Abstract: A top drive well drilling unit which is connected to the upper end of a drill string to drive it rotatively in drilling a well and is movable upwardly and downwardly with the string along a guide structure, and which is provided with pipe handling mechanism beneath the drilling unit for making and breaking a threaded connection between the drilling unit and the string and including an elevator which can suspend a section of drill pipe or the entire string when disconnected from the drilling unit.

Abstract: A slip unit for releasably supporting a well pipe, including a support structure to be positioned on and turn with a rotary table and preferably taking the form of a slip bowl, and a vertically movable slip carrier structure suspending a number of pipe-gripping slips and adapted to be releasably retained by latch means in a lower active position, with the carrier and slips being yieldingly urged upwardly to inactive positions when the latch means are released. The support structure and carrier structure are both desirably formed of complementary sections hinged for relative swinging movement between closed positions about the pipe and open positions permitting movement of the unit laterally relative to the pipe, and with an additional latch being provided for retaining the structures in their closed positions.

Abstract: A well slip assembly including a support structure adapted to be placed on a well drilling rotary table and to turn therewith, a vertically movable slip suspending carrier structure, latch means for releasably retaining the carrier structure and slips in a lower active position relative to the support structure, and yielding means urging the carrier structure upwardly to a retracted position. The support structure is desirably formed separately from a slip bowl structure positionable in the rotary table. The carrier structure may be urged upwardly by fluid pressure type spring means, such as air springs, with an accumulator chamber for the pressure fluid system preferably being contained in or carried by the vertically movable slip carrier structure.