Gripper device for a bag filling and packaging machine

1. A gripper device provided in a bag filling and packaging machine in a plurality of numbers and moved along a predetermined path, changing an attitude of a bag, in a course of moving along the predetermined path, from a vertical orientation to a horizontal orientation or from a horizontal orientation to a vertical orientation, the gripper device comprising:

a movable frame which is moved along the predetermined path in a horizontal plane,

a pivot frame pivotably supported by the movable frame and having a pivot axis which is horizontal,

a pair of gripper arms provided at distal ends thereof with gripping members that hold, when closed, side edges of a bag, said gripper arms being pivotably supported by the pivot frame to open and close in conjunction with each other by being pivoted symmetrically in a plane which is parallel to the pivot axis of the pivot frame,

a bag orientation changing mechanism installed in the movable frame and linked to the pivot frame, thus pivoting the pivot frame for an angle of 90 degrees, the bag orientation changing mechanism comprising:

a first cam lever pivotably supported by the movable frame with a pivot axis thereof parallel to the pivot axis of the pivot frame,

a first cam roller rotatably installed at a free end of the first cam lever, the first cam roller configured to be displaced as the movable frame is moved along the predetermined path and the first cam roller in contact with a cam face of an orientation changing cam installed on a pedestal of the bag filling and packaging machine, and

a first linking mechanism linking the first cam lever and the pivot frame, and

a gripper arm pivot mechanism installed in the movable frame and linked to one of the gripper arms, thus pivoting the pair of gripper arms so as to adjust a reference spacing between the pair of gripper arms and open and close the pair of gripper arms.

2. The gripper device according to claim 1 , wherein

said first linking mechanism is comprised of:

a first pivot arm that pivots as the first cam roller is moved, and

a first linking rod that is linked at one end thereof to the first pivot arm and is linked at another end thereof to the pivot frame; and

the first pivot arm and the first linking rod form a toggle mechanism.

3. The gripper device according to claim 2 , wherein

said gripper arm pivot mechanism is comprised of:

a second cam lever that is pivotably supported by the movable frame with a pivot axis thereof lying in a plane which is horizontal and perpendicular to the pivot axis of the pivot frame,

a second cam roller that is rotatably installed at a free end of the second cam lever, and

a second linking mechanism that links the second cam lever and one of the gripper arms; and

the second cam roller is in contact with a cam face of a gripper pivot cam installed on a pedestal of the bag filling and packaging machine, said second cam roller being displaced as the movable frame is moved along the predetermined path.

4. The gripper device according to claim 1 , wherein

said gripper arm pivot mechanism is comprised of:

a second cam lever that is pivotably supported by the movable frame with a pivot axis thereof being horizontal and in a plane which is perpendicular to the pivot axis of the pivot frame,

a second cam roller that is rotatably installed at a free end of the second cam lever, and

a second linking mechanism that links the second cam lever and one of the gripper arms; and

the second cam roller is in contact with a cam face of a gripper pivot cam installed on a pedestal of the bag filling and packaging machine, said second cam roller being displaced as the movable frame is moved along the predetermined path.

5. A gripper device comprising:

a movable frame configured to move along a path;

a pivot frame coupled to the movable frame and configured to rotate about a first axis;

a bag orientation changing mechanism coupled to the movable frame and configured to rotate the pivot frame about the first axis, the bag orientation changing mechanism comprising:

a first cam lever coupled to the movable frame and configured to rotate about a second axis, the second axis substantially parallel to the first axis,

a first linking mechanism coupling the first cam lever to the pivot frame, and

a first cam roller coupled to the first cam lever, the first cam roller configured to:

be in contact with a face of an orientation changing cam,

be displaced as the movable frame moves along the path, and

cause the pivot frame to rotate about the first axis when the first cam roller is displaced;

at least two gripper arms coupled to the pivot frame and configured to rotate in a first plane, the first plane substantially parallel to the first axis, each gripper arm of the at least two gripper arms comprising a gripping member configured to hold a bag; and

a gripper arm pivot mechanism coupled to the movable frame and a gripper arm of the at least two gripper arms, the gripper arm pivot mechanism configured to rotate the gripper arm such that a reference spacing between the gripping members of the at least two gripper arms is adjusted.

6. The gripper device according to claim 5 , wherein:

the first linking mechanism comprises:

a first pivot arm configured to rotate as the first cam roller is displaced, and

a first linking rod coupling the first pivot arm to the pivot frame.

7. The gripper device according to claim 5 , wherein

the gripper arm pivot mechanism comprises:

a second cam lever coupled to the movable frame and configured to rotate about a third axis, the third axis in a plane substantially orthogonal to the first axis,

a second linking mechanism coupling the second cam lever to the gripper arm of the at least two gripper arms,

a second cam roller coupled to the second cam lever, the second cam roller configured to:

be in contact with a face of a gripper pivot cam,

be displaced as the movable frame moves along the path, and

cause the reference spacing between the gripping members to adjust.

8. The gripper device according to claim 6 , wherein

the gripper arm pivot mechanism comprises:

a second cam lever coupled to the movable frame and configured to rotate about third axis, the third axis in a plane substantially orthogonal to the first axis,

a second linking mechanism coupling the second cam lever to the gripper arm of the at least two gripper arms,

a second cam roller coupled to the second cam lever, the second cam roller configured to:

be in contact with a face of a gripper pivot cam,

be displaced as the movable frame moves along the path, and

cause the reference spacing between the gripping members to adjust.

9. The gripper device according to claim 5 , wherein:

the gripper arm pivot mechanism is configured to adjust the reference spacing based on a size of the bag provided.

10. The gripper device according to claim 5 , wherein:

the gripper arm pivot mechanism is configured to adjust the reference spacing when the pivot frame is in a first position and a second position, the second position different from the first position and corresponding to a position of the pivot frame after rotation about the first axis.

11. The gripper device according to claim 5 , further comprising:

at least one roller coupled to the gripping members of the at least two gripper arms and configured to be displaced; and

wherein:

the gripping member comprises:

a first clamp configured to be stationary relative to the at least two gripper arms,

a second clamp configured to move relative to the at least two gripper arms, the second clamp piece biased towards the first clamp piece, and

the at least one roller causes the gripping member to release the bag when the at least one roller is displaced.