Patent Publication Number: US-9431191-B2

Title: Position switch

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to DE 10 2013 019 597.7, filed Nov. 25, 2013, the complete disclosure of which is herein incorporated by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a position switch according to the preamble of Claim  1 . 
     BACKGROUND OF THE INVENTION 
     DE 602 23 640 T2 discloses a position switch which has a housing in which a device that is able to move translationally and an electric switch assembly that is actuable by this device are arranged. A manoeuvre head is fitted so that it is removable and angularly variable in a recess of the housing, said recess opening out onto a fitting surface of the housing. For this purpose, the manoeuvre head has a tubular bearing surface which houses a push button which is actuated directly or indirectly by an object and is able to slide along the translation axis in order to interact with the movable device. 
     It is known here that it is often desirable to be able to adjust the position of the manoeuvre head of such a switch. Such adjustment may be necessary for example when it is desired to mount the switch in a predetermined position. For this purpose, the manoeuvre head has an external toothing with outer notches which interact with inner notches of an internal toothing which is provided in the recess in the housing or the opening of the housing. The inner notches can be provided at the same intervals or at multiple intervals with respect to the external toothing, in order to increase the diversity of uses. 
     In the case of a position switch known from JP H11-167 844 A, a pivoting lever is fixable in different angular positions on a shaft of the position switch by means of a crown toothing. Finally, DE 20 36 853 A furthermore discloses to fix housings of signalling devices so as to be settable at any desired angle to one another by means of a crown toothing. 
     However, it is a disadvantage that toothings having an external and an internal toothing demand flawless pairings, with the result that the design is complex. This is the case in particular when an angular and rotationally locked assignment of actuating head and housing to one another shall be possible in the entire pivoting range of preferably 360° in selectable steps in accordance with the tooth pitch. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the invention to provide a position switch of the stated type, which allows improved arranging and blocking of the actuating head on the housing in correct angular positions. 
     This object is achieved by the features of Claim  1 . 
     Hereby a position switch is provided in which the actuating head can be positioned and blocked via an axially effective, planar surface toothing on the switch housing. Here, the teeth mesh with one another in a planar manner in the sense of a form-fitting, releasable coupling. The teeth are arranged radially and position the actuating head with respect to the switch housing. The number of teeth arranged in a circumferentially distributed manner is selectable. The full force-locking connection can be achieved by an axial bracing of the plug-in toothing. 
     Thus, according to the invention an end toothing is provided which can absorb more force on account of the fact that the teeth of a first planar toothing have a greater radial extent than the teeth of a second planar toothing. The tooth flanks of the teeth of the first planar toothing provide bearing surfaces which provide a secure force-locking and form-locking connection of a toothing of compact design by way of a radial oversize with respect to the second planar toothing. Preferably, the radial oversize is limited to an outer thickness portion of the tooth-head. As a result, the tooth root is enlarged with respect to the tooth head. The teeth of the second planar toothing are then quasi embedded between the teeth of the first planar toothing. 
     The first planar toothing can be provided on the actuating head or on a switch head being provided on the switch housing. The second planar toothing is then provided on the other component in each case. 
     For an axial bracing of the toothing, a sleeve-like extension, which is lockable to the switch housing via a locking plate when the toothing is axially effective, can be provided on the actuating head. 
     Further configurations of the invention can be gathered from the following description and the dependent claims. 
     The invention is explained in more detail hereinafter with reference to the exemplary embodiment illustrated in the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows an exploded view of an actuating head with a pivoting-lever actuator and a switch head of a position switch, 
         FIG. 2  shows a perspective view of the individual parts according to  FIG. 1  in the assembled state, 
         FIG. 3  shows an enlarged illustration of the detail A according to  FIG. 2 , 
         FIG. 4  shows an enlarged illustration of the switch head according to  FIG. 2 . 
     
    
    
     DESCRIPTION OF THE SPECIFIC EMBODIMENTS 
     The invention relates to a position switch. The position switch comprises, in a known manner, an actuator  1  having an actuating head  2  and a switching element (not illustrated) contained in a housing. In order to configure the position switch with a safety function, the connection between the actuator  1  and the switching element should be made in a rigid manner. The switching element has a plunger (not illustrated) on which the actuator  1  acts. Usually, when the position switch is actuated, the plunger of the switching element is pushed downwards, i.e. a translatory movement is carried out. 
     As shown in  FIG. 1  and  FIG. 2 , the position switch comprises a pivoting-lever actuator  3  which has a switching shaft  4  supported in the actuating head  2 , said switching shaft  4  switching an actuating element  5  in order to move the plunger of the switching element of a switch which is arranged in the switch housing and has for example normally closed and/or normally open contacts (not illustrated). According to  FIG. 1 , the actuating element  5  is, for example, a pressure plate which slides along the translation axis X upon actuation. 
     The pivoting-lever actuator  3  comprises a lever  6  which is fastenable to the switching shaft  4  via a connection ring  7 , for example by means of a screw  8 . In a conventional manner, the lever  6  carries on its free end a roller  9 , which is hit by an object (not illustrated) which actuates the position switch. In an alternative exemplary embodiment which is not illustrated, the lever  6  can be reduced to the roller  9 . 
     The actuating head  2  preferably is generally L-shaped, the one limb  10  of which accommodates the switching shaft  4  in a rotatable manner and the other limb  11  of which accommodates the pressure plate  5  with a press-in disc  12  and a pretensioning spring  13 . At its lower end, the limb  11  narrows to form a tubular extension  14  which is inserted into a cutout  15  in a switch head  16  during assembly. 
     The switch head  16  is intended to be fastened to the switch housing (not illustrated). The actuating head  2  is fixable in a locking manner to the switch head  16  in different angular positions, for which purpose the actuating head  2  is connectable to the switch head  16  via a plug-in toothing  17  (cf.  FIG. 2 ). 
     According to the invention, the plug-in toothing  17  is provided as follows. The switch head  16  and the actuating head  2  have crown toothings  18 ,  19  which are fittable axially into one another and the teeth  20 ,  21  of which that are arranged circumferentially in a manner spaced apart from one another provide first and second planar toothings  22 ,  23 . The teeth  20  of the first planar toothing  22  have tooth flanks  24  that have a greater radial extent  25  than the teeth  21  of the second planar toothing  23 . According to the exemplary embodiment illustrated, the first planar toothing  22  is provided preferably on the switch head  16 . According to an alternative exemplary embodiment that is not illustrated, the first planar toothing can be provided on the actuating head  2 . 
     The first and second planar toothings  22 ,  23  are preferably arranged as crown toothings on the switch head  16  and the actuating head  2 , respectively, with radially extending teeth  20 ,  21 . The teeth  20 ,  21  being circumferential segments that are arranged in a spaced-apart manner can have a parallel-faced or pointed tooth shape. 
     As is shown in particular in  FIG. 1 , the actuating head  2  preferably has the crown toothing  19  at the point at which the extension  14  adjoins the limb  11 . In order that the crown toothing  19  forms an end toothing, the extension  14  has a smaller diameter than the limb  11 . 
     The crown toothing  19  is thus provided in an annular manner at the transition region from the limb  11  to the extension  14 . The switch head  16  provides the crown toothing  18  on the head side above the opening of the cutout  15 . 
     As is shown in particular in  FIG. 3 , the radially extending tooth flanks  24  of the respective first planar toothing  22  preferably have a trapezoidal shape. The radially extending tooth flanks  26  of the respective second planar toothing  23  preferably have a rectangular shape. The greater radial extent of the teeth  20  of the respective first planar toothing  22  is preferably provided as a root-side widening. This is illustrated in particular in  FIG. 3 .  FIG. 3  further illustrates that such a radial extension of the teeth of the respective first planar toothing  22  with respect to the translation axis X in conjunction with a bevelled outer tooth side  29  allows the first planar toothing  22  to be attached to the actuating head  2  in a base-like manner. 
     Preferably, the first planar toothing  22  is positioned in a manner offset radially towards the outside with respect to an inner circumferential contact area  27 . This contact area  27  is preferably assigned to a radial spacer ring  28  on which the second planar toothing  23  is then preferably arranged. The spacer ring  28  can define a coupling depth of the plug-in toothing  17  with respect to the contact area  27 . For an axial force-locking connection of the plug-in toothing  17 , it is then not necessary for the tooth heads of the teeth  20 ,  21  each to be in contact with the respective other planar toothing  22 ,  23 . The form-locking connection achieved by the teeth  20 ,  21  is sufficient. 
     For an axial bracing of the plug-in toothing  17  a locking plate  30  is provided, for example, which is insertable into a recess  31  in the switch head  16  and comes into engagement with an engagement groove  32  on the extension  14  of the actuating head  2 .