What Large Machined Parts Are Involved in Knuckle Boom Cranes with Stamping Variable Amplitude

The large machined parts involved in knuckle boom cranes with stamping variable amplitude are the most core, load-bearing, and precision-demanding parts of its structure. The processing quality of these parts directly determines the performance, reliability, and lifespan of the entire crane.

1. Turntable and Slewing Bearing Connection Seat
This is the core foundation component connecting the upper rotating part and the lower chassis. It is a large box-shaped or disc-shaped structure, the upper surface of which needs to be precision machined to install the slewing bearing, and the lower surface or inner cavity is connected to the slewing mechanism.
Processing Content: Large vertical lathes process the upper and lower joint surfaces to ensure extremely high flatness and parallelism; CNC boring and milling machines process the bolt hole system and positioning shoulder for installing the slewing bearing to ensure the positional and dimensional accuracy of the hole group.

2. A-Frame and Variable Amplitude Cylinder Hinge Seat
As the core support structure of the variable amplitude mechanism, the top of the A-frame is equipped with lugs or supports hinged to the variable amplitude cylinder.
Processing Content: The coaxial pin holes on the double lugs (or single lug) at the top are critical. It is necessary to complete the processing in one clamping on a large CNC boring and milling machine to ensure strict coaxiality and center distance tolerances of the two or more sets of hinge holes, so as to ensure that the cylinder is not strained after installation and the force is evenly distributed.

3. Hinge Shaft Holes Between Multi-Section Booms
This is the most critical and difficult processing point that distinguishes knuckle boom cranes from straight boom cranes. Each boom section has huge, thick hinge lugs at the head and tail.
Processing Content: The pin shaft holes on these lugs are large in size and require extremely high precision. Large CNC floor-type boring machines or gantry machining centers must be used to simultaneously process the holes of multiple sets of lugs in one clamping, strictly ensuring coaxiality, parallelism, and hole spacing. Any deviation will cause the boom to jam during folding/unfolding, generate additional bending moments, and accelerate wear.

4. Large Pin Shaft
Although it seems to be a "shaft", the oversized pin shaft used to connect the boom and cylinder is itself a very important machined part. They are usually forged from high-strength alloy steel.
Processing Content: The outer circle needs to be processed by a large horizontal lathe to ensure diameter dimensional accuracy and surface finish; internal lubricating grease channels may also need to be processed; the surface of some pin shafts will be heat treated (such as carburizing, quenching) to increase wear resistance, and subsequent fine grinding is required to achieve the final dimensions.

5. Cylinder Support
Local supports mounted on each boom section to connect the cylinders that control its movement.
Processing Content: The hinge holes of these supports also require high-precision boring to ensure that their spatial position relationship with the hinge holes of the boom body completely conforms to the design, ensuring that all forces are transmitted along the design direction.

6. Linkage Mechanism Hinge Point
In complex knuckle boom mechanisms, multi-link mechanisms often exist to achieve specific motion trajectories.
Processing Content: The connecting heads at both ends of the connecting rod and their pin shaft holes also require precision boring to ensure the relative positional accuracy between multiple connecting rod hinge points, otherwise it will seriously affect the kinematic performance of the entire mechanism.