摘要 |
A filter assembly includes a bowl assembly and a head member enclosing a filter cartridge. A filter center tube is permanently fixed to the bowl but allowed to rotate within a pocket in the bottom of the bowl. The top of the center tube is threaded for fastening to a stud on the filter mounting head. The center tube cannot be threaded onto the stud without the filter assembled over the center tube and into the bowl. In order to assemble the bowl to the head, the operator must turn the outside of the bowl. If a filter is not present, the bowl will turn independently of the center tube and no torque is transmitted to the threads. When the filter is properly installed, a series of tabs or features spaced around the inner perimeter of the wall of the bowl interlock with corresponding grooves or features in the outside diameter of the end cap of the filter. Tabs or features on the outer diameter of the center tube also interlock with grooves or features in the inside diameter of the end cap. The interlocking arrangement on the outside diameter and inside diameter of the end cap forms a lock that then allows torque transmission from the bowl, through the end cap, to the center tube. This arrangement permits the threads to engage and the bowl assembly to be installed. <IMAGE>
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