Hill, H., "The Case 621 Wheel Loader," SAE Technical Paper 900888, 1990, doi:10.4271/900888.
The 621 is the first of the new Case “21 Series” Wheel Loaders. At 116 net horsepower and with bucket capacities of 2.00 to 2.75 cubic yards, it features a cab located on the rear mainframe and a z-bar loader linkage. The 621 is the culmination of a customer-based development program and is representative of J I Case Company's continuing focus on productivity and durability in its products.It was designed with the operator in mind, thoroughly considering ergonomics and visibility. The 621's loader and vehicle performance, dynamic stability and responsive steering lead to short cycle times and high productivity.The product development cycle of the 621 was reduced to two-and-one-half years through the application of simultaneous engineering and manufacturing concepts.As a result of an extensive, statistics-based field and laboratory demonstration test program, the 621 offers improved reliability over its predecessor, the W20C.