US Patent 7635034 Spring load seal assembly and well drilling equipment comprising same

A top drive apparatus for a well drilling head comprises a top drive structure, a seal body and a plurality of resilient members. The top drive structure is configured for being fixedly attached to an upper end portion of a bearing assembly and having a seal-carrying portion. The seal body has a mounting portion and a wiper portion extending from the mounting portion. The mounting portion is slideably disposed within a groove of the seal-carrying portion of the top drive structure. The plurality of resilient members are disposed within the groove between the mounting portion of the seal body and the top drive structure such that the entire seal body is resiliently displaceable with respect to the top drive structure.