US3113409A - Apparatus for exhausting air from packages made of tubular material - Google Patents

Description

Dec. 10, 1963 H. THURLINGS APPARATUS FOR EXHAUSTING AIR FROM PACKAGES MADE OF TUBULAR MATERIAL Filed Dec. 27, 1961 rm 7 55 9 m1 INVENTOF" HERMA NN TH U R L MM 8 a g W United States Patent 3,113,409 APPARATUS FOR EXHAUSTHN G AIR FROM PACK- AGES MADE 9F TUiiULAR MATERIAL Hermann Thiirlings, Viersen, Bezirk Dusseldorf, Germany, assignor to Hamac-Hansella Aktiengeselisehait,

a corporation of Germany Fiied Dec. 27, 1961, Ser. No. 162,474 Claims priority, application Germany Get. 14, 1961 3 Claims. (Cl. 53112) This invention relates generally to the art of packaging, and has particular reference to the production of packages composed of tubular material. The invention is directed to a method and apparatus for drawing off surplus air from the packages immediately prior to the time they are sealed.

In the production of packages of this kind, the general procedure involves the formation, in the packaging machine, of a tube of packaging material furnished in the form of a continuously-fed web.

The newly-formed tube is advanced step-wise in a longitudinal direction and transversely sealed by a pair of heated sealing jaws. A filling device is so arranged with respect to the tube that the product to be packaged is introduced into the successive bags as they are formed by the transverse sealing operation. The sealing jaws operate so that each transverse seal closes off the bag that has just been filled and defines the floor or lower seal of the next succeeding bag. After the jaws come together to produce the seal, they move downwardly so that a further length of the just-formed tubes of packaging material is drawn into filling position.

As a result of this procedure there is ordinarily sealed into each bag, in addition to the articles to be packed therein, a certain amount of air. This is a conspicuous and definite disadvantage, since large quantities of these packages are generally packed together in larger containers, such as cartons or the like, and as a result of the air in each package a large amount of packing space is lost in the larger container. Moreover, the individual packages that happen to be at the bottom of such a large carton are not always strong enough to withstand the continuous pressure upon them due to the weight of the packages above, as a result of which the locked-in air either gradually leaks out, so that the carton appears ultimately as though it had been insufficiently filled with packages, or the underlying packages may actually burst, especially in the region of the seams.

Although these disadvantages have existed for many years, no simple way has been found, until now, of withdrawing the surplus air from packages of the character described. Devices that have been suggested for this purpose are either too complicated or operate unsatisfactorily.

It has now been found that in a startlingly simple manner, the surplus air can be drawn oif. This can be achieved by blowing air into the tube of packaging material, just before the bag to be evacuated is sealed. The air blast is directed substantially opposite to the direction of advancement of the tube under the influence of the sealing jaws, i.e., the air is blown into the tube in the general direction in which the surplus air is to be withdrawn from the bag about to be sealed. This procedure may be carried out in an unusually simple manner, since very small volumes of air accomplish the desired purpose when they are injected in the form of pulses or bursts of air into the tube in the direction specified. It has been found particularly advantageous to introduce the air into the tube during the period when, in the normal course of closing the bag mouth, the cross-section of the tube at the mouth has already become somewhat narrowed.

Patented Dec. 1%, i963 ice A preferred embodiment of the apparatus is illustrated in the accompanying drawings in which:

FIG. 1 is a schematic representation of the essential parts of a packaging machine of the character described prior to the operation of the transverse sealing jaws to seal off the filled bag;

FIG. 2 is a view similar to FIG. 1 showing the jaws during the sealing operation;

FIG. 3 is an enlarged cross-sectional detail of the lower part of the filling device of FIG. 2; and

FIG. 4 is a view similar to the lower part of FIG. 2 showing the conventional sealing operation whereby a volume of surplus air is trapped in the bag that has been sealed.

By means of a forming shoe or guide 1 of known character, a continuously advancing web of packaging material 2 is formed into a tube 3 which is drawn downwardly over the tubular filling pipe 4. The filling pipe 4 is provided at the top with a hopper and feeding mechanism (not shown in detail) whereby predetermined charges are introduced into and through the filling tube, to the bag below it.

For the purpose of sealing the longitudinal seam of the tube 3, a longitudinal sealing iron or pressure pad 5 is provided. Transverse sealing of the tube to form individual bags is effected by a pair of transversely movable sealing jaws 6 which, in known fashion, move toward and away from each other. In addition, the jaws 6 are movable, longitudinally with respect to the tube. In practice, the jaws are separated during the upward movement to the position shown in FIGS. 1 and 2 at which point they move together to seal the bag. Then, while they remain together, they move downwardly and draw another length of the tube into position for the next filling operation. The pattern of movement of the jaws 6 is indicated by the arrows in FIG. 2.

The longitudinal sealing iron 5 is mounted on a piston 7, the head 8 of which is movable in a cylinder 9. Seated against one side of the piston 8 is a compression spring 16. On the other side of the piston the cylinder 9 is connected to an inlet conduit 11, leading from a three-way solenoid valve 12. From this valve a conduit 13 extends into the filling pipe 4 down to the bottom thereof. At that point, the conduit 13 is so formed (see FIG. 3) that it expels air in a direction generally opposite to the direction in which the sealing jaws move the tube 3, as indicated by the lines shown in FIG. 2. The valve 12 is also connected to an inlet pressure source 14.

The apparatus operates as follows:

By control of the valve 12 and the movements of the transverse jaws 6 in predetermined timed relation, pressure fluid from the inlet 14 is introduced through conduit 11 to the piston 8, to advance and thus operate the longitudinal sealing device 5, whenever the jaws 6 have been separated and are moving upwardly. The sealing iron 5 cooperates with the filling pipe 4 to seal the overlapping longitudinal margins of the material 2 and thus maintain it in tubular form. Shortly before the transverse jaws 6 contact each other to seal the just-filled bag, the valve 12 is actuated to close the connection between the pressure inlet 14 and the conduit 11. At the same time, the valve connects the conduit 11 to the conduit 13. As a result, the spring 10 is allowed to move the piston 8 leftwardly to the position shown in FIG. 2, whereby the longitudinal sealing iron 5 disengages the section of the tube 3 it has just sealed. The pressurized air in the conduit 11, as well as the small amount of air that was in the cylinder 9 before the piston 8 returned to the position of FIG. 2, pulses through the conduit 13 and is ejected from the outlet opening at the bottom thereof. This pulse or blast is in a direction opposite to that in which the packaging material travels. Consequently, the surplus air above the articles in the just-filled bag is sucked upward so that the walls of the bag come together snugly over the articles within the bag, as shown in FIG. 2.

It has been found effective to introduce this pressure blast or pulse after the sealing jaws 6 have already moved substantially toward each other, whereby only a relatively narrow, rapidly closing, opening exists between the bag Walls and hence between the filled bag and the space in the tube directly above the jaws 6.

During the closing movement of the jaws 6 toward each other, the longitudinal sealing device 5 remains in the lifted position shown in FIG. 2. After they engage each other, the jaws 6 move downwardly to draw a new length of the tube 3 into filling position. As soon as this movement of the jaws has been completed, the valve 12 is actuated in order to reestablish the connection between the pressure fluid from inlet 14 and the conduit 11 so that the longitudinal sealing element 5 is again moved forwardly to produce a longitudinal seam on a new length of the tube. The operation is then repeated.

The invention has been illustrated in a preferred form of packaging machine, in which the movements of the longitudinal seaming device 5 are pneumatically controlled, and in which the exhausting of the pneumatic device is employed for the purpose of producing the pressure blast in the filling pipe. The invention is, however, by no means restricted to pneumatically operable packaging machines or mechanisms. In machines which operate by other than pneumatic means, the pressure tube 13 can be connected to a small pump or the like which is operated in timed relation to the operation of the packaging machine, instead of to the three-way valve 12. In this way pressure blasts may be produced in pulses for the purpose of drawing off the surplus air from each bag as it is about to be sealed.

What is claimed is:

1. In a packaging machine having a filling pipe, a tube of packaging material disposed around the pipe, and a pair of transversely movbale sealing jaws beneath the filling pipe, the lower end of the tube being closed and depending from the lower end of the pipe to a point below the sealing jaws and said jaws being movable toward each other to seal the tube at a point above its lower end, means for drawing off the surplus air from the lower end of the tube comprising a pneumatic system for creating a discontinuous air blast, a conduit connected to said pneumatic system and extending into said filling pipe, the lower end of said conduit being so oriented that the air blast is introduced into said pipe in a direction away from the lower end of the tube, and a control valve associated with said pneumatic system for introducing said air blast into said pipe immediately prior to the engagement of the jaws to seal the tube.

2. In a packaging machine, the apparatus defined in claim 1 including a sealing iron operated by said pneumatic system for sealing the longitudinal seam of the tube of packaging material.

3. In a packaging machine, the apparatus defined in claim 2 wherein said pneumatic system comprises an inlet connection, a piston within a cylinder connected to said sealing iron by a piston rod, a spring urging said piston and hence said iron to an inoperative position, a second conduit extending from said cylinder, and a three-way valve between said inlet connection, first conduit and second conduit, said valve being said control valve and serving in one of its positions to connect said inlet and second conduit in order to move said iron to operative position, and serving in the other of its positions to connect said conduit to said first conduit whereby said spring is permitted to exhaust said system and produce the desired air blast.

Referenees (Iitetl in the file of this patent UNITED STATES PATENTS 2,160,367 MaXfield May 30, 1939 2,919,990 Podlesak et a1. Jan. 5, 1960 3,009,298 Gerlach ct a1. a NOV. 21, 1961 3,040,490 Virta June 26, 1962

Claims (1)

1. IN A PACKAGING MACHINE HAVING A FILLING PIPE, A TUBE OF PACKAGING MATERIAL DISPOSED AROUND THE PIPE, AND A PAIR OF TRANSVERSELY MOVABLE SEALING JAWS BENEATH THE FILLING PIPE, THE LOWER END OF THE TUBE BEING CLOSED AND DEPENDING FROM THE LOWER END OF THE PIPE TO A POINT BELOW THE SEALING JAWS AND SAID JAWS BEING MOVABLE TOWARD EACH OTHER TO SEAL THE TUBE AT A POINT ABOVE ITS LOWER END, MEANS FOR DRAWING OFF THE SURPLUS AIR FROM THE LOWER END OF THE TUBE COMPRISING A PNEUMATIC SYSTEM FOR CREATING A DISCONTINUOUS AIR BLAST, A CONDUIT CONNECTED TO SAID PNEUMATIC SYSTEM AND EXTENDING INTO SAID FILLING PIPE, THE LOWER END OF SAID CONDUIT BEING SO ORIENTED THAT THE AIR

Images