Connecting rod

#The present invention relates generally to machine elements and, more particularly, to pitmans and connecting rods.

#It is difficult to produce oil and gas in an economic manner from low permeability reservoir rocks. Production rates are often boosted by resorting to hydraulic fracturing, a technique that increases rock permeability by opening channels through which reservoir fluids can flow to recovery wells. During hydraulic fracturing, a fluid is pumped into the earth under high pressure where it enters a reservoir rock and fractures it. Proppants are carried in suspension by the fluid into the fractures. When the pressure is released, the fractures partially close on the proppants leaving channels for oil and gas to flow.

#Specialized pumps are used to develop the pressures necessary to complete a hydraulic fracturing procedure or “frac job.” These pumps are usually provided with connecting rods that join a crosshead to a plunger that pressurizes a fluid. A conventional connecting rod is cast as a single unit and machined to desired tolerances. When portions of such a connecting rod wear out, the rod must be replaced in its entirety—a time-consuming, wasteful and costly undertaking. Multi-piece connecting rods have been developed as a substitute for one-piece rods with the purpose of permitting just the worn portions of a rod to be removed. Unfortunately, multi-piece rods have not gained widespread acceptance since wear has tended to occur not only in the usual locations, but, also, at the junctions between the joined pieces. Thus, the known multi-piece connecting rods, like the one-piece rods they were meant to supplant, often require a full replacement when partially worn.

#The present invention may be more readily described with reference to the accompanying drawings, in which:

#FIG. 1 is a side elevational view of a connecting rod in accordance with the present invention with portions broken away to reveal details thereof.

#FIG. 2 is a top view of the connecting rod of FIG. 1 with portions broken away.

#Referring now to the FIGS., a connecting rod in accordance with the present invention is shown at 10. Connecting rod 10 includes a shaft 12 having major and minor flanges 14 and 16 at its opposed ends. Major flange 14 is configured for attachment to a bearing housing 18 and minor flange 20 is configured for attachment to a crosshead link 20. Link 20 has an alignment plug 22 for insertion into a socket 24 in the center of minor flange 16. A ring 26 is integrally formed with plug 22 and has a transverse aperture 28 for receiving a crosshead pin (not shown). A number of bolts 30 penetrating minor flange 16 and ring 26 releasably fasten shaft 12 and link 20 together.

#Shaft 12 comprises an elongated, hollow tube whose outer and inner diameters vary along its length. As shown, shaft has a cylindrical section 32 with a constant outer diameter from which a gusset section 34 with a gradually increasing outer diameter extends to reinforce major flange 14. A passageway 36 extends through shaft 12 and is enlarged in terms of diameter at both of its ends so as to form sockets 24 and 38 for receiving alignment plugs 22 and 40 of link 20 and bearing housing 18. A peripheral wall 42 extends inwardly from cylindrical section 32 into passageway 36 and serves as an abutment for plug 22 and a reinforcement for shaft 12 adjacent flange 16.

#Major flange 14 is an outwardly projecting rim for strengthening the connection between shaft 12 and bearing housing 18. For compactness, major flange 14 is provided with clipped, linear sides 44 that limit its outward projection from shaft 12 to front and back projections 46 and 48. Projections 46 and 48 are each provided with a plurality of holes 50 arrayed around gusset section 34. The centers of four holes 50 are arrayed to define a square. Through holes 50, bolts 52 are extended for threaded attachment to bearing housing 18.