NZ316880A

NZ316880A - Transferring bags from stack to filling machine, grippers use adhesive blobs to grip bags

Info

Publication number: NZ316880A
Application number: NZ316880A
Authority: NZ
Inventors: Markus Nutzi
Original assignee: Buehler Ag Geb
Priority date: 1995-09-29
Filing date: 1996-09-23
Publication date: 1999-04-29
Also published as: KR100457805B1; WO1997012810A1; RU2174486C2; ES2142607T3; DE59603994D1; CN1198140A; AU709660B2; CN1075014C; AU6922296A; KR19990008374A; EP0852553B1; BR9610622A; ATE187941T1; EP0852553A1

Abstract

The invention concerns a method and device for automatically suspending sacks, in particular also for gripping and opening sacks. The invention can preferably be used for air-permeable or woven open sacks. The object of the invention is to enable sacks made of such materials to be simply and reliably automatically gripped, opened and suspended on a sack filler neck. This object is achieved in that gripper pegs (2) of known gripper devices (1) are provided with self-renewing adhesive bonding points (6).

Description

<div class="application article clearfix" id="description"> % New Zealand No. 316880 International No. PCT/CH96/00327 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 29.09.1995; Complete Specification Filed: 23.09.1996 Classification:^) B65B43/16.30; B65H3/20 Publication date: 29 April 1999 Journal No. : 1439 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Device for automatically suspending sacks Name, address and nationality of applicant(s) as in international application form: BUHLER AG, Patentabteilung, CH-9240, Uzwil, Switzerland 3168 Device for automatically suspending sacks The invention relates to a method for automatically suspending sacks according to the preamble of claim 1 and to a device for this purpose. It relates, in particular, to the gripping and opening of open sacks, preferably those made of woven, air-permeable materials, in order to suspend them on a sack filler neck and then to f^ll them. It is known automatically to grip and open sacks in order subsequently to suspend them automatically on a sack filler neck and to fill them. EP-B-293615 describes a device for filling and closing gusseted paper sacks. Individual sacks are removed from a package by vacuum devices and driven between vacuum rails. These vacuum l-ails are then driven apart to a stop. The sack is opened by the vacuum rails until pivotal external grippers are able to press the outer folds against opposing holders. The pre-opened sack is then moved by means of a carriage into a filling station beneath a stationary filling hopper and is subsequently gripped by pivotal grippers. The carriage is capable of travelling back during the filling process in order to receive a new sack. EP-A-522110 describes a similar solution for automatic sack suspension. A sack is again removed from the stack by vacuum grippers, pre-opened, grasped by sack-opening claws, opened and simultaneously guided via a double lever system to a sack filler neck and automatically clamped. The sack to be opened is actually "pulled across the knee" to allow suitable deformation and pre-opening of the sack. These solutions with vacuum grippers are only suitable for sacks made of materials which are impermeable to air. They also demand additional expenditure of energy. 316880 2/8 These solutions with vacuum grippers, such as for example also described in WO 92/12900, are only suitable for sacks made of materials which are impermeable to air. They also demand additional expenditure of energy. Mechanical grippers for these handling operations are technically complicated, susceptible to breakdown and expensive. A device for gripping individual, flat fabric parts, preferably made of plastic, is also known according to European application 187 351. Raising or removing of individual fabric parts or fabric sacks from a stack should thus take place by means of brushes. Each brush can be pressed against the fabric to be gripped using its bristles, and can be moved back and forth in a direction transverse to the extension of the bristles using its bristles which are engaging into the fabric part. The particular fabric part gripped by the brushes is thus stretched in one direction of movement. The bristles release the fabric part again in the other direction of movement of the brushes. The device can thus also be used for opening sacks. A further document, French application 2 107 176, shows a device for roller application of materials on textile webs or the like. German Auslegeschrift 1 285 381 describes a device for gripping film bags by means of grippers, wherein a bag to be opened is gripped on the upper and on the lower side by in each case two rollers provided with adhesive strips, to then open it by moving the gripperc apart. The device is comparatively complicated. German Offenlegungsschrift l 486 061 describes a similar arrangement for opening and guiding film bags by means of I INTELLECTUAL"^1? ^lfRTY"^Ficn 316880 2a/8 grippers. The grippers contain gripper parts which can be moved with respect to one another and are provided with an adhesive agent and act on the outer sides of the bag in the region of their opening. A device for cancelling adhesion is assigned in each case to the gripper parts, and is arranged so that it is a comb which can be pivoted against the adhering bag surface. The arrangement is constructed in mechanically complicated manner and requires manual operational expenditure. Furthermore, a device for opening film bags is also known according to British application 2 010 213 and contains gripping elements. These gripping elements are coated with nylon fabric which in turn has hook-like elements and at the same time is impregnated with a gelatine-like material. The last-mentioned devices are only used for air-impermeable films. It is accordingly the object of the invention to provide a method and a device for automatically suspending sacks which allows sacks made of different materials to be reliably gripped and oprned using simple means, to enable them to be suspended on a sack filler neck. This object is achieved with the features of the characterising part of the claim. The invention is based on known methods of creating adhesive bonds, such means being used instead of vacuum grippers and the like. For gripping and opening, in particular, air-permeable, open, empty sacks, temporarily adhesive bonds are produced between sack and gripping element. This allows the gripping elements to be released from the sack material without difficulty after suspending and clamping the open sack on the sack filler 1 316880 2b/8 neck, the sack material rarely or never being damaged owing to the selection of suitable take-off movements and speeds. Bonding points which are self-renewing on the tool side such as hot-melt adhesives, adhesive sticks and roller adhesives and the like and optionally velcro strips are particularly suitable. Glue or adhesive can be applied in various ways with regard to actual application and also with regard to the removal of the gripping device from the adhesive or sack material. 1 31688 The advantage of the solution according to the invention resides mainly in the fact that, in contract t,o vacuum grippers, a wide variety of sack materials, including woven, air-permeable sack materials, can be handled and the gripping elements themselves can be simpler in design. In particular, a pneumatic system is not required. Various known methods of picking up and fixing sacks from a stack or magazine are conceivable, for example according to DE-A-4116311, EP-A-522110 or WO 95/09765. An embodiment of the solution according to the invention is described in detail hereinafter with reference to drawings. Figure 1 is a basic diagram of the solution according to the invention. Figure 2 shows a possible embodiment of parts of the gripping arrangement. The device for automatically suspending sacks consists of a gripping arrangement 1 with gripping pegs 2. Depending on the pick-up position of the empty sacks 3, the gripping arrangement 1 can perform any suspension movement onto a sack filler neck 4 by means of known handling elements of the type described, for example, in EP-A-522110. The sack filler neck 4 is provided with sack clamps 5 also in a known manner. High productivity can be obtained with a simple design. The gripping pegs 2 are equipped with self- renewing bonding points 6. In the embodiment, these are hot-melt spots which adhere to the gripping peg 2 more lightly than to the material of the sack 3. Operation of the device according to the invention can be described as follows: 31688 4 An empty sack 3 is removed by means of a pair of gripping pegs 2 from a magazine not shown in detail in the horizontal position. The two gripping pegs are provided with hot-melt spots as bonding points 6. When the sack 3 is gripped., the sack material adhex'es to the bonding points 6 and the sack 3 is opened merely by driving apart the. gripping pegs 2, until it has been moved appropriately beneath the sack filler neck 4 and is suspended thereon and fastened by sack clamps 5. The sack 3 px~ei:erably rests with its base on a conveyor belt or the like. These gripping pegs 2 can act on the sack 3 simultaneously and in succession in order to grasp and open the sack 3. After the sack 3 has been clamped on the sack filler neck 4, the hot-melt spots are torn from the gripping pegs 2 by opening the gripping pegs 2 and remain on the sack material. The sack 3 is then filled in the conventional manner and subsequently sealed. The hot-melt spots could just as harmlessly be torn from the sack material, but the bonding points 6 of the gripping pegs would have to be cleaned in this case . The hot-melt spots are applied as self- renewing bonding points 6 by means of conventional applicators (for example nozzle application) before the gripping of a sack 3 or are arranged within the gripping peg 2 in a forward-feed and heating device. The gripping peg 2 can optionally also comprise a cooler to allow rapid cooling of the hot-melt spots. According to a further variation, the gripping peg 2 can consist of a reciprocating bonding plunger 21 guided in a moulding tube 22 which also reciprocates. The spot of adhesive for the bonding point 6 is applied by a nozzle 23, rapid cooling being permitted. It is also possible to supply the adhesive via a bore in the bonding plunger 21, which is more reliable but more complex. As described, the bonding plunger 21 adheres via the bonding point 6 on the sack 1 and % 5 31688 can be separated from the sack 1 by means of the reciprocating moulding tube 22. In a further variation, the gripping pegs 2 could also remain on the clamped sack in order to guide the filled sack 3 after release from the sack filler neck 4 on a conveyor belt into a closure station. Other methods of creating the bonding points 6 include feed-controlled adhesive sticks or adhesive rollers or also known velcro strips. However, the latter tend to become soiled and are not applicable to all materials. With various known methods, the sack 3 or the entire stack of sacks 7 can be fixed in its position to allow reliable isolation, opening and movement of the sack 1. This can be achieved by a counter-holder to an upper gripping peg 2' or also by fixing the stack of sacks laterally in front of the point of removal 8. This can be achieved industrially by means of a folding holding-down device. Li 1 2 3 4 5 6 7 8 21 22 23 316880 6 of reference numerals gripping arrangement gripping peg sack sack filler neck sack clamp bonding point stack of sacks removal point bonding plunger moulding tube nozzle </div>

Claims

<div class="application article clearfix printTableText" id="claims"> •^6880 WHAT WE CLAIM IS : -

1. Method for automatically suspending sacks, in particular for gripping and opening empty sacks and suspending and clamping them on a sack filler neck using known gripping and clamping mechanisms, the supply and opening of the sacks being effected by known feeding movements, and the sack being isolated and temporarily acting bonding points being applied in succession to the sack and gripping arrangements temporarily adhering to the sack in order to grip it, to open it and to supply it to the sack filler neck, and in that the temporary bond between the gripping arrangement and the sack is released once the sack has been clamped to the sack filler neck, wherein it is used to grip and open sacks made of air-permeable materials.

2. Method according to claim 1, characterised in that the air-permeable materials are woven plastics, cotton or jute fabric and the like.

3. Device for automatically suspending sacks according to the method of claim 1, in particular for gripping and opening empty sacks and suspending and clamping them on a sack filler neck using known gripping and clamping mechanisms, wherein the device has a gripping arrangement comprising gripping pegs which oppose one another in pairs, and the gripping pegs comprising bonding points which have a temporary adhesive action, wherein the bonding points are hot-melt spots which are applied in each case and have lower adhesion to the gripping peg than to the material of the sack. intellectual property office of n.z. 16 MAR 1999 316880 8

4. Device according to claim 3, characterised in that the bonding points are feed-controlled.

5. Method according to claim 1, substantially as herein described with reference to Figure 1 or Figure 2.

6. Method according to claim 1 or claim 2, substantially as herein described.

7. Device for automatically suspending sacks, substantially as herein described with reference to Figure 1 or Figure 2.

8. Device according to claim 3 or claim 4, substantially as herein described. intellectual property office OF N.Z. 16 MAR 1999 .RECEIVED </div>