RETAINER NUT LOCKING APPARATUS AND METHODS

1 . A lock assembly for retainer nuts on fluid ends, comprising:

a frame, the frame comprising one or more first openings formed therethrough;

one or more inserts, each insert of the one or more inserts being disposed in a first opening of the one or more first openings formed in the frame; and

one or more insert retainers each having a locking tab protruding into one of one or more slots of each insert to limit rotation of the insert about a longitudinal axis of the insert, the one or more insert retainers being fastened to the frame.

2 . The lock assembly of claim 1 , wherein each insert of the one or more inserts is cylindrical and comprises one or more slots, each slot of the one or more slots having an inward lip and an outward lip.

3 . The lock assembly of claim 2 , wherein the locking tab is movable relative to the insert between the inward lip and the outward lip of the slot.

4 . The lock assembly of claim 3 , wherein the locking tab comprises an inward surface and an outward surface, and the inward surface is in contact with the inward lip of the slot.

5 . The lock assembly of claim 4 , wherein each insert retainer of the one or more insert retainers is arcuate in shape and comprises a top end above the insert and a bottom end below the insert.

6 . The lock assembly of claim 2 , wherein:

each insert of the one or more inserts comprises a first outer surface and a second outer surface disposed inwardly of the first outer surface;

each slot of the one or more slots is formed in the first outer surface; and

the second outer surface is hex in shape.

7 . The lock assembly of claim 6 , wherein the first outer surface of each insert of the one or more inserts is disposed in a first opening of the one or more first openings, and each insert retainer of the one or more insert retainers partially surrounds the first outer surface.

8 . The lock assembly of claim 1 , wherein each insert of the one or more inserts comprises an inward end, an outward end, and a magnet coupled to the inward end.

9 . The lock assembly of claim 8 , further comprising a handle coupled to the outward end of each insert of the one or more inserts.

10 . The lock assembly of claim 8 , wherein the frame comprises one or more second openings formed therethrough, and a magnet coupled to the frame through each second opening of the one or more second openings.

11 . A fluid end, comprising:

a fluid end body, the fluid end body comprising an outer surface;

a plunger disposed at least partially in the fluid end body;

a bore formed in the fluid end body;

a retainer nut disposed at least partially in the bore, the retainer nut comprising

an inner tool interface; and

a lock assembly, comprising:

a frame, the frame comprising a first opening formed therethrough,

an insert disposed in the first opening formed in the frame and into the inner tool interface of the retainer nut,

an insert retainer having a locking tab protruding into a slot of the insert to limit rotation of the insert about a longitudinal axis of the insert, the insert retainer being fastened to the frame.

12 . The fluid end of claim 11 , wherein:

the insert is cylindrical and comprises a slot, the slot comprising an inward lip and an outward lip;

the insert retainer comprises a locking tab protruding into the slot; and

the locking tab of each of the insert retainer is movable relative to the insert between the inward lip and the outward lip of the slot.

13 . The fluid end of claim 12 , wherein the locking tab of the insert retainer comprises an inward surface and an outward surface, and the inward surface is in contact with the inward lip of the slot.

14 . The fluid end of claim 13 , wherein the insert retainer is arcuate in shape and comprises a top end above the insert and a bottom end below the insert.

15 . The fluid end of claim 12 , wherein:

the insert comprises a first outer surface and a second outer surface disposed inwardly of the first outer surface;

the slot is formed in the first outer surface; and

the second outer surface is hex in shape.

16 . The fluid end of claim 15 , wherein the first outer surface of the insert is disposed in the first opening, and the insert retainer partially surrounds the first outer surface.

17 . The fluid end of claim 11 , wherein:

the insert comprises an inward end, an outward end, and a magnet coupled to the inward end; and

the frame comprises a second opening formed therethrough, and a magnet coupled to the frame through the second opening.

18 . The fluid end of claim 17 , further comprising a handle coupled to the outward end of the insert.

19 . The fluid end of claim 17 , wherein the frame comprises an outward surface and an inward surface, the insert retainer is fastened to the outward surface, and the magnet coupled to the frame is disposed between the inward surface of the frame and the outer surface of the fluid end body such that the inward surface is disposed at a gap from the outer surface of the fluid end body.

20 . A method of installing a lock assembly to a fluid end, comprising:

providing a frame having a first opening formed therethrough;

disposing an insert into the first opening of the frame, the insert having a first slot and a second slot;

fastening a first insert retainer to the frame and at least partially around the insert, the fastening the first insert retainer to the frame comprising:

inserting a locking tab of the first insert retainer into the first slot of the insert;

fastening a second insert retainer to the frame and at least partially around the insert, the fastening the second insert retainer to the frame comprising:

inserting a locking tab of the second insert retainer into the second slot of the insert; and

inserting the insert into an inner tool interface of a retainer nut disposed in a fluid end body of the fluid end.