Abstract: A mobile crane includes a main body and extendable axles, which are selectively re-positioned relative to the main body through strategically positioned apertures. The axles may be automatically locked to the main body in a desired one of the multiple positions without operator intervention. The axles one or more tapered ends for connecting to side frames, which may support crawler tracks. The tapered ends of the axles extend through openings located in the frames such that they are removably connected to an outside or exterior portion of the frames relative to the main body.

Abstract: A mobile crane includes a boom extension assembly having a base boom section with a primary shell and a secondary formed shell attached thereto, which allows for selective strengthening along the length of the base boom section. Methods involve manufacturing a boom assembly including such a base boom section.

Abstract: A mobile crane includes a boom extension assembly carried alongside a telescoping boom assembly in a stowed position. The boom extension assembly includes a fly section with a first portion adapted for being connected to the head end of the boom assembly in an operative position while a second portion of the fly section adapted for being connected to the first portion remains in the stowed position. The first portion of the fly section may: (1) be shorter in length than the corresponding second portion of the fly section; (2) include sheaves for supporting a hoist line; (3) include a tapered end; or (4) be used in combination with two additional sections of the boom extension assembly. A related method includes connecting a first, shorter portion of a fly section to a head end of a telescoping boom assembly while a second portion remains in a stowed position.

Abstract: Disclosed are systems and related methods for mounting a ground-engaging motive device, such as a crawler track assembly, to a vehicle, such as a crane or the like, in either an extended or a retracted position. The systems and methods are adapted to ensure that proper alignment is reliably achieved between the mounting structures on the motive device and the corresponding mounting structures on the vehicle in both the extended and retracted positions. In one embodiment, the system and method are especially adapted for use in extending the crawler track assemblies on certain types of existing cranes without the need for extensive retrofitting.

Abstract: A locking and latching system for use with a telescoping boom assembly in a crane or other lifting device is provided. The system may include complementary devices for latching and unlocking a selected boom section for telescoping movement relative to a next-adjacent boom section using an extension cylinder. Preferably, the devices are activated in a predetermined sequence using a single motive device. The motive device may include a single cylinder for performing both the locking and latching function. The locking and latching cylinder may be axially aligned with the extension cylinder to create a relatively compact locking and latching system that easily fits within the confines of the innermost boom section in a conventional boom assembly.

Abstract: A boom assembly for a crane or other lifting device is provided. The boom assembly includes a plurality of telescoping boom sections, each having an at least partially rounded portion, and a plurality of corresponding wear pads for reducing friction between the adjacent boom sections during relative telescoping movement. The rounded portion includes a plurality of equiangular breaks. Each wear pad is substantially identical and includes a contoured engagement surface for positioning adjacent to one of the plurality of breaks at the lower front end of each boom section. The identical wear pads are interchangeable, which eliminates the need for keeping a plurality of substantially different shapes or sizes of wear pads on hand for positioning at the lower front ends of adjacent boom sections. Spacers may also be provided between the wear pads positioned adjacent to the breaks on outer boom sections to prevent shifting during the relative telescoping movement.