EASILY REMOVABLE SELVAGE DEVICE
The problems associated with the prior art have been overcome by the present invention, which describes a device for spooling selvage as it is cut by a side-sealing machine. The device includes a two part core, which is held together by a friction fitting, such as a keyless bushing. The two parts of the core are shaped so that as the selvage is wound onto the core, it exerts both a radial and axial force on the core. This axial force provides the force needed to separate the two parts of the core when the bushing is removed. Various shaped core parts may be used, and various friction fittings are also envisioned.
Machines used to wrap and seal articles and packages in thermoplastic film are well known in the art. Two types of machines are commonly referred to as side-sealing and lap-sealing machines. In the typical side-sealing configuration, an article or set of articles travels, typically via a conveyer belt, toward the machine. A sheet of center-folded plastic film, having two layers, is fed from a direction, which is preferably perpendicular to the direction of the conveyer. The two layers of the film are then separated such that the article is placed between the lower layer and the upper layer. On one side of the article is the center-fold, while on the other side, there is an open edge where the two layers are not attached. The machine has several sets of belts to hold and guide the film, and a side sealing mechanism, which typically comprises a heating/sealing element that fuses or welds the two layers together and a cutting element that removes the excess material. In some embodiments, the heating element serves to cut the film as well. These elements, whether a unitary element or separate components, are referred to as the heating/sealing/cutting element throughout this disclosure. Thus, as the article passes by the side sealing mechanism, this open edge is sealed by welding the two layers together, the plastic is cut and the waste is removed. At this point, the plastic film resembles a tube, with openings at both the leading and trailing ends of the article, but sealed along both sides. As the article continues to advance, an end sealing mechanism is then employed to seal the film at the leading end of the article. The article is then advanced and the end sealing mechanism then seals the film at the trailing end of the article.
Typically, when the film is cut, the waste, or selvage, is pulled or transported away from the tube and discarded. In some embodiments, the selvage is wound onto a spool to keep the waste contained in a small, easily manageable area. When the spool is filled with selvage, the machine is stopped, the selvage is then removed from the spool and discarded.
As the waste is cut by the machine, it is at an elevated temperature. As it is wound on the spool, the selvage shrinks as it cools. In some cases, such as with specific types of film, the selvage shrinks and hardens to a point where it is difficult to remove from the spool. In these instances, typically the selvage must be cut off the spool. This is time consuming and reduces machine efficiency, as the machine is typically turned off while the selvage is being removed.
Therefore, it would be beneficial if there were a device which held the selvage as it was being removed by the machine, but allows the selvage to be easily removed without the use of a knife.
SUMMARY OF THE INVENTIONThe problems associated with the prior art have been overcome by the present invention, which describes a device for spooling selvage as it is cut by a side-sealing machine. The device includes a two part core, which is held together by a friction fitting, such as a keyless bushing. The two parts of the core are shaped so that as the selvage is wound onto the core, it exerts both a radial and axial force on the core. This axial force provides the force needed to separate the two parts of the core when the bushing is removed. Various shaped core parts may be used, and various friction fittings are also envisioned.
The side-sealing mechanism 20 is located on the open side 6 of the enveloped article. The mechanism holds the two layers of film 4,5 together, and guides the layers through the heating and cutting means. It then welds the two layers together, and cuts off the surplus material. The surplus material is pulled away so as not to reattach to the film while it is still at an elevated temperature.
As shown in
Each of the timing belts preferably has a special gripping outer surface, that is bonded to a truly endless steel or Kevlar reinforced timing belt. Each corresponding set of belts has upper and lower pressure plates that are preset to insure good contact between the pair of belts.
In one embodiment, as shown in
The side-sealing mechanism 20 includes the heating and cutting element 230. As described above, this element is preferably located between the upstream and downstream pulleys, so that it can seal and cut the film before it is separated by the downstream pulley. The heating and cutting element 230 may be any suitable shape and type. For example, the heating and cutting element 230 may be formed into an open oval, or may be a heated knife.
As the film is cut, the waste is removed and pulled away from the side-sealing mechanism. In some embodiments, the waste is routed through one or more loops 185 (see
In some embodiments, the spool rotates so as to wind the selvage onto the spool. The speed of rotation may be controlled in various ways. In one embodiment, the rotational speed of the spool is coupled to the speed that the film is moving on the mechanism 20. In another embodiment, the tension on the selvage as it approaches the spool is used to control the rotational speed of the spool. For example, if the tension is too low, the spool rotates more rapidly. If the tension is too high, the rotational speed of the spool slows. Of course, other methods of controlling the rotational speed of the spool, such as a slip clutch, can be used, without departing from the spirit of the invention.
When the selvage is spooled onto parts 301, 302, it may shrink as it cools. In certain embodiments, the selvage forms a hard plastic, which serves to tightly couple parts 301, 302 together. As the selvage cools, the majority of the compression force is directed radially on the parts, as the parts 301, 302 are relatively flat in the trough 310. This compression force served to bind the two parts 301, 302 together, often requiring an operator to pry the parts apart or cut the selvage off the spool.
To overcome this issue, the present device, shown in
Therefore, by utilizing two core parts 401, 402 which are shaped such that the compression force of the selvage creates an adequate axial force, the core parts 401, 402 are inherently being forced apart, thereby eliminating the issue of the core parts being affixed together by the selvage. In some embodiments, an incline angle greater than about 15° is used. In some embodiments, an incline angle of between about 15° and 20° is used, although other angles are also possible.
While two identical frustoconical parts 401, 402 may be used, the invention is not limited to this embodiment. For example, the two parts do not need to be symmetrical. For example, the incline angles of the two parts may differ. In other embodiments, the cones are not linear, but rather have a curvilinear shape.
In another embodiment, shown in
The use of core parts shaped so as to translate the compression force generated by the shrinkage of the selvage into an axial force greatly reduces the difficulty in separating the two core parts. In fact, in some embodiments, the axial force is sufficiently great that the two core parts separate as soon as the fastener used to hold them together is removed.
In some embodiments, the faster used to hold the two core parts together may be a threaded bolt, as is traditionally used in the prior art. However, in some embodiments, the axial force generated by the compression force is sufficiently high so as to cause the threaded bolt to seize, making it difficult to remove.
In some embodiments, a friction fitting is used to hold the core parts together on the rod. For example, a hydraulic keyless bushing, as shown in
Hydraulic fluid is contained within the flange 602. As the screw 603 on the flange 602 is tightened, the hydraulic fluid flows into the sleeve 601. This fluid causes the sleeve 601 to expand, both inwardly and outwardly. This inward expansion serves to tighten the sleeve 601 onto the rod, thereby forming a friction fitting.
In another embodiment, other types of keyless bushings are used. For example,
In fact, any fastener which uses radial force to fasten to the internal rod may be used. While hydraulic and wedge type keyless bushings are described, any such fastener may be used.
The core portions may be made of any suitable material, such as polyurethane, or a metal, such as aluminum. Thus, the invention includes at least one core portion which has an incline angle which translates the compression force of the selvage at least partially into a axial force, which in turn is used to separate the core portion from its adjacent component. In
The present disclosure is not to be limited in scope by the specific embodiments described herein. Indeed, other various embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Thus, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Further, although the present disclosure has been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes.
Claims
1. A side sealing machine for sealing a film, comprising:
- a cutting and heating element, having a leading edge adapted to encounter said film first, and to separate a portion of said film as selvage; and
- a spool for holding said selvage after it has been cut by said cutting and heating element; said spool comprising: a rod on which a core is placed, said core adapted to rotate to allow said selvage to accumulate on said spool; said core comprising at least one core portion, said core portion having an incline angle relative to a axis passing through said rod, said incline angle being sufficiently steep so as to translate a compression force caused by shrinking and cooling of said selvage into an axial force, said axial force sufficient to separate said core portion from an adjacent component located on said rod; and a fastener to hold said core onto said rod.
2. The side sealing machine of claim 1, wherein said core portion is frustoconical, having a narrower end and a wider end.
3. The side sealing machine of claim 2, wherein said adjacent component comprises a vertical wall adjacent to said narrower end of said frustoconical core portion.
4. The side sealing machine of claim 2, wherein said adjacent component comprises a second frustoconical core portion, having a narrower end and a wider end, arranged such that said narrower end of said frustoconical core portion is adjacent to said narrower end of said second frustoconical core portion.
5. The side sealing machine of claim 4, wherein said second frustoconical core portion is identical to said core portion.
6. The side sealing machine of claim 4, comprising two vertical walls, one adjacent to each wider end of a respective frustoconical core portion.
7. The side sealing machine of claim 1, wherein said fastener utilizes radial force to secure itself to said rod.
8. The side sealing machine of claim 7, wherein said fastener comprises a keyless bushing.
9. The side sealing of claim 8, wherein said fastener comprises a hydraulic keyless bushing.
10. The side sealing machine of claim 1, wherein said incline angle is greater than about 15°.
11. A side sealing machine for sealing a film, comprising:
- a cutting and heating element, having a leading edge adapted to encounter said film first, and to separate a portion of said film as selvage; and
- a spool for holding said selvage after it has been cut by said cutting and heating element; said spool comprising: a rod on which a core is placed, said core adapted to rotate to allow said selvage to accumulate on said spool; said core comprising a first core portion, said core portion having an incline angle relative to a axis passing through said rod, said incline angle being sufficiently steep so as to translate a compression force caused by shrinking and cooling of said selvage into an axial force, said axial force sufficient to separate said first core portion from an adjacent second core portion located on said rod; and a fastener to hold said core onto said rod.
12. The side sealing machine of claim 11, wherein said first and second core portions are frustoconical, each having a narrower end and a wider end, wherein said narrower ends are adjacent to one another.
13. The side sealing machine of claim 12, further comprising two vertical walls adjacent each wider end of said first and second core portions.
14. The side sealing machine of claim 11, wherein said fastener uses radial force to secure itself to said rod.
15. The side sealing machine of claim 14, wherein said fastener comprises a keyless bushing.
16. The side sealing machine of claim 11, wherein said incline angle is greater than about 15°.
17. A side sealing machine for sealing a film, comprising:
- a cutting and heating element, having a leading edge adapted to encounter said film first, and to separate a portion of said film as selvage; and
- a spool for holding said selvage after it has been cut by said cutting and heating element; said spool comprising: a rod on which a core is placed, said core adapted to rotate to allow said selvage to accumulate on said spool; said core comprising a first frustoconical core portion, said first core portion having a narrower end and a wider end, and a first incline angle relative to a axis passing through said rod, and an adjacent second frustoconical core portion having a narrower end and a wider end, and a second incline angle relative to a axis passing through said rod; wherein said narrower ends of said first and second core portions are adjacent to one another; said first and second incline angles being sufficiently steep so as to translate a compression force caused by shrinking and cooling of said selvage into an axial force, said axial force sufficient to separate said first core portion from said adjacent second frustoconical core portion; and a fastener to hold said core portions onto said rod.
18. The side sealing machine of claim 17, wherein said fastener uses radial force to secure itself to said rod.
19. The side sealing machine of claim 18, wherein said fastener comprises a keyless bushing.
20. The side sealing machine of claim 17, wherein said incline angle is greater than about 15°.
Type: Application
Filed: Mar 16, 2012
Publication Date: Sep 19, 2013
Inventors: Thomas Orsini (Leominster, MA), Daniel LaFrance (Worcester, MA)
Application Number: 13/422,047
International Classification: B65B 51/26 (20060101);