TAPE RESTRAINT FOR USE WITH WRAPPER SEALING ANVIL

Abstract: In a machine for making heat seals in plastic materials an anvil (14) having a cushioned surface (24) is overlaid with a nonstick tape (26) to preclude the plastic materials being sealed from sticking to the anvil (14). The nonstick tape (26) is wrapped around the anvil (14) such that it is restrained on the bottom side as well as the sides of the anvil.

Description: TAPE RESTRAINT FOR USE WITH WRAPPER SEALING ANVIL Background of the Invention This invention has to do with article wrapping machines of the type that forms a tube of film around articles being wrapped and at a subsequent station the tube is sealed and severed between the articles. More specifically this invention has to do with an improved sealing bar anvil that utilizes a nonstick tape on the anvil to preclude the sticking of molten film to the anvil. Summary of the Invention An anvil is provided having a base member which supports a cushion surface. The cushion surface is covered with a strip of nonstick material that is maintained in location by restraints that prevent the strip material edges from being loosened from engagement with the cushion surface. Brief Description of the Drawing Figures An understanding of this invention will be easily gleaned from a reading of this specification coupled with a perusal of the drawing figures wherein: Fig. 1 is a presentation of a sealing head mechanism showing the general environment of the invention; Fig. 2 is a cross sectional view of a portion of the invention; Fig. 3 is a cross sectional view of an assembled anvil showing the instant invention. Detailed Description of the Invention Fig. 1 shows the general environment of the invention, that being in a sealing head generally 10 having a seal bar 12 that will interact with a seal bar anvil 14 in a well known manner. The invention has to do with the construction, form and surface of the seal bar anvil 14. This anvil is rotated into contact with the seal bar 12 at a high production speed in order to seal a tube of film surrounding a product such as 16. The seal is a heat seal where the tube of film is captured between the seal bar 12 and the seal bar anvil 14. The short duration when the heated seal bar 12 is in contact with the anvil is adeguate to fuse the film together and thus provide a sealed end on the package. The quality of such a seal is very important particularly in the sealing of foodstuff packages. The seal must be continuous and strong. Ideally the seal will be "water tight" and will not fail before the adjacent unheated film. In production it has been found that the heat of the seal bar will cause the accumulation of melted film on the seal bar anvil. Such an accumulation is detrimental to forming good seals thus it has been found that by providing a nonstick surface on the anvil surface contacting the heated seal bar production runs of seals can be made without the accumulation of film debris on the anvil. One application of applying a nonstick surface to a seal bar anvil entails the use of nonstick tape (one side having an adhesive) on the anvil. Such tape application is well known in the art. Although such a tape application has proved advantageous ithas one fault. That is, the edges of the tape may loose contact with the host surface and thus provide an area where diterus may accumulate. When handling foodstuffs this may be unacceptable as cleaning tends to degrade the contact even more as high pressure water or steam may work its way under the tape. Figs. 2 and 3 provide a means of shielding any exposed edges of the nonstick tape from the effect of a high pressure stream of cleaning water from ripping the tape from the anvil. In Fig. 2 a frame 18 having a vertical component 20 and an attached horizontal component 22 provides a contact surface that the sealing bar will contact on each revolution of the sealing head 12. The 5 frame 18 is an elongated element that supports a cushion means 24 on the top surface of the elongated horizontal surface of the frame. The cushion is overlaid with a strip of nonstick tape 26 that is wrapped around the sides of the cushion and the sides of the horizontal 10 member of the frame. Fig. 3 shows how the frame is held in an anvil block 28. The anvil block is a generally elongated member having an elongated slot 30 formed therein to receive the frame 18 and specifically the vertical 15 component 20. A plurality of threading apertures are provided in the anvil block 28 to accommodate frame retainer means 32 which are in a preferred embodiment bolts. A second group or set of threaded apertures such as 34 are provided to accommodate fastening means 36, 20 herein restraint bolts, which will secure restraints 38 to the anvil block. The restraints, one on each side of the frame and anvil block assembly will protect the nonstick tape from the ends thereof being "pulled off" or otherwise degraded when the sealing head anvil is 25 being "power washed". A further advantage of this design is that the frame provides an easily replaceable element that can be quickly changed into the anvil block when a replacement is necessary. 30 Thus it can be seen that there has been provided a replaceable frame hosting a nonstick surface ) that can be easily installed into an anvil block on a sealing head of a sealing unit on a wrapper. Nuances of this design are contemplated by the inventor and minor 35 design changes are contemplated as being within the scope of the following claims.

Claims: What is claimed is: 1. In a sealing head for use in a wrapper, said sealing head incorporating a sealing bar and an anvil upon which said sealing bar will impact in sealing film surrounding articles to be wrapped, the improvement comprising: an anvil block having an elongated slot formed in a top surface thereof, said anvil block further having a plurality of threaded apertures formed in both side surfaces of said anvil block; a frame means having a vertical component connected to a horizontal component ring edges, said frame means being a generally elongated structure having a length similar to the length of said anvil block and said frame means vertical component carried in said elongated slot of said anvil block; a cushion means carried on the top surface of said horizontal component and extending the length of said horizontal component; a nonstick film covering the top surface of said cushion means and continuously extending adjacent said edges of said horizontal component of said frame means; restraint means carried by said anvil block and extending beyond said edges of said horizontal component said frame means to partially cover said nonstick film extending adjacent said edges of said horizontal component of said frame means. 2. The invention in accordance with Claim 1 wherein said restraint means is an elongated element carried on each side of said anvil block. 3. The invention in accordance with Claim 2 wherein said restraint means fastened to said anvil block. 4. The invention in accordance with Claim 3 wherein said frame means is restrained in said anvil block by means of a frame restraint fastener.

Inventors: LEINO LAWRENCE L, LEINO, LAWRENCE, L.
Applicants: FMC CORP, FMC CORPORATION
Application year: 1990
Main classification: B65B51
IPC codes: B29C65, B65B51, B65B65