 mm, by preference ≧70 mm. It is then possible, with usual drawer embodiments, to conveniently reach behind the drawer front and pull the drawer completely out. This is advantageous in particular with handleless drawer fronts. Advantageously, the sliding arrangement according to the present invention is dimensioned so that the energy of motion introduced into the sliding piece by means of the spring element is so great that the sliding piece travels automatically to the end of the second displacement distance. 
     A sliding arrangement according to the present invention can be characterized in that the spring element is held in a pre-tensioned position at a stop at the end of the first displacement distance. This further shortens the theoretically available spring travel of the spring element, thereby appreciably decreasing the energy needed to load the spring. At the same time, however, the quantity of available energy provided by the spring element with the drawer in the closed position remains unchanged. 
     A particularly preferred inventive configuration is such that a coupling piece is indirectly or directly coupled to the extending arrangement, the coupling piece being displaceable by means of a spring between a retracted position and a pulled-out position. With this embodiment, the extension apparatus is combined with a retraction apparatus. To open the drawer, firstly the extending apparatus is triggered and, by means of the spring element, traverses the first displacement distance in positively controlled fashion. The sliding piece then travels passively through the second displacement distance. At the end of the second displacement distance, the coupling piece can then be moved against the force of the spring out of the retracted position into the pulled-out position. The spring is then available later, upon closing of the drawer, in order to pull the drawer into the closed position. If the embodiment is such that the sliding piece still has residual kinetic energy at the end of the second travel distance, that energy can then also be transferred, for example, into the coupling piece; the result is that the spring is already moved into a partly pre-tensioned position, which ergonomically optimizes the drawer opening operation. 
     A controlled closing motion can be achieved by the fact that a damper damps the motion of the coupling piece from the pulled-out position into the retracted position. 
     A preferred variant embodiment of the invention can be characterized in that in the pulled-out position, the coupling piece is held by means of a positioning arrangement in a parked position; and that in the parked position, the sliding piece is displaceable relative to the coupling piece. The result is that the retraction apparatus has a simple construction, and that the operating sequence of the retraction apparatus can advantageously be integrated into the motion sequence of the drawer. 
     A simple and economical construction for a retraction apparatus according to the present invention is produced if provision is made that the extending arrangement is held by means of the spring element in the inserted position in pre-tensioned fashion. Upon actuation of the extending arrangement when the drawer is in the closed position, the spring element can transfer its spring energy to the sliding piece. The drawer is thereby brought into the partly opened position. 
     A particularly preferred inventive configuration can be characterized in that the extending arrangement comprises an overtravel mechanism to disengage the inserted position. The retraction apparatus can thereby be handled in particularly user-friendly fashion. To trigger the extending arrangement it is possible, depending on the design of the drawer, for example to operate the overtravel mechanism by simply pushing the drawer front. 
     If provision is made that the extending arrangement comprises a carrier, and that a control element, in particular a latch, which enables a displacement of the sliding piece relative to the carrier, is effective upon a displacement of the sliding piece from the extension position into the insertion position, a triggered extending arrangement can then be reloaded in simple fashion. 
     In order to prevent inadvertent triggering of the extending arrangement, one inventive variant is such that the sliding piece is secured in the inserted position by means of an immobilizing piece. 
     A preferred variant embodiment of the invention is such that a control element of the extending arrangement locks, upon closure of the drawer, against an enclosure-mounted blocking element upon a displacement of the extending arrangement from the extended position into the insertion position. 
     Reliable operation of the retraction apparatus is guaranteed by the fact that the control element secures the insertion position of the extending arrangement at least in sub-regions of the displacement, effected by the spring, of the coupling piece. 
     Actuation of the extending arrangement occurs easily thanks to the fact that the control element is displaceable out of the retracted position toward a holding piece in order to unlatch the extending arrangement. 
     The object of the invention is also achieved with a method for operating a drawer or the like, such that with the drawer in the closed position, an extending arrangement is triggered which moves the drawer out of the closed position into a partly open position, such that in a first travel distance the drawer is accelerated by means of a spring element of an extending arrangement; and that subsequently to the first travel distance, in a second travel distance the drawer is moved in a free-running portion (F) of the extending arrangement. 
     Here again, the extending arrangement serves for convenient opening of the drawer from the closed position. 
     If the invention is such that the drawer is pulled out of the partly open position, and this pulling motion is used to tension a spring, the spring tension can later, in the context of the closing operation, pull the drawer into the closed position. 
     This sequence can be implemented particularly conveniently by the fact that during opening of the drawer from the partly open position, a coupling piece is brought out of a retracted position into a pulled-out position; and that upon reaching the pulled-out position, the coupling piece is brought into a parked position and the coupling between the extending arrangement and the coupling piece is disengaged. 
     Operating convenience, especially for handleless drawers, etc., is high if provision is made that an overtravel mechanism is actuated in order to release the extending arrangement from the closed position. 
     If provision is made that upon a motion of the drawer out of an opened or partly opened position toward the closed position, firstly the extending arrangement is displaced in its free-running portion (F) and then the spring element of the extending arrangement is tensioned in order to move the sliding piece from the extension position into the inserted position, the extending arrangement is then brought into the insertion position upon closing of the drawer, so that this operation becomes integrated into the “natural” motion sequence of the drawer, this being perceived as particularly user-friendly. 
     For a smooth closing operation, provision can be made that the extending arrangement is pulled by means of the spring into the closed position of the drawer, and at the same time is decelerated by means of a damper. 
     To tension the extending arrangement, provision can be made that upon closing of the drawer etc., the extending arrangement is moved with a control element onto a blocking element. This enables a low part complexity. 
     It is advantageous in this context that the blocking element is moved onto the blocking element in the interior of the enclosure. This enables reliable operation and protected accommodation of the actuation point. A further result is operation that is clearly defined and readily understandable by the user. 
     One inventive variant is such that the extending arrangement is brought from the extension position into the insertion position immediately before the coupling piece is pulled in with the spring. 
     The invention will be explained in further detail below with reference to an exemplifying embodiment depicted in the drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 to 10  are side views of a retraction apparatus, partly in section and in various operating positions. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a retraction apparatus such as the one used, for example, in drawers. Utilization in other components to be moved, such as doors, hatches, etc., is also conceivable. The retraction apparatus encompasses a base part  40  and a housing  10 , each of which is mountable on a housing enclosure (not depicted). Also provided is an extending arrangement  20  that is arranged on a drawer (likewise not depicted). 
     Housing  10  is equipped with screw receptacles  11 . 1  that make possible enclosure-side mounting. Housing  10  has two side walls  11 , spaced in parallel fashion apart from one another, into which guides  11 . 2  are recessed. Guides  11 . 2  comprise a slot-shaped aperture that opens into a widened recess  11 . 21 . Guides  11 . 2  of the two side walls  11  align with one another. 
     A damper  12  is accommodated in housing  10 . Damper  12  is embodied as a fluid damper, in the present case as an air damper. The use of an air damper has the advantage that in the event of damage, liquid cannot emerge and contaminate the drawer contents. Damper  12  comprises a cylinder  12 . 6  in which a piston  12 . 2  is pulled out starting from the inserted position shown in  FIG. 1 . In the context of the return motion of piston  12 . 2 , it works against an air cushion, the air pressure being continuously dissipated. For this purpose, a small opening is present in an insert  12 . 3 , through which opening the compressed air can escape in controlled fashion. At its end facing away from insert  12 . 3 , piston rod  12 . 1  possesses a head segment  12 . 4  that forms a pivot bearing  12 . 5 . A coupling piece  13  in the form of a tilting element is held pivotably on pivot bearing  12 . 5 . The pivoting motion proceeds around a pivot axis extending perpendicular to the image plane in accordance with  FIG. 2 . A spring holder  13 . 1 , which holds one end of a spring  14 , is arranged on coupling piece  13 . The other end of spring  14  is suspended on the housing side. 
     Coupling piece  13  possesses a trigger  13 . 2  that is arranged at a distance from the pivot axis. Also present on coupling piece  13  is a follower  13 . 4  that is shaped via a spring element  13 . 5  on an arm  13 . 3 . A connecting part  30  of an extending arrangement  20  is detachably connectable to follower  13 . 4 . 
     Extending arrangement  20  encompasses connecting part  30 , the purpose of which is to create the detachable coupling to coupling piece  13 . For this, connecting piece  30  has, on a holder  32 , a latch  33  that can be coupled in the region between trigger  13 . 2  and follower  13 . 4 . Holder  32  further carries, by means of a pivot bearing point  34 , a control element  35  in the form of a lever. At its free end facing away from holder  32 , control element  35  is fitted with a rotatable track roller  37  and a rotatable locking roller  38 . A stop  36  is shaped on between pivot bearing point  34  and locking roller  38 . A carrier  31  adjoins holder  32 . 
     A plunger  24  is held via a threaded connection on carrier  31  at the end facing away from holder  32 . For this, plunger  24  is screwed with an external thread  24 . 1  into a threaded receptacle of carrier  31 . Plunger  24  carries a snap-lock ring  24 . 2 . The latter is held, freely rotatably in a circumferential direction, in a bearing receptacle of plunger  24 . Snap-lock ring  24 . 2  comprises a snap-lock element that is guided in a control cam  23  of a hollow cylinder of a sliding piece  21 . 
     Control cam  23  is recessed, in the form of a groove, into the inner wall of sliding piece  21 . Control cam  23  and snap-lock ring  24 . 2  of plunger  24  form an overtravel mechanism. The mode of operation in this context is similar to that in a ballpoint pen, plunger  24  constituting the pushbutton of the ballpoint pen. A spring element  22  in the form of a helical spring is inserted into sliding piece  21  and is secured against the walls of the hollow cylinder to prevent buckling. 
     Holder  32  is guided, with a hinge pin constituting pivot bearing  34 , displaceably in a linear guide  34 . 1 . The wall constituting linear guide  34 . 1  carries a shaped element  39  that constitutes a countersurface  39 . 1  and a running surface  39 . 2 . Base part  40  is U-shaped in cross section. It comprises a mounting segment  41  having bores  43  for bolting to a furniture enclosure. A partition  42  adjoins mounting segment  41  perpendicularly. Partition  42 , mounting segment  41 , and a further partition parallel to the latter carry a shaped-on, obliquely oriented blocking surface  46  as well as a holding piece  47 . In addition, a blocking element  44  is articulated pivotably on mounting segment  41  and is held, by gravity and/or by a spring element, in the initial position shown in  FIG. 1 . Blocking element  44  comprises two oppositely oriented control cams  44 . 1 ,  44 . 2 . 
     The mode of operation of the retraction apparatus according to the present invention will be explained in further detail below with reference to  FIGS. 1 to 10 . 
       FIG. 1  shows the initial position of the retraction apparatus, i.e. the position in which the drawer is located when closed. This represents the position in which coupling piece  13  is in the retracted position. The overtravel mechanism is in a snap-lock position, snap-lock ring  24 . 2  being locked against a snap-lock projection of control cam  23 . Blocking element  35  is held by means of a stop  35 . 1  on holder  32  in an elevated unlatched position. To release the overtravel mechanism, an overtravel Ü is introduced into, for example, the drawer front in the direction of the actual drawer closing motion. This overtravel Ü is introduced via a sliding piece  21  bolted to the drawer. In this context, sliding piece  21  shifts a small amount farther, against the pre-tension of spring element  22 , in the direction of overtravel Ü with respect to plunger  24 . As a result, the snap-locked position of snap-lock ring  24 . 2  in control cam  23  is disengaged, and snap-lock ring  24 . 2  is rotated in a circumferential direction until it arrives in a linear segment of control cam  23 . To allow overtravel Ü to be carried out, latch  33  is braced against trigger  13 . 2 . 
     Once the drawer has been pushed and unloaded, sliding piece  21  is brought, as a result of the released snap-lock connection between snap-lock ring  24 . 2  and control cam  23 , out of its inserted position ( FIG. 1 ) into the extended position ( FIG. 2 ). This displacement S is brought about by spring element  22 , which holds sliding piece  21  under pre-tension in the inserted position. The total displacement distance traveled by sliding piece  21  in this context is subdivided into a first displacement distance and a second displacement distance. 
     Within the first displacement distance, spring element  22  is effective. It is braced at its one end against sliding piece  21  and at its other end with respect to plunger  24 . Once plunger  24  has been unlatched by means of overtravel mechanism U, spring element  22  can slacken, sliding piece  21  being guided through the first displacement distance in response to spring element  22 . At the end of the first displacement distance, spring element  22  is in its completely slackened state. This is then followed by the second displacement distance as a free-running portion F. In this region, no spring force acts on sliding piece  21 . Instead, the kinetic energy of sliding piece  21 , generated in the first displacement distance, is utilized to travel through free-running portion F. At the end of the second displacement distance, the displacement motion of sliding piece  21  is limited with a stop. The stop couples sliding piece positively to plunger  24  in the direction of sliding motion S (according to  FIG. 2 ).  FIG. 2  shows the completely extended position of sliding piece  21  after the first and the second displacement distance have been traveled through. Because the drawer is coupled to sliding piece  21 , it is partly opened in accordance with the displacement travel of the sliding piece. 
     When the position shown in  FIG. 2  has been reached, the drawer can be conveniently grasped and pulled manually into a further partly open position or completely into the open position. The extending arrangement coupled to the drawer is then, in this context, moved in opening direction Ö. Because coupling piece  13  is coupled, with latch  33 , to extending arrangement  20 , coupling piece  13  is also moved in opening direction Ö (see  FIG. 3 ), coupling piece  13  being guided in guide  11 . 2 . Coupling piece  13  entrains piston rod  12 . 1  of damper  12  and thus displaces piston  12 . 2 . At the time, the spring is also tensioned. Coupling piece  13  is pulled by extraction apparatus  20  until follower  13 . 4 , guided in guide  11 . 2 , arrives in the region of recess  11 . 21 . Because spring  14  acts eccentrically with respect to pivot axis  12 . 5 , coupling piece  13  is tilted around pivot axis  12 . 5 , and follower  13 . 4  drops into recess  11 . 21 , in that context coming out of engagement with holder  32 . Because the connection between extending arrangement  20  and coupling piece  13  is now disengaged, the drawer can be further pulled out in free-running mode, as  FIG. 4  illustrates. In this context, track roller  37  also deflects blocking element  44  against its control cam  44 . 1  and lifts it upward against the direction of gravity. Track roller  37  moves past blocking element  44 , and control element  35  departs from fitting base part  40  through opening  45 . 
       FIG. 4  shows a further partly open position. 
     Upon closing of the drawer (closing direction S) and thus in the context of the transition of the retraction apparatus from  FIG. 4  to  FIG. 5 , track roller  37  encounters control cam  44 . 2  of blocking element  44 , which is blocked in this direction. The roller proceeds there against the direction of gravity until locking roller  38  encounters running surface  39 . 2 , as shown by  FIG. 6 . Connecting part  30  can now be pushed no farther in closing direction S. Closing motion S now causes plunger  24  to become inserted into sliding piece  21 ; plunger  24  then firstly travels through free-running portion F, and spring element  22  is then tensioned until plunger  24  has arrived at its snap-locked position (snap-lock ring  24 . 2  and control cam  23 ). Extending arrangement  20  is then tensioned again, and is in its inserted position. In the course of this operation, locking roller  38  rolls on running surface  39 . 2  until, at the end of running surface  39 . 2 , it travels over an edge  39 . 3  that conveys it into countersurface  39 . 1 . 
     Control element  35  then, as shown in  FIG. 7 , pivots into its blocked position because of the fact that track roller  37  is continuing to run onto blocking element  44 . Locking roller  38  abuts against countersurface  39 . 1  and blocks any inadvertent triggering of the extending arrangement out of the inserted position. 
     As  FIG. 7  shows, immediately after extending arrangement  20  has been tensioned, latch  33  encounters trigger  13 . 2  and tilts it around pivot bearing  12 . 5 . In that context, guide elements  13 . 6  are lifted out of recess  11 . 21  and coupling piece  13  is disengaged. Guide elements  13 . 6  then arrive in the region of guide  11 . 2 , and spring  14  can pull coupling piece  13  back into the retracted position. Damper  12  damps this retraction motion. With the coupling piece, latch  33  is pulled against follower  13 . 4  (see  FIG. 8 ); and the drawer is also automatically pulled, via sliding piece  21 , into the closed position. In the context of this motion operation illustrated by  FIGS. 8 and 9 , track roller  37  travels over holding piece  47 . With the drawer in the closed position, control element  35  drops, by gravity and/or by spring action, into the region below holding piece  47 , as  FIG. 10  shows.  FIG. 10  is once again identical to  FIG. 1 , and shows the initial position in which the drawer is ready for another actuation. 
     Housing  10  and base part  40  are usually mounted on the furniture enclosure. It is also conceivable, however, to mount these parts on the drawer. Extending arrangement  20  is then also attached to the other respective furniture component. 
     The arrangement according to the present invention can be arranged laterally in the region of one or both of the drawer walls extending in the drawer motion direction. The retraction guide can also be part of the drawer&#39;s pulling-out guide. It can furthermore also be arranged centrally under the drawer bottom. Extending arrangement  20  is then, for example, held on the drawer front below the drawer bottom. Housing  10  is then arranged laterally on the furniture enclosure. Coupling of these components then takes place by incorporation of a crossmember or drawer as a connecting member. 
     References herein to a spring being “tensioned” may also be described as loading of the spring. This refers to the storing of potential energy in the spring and may include either tensile or compressive loading of the spring depending on the type of spring used.