Abstract: A high production dragline bucket which has a low profile in the back wall as well as fewer components than those commonly in use. The bucket is not only lower in production costs, but has higher operating efficiencies. It is adaptable to both single or double sheave dumping assemblies. A replaceable basket portion for the bucket is also described.

Abstract: A gear cutting tool has a series of separate cutter inserts removeably clamped to the front ledge of a holder block. Each cutter insert has a forward cutting edge that extends beyond the ledge and a rear positioning portion that includes a central projection extending rearwardly from side faces. The central projection mates with a respective one of a series of parallel tracks formed in the holder block and the rear faces mate with upright front walls at the rear of the ledge on either side of the track. The arrangement precisely locates the cutter insert in the holder block. The holder block may be formed of a single piece or may be built up of identical interlocking block elements.

Abstract: A roller circle for hoisting and excavating equipment has upper and lower spaced annular rails. A plurality of tapered rollers are disposed between the rails in rolling contact with bearing surfaces of the rails. Each of the rollers is mounted on a shaft. Inner and outer cages connect the projecting ends of the shafts and are joined together by through rods. A portion of the inner cage overlies a side face of a rail and a pad is disposed between the inner cage portion and the side of the rail. A second pad is disposed between the outer cage and the larger ends of the rollers. Thrust loads are transferred from the rollers to the outer cage and through the rods to the inner cage and then to the rail.

Abstract: A high production dragline bucket which has a low profile in the back wall as well as fewer components than those commonly in use. The bucket is not only lower in production costs, but has higher operating efficiencies. It is adaptable to both single or double sheave dumping assemblies. A replaceable basket portion for the bucket is also described.

Abstract: A drive system comprising an endless tread belt made up of identical tread belt links and a cooperating drive tumbler is disclosed. The link is formed with a ground engaging bottom face, a drive wheel engaging top face, and connecting ears along its forward and aft sides which are suitable to interdigit with the ears of other links so as to form a belt. The link also has a guiding cog rising upwardly from the central region of the top face, a bearing surface on each lateral side of the guiding cog, aligned drive surfaces on the forward and aft sides of the guiding cog located between the link bottom face and link top face, and a slot in alignment with the drive surfaces.

Abstract: A closed loop hydraulic swing circuit is provided with crossover auxiliary actuating connections between the pump control lines and the system relief valves to cause the relief valves to open at lower than maximum system pressure in an unloading action that limits braking when a coasting load is causing the motor to return more fluid than the pump can accept.

Abstract: A maximum lift system for a hydraulic hoe includes a dual pressure relief valve in the hoist circuit and an actuating valve that delivers a signal to the relief valve to increase hoist capacity and simultaneously causes operation of lockout valves to center the wrist control valve and thus lock the dipper in position.

Abstract: A motor drive system for a mining shovel includes three a.c. motors which are driven by associated inverter circuits that receive power from a common d.c. bus. The d.c. bus connects to the a.c. power lines through a rectifier circuit and large variations in power occur during various portions of the digging cycle. To limit the peak power demanded during a digging cycle a peak power limiter system comprised of a fourth inverter driven a.c. motor is attached to the d.c. bus. This a.c. motor drives a flywheel which is operated to store energy during periods of low power demand and which is operated to regenerate stored energy to the d.c. bus when power demanded from the a.c. power lines exceeds a preset amount.

Abstract: A marine crane includes a high speed winch having a hydraulic heave compensating system that automatically controls the crane winch to compensate for the vertical movement of a load during offloading operations. The heave compensating system includes a reversing valve for overriding manual control and for directing control pressure to stroke the pump of a hydrostatic winch drive into its raise mode of operation, and a compensating valve that regulates the displacement of the pump permitting it to develop and maintain only a predetermined pressure in the high pressure main fluid line. The heave compensating system preferably includes a lift control system for automatically hoisting a heaving load only at or near the crest or trough of a wave.

Abstract: A tread belt drive system for heavy mobile equipment includes an endless tread belt made up of a plurality of identical links joined together by link connecting pins. Each of the links has a ground engaging bottom and a top having a cog, or cog portion, positioned medially of the link ends, which cog has fore and aft driving surfaces. A pair of longitudinally extending tumbler rim and roller engaging surfaces which extend above the cog are positioned on the top of the link, one on each side of the cog. The links have fore and aft pin connections with the pin center below the engaging surfaces in alignment with the driving surfaces. The drive system also includes rollers which support the weight of the equipment and drive and idler tumbers each having a rim and teeth.

Abstract: A front end mechanism for an excavating machine is shown having a boom pivotally mounted at its foot and a dipper stick pivoted to the forward end of the boom that carries a dipper at its outer end.

Abstract: A motor drive system for a mining shovel includes three a.c. motors which are driven by associated inverter circuits that receive power from a common d.c. bus. The d.c. bus connects to the a.c. power lines through a disconnect switch and a rectifier circuit and a chopper circuit is employed to dissipate power when the d.c. bus voltage rises due to motor regeneration. A power monitor and control circuit monitors the a.c. line voltage and the d.c. bus voltage and it controls the various system elements in such a manner as to maintain the d.c. bus voltage within an operating range. When the d.c. bus voltage cannot be maintained within the operating range, the disconnect switch is enabled to shut down the machine.

Abstract: A boom useful in dragline excavators, cranes and similar machines has a set of longitudinal chords defining a length along the boom and a plurality of lacings connecting the chords. These chords and lacings define a first boom section having a first pair of laterally spaced polyhedron subsections and a second boom section having a second pair of laterally spaced polyhedron subsections, the second pair of subsections being positioned longitudinally with respect to the first pair of subsections. In one embodiment, the polyhedron subsections of each boom section have transverse cross sections in the form of right triangles, with one triangle inverted with respect to the other to form a rectangular-shaped boom. Also, one boom section is reversed end to end with respect to the other boom section to have an inner chord in a subsection on one side of the first boom section in alignment with an inner chord of a subsection on the opposite side of the second boom section.

Abstract: A marine crane having an upper works rotatably mounted on a pedestal adapter, includes a retainer for limiting the extent to which the upper works can be tilted, such retainer having an arcuate member secured to the upper works that extends partially around the pedestal adapter and presents a lip beneath and out of contact with a stationary circumferential member forming a part of the pedestal adapter. The arcuate member has a series of vertical, plate-like buttresses spaced along its circumferential length that have outer ends facing a machinery deck of the upper works to brace the arcuate member, so as to retain the arcuate member in place in the event of abnormal forces being applied thereto.

Abstract: A hydrostatic winch having a hydraulic drive system with a dual control valve which adjusts pressure in control lines for varying the speed of lowering and hoisting a load and a brake for stopping the load has an overspeed control system which includes first valve means for relieving pressure in the control lines and first valve control means which opens the valve to automatically slow the speed of the winch when the load is moving too fast and a fail safe system for smoothly stopping the load, if necessary, which includes a braking system having a normally "off" brake which is biased towards an "on" position but which is held in the "off" position by a hydraulic cylinder.

Abstract: A dragline has two booms at a ninety degree angle with the dragrope between them. Each boom has a variable speed hoist mechanism and both hoist ropes are connected to the bucket. Either boom can be used as a digging boom, with the other serving as a dumping boom, and relative hoist speeds are controlled to move a filled bucket to a dumping position under the dumping boom and back to start position under the digging boom.

Abstract: A control is disclosed for inhibiting the tilting of an earth drilling machine that is supported on hydraulic jacks. A hydraulic downfeed motor for the drill string is operated by a control that has pressure responsive switches connected to the hydraulic jacks, and in the event the drilling machine starts to rise upwardly during drilling one of the pressure responsive switches will operate to shut off fluid pressure to the downfeed motor and to entrap fluid within the motor. The entrapment of fluid in the motor maintains a drilling pressure that permits drilling to continue with a drilling force that will not allow the machine to rise upwardly on the supporting jacks.

Abstract: An improved mounting arrangement for the vertical cylinder of an extensible outrigger assembly includes laterally extending plates on the cylinder that are connected to the beam side walls by two transverse mounting pins, one of which also functions as a connection point for the horizontal cylinder that actuates the outrigger beam. In the preferred embodiment, the vertical cylinder has a self-storing float and a piston rod that is held against rotation to assure correct alignment of the float.

Abstract: A boom point sheave assembly has a sheave shaft which extends transversely of the boom point pivotally mounted at its center in the boom point. Each end of the sheave shaft extends beyond a side of the boom point and rotatably mounts a sheave. A torque rod having one end anchored to the boom point and its other end fixed to the sheave shaft exerts a restoring torque on the sheave shaft should the sheave shaft pivot away from its normal horizontal position.

Abstract: A multi-section telescopic boom has sections with reinforced I-beam side walls and top and bottom walls made up of truss members. The trusses and beam stiffeners are disposed interiorly of the beam flanges so that the flanges provide continuous upper, lower and side bearing surfaces engageable with wear pads all of which are on the next outermost section. The lower and side wear pads are elastomer backed and the side pads have backup buttons that can easily be shimmed out to compensate for wear.