Patent Application
20050119101
The present invention relates to a machine for forming and applying paper bag handles to bags.
Many forms of bags are used for packaging purposes or to carry shopping. These bags are easier to carry when provided with a pair of handles. Bags can be made of paper, foil material, plastic, fabric or the like, but it is particularly, though not necessarily exclusively, paper bags to which the present invention is directed and the means of forming and applying paper handles to these bags.
Paper bags can be first manufactured by a bag making machine without handles by cutting blanks of any predetermined size from paper webs followed by folding and bonding the blanks. The bags leave the machine, flat and are usually collected and stored in a hopper for supply to a handle forming and application machine which attaches handles to the outside of preformed bags. This provides bags with external handles.
Alternatively, bags with internal handles can be made (unless produced by hand) by first forming the handles with the bag forming and application machine and then attaching them to the sides of a bag making stock which is subsequently made by the bag making machine into individual bags having handles on the inside faces.
Examples of handle forming and application machines are described in, e.g.: DE 1152 602, U.S. Pat. No. 5,298,007, U.S. Pat. No. 5,609,556, U.S. Pat. No. 2,625,862 and U.S. Pat. No. 2,689,506.
The following is a description of an example handle forming and application machine, known as the Windmöller & Hölscher T1441 Handler, that is well known and in use at the time of the present invention. The Windmöller & Hölscher T1441 Handler is an example of a handle application machine for forming bags with external handles.
A paper strip 9 from one of the reels is fed first to a paper strip creaser 1, which imparts two parallel longitudinal creases along the length of the paper strip 9, as shown in
The layered strip of paper 9′, once cured, is then cut, across its width, and separated by an elliptical gear 4 into smaller individual handle lengths 15 (see
The handles 17 formed are of general U-shape with the legs of the U 18 being attached to the preformed bag and the bight of the U 19 for holding the bag when in use. The vacuum mechanical gripper 16 of the prior art is effectively a station either side of the former drum 11 and consists of two parts: the mechanical gripper part 20 and the vacuum gripper part 21. The mechanical gripper part 20 holds each handle length 15 to the former drum 11 at two places, as shown, both of which are inside the bight portion 19 of the substantially U-shaped handle. The vacuum gripper part 21 maintains the legs 18 of the handle 17 in position once they have been folded over as described below.
Referring to
Referring back to
The handle length 15, having been dragged through a creaser 22 and the handle shaping former plate 23, is now of substantially U-shaped form. The mechanical gripper part 20 of the vacuum mechanical gripper 16 continues to grasp the bight of the U 19, while the legs of the U 18 are maintained in their now folded over position by the vacuum gripper part 21, which pulls the legs 18 of the U-shaped handle 17 towards the former drum 11.
The U-shaped handle 17 is transferred onto a paste application drum 24, which utilizes the same type of vacuum mechanical gripper 16 as the former drum 11. The paste application drum 24 applies cold adhesive, such as glue, to the peripheral attachment portions 25 (see
Simultaneously, paper from the other reel 29 is processed in the same way along a parallel path comprising an identical former drum 11 and paste application drum 24. Thus, at the attachment stage a substantially U-shaped handle 17 is being applied simultaneously to the opposite outside face of the preformed bag 26.
Referring back to
The preformed bags 26 are conveyed between a nip formed by upper and lower paste application drums 30, where U-shaped handles 17 are bonded to opposite outside faces of the preformed bag 26 by the above described processes.
The preformed bags 26 with handles 17, can then be transferred out of the machine into a collection tray.
The above described Prior Art paper bag handle forming and application machine suffers from many drawbacks, some of which the present invention aims to resolve.
One difficulty encountered in running handle attaching machines of the prior art is that the speed of the former drum and paste application drum are limited by the efficiency of the vacuum of the vacuum mechanical grippers. The speed may also suffer as a consequence of the multiple handle transfers. The machines of the prior art are rated at 150 bags per minute, with the normal operating figure being just 120 bags per minute. However, the prior art bag making machine is capable of supplying bags at 200 to 300 bags per minute meaning that the paper bag handle attaching machine is not running at its full potential. Hence, for optimum machine operation, the handle forming and application machine could be run at a faster speed, closer to the maximum speed of the bag feeder or the bag making stock feeder. The vacuum has a further drawback of having a large energy consumption.
The present invention provides an apparatus for attaching paper handles to bags or bag making material, comprising: a paper source for supplying paper; a first transverse cutting means for cutting the paper across its width into paper segments; a first handle forming and attachment unit for forming the paper segments from the first transverse cutting means into substantially U-shaped handles and attaching the substantially U-shaped handles to a first surface of bags or bag making material; paper segment gripping means for holding a paper segment to the handle forming and attachment unit; and a mechanical guide means extending over at least a portion of the first handle forming and attachment unit for maintaining the substantial U-shape of the handles.
A corresponding method for manufacturing paper handles is also provided.
The method and apparatus of this aspect of the invention provides a means of gripping the handle segments to the handle forming and attachment unit without the use of vacuum.
This will allow the machine to operate at speeds not limited by the efficiency of any vacuum and improve the energy efficiency of the machine.
In prior art handles, each handle is transferred four times: to the transfer gripper; to the vacuum mechanical gripper at the former drum; to the paste application drum and finally to the preformed bag. Each transfer increases the risk and incidence of a transfer failure, which will reduce the handle application efficiency of the machine and would result in paper jams which take time to fix.
In a preferred embodiment, the invention provides an apparatus for attaching paper handles to bags or bag making material, wherein feeding means for feeding the paper segments to the handle forming and attachment unit impart sufficient momentum to the paper segment to transfer the paper segment to the first handle forming and attachment unit by means of the momentum imparted to it. Also in a preferred embodiment, the paper segment is held by the gripping means in use during forming into a substantially U-shaped handle and wherein said gripping means releases the handle for attachment to the bag or bag making material.
This preferred embodiment of the invention reduces the number of transfers in transferring the paper to the handle forming and attachment unit and during the handle forming and attachment process as compared to the Prior Art. Less transfers means a lower risk of transfer failure.
The ply of the paper is therefore maintained from paper supply to the handle forming and attachment units.
A paper strip having a basis weight of 375 grams per square metre (gsm), as is conventionally used for making handles in the machine described above, is far greater than what is usually needed to hold the bag for normal applications. The paper layering or folding (as described above in relation to
Another preferred embodiment of the invention provides an apparatus for attaching paper handles to bags or bag making material, wherein the paper from the paper source is greater than 250 gsm.
The paper for making the handles is not creased and folded in the longitudinal direction and glued in place to form thicker paper. A lower basis weight paper can, therefore, be used, which is more suitable for its eventual use and more cost effective. Glue is obviously no longer needed to hold the folds of the layered strip of paper into position, so production costs are reduced.
The use of two reels of paper strip in the Prior Art, as the starting stock for forming the handles, requires two reel changes when the need arises. This can prove both time consuming and troublesome.
According to a further preferred embodiment, there is provided an apparatus for attaching paper handles to bags or bag making material, including a longitudinal cutting means for cutting the paper along its length into a plurality of paper strips; a second transverse cutting means for cutting a paper strip across its width into paper segments; and a second handle forming and attachment unit for forming paper segments from the second transverse cutting means into a substantially U-shaped handle and attaching the substantially U-shaped handle to a second surface of the bag or bag making material; and feeding means for feeding the paper strips from the longitudinal cutting means either to the first transverse cutting means or to the second transverse cutting means.
This embodiment of the invention provides a machine with only a single source of paper, meaning less paper is required to produce a pair of handles than in the Prior Art and less time is required for the changeover of the paper source.
In the prior art, the gripper drum, when removing bags from the hopper, sometimes has a tendency to take more than one bag at a time. Any extra bags will serve to jam up the former drum. Also, an operator is required on either end of the machine, feeding the bags in and taking them off, with the operator feeding the bags also monitoring for double bag feed. When bags jam in the handle forming and application machine, they usually knock out the timing of the conveyor belts feeding the bags to the former drums. Also, every time a bag jams in the machine it may knock out the alignment of some or all of the parts of the former drum such as the creaser, the shaping of the handles against the former plate, or even the vacuum mechanical grippers. These bag jams can take an excessive time to fix. The problem of multiple simultaneous bag feed not only involves the extra labour costs of having the bag feeder monitored, but also involves machine downtime and the need for maintenance when a jam occurs. Furthermore, when the size of the preformed bags are changed, the grippers and the conveyor side walls require changing. Hence, both the hopper and the conveyors need adjusting to fit the bag being used.
Another preferred embodiment of the invention provides an apparatus for attaching paper handles to bags or bag making material, including a transport means for feeding bags or bag making material from a bag or bag making material supply unit, said supply unit for supplying bags or bag making material to the first handle forming and attachment unit, wherein the apparatus further comprises a bag gripping means for removing the bags or bag making material from the bag supply unit and an air under pressure supply for pushing the bags or bag making material to the transport meansthe bags are pushed from the bag supply unit to the transport means using air under pressure.
This preferred embodiment of the invention can be used in combination with a handle application machine of the prior art, but is preferably used with the apparatus provided by the present invention.
This embodiment provides a more reliable bag supply, with the incidence of multiple simultaneous bag feed being reduced compared to that of the Prior Art.
Maintenance of the handle application machines of the Prior Art can take up to two hours because of the present structure of the machines. The frequency of breakdowns due to multiple simultaneous bag feeds and the length of each maintenance time reduce the productive output of the machine.
Another preferred embodiment of the invention provides an apparatus for attaching paper handles to bags or bag making material, including side access means for accessing the internal components of the apparatus from at least one side of the machine.
This embodiment of the invention provides a side access means, which should considerably reduce maintenance time, especially when fixing bag jams.
In a preferred embodiment of the invention, a method and apparatus is provided wherein the paper is cut along its width into paper segments which are transferred to the handle forming and attachment unit and decelerated and appropriately positioned to allow gripping by the gripping means, with this decelerating and positioning preferably occurring by means of a brush.
Another preferred method and apparatus of the invention provides cutting means for cutting the paper along its width into paper segments and a gripping means for gripping the paper segments to the handle forming and attachment unit during handle forming, application of handle attaching means to the substantially U-shaped handle and releasing of the paper segment by the gripping means for attachment to a bag or bag making material of the substantially U-shaped handle.
In a further preferred method and apparatus of the invention there is provided a bag supply unit for the supply of bags and a transport means for feeding the bags from the bag supply unit to the handle forming and attachment unit, wherein the bag supply unit comprises a bag container and a bag gripping means and wherein a bag is removed from the bag container in a direction not in the direction of movement of the transport means and wherein air under pressure pushes the removed bag to the transport means. Preferably, the bag passes through a brush during transferring from the bag supply unit to the transport means.
In another preferred method and apparatus of the invention there is provided a removable bag supply unit.
The present invention provides a handle forming and application machine which solves the above mentioned problems.
Preferred embodiments of the invention will now be described by way of example only and with reference to the drawings.
As shown in
An alternative to the above described machine is to use bag making stock instead of preformed bags 26. The handles 17 will be manufactured first, in accordance with the methods and apparatus of the present invention, and attached to the bag making material. The bag manufacturing machine will then form the bag making material into individual bags. The present invention can, therefore, produce bags with internal or external handles 17.
In a preferred embodiment of the present invention, the source of the paper strip 35 is a single reel 32 of 38 mm wide paper held on a turret stand 37. The turret stand 37 will allow quick changeover when the need occurs. The paper is pulled from the reel 32 and fed, by conventional means such as rollers, to a cutter 36 for dividing the paper strip 35 roughly down the middle in a longitudinal direction. This provides a paper strip 35 for each former drum 33, while only a single reel source 32 is used. Each paper strip 35 is then fed to a respective former drum 33 for handle forming and application to different sides of the preformed paper bags 26 or bag making stock.
The paper strips 35 are provided to the former drums 33 without any creasing, folding or layering and without gluing the outer portions 12, 13, (see
The layering of the paper is not required because the handle lengths 15 are not treated as roughly in the later stages of the handle forming and application process of the invention as they are in the prior art. This overall reduction in processing steps and wear of the paper means a lower basis weight paper of preferably between about 250 to about 280 gsm may be provided at the former drum 33. However, the exact basis weights used can obviously be altered to the specific requirements of the handle 17 ultimately produced. The paper strip 35 can be thinner in width than is conventional, as although it is being cut into two paper strips 35, it is not being folded into three layers, as in the Prior Art. In its preferred forms, the present invention, therefore, uses less paper than is conventional.
One example of the dimensions of the paper strip 35 used is 38 mm in width at its source, before being cut into two paper strips 35 of 19 mm in width each. Again, any specific width paper strip 35 may be used to suit the needs of the handles 17 eventually produced.
The paper strip 35 requires fewer processing steps before being fed to the former drum 33 compared to the prior art, requiring a less complicated processing apparatus. Furthermore, there is no need for a constant supply of glue to the paper strip 35. Another advantage is that the paper strip 35 provided to the former drum 33 has not been damaged by any creasing step and as it is, in its preferred form, only single-ply, it will be more easily manipulated when folding into substantially U-shaped handles 17.
The paper strip 35 is, as is conventional, cut across its width and separated into separate handle lengths 15 (shown in
The handle lengths 15 are transferred to the surface of the former drum 33. The cylindrically shaped former drum 33 accepts the incoming handle lengths 15 across its width. The former drum 33 is rotating in a plane perpendicular to the direction of movement of the incoming handle lengths 15, such that if viewed in the line of the direction of movement of the incoming handle lengths 15, the handle lengths 15, once positioned on the rotating former drum 33, would be travelling either left or right depending on whether the drum was rotating clockwise or anticlockwise respectively. Each handle length 15, once positioned on the former drum 33 is grasped by a spring-loaded gripper 38 (shown in
As shown in
With reference to
This results in a substantially U-shaped handle 17, with the parallel legs 18 of the U being the result of the fold over of the two outside parts 18 of the creased handle length 15. The bight of the U 19 achieved from this process is the portion of the handle 17 to be held when in use.
Any creasing and folding means known in the art to produce such handles 17 may be used. Furthermore, the exact shape of the handles 17 is not essential as long as it performs the purpose of providing a handle 17 to be held when carrying a bag 26.
The hot melt applicator 41 applies hot melt adhesive to the attachment portions 25 of the legs 18 of the U-shaped handles 17, as shown in
The spring loaded gripper 38 is finally forced to release the handle 17 by a cam at the centre of the former drum when the handle is to be applied to the preformed bags 26 or the bag making stock.
Thus, in the preferred embodiment, there are only two transfers of each handle 17: to the spring-loaded gripper 28 and to the preformed bags 26 or the bag making stock. This is an improvement over the prior art where four transfers are generally employed. This improvement reduces the risk of transfer failures.
Preferably, a raised rail guide 43 extends around a portion, or all, of the former drum 33 to maintain the U-shape of the handles 17 once the legs 18 have been folded into position. As the U-shaped handles 17 rotate on the former drum 33 for hot melt application and attachment, the foldover portions 18 of the handles 17 are maintained in this state by means of the raised guide rail 43 and without the need for vacuum suction pulling the legs 18 toward the drum. This, in combination with the spring-loaded gripper 38, eliminates the need for any vacuum in the machine, as is desirable. The machine speed is therefore not limited by the efficiency of any vacuum. This along with other improvements in the operation of the handle forming and application machine, as describe above, makes the machine capable of running at a speed comparable to the rate of the bag manufacturing machine, e.g. 280 bags per minute, and is preferably geared to operate at that speed. The lack of vacuum should also reduce the energy consumption of this part of the machine, as compared to the prior art.
Although the present description describes an embodiment in which two handles are made at a time, it is possible that the invention could be incorporated into a machine which manufactures more than two handles in parallel. In such a machine, for example, more than two parallel paths of drums could be provided. Alternatively, a number of equally spaced spring loaded grippers 38 may be disposed over the circumference of the former drum 33 so that a plurality of preformed bags 26 can be processed during any one revolution of the former drum 33. Preferably, as is shown in
With reference to
In the case where no hopper is used and the bag making machine and the handle attaching machine are linked, either preformed bags are fed to the handle attaching machine or paper bag making stock is fed. Either way, the handle attaching machine is, preferably, run at the same speed as the top speed, or near the top speed, of the bag manufacturing machine, e. g. 200 to 300 bags per minute. When bag making stock is fed to the handle attaching machine, the basic design of the handle attaching machine will be the same as in the handle attaching machine being fed with preformed bags 26. One minor adjustment that would need to be made is in the mechanism for transferring the handles 17 to the bag making stock. This can be any standard transfer unit for attaching handles 17 to bag making stock, preferably, in combination with the handle attaching apparatus already disclosed.
In the case where a hopper 34 is used, the preformed bags 26 are pulled down and backwards out of the hopper 34 by a gripper, relative to the direction of movement of the conveyor delivering the preformed paper bags 26 to the former drum 33. A jet of air pushes a single preformed bag 26 forwards onto a pusher 44 on the chain feed. The preformed bags 26 are generally deployed onto the pusher 44 on the chain feed with the base of the preformed bag 26 leading. Another brush is used either to ensure that the gripper only removes one preformed bag 26 at a time from the hopper 34 or the jet of air only forces one preformed bag 26 onto the pusher 44 at a time. By pulling the preformed bags 26 out of the hopper 34 backwards, multiple simultaneous bag feed would not necessarily result in more than one preformed bag being fed onto the chain pusher 44, as this is done in a separate step by the jet of air. These features, in combination with the use of a brush to ensure only a single preformed bag 26 feed, reduce the risk of multiple simultaneous bag feed as compared to the bag supply conventionally used to supply preformed bags 26 from a hopper 34.
This design of bag supply allows the size of the paper bags to be changed without altering the conveyor walls as the preformed bag 26 is just being pushed along the conveyor. The removability of the hopper 34 has the further advantage that when bag size is changed, the hopper 34 is simply replaced. Thus, bag size changes can be implemented more quickly and more easily as compared with the prior art.
Fewer occurrences of multiple simultaneous paper bag feed will reduce the incidence of machine jam, especially at the former drums 33. This will reduce the costs incurred during machine downtime as compared to the prior art machines.
Preformed bags 26 or bag making stock are fed from the bag supply to the nip between the two former drums 33 where handles 17 are applied to either side of the preformed bag 26. The preformed bags or bag making stock are carried to the former drums 26 by conventional transport means, such as belt-driven conveyors. In a preferred embodiment of the invention, the side of the machine may be removable or openable, and is preferably hinged to allow access to the internal components of the machine, such as the preformed bag or bag making stock feeding conveyors, the former drum 33 and the hopper 34. This way, should a chain link of the chain drive of the preformed bag or bag making stock feeding conveyor break, or a jam of any other parts of the handle forming and application machine, such as the former drum 33 or the hopper 34, occur, the source of the problem can be easily identified and accessed by maintenance crews. It is estimated that breakdown should take only 15 minutes to fix and less than 5 minutes for most breakdowns. Thus, not only is the frequency of machine breakdowns reduced by the present invention, so is the maintenance time required for such breakdowns.
The bags, with handles applied, are then collected in the usual manner.
The present disclosure provides numerous new features and advantages over conventional paper bag handle forming and application machines and methods of applying handles, as will be readily apparent to one skilled in the art upon reading the description and the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0319102.0 | Aug 2003 | GB | national |
