Patent Abstract:
An improved locking device is essentially characterized by the following features: at least two recessed sections extend radially outwards from the central axis and are arranged at regular angular intervals from one another, a setting member or rotary member is provided in the inside of the pot-like or housing-like fixed element; the rotary member comprises an actuation portion with a locking element which is axially offset in the direction of the base; the locking element has a structure provided with locking arms which project radially outwards, so that the thus designed locking element can be axially inserted through the recess.

Full Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This application is the U.S. national phase of International Application No. PCT/EP2004/011573 filed 14 Oct. 2004 which designated the U.S., the entire contents of which are hereby incorporated by reference. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   FIELD 
   The technology herein relates to a locking arrangement for fixing two items of furniture to one another. 
   BACKGROUND AND SUMMARY 
   Unit-furniture systems in their wide-ranging forms are sufficiently well known. Box-shaped office furniture systems or shelving systems are also very popular. These can be assembled with a high degree of variability for example from individual container-shaped or generally box-shaped basic units, which are sometimes also referred to below as modules. The modules may be left open for example, but may also be provided at their front with a wide range of flaps. Drawer elements may also be incorporated, etc. 
   Such a shelving system which can be assembled using a modular method of construction is then faced for example with the problem of how to fix the individual modules as simply as possible yet effectively to one another so that a stable overall construction finally results. 
   An exemplary illustrative non-limiting implementation provides an improved locking system for items of furniture, in particular for box-shaped modular or basic units, in order to fasten or fix such individual parts to one another. 
   An exemplary illustrative non-limiting implementation provides a highly efficient connecting system with which the individual items of furniture to be connected can be provided at the factory. The basic principle is such that any desired items of furniture, for example box- or container-shaped basic or modular units, provided with corresponding connecting and locking devices can be placed one on top of the other so that it is then merely necessary for example, to actuate the locking or latching device provided on the modular unit placed on top, thereby fixedly connecting the two items of furniture to one another. 
   The structure is preferably such that not only similar or functionally identical but, in particular, identical locking base sections are provided on each item of furniture, these being positioned in such a way that, given a corresponding structure, the locking elements provided on the two items of furniture in each case come to lie congruently to one another. Where the structure is identical it is then possible, depending on which locking base section is more easily accessible, to use the latter in turn to carry out the locking with the respective other locking section. The locking is preferably performed simply by pressing in and twisting an actuating part. 
   A bayonet-type locking mechanism is preferably provided. For this purpose, defined projections or depressions are formed on the individual sections and elements which interact with one another in order to produce the desired bayonet-type closure mechanism. Preferably provided locking arms may consist of arms which project radially outwards from a central section of the rotatable locking element. In the case of the basic unit, two diagonally extending locking arms are preferably provided. However, in a preferred development, the locking element is provided with locking arms arranged in a cross shape. This offers the possibility, for example, that the containers to be built one on top of the other can also be mounted on one another in a position in which they have been rotated through 90°, which means that the opening side of a box-shaped container may for example be oriented not only to the front, but also to the left, to the right or to the rear as desired. This does not have a disadvantageous effect on the effectiveness of the locking device. 
   In a particularly preferred embodiment, the individual locking sections are designed in such a way that they correspond to the shape of a through opening in a cup-shaped bottom section of the respective locking element and, in a basic position, come to lie at the level of this through opening. The entire locking base section is thus incorporated securely against rotation in a furniture part. The furniture part equipped with such a locking element is therefore virtually closed in a continuous outer surface, since the locking arms of a locking element come to lie at the level of the through opening, this opening thereby being virtually covered. 
   In an exemplary illustrative non-limiting implementation, provision is also made for a spring device which applies force to the adjustable locking or rotating part in its unlocked basic or starting position. This ensures that the locking arms in their basic or starting position come to lie exactly in the plane of the through opening in the cup-shaped bottom of a locking base section. This also has the advantage that during an unlocking operation—when the locking arms are rotated into the release position, in which position they come to lie congruently to the through opening in the cup-shaped bottom section of a locking base—the corresponding locking element is then lifted into its unlocked position by the spring action. In this position, a further clamping mechanism which then retains the rotating part in this axial position is also provided. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features and advantages will be better and more completely understood by referring to the following detailed description of exemplary non-limiting illustrative implementations in conjunction with the drawings of which: 
       FIG. 1  shows a schematic perspective representation of a furniture system which is composed of a plurality of container elements; 
       FIG. 2  shows a schematic perspective representation of an exemplary illustrative non-limiting first locking element incorporated in a container bottom; 
       FIG. 3  shows a corresponding perspective representation of a second exemplary illustrative non-limiting identical locking device which is incorporated in a top wall of a container furniture item and interacts in the locked state with the first locking device depicted in  FIG. 2 ; 
       FIG. 4  shows a schematic top view of an exemplary illustrative non-limiting locking device; 
       FIG. 5  shows a bottom view of an exemplary illustrative non-limiting locking device; 
       FIG. 6  shows a schematic cross-sectional representation through a locking device; 
       FIG. 7  shows a cross-sectional representation corresponding to  FIG. 6  but in which the cross section runs diagonally through a cross-shaped locking element; 
       FIG. 8  shows a corresponding cross-sectional representation to  FIG. 7 , but in the locking position, in which two locking devices situated in mirror-image form with respect to one another, and thus two bottoms of two items of furniture, are fixed to one another; 
       FIG. 9  shows a schematic perspective representation of an exemplary illustrative non-limiting rotating part having locking arms which are slightly roof-shaped in cross section; 
       FIG. 10  shows a schematic top view of an empty cup- or housing-shaped fixed part having locking depressions in the remaining locking projections so as to achieve a bayonet-type locking mechanism. 
   

   DETAILED DESCRIPTION 
   The schematic perspective representation in  FIG. 1  shows three box- or container-shaped items of furniture  1  which are built one on top of the other and fixed to one another. 
     FIG. 1  shows two items of furniture  1  of relatively large dimensions built one on top of the other, the depth and height of which are dimensioned to be identical, so that the corresponding end face is formed square. The length is twice as long as the height or depth. A locking device  9 , which will be discussed in more detail below, is incorporated in the center of each of the vertical side walls  1   a . The same applies to the opposite vertical side wall  1   b . Locking devices  9  are likewise also incorporated in the lower bottom board  1   c  and the upper top board  1   d , and, since the bottom board  1   c  and the top board  1   d  are twice as large as the end-forming side walls  1   a  and  1   b , provision is made there in each case for two locking devices  9  which are arranged centrally in the transverse direction of the rectangular bottom and top board and thus have a longitudinal space corresponding to half the length of these board-shaped wall elements, the spacing from the center of one locking device  9  to the end of the rectangular bottom being a quarter of the overall length of the board. 
   For the purpose simply of illustrating various possible construction variants,  FIG. 1  also shows a further container element  1 ′ which is built on and mounted at the top, this element having only half the length of the container elements  1  situated below and having only one centrally arranged locking device  9  in the bottom board  1   c  and the top board  1   d  respectively. 
   This very construction shows that in each case the locking device  9  incorporated in a bottom board  1   d  comes to lie, when seen from the top, directly adjacent and congruent to a respective locking device  9  which is provided in an underlying top board  1   d  of an immediately neighbouring box- or container-shaped item of furniture  1 . 
   According to the exemplary embodiment described, all of the stated locking devices  9  are functionally identical and at the same time preferably even identical in design, in which regard two respective locking devices  9  situated in mirror-image form with respect to one another interact and form an exemplary illustrative locking arrangement. 
   Reference will be made in the text below to  FIGS. 2 and 3 ,  FIG. 2  being a schematic perspective representation showing a locking device  9  viewed more or less from the upper side and  FIG. 3  showing a corresponding locking device  9  viewed more or less from the lower side, specifically illustrating how two locking devices  9  interact, for example at the point indicated by “A” in  FIG. 1 , in order to fixedly connect an upper bottom board  1   c  to an underlying top board  1   d  of two furniture containers  1 . As will be further discussed below, when in use not only do the two boards  1   c  and  1   d  then lie against one another along a common add-on plane  11 , but also the two locking devices according to  FIG. 3  and  FIG. 4  touch one another with their bottom faces or are positioned with only a small spacing. In other words, the two locking devices  9  shown in  FIGS. 3 and 4  are brought into contact or direct contact in the add-on direction indicated by the arrow  13 . The stated add-on plane  11  corresponds for example to a horizontal plane.  FIGS. 2 and 3  thus already show that the respectively interacting locking devices  9  have a cup-shaped basic structure, that is to say comprise a cup-shaped fixed part, housing part or base part  15  which has a cup-shaped or cylindrical boundary wall  15   a  and a bottom  15   b.    
   In the exemplary embodiment shown, each locking device  9  additionally comprises a peripheral edge or flange  15   c  which, in the exemplary embodiment shown, comes to lie at the level of the upper cup opening  17 , i.e. opposite the lower bottom  15   b.    
   Each of the locking devices  9  has overall a configuration which deviates from a circular shape in order finally to be able to be incorporated securely against rotation in a shelf board or bottom board. In the exemplary embodiment shown, the cylindrical boundary wall  15   a  of the cup-shaped locking device  9  is not secure against rotation per se. However, the upper flange-shaped edge  15   c  is formed elliptically. An elliptical depression, corresponding to the material thickness of this edge, is made in the respective furniture board  1   c  or  1   d  in addition to a cylindrical bore  19  which passes right through the board, with the result that it is impossible to rotate the locking device  9  after it has been inserted. Otherwise, for example, one or two screws  21  passing through the flange-shaped edge  15   c  could also be screwed into the respective board  1   c  or  1   d  to prevent rotation even with a circular edge or flange  15   c.    
   Moreover, it will also be possible for the cup-shaped design of the base part or fixed part  15  to have, for example at the outer periphery, a configuration which deviates from a cylindrical cross section so as to ensure a rotationally secure fit through a shelf board in a correspondingly fashioned bore  19 . However, this involves more effort. 
     FIG. 4  shows a schematic axial top view and  FIG. 5  shows a schematic axial bottom view of the locking device  9  described. It can be seen from  FIG. 5  that the disc-shaped bottom  15   b  of the locking device  9  has a cross-shaped cutout  23 . In the exemplary embodiment shown, this cutout  23  is of symmetrical design starting from a central axis line  25 , which means that the arm-shaped opening regions  23 ′ emanating radially from the central axis  25  have the same radial length and the same width extending transversely to the radial direction. 
   An adjusting member  29 , which is also sometimes referred to below as a rotating part  29 , is arranged in the cup-shaped interior  27  of each locking device  9 , i.e. in the cup-shaped interior  27  of the base part or fixed part  15  of a respective locking device  9 . This rotating part  29  comprises a cover cap-shaped actuating part  29   a , a driver  29   b  situated below the latter and axially adjoining the actuating part  29   a , and a locking element  29   c  arranged on the underside of the driver  29   b . The aforementioned sections  29   a  to  29   c  of the incision member or rotating part  29  thus formed are fixed in terms of rotation relative to one another. In addition, the rotation part  29  thus formed may be formed in one piece. However, it is also possible for the driver  29   b  to be able to be retracted and extended axially, i.e. telescopically, to a small extent; in other words, the axial length of the driver is adjustable. 
   In the exemplary embodiment shown, the locking element  29   c  comprises four locking arms  31  emanating from the central axis  25 , these arms likewise again being cross-shaped in their configuration and their arrangement, i.e. corresponding in this respect to the cross-shaped cutout  23 . However, the width and length of these locking arms  31  are designed in such a way that their dimensions are correspondingly smaller, with the result that, even in the basic position according to  FIG. 3  or  5 , these locking arms  31  are surrounded by a peripheral gap  33  even if they are arranged at the level of the bottom  15   b  in the cutout  23  situated in the bottom. An overall clearance is thereby achieved, which will be further discussed below. 
   As can be seen from the cross-sectional representations according to  FIG. 6  et seq., there is additionally provided in the interior  34  a spring device  35  which is supported on the one hand on the cup-shaped housing, i.e. on the bottom  15   b  of the base part or fixed part  15 , and on the other hand on the underside of the cover cap-shaped actuating part  29   a . Since the rotating part  29  is held captively in the cup-shaped housing part (also sometimes referred to below as fixed part  5 ), the rotating part  29  cannot be pushed out or fall out of the cup-shaped receiving space  34 . For this purpose, at least two projections, preferably a plurality of projections, which are situated offset from one another in the circumferential direction, or a peripheral closed abutment edge  37  against which the cover cap-shaped actuating part  29   a  would butt, are formed at the level of the flange-shaped edge  15   c . The axial longitudinal extent of the rotatable adjusting member or rotating part  29  is in this case such that, in the basic position according to  FIG. 6 , the arm-shaped and radially projecting locking arms  31  come to lie exactly at the level of the cross-shaped cutout  23  in the bottom  15   b . The spring device  35  mentioned is in this case coordinated in such a way that the prestressing force of the spring exerts adjustment forces on the rotating part  29  in the direction of the upper flange-shaped edge  15   c , but only until the cover cap-shaped actuating part  29  reaches the basic position shown in  FIG. 6 . In this basic position there still remains per se a further axial adjustment travel until the cover cap-shaped actuating part  29   a  abuts against the upper edge  37 . However, in the position shown in  FIG. 6 , the one or more projections  38  (indicated in  FIG. 9 ) formed on the peripheral edge of the cover cap-shaped actuating part  29   a  interacts with the depressions made at corresponding points in the inner wall of the cup-shaped central section of the fixed part  15 . This also results in a pre-adjustment and alignment of the cross-shaped locking arms  31 , since it is precisely in that position that the locking arms  31  can be brought into the same cross-shaped alignment as the cross-shaped cutout  23 . The projections  38  engaging in the depression  43  in the peripheral wall  15   a  of the fixed part  15  in this case additionally produce a certain frictional locking. This also ensures that the spring force of the spring device  35  per se cannot cause the insert part or rotating part  29  to be further adjusted by the force of the spring alone, as is shown in  FIG. 6 . 
   The above-described construction also results in the fact that when correspondingly shaped containers are supplied, the cover cap-shaped cover  29  is situated virtually with a small spacing below the level surface of the outer boundary plane  1   e  of a corresponding wall of the box-shaped container, and also the opposite level surface  1   f  is closed virtually over the whole surface by the bottom and the locking element  29   c  seated in the cutout  23  in the bottom  15   b.    
     FIG. 7  corresponds substantially to the representation according to  FIG. 6 , but with the difference that in  FIG. 7  the rotating part or adjusting member  29  is pressed against the force of the spring energy store device  35  in the direction of the bottom  15   b , with the result that the locking element  29   c  with the mutually opposite locking arms  31  is pressed downward beyond the surface of the bottom  15   b  into that position in which the actual locking is then carried out. Since the sectional representation according to  FIG. 6  and  FIG. 7  is represented diagonally through the cross-shaped locking element  29   c , the overall length of the locking elements  31  can only be seen in  FIG. 7 , not in  FIG. 6 . 
   If two containers are placed one on top of the other in the correct position corresponding to  FIG. 1  and are to be fixed to one another, two locking devices  9  described come to lie directly congruent to one another corresponding to the representation according to  FIG. 8 . Here, the two locking devices  9  which come to lie adjacently are oriented in mirror-image form with respect to their central add-on plane  11 , i.e. with their two bottoms lying on one another. The side on which the bottoms come to lie in each case represents the respective outer side of a corresponding container, with the result that the cover cap-shaped actuating part  29   a  is in each case freely accessible from the inner side of a container. 
   In order to carry out locking of two items of furniture, the freely accessible cover cap-shaped actuating part  29  in one of the two locking devices  9 , for example in the upper locking device  9  in  FIG. 8 , is pressed in against the force of the spring energy store  35 . Since the two cross-shaped locking elements  29   c  of the upper and lower locking devices  9  are situated one on top of the other, pressing in the upper rotating part  29  thus causes the lower locking element  29   c  to be displaced axially downwards, or the locking elements  29   c  belonging to the lower locking device  9  are adjusted by the telescopically retractable and extendable driver unit  29   a  (if such a mechanism is provided) in such a way that the locking element  29   c  connected fixedly in terms of rotation to the upper actuating part  29   a  has its four radially projecting locking arms or fingers  31  situated in the interior  34  of the fixed part  15  situated in the other shelf board, i.e. in the lower shelf board, specifically directly adjacent to the cup-shaped bottom  15   c  of the lower second locking device  9  in  FIG. 8 . If the actuating part  29   a  belonging to the upper locking device  9  is subsequently rotated axially, the locking arms  31  belonging to the upper rotating part  29  are situated behind the remaining locking projections  41 , which are formed by the remaining bottom sections in the bottom  15   b  of the lower locking device  9  in  FIG. 8 . These locking projections  41  are the remaining material sections in the bottom  15   b  which are in each case formed in the direction of rotation about the central axis  25  with a rotational offset with respect to the cross-shaped cutouts  23 . 
   Since, as mentioned, the cutout  23  is designed to be larger in dimension than the locking elements  29   c  which can be moved through it, and also, in the rotating or locking position otherwise, the ends of the locking elements  29   b  terminate with a radial spacing in front of the boundary wall  15   a  of the base part or fixed part  15  interacting therewith, a sufficient compensation margin is ensured in order for example to compensate for tolerance errors when fixedly connecting two containers one on top of the other. 
   It is also preferred for the underside of these locking projections  41  of the bottom  15   b  and/or the adjacent bearing surface of the locking arms  31  to be roof-shaped in cross section, so that with increasing rotating movement from the neutral starting position, an increasingly greater clamping action is produced between the adjusting member  29  of one locking device  9  and the corresponding locking projections  41  in the bottom  15   b  of the respective second locking device  9  interacting therewith. 
     FIG. 9  shows the locking arms  31  which are slightly roof-shaped in cross section or provided with a preferably central, radially extending, slightly rib-shaped elevation  42 , and  FIG. 10  shows a top view of the empty cup-shaped housing or fixed part  15  without inserted adjusting member or rotating part  29 , with the result that the corresponding slightly groove-shaped depression  43  can be discerned particularly clearly here. This affords a bayonet-type locking mechanism, specifically if, in the final locking position, the for example slightly rib-shaped or gable-shaped elevations or projections  42  on a respective locking arm  31  then engage thus in the corresponding depressions  43  on the inner side of the bottom  15   b  of the cup-shaped housing cover  9   a  of the respective second locking device. Since the rotating part is provided with a gripping rib  45  or a gripping projection  45  which assists the rotary movement, it is also possible to tell directly from the orientation of this gripping projection  45  whether a locking engagement has taken place or not. 
   Finally, vertical depressions or vertical projections can also be formed on the inner side of the peripheral wall  15   a  of the cup-shaped housing part  9   a , and these interact with corresponding vertical projections or vertical depressions on the outer periphery of the cover cap-shaped rotating part  29  and thereby also assist the bayonet-type closure mechanism. This also makes it possible for the person carrying out the locking to feel directly when the adjusting member  29  has reached the final locking position. 
   The exemplary embodiment has been described for that case in which the cutout  23  in the bottom  15   c  is cross-shaped and the locking arms  31  are also correspondingly cross-shaped. However, it would also be conceivable in principle for the cutouts as well as the locking arms to have only a diagonal shape or bar shape. 
   It is also possible for the spiral spring device  35  described to be replaced by elastically deformable internal plastic arms cast integrally with the cup-shaped housing part  15 , which is preferably formed from plastic, these plastic arms exerting the desired prestressing forces on the adjusting member  29 . 
   An unlocking operation can again be carried out just as simply as the locking operation. Precisely that rotating part  29  which has been used for the locking operation is now once more turned back or rotated further until the locking arms  31  come to lie in the correct position with respect to the cross-shaped through opening  23  in the two bottoms  15   b  situated one on top of the other. The assistance provided by the spring energy store then moves the pressed-in rotating part back again into its raised position in  FIG. 6 . 
   The roof-shaped run-on surfaces on the locking arms  31  or otherwise obliquely formed or wedge-shaped run-on surfaces make it possible, with increasing rotating movement, to produce increasingly greater clamping forces directed axially towards one another between the two interacting locking devices  9 . Each of the two locking devices  9  is in this case firmly anchored on the associated item of furniture, for example on a bottom board  1   c  and a top board  1   c  situated below the latter. Since the flange-shaped peripheral edge  15   c  in each case comes to lie on the opposite inner side of the container, none of the two locking devices can be removed from its bore in the associated shelf board even when locking forces are to be directed towards one another with ever increasing intensity. Each of the two locking devices  9  is in this case held on the associated shelf board by the flange-shaped edge. 
   While the technology herein has been described in connection with exemplary illustrative non-limiting implementations, the invention is not to be limited by the disclosure. The invention is intended to be defined by the claims and to cover all corresponding and equivalent arrangements whether or not specifically disclosed herein.

Technology Classification (CPC): 5