US3754371A

US3754371A - Method and apparatus for closing the mouths of flexible containers by twisting

Info

Publication number: US3754371A
Application number: US00257422A
Authority: US
Inventors: R Walker
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-05-26
Filing date: 1972-05-26
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28

Abstract

Flat mouths of containers of flexible material with contents in the body of the containers, are moved in one general direction between a mandrel rotatable about an axis and movable means for pressing the mouths against the mandrel, to shape the mouths on the mandrel, and then twist the mouth walls adjacent an end of the mandrel. Further movement of a container in such direction results in pulling of a twisted mouth from the mandrel.

Description

United States Patent Walker, III

[ 1 Aug. 28, 1973 METHOD AND APPARATUS FOR CLOSING THE MOUTHS OF FLEXIBLE CONTAINERS BY TWISTING [76] Inventor: Robert J. Walker, III, 92 River Dr.,

Jupiter, Fla.

[22] Filed: May 26, 1972 [21] Appl. No.: 257,422

[52] US. Cl 53/38, 53/181, 53/217, 53/227, 53/370, 229/87 B, 150/3 [51] Int. Cl B65b 7/00, B65b 7/12, B65b 51/00 [58} Field of Search 53/38, 181, 370, 53/217, 227; 229/87 B, 65; 150/3 56] References Cited UNITED STATES PATENTS 1,271,403 7/1918 Williams 53/38 Primary Examiner-Willie G. Abercrombie Attorney-Stanley Bialos {57] ABSTRACT Flat mouths of containers offlexible material with contents in the body of the containers, are moved in one general direction between a mandrel rotatable about an axis and movable means for pressing the mouths against the mandrel, to shape the mouths on the mandrel, and then twist the mouth walls adjacent an end of the mandrel. Further movement of a container in such direction results in pulling of a twisted mouth from the mandrel.

15 Claims, 9 Drawing Figures Patented Aug. 28, 1973 3,754,371

3 Sheets-Sheet l Patented Aug. 28, 1973 3,754,371

3 Sheets-Sheet 2 Patented Aug. 28, 1973 3 Sheets-Sheet 3 FIG.8

METHOD AND APPARATUS FOR CLOSING THE MOUTHS OF FLEXIBLE CONTAINERS BY TWISTING This invention relates to closing the mouths of containers made of flexible material by forming a twist of such mouth.

BACKGROUND OF THE INVENTION Flexible walled containers, such as those made of polyolefin film, usually polyethylene, are commonly employed in the packaging of food products, such as bread, as well as for the packaging of non-food products, such as soap bars. The containers may be in bag form with one end closed or in the form with one end folded and sealed. Product is packaged adjacent the sealed or closed container end while the mouth end of the container extends beyond the product. In many instances, such as bread packages, the mouth is closed by twisting the same and applying a clip thereto, or it may be twisted closed by strips of inelastic but bendable material forming part of the container walls, as is disclosed in the U.S. Pat. to Walker, No. 3,402,052, dated Sept. 17, 1968.

SUMMARY AND OBJECTS Summarizing the invention hereof, it embodies a special apparatus and method for closing the mouths of bags or other containers including wrappers, of the type related, by twisting the same in a continuous and rapid manner. For such purpose a succession of flexible walled bags or other tubular containers is continuously conveyed in spaced-apart relationship on a conveyor which has spaced-apart means adjacent one side for holding successive containers against twisting thereon. The container mouths are supported in flattened condi tion adjacent the opposite side of the conveyor; and are conveyed in one general direction between a rotatable mandrel and pressing means peripherally about the mandrel; the direction of movement of the containers being transverse to the axis of rotation of the mandrel.

Means is provided over the conveyor and adjacent the mandrel, in the form of an inclined ramp, to guide or direct the mouths between the mandrel and the pressing means while the facing surfaces of the mandrel and the pressing means are moved in the same general direction as the containers are conveyed. This results in each mouth being initially shaped on the mandrel in tubular or annular form, and then twisting of the mouth occurs adjacent an end of the mandrel. The facing surfaces of the mandrel and pressing means are desirably moved at approximately the same speed; and as the twist is being formed the mouth automatically becomes shortened in length, and is ultimately pulled off the mandrel by movement of the container by means of the conveyor.

Desirably, the containers are moved at a lesser speed than the speed of the aforementioned facing surfaces to enhance the twisting effect. Also, to effect conformation of the mouth on the mandrel, flow of gas, such as air, is directed against the sides of the mouth as it moves between the mandrel and the pressing means. Also, flow of gas is advantageously directed against sides of the mouth on the ramp to enhance guiding of the mouth into the nip between the mandrel and the pressing means.

The mandrel is desirably a brush having soft bristles which will not damage thin plastic film, such as those of a soft tooth brush, but other yieldable or resilient means may be employed such as sponge rubber or felt. The pressing means desirably comprises small diameter brushes of a similar character and of similar material, but may also be an endless belt having a portion peripherally looped about the mandrel.

From the preceding, it is seen that the invention has as its object, among others, the provision of an improved method and apparatus for effecting a twist closure of the mouths of flexible walled containers, which is of simple and economical construction, can effect the twisting operation on successive containers rapidly in a continuous uninterrupted manner (non intermittent), and which can be readily installed in a container packaging line. Other objects of the invention will become apparent from the following more detailed description and accompanying drawings, in which:

DESCRIPTION OF FIGURES FIG. 1 is a plan view of the apparatus illustrating the twisting of the mouths of containers having settable inelastic but bendable strips adhered to the container, of the type disclosed in the aforementioned Walker U.S. Pat., No. 3,402,052;

FIG. 2 is an isometric view of an end portion of such container closed by a twisted mouth in which the contents of the container is a loaf of bread;

FIGS. 3 through 6 are fragmentary isometric schematical views illustrating various stages of the operation, with parts being omitted to illustrate the operation more clearly;

FIG. 7 is a transverse vertical section of the apparatus; the plane of the section being indicated by line 7-7 in FIG. 8;

FIG. 8 is a longitudinal section taken in a plane indicated by a line 88 in FIG. 7; and

FIG. 9 is a schematic transverse sectional view of another embodiment of the apparatus.

DETAILED DESCRIPTION In the drawings, twisting of the unsealed mouths of bread packages is illustrated; the container 2 being desirably of conventional polyethylene film but may be of any other suitable flexible material which can be twisted closed. Opposite walls of the container are provided with metal foil strips 3 which enable mouth 4 to have a set twist when twisted as is described in the aforementioned Walker patent. Although strips are illustrated as extending the entire length of the container, they may extend part way from adjacent the mouth edge of the container. It is to be understood, however, that the twisting can be effected on other types of flexible containers, including wrappers, and a clip, adhesive strip, or other suitable retainer subse quently applied to the twisted mouth.

For the packaging of bread, the twisting apparatus is located at the end of the packaging line wherein the bread is placed in the container, and comprises an endless conveyor 6 of flexible belting or other suitable material provided with suitable means, such as spacedapart sets of fingers 7 adjacent one side edge of the conveyor, to hold and preclude twisting of the respective containers at the product content end. Conveyor 6 is moved continuously with an uninterrupted motion, in one general direction indicated by arrow D, toward the twisting apparatus indicated generally by T; the opposite walls of the open mouth 4 being adjacent each other and lying fiat adjacent the side of the container opposite to holding fingers 7.

One finger 7 of each container holding means is on the back side thereof with reference to the direction of movement of conveyor D, while the other is over the top of the container. As a result, the respective containers are firmly held against twisting as the bag mouths enter twisting mechanism T.

Twisting apparatus T comprises a center rotatable mandrel 8, and a plurality of pressing elements 9 pcripherally about the mandrel which are operated in a manner described hereinafter. For guiding or directing bag mouths 4 into the twisting apparatus, an inclined ramp 11 is provided over conveyor 6 adjacent mandrel 8, and extends to the mandrel between an adjacent pair of lower pressing elements 9, as can be seen from FIG. 7. This insures that the end of the respective bag mouths is introduced between the nip of mandrel 8 and the upper pressing element 9 appearing in FIG. 7. Mandrel 8 comprises a plurality of spaced-apart hubs 12 se cured fixedly to a rotatable drive tube 13, and to which brush bristles 14 of a soft character which will not damage plastic film, such as polyethylene, are secured. Each of pressing elements 9 comprises similar bristles secured to spaced-apart hubs l6 fixed to a rotatable shaft 17.

Referring to FIG. 7, and schematic views 3 through 6, it will be observed that mandrel 8 is preferably rotated in a clockwise direction (as seen in FIG. 7) while each of pressing elements 9 is rotated in the opposite or counter-clockwise direction, as is indicated by the direction arrows in FIG. 7. As a result, the facing surfaces of the mandrel and of the pressing elements 9 move in the same direction, which is the general direction of endless conveyor 6. These facing surfaces are desirably moved at substantially the same peripheral speed; and for a one turn twist, such peripheral speed is slightly greater (about percent) than the linear speed at which the containers are moved by conveyor 6. For forming a two turn twist, the peripheral speed is desirably also slightly greater than twice the linear speed of the conveyor.

Thus, as a container mouth 4 enters into the twisting apparatus, it is wound about mandrel 8 to form a tube; the diameter of the mandrel with reference to the width of mouth 4 and the peripheral speeds of the brushes being such that at least one substantially complete convolution is formed. In this connection, unless substantial overlapping of the container mouth is desired, the circumference of the mandrel should be slightly greater (about one-eighth inch) than one-half the circumference of the open end of the mouth.

With the brushes rotating in the directions described with reference to FIG. 7, the bag mouth will be directed upwardly about the mandrel as shown. However, the direction of both mandrel 8 and pressing brushes 9 may be reversed, thus directing the mouth downwardly to form an opposite twist if desired.

FIG. 5 illustrates partial tube formation shaped about the mandrel; the pressing elements 9 cooperating with mandrel 8 to effect such tube formation. Then because the container is held at the content end, twisting of the mouth occurs with simultaneous axial shortening of the mouth, as can be seen by comparison of P16. 6 with FIG. 5, with ultimate pulling of the twisted mouth endwise off of the mandrel to form a twist closure shown in FIG. 2. This twist may have a suitable retainer, such as a clip or adhesive band, applied thereto if so desired; and if the container does not have the aforementioned strips 3, a suitable retainer or anti-twist device, is desirably applied to hold the twisted mouth.

Means is provided to enhance guiding of the container mouth into the twisting apparatus comprising a tube 18 over ramp 11, having a plurality of spacedapart outlets 19 for directing flow of gas, such as air, against the sides of the mouths of the containers as they enter between pressing elements 9 and mandrel 8. Also, means is desirably provided to direct flow of gas against the sides of the respective mouths over the mandrel to enhance conformation or hugging of the mouth to the mandrel. For such purpose, an arcuate manifold 21 is provided in each of the spaces between the spaced-apart center brush structures and cooperating spaced-apart pressing elements. The manifold is provided with a plurality of outlets 22; and flow of air into the manifold 22 results in an air blast being directed against the mouths. To effect ready venting of the air from the twisting apparatus, the center brush hubs 12 are provided with axially extending passageway 23; and tubular drive shaft 13 has apertures 24 therein so that the air may be vented through vent fitting 26 (FIG. 8).

Any suitable means may be provided for continuously driving mandrel 8 and pressing elements 9. In the embodiment illustrated, such means comprises a variable speed motor 27 connected through coupling 28 to drive tubular shaft 13 joumalled in bearing walls 29. Driving gear 31 engages gears 32 secured to the respective rotatable shafts 17 for the pressing elements, which are also joumalled in bearing walls 29.

As was previously related, the peripheral speeds of the pressing elements 9 and mandrel 8 are desirably the same. However, they will vary depending upon the width of the container mouth, and the number of twists desired. The circumference of the mandrel depends upon how much overlap of the mouth is desired. If the mandrel has a circumference substantially less than the flattened width of the bag mouth, then the mouth will wrap itself with an overlap before being pulled away. If the circumference is substantially greater, there will be no overlap. As previously indicated, the circumference of the mandrel is preferably slightly greater than the width of the bag mouth (one-half the circumference of the open end of the mouth) so that there will be no substantial overlap. Pressing elements 9 should extend substantially 360 about the periphery of the mandrel to insure complete shaping of the bag mouth on the mandrel.

As a typical example, is employing the twisting apparatus in association with bread packaging machines having a capacity of about 50 loaves per minute, the loaves are spaced on conveyor 6 about 2 feet apart and are moved at the rate of about feet per minute. With a bag mouth width of about 8 inches (circumference 16 inches), a suitable mandrel circumference is about 8% inches, and pressing element circumference much less (about 2 inches in circumference), with a peripheral speed of their facing surfaces about feet per minute for about one 360 twist, and about 210 feet per minute for two 360 twists.

These factors are not critical and are given merely by way of example, as they will vary with the size of the container, and the number of twists desired. Although the mandrel and the pressing elements are desirably cylindrically shaped, they may be of other shape such as frusto conical.

In the FIG. 9 embodiment, mandrel 41 is substantially the same as that previously described, but the pressing means 42 comprises an endless belt having a cushioning bristle surface 43 which comes in contact with the container mouths; the belt being trained over suitable rollers 44 to provide a circular loop about mandrel 41 with its linear speed substantially the same as the peripheral speed of the mandrel.

Although in the embodiment illustrated, the twisting apparatus is employed with flexible containers or bags open at only one end of the container, in the case of flexible containers having mouths open at both ends, a like twisting apparatus can be positioned at the opposite side of the conveyor 6 for twisting and closing the opposite mouth about the container contents. In such event, the direction of rotation of the respective mandrels and pressing means, may be opposite to form twists in opposite directions about the container contents, thus decreasing the tendency for the contained material to turn in its position. The container need not be of tubular construction, as it may be a flexible wrapper sheet folded over the container contents, and both ends of the respective container wrappers may be twisted closed with a continuous uninterrupted motion.

I claim:

1. The method of closing the open mouth of a container of flexible material having opposite walls which comprises providing a mandrel rotatable about an axis, moving the container in one general direction transverse to said axis with the walls of the mouth in substantially flat condition, guiding said mouth walls to said mandrel, simultaneously rotating said mandrel and pressing said walls against said mandrel to shape said mouth on said mandrel and then twist said mouth on said mandrel, and removing the twisted mouth endwise from the mandrel.

2. The method of claim 1 wherein said pressing of said mouth walls against said mandrel is effected by providing movable pressing means about the periphery of said mandrel, and moving the facing surfaces of said mandrel and movable pressing means in the same direction.

3. The method of claim 2 wherein said facing surfaces of said movable pressing means and said mandrel are continuously moved at substantially the same speed.

4. The method of claim 1 wherein flow of gas is effected against said mouth over said mandrel to enhance conformation of the mouth to the mandrel.

5. The method of claim 4 wherein flow of gas is also effected against said mouth to enhance guiding of the mouth to said mandrel.

6. The method of claim 1 wherein a plurality of suc cessive containers is continuously moved in said general direction with an uninterrupted motion, and the mandrel is continuously rotated with an uninterrupted motion.

7. The method of claim 1 wherein the container has mouths open at both ends thereof, and a pair of mandrels is provided for twisting both mouths.

8. The method of claim 7 wherein the container is a wrapper sheet folded about contents within the wrappet and having opposite open ends, and a pair of man drels is provided for twisting both ends of the wrapper.

9. A container mouth twisting apparatus comprising a mandrel rotatable about an axis, movable means about said mandrel for pressing a container mouth against said mandrel, means for conveying such container mouth between said mandrel and said pressing means, and means for moving the facing surfaces of said mandrel and said pressing means in the same direction to shape said mouth on the mandrel and then twist the mouth walls adjacent an end of the mandrel.

10. The apparatus of claim 9 wherein said mandrel comprises a brush structure circular in cross section, the conveying means has means for holding containers in spaced-apart relationship with product therein, and with the container mouths adjacent a side of the conveying means, and an inclined ramp is provided over the conveying means to guide the mouths between said mandrel and said pressing means.

11. The apparatus of claim 9 wherein'said pressing means comprises a plurality of spaced-apart rotatable brush members about the periphery of said mandrel.

12. The apparatus of claim 9 wherein means is provided over said mandrel to direct flow of gas against the mouths of said containers on said mandrel.

13. The apparatus of claim 10 wherein means is provided over said mandrel to direct flow of gas against the mouths of said container on said mandrel, and means is provided adjacent said ramp to direct flow of gas against mouths on said ramp.

14. The apparatus of claim 9 wherein said pressing means comprises an endless belt having a loop peripherally about said mandrel.

15. A container mouth twisting apparatus comprising a mandrel rotatable about an axis, movable means about the periphery of said mandrel for pressing successive container mouths against said mandrel, a conveyor for said containers having spaced-apart means for holding ends of containers thereon and of a width to support the opposite open mouth ends in flat condition, said conveyor being continuously movable in a direction transverse to said mandrel axis to convey the containers toward the mandrel, means adjacent said mandrel and over said conveyor to guide the mouths between the mandrel and said pressing means, and means for continuously moving the facing surfaces of said mandrel and said pressing means in the same direction as the conveyor is moved to shape said mouths on the mandrel and then twist the mouth walls.

Claims

6. The method of claim 1 wherein a plurality of successive containers is continuously moved in said general direction with an uninterrupted motion, and the mandrel is continuously rotated with an uninterrupted motion.

8. The method of claim 7 wherein the container is a wrapper sheet folded about contents within the wrapper and having opposite open ends, and a pair of mandrels is provided for twisting both ends of the wrapper.

11. The apparatus of claim 9 wherein said pressing means comprises a plurality of spaced-apart rotatable brush members about the periphery of said mandrel.