Abstract: A method and apparatus of adding a DC drive motor to an existing Ward-Leonard motor-generator motion drive for a material handling device which utilizes static power conversion to supply the armature current of the added DC drive motor. Existing drive motors receive their power from corresponding generators which are shaft driven by an AC motor. The added DC motor obtains its power through a transformer which reduces AC line voltage down to the proper level and which is then converted to a variable voltage reversible DC armature supply by a power conversion module. The speed of the existing motors and the added motor is synchronously controlled from an operator's master switch.

Abstract: A control system for a material handling device such as a drag line in which additional power required for a first motion, such as hoisting, may be obtained from the power source for a second motion such as drag and conversely additional power for the second motion may be obtained from the power available for the first motion under specified conditions.

Abstract: A modular construction for a crawler assembly in track-type vehicles and a structural arrangement of the crawler assembly with the vehicle frame are described. In each crawler assembly there is a central side frame member which is integral with the vehicle frame and extends laterally from it for carrying the crawler track in the intermediate portion of its travel. Each central side frame member is equipped with upwardly-extending track support rollers carrying the crawler track while downwardly-extending track rollers are provided for guiding the crawler track and supporting the vehicle on the surface on which it is traveling. The idler roller is carried by a first modular member which is bolted to a first end of the side frame member. A second modular member carrying the crawler sprocket is bolted to the other end of the central side frame member.

Abstract: In an excavating machine having a lower frame, an upper frame and means for rotatably supporting the upper frame on the lower frame, an assembly for improving the load conditions of the upper frame supporting structure comprising an annular seal mounted on one of the upper and lower frames and disposed in wiping, sealing engagement with the other of the upper and lower frames, forming a sealed chamber between the upper and lower frames, and air is supplied under pressure to the chamber to provide an upwardly directed force on the upper frame alleviating the load imposed on the upper frame supporting structure.

Abstract: A method of assembling a gear train including at least two shafts each journaled in at least one gear and bearing, in a support assembly, comprising forming openings in the support assembly having cross sectional areas greater than the cross sectional areas of the bearings, positoning the bearings in the openings, meshing the gears to provide a desired clearance and alignment of the shafts, inserting a moldable, hardenable material in the openings between the support assembly and the bearings and then hardening the material to fix the position of the bearings and, correspondingly, assure the desired clearance of the gears and alignment of the shafts without requiring accurate machining of the openings in the support assembly.

Abstract: An improved boom support for a walking dragline excavator having a roller circle, a frame mounted on the roller circle for swing movement about the axis of the roller circle, a boom having a pair of boom feet connected to a front end of the frame and proximate to a segment of the roller circle, a hoist line connected to hoist machinery on the frame and passing over a point on the boom, a bucket connected to the hoist line, a dragline interconnecting the bucket and drag machinery on the frame, the front end of the frame having insufficient stiffness for adequately resisting deflection and substantially uniformly distributing the boom weight and hoist load imposed thereon over a segment of the roller circle disposed beneath the front end of the frame, the boom support including an upright structure having an upper end and a pair of legs connected to the frame, the upper end of the upright structure being connected to the pendants and to the frame rearwardly of the leg connections, the leg connections of the upr

Abstract: In a machine having an upper moveable frame, a frame for supporting the upper moveable frame including a rigid grid structure, an upper plate disposed on and rigidly secured to the grid structure and a pad for supporting the upper moveable frame, such support pad being disposed unattached to the grid structure and rigidly attached to the upper plate.