Crane Concrete Bucket

Overview

A crane concrete bucket, also called a concrete skip, is a bottom-dump container that a crane carries to pour concrete where a pump or chute cannot reach. The crane lifts the filled bucket to the placing point, the placer opens a gate at the bottom, and concrete discharges under gravity straight into the forms. It is the standard way to place concrete on sites without a pump: column pours, isolated footings, lift shafts, congested decks, and remote or low-volume work.

Capacities run from 250 L for small hand-managed buckets to 2000 L for large powered units. The bucket is a lifting accessory, not a powered machine: it has no engine and no drive, so it depends entirely on the crane to move it and on a simple, reliable gate to control the pour. Its value is that it turns any crane into a concrete placing tool.

Conical Hopper Body

The Conical Hopper Body holds the charge. Its Conical Shell Plate rolled and welded steel cone, 3 to 5 mm wall, tapers down to the outlet so the concrete funnels to the gate under its own weight. A Top Stiffening Ring stiffening ring at the rim keeps the cone round and carries a removable Top Fill Grate grate that screens the charge as it is loaded from a chute or pump. An internal Internal Wear Liner wear liner reduces concrete sticking to the wall and slows abrasion, which matters because dried concrete left in the cone reduces capacity and adds dead weight.

Stiff or low-slump mixes can arch and bridge above the gate rather than flow. A Vibrator Mount Pad mount lets an attachable vibrator be clamped to the cone to break the arch and keep the discharge flowing.

Discharge Gate

The Discharge Gate Assembly is the part that makes a concrete bucket useful: it seals the cone for transport and meters the pour. A Discharge Gate Blade wear-resistant blade slides or swings across the outlet, closing against a machined Gate Sealing Seat seat. Gate Guide Track guide tracks keep the blade aligned to the seat, a Gate Edge Seal rubber edge seal stops grout leaking past the closed gate, and O-Ring Set seals close the pivots and pins. The gate must open against the full head of concrete above it, so the blade, seat and tracks are sized to slide cleanly even when the bucket is full.

Gate Actuation

The Gate Actuation System system opens the gate against that head. Small buckets use a simple Operating Lever hand lever that the placer cracks open to feed concrete. Larger buckets add a Geared Handwheel geared handwheel so the gate can be opened with low effort and held part-open for steady flow, working through a Gate Linkage bell-crank linkage with a Position Detent detent that holds set openings. Powered buckets fit a Hydraulic Gate Cylinder hydraulic cylinder so the gate can be operated remotely. The point of all three is the same: give the placer fine, repeatable control of the discharge rate rather than an all-or-nothing dump.

Discharge Spout

Below the gate the Discharge Spout & Control hardware directs the pour. A fixed Steel Discharge Spout steel spout concentrates the stream. For deep forms, columns and congested reinforcement, a Flexible Elephant Trunk flexible elephant trunk, secured with Hose Clamp clamps, extends the discharge down into the form to limit free-fall segregation. A Rubber Control Sleeve rubber control sleeve at the outlet lets the placer pinch the flow to start, slow and stop a fine pour by hand, which is how a single placer manages placement around bars and embeds.

Crane Suspension

The Crane Suspension Gear gear is how the crane carries the bucket and how it stays a controlled lift. A Lifting Bail bail spans the bucket top and balances the load to a forged Master Lifting Eye master eye at its apex. A Lifting Sling sling and Connecting Shackle shackles connect the bail to the crane hook, and a Anti-Spin Swivel anti-spin swivel lets the placer turn the bucket to face the pour without twisting the hoist rope. Every element here is a rated lifting accessory certified to the lifting code, because a full 2 m3 bucket carries nearly five tonnes of concrete over the heads of the placing crew.

Support Frame and Use

The Support Frame & Feet lets the bucket stand on its own between lifts. Three Stand Leg legs on Ground Foot Pad pads hold it upright and clear of the ground so it can be filled and the gate accessed, fixed together with a Fastener Set. A Gate Area Guard guard around the gate and linkage protects the placer at the discharge.

In use the cycle is simple. The bucket stands on its legs and is charged through the fill grate from a truck chute or pump. The crane lifts it to the placing point. The placer, riding a platform or working from the deck, positions the spout or trunk, then opens the gate with the lever, handwheel or cylinder and meters concrete into the form, closing the gate when the pour for that spot is done. The bucket returns to the charging point and the cycle repeats. Throughput depends on the crane cycle time and bucket size, but a 1 m3 bucket on a tower crane will place roughly 10 to 20 m3 per hour, enough for column and footing work where a pump would be uneconomic.