626 



THE INDIA RUBBER WORLD 



[August 1, 1919. 



Balanced Packing-Box Construction. 



THE INVESTIGATIONS of balanced packing-box construction and 

 tests to determine box design conducted during the war by 

 the Forest Products Laboratorj' contributed in' marked 

 degree to the safe and economical 

 movement of munitions and supplies 

 to the American Expeditionary 

 Forces. Immense monetary savings 

 were effected by the correct construc- 

 tion of containers as to materials 

 used, cargo space conserved, and re- 

 duction of loss by breakage of 

 packages. 



The methods employed to attain 

 these results are now available for 

 general commercial purposes through 

 the services and publications of the 

 Forest Products Laboratory, which 

 continues to investigate the resources 

 of forest products in their relation to 

 many important industrial develop- 

 ments too numerous to mention. 



IMPORTANCE OF BOX INDUSTRY. 



The importance of the box indus- 

 try is but little appreciated. United 

 States Forest Service data shows that 

 the manufacture of packing boxes, 

 shocks, crates, crating, fruit and 

 vegetable packages and baskets, is the 

 second largest wood-consuming in- 

 dustry in the United States, and that 

 in 1912, 11.6 per cent of all lumber 

 produced in the country was con- 

 verted into boxes. 



There are innumerable special de- 

 mands for boxes and crates, but on the whole it is the manufac- 

 turing industry and intensive fruit-raising and market-gardening 

 which creates the demand for boxes. 



Di.'\GONAL Compression Test, 



than is necessary to balance the average strength in every other 

 part. The data for designing such a box cannot be obtained 

 from observation in actual commercial service, because the ob- 

 server sees the box only after it has completely failed and conse- 

 quently cannot measure the hazard which completes the failure. 

 On the other hand, laboratory studies combine practical expe- 

 rience, which is a knowledge of the designs in use, of what lum- 

 ber is available, and of box factory practices, with accurate 

 scientific tests made on the package itself, packed as in actual 

 service and subjected to strains that approximate actual trans- 

 portation conditions. 



TESTS TO DETERMINE A GOOD BOX. 

 Compression-a!ong-an-edge test, as its name implies, is a 

 steady and constantly increasing pressure (measured in pounds) 

 applied along any edge and with the opposite edge diagonally 

 through the box in direct line with the pressure exerted. The 

 corner-wise test is applied in the same 

 way to any corner of the package with 

 the opposite corner in a direct line with 

 the pressure. These two tests measure 

 the strength of the box in withstanding 

 any external pressure and to a limited ex- 

 tent approximate the hazard of the lower 

 HIS of boxes in a pile. By themselves 

 liLse tests are insufficient to determine 

 comparative weaknesses in the various 

 factors that enter into properly balanced 

 construction. 



Another is the drop test, for comparing 

 the strength of one box with that of an- 

 other. The box is packed with the actual 

 contents as in service and dropped from a 

 predetermined height directly on the cor- 

 ner, which is a fall that occurs in actual 

 service. The value of the conclusions is limited, however, be- 

 cause one failure runs so rapidly into another that the observer 

 does not always get the true measure of the weaknesses. 



Exterior View of 14-Foot Drum Box-Testing Machine, 



TERioR View of Drum, Showing Package Construction Test. 



WHAT IS A GOOD BOX? 



A properly designed packing box has enough strength in each 

 part for the intended purpose and no more strength in any part 



The most practical method yet devised is the revolving drum 



Wi». 



