Patent Publication Number: US-6209174-B1

Title: One-piece molded strap

Description:
FIELD OF THE INVENTION 
     The present invention relates to devices used to secure a printing plate to a high speed roller machine. 
     BACKGROUND OF THE INVENTION 
     High speed roller machines are used to imprint a desired pattern on a variety of commercial articles. Typically, a printing plate having a desired pattern to be imprinted upon the article is attached to a drum of the high speed roller machine. Conventional high speed roller machines have used a multiple-piece strap to secure the printing plate to the drum. Such conventional multiple-piece straps consist of a rigid latch member connected to a rigid body member by a preformed elastomeric interconnect member. The rigid latch member and the rigid body member are each secured to the elastomeric member by an adhesive material. Such conventional multiple-piece straps have several drawbacks. By way of example only, exposure of such conventional multiple-piece straps to high rotational speeds over a short period of time causes the adhesive to degrade which results in the rigid latch members and/or the rigid body member becoming disengaged from the elastomeric interconnect member and ultimately the failure of the strap to secure the printing plates to the drum of the high speed roller machine. 
     The principal object of the present invention is to develop a strap for securing printing plates to a high speed roller machine which is significantly stronger and more durable then conventional straps thereby increasing the life of the strap and a process for manufacturing the same. 
     Another object of the present invention is to develop a strap for securing printing plates to a high speed roller machine which is less expensive to produce then conventional straps and a process for manufacturing the same. 
     SUMMARY OF THE INVENTION 
     The present invention is a one-piece molded strap used to secure a printing plate to a drum of a high speed roller machine. The one-piece molded strap comprises a rigid latch portion, a rigid elongated body portion and an elastomeric portion. The rigid latch portion is integrally formed with and chemically bonded to one end of the elastomeric portion. The rigid elongated body portion is integrally formed with and chemically bonded to the other end of the elastomeric portion. The one-piece molded strap is formed by an injection molding process whereby the material composition of the rigid latch portion and the rigid elongated body portion are compatible with the material composition of the elastomeric portion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following description of the invention will be better understood with reference to the accompanying drawings in which: 
     FIG. 1 is a bottom plan view of the one-piece strap of the present invention; 
     FIG. 2 is a side view of the one-piece strap of the present invention; 
     FIG. 3 is a section view taken along line  3 — 3  of FIG. 1; 
     FIG. 4 is a section view taken along line  4 — 4  of FIG. 1; and 
     FIG. 5 is a flow chart showing one embodiment of a process for forming the one piece strap of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is a one-piece strap for quickly securing one or more printing plates to a drum or cylinder of a high speed roller machine. Referring to FIGS. 1-4, wherein a first embodiment of the one-piece molded strap  10  of the present invention is shown generally comprising a latch or grip member  12  connected to an elongated body member  14  by an elastic interconnect member  16 . 
     The latch member  12  generally comprises a substantially planar median portion  18 , a substantially planar first end portion  20  which is engaged with the interconnect member  16  (to be described) and a second end portion  22  which is secured to the drum and/or cylinder of a high speed roller machine (not shown). The second end portion  22  is bent upward to form a clip or gripping area  24  which is secured to the drum by a variety of means including slots and/or flanges (not shown) provided in the drum. The latch member  12  is preferably made from a rigid and high strength material such as nylon or polyproplyene and is preferably manufactured by an injection molding process. 
     The elongated member  14  may take a variety of different lengths depending upon the size of the roller and generally comprises a substantially planar median portion  26 , a substantially planar end portion  27  and a substantially planar end portion  28 . The end portion  28  is securely engaged with the interconnect member  16  (to be described) and the end portion  27  is secured to the roller by a variety of means including being folded within slots (not shown) provided in the roller. The elongated member  14  is preferably made from a rigid and high strength material such as nylon or polypropelene and is manufactured by an injection molding process. 
     The interconnect member  16  generally comprises a median portion  30  and first and second end portions  32  and  34 . The first end portion  32  is securely engaged with the second end portion  20  of the latch member  12 . The second end portion  34  is securely engaged with the end portion  28  of the elongated member  14 . The interconnect member  16  is preferably made from a highly elastic material containing a chemical bonding agent such as thermo plastic rubber (TPR) or TPO. The elasticity of the interconnect member  16  allows the latch member  12  and the elongated member  14  to be pulled apart or stretched as desired and to securely hold the printing plate upon the drum under tension and during high speed printing operations. The material composition of the interconnect member  16  is compatible with the material composition of the latch member  12  and the elongated body member  14 . The interconnect member  16  is preferably molded with and about the second end portion  20  of the latch member  12  and the end portion  28  of the elongated member  14  and chemically bonded thereto to form a one-piece molded structure. The one-piece molded strap  10  is significantly stronger and more durable than conventional multiple-piece straps. Unlike conventional multiple-piece straps, the latch member  12  and/or the elongated member  14  will not become disengaged from the interconnect member  16  when exposed to high rotational speeds thereby providing secure and reliable engagement of the printing plates to the drum of the high speed roller machine. 
     Referring to FIG. 5, wherein a process for manufacturing the one-piece molded strap  10  of the present invention is described. As shown by block  50 , the process comprises the step of opening a hollow cavity mold. As shown by block  52 , the process comprises the step of placing said first end of said rigid latch portion and said first end of said rigid elongated body portion into the hollow cavity mold. As shown by block  54 , the process comprises the step of closing the hollow cavity mold. As shown by block  56 , the process comprises the step of injecting a thermoplastic material into the hollow cavity mold under heat and pressure. The thermoplastic material has a material composition which is compatible with the material composition of the rigid latch portion and the rigid elongated body portion. As shown by block  58 , the process comprises the step of cooling the hollow cavity mold. As shown by block  60 , the process comprises the step of opening the hollow cavity mold. As shown by block  62 , the process comprises the step of removing the resulting one-piece strap from the hollow cavity mold. 
     The foregoing description is intended primarily for purposes of illustration. This invention may be embodied in other forms or carried out in other ways without departing from the spirit or scope of the invention. Modifications and variations still falling within the spirit or the scope of the invention will be readily apparent to those of skill in the art.