Abstract

In an air circulatory system (10) of the cab (11) of an earthmoving vehicle it is desirable to have a source of ambient fresh air (A) combined with existing cab air (R) flowing through the air conditioning unit (22). It is common practice to pass both sources of air through one filter which adversely affects the effectiveness of the air conditioning unit 22. When separate filters are provided for each source of air, however, serviceability has often been sacrificed by having the filters placed in a location that is not easily accessible. The air circulatory system (10) of this invention overcomes these problems by providing two filters (30,32) which are cooperatively mounted within an assembly 28 that directs the first ambient source of air A through both filters (30,32) while providing a chamber (90) which mixes the cabin air (R) with the ambient and directs the combined air only through the second filter (32). The chamber (90) provides a passageway (100) that is sufficient in size to provide an adequate air flow through the air conditioning unit (22) at all times. The filter assembly (28) is provided with mounting guides (64,66,107,108) which allow the filters (30,32) to be easily serviced from a common service point without concern for the destruction of seals (44,128) that are bonded to each filter (30,32) to prevent the ingress of air which has not been filtered.