Explosion-proof cross-type limit switch
A cross-type limit switch ( 10 ) with a housing ( 12 ) that contains a gear mechanism ( 24 ) that includes a cover plate ( 38 ), base plate ( 48 ), and intermediate plate ( 42 ). The intermediate plate ( 42 ) has first and second cutouts ( 44, 46 ) within which respective gearwheels ( 54, 58 ) are arranged. The first and second gear wheels ( 54, 58 ) have respective plugthrough openings ( 56, 60 ), and a shaft ( 20 ) coupled to an actuating lever ( 18 ) outside the housing is rotatably mounted in a first bearing arrangement ( 22 ) connected to the housing. The actuating lever shaft ( 20 ) extends through the first plugthrough opening ( 56 ) of the first gear wheel ( 54 ) for rotating and radially locating the first gear wheel ( 54 ). A rotary switch ( 30 ) arranged in the housing ( 12 ) has a switch shaft ( 138 ) rotatably mounted in a second bearing arrangement ( 106, 34 ) that extend through the second plugthrough opening ( 60 ) of the second gearwheel for rotating and radially locating the second gearwheel ( 58 ).
1. An explosion-proof limit switch ( 10 ) comprising:
a housing ( 12 );
a gear mechanism ( 24 ) arranged in said housing ( 12 ), said gear mechanism including a gear mechanism cover plate ( 38 ), a gear mechanism base plate ( 48 ) and at least one intermediate plate ( 42 ) arranged between the gear mechanism cover plate ( 38 ) and the gear mechanism base plate ( 48 );
said intermediate plate ( 42 ) having at least one cutout ( 44 ) in which a first gearwheel ( 54 ) is arranged and at least one second cutout ( 46 ) in which a second gearwheel ( 58 ) is arranged;
said first gearwheel ( 54 ) having a first plug-through opening ( 56 ) and said second gearwheel ( 58 ) having a second plug-through opening ( 60 );
a shaft ( 20 ) having an actuating lever ( 18 ) arranged outside the housing ( 12 ) and being rotatably supported in a first bearing arrangement ( 22 ) connected to the housing ( 12 ) and extending through the first plug-through opening ( 56 ) of the first gearwheel ( 54 ) in order to couple with the first gearwheel ( 54 ) in a torque transmitting manner and to radially support said first gearwheel ( 54 ); and
a rotary switch ( 30 ) arranged in the housing ( 12 ) and having a switch shaft ( 138 ) that is rotatably supported in a second bearing arrangement ( 106 , 134 ) and extends through the second plug-through opening ( 60 ) of the second gearwheel ( 58 ) in order to couple with the second gearwheel ( 58 ) in a torque transmitting manner and to radially support said second gearwheel ( 58 ).
2. The explosion-proof limit switch ( 10 ) of claim 1 in which said first gearwheel ( 54 ) and said second gearwheel ( 58 ) are arranged with play in the respective first and second cutouts ( 44 , 46 ).
3. The explosion-proof limit switch ( 10 ) of claim 2 in which the play between said first and second gearwheels ( 54 , 58 ) and the respective first and second cutouts ( 44 , 46 ) is greater than any radial bearing play of the shaft ( 20 ) of the actuating lever ( 14 ) or the switch shaft ( 138 ) of the rotary switch ( 30 ).
4. The explosion-proof limit switch ( 10 ) of claim 2 in which said shaft ( 20 ) of the actuating lever ( 18 ) has an end face formed with a bezel ( 166 ) or rounding, and the play of the first and second gearwheels ( 54 , 58 ) and the respective first and second cutouts ( 44 , 46 ) is smaller than the bezel ( 166 ) or rounding of the shaft end face ( 164 ).
5. The explosion-proof limit switch ( 10 ) of claim 1 in which said first cutout ( 44 ) encloses said first gearwheel ( 54 ) and said second cutout ( 46 ) encloses said second gearwheel ( 58 ).
6. The explosion-proof limit switch ( 10 ) of claim 1 in which said first cutout ( 44 ) and said second cutout ( 46 ) form passage openings ( 44 ) with walls ( 70 , 72 ) that are parallel to an axis of rotation of the respective gearwheel ( 54 , 58 ).
7. The explosion-proof limit switch ( 10 ) of claim 1 in which said gear mechanism cover plate ( 38 ), gear mechanism base plate ( 48 ) and intermediate plate ( 42 ) each are planar elements.
8. The explosion-proof limit switch ( 10 ) of claim 1 in which said gear mechanism base plate ( 48 ) and/or the gear mechanism cover plate ( 38 ) and/or the intermediate plate ( 42 ) and/or a gearwheel ( 54 , 58 ) are laser-cut.
9. The explosion-proof limit switch ( 10 ) of claim 1 in which said first gearwheel ( 54 ) and said second gearwheel ( 58 ) each have a planar upper side ( 76 ) and a planar underside ( 78 ) with all cuts through the planar sides extending transversely to the upper side ( 76 ) and underside ( 78 ).
10. The explosion-proof limit switch ( 10 ) of claim 1 in which said first gearwheel ( 54 ) meshes with said second gearwheel ( 58 ).
11. The explosion-proof limit switch ( 10 ) of claim 1 in which said gear mechanism ( 24 ) has only two gears which comprise said first gearwheel ( 54 ) and said second gearwheel ( 58 ).
12. The explosion-proof limit switch ( 10 ) of claim 1 in which said first gearwheel ( 54 ) and said second gearwheel ( 58 ) are arranged in one plane.
13. The explosion-proof limit switch ( 10 ) of claim 1 in which said shaft ( 20 ) of said actuating lever ( 18 ) is coupled with a detent arrangement ( 26 ) having a detent arrangement base plate ( 98 ), a detent arrangement cover plate ( 11 ) and at least one detent arrangement intermediate plate ( 104 , 108 ) with a pocket ( 112 ), a star wheel ( 114 ) having a star wheel plug-through opening ( 116 ) arranged in the pocket ( 112 ), and said shaft ( 20 ) of said actuating lever ( 18 ) extending through the star wheel plug-through opening ( 116 ).
14. The explosion-proof limit switch ( 10 ) of claim 1 in which said switch shaft ( 138 ) of the rotary switch ( 30 ) is a cam shaft that is engageable with a series of switch elements ( 152 ) arranged in the housing ( 12 ).