Abstract:
A latching device for at least two housing parts, in which a snap-on connection as well as a latching connection between the housing parts is produced by a correspondingly designed rotary knob/pushbutton function. The actuating button preferably is respectively arranged on two opposing sidewalls of an upper housing part, wherein the actuating button respectively acts upon a spring lever that is arranged on the inner wall of the upper housing part. 
     During assembly of the upper housing part and a lower housing part, a forced snap-on connection between the two housing parts is produced and can only be disengaged again by exerting pressure upon the actuating buttons on both sides.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to a latching device for an at least two-part housing that features an upper housing part with sidewalls and a corresponding suitable lower housing part. 
     A latching device of this type is required for selectively holding together two housing halves in a snap-on or a latching fashion and for once again separating said housing halves, wherein a function that is not dependent on external environmental influences needs to be ensured. 
     2. Description of the Related Art 
     EP 1 046 769 B1 discloses a pivoting lever closure with a push-button latch for the pivoting lever that is designed for locking switchgear cabinet doors or the like. 
     SUMMARY OF THE INVENTION 
     The invention therefore is based on the objective of designing an internal latching device for a two-part housing that is protected from function-impairing environmental influences, wherein it is possible to optically determine from the outside whether the latching device is effective, and wherein the latching device furthermore features a locking function against unauthorized access. 
     This objective is attained in that an externally operated actuating button is respectively arranged within circular integral structures on at least one of two opposing sidewalls of the upper housing part, in that the actuating button is engaged with a spring lever that is arranged in the interior of the upper housing part, in that the actuating button is realized in the form of a combined rotary knob/pushbutton, and in that the spring lever produces a snap-on connection or a latching connection between the two housing parts in dependence on the position of the actuating button. 
     The invention concerns a latching device for separably contacting an upper housing part to a lower housing part, wherein the latching device makes it possible to selectively snap together the two housings or to connect the two housings by means of another selectable latching mechanism. 
     The mechanism for the latching device is integrated into at least one housing wall within one housing half, namely the upper housing part, such that environmental influences are advantageously rendered irrelevant. In addition, no significantly protruding integral elements are required externally. 
     In this case, only three moving parts are provided in the upper housing part: an actuating button with a seal and a spring lever. The lower housing part, in contrast, is merely provided with an integral element in the form of a snap-on tab for snapping together the housing parts. 
     The advantages attained with the invention can be seen, in particular, in that the housing halves are initially snapped together automatically with the aid of the latching device during the assembly, and in that the housing halves can only be unlatched again by exerting pressure upon an actuating button that is respectively arranged on two opposing sides of the upper housing part. 
     In addition, the two housing halves can be advantageously latched together, wherein this latching becomes effective when the actuating button is turned about its axis by 90° after the latching device is engaged such that the simple removal of the upper housing part is initially prevented at least without a tool. 
     In the region of the actuating button, the upper housing part is sealed against environmental influences by means of a ring seal. 
     In this case, the seal contains a color marking and is arranged on the actuating button in such a way that the unlatched state is optically indicated by the color marking in the unlatched state, in which the actuating button slightly protrudes from the housing. Once the actuating button is latched, the seal also is no longer visible. 
     The actuating button is engaged with the spring lever arranged in the interior of the housing. The spring lever consists of an elongated spring-elastic material and is respectively arranged on the inner side of the upper housing part. In this case, the spring lever is movably fixed in the upper housing part in a recess in the respective sidewall by means of two angular holding brackets, wherein the other end of the spring lever features an opening for producing a snap-on connection with a tab on the lower housing part. Another opening is arranged in the spring lever about centrally, wherein an integral shaft of the actuating button extends through said opening. 
     An integral toggle is provided on the shaft of the actuating button and adjoins the central opening of the spring lever while the other side of the spring lever is provided with a locking hook that is arranged on the end of the shaft and serves for controlling the spring lever by means of the actuating button. 
     The two housing halves are automatically snapped together during the assembly. The snap-on opening in the spring lever is only disengaged from the snap-on hook in the lower housing part in order to remove the upper housing part by exerting pressure upon two actuating buttons that are preferably arranged on opposing sidewalls of the upper housing part. In order to additionally latch the housing parts, the actuating button needs to be turned by 90°, wherein this actuating button fixes the spring lever on the snap-on hook in such a way that the upper housing part cannot be removed by means of a specially designed mechanical device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One embodiment of the invention is illustrated in the figures and described in greater detail below. The figures show: 
         FIG. 1   a  an upper housing part; 
         FIG. 1   b  a lower housing part that is suitable for the upper housing part; 
         FIG. 2  an actuating button; 
         FIG. 3  a ring seal; 
         FIG. 4  a spring lever; 
         FIG. 5  the function of the latching device when snapping together the attached upper and lower housing parts; 
         FIG. 6  the function of the latching device when latching an upper housing part to a lower housing part; 
         FIG. 7  the function of latching two housings; 
         FIG. 8  the mechanism for controlling the latching connection and the snap-on connection, and 
         FIG. 9  a tool opening provided in the actuating button. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1   a  shows an upper housing part  1  that is suitably shaped for accommodating a latching device with an actuating button  20  in two opposing sidewalls  2 , as well as a suitable lower housing part  5 . 
     It should be noted that a cover of the upper housing part  1  with a cable in-feed arranged therein is not illustrated in greater detail in this figure. 
     With respect to the frame-shaped lower housing part  5  according to  FIG. 1   b  that is designed for being rigidly screwed over a wall opening and surrounded by a flange  9  for this purpose, the only relevant components are an integral snap-on tab  6  on an inner sidewall  7 , as well as a guide rail  8  that is arranged to the left and to the right thereof and spaced apart therefrom. 
     The upper housing part  1  features integral structures with an outwardly curved, circular outer bead  10  and a second, smaller circular bead  11  that is arranged within the outer bead. 
     In this case, a few special integral structures including a slot-shaped opening  12  with a central circular opening  13  are provided within the second inner bead  11 , wherein the function of these special structures is explained further below. 
       FIG. 2  shows the actuating button  20  with a flat thrust washer  21  and an integral pin-shaped structure with different contours for controlling the movement and the locking of the actuating button. 
     A collar  22  with a peripheral groove  23  is initially attached to the thrust washer  21 , and the collar  22  in turn features an integral shaft  25  with a toggle  26  and a locking hook  27  on the end of the shaft. 
     The face of the collar  22  referred to the shaft  25  features an elevated X-shaped locking structure  24 , the importance of which is explained further below. 
       FIG. 3  shows a ring seal  30  that is arranged between the actuating button  20  and the upper housing part  1 . 
     The ring seal  30  has a U-shaped cross sectional structure that forms a double lip with an inner lip  33  and an outer lip  32  and is provided with a central circular opening  31 , wherein said ring seal is arranged on the sidewall  2  within the first bead  10  and seals the actuating button  20  relative to the upper housing part  1 . 
       FIG. 4  shows a spring lever  40  that is responsible for the snap-on and latching functions together with the actuating button  20 . The spring lever is realized in the form of an elongated, strip-shaped stamping of spring-elastic material. 
     In this case, a U-shaped angular holding bracket  41  that is angled relative to the stamping is provided on the upper end in this figure while the opposite end contains a slightly angled bend  44 . 
     A keyhole opening  42  and a rectangular snap-on opening  43  are stamped into the central straight region of the spring lever. 
     In this case, the keyhole opening  42  is provided for leading through the shaft  25  of the actuating button  20 , wherein the spring lever  40  is held between the toggle  26  and the locking hook  27  of the actuating button  20  while the rectangular snap-on opening  43  is provided for being snapped together with the snap-on tab  7  on the lower housing part  5 . The spring lever is guided within the upper housing part in two integral vertical guide rails  3 . 
       FIG. 5  shows an upper housing part  1  that is snapped together with the lower housing part  5  in the form of a sectional representation. 
     During the assembly of the two housing parts, the snap-on effect of the latching unit is immediately realized in that a snap-on tab  7  on the lower housing part  5  engages into a snap-on opening  43  of the spring lever  40 . This figure shows a section through the center of both beads  10 ,  11  in one of the sidewalls  2  of the upper housing part  1 . 
     Consequently, the actuating button  20  with its thrust washer  21  is still arranged outside the first outer bead  10 . 
     The ring seal  30  is fixed on the integral structure of the collar  22 , wherein said ring seal contains an integral elevated collar  34  that is arranged on the inner lip  33  forming the circular opening  31  and engages into the annular groove  23  provided in the collar  22 . In addition, the shaft  25  extends through the slot-shaped and circular openings  12 ,  13  of the housing wall  2 , as well as the keyhole opening  42  of the spring lever  40 , wherein the spring lever  40  is held in a movable yet guided fashion on the end of the shaft  25  between the toggle  26  and the locking hook  27 . 
       FIG. 6  shows an upper housing part  1  that is attached to the lower housing part  5 . 
     In this case, the actuating button  20  is pulled into the first outer bead  10  because the sidewall  6  of the lower housing part  5  is pushed between the sidewall  2  of the upper housing part  1  and the bend  44  of the spring lever  40 , wherein the angular holding bracket  41  is supported within a recess  14  in the sidewall  2  of the upper housing part  1  and the spring lever  40  is aligned almost vertically between the lateral sections of the groove  14  and thusly pulls the actuating button  20  toward the housing. 
     If pressure is exerted upon the actuating button  20  in the position illustrated in  FIG. 6 , the spring lever  40  is also pressed inward by means of the toggle  26  such that the snap-on opening  43  releases the snap-on tab  7  and the housings  1  and  5  can be separated from one another. 
     This process is illustrated in  FIG. 7 . Although the two housing halves are already separated from one another in this case, the actuating button is still situated within the outer bead  10  such that the spring lever  40  and is pressed inward by means of the toggle  26  and thusly causes the snap-on opening  43  to be released from the snap-on tab  7 . 
     The above-indicated structures in the sidewall  2 , within the inner bead  11  and the actuating button  20  are responsible for latching together the two housings  1 ,  5  as explained below with reference to  FIG. 8 . 
     The slot-shaped opening  12  with the central circular opening  13  is provided in the center of the inner bead  11 . 
     In addition, the center of the inner bead  11  features a peculiarity in the form of a cruciform structure that is defined by three planes, wherein an elevated X-shaped cross that consists of non-connected cross arms and resembles an Andrews cross initially defines a first outer plane  17  that is followed by a central plane  18  between the cross arms that is aligned vertically in this case and a third lower plane  19  in an extension of the slot-shaped opening  12  that is aligned horizontally between the cross arms in this case. 
     The actuating button  20  equivalently features a shaft  25  with a toggle  26  that can be inserted into the slot-shaped opening  12  of the inner bead  11  such that the toggle  26  is latched behind the sidewall  2  when the actuating button  20  is subsequently turned by 90°, namely due to the fact that the X-shaped locking contour  24  on the collar  22  of the actuating button  20  is pulled inward up to the third lower plane  19  that represents the laterally reversed negative of the X-shaped locking contour  24 , and initially prevented from being additionally turned. During this process, the spring lever  40  is simultaneously latched by means of the locking hook  27  such that the upper housing part  1  is latched to the lower housing part  5 . 
     In the unlatched state of the actuating button  20 , part of the colored ring seal  30  in the form of a collar is visible as a status indicator. In the latched state, the actuating button  20  with the ring seal  30  is displaced into the outer bead  10  of the housing such that the colored collar is no longer visible. 
     According to another characteristic, accidental or unauthorized unlatching of the actuating button  20  can be prevented, wherein a tool opening  29  that is designed for a hexagonal wrench in this case, but may also have any other shape, is provided on the thrust washer  21  of the actuating button for this purpose—as shown in  FIG. 9 . Furthermore, a position indicator  28  provided on the thrust washer respectively indicates the snap-on and latching status, wherein the vertical position shown indicates that the two housing halves are merely snapped together.