Control device

1. A control device ( 10 , 10 ′, 10 ″; 24 , 24 ′) comprising:

a control unit ( 10 , 10 ′, 10 ″) with a control element ( 12 ) for controlling a fluid flow and being rotatable about a first axis ( 13 ) between an open position and a closed position,

a separate, attachable motor-driven actuator unit ( 24 , 24 ′), which is mechanically coupled to said control unit ( 10 , 10 ′, 10 ″) to rotate said control element ( 12 ) about said first axis ( 13 ) in a controllable fashion,

whereby said actuator unit ( 24 , 24 ′) comprises a driving part ( 25 ) with a driving element ( 31 ) being rotatable about a second axis ( 26 ), to be mechanically coupled to said control element ( 12 ) in a coupling position to rotate said control element ( 12 ) about said first axis ( 13 ), and a control part ( 28 ) for driving said driving element ( 31 ) in a controllable fashion,

wherein said driving element ( 31 ) is coupled to said control unit ( 10 , 10 ′, 10 ″) by means of a spur gearing (Hirth serration) ( 22 , 29 ),

wherein said control element ( 12 ) is provided with a first spur gearing ( 22 ), that said driving element ( 31 ) is provided with a second spur gearing ( 29 ) being complementary to said first spur gearing ( 22 ), and that in said coupling position of said control unit ( 10 , 10 ′, 10 ″) and said actuator unit ( 24 , 24 ′) said first and second axes ( 13 , 26 ) are in coaxial alignment, whereby said first and second spur gearings ( 22 , 29 ) are engaged with each other in a non-rotatable fashion, and

wherein said first and second spur gearings ( 22 , 29 ) are held in said coupling position by holding means ( 20 ; 34 , 35 ) provided on said control unit ( 10 , 10 ′, 10 ″).

2. The control device as claimed in claim 1 , wherein said holding means ( 20 ; 34 , 35 ) comprises a spring ( 20 ), which axially presses said first and second spur gearings ( 22 , 29 ) against each other.

3. The control device as claimed in claim 2 , wherein said spring ( 20 ) is configured to receive said driving part ( 25 ) of said actuator unit ( 24 ) and to be tensioned by said driving part ( 25 ), when said actuator unit ( 24 ) is brought into said coupling position in a movement perpendicular to said first and second axes ( 13 , 26 ).

4. The control device as claimed in claim 1 , wherein said holding means ( 20 ; 34 , 35 ) comprises lateral latching guides ( 34 , 35 ), which catch and hold said actuator unit ( 24 ′), such that said first and second spur gearings ( 22 , 29 ) are held in said coupling position.

5. The control device as claimed in claim 1 , wherein that an actuator receptacle ( 15 , 15 ′) is provided on said control unit ( 10 , 10 ′), which receives and guides said actuator unit ( 24 , 24 ′), when it is brought into said coupling position in said movement perpendicular to said first and second axes ( 13 , 26 ).

6. The control device as claimed in claim 5 , wherein said actuator receptacle ( 15 ) comprises a rectangular box ( 16 ) with two parallel side walls ( 16 a,b ), a rear wall ( 16 d ) and a bottom ( 16 c ), which box ( 16 ) is open at its front side to receive said actuator unit ( 24 ) in a sliding fashion, when it is brought into said coupling position.

7. The control device as claimed in claim 6 , wherein said actuator unit ( 24 ) has two parallel side cheeks ( 28 a,b ) which abut against said side walls ( 16 a,b ) of said box ( 16 ), when said actuator unit ( 24 ) laterally slides into said box ( 16 ) in order to be brought into said coupling position.

8. The control device as claimed in claim 7 , wherein said box ( 16 ) is open at the top, and that a spring ( 20 ) extends into said open top essentially parallel to said bottom ( 16 c ) with a resilient latching section ( 20 b ).

9. The control device as claimed in claim 8 , wherein said resilient latching section ( 20 b ) of said spring ( 20 ) is provided with an opening ( 21 ), which receives in a latching action a latching element ( 27 ) provided on said driving part ( 25 ) of said actuator unit ( 24 ), when said actuator unit ( 24 ) laterally slides into said box ( 16 ) in order to be brought into said coupling position.

10. The control device as claimed in claim 5 , wherein said actuator receptacle ( 15 ′) comprises a bottom plate ( 32 ), which receives said actuator unit ( 24 ′) in a sliding fashion, when it is brought into said coupling position, a rear wall ( 33 ) acting as a stop for said actuator unit ( 24 ′), and opposite lateral latching guides ( 34 , 35 ), which guide said actuator unit ( 24 ′) laterally and keep it in said coupling position.

11. The control device as claimed in claim 5 , wherein said first spur gearing ( 22 ) of said control element ( 12 ) extends into said actuator receptacle ( 15 , 15 ′)) through an opening in a bottom ( 16 c ; 32 ) of said actuator receptacle ( 15 , 15 ′).

12. The control device as claimed in claim 8 , wherein a sliding ridge ( 19 ) is provided on the bottom ( 16 c ) of said box ( 16 ) for lifting said actuator unit ( 24 ) against the resilient latching section ( 20 b ) of said spring ( 20 ), when said actuator unit ( 24 ) slides into said box ( 16 ) in order to be brought into said coupling position.

13. The control device as claimed in claim 10 , wherein a sliding ridge ( 19 ′) is provided on said bottom plate ( 32 ) of said actuator receptacle ( 15 ′), that said actuator unit ( 24 ′) is provided with guiding rails ( 36 ), which engage with respective recesses ( 37 ) in said sliding ridge ( 19 ′) in order to prevent rotational motion of said actuator unit ( 24 ′) about said second axis.

14. The control device as claimed in claim 1 , wherein said control unit ( 10 , 10 ′) is an air damper or valve of an HVAC system.