Paper wrapped foam cup and method of assembly
A commercially viable paper wrapped foam cup comprising a taper portion that prevents the shrinkage-induced curling from interfering with the un-nesting of nested paper wrapped foam cups. The paper wrapped cup further comprises a fillet for strengthening the cup foot to retard shrinkage-induced curling of the foot. The paper wrapper has abutting to overlapping opposing ends to completely hide the foam cup to enhance the visual appearance of the cup. The overlapping portions of the paper wrapper are not bonded to each other to prevent wrinkling of the paper wrapper as the cup shrinks. A machine and corresponding method provide for automatically supplying foam cups and paper wrappers, wrapping the paper wrapped cup, and stacking the wrapped cups.
1. A method for automatically assembling a wrapper to an outer surface of a pre-made foam cup to form a wrapped foam cup, the method comprising:
1) automatically supplying a pre-made expanded foam cup on a rotatable mandrel having an axis of rotation and freely rotatable about the axis of rotation;
2) automatically supplying a wrapper sized to be wrapped about an exterior of the foam cup on a rotatable platen having an axis of rotation;
3) heating the wrapper to a temperature where the wrapper will bond to the exterior of the foam cup;
4) automatically wrapping the wrapper about the exterior of the foam cup by rotating the platen about its axis of rotation into contact with the foam cup to effect the free rotation of the mandrel about its axis of rotation to roll the foam cup over the surface of the platen to wrap the wrapper on the platen about the exterior of the foam cup;
5) repeating steps 1-4 multiple times to form multiple wrapped cups; and
6) automatically assembling at least some of the multiple wrapped cups into a group suitable for subsequent handling.
2. The method of claim 1 , wherein the wrapping step further comprises pressing together the wrapper and the cup while the wrapper is being wrapped onto the cup.
3. The method of claim 2 , wherein the heating step further comprises heating the wrapper prior to the wrapping step.
4. The method of claim 3 , wherein the heating step further comprises heating the wrapper during the wrapping step.
5. The method of claim 3 , wherein the heating step further comprises heating the wrapper to a temperature within the range of 375° F. to 440° F.
6. The method of claim 5 , wherein the heating step further comprises heating the wrapper to a temperature of less than 400° F.
7. The method of claim 5 , wherein the wrapping step is completed within 3 seconds.
8. The method of claim 7 , wherein the wrapping step is completed within 2 seconds.
9. The method of claim 7 , wherein the assembling step comprises accumulating a predetermined number of wrapped cups and then packaging the predetermined number of wrapped cups.
10. The method of claim 9 , wherein the supplying step comprises supplying the pre-made foam cups after the pre-made foam cups have completed any post-forming expansion.
11. The method of claim 9 , wherein the supplying step comprises supplying the pre-made foam cups directly after the foam cups are made.