Device for compensating joining motions

1. Joining unit ( 10 , 40 ) for an articulated arm robot ( 12 , 44 ) for joining a component ( 24 , 58 ) with a joining element ( 28 , 60 ) by applying an axial force, with the joining unit ( 10 , 40 ) comprising:

a base element ( 14 , 42 ) for connecting to an articulated arm robot ( 12 , 44 ),

an advancing unit ( 13 , 46 ) connected to and movable relative to the base element ( 14 , 42 ) in an axial direction in and against a setting direction,

a setting device ( 16 , 54 ) connected to and movable together with the advancing unit ( 13 , 46 ), wherein the setting device comprises a rotary spindle ( 16 , 54 ),

a coupling unit connected to the advancing unit,

a pressure piece ( 26 , 50 ) mounted for movement relative to the advancing unit ( 13 , 46 ) in and against the setting direction and being furthermore connected to the advancing unit ( 13 , 46 ) by means of the coupling unit ( 17 , 48 ),

wherein the coupling unit ( 17 , 48 ) comprises a blocking unit ( 18 , 56 ) which, starting from a predefined axial blocking position, prevents movement of the pressure piece ( 26 , 50 ) relative to the advancing unit ( 13 , 46 ) against the setting direction so long as an advancing force of the advancing unit is less than a set blocking force, which blocking unit comprises a release device ( 20 , 62 ) by means of which the relative movement of the pressure piece ( 26 , 50 ) against the setting direction is enabled, wherein the blocking unit ( 18 , 56 ) comprises a pneumatic cylinder or a hydraulic cylinder.

2. Joining unit according to claim 1 , wherein the blocking unit ( 18 , 56 ) is designed such that the blocking force is constant.

3. Joining unit according to claim 1 , wherein the blocking unit ( 18 , 56 ) comprises one of: a valve, a control valve or a pressure relief valve, which is connected to the cylinder.

4. Joining unit according to claim 1 , wherein the release device comprises a bleed valve ( 20 , 62 ).

5. Joining unit according to claim 1 , wherein the blocking unit ( 18 , 56 ) comprises an electric motor.

6. Joining unit according to claim 1 , wherein the blocking unit ( 18 , 56 ) acts directly on the pressure piece ( 26 , 50 ).

7. Joining unit according to claim 1 , wherein the blocking unit ( 18 , 56 ) comprises a contact element which acts on the component ( 24 , 58 ) to be joined.

8. Joining unit according to claim 1 , wherein the coupling unit ( 48 ) comprises a spring ( 52 ) which sets a base position of the pressure piece ( 50 ) relative to the advancing unit ( 46 ).

9. Joining unit according to claim 1 , wherein after actuation of the release device ( 20 , 62 ), the advancing force acts on the joining element via the setting device ( 16 , 54 ).

10. Joining unit according to claim 1 , wherein a placement contact detection means ( 25 ) is connected to the advancing unit ( 13 ) which detects the point in time when the joining element makes placement contact with the component ( 28 ), whereupon the release device ( 20 ) is actuated.

11. Joining unit according to claim 10 , wherein the placement contact detection means ( 25 ) comprises a force sensor which is connected to the setting device ( 16 , 54 ) and detects the axial process force acting on the setting device ( 16 , 54 ).

12. Joining unit according to claim 10 , wherein the placement contact detection means ( 25 ) operates via motion of the advancing unit ( 13 ).

13. Joining unit according to claim 1 , wherein the rotary spindle is capable of producing a speed of between 3,000 and 10,000 revolutions per minute to produce one or a combination of: a force-locking, a positive-locking or a material-locking connection.

14. Joining unit according to claim 1 , wherein the setting device is guided through the pressure piece ( 26 , 50 ), the pressure piece ( 26 , 50 ) being of a hollow-cylindrical design.

15. Joining unit according to claim 1 , wherein the advancing force is maintained constant during the pretensioning operation and after actuation of the release device ( 20 , 62 ).

16. An apparatus for joining a component ( 24 , 58 ) with a joining element ( 28 , 60 ) using an articulated robot, comprising:

an advancing unit ( 13 , 46 ) being provided on the articulated robot and being axially movable,

a joining element ( 28 , 60 ) coupled to the advancing unit and brought into contact with the component ( 24 , 58 ) by axial movement of the advancing unit,

a setting device ( 16 , 54 ) which can be fitted with the joining element ( 28 , 60 ) and is movable toward the component ( 24 , 58 ), wherein the setting device comprises a rotary spindle ( 16 , 54 ),

a blocking device limiting the movement of the setting device ( 16 , 54 ) relative to the component ( 24 , 58 ) by means of a pressure piece ( 26 , 50 ), so long as an advancing force applied to the setting device is less than a preset blocking force, wherein the blocking device is released once the joining element ( 28 , 60 ) makes contact with the component, causing the advancing force equivalent to the blocking force to be transmitted via the setting device ( 16 , 54 ) and the joining element ( 28 , 60 ) and thus to the component ( 24 , 58 ), wherein the blocking device comprises a pneumatic cylinder ( 18 , 56 ) or a hydraulic cylinder.

17. Apparatus according to claim 16 , wherein the advancing force equivalent to the blocking force continues to act until the joining operation has been completed.

18. Apparatus according to claim 16 , wherein the advancing force is kept constant over the entire joining process.