Concrete Demolition Pulverizer

Overview

A concrete demolition pulverizer is a jaw attachment that hangs from the dipper of a tracked excavator in place of the digging bucket. It breaks reinforced concrete by closing a powerful moving jaw against a fixed one, cracking the concrete into small pieces that fall away and exposing the steel reinforcing bar, which integral blades then cut. Unlike a hydraulic breaker, which hammers from the top down and throws dust and fragments, a pulverizer squeezes a section at a time, so it works quietly and keeps the rubble close to the jaw. That makes it the usual choice for top-down demolition of slabs, columns, and bridge decks where dust and flying debris have to be controlled.

The attachment is built around five working groups. The Mounting Bracket hangs it from the excavator, the Rotation Assembly turns it to line up on any face, the Main Jaw Frame carries the Fixed Jaw and the pivot, the Moving Jaw Arm swings in to crush, and the Closing Cylinder supplies the closing force. The Wear and Cutting Set takes the abrasion and is replaced as it wears, and the Speed Valve Block controls how fast the jaw closes.

Mounting to the excavator

The Mounting Bracket is a welded Hitch Bracket bracket bored to match the carrier's dipper and bucket link. Two hardened Mount Pin pins carry the load, and a Pin Bushing at each joint takes the wear so the bracket itself lasts. A set of Lateral Shim plates take up side play so the attachment does not rock on its pins. The same bucket cylinder that would curl a digging bucket now drives the pulverizer's rotation oil and, through the carrier auxiliary line, its crushing cylinder. Matching the pin spacing and pin diameter to the carrier class is what keeps a 30 t pulverizer from being hung on a 14 t machine that could not hold it up or feed it enough oil.

Rotation

The Rotation Assembly lets the operator turn the jaw a full 360 degrees so it can grip a wall, a floor edge, or an overhead beam at the right angle without repositioning the whole machine. A Rotation Motor of the gerotor type drives a hardened Drive Pinion that meshes with the toothed Slew Ring. Inside the motor a Gerotor Set turns oil flow into the high torque needed to swing a heavy jaw, and the Slew Bearing carries the crushing reaction loads while the jaw rotates, riding on rows of Ball Bearing rollers between the ring and the Slew Race. Because the jaw spins continuously, oil reaches the closing cylinder through a Rotary Swivel rotary union rather than fixed hoses that would twist off.

Jaw frame and crushing arm

The Main Jaw Frame is a welded Weld Body in high-strength plate that ties the coupler, the rotator, and the jaw pivot into one rigid structure. The Fixed Jaw is the stationary half that concrete is crushed against, and welded Reinforcing Gusset plates stiffen the body so the two jaws do not spread apart under load. The Moving Jaw Arm swings on a large Pivot Pin running in a renewable Pivot Bushing. The Jaw Arm carries a forward Jaw Tip that bites into a slab edge to start a crush, and a Cylinder Pin links it to the cylinder rod through its own Rod-End Bushing.

Teeth, blades, and wear

The Wear and Cutting Set is the part of the attachment that wears out and is designed to be rebuilt in the field. Bolt-on Crushing Tooth teeth concentrate the jaw force onto small areas so the concrete cracks rather than just being squeezed. As the concrete breaks away it leaves the reinforcing bar bridging the jaws, and hardened Rebar Cutter Blade cutters set at the jaw throat shear that bar so the rubble separates cleanly from the steel for recycling. The jaw faces are protected by bolt-on Wear Plate plates in Hardox 500, and every tooth, blade, and plate is held by a high-grade Blade Bolt so a worn part can be unbolted and swapped on site instead of welding on new tooling.

Hydraulics and control

Crushing force comes from the Closing Cylinder, a large-bore unit with a honed Cylinder Tube and a chromed Piston Rod driving the Piston Head. Its Cylinder Seal Kit and Oil Seal wiper hold pressures of 280 to 350 bar against shock and grit. The Speed Valve Block is what makes the attachment productive: a Regeneration Valve recirculates oil to close the jaw quickly while it meets little resistance, then drops out so the full pump pressure reaches the piston for the crush. A Relief Valve caps the pressure to protect the cylinder and carrier, Check Valve checks hold the jaw if carrier flow stops mid-crush, and a Pressure Sensor reports the crushing pressure. Heavy shock loads work grease out of the joints, so the Lubrication System system feeds a Grease Block that splits grease through Grease Line hoses to a Grease Fitting at each pin and bearing.