Electric mining shovel saddle block assembly with adjustable wear plates

A saddle block assembly including a main body having a shipper shaft opening through the main body bottom end, and an eccentric pin opening in the main body top end, an eccentric pin received in an eccentric pin opening in the top end of the main body, and a wear plate support. The wear plate support has a pin receiving opening, the eccentric pin being received in the pin receiving opening. Wear plates are mounted on the bottom end of the wear plate support and are adapted to bear against the top of a dipper handle.

BACKGROUND OF THE INVENTION

The present invention relates to power shovels and, more particularly, to power shovels having a dipper for excavating earthen material. More specifically, the present invention relates to saddle block assemblies that support the dipper handle or arm.

There are many known earth moving apparatuses or the like. Typical prior art earth moving equipment or excavators use a bucket or dipper assembly, on the end of a movable arm, to scoop earthen material from horizontal or vertical faces. The dipper is normally provided with sharp teeth to dig against the surface being worked. The dipper further includes a cavity for collecting the material so removed. Once the earthen material is received within the dipper, the arm is typically moved to another location for transfer of the material. The material is usually discharged into a dump truck, onto a conveyor, or merely onto another pile of material.

Large electric mining rope shovels utilize a digging attachment comprising a stationary boom and a combination handle and dipper structure that mounts on the boom and that actively crowds and hoists into a bank in order to fill the dipper. As shown inFIG. 2, the handle26comprises two legs68that pass on either side of the boom22. The handle26has gear racking62attached to the bottom of each leg68. A shipper shaft66having an axis58is also mounted horizontally through the boom22. Two pinions70with splines74are attached to the shipper shaft66. The gear racking62on the handle legs68engages the pinion gear splines74. An electric motor and a transmission (not shown) rotate the shipper shaft and pinions, thus causing the handle and racking to crowd and retract from the boom. Two saddle block assemblies78are mounted on the shipper shaft66and are used to keep the handle26in the proper position while the shovel is operating.

During operation the handle sees forces in the vertical and horizontal directions. The vertical force is a result of the separating force between the gear racking on the handle and the crowd pinion, and from digging loads. The horizontal force is due to the machine swinging, digging loads, and from inertia. The purpose of the saddle block assemblies is to withstand these forces and keep the handle in position.

For best operation, there should be only a small gap in between the handle and the saddle block. This gap is ideally between 0.125 inches (0.3175 centimeters) and 0.25 inches (0.635 centimeters). If the gap increases beyond this amount, the system begins to experience a couple of problems. First the gaps between the components contribute to large shock loads as the parts move. Second, a large gap on top of the handle allows the handle racking and the crowd pinion to separate from each other. This greatly increases the load on the gear teeth leading to broken gear teeth, rough operation, and increased noise.

As the saddle block assembly provides support for the handle, the handle is frequently crowding or retracting in order to dig in the bank or to swing the shovel. The relative motion between the components causes wear on the surfaces of the saddle block that are in contact with the handle. The saddle block assemblies are large structures; therefore it is not conducive to replace the entire saddle block assembly because it has wear on a couple of surfaces. For this reason, replaceable wear plates160form a part of the saddle block assembly. The wear plates160are much less expensive and easier to replace than an entire saddle block assembly. After the wear plates160have reached a certain thickness, they are discarded and new ones are installed. This leaves the integrity of the saddle block assemblies intact.

The saddle block wear plates160need to be adjusted on a regular basis to maintain the correct gap between the components. Rather than throw the wear plates160away at every adjustment, they are repositioned to increase their service life. Metal shims164and168are installed between the wear plates160and the saddle block assembly, as shown inFIG. 3, to maintain the proper operating gap. This procedure for adjusting the gap works but is time consuming and difficult. The shims are large but very thin which makes them difficult to handle. It is also awkward to work between the handle and the saddle block assembly. The area is covered in lubricant, the access is poor and the catwalks used to reach this area cannot provide ideal access to the wear plates160. Since the wear plate adjustment is difficult, it may not be performed or it may be performed less frequently than needed.

BRIEF SUMMARY OF THE INVENTION

One of the objects of this invention is to provide a saddle block assembly with an easier method for adjustment of the wear plates by reducing the time needed to make the adjustment.

Another of the objects of this invention is to provide an adjusting saddle block assembly that performs the same function as the existing saddle block assemblies, but does not use shims and has the potential to reduce the maintenance time to adjust the gaps between components.

Another of the objects of this invention is to provide an adjusting saddle block assembly that can have a significant, positive impact on handle racking life and shipper shaft pinion life.

This invention provides a saddle block assembly including a main body having a shipper shaft opening through the main body bottom end, and an eccentric pin opening in the main body top end, an eccentric pin received in an eccentric pin opening in the top end of the main body, and a wear plate support. The wear plate support has a pin receiving opening, the eccentric pin being received in the pin receiving opening. Wear plates are mounted on the bottom end of the wear plate support and are adapted to bear against the top of a dipper handle.

This invention also provides a saddle block assembly including a main body having a top end and a bottom end, the main body having a shipper shaft opening through the main body bottom end. The saddle block assembly also includes a tube-receiving opening through the main body between the main body top end and main body bottom end, and a tube received in the tube receiving opening. There is also means for extending the tube, means for securing the tube in the tube-receiving opening, and a wear plate mounted on the end of the tube.

Illustrated inFIG. 1is a power shovel10. It should be understood that the present invention is capable of use in other power shovels known in the art and the power shovel10is only provided as an example of one such power shovel. The power shovel10comprises a frame14supported for movement over the ground. Specifically, frame14is a revolvable housing mounted on a mobile base such as crawler tracks18. A fixed boom22extends upwardly and outwardly from the frame14. A dipper handle26is mounted on the boom22for movement about a saddle block and rack and pinion crowd drive mechanism30for pivotal movement relative to the boom22about a generally horizontal dipper handle axis32, and for translational (non-pivotable) movement of the dipper handle26relative to the boom22. The dipper handle26has a forward end34. A dipper38is mounted on the forward end34of the dipper handle26in a conventional manner. An outer end42of the boom22has thereon a sheave46, and a hoist cable or rope50extends over the sheave46from a winch drum54mounted on the frame14and is connected to the dipper38.

The saddle block assembly of this invention is shown inFIG. 4. The new saddle block assembly82is substituted for the saddle block assemblies78(seeFIGS. 2 and 3) of the prior art. The saddle block assembly82includes a main body86, two eccentric pins90, means mounted on the main body86for turning the eccentric pins90in unison, a wear plate support or casting94, and upper wear plates100mounted on the bottom end104(seeFIG. 6) of the casting94and adapted to bear against the top surface108(seeFIG. 2) of the dipper handle26. More particularly, the main body86has a top end112and a bottom end114, and a shipper shaft opening118through the main body bottom end114. Two eccentric pin openings116are spaced apart at the top end112of the main body86, and each of the eccentric pins90are received in a different one of the eccentric pin openings116.

More particularly, the casting94has a top end118and a bottom end120, and two pin receiving openings122. The casting94receives a different one of each of the eccentric pins90in each of the pin receiving openings122.

The upper wear plates100are attached to the casting94with bolts (not shown). This casting94is attached to the saddle block assembly82by the two large eccentric pins90. An eccentric pin90(seeFIG. 6) is a pin that has two sections91and92with different diameters that are not concentric. As the gap between the top surface108of the handle26and the upper wear plate100increases due to wear the eccentric pins90are rotated slightly. Since the pins90are eccentric, rotating them will cause a cam action between the pins90and the casting94. This cam action changes the gap between the top surface108of the handle26and the upper wear plate100. When the correct gap is achieved, the eccentric pins90are locked in place until the next adjustment.

More particularly, the means mounted on the main body86for turning the eccentric pins90in unison comprises each pin90having a large sprocket136(seeFIG. 7) mounted on one end of the pin on one side140of the main body86, a small double grooved sprocket144(shown in ghost inFIG. 7) rotatably mounted on the one side140of the main body86, a first endless chain148trained over one of the large sprockets136and the small sprocket144, and a second endless chain148trained over the other of the large sprockets136and the small sprocket144, so that when the small sprocket144is rotated and the chains148are moved, the large sprockets136rotate in unison.

More particularly, each of the large sprockets136is attached to a respective one of the outboard faces152of each eccentric pin90, as shown inFIG. 7. The small sprocket144is keyed to an adjusting pin154. When an adjustment is needed, the large sprockets are unlocked (locking mechanism not shown) and the adjusting pin154is rotated. This rotation causes the chain148to rotate both of the large sprockets that in turn rotate the both eccentric pins90together. The gap between the handle and the upper wear plate100changes due to the cam action of the eccentric pins90in the casting94.

The saddle block assembly82also includes two threaded tube receiving openings128spaced apart in the handle horizontal movement direction. The openings128extend through the main body86between the main body top end112and the main body bottom end114. The assembly82also includes two threaded tubes124, each of which is received in one of the tube receiving openings128, means for turning the tubes124, and means for locking the tubes124in the tube receiving openings128. The saddle block assembly82also includes two lower wear plates132, each of which is mounted on the end of one of the tubes124.

More particularly, when the lower wear plate loses thickness due to wear, a locking key156is removed and the threaded tube124is turned until the correct operating gap is achieved. After the gap is achieved the locking key156is installed again.

This saddle block assembly82differs from the previous saddle block assembly78in a number of ways. The existing saddle block assemblies78used wear plates that were adjusted with shims. The cam adjusting saddle block82uses eccentric pins90for the upper wear plate100and threaded tubes124for the lower wear plate132to adjust the gap. No shims are used to make the adjustment. The upper most wear plates on the existing saddle block assemblies78must be adjusted independently. The cam adjusting saddle block assembly82adjusts both upper wear plates100at the same time. This is due to the adjusting chain and sprocket assembly connected to both eccentric pins90.

The adjusting saddle block assembly of this invention has the potential to reduce maintenance time required to adjust the wear plates. This is due to several reasons. First there are no shims to add or remove. Second both upper wear plates are attached to a casting and adjusted at the same time. Third, all adjustments are made from the outboard side of the saddle block assemblies which provides unobstructed access to all hardware.