US3555780A

US3555780A - Sealing of cartons

Info

Publication number: US3555780A
Application number: US696073A
Authority: US
Inventors: John Anthony Rogers
Original assignee: Metal Box PLC
Current assignee: Crown Packaging UK Ltd
Priority date: 1968-01-05
Filing date: 1968-01-05
Publication date: 1971-01-19
Anticipated expiration: 1988-01-19

Abstract

OVERLYING CLOSURE PORTIONS OF A CARTON WHICH ARE TO BE SEALED BY HEAT-SEALABLE MATERIAL APPLIED THERETO ARE HELD IN SPACED ANGULAR RELATIONSHIP WHILE HIGH TEMPERATURE AIR IS APPLIED TO THE HEAT-SEALABLE MATERIAL TO EFFECT SOFTENING THEREOF, AFTER WHICH THE PORTIONS ARE PRESSED TOGETHER TO SEAL ONE TO THE OTHER.

Description

Jan. 19, 1971 ROGERS 3,555,780

SEALING OF CARTQNS Filed Jan. 5, 1968 United States Patent O U.S. Cl. 53375 7 Claims ABSTRACT OF THE DISCLOSURE Overlying closure portions of a carton which are to be sealed by heat-scalable material applied thereto are held in spaced angular relationship while high temperature air is applied to the heat-sealable material to effect softening thereof, after which the portions are pressed together to seal one to the other.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to the sealing of cartons and in particular to the sealing of cartons of the kind having underlying and overlying closure portions connected to opposite parts of the carton and secured one to the other by heat-sealable material applied to the engaging surfaces of said portions.

(2) Description of the prior art Some forms of cartons are made of cardboard or similar material coated with a heat-sealable material, such as polyethylene or a polyethylene/wax mixture and it has been proposed, following the insertion of the contents into the carton, to effect sealing by folding the overlying closure portions into engagement with the underlying closure portions to be engaged thereby and then moving the closed carton between heated elements which engage the exterior of the folded overlying portions. This proposal has the advantage that the folded overlying closure portion can be readily heated over its whole surface so that a seal can be obtained along the edges thereof, the machine is relatively compact because all seals are effected simultaneously and the sealing can be effected in a vertical plane requiring little floor space, and the closing action, which is effected as the cartons are moved be tween the heated elements tends to draw the lid of the carton lightly down against the body of the carton. The proposal does, however, have the disadvantages of heating by conduction through the carton material which is inefficient and accordingly slow, and the external surfaces of the overlying closure portions must be raised to a high temperature which may lead to damage to the printing or other surface decoration applied to the overlying closure portions.

According to another proposal the heat-scalable material applied to overlying and underlying closure portions of a carton is heated by high temperature air while the carton is being moved along a predetermined path and the overlying closure portions are held in positions substantially at right angles to the underlying closure portions to be engaged thereby and after the heat treatment the overlying closure portions are folded and pressed into engagement with each other. This proposal has the advantage of a short heating time, using a heater which is simple and has a long life, and the heat-scalable material is heated directly so that the exterior decorated surface of an overlying closure portion is virtually unheated. However, this proposal has the disadvantage of requiring that the whole of each overlying closure portion be heated if sealing is required along all of the edges thereof and if there are overlying closure portions on each of three sides of a four-sided carton the machine becomes bulky, that is it requires relatively considerable floor space, because it is necessary to perform the heating and folding of two opposite overlying closure portions while moving the carton in one path and then to heat and fold the third overlying closure portion after turning the carton through and effecting heating and folding thereof while moving the carton in a second path.

It is an object of the present invention to provide apparatus for closing and sealing cartons which avoids the disadvantage of the said prior proposals while retaining the advantages of both.

SUMMARY According to the invention there is provided apparatus for closing and sealing a carton having underlying and overlying closure portions connected to opposite parts of the carton and secured one to the other b heat-scalable material applied to the engaging surfaces of said portions comprising intermittently operable support means movable between positions of rest of the carton at one of which an underlying closure portion is substantially at right angles to the carton portion to which it is connected and at which means engage the overlying closure portion to support it in spaced angular relation with the underlying closure portion, air delivery means operable while the carton is in said one position thereof to direct high temperature air on to those areas of the angularly spaced overlying and underlying closure portions which are to be sealed one to the other, and means located at a subsequent rest position of the carton carried by the support and operable to effect sealing relation between the heat treated underlying and overlying closure portions.

In one embodiment of the invention the carton is moved on to the support by a conveyor, the support is movable to and from said one position thereof in a direction at right angles to the direction of movement of the conveyor towards the support, and an overlying closure portion folding and pressure-applying device is located in the path of the support and is arranged to fold and press the heattreated overlying closure portion against the underlying closure portion on movement of the carton by the support into operative relation with said device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one kind of carton which can be closed and sealed in accordance with the invention, and

FIG. 2 is a diagrammatic perspective view of apparatus according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 of the drawings, the carton illustrated in FIG. 1 comprises a body consisting of a bottom 1, side walls 2, 3, a front wall 4, a rear wall 5, a lid 6 hingedly connected to the top of rear wall 5, and side flaps 7, 8 and a front flap 9 hingedly connected to the lid 6, which respectively are to overlie and be secured to the underlying closure portions constituted by the side walls 2, 3 and front wall 4. The surfaces of the underlying closure portions 2, 3, 4 and of the overlying closure portions 7, 8, 9 are coated with a heat-scalable material, not shown, such as polyethylene or a polyethylene/wax mixture.

The apparatus, FIG. 2, comprises a conveyor, shown as a reciprocable pusher 10, which is operable to move a carton on to a support 11 intermittently movable to and from one position thereof to support the carton in a position of rest, this being the position shown in FIG. 2, the support 11 is movable to and from said one position thereof in a direction at right angles to the direction of movement of the pusher towards the support 11. The pusher 10 may be operated in any desired manner, for example by an air cylinder 12. Folder elements 13 are engageable with the overlying closure portions 7, 8, and folder elements not shown with the overlying closure portion 9, to cause them to be folded outwards. As shown, the arrangement is such that the overlying closure portions form acute angles with the underlying closure portions 2, 3, 4 which, as shown in FIG. 1, are substantially at right angles to the carton portions to which they are connected. This angular relation between the overlying and underlying closure portions is retained while the carton is on the support 11 and the support is in said one position thereof at which the carton is in a position of rest. Air delivery means is arranged while the carton is at rest on the support 11 to direct high temperature air, that is air at a temperature of the order of 500 C., on to those areas of the overlying and underlying closure portions which are to be sealed one to the other. Means are located at a subsequent position of rest of the carton carried by the support 11 and are arranged to effect sealing relation between the heat treated overlying closure portions.

As shown in FIG. 2, the air delivery means comprises for each pair 2, 7; 3, 8; 4, 9 of overlying and underlying closure portions a tube 14 of right-angled triangular crosssection and the through passages of the tubes 14, which are preferably formed in continuation one with the other, are connected with a source of high temperature air, not shown, which may be similar to that described in British patent specification No. 1,071,040 or No. 1,071,276. The sides of the tubes 14 are provided with perforations 15 through which air passes continuously and is directed on to the engageable surfaces of the pairs of overlying and underlying closure portions and is applied thereto for an interval of time, about A to /2 second, sufficient to soften the heat-sealable material for sealing. The tubes 14 stand on the bases of the triangular section thereof and the overlying and underlying closure portions of each pair thereof respectively each overlie one side of the tube 14 appropriate thereto. The perforations 15 are so arranged as to define on the overlying and underlying closure portions predetermined areas to be softened for sealing one to the other. As shown in FIG. 2, the perforations 15 are arranged to define a U-shaped sealing band, about inch in width, one edge of which coincides with the edges of overlying or underlying closure portions as appropriate. It will be understood, however, that the arrangement of the perforations 15 may be such as to provide any desired pattern of sealing area, for example curved or triangular, to acccommodate overlying closure portions of any shape. Further, if desired, the perforations may provide for sealing areas having breaks therein to facilitate opening of the carton after sealing thereof. Suitable spacing means, for example locating pins which extend from the perforated sides of the tubes 14, are provided to space the overlying and underlying closure portions from the perforated walls of the tube. The spacing may be of the order of A to inch.

The device which folds the overlying closure portions and applies pressure thereto comprises a chamber 16 having a through passage 17 in which a carton is located at rest until the next succeeding carton is moved in to the chamber by the support 11 and the entrance to the passage 17 is formed so as to fold the overlying portions 7, 8, 9 into engagement with the underlying portions 2, 3, 4 as the carton enters the passage. The sides of the chamber are a tight fit about the carton so as to press the engaged overlying and underlying closure portions against each other to effect sealing thereof one to the other. The sides of the chamber may be formed by hollow walls through which a cooling medium, for example water, may be caused to flow.

As one carton is moved into the chamber 16 the carton already in the chamber is ejected thereby and may be removed by any suitable means. Alternatively, if desired, the chamber may communicate with a stacker which receives the cartons passing out of the chamber.

The support 11 co-operates with a table 18 from which a carton is moved by the pusher 10 on to the support 11 and the cartons are fed over the table 18 into the path of the pusher 10 in a direction at right angles to the direction in which they are moved by the pusher 10 on "to the support by a second reciprocable pusher 19. As shown in FIG. 2 the cartons are first moved over the table 18 in a feed-in path which is defined by guides 20 and which is parallel to the path in which the cartons are moved by the pusher 10. The cartons are delivered to the feed-in path in any desired manner, not shown from a cartonfilling machine and as each carton engages a detector switch 21 the switch initiates operation of the second pusher 19. A wing 22 on the second pusher 19 arrests the next succeeding carton until the pusher 19 is returned to the starting position thereof. The pusher 19 pushes the carton against a second detector switch 23 which initiates operation of the first pusher member 10. The lid 6 of the carton is folded down either manually or automatically so that the folder elements 13 can "effect downfolding of the overlying closure portions 7, 8 and the overlying closure portion 9 is downfolded by a shaped member, not shown, attached to the bottom of the chamber 16.

I claim:

1. Apparatus for closing and sealing a carton of the kind having underlying and overlying closure portions connected to opposed wall panels of the carton and secured one to the other by heat-sealable material applied to the engaging surfaces of said portions, comprising intermittently operable support means movable between positions of rest of the carton at one of which an underlying closure portion is substantially at right angles to the carton wall panel to which it is connected, folder means operable to engage the overlying closure portion and to move it into predetermined spaced angular relation with the underlying closure portion to form an acute angle therewith, high temperature air delivery means operable while the carton is in said one position thereof and comprising a tube including two substantially plane walls forming one with the other an angle corresponding to said acute angle so that said Walls are substantially parallel with and in close proximity with said underlying and overlying closure positions, said walls each being provided with perforations through which high temperature air is directed on to those areas of the angularly spaced overlying and underlying closure portions which are to be sealed on to the other, and means located at a subsequent rest position of the carton carried by the support and operable to effect sealing relative between the heat treated underlying and overlying closure portions, said carton being moved onto the support means by a conveyor, the support means is movable to and from said one position of rest of the carton in a direction at right angles to the direction of movement of the conveyor towards the support means, and an overlying closure portion holding and pressureapplying device is located in the path of the support and is arranged to fold and press the heat treated overlying closure portion against the underlying closure portion on movement of the carton by the support means to the subsequent rest position of the carton.

2. Apparatus according to claim 1, wherein said tube is of triangular cross-section and has closed ends.

3. Apparatus according to claim 2, wherein the perforations are so arranged as to define on the overlying and underlying closure portions predetermined areas to be softened for sealing one to other.

4. Apparatus according to claim 1, wherein said folding and pressure-applying device is a chamber having a through passage in which a carton is located until the next succeeding carton is moved into the chamber by the support means, the entrance to the passage being so formed as to fold the overlying closure portions into engagement with the underlying closure portions as the carton enters the chamber and the sides of the chamber being a tight fit about the carton to press the engaged overlying and underlying closure portions against each other to effect sealing thereof one to the other.

5. Apparatus according to claim 3, wherein said folding and pressure-applying device is a chamber having a through passage in which a carton is located until the next succeeding carton is moved into the chamber by the support means, the entrance to the passage being so formed as to fold the overlying closure portions into engagement with the underlying closure portions as the carton enters the chamber and the sides of the chamber being a tight fit about the carton to press the engaged overlying and underlying closure portions against each other to effect sealing thereof one to the other.

6. Apparatus for closing and sealing a carton of the kind having underlying and overlying closure portions connected to opposed wall panels of the carton and secured one to the other by heat-scalable material applied to the engaging surfaces of said portions, comprising intermittently operable support means movable between positions of rest of the carton at one of which an underlying closure portion is substantially at right angles to the carton wall panel to which it is connected, folder means operable to engage the overlying closure portion and to move it into predetermined spaced angular relation with the underlying closure portion to form an acute angle therewith, high temperature air delivery means operable while the carton is in said one position thereof and comprising a tube including two substantially plane walls forming one with the other an angle corresponding to said acute angle so that said walls are substantially parallel with and in close proximity with said underlying and overlying closure portions, said Walls each being provided with perforations through which high temperature air is directed on to those areas of the angularly spaced overlying and underlying closure portions which are to be sealed on to the other, and means located at a subsequent rest position of the carton carried by the support means and operable to eifect sealing relation between the heat treated underlying and overlying closure portions, the movable support means cooperating witha table from which a carton is moved by the conveyor on to the support means, wherein the conveyor is a reciprocable pusher, and wherein cartons are fed over the table into the path of the pusher in a direction at right angles to the direction in which they are moved by the pusher on to the support means.

7. Apparatus according to claim 6, wherein the cartons are first moved over the table in a feed-in path parallel to that in which they are moved on to the support means by said pusher and wherein a second reciprocable pusher is operable to move the cartons in succession from the feed-in path into the path of the pusher which moves them on to the support means.

References Cited UNITED STATES PATENTS 3,020,691 2/1962 Oxborrow 53388X 3,309,841 3/1967 Egleston et al. 53375X 3,340,777 9/1967 Hittenberger et al. 53-375X 3,389,645 6/1968 Winters et a1 53-375X TRAVIS S. MCGEHEE, Primary Examiner US. Cl. X.R. 53-388