Pick and place gripper device

1. A gripper device for picking up a pliable food product from a support surface and releasing the product, comprising:

a support;

a pair of grippers pivotally mounted on the support for movement of distal ends thereof towards and away from each other;

a belt arranged to extend directly across the gap defined between the distal ends of the grippers when they are spaced apart so that the belt is able to extend over the food product to be picked up and to extend around the food product when the grippers have been moved towards each other to pick up the food product such that distal ends of the grippers penetrate between the food product and the support surface; and

a belt tensioning arrangement that controls the tension of the belt.

2. A device of claim 1 , wherein an end portion at the distal end of each gripper is angled inwardly towards the other gripper, with respect to the radial direction from the respective gripper pivot.

3. A device of claim 1 , wherein an end portion at the distal end of each gripper defines an engagement surface which forms an obtuse angle with respect to the radial direction from the respective gripper pivot, when viewed parallel to the pivotal axis of the gripper.

4. A device of claim 3 , wherein said obtuse angle is in the range of 120° to 160°.

5. A device of claim 1 , wherein the grippers are linked together via a linkage arranged such that the grippers are rotatable in an opposite sense to each other and each rotates through substantially the same angle as the other.

6. A device of claim 1 , wherein the belt tensioning arrangement comprises a pair of arms pivotally mounted on the support, with their distal ends coupled to respective ends of the belt.

7. A device of claim 6 , wherein the arms are linked together via a linkage arranged such that the arms are rotatable in an opposite sense to each other and each rotates through substantially the same angle as the other.

8. A device of claim 6 , wherein each arm includes a pair of bars having longitudinal axes substantially parallel with the pivotal axes of the arms, and each end of the belt passes between a respective pair of bars such that friction between the belt and the bars assists in coupling the belt to the arms.

9. A device of claim 1 , wherein the belt is formed of an elastic material.

10. A device of claim 1 , wherein each end of the belt is attached to a respective gripper.

11. A method for picking up a pliable food product from a support surface with a gripper device as claimed in claim 1 , comprising:

pivoting the pair of grippers towards each other such that their distal ends penetrate between the food product and the support surface, with the belt sandwiched between each gripper and the food product and extending between the grippers above the food product, until the gripper device is able to lift the food product from the support surface and

controlling the tension of the belt with the belt tensioning arrangement.

12. A method of claim 11 , including a step of increasing the tension in the belt with the belt tensioning arrangement, thereby drawing the belt out from between the grippers so that it wraps more tightly around the food product to retain it in position.

13. A method of claim 11 including a step of releasing the food product by driving the grippers apart.

14. A method of any of claim 11 , including a step of increasing tension in the belt with the belt tensioning arrangement, thereby driving the grippers apart and releasing the food product.

15. A method of claim 11 including a step of releasing the food product by reducing or removing force applied to the grippers, allowing tension in the belt to force the grippers apart.

16. A method of claim 11 for picking up a pliable food product wherein the food product is reshaped into a more compact configuration by the grippers and belt as it is picked up.