GB2065060A

GB2065060A - Method and apparatus for opening and applying bags to a filling nozzle

Info

Publication number: GB2065060A
Application number: GB8039747A
Authority: GB
Original assignee: Haver and Boecker OHG
Current assignee: Haver and Boecker OHG
Priority date: 1979-12-17
Filing date: 1980-12-11
Publication date: 1981-06-24
Also published as: ATA558280A; DE2950822A1; DE2950822C2; AT386580B; FR2471918A2; GB2065060B; FR2471918B2

Abstract

In apparatus for transferring bags to a filling nozzle 1, in which bags 6 with side folds are individually gripped by grippers 7 which grip the side edges of the bag below the mouth and swing from a support 5 to an opening station where the bag 6 is taken over by suction bars 20, 21, the outer gripping ends 14 of the grippers 7 are pivotable laterally apart about axes 15 by cylinders 17, on swinging back of the grippers so that they clear the bag taken over by the suction bars 20, 21. The suction bars move apart to open the bag thereby along the entry of spreader fingers (40) which transfer the opened bag from the suction bars to the filling nozzle (1). <IMAGE>

Description

SPECIFICATION Method and apparatus for opening and applying prefabricated bags, preferably bags with side folds The invention relates to a method and apparatus for opening and applying prefabricated bags, particularly bags with side folds made of plastics or multi-ply paper to the filling nozzle of a filling machine.

Good bagging performance in filling bags with side folds is only obtainable if the bag is applied to the filling nozzle when fully open in cross-section, and if the dispensing cross-section of the nozzle is large enough.

According to the invention there is provided a method of opening and applying prefabricated bags, particularly bags with side folds made of plastics or multi-ply paper, to the filling nozzle of a filling machine, wherein the bags are individually and successively engaged by a pair of grippers in a gripping station, the grippers taking hold of a bag at the sides below its upper end, at which upper end the mouth of the bag is located, and transporting it to an opening station, where the bag is engaged and opened by suction bars, receives a pair of spreader fingers, and is transported to and applied to the filling nozzle by the pair of spreader fingers, wherein, in the opening station and afterthe bag has been taken over by the suction bars, the gripping ends of the grippers, provided with clamping jaws, are swung outwards relative to the bag and the grippers are moved back along a path from the opening station to the gripping station with the gripping ends still swung out, at least until they are clear of the bag located at the opening station.

In the case of bags with side folds, the bag can be received by the opening station in a very reliable way, so that complete opening can be obtained, and so that the bags can be applied to the filling nozzle with optimum opening of their filling cross-section.

The fact that the gripping ends are swung outwards when the suction bars have received the bag in the opening station firstly provides adequate space to enable the maximum opening cross-section of the bag to be obtained, with the side folds being utilised. Since the grippers are swung back into the gripping station with their gripping ends swung out, the grippers cannot come into collision on the way there with the bag hanging freely in the opening station, and the bag cannot be stripped off the suction bars.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is an elevation showing a filling nozzle of a filling machine and apparatus according to the invention for opening and applying a bag with side folds; Figure 2 is a plan view of grippers of the apparatus of Figure 1 which transport the bag to the opening station, and of suction bars of the opening station and their drive means; and Figure 3 is a plan view of the apparatus of Figures 1 and 2 in the region of the opening station, showing spreader fingers, which take on the bag in the opening station and transport it to the filling nozzle.

Referring to the drawings, a filling machine 1 has a filling nozzle 2 which is provided with spreader flaps 3 and clamping jaws 4. The edge of the mouth of a bag, which is placed over the closed spreader flaps 3, can be anchored to the flaps by the clamping jaws 4.

In a gripping station 5, a bag 6 with side folds is engaged by two grippers 7, which are mounted so as to pivot about a horizontal axis 8. The grippers take hold of the bag by their clamping jaws 9, 10 in a position below the upper end of the bag, at which upper end the mouth of the bag is located, the clamping jaws 9, 10 gripping the bag in the region of the side folds thereof. Each clamping jaw 10 is disposed at the front end of the piston rod of a respective tightening cylinder 11. The jaw 9 is formed by one limb of a U-piece 12, while the tightening cylinder is attached to the other limb 13 of the U-piece.

The U-piece 12 and cylinder 11 together form a gripping end 14. This can be swung out about an axis 15 relative to the rest of the gripping member 16, from a position of alignment with the gripping member 16.

The swung-out position of the gripping ends is shown in dash-and-dot lines in Figure 2. Each gripping end 14 is pivoted about its respective vertical axis 15 by means of a piston-cylinder unit 17, the piston rod 18 of which is articulated to a laterally projecting arm 19 ofthe gripping end 14. The arm 19 is provided in the region of the joint connection between the gripping end 14 and the gripping member 16. By means of the grippers 7, a bag with side folds is transported from the gripping station to the opening station in the course of a pivoting movement about the axis 8. In the opening station the edge of the mouth of the bag located above the grippers assumes a position midway between suction bars 20 and 21, which receive the bag from the grippers 7.

After engaging the bag, the suction bars 20,21 are moved simultaneously in opposite directions from the centre plane 22 of the opening station, with the same stroke.

When the bag has been taken over by the suction bars 20, 21 and before the bars carry out their opening movement, the gripping ends 14 are swung out about the pivot axes 15 by means of the pistoncylinder units 17. The swung-out position of the gripping ends, illustrated in dash-and-dot lines in Figure 2, shows that the side folds of the bag can be pulled right out by the opening movement of the suction bars, to give a maximum opening crosssection for the mouth of the bag. There is no danger that parts of the bag will come into contact with the gripping ends 14. The grippers 7 are then moved back to the gripping station with their gripping ends 14 swung out. In this way there is again no danger of the grippers colliding with the bag hanging freely in the opening station.

In the gripping station the gripping ends 14 are moved back into alignment with the other part of the grippers, before a new bag is gripped by the clamping jaws of the grippers.

The suction bars 20, 21 are moved in opposite directions by means of a drive and a coupling mechanism. The drive is a piston-cylinder unit 23 which is arranged below a support 24. Guide means for the suction bars 20 and 21 are provided on the support 24.

The couping mechanism interpolated between the suction bars 20, 21 and the piston-cylinder unit 23 has a cross head 26 rotatable about a vertical axis 25.

The ends of the head 26 are connected to guide members 27,28, which are joined pivotably to the suction bars 20,21 or to parts fixed to the bars. The transverse head 26 is joined to a strap 29, which is engaged by the piston rod of the piston-cylinder unit 23.

The suction bar 20 nearertothe nozzle 2 has a U-shaped bridge member 30 fixed to it. The member 30 engages around the other suction bar 21 and is connected to the coupling mechanism and the guide member 28 by a vertical web 31.

Guide rods 32 for the suction bar 20 are fixed to the vertical web 31. The rods 32 are mounted so as to slide within sleeves 33 fixed to the support 24. The guide member 27 leads to a component connected to the suction bar 21. When the piston-cylinder unit 23 is actuated, a movement in opposite directions is imparted to the suction bars 20, 21 by means of the coupling mechanism described. The guide means associated with the suction bar 21 and disposed on the support 24 comprises guide rods 34, which are mounted so as to slide within sleeves 35. The sleeves 35 are fixed to the support 24. The rear ends of the guide rods are connected by a transverse web 36. This is provided with a central threaded hole to receive an abutment screw 37. The screw cooperates with a stationary stop 38 at the end of the stroke of the suction bar. The stroke can thus be varied by means of the adjustable abutment screw 37.

With the aid of a rod mechanism 39 the vertical position of the support 24 and thus of the suction bars 20,21 can be adjusted by pivoting about the axis 8.

When the bag 6 has been opened by the suction bars 20,21, spreader plates 40 on fingers 41 are moved into the mouth of the bag and swung out about respective axes 42 by means of pistoncylinder units 43. When the bag has been taken over by the spreader fingers the suction bars 20,21 are moved upwards by the rod mechanism 39 and assume the positions shown in dash-and-dot lines in Figure 1.

The spreader fingers are connected to swinging supports 44,45 and are moved towards the nozzle 2 by means of a piston-cylinder unit 46. A pistoncylinder unit 48 is provided for further adjusting movement of the fingers about a horizontal axis 47.

Claims

1. A method of opening and applying prefabricated bags, particularly bags with side folds made of plastics or multi-ply paper, to the filling nozzle of a filling machine, wherein the bags are individually and successively engaged by a pair of grippers in a gripping station, the grippers taking hold of a bag at the sides below its upper end, at which upper end the mouth of the bag is located, and transporting it to an opening station, where the bag is engaged and opened by suction bars, receives a pair of spreader fingers, and is transported to and applied to the filling nozzle by the pair of spreader fingers, wherein, in the opening station and afterthe bag has been taken over by the suction bars, the gripping ends of the grippers, provided with clamping jaws, are swung outwards relative to the bag and the grippers are moved along a path from the opening station to the gripping station with the gripping ends still swung out, at least until they are clear of the bag located at the opening station.

2. A method according to claim 1, in which in the gripping station the gripping ends are swung back into a position of alignment with remaining parts of the grippers.

3. A method according to claim 1 or claim 2, in which the bag is transported into a centre plane of the opening station by the grippers, and to open the bag the suction bars are moved away from said centre plane simultaneously in opposite directions with an identical stroke.

4. Apparatus for opening and applying prefabricated bags, particularly bags with side folds made of plastics or multi-ply paper, to the filling nozzle of a filling machine, comprising a pairofgrippers indi viduallyand successively to engage the bags in a gripping station, the grippers taking hold of a bag at the sides below its upper end, at which upper end the mouth of the bag is located, and transporting it to an opening station, suction bars at the opening station to engage and open the bags, a pair of spreader fingers at the opening station to transport to and apply the bags to the filling nozzle by the pair of spreader fingers, wherein the grippers each have a respective gripping end provided with clamping jaws which can be swung outwards relative to the bag in the opening station and afterthe bag has been taken over by the suction bars, so that the grippers can be moved back along a path from the opening station to the gripping station with the gripping ends still swung out, at least until they are clear of the bag located at the opening station.

5. Apparatus according to claim 4, in which the gripping ends equipped with clamping jaws, each have a tightening cylinder with a piston rod, the free end of which cylinder forms the movable clamping jaw, and the gripping ends can be swung out about an axis perpendicular to a remaining part ofthe gripper, by means of a piston-cylinder unit connected to the gripper.

6. Apparatus according to claim 4, in which each gripping end is provided with a laterally projecting arm in the region of its joint connection to the remaining part of the gripper, the piston rod of the piston-cylinder unit being connected to said arm.

7. Apparatus according to any one of claims 4 to 6, in which the suction bars can be moved in opposite directions by means of a drive and a coupling mechanism.

8. Apparatus according to claim 7, in which the drive is in the form of a piston-cylinder unit disposed below a support for guide means of the suction bars.

9. Apparatus according to claim 7 or claim 8, in which the coupling mechanism comprises a cross head rotatable about a vertical axis, the ends of the head being connected to guide members which are joined flexibly to the suction bars or to components fixed to the suction bars, and a strut which is engaged by the piston rod ofthe piston-cylinder unit is connected to the cross head.

10. Apparatus according to claim 8, in which the guide means comprise a guide rod and a sleeve fixed to the support, and the stroke of the suction bars can be limited by an adjustable stop.

11. Apparatus according to claim lOin which the ends of two guide rods associated with one of the suction bars are joined by a transverse web, and the transverse web contains a threaded hole with an abutment screw, which co-operates with a stationary stop at the end of the stroke of the suction bar.

12. Apparatus according to any one of claims 4 to 11, in which that one of the suction bars nearer to the filling nozzle is connected to the coupling mechanism by a U-shaped bridge member, which engages over the other suction bar, and by a vertical web fixed to the bridge member.

13. Apparatus according to claim 12, in which the guide rods are fixed to the vertical web.

14. A method of opening and applying prefabricated bags, particularly bags with side folds made of plastics or multi-ply papers, to the filling nozzle of a filling machine as claimed in claim 1 and substantially as hereinbefore described.

15. Apparatus for opening and applying prefabricated bags, particularly bags with side folds made of plastics or multi-ply paper, to the filling nozzle of a filling machine substantially as hereinbefore described and illustrated with reference to the accompanying drawings.