Bag filling and packaging method and bag filling and packaging apparatus

Abstract

A bag filling and packaging system including gripper pairs around a rotating table so that the grippers of each gripper pair grip two side edges of a bag on which various packaging processes are performed. A gripper distance adjustment auxiliary cam is provided to ascend and descend relative to a gripper distance setting cam for setting distance between grippers. A roller rolls on the two cams as the table rotates, and the distance between the grippers changes in response to the height of the roller by a transmission mechanism. An apparent bag width is measured prior to gripping a bag, the height of the gripper distance adjustment auxiliary cam is controlled according to this measured value, and the distance between grippers in a bag supply process is adjusted accordingly, the amount of part gripped by the grippers at side edges of a bag thus being constant for all bags.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of a bag filling and packaging apparatus according to the present invention;

FIG. 2 shows in cross section the gripper distance setting cam and a gripper distance adjustment auxiliary cam, as well as a drive means for the gripper distance adjustment auxiliary cam in the bag filling and packaging apparatus of the present invention;

FIG. 3 is a side elevation thereof;

FIG. 4 shows in cross section the gripper distance adjusting mechanism in the bag filling and packaging apparatus of the present invention;

FIG. 5 is an expanded diagram of the gripper distance setting cam and gripper distance adjustment auxiliary cam according to the first embodiment of the present invention, FIG. 5 showing also the positions of various processes;

FIG. 6 is an expanded diagram of the gripper distance setting cam and gripper distance adjustment auxiliary cam according to the first embodiment of the present invention, FIG. 6 showing also the positions of various processes;

FIG. 7 is a top view showing the distance between grippers (in a bag supply process) according to the first embodiment of the present invention;

FIG. 8 is an expanded diagram of the gripper distance setting cam and gripper distance adjustment auxiliary cam according to the second embodiment of the present invention, FIG. 8 showing also the positions of various processes;

FIG. 9 is an expanded diagram of the gripper distance setting cam and gripper distance adjustment auxiliary cam according to the second embodiment of the present invention, FIG. 9 showing also the positions of various processes;

FIG. 10 is a top view showing the distance between grippers (in a steam blowing process) according to the second embodiment of the present invention;

FIG. 11 illustrates, using a top view of a gripper pair, problems, in a conventional bag filling and packaging apparatus, when the apparent bag width of a bag differs from a nominal value;

FIG. 12 illustrates, using a top view of a gripper pair, problems, in a conventional bag filling and packaging apparatus, when the apparent bag width of a bag differs from a nominal value;

FIG. 13 is an expanded diagram of a gripper distance setting cam and gripper distance adjustment auxiliary cam of a conventional bag filling and packaging apparatus, FIG. 13 showing also the positions of various processes.

Claims

1. A bag filling and packaging method, wherein: with a plurality of gripper pairs, each for gripping left and right side edges of a bag, being provided at equal distance about a carrying member that rotates along a circular path,bags are supplied to each gripper pair so that, while said carrying member makes one revolution, a bag gripped by said gripper pair is subjected sequentially to packaging processes including bag mouth opening, contents charging, and bag mouth sealing;said method comprising the steps of: measuring an apparent bag width of each one of the bags prior to gripping the bag with said gripper pair; andadjusting, according to an obtained measured value, a distance between grippers of said gripper pair when said gripper pair grips two side edges of a bag, so that an amount of part gripped by said gripper pair at side edges of a bag is constant for all of bags.

2. A bag filling and packaging method, wherein: with a plurality of gripper pairs, each for gripping left and right side edges of a bag, being provided at equal distance about a carrying member that rotates along a circular path,bags are supplied to each gripper pair so that, while said carrying member makes one revolution, a bag gripped by said gripper pair is subjected sequentially to packaging processes including bag mouth opening, contents charging, and bag mouth sealing;in said bag filling and packaging method: a reference value, based on a nominal bag width value, being set for a distance between grippers of said gripper pair corresponding to each one of said packaging processes, anda distance between grippers of said gripper pair, when said gripper pair grips two side edges of a bag in a bag supplying process, being adjustable to a size equal to or below said reference value; andsaid method comprising the steps of: measuring an apparent bag width of each one of the bags prior to gripping the bag with said gripper pair; andadjusting, according to an obtained measured value, a distance between grippers of said gripper pair when said gripper pair grips two side edges of a bag, so that an amount of part gripped by said gripper pair at side edges of a bag is constant for all of bags.

3. A bag filling and packaging apparatus, wherein: a plurality of gripper pairs, each for gripping left and right side edges of a bag, are provided at equal distance about a carrying member that rotates along a circular path, andbags are supplied to each gripper pair so that, while said carrying member makes one revolution, a bag gripped by said gripper pair is subjected sequentially to packaging processes including bag mouth opening, contents charging, and bag mouth sealing;in said bag filling and packaging apparatus: a reference value, based on a nominal bag width value, being set for a distance between grippers of said gripper pair corresponding to each one of said packaging processes, anda distance between grippers of said gripper pair, when said gripper pair grips two side edges of a bag in a bag supplying process, being adjustable to a size equal to or below said reference value; andsaid bag filling and packaging apparatus comprising: a bag width measurement means for measuring an apparent bag width of each one of the bags prior to gripping the bag with said gripper pair,a gripper distance adjustment means for adjusting a distance of grippers of said gripper pair when said gripper pair grips two side edges of a bag; anda control means for controlling said gripper distance adjustment means according to bag width measurement values and adjusting a distance between grippers to a value equal to or below the reference value, so that an amount of part gripped by said gripper pair at side edges of a bag is constant for all of bags.

4. The bag filling and packaging apparatus according to claim 3, wherein: said carrying member is a revolving table;a gripper distance setting cam for setting the distance between said grippers to a reference value is provided to surround a circumference of a table rotating shaft, an upper surface of said gripper distance setting cam making a cam surface;said gripper distance adjustment means is comprised of a gripper distance adjustment auxiliary cam having a cam surface on an upper surface thereof, said gripper distance adjustment auxiliary cam being provided at predetermined positions in a circumferential direction of said gripper distance setting cam so as to be ascendable and descendable relative to said gripper distance setting cam, anda drive mechanism for causing said gripper distance adjustment auxiliary cam to ascend and descend;an urging means is provided in each one of said gripper pairs for urging grippers thereof so as to narrow a distance between said grippers; anda transmission mechanism is provided in said table for each one of said gripper pairs, said transmission mechanism comprising a roller that rolls along cam surfaces of said two cams for, against an urging force of said urging means, transmitting displacement of said roller to said gripper pair, thus opening said grippers of said gripper pair to a distance that corresponds to heights of said cam surfaces.

5. A bag filling and packaging method, wherein: with a plurality of gripper pairs, each for gripping left and right side edges of a bag, being provided at equal distance about a carrying member that rotates along a circular path,bags are supplied to each gripper pair so that, while said carrying member makes one revolution, a bag gripped by said gripper pair is subjected sequentially to packaging processes including bag mouth opening, contents charging, and bag mouth sealing;said method comprising the steps of: measuring an apparent bag width of each one of the bags andadjusting said distance between said grippers, according to a measured value of the apparent bag width, when, in one or more processes after a bag supplying process, said distance between said grippers is widened greater than a distance between grippers in said bag supplying process so that a degree of bag tension in said one or more processes after said bag supplying process is constant for all of bags.

6. A bag filling and packaging method, wherein: with a plurality of gripper pairs, each for gripping left and right side edges of a bag, being provided at equal distance about a carrying member that rotates along a circular path,bags are supplied to each gripper pair so that, while said carrying member makes one revolution, a bag gripped by said gripper pair is subjected sequentially to packaging processes including bag mouth opening, contents charging, and bag mouth sealing;in said bag filling and packaging method: a reference value, based on a nominal bag width value, being set for a distance between grippers corresponding to each one of said packaging processes; anda distance between grippers of said gripper pair in one or more processes, for which a reference value greater than a reference value in a bag supplying process is set, being able to be set to be a size equal to or greater than a reference value in said one or more processes; andsaid method comprising the steps of: measuring an apparent bag width of each one of the bags andadjusting a distance between grippers of said gripper pair, according to a measured value of the apparent bag width in said one or more processes after said bag supplying process, to a size equal to or greater than a reference value in said one or more processes, so that a degree of bag tension in said one or more processes after said bag supplying process is constant for all of bags.

7. A bag filling and packaging apparatus, wherein: a plurality of gripper pairs, each for gripping left and right side edges of a bag, are provided at equal distance about a carrying member that rotates along a circular path, andbags are supplied to each gripper pair so that, while said carrying member makes one revolution, a bag gripped by said gripper pair is subjected sequentially to packaging processes including bag mouth opening, contents charging, and bag mouth sealing;in said bag filling and packaging apparatus: a reference value, based on a nominal bag width value, being set for a distance between grippers corresponding to each one of said packaging processes, anda distance between grippers of said gripper pair in one or more processes, for which a reference value greater than a reference value in a bag supplying process is set, being able to be set to be a size equal to or greater than a reference value in said one or more processes; andsaid bag filling and packaging apparatus comprising: a bag width measurement means for measuring an apparent bag width of each one of the bags;a gripper distance adjustment means for adjusting said distance between said grippers in said one or more processes after said bag supplying process; anda control means for controlling said gripper distance adjustment means according to a bag width measurement value and for adjusting said distance between grippers in said one or more processes after said bag supplying process to a value that is greater than said reference value by a difference between said nominal value and said measured value.

8. The bag filling and packaging apparatus according to claim 7, wherein: said carrying member is a revolving table;a gripper distance setting cam for setting the distance between said grippers to a reference value is provided to surround a circumference of a table rotating shaft, an upper surface of said gripper distance setting cam being a cam surface; said gripper distance adjustment means is comprised of a gripper distance adjustment auxiliary cam having a cam surface on an upper surface thereof, said gripper distance adjustment auxiliary cam being provided at predetermined positions in a circumferential direction of said gripper distance setting cam so as to be ascendable and descendable relative to said gripper distance setting cam, anda drive mechanism for causing said gripper distance adjustment auxiliary cam to ascend and descend;an urging means is provided in each one of said gripper pairs for urging grippers thereof so as to narrow a distance between said grippers; anda transmission mechanism is provided in said table for each one of said gripper pairs, said transmission mechanism comprising a roller that rolls along cam surfaces of said two cams for, against an urging force of said urging means, transmitting displacement of said roller to said gripper pair, thus opening said grippers of said gripper pair to a distance that corresponds to heights of said cam surfaces.