Equalizer with lubrication

An equalizer for a mining machine includes an equalizer main body, an internal chamber defined by the main body configured to retain lubrication, and a bushing disposed within the internal chamber. The bushing includes an opening. The equalizer further includes a pin disposed partially in the internal chamber and extending through the opening.

BACKGROUND OF THE INVENTION

The present invention relates to the field of earthmoving machines. Specifically, the present invention relates to an equalizer for a mining shovel.

A conventional rope mining shovel includes a boom, a handle moveably coupled to the boom, a dipper that is coupled to the handle, an equalizer that is coupled to the dipper, and a hoist rope that is coupled to the equalizer. The hoist rope passes over a boom sheave coupled to an end of the boom, and is reeled in and paid out by a hoist drum. The equalizer aligns the hoist rope to be tangent to the boom sheave, reducing wear on the rope. The equalizer is a plate fabrication, having a plurality of apertures and windows for weld access.

During a hoist phase, the rope is reeled in by the hoist drum, lifting the dipper upward through a bank of material and liberating the material to be dug. To release the material disposed within the dipper, a dipper door is pivotally coupled to the dipper. When not latched to the dipper, the dipper door pivots away from a bottom of the dipper, thereby freeing the material out through a bottom of the dipper.

SUMMARY

In accordance with one construction, an equalizer for a mining machine includes an equalizer main body that is a single cast piece, an internal chamber defined by the main body configured to retain lubrication, and a bushing disposed within the internal chamber. The bushing includes an opening. The equalizer further includes a pin disposed partially in the internal chamber and extending through the opening.

In accordance with another construction, an equalizer for a mining machine includes an equalizer main body, an internal chamber defined by the main body, a bushing disposed within the internal chamber, the bushing including an opening configured to receive a pin, a pin extending through the opening, an end cap coupled to the main body, a sealing structure coupled to the end cap and pressed against the pin, and lubrication sealed within the internal chamber.

DETAILED DESCRIPTION

FIG. 1illustrates a power shovel10. The shovel10includes a mobile base15, drive tracks20, a turntable25, a revolving frame30, a boom35, a lower end40of the boom35(also called a boom foot), an upper end45of the boom35(also called a boom point), tension cables50, a gantry tension member55, a gantry compression member60, a sheave65rotatably mounted on the upper end45of the boom35, a dipper70, a dipper door75pivotally coupled to the dipper70, hoist ropes80(one shown), a winch drum (not shown), a dipper handle85, a saddle block90, a shipper shaft95, and a transmission unit (also called a crowd drive, not shown). The rotational structure25allows rotation of the upper frame30relative to the lower base15. The turntable25defines a rotational axis100of the shovel10. The rotational axis100is perpendicular to a plane105defined by the base15and generally corresponds to a grade of the ground or support surface.

The mobile base15is supported by the drive tracks20. The mobile base15supports the turntable25and the revolving frame30. The turntable25is capable of 360-degrees of rotation relative to the mobile base15. The boom35is pivotally connected at the lower end40to the revolving frame30. The boom35is held in an upwardly and outwardly extending relation to the revolving frame30by the tension cables50, which are anchored to the gantry tension member55and the gantry compression member60. The gantry compression member60is mounted on the revolving frame30.

The dipper70is suspended from the boom35by the hoist ropes80. The hoist ropes80are wrapped over the sheave65and are coupled to an equalizer110, which is coupled to the dipper70. The hoist ropes80are anchored to the winch drum (not shown) of the revolving frame30. The winch drum is driven by at least one electric motor (not shown) that incorporates a transmission unit (not shown). As the winch drum rotates, the hoist ropes80are paid out to lower the dipper70or pulled in to raise the dipper70. The dipper handle85is also coupled to the dipper70. The dipper handle85is slidably supported in the saddle block90, and the saddle block90is pivotally mounted to the boom35at the shipper shaft95. The dipper handle85includes a rack and tooth formation thereon that engages a drive pinion (not shown) mounted in the saddle block90. The drive pinion is driven by an electric motor and transmission unit (not shown) to extend or retract the dipper handle85relative to the saddle block90.

An electrical power source (not shown) is mounted to the revolving frame30to provide power to a hoist electric motor (not shown) for driving the hoist drum, one or more crowd electric motors (not shown) for driving the crowd transmission unit, and one or more swing electric motors (not shown) for turning the turntable25. Each of the crowd, hoist, and swing motors is driven by its own motor controller, or is alternatively driven in response to control signals from a controller (not shown).

With reference toFIG. 2, the dipper70includes a first mating projection115(e.g., a lug) and a second mating projection120(e.g., a lug) that each extend from a back wall125of the dipper70. The equalizer110is generally disposed between and is coupled to the first and second mating projections115,120.

With reference toFIGS. 2-4, the equalizer110includes a main body130that is a single cast piece having a first end135and an opposite, second end140. The cast piece does not include apertures or holes for weld access. As illustrated inFIGS. 3 and 4, the main body130defines an internal chamber145that is open at the first end135. The chamber145is formed during the casting process. A pin150extends through the first end135and into the open chamber145. In the illustrated construction, the pin150is an induction hardened pin having an end155that projects out of the main body130and fits into one of the first and second mating projections115,120. Other constructions include different types, shapes, and sizes of pins150than that illustrated.

With continued reference toFIGS. 3 and 4, the equalizer110includes a bushing160disposed within the chamber145. The bushing160includes an opening165to receive the pin150, and to facilitate rotation of the pin150relative to the main body130. In the illustrated construction the bushing160is a standard manganese bushing, although other constructions include different bushings. For example, in some constructions the bushing160is a plain spherical bushing.

With continued reference toFIGS. 3 and 4, the equalizer110includes an end cap170coupled to the first end135of the main body130. In the illustrated construction, the end cap170is a generally disc-like structure having an outer diameter that is identical or substantially identical to an outer diameter of the first end135of the main body130. However, other constructions include different shapes and sizes than that illustrated.

As illustrated inFIGS. 3 and 4, the end cap170includes an outer circumferential surface175that faces away from the first end135, and a smaller, inner circumferential surface180that faces toward the first end135. In the illustrated construction, a first sealing structure185(e.g., polyurethane, etc.) is provided along the inner circumferential surface180within a circumferential notch190in the end cap170. When the end cap170is coupled to the main body130(e.g., with fasteners or other structures), the first sealing structure185presses against the first end135, thereby sealing the end cap170to the main body130.

With continued reference toFIGS. 3 and 4, the end cap170further includes a recess195defined by a first circumferential surface200that extends transverse to both the outer circumferential surface175and the inner circumferential surface180, and a second circumferential surface205that extends parallel to both the outer circumferential surface175and the inner circumferential surface180. The recess195extends circumferentially about the pin150.

With continued reference toFIGS. 3 and 4, the equalizer110includes a seal carrier210disposed at least partially within the recess195. The seal carrier210includes a carrier body215, and a second sealing structure220(e.g., polyurethane, etc.) provided within a circumferential notch225in the carrier body215. The second sealing structure220is a piston seal that presses against the pin150, thereby sealing the seal carrier210to the pin150. As illustrated inFIGS. 3 and 4, the seal carrier210is a floating radial seal, in that there remains a radial gap230in the recess195between the carrier body215and the first circumferential surface200. The seal carrier210therefore “floats” within the recess195, and remains sealed against the pin150even if the bushing160, for example, experiences radial wear (e.g., in some instances up to an inch) and the pin150deflects radially in one direction.

With continued reference toFIGS. 3 and 4, the end cap170further includes a third sealing structure235(e.g., polyurethane, etc.) that is provided within a circumferential notch240along the second circumferential surface205. The third sealing structure235is a face seal that presses against the carrier body215of the seal carrier210, thereby sealing the end cap170to the seal carrier210.

With continued reference toFIGS. 3 and 4, the equalizer110includes lubrication245(illustrated schematically inFIG. 3generally as a pool or collection of lubrication within at least a portion of the internal chamber145). In some constructions, the lubrication245is oil, although other constructions include different types of lubrication (e.g., grease, etc.). The lubrication245is free to flow, for example, around and alongside the pin150, and into spaces between the pin150and the bushing160and generally throughout the internal chamber145.

While only one end of the equalizer110is illustrated inFIGS. 3 and 4, the equalizer110of the illustrated construction is symmetrical about a plane extending transverse to an axis250(FIG. 3) that passes through both the first and second ends135,140and through the pin150. Thus, all of the features illustrated inFIGS. 3 and 4are also present at an opposite end of the equalizer110, such that the internal chamber145is an internal, central space within the equalizer110that is large enough to contain lubrication245for lubricating bushings160at both ends of the equalizer110.

With continued reference toFIGS. 3 and 4, the first sealing structure185, the second sealing structure220, and the third sealing structure235work in conjunction to seal the lubrication245within the equalizer110and within the internal chamber145. Thus, even if the lubrication245flows axially past the bushing160, the lubrication245will be inhibited or prevented from escaping past the end cap170.

In some constructions, the lubrication245moves from one end of the equalizer110to the other, or from one location in the equalizer110to another, based purely on movement of the shovel10itself, or upon movement of the pin150and the main body130. Thus, at least in some constructions, the equalizer110does not include a mechanism to generate movement of the lubrication245. Additionally, the lubrication245slows the wear of the bushing160, the pin150, and/or of other components and surfaces within the equalizer110. Thus, the equalizer110requires less maintenance and down-time as compared with an equalizer110without the added lubrication245.

FIGS. 5 and 6illustrate an equalizer310according to another construction. Similar to the equalizer110, the equalizer310includes a main body330that is a single cast piece having a first end335and an opposite end (not shown). The main body330defines an internal chamber345that is open at the first end335. The internal chamber345is formed during the casting process. A pin350extends through the first end335and into the open chamber345. The equalizer310also includes a bushing360disposed within the chamber345. The bushing360includes an opening365to receive the pin350, and to facilitate rotation of the pin350relative to the main body330. The equalizer310also includes an end cap370coupled to the first end335of the main body330. The end cap370includes an outer circumferential surface375that faces away from the first end335, and a smaller, inner circumferential surface380that faces toward the first end335. The end cap370further includes a recess395defined by a first circumferential surface400that extends transverse to both the outer circumferential surface375and the inner circumferential surface380, and a second circumferential surface402that extends parallel to both the outer circumferential surface375and the inner circumferential surface380. The recess395extends circumferentially about the pin350.

With continued reference toFIGS. 5 and 6, the equalizer310includes a sealing structure405disposed at least partially within the recess395. In the illustrated construction, the sealing structure405includes a corrugated, polyurethane body410that is coupled (e.g., vulcanized) at a first, radial outer end415(FIG. 6) to the first circumferential surface400, and is coupled (e.g., vulcanized) at a second, radial inner end420(FIG. 6) to a metal rail425. In the illustrated construction the metal rail425has a U-shaped cross-section defining a notch430. The notch is sized and shaped to receive a further sealing structure (e.g., polyurethane, etc. not shown), which extends out of the notch430and presses against the pin350.

With continued reference toFIGS. 5 and 6, the equalizer310also includes lubrication (not shown) disposed within the internal chamber345of the main body330. In some constructions, the lubrication is oil, although other constructions include different types of lubrication (e.g., grease, etc.). The lubrication is free to flow alongside the pin350, and into spaces between the pin350and the bushing360.

With continued reference toFIGS. 5 and 6, the sealing structure405(and further sealing structure) seals the lubrication within the equalizer310and within the internal chamber345. Thus, even if the lubrication445flows axially past the bushing360, the lubrication445will be inhibited or prevented from escaping past the end cap370.

Similar to the equalizer110, in the equalizer310all of the features illustrated inFIGS. 5 and 6are also present at an opposite end of the equalizer310, such that the internal chamber345is an internal, central space within the equalizer310that is large enough to contain lubrication for lubricating bushings360at both ends of the equalizer310.

FIGS. 7-9illustrate an equalizer510according to another construction. Similar to the equalizers110and310, the equalizer510includes a main body530that is a single cast piece having a first end535and an opposite end (not shown). The main body530defines an internal chamber545that is open at the first end535. The internal chamber545is formed during the casting process. A pin550extends through the first end535and into the open chamber545. The equalizer510also includes a bushing560disposed within the chamber545. The bushing560includes an opening565to receive the pin550, and to facilitate rotation of the pin550relative to the main body530. The equalizer510also includes an end cap570coupled to the first end535of the main body530. The end cap570includes a thrust plate574and a radial seal (e.g., elastomeric)578coupled to the thrust plate574. In the illustrated construction, the thrust plate574is formed at least partially from MoS2, and includes mounting apertures582for insertion of screws or other fasteners to affix the thrust plate574to the main body530. Other constructions include different materials, as well as different locations for mounting apertures582than that illustrated. As illustrated inFIG. 8, the equalizer510also includes a garter spring586that assists in pressing the radial seal578against the pin550, and an O-ring590that is coupled to a radially exterior surface594of the thrust plate574.

With reference toFIG. 9, in the illustrated construction, the equalizer510further includes a spacer element598(illustrated schematically) disposed within the internal chamber545at the first end535. The spacer element598is disposed between the end cap570and the bushing560. The spacer element598may be welded in place or otherwise inserted and/or affixed in place, such that the spacer element598inhibits or prevents the bushing560from moving and sliding toward the radial seal578. In the illustrated construction, the spacer element598is a spacer plate. In other constructions, the spacer element598is a snap ring, rope bead (e.g., welded to an inside of the equalizer main body530), or other element that inhibits or prevents the bushing560from moving and sliding toward the radial seal578.

While various constructions of sealing structures have been described above for the equalizers110,310,510, in other constructions the equalizers110,310,510include other sealing structures or combinations of sealing structures (e.g., O-rings, gaskets, etc.) to seal lubrication within the equalizer110,310,510.

Although the invention has been described in detail with reference to certain preferred constructions, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.