The excavator-style curved boom design on Caterpillar’s E-Series machines provides additional clearance over obstacles while digging a trench or truck loading. The narrow boom enhances the viewing area to the bucket and trench throughout the entire operating range. It features box section fabrication with thick wear plates for performance and durability.
The Volvo backhoe boom design employs an arched shape that is both narrow and tall. Arch designs are inherently strong, and have traditionally been used in bridge and building construction. The upper and lower end caps on the boom are designed to carry the high stress loads from the pivot pins and distribute them smoothly and evenly throughout the boom.
Another key criterion determined by boom geometry is bucket rotation. “Bucket rotation is very important if you want to scrape or dig,” notes Bargellini. “[Volvo’s] bucket rotates 205°, which is about the maximum industry standard.”
Similarly, a single-pin bucket linkage on the Caterpillar E-Series allows 205° of bucket rotation, while serrated edges on the stick provide improved material clamping.
Another component critical to performance is the backhoe swing casting. The casting on the E-Series features replaceable bushings for durability and service.
Volvo concentrated effort on the swing pivot design. “We are unique in the industry in that we place our swing cylinders on top,” says Bargellini. “We get them away from the dirt, which means longer seal and cylinder life. We also have a yoke on both the upper and lower hinge pivots. We use huge bushings on both pivots.”
Even the design of the boom lock can differentiate the backhoes. “The Volvo boom lock is spring applied and pressure released,” says Bargellini. “It is really easy to actuate by simply pushing the pilot control towers away from the operator. ”
“Safety is always the first concern with Terex,” adds Wright. “The Terex boom and swing locking system offers swing and boom lock at a touch of a button, and all from within the cab.”