Gregory Bores - Prior Lake MN, US
Michael Zabka - Barron WI, US
Ralph Henderer - Minneapolis MN, US
A wafer shipper for stacked wafers provides significantly improved resistance to shock and impact as well as flexibility and tolerance in wafer capacities and guidance in optimal amount of packing material. These characteristics are provided by unique structural configurations that provide rigidity and desirable distribution of impact forces. The shipper has a base and a top cover both of which have a nominal wall that primarily forms all of the features of the respective components. The base has four sides, four corners, and arcuate wall segments defining a wafer stack pocket. The sides are formed of a downwardly extending nominal wall portion and an upwardly extending lip. Both adjoin a nominal wall defining a planar surface that extends around the base and forms a seat for the top cover. The planar surface adjoins the arcuate wall segments and also adjoins the floor of the wafer stack pocket that is also part of the nominal wall. Channels formed from the nominal wall extend downwardly from the floor of the wafer stack. The channels extend primarily radially or chordially. At each of the four corners of the base are shoulders that extend upwardly from the planar seat surface with each of said shoulders extending to the side wall. A feature and advantage of particular embodiments of the invention is the unique form fit whereby impact forces that are received on the corners and/or sides of the top cover are transferred to the base through the top cover to upright portions on the opposite side of the base from where the impact occurs. There is not a direct horizontal shock conduit from the corners or sides of the top cover to the adjacent portions on the base. This provides a significant improvement in the robustness of the container as well as significant improvement in the protection provided to the wafers, as well as much better resistance to unlatching upon such impact. A further feature and advantage of the invention is that in particular embodiments of the invention, an additional set of radially inwardly positioned arcuate wall segments of a lesser diameter are provided. These may cooperated with the first set of arcuate wall segments to provide a double wall for additional strength for resisting fracturing or damage to the wafers during occurrences such as dropping. Moreover, said second wall can be utilized to make a mold for molding a wafer carrier for a first size of wafers convertible into a mold for molding wafer carriers for a second sized of wafers, said second size smaller than the first. The convertible feature can be added by forming the appropriate concentric slots in the mold for the wafer carrier for the first size. Said appropriate concentric slots, are sized for the second size wafers. Suitably sized blanks may be inserted in said slots when the mold is to be used for the first size wafer carrier and the blanks may be removed when the mold is utilized for the second size. More broadly stated a mold for a wafer carrier can utilize separate inserts for converting from a first size pocket to a second size pocket. An aspect of the invention also include the methodology of accomplishing the converting of the mold and of making carriers with the mold.