APPARATUS AND METHOD FOR SEALING CONTAINERS HAVING TRIANGULAR PIPE Technical Field The present invention relates to an apparatus for sealing and folding a fin of a container having a triangular top. Specifically, the invention relates to a sealing configuration on the face of one or more sealing jaws that seals the fin and further forms a fold at the base of the fin that helps maintain the integrity of the fin shape and seal. .
BACKGROUND OF THE INVENTION Folding cartons or boxes having triangular finials have been known in most of the twentieth century. Its simplicity and re-sealing capabilities have helped to maintain its popularity as carton packs for traditional liquid food products such as milk and juice, but in recent years they have been used for products ranging from ammunition to Epsom salts. The cartons having a triangular top start as blanks of the carton in general rectangular made with folds to facilitate bending and the formation of the blank to a carton. During decades of development, manufacturers of packaging or packaging machines have devised a variety of ways to form, fill and seal cartons that have a triangular top. At present, the most prevalent packaging machines for filling and sealing the REF: 24116 cartons having triangular top are adapted to receive the cardboard blank after it has been sealed from the sides. The process of sealing the sides involves sealing the opposite vertical edges of the cardboard blank together to form a polygonal (usually rectangular) sheath. The casing or sheath is received on an adjustable mandrel which rotates the casing to the respective positions wherein the end of the casing extending outwardly from the mandrel is bent and sealed to form the bottom or bottom of the carton . After the bottom or bottom of the carton has been formed, it is removed from the mandrel and transported to a filling station where the carton is filled with product. Once the carton has been filled, the top of the carton is folded to the familiar triangular top configuration and thermally sealed to complete the packaging or packaging process. An example of a known packaging machine which generally operates in accordance with these principles is described in U.S. Patent No. 3,789,746 issued to Martensson et al. Other examples of such packaging or packaging machines are described in U.S. Patent No. 3,820,303 issued to Martensson et al., U.S. Patent No. 4,759,171 issued to Bruveris et al. and U.S. Patent No. 4,790,123 issued to Ljungstrom et al. These patents are hereby incorporated by reference.
Several mechanisms are known to seal the fin at the triangular end of the carton pack having a triangular top. One such mechanism is described in U.S. Patent No. 3,200,557 issued to Schwenk. In accordance with the teachings of that patent, the top flap panels forming the triangular trussed structure, including the flap, are sealed first to allow the polyethylene coating on the cartons to soften. Then the carton is transported to a position between two senate jaws. The sealing jaws move towards each other and apply pressure to form and seal the fin. The fins that are sealed in accordance with the teachings of the prior patents have a tendency to separate in the region below the main horizontal seal. Additionally, the thermal sealing process of the fin of the container having a triangular finish can take a long time and limits the performance of the packaging machine. Accordingly, an improved sealing apparatus is desirable.
SUMMARY OF THE INVENTION A sealing device is described which helps to overcome the above problems. The sealing device includes a first sealing jaw for sealing a fin of the container having a triangular top. A second sealing jaw is disposed opposite the first sealing jaw.
The first and second sealing jaws include a surface or generally flat face portion. The second sealing jaw further includes a sealing bar extending from a mid region of its face or surface portion generally flat longitudinally along at least a portion thereof to seal the fin of the container having a triangular top with , for example, ultrasonic energy. A shoulder extends respectively from each of the generally flat face or surface portions in a position to form a fin base fold at the base of the fin, for example, over the weak fold existing at the base of the fin. . The fold of the base of the fin helps to prevent separation at the base of the fin under the main horizontal seal formed by the sealing bar. The sealing bar may extend from the generally flat face portion of the second jaw to a distance beyond the degree to which the shoulders extend from their respective face portions. The shoulders can thus exert less pressure on the fin than the sealing bar. According to a further embodiment of the sealing jaws, the sealing bar is replaced by a plurality of generally circular sealing extensions. By using a plurality of generally circular sealing extensions, it becomes possible to better regulate the amount of ultrasonic energy transmitted to the fin, thereby providing the ability to make the thermal sealing process more efficient in time and energy. According to a further embodiment of the sealing jaws, the degree to which the circular protrusions and extensions protrude from the generally flat face portions is reduced in the vicinity of the opening end of the fin. This facilitates the opening of the container having a triangular top, while ensuring the sealing of the appropriate flap. One method of using the sealing jaws and a triangular sealed cap configuration with the sealing jaws is also contemplated. Other advantages of the present invention will become apparent with reference to the detailed description enclosed in conjunction with the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a first jaw. Figure 2 is a perspective view of a second jaw. Figure 3 is a side view of the first and second jaws in an open condition with a flap disposed therebetween. Figure 4 is a side view showing the jaws of Figure 3 in the closed position that contact the fin of a container having a triangular top. Figure 5 is a side view of a further embodiment of the first and second jaws. Figures 6 and 7 illustrate a flap that has been sealed using the described sealing jaws. Figure 8 is a top plan view of the second jaw showing the sealing extensions.
Figure 9 is a top plan view of the first jaw showing the shoulder extension. Figure 10 is a perspective view of an alternative embodiment of the first and second jaws.
Detailed description of the preferred embodiment Figures 1 and 2 illustrate a first jaw 20 and second jaw 25 respectively. The first and second jaws 20, 25 can be used in an ultrasonic sealing mechanism such as that described in the US patent application Serial No. 08 / 315,412 (Proxy Registration No. 10454US01; TRX Company Registration No.) -0082), entitled "Ultrasonic Carton Sealer", presented on the same date with the present and which is hereby incorporated by reference. As illustrated, the first jaw 20 includes a generally flat face portion 30. A shoulder 35 extends outwardly from the generally flat face portion 30 in a lower region thereof. The second jaw 25 also includes a portion 40 of generally flat face. A shoulder 35 extends outwardly from the generally flat face portion 40 in a lower region thereof. A plurality of generally circular sealing extensions 45 extend outwardly from the generally flat face portion 40 in a region disposed above the shoulder 35. The degree to which the sealing extensions 45 extend from the face portion 40 is greater. that the degree to which the shoulders 35 extend from their respective face portions 30 and 40. Figures 3 and 4 illustrate the relative position of the first jaw 20 and the second jaw 25 in an open condition with a vane 50 of a container having a triangular top disposed therebetween. As illustrated, the generally circular sealing extensions 45 are arranged close to a middle region of the fin, while the shoulders 35, illustrated herein with a generally curved cross section, reach a vertex that is disposed near the base. of the fin 50. The juxtaposed jaws 20 and 25 are movable towards each other in the directions illustrated by the arrows 55 and away from each other in the direction illustrated by the arrows 60. Figure 4 illustrates the jaws 20 and 25 in a closed state. In the closed state, the jaw 25 which may be for example an ultrasonic horn, transmits ultrasonic energy to the fin 50 for a predetermined period of time, which causes the polyolefin barrier layers of the contact surfaces 60 and 70 of the fin juxtaposed are softened, in such a way that the surfaces can be joined together in the area of extensions 45 in general circular. The use of the plurality of generally circular sealing extensions, as opposed to a single shoulder, facilitates a high degree of control over the amount of ultrasonic energy used to seal the fin 50. Such control further reduces the amount of time required to cool the flap 50 after the predetermined period of time in which the ultrasonic energy is applied.
At the same time that a seal is formed by the circular extensions 45, the shoulders 35 come into contact with the base of the fin to form a crease of the base of the corrugated fin, for example over the weak folds existing in the base of the flange. the fin. Due to the difference in the degree to which the shoulders 35 and the sealing extensions 45 extend, the pressure applied by the shoulders 35 to form the crease of the base of the corrugated fin is less than the pressure applied by the circular extension 45. As such, the amount of ultrasonic energy transmitted to the fin 50 in the base region is less than the amount of ultrasonic energy transmitted to the fin in the sealing region. Figure 5 illustrates a further embodiment of the first and second jaws 20 and 25. In this embodiment, the shoulders 35 have a trapezoidal cross section which for example, can provide a more defined fold than the shoulders 35 illustrated in Figures 3 and 4. As in the previous mode, the projections do not extend to the same degree as the sealing extensions. Figures 6 and 7 illustrate the triangular finishing end 80 of a container 85, wherein the fin 50 has been sealed with the first and second described jaws 20 and 25. As illustrated, the fin 50 extends longitudinally from an open end 90 to a closed end 95. A plurality of circular sealing regions 100 are arranged longitudinally along the middle portion of the fin to form the primary seal. The base fold 105 of the fin extends longitudinally along the base of the fin 50. A uniform seal along the length of the fin may not be desirable where, for example, the triangular fin has an open end and a closed end. Rather, it may be desirable to provide a seal that opens more easily at the open end 90 than the closed end 95. Figures 8 and 9 illustrate the modifications to the circular extensions 45 and the shoulders 35 to accomplish this objective. As illustrated, generally circular extensions taper to a decreased degree of extension in region 110 while ridges 35 also taper to a decreased degree of extension in region 115. Regions 110 and 115 are disposed near the end. open 90 of the flap when the first and second jaws 20 and 25 close to seal and fold the flap 50. Thus less ultrasonic energy will be applied in the regions 110 and 115 to thereby provide a seal at the open end 90 that is broken more easily than the seal at the closed end 95. An alternative embodiment of the first and second jaws 120 and 130 is illustrated in FIG. 10. The first and second jaws 120 and 130 include a generally flat face portion 125 and 135 respectively . A shoulder 104 extends outward from the generally flat face portion 125 and 135. Instead of the plurality of circular seal extensions, the second jaw 130 has a solid bar 145 extending outward from the face portion 135 generally flat in a region disposed above the shoulder 140. To achieve the same purpose of providing a seal that opens more easily at the open end 90 than the closed end 95 of the triangular top, the solid bar 145 and the shoulders are tapered to a decreased degree of extension in regions 150 and 155. Although the present invention has been described with reference to specific embodiments, those skilled in the art will recognize that changes can be made thereto without departing from the scope and spirit of the invention as it is summarized in the appended claims.
It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention is the conventional one for the manufacture of the objects to which it refers.
Having described the invention as above, property is claimed as contained in the following