Ultrasonic welding device and method of operating said device

1. An ultrasonic welding device comprising:

an adapter frame, an ultrasonic horn and a converter, said ultrasonic horn being driven by the adapter frame mounted converter for ultrasonic welding of workpieces to at least one fixed workpiece on a tooling, said workpieces being particularly preforms,

wherein said at least one fixed workpiece is a fiber reinforced plastics (FRP) component, wherein said ultrasonic horn is movable towards the workpieces, the ultrasonic horn being centrally inside the adapter frame, and wherein the ultrasonic welding device further comprises a pick member;

wherein the pick member comprises:

a press pad mounted resiliently to said adapter frame,

passive clamping means located on the press pad for improved adherence of the workpieces when the press pad exerts a pressure on the workpieces, and

grippers located on the press pad and suitable for the workpieces so that the workpieces are movable to a weld position at the fixed workpiece by means of control means controlling the coordinates of the ultrasonic welding device relative to the workpieces and activation means for controlled activation of the pick member and the ultrasonic horn.

2. The ultrasonic welding device according to claim 1 , wherein the control means and the activation means are configured to perform conveyance and a subsequent ultrasonic welding operation with said workpieces and fixed workpiece on the tooling.

3. The ultrasonic welding device according to claim 1 , wherein the grippers are pneumatic-, needle- or freezing-grippers.

4. The ultrasonic welding device according to claim 2 , wherein the activation means comprise pneumatic supply means.

5. The ultrasonic welding device according to claim 4 , wherein the pneumatic supply means are fed by pressure or vacuum supply means.

6. The ultrasonic welding device according to claim 1 , wherein the press pad comprises a preferably central cut out for said ultrasonic horn.

7. The ultrasonic welding device according to claim 1 , wherein the press pad is with regard to said ultrasonic horn symmetrically mounted by spring legs to the adapter frame.

8. The ultrasonic welding device according to claim 1 , wherein the passive clamping means of the press pad comprises a clamping ring or clamping surface.

9. The ultrasonic welding device according to claim 1 , wherein the press pad has an essentially circular or rectangular shaped surface for contact to the workpieces and/or to the at least one fixed workpiece on the tooling.

10. The ultrasonic welding device according to claim 1 , wherein the adapter frame is adjustable coaxial to said ultrasonic horn.

11. The ultrasonic welding device according to claim 1 , wherein the device is operated manually.

12. A method of operating the ultrasonic welding device according to claim 1 , characterized by first moving said ultrasonic welding device by means of a mechanism towards workpieces, such as workpieces to be welded, activating grippers of a pick member at an ultrasonic horn by means of a control unit and gripping the workpieces by means of the grippers, moving the workpieces to a weld position with a fixed workpiece at a tooling by means of the mechanism of the ultrasonic welding device, applying pressure to the workpieces and the fixed workpiece at the tooling to be welded by means of the passive clamping means of the press pad once the weld position is reached, moving the ultrasonic horn to compress the workpieces to the fixed workpiece at the tooling, inducing ultrasound through the ultrasonic horn to the workpieces to be welded to the fixed workpiece on the tooling and accomplishing the weld.

13. The method according to claim 12 , characterized by adjusting the distance of the press pad relative to the ultrasonic horn.

14. The method according to claim 12 , characterized by clamping the workpieces to be welded to the fixed workpiece at the tooling by means of the ultrasonic horn.

15. An ultrasonic welding device comprising:

an adapter frame;

a converter mounted to the frame;

an ultrasonic horn mounted in a central region of the frame and driven by the converter, the horn adapted for ultrasonic welding a preform workpiece to a fixed workpiece made of a fiber reinforced plastic on a tooling;

a pick member mounted to an end of the frame by a series of spring legs, the pick member having a press pad defining a central cut out surrounded by a clamping surface and a series of grippers; and

at least one controller configured to control coordinates of the adapter frame and control the pick member to move the preform workpiece to a weld position at the fixed workpiece, and control the converter and the ultrasonic horn;

wherein the ultrasonic horn passes through the cut out of the press pad when the spring legs are in a compressed state to contact the preform workpiece.

16. The ultrasonic welding device of claim 15 wherein the ultrasonic horn is perpendicular to the clamping surface of the press pad.

17. The ultrasonic welding device of claim 15 wherein the grippers are pneumatic grippers; and

wherein each gripper of the series of grippers is positioned at an end of a respective spring leg of the series of spring legs, a pneumatic supply line integrated into the spring leg and in fluid communication with the gripper.

18. The ultrasonic welding device of claim 15 wherein the clamping surface comprises a tacky cork.

19. The ultrasonic welding device of claim 15 wherein the clamping surface of the press pad is configured to exert a passive clamping force on the preform workpiece and the fixed workpiece as a function of a stiffness and a spring stroke of each spring leg of the series of spring legs.

20. The ultrasonic welding device of claim 15 wherein the adapter frame has longitudinal slits; and

wherein the converter and the ultrasonic horn are connected to the adapter frame using screws extending through the longitudinal slits of the adapter frame; and

wherein a distance of the ultrasonic horn relative to the press pad is configured to be adjusted by changing a position of the screws within the longitudinal slits.