Abstract:
The invention is directed to a housing, in particular for an electric appliance, having a housing part ( 1 ) with a noncircular cross section closed by a detachable housing bottom ( 3 ). The housing bottom ( 3 ) includes an outer bottom ( 4 ) and an inner bottom ( 5 ) mounted for rotation in the outer bottom ( 4 ). In a closed condition, the inner bottom ( 5 ), the housing part ( 1 ) and the outer bottom ( 4 ) are joined together in particular by positive engagement.

Description:
This is a continuation of International Application PCT/EP98/03886, co-pending, with an International filing date of Jun. 25, 1998. 
    
    
     This invention relates to a housing, in particular for an electric appliance, having a housing part with a noncircular cross section closed by a detachable housing bottom. 
     Cylindrical housing parts closed by a circular housing bottom with a thread or the like are already known. To open the housing part the housing bottom is first transferred into an open state by the user turning it and is then removed from the housing part. In the case of an electric appliance, for example, the user can then replace empty batteries. 
     In the case of noncircular housing parts, other devices are known with which the likewise noncircular housing bottom is detachably fastened to the housing part. For example, the housing bottom can be inserted in the housing part and locked there. Inserting and locking the housing bottom in this way is often associated with difficulties for the user, particularly when compared to the simple operation of screwing the housing bottom in and out as described above. 
     SUMMARY OF THE INVENTION 
     Proceeding from this realization, it is an object of the present invention to provide a housing with a noncircular housing part, having a housing bottom which is easy to open and close by a user. 
     In a housing of the type initially referred to, this object is accomplished in accordance with the invention in that the housing bottom is comprised of an outer bottom and an inner bottom rotatably mounted in the outer bottom. 
     With the aid of the rotatable inner bottom the housing bottom can be opened and closed by the user in simple manner. The complicated insertion of the housing bottom in the housing part is unnecessary. Thanks to the invention the user is thus able to handle the noncircular housing bottom in the same way in which he is accustomed with a circular housing bottom. The opening and closing of the housing part to replace batteries, for example, is thus made far simpler and hence easier for the user. 
     In an advantageous further aspect of the invention, the outer contour of the outer bottom has roughly the inner contour of the housing part&#39;s noncircular cross section. The outer bottom forming an outer surface of the housing has the job of covering that opening in the housing part which needs to be closed. It is not the job of the outer bottom to lock with the housing part or to turn. Hence the outer bottom can be particularly well adapted to the housing part. 
     In a further advantageous configuration of the invention the outer bottom has a circular opening into which the inner bottom extends, and the outer contour of the inner bottom has roughly the inner contour of the circular opening in the outer bottom. Hence the opening in the outer bottom is filled by the inner bottom. On the whole, the outer surface in the area of the housing bottom is thus formed by the outer bottom and the emerging projection of the inner bottom. In this emerging projection the inner bottom is provided, for example, with a slot or the like. This slot enables the user to turn the inner bottom in simple manner, transferring the entire housing bottom from a closed state into an open state. 
     In an advantageous embodiment of the invention in the closed state the inner bottom, the housing part and the outer bottom are joined together in particular by positive engagement. This represents a simple but secure way to fasten the housing bottom in the housing part. Said closed state can be effected by the user turning the inner bottom and thus establishing the positive engagement relationship. In the open state there is no positive engagement, making it possible for the housing bottom to be removed from the housing part. 
     Particularly conveniently, the inner bottom has at least one arm which cooperates with a cutout or the like in the interior of the housing part into which the arm engages in the closed state, and furthermore the inner bottom has at least one arm which cooperates with a frame or the like on the outer bottom into which the arm engages in the closed state. These arrangements can be implemented in the design in simple manner yet guarantee a secure positive engagement relationship and hence a durable fastening of the housing bottom in the housing part. 
     In an advantageous further aspect of the invention the inner bottom, in particular at least one of the arms of the inner bottom, and the housing part are equipped with locking means, particularly with a nose and a cooperating groove. Locking of the inner bottom in the closed state is thus achieved in simple manner. Consequently, the inner bottom is unable to turn by itself into the open state, and the housing bottom is hence unable to detach itself from the housing part without the user&#39;s intervention. 
     In yet another advantageous aspect of the invention a seal is positioned between the housing part and the outer bottom and/or a seal is placed between the outer bottom and the inner bottom. These seals, preferably made of an elastomer material, prevent the ingress of water and/or dirt into the interior of the housing. Suitably, the seals can either be inserted between the components identified or be fitted to at least one of said components in a two-component injection molding process. 
     In this arrangement it proves an advantage for at least one of the seals to be joined to the housing part and/or to the outer bottom and/or to the inner bottom in a two-component injection molding process. 
     Finally, there is the advantageous possibility of covering cutouts in the housing part from the outside by a layer of elastomer, the layer being joined to the housing part in a two-component injection molding process. 
     Further features, application possibilities and advantages of the present invention will become apparent from the subsequent description of embodiments of the present invention illustrated in the Figures of the accompanying drawing. It will be understood that any single feature and any combination of single features described or represented by illustration form the subject-matter of the present invention, irrespective of their summary in the patent claims or their back-reference, as well as irrespective of their wording and representation in the description and the drawing, respectively. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic top plan view of a housing bottom of an embodiment of a housing of the present invention; 
     FIG. 2 is a schematic longitudinal sectional view of the e housing of FIG. 1, taken along the plane II—II of FIG. 4; 
     FIG. 3 is a schematic longitudinal sectional view of the housing of FIG. 1, taken along the plane III—III of FIG. 2; 
     FIG. 4 is a schematic cross-sectional view of the housing of FIG. 1, taken along the plane IV—IV of FIG. 2; 
     FIG. 5 is a schematic sectional view of the housing of FIG. 1, taken along the plane V—V of FIG. 4; 
     FIG. 6 is a schematic sectional view of the housing of FIG. 1, taken along the plane VI—VI of FIG. 4; and 
     FIG. 7 is a schematic cross-sectional view of the housing of FIG. 1 in accordance with FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 to  7  show a housing part  1  of a housing intended for use in particular as the housing of an electric appliance. The housing part  1  (housing piston) is shaped like a cylinder but has a noncircular cross section. The housing part  1  is intended, for example, to accommodate one or more batteries, which are then arranged in longitudinal direction inside the housing part  1 . 
     At its free end the housing part  1  has an opening  2  with an approximately oval inner contour filled by a housing bottom  3 . It will be understood, of course, that the inner contour of the opening  2  does not have to be a regular oval but can be any shape, including asymmetrical. The housing bottom  3  is arranged approximately transverse to the longitudinal direction and is detachably connected to the housing part  1 . In a closed state the housing bottom  3  covers the opening  2  in the housing part  1 , thus closing the housing part  1 . In an open state the housing bottom  3  can be removed from the housing part  1  in particular with the aid of a helical compression spring or the like. The interior of the housing part  1  is thus accessible and it is possible to take out the batteries, for example, accommodated inside. 
     The housing bottom  3  has an outer bottom  4  (outer wall section) and an inner bottom  5  (inner wall section). The outer bottom  4  is arranged so as to be approximately flush with the free end of the housing part  1 , forming an outer surface of the housing part  1  and the housing. The inner bottom  5  is positioned on that side of the housing part  1  facing the interior. 
     The outer contour of the outer bottom  4  is of an approximately oval configuration corresponding essentially to the oval inner contour of the opening  2 . Disposed between the outer bottom  4  and the housing part  1  is an elastomer seal  6  which either is inserted between the components identified or is molded to one said components by a two-component injection molding process. 
     The outer bottom  4  has a circular opening  7  at roughly the point of intersection of the longest and the shortest dimension of the approximately oval area formed by the outer bottom  4 . The inner bottom  5  extends with a circular projection  8  into this opening  7 . The outer contour of the projection  8  essentially matches the inner contour of the opening  7 . Arranged between the outer bottom  4  and the projection  8  of the inner bottom  5  is an elastomer seal  9  which either is inserted between the components identified or is molded to one of said components by a two-component injection molding process. 
     The inner bottom  5  is rotatably mounted with its projection  8  in the opening  7  and hence in the outer bottom  4 . The axis of rotation is arranged approximately parallel to the longitudinal direction of the housing part  1 . The outer bottom  4  is displaceable together with the inner bottom  5  in longitudinal direction inside the housing part  1 . In particular it is possible for the outer bottom  4  to be detached together with the inner bottom  5  from the housing part  1  for removal. Similarly, the inner bottom  5  with its projection  8  is displaceable in longitudinal direction in the opening  7  of the outer bottom  4 . 
     The inner bottom  5  has two arms  10  that are arranged approximately transverse to the longitudinal direction of the housing part  1  and in approximately opposite directions and which extend towards those inner walls of the housing part  1  that are spaced a smaller relative distance. These inner walls contain two cutouts  11  extending to the outside and cooperating with the two arms  10 . The arms  10  and the cutouts  11  are constructed so that in the closed state each of the arms  10  engages in its corresponding cutout  11 , establishing a positive engagement relationship therewith. In this way the inner bottom  5  is securely connected to the housing part  1  in the closed state. 
     In addition to this, the inner bottom has two arms  12  that are arranged approximately transverse to the longitudinal direction of the housing part  1  and in approximately opposite directions and which extend towards those inner walls of the housing part  1  that are spaced a greater relative distance. Projecting into the interior of the housing part  1  from the outer bottom  4  are two essentially U-shaped frames  13  which cooperate with the two arms  12 . The arms  12  and the frames  13  are constructed so that in the closed state each of the arms  12  engages in its corresponding frame  13 , establishing a positive-engagement relationship therewith. In this way the outer bottom  4  is securely connected to the inner bottom  5  and hence similarly securely to the housing part  1  in the closed state. 
     The four arms  10  and  12  are arranged in alternation at an angle of about 90 degrees to each other. The respective cutouts  11  and frames  13  are constructed so that the arms  10 ,  12  can pass from the described closed state into the open state. In the open state the arms  10  lie outside the cutouts  11  and the arms  12  lie outside the frames  13 . The closed state is shown in particular in FIG.  4  and the open state in FIG.  7 . 
     A slot  14  is formed on the outside of the projection  8  of the inner bottom  5  emerging through the opening  7 . A coin or the like can be inserted in this slot  14  and be used to turn the inner bottom  5  through an angle of about 45 degrees from the open state into the closed state and vice versa. It will be appreciated that profiles of some other shape can also be used instead of the slot  14 . 
     One of the arms  10  of the inner bottom  5  is provided with a nose  15  for cooperation with a groove  16  provided in the corresponding cutout  11  of the housing part  1 . In the closed state the nose  15  engages in the groove  16 . The inner bottom  5  is thus locked in the closed state. It will be understood, of course, that it is also possible for both arms  10  to be equipped with such noses  15  and corresponding grooves  16  and/or for the arms  12  and frames  13  to be equipped with locking means of this type. 
     On the outside of the housing part  1  the cutouts  11  are covered with an elastomer layer  17  which is joined to the housing part  1  in a two-component injection molding process, for example. The elastomer layer  17  improves the grip of the housing part  1 . It will be understood that it is also possible to substitute outwardly closed recesses in the inner wall of the housing part  1  for the cutouts  11 .