US2971311A - Apparatus for treatment of bag mouths and the like - Google Patents

Description

Feb. 14, 1961 E. E. MESSMER APPARATUS FOR TREATMENT OF BAG MOUTHS AND THE LIKE Filed April 4, 1960 2 Sheets-Sheet 1 INVENTOR. EDWIN E. MESSMER f1 ATiOPA/I? v m N- in.

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APPARATUS FOR TREATMENT OF BAG MOUTHS AND THE LIKE Filed April 4, 1960 2 Sheets-Sheet 2 INVENTOR: EDWIN E. MESSMER United rates APPARATUS FOR TREATMENT OF BAG MGUTHS AND THE LEG Edwin E. Messmer, Roslyn Heights, N.Y., assignor to Amsco Packaging Machinery, Inc., Long island City, N.Y., a corporation of New York Filed Apr. 4, 1960, Ser. No. 19,955

Claims. (Cl. 53-373) This invention relates generally to heat-sealing machines, and has particular reference to the type of apparatus in which a succession of articles to be heattreated are fed to and past a sealing station.

It is a general object of the invention to provide such a machine with improved means operative upon each successive article, just prior to its subjection to treatment, to condition it in a manner which insures proper coaction between the heating instrument and the elements to which the heatis to be applied.

The improved apparatus is primarily intended for operation upon superposed plies of plastic material which are to be pressed together to form a seal, as exemplified by the opposed walls of the mouth of a bag composed of polyethylene or the like, containing merchandise. The features of the invention will therefore be described in connection with a bag-mouth sealing machine, although the invention is not in every respect restricted to any such specific use.

The bags upon which the present apparatus is intended to operate are usually of the type comprising two opposed side walls joined along three edges, but unconnected along a fourth edge in order to form a bag mouth. These bags are usually fabricated from thin heat-sealable material such as polyethylene, which to a large extent lacks stiffness, and hence is diflicult to handle. In commercial practice, such a bag is usually filled with merchandise and is then immediately ready for the sealing operation. However, since the merchandise generally does not completely till the bag, an excess of bag material is present between the mouth opening and the merchandise in the bag. For convenience, this excess material will hereinafter be referred to as the bag mouth while the filled region of the bag will be referred to as the bag body.

.In subjecting such bags to a heat sealing operation, they are usually moved, in succession, by means of a pair of bolts which frictionally engage the body of each bag between them and thus transport it to and past the sealing station. The heat applying equipment may be of known character, such as a pair of tangentially-arranged rollers as shown in Patent No. 2,913,863, at least one of which has a heated edge. The rollers can serve not only to join the two sides of the bag mouth and thus seal the bag, but also to sever from the bag body the excess material lying beyond the sealed area. Often it is desirable that the heating elements coact with the bag mouth along a relatively thin line closely adjacent to the merchandise, whereby the sealing operation forms a fourth sealed edge on the bag to produce a completely closed package which snugly encloses the merchandise within it.

A difficulty which commonly arises in sealing the bag mouth is due to the limpness of the material from which the bag is fabricated. As the bag mouth enters the bite of the sealing rollers, it tends to be retarded because it is unsupported, and hence as the bag continues to move, the region to be sealed is likely to become wrinkled.

Zfiilfifl Patented Fain. 14, 196i.

As a result, not only is a poor seal formed, but the final package has an unsightly appearance.

It is an object of the present invention to alleviate this and other difiiculties, and toward that end means are provided for maintaining the bag mouth in taut condition as it enters between the heat sealing rollers. In this way, the sides of the bag are so conditioned for the sealing operation, that the bag is prevented from wrinkiing, thus insuring a proper seal.

The preferred embodiment of the invention comprises a pair of elongated brushing instruments, each of which is constantly rotated about an axis parallel and adjacent to the path of movement of the bags through the sealing apparatus, the axes being arranged on opposite sides of this path, respectively. Each of the instruments is provided with brushing elements which preferably are yieldable members projecting radially therefrom. The brushing instruments have their axes so spaced that as the instruments rotate the tips of the brushing elements just meet. Furthermore, the members are rotated in opposite directions so that as the brushing elements approach one another, they are moving in a direction away from the body of the bag. As a result, when the bag reaches the brushing instrument in its travel toward the sealing rollers, the bag mouth is drawn between the brushing members and pulled in a direction away from the body of the bag. In this way, the side walls forming the bag mouth are pulled taut thus preventing the sides from wrinkling during the sealing operation.

It is a further object of the invention to provide means adjacent to each brushing instrument to prevent the bag mouth from being drawn around either of the instruments, since otherwise the beneficial effect of the brushing would be lost and, worse, there might be damage to the apparatus.

Other objects and advantages of the present invention will be apparent from the following description.

In the drawings:

Fig. 1 is a fragmentary plan view of a heat-sealing apparatus provided with an illustrative embodiment of the present invention;

Fig. 2 is a side elevational view of the apparatus shown in Fig. 1;

Fig. 3 is a cross-sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is a cross-sectional view taken on line 44 of Fig. 1;

Fig. 5 is a fragmentary perspective view of one of the brushing members or" the present invention;

Fig. 6 is a cross-sectional view taken on line 66 of Fig. 1; and

Fig. 7 is a perspective view of a sealed bag contain ing merchandise as it leaves the heat sealing apparatus.

Referring first to Figs. 1, 2 and 4, in the heat-sealing apparatus chosen for illustration, there is a horizontal table comprising two portions 10 lying in the same plane, but spaced apart to form a central slot 11. Beneath each of the portions 10, there is a horizontally arranged pulley 12' mounted on the lower end of a vertical stub shaft 13, the latter being rotatably mounted at its upper end in one of the table portions lltl. Trained around each of the pulleys 12 is an endless belt 14, which extends lengthwise of the apparatus, and which is driven by suitable power means (not shown). At some distance from the pulleys i2; is a pair of heat- sealing rollers 15 and 16, which are tangentially arranged as may be seen clearly in Fig. 6. The roller 15 is heated, and has an attenuated edge, whereby it serves to seal the bag along a narrow line and at the same time to weaken the material so that the excess material of the bag beyond the sealing line may be readily detached and discarded.

ter the bags have been filled by hand, or by conventional apparatus, not shown, they are conveyed one at a time toward the sealing apparatus and introduced between the belts 14. The belts 14 engage the bag adjacent to the upper margin of its filled region (see Figs. 4 and 6) and advance the bag through the heat-sealing apparatus. An illustrative bag is shown at 19. When the bag 19 is delivered by the apparatus, it is in the condition shown in Fig. 7, wherein the bag mouth has been scaled along the line 20.

As has been mentioned, the merchandise contained in the bag does not completely fill the bag in its original non-sealed condition. This leaves the bag with an amount of unsupported excess material forming the bag mouth, and it is in the bag mouth region that the bag is sealed, preferably closely adjacent to the merchandise therein. However, since the bag material is extremely limp, and due to the fact that the region of the bag to be sealed is unsupported, producing a proper seal is very diflicult. The difficulty arises from the fact that when the excess material of the bag reaches the sealing rollers 15 and 16, the material tends to wrinkle thus preventing the formation of a proper seal.

In order to avoid this undesirable result, the invention contemplates the use of means arranged in advance of the sealing rollers for engaging the bag month before the latter reaches the sealing rollers, and holding the sides of the bag mouth in taut condition preparatory to its entering the bite of the sealing rollers. In this way, wrinkling of the bag material is prevented and a proper seal is assured.

Referring now to Figs. 1, 3 and 5, the means for maintaining the bag material in taut condition is shown, consisting of a pair of brushing instruments 211. Each of the brushing members 21 includes an elongated body portion 23 rotatably mounted adjacent its ends in a pair of brackets 26, which brackets are themselves fixed to one of the table portions 16). Projecting radially from the body 23 of each of the brushing instruments, are a number of brushing elements 27. In the present illustration, the elements 27 are shown as elongated paddles of yieldable material, such as, for example, soft rubber. Such paddles have the quality of good frictional engagement with the material of the bag, without causing damage to the bag material. Nevertheless, it should be mentioned that other materials such as for example, plastic or bristle, may be employed to form the brushing elements 27.

In the illustrated example, each of the brushing instruments 21 has four brushing elements 27. The body portion 23 preferably comprises a core 28, square in cross-section, and four channel members 29, one of which is fastened to each face of the core 28. The side members 36) of each of the channels 29 are arranged at complementary 45 angles to the base 31 of the members. Consequently, each side 3d assumes an opposed relationship to one of the sides 3% of an adjacent'channel member 29, thus forming a clamping means for gripping a brushing element along one of its longitudinal edges. The axes of the brushing members 21 are so spaced, that the tips of the brushing elements 27 carried thereby just meet along a line between these axes. As a result, when the brushing members are rotated in the direction of the arrows shown in Fig. 3, the brushing elements serve to sweep the bag mouth upward-1y and away from the body of the bag. The brushes therefore gather the excess material of the bag inwardly and upwardly until the material assumes a taut condition. Thereafter, continued rotation of the brushing instruments causes the brushing elements to maintain the bag mouth in this taut condition. In this condition, the bag reaches the sealing rollers 15 and 16, and as the bag mouth moves between the rollers there is no tendency to wrinkle.

The means for driving the brushing members 21 may be seen clearly in Figs. 1, 2 and 4. A plate 34 is keyed to each of the stub shafts 13, and is spaced above the pulley 12 associated therewith by means of a collar 35. The plate 34- thus rotates with the shaft 13 as the latter is driven by the belt 14. Below each of the table portions 10 is a shaft 36 mounted in the brackets 37 depending from the underside of the table portion. One end of the shaft 36 extends below the plate 34 and adjacent that end the shaft carries an elongated rotatable collar 38. The collar 38 is provided near one end with a rubber tire or rim 39 which frictionally engages the lower face of the plate 34. An endless belt 42 is trained about the collar 38 near its other end, and is also trained about the body portion 2 3 of one of the brushing members 21. It may be seen, therefore, that as the belts 14 are driven, each of the plates 34 is rotated and serves to drive the associated collar 38 by means of the frictional engagement with the rim 39. The collar 38 in turn drives the belts 42 which transmit the rotary motion to the associated brushing instrument 21. As long as the machine is running, therefore, and the belts 14 are operative to advance the bags through the machine, the brushing instruments 21 will be constantly rotated.

As will be seen in Fig. 1 each of the table portions 10 is provided with a slot 43, arranged directly above the rim 39, for accommodating a roller 44. Each roller 44 is rotatably mounted on a pin 45 fastened across the slot 43 and, as may be seen in Fig. 4, contacts the upper surface of the plate 34. The rollers 44 are supporting rollers, and each serves to balance the pressure of the rim 39 contacting the lower face of the plate.

Mounted on the upper face of each table portion 10 is a rigid plate or shield 46 (Figs. 1 and 3), which extends past the inner edge of the table portion 10 almost half-way across the slot 11. The height of the shield is such that the latter is disposed just out of the path of the rotating brushing elements 27. Due to the frictional engagement of the brushing elements with the bag material, these elements have a tendency to carry the bag mouth around with them and wind it on their associated brushing instrument 21. In order to avoid this undesirable result, the shields 46 are provided to strip the bag material from the brushing instruments as the latter rotate below them.

The invention has been shown and described in preferred form only and by way of example, but many variations and modifications may be made therein and in its mode of application which will still be comprised within its spirit. It is understood, therefore, that the invention is not limited to any specific embodiment except insofar as such limitations are specified in the appended claims.

What is claimed is:

1. In an apparatus for sealing the mouth of a plastic bag having two opposed side walls, a pair of sealing elements adapted to engage the two walls of the bag mouth between them, means for advancing the bag toward said sealing elements, and means for brushing the walls of the bag mouth away from the body of the bag just prior to the engagement thereof by said sealing elements, said brushing means comprising at least one rotary brushing instrument mounted on an axis parallel and adjacent to the path of movement of the bag toward said sealing elements, said brushing instrument being provided with brushing elements adapted to engage the bag mouth as the bag passes said instrument.

2. In an apparatus for sealing the mouth of a plastic bag having two opposed walls, the elements defined in claim 1 wherein said brushing elements are yieldable members projecting radially from said brushing instruments.

3. In an apparatus for sealing the mouth of a plastic bag having two opposed side walls, the elements defined in claim 1 wherein said advancing means comprises a pair of belts for engaging the body of the bag adjacent to the mouth and including means driven by one of said belts for rotating said brushing instrument.

4. In an apparatus for sealing the mouth of a plastic bag having two opposed side walls, the elements defined in claim 1 including a shield adjacent to said brushing instrument to prevent the bag mouth from winding around said instrument.

5. In an apparatus for sealing the mouth of a plastic bag having two opposed side walls, a pair of sealing elements adapted to engage the two walls of the bag mouth between them, means for advancing the bag toward said sealing elements, and means for brushing the walls of the bag mouth away from the body of the bag just prior to the engagement thereof by said sealing elements, said brushing means comprising a pair of rotary brushing instruments mounted on axes parallel and adjacent to the path of movement of the bag and on opposite sides of said path respectively, said instruments having brushing elements adapted to engage the bag mouth as the latter 5 passes between them.

References Cited in the file of this patent UNITED STATES PATENTS 1,993,442 Greven Mar. 5, 1935 10 2,287,957 Allen et a1 June 30, 1942 2,576,471 Messmer et al Nov. 27, 1951 2,890,554 Dolman et al June 16, 1959

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