| 摘要 |
An earth boring bit has a bearing seal that floats to accommodate angular and axial movement of the cutter 31 with respect to the shaft 15. The seal is located in an annular groove 17 formed in the shaft 15. A supporting ring 23 is located in the groove 17. The supporting ring 23 has an inner diameter larger than the inner diameter of the groove 17 to provide a clearance for allowing the supporting ring to float. An elastomeric ring 29 is located on the outer circumference of the supporting ring 23. The supporting ring 23 presses the elastomeric ring into sealing contact with the cutter. A backing ring 27 is provided between the elastomeric ring 29 and one wall of the groove 17, the back-up ring 27 preventing cuttings formed during boring operations from coming into contact with the elastomeric ring 29. The ring 29 is under compression between the back-up ring 27 and the opposing wall of the grooves. <IMAGE> |
