Telescopic Extendable Conveyors: How the Adjustoveyor closes the last 50 feet of the loading dock

By Daniel Hartwell, Senior Systems Engineer, SmartlogitecX

A telescopic conveyor that pushes a moving belt to the nose of the truck, so your team stops carrying cartons and starts placing them. Here is how the machine is built, and how to choose the right one.

Every high volume shipping operation runs into the same bottleneck, and it is almost never the part of the building anyone planned around. Cartons move across the warehouse on a fixed conveyor line without much drama. Then the line reaches the dock door and stops. The last 50 feet, the stretch that runs into the throat of a parked trailer, becomes the slowest and most punishing part of the whole flow. That is the gap where your people walk, lift and stack by hand, often in summer heat, often near the trailer ceiling.

If you load and unload over the road trailers, you already know what that gap costs. It shows up as slower turn times, as injuries to shoulders and backs, and as the door you cannot keep staffed. You can automate everything upstream and still lose the gains at the dock face, because the equipment that carries product the final distance was never built to follow the operator into the trailer.

That is the problem the Adjustoveyor was designed to solve. It is a telescopic extendable conveyor that reaches out from the dock and delivers a moving belt straight into the truck, so cartons travel almost to the operator’s hands instead of being carried there. Stewart Glapat invented the machine in 1946 and has built it in Zanesville, Ohio ever since. The rest of this piece walks through how it works and, more usefully, how to spec the version that fits your dock.

The machine follows your operator into the trailer, so nobody walks the load

Start with what the Adjustoveyor actually changes on the floor. A conventional fixed conveyor ends at the dock leveller. From there, product has to be moved into the trailer somehow, which usually means people. A telescopic conveyor removes that handoff by extending its own belt into the trailer and retracting it as the load builds, keeping the discharge point close to the work the entire time.

The practical effect is that the conveying surface arrives where the cartons need to go. On the loading side, boxes ride the belt to the rear of an empty trailer, and the machine retracts row by row as the trailer fills. On the unloading side, the belt reaches in to meet product at the nose and carries it back to the fixed line. In both directions the operator places rather than carries, which is faster and far easier on the body.

Stewart Glapat builds an indexing feature into its loading machines, branded the Load X Adjustoveyor, that presents product to associates in a smooth and controlled flow rather than letting it surge. The company points to three operational gains from that approach, and they are worth stating plainly:

• A safer, more ergonomic dock: the belt does the travelling and the lifting that a worker would otherwise do by hand, which is the single biggest driver of injury reduction at the trailer face.
• One person across several doors: controlled, indexed presentation means a single associate can keep up with the flow, so labour is not pinned one to a door.
• A decades long service life: the structural build is designed for a low overall cost of ownership measured in decades rather than years, which is where the return on the equipment is made.

A single continuous belt and a nest of steel booms do the hard part

The engineering that makes all of this possible comes down to three systems working together: the booms that extend, the belt that covers the changing distance, and the steel structure that holds a loaded arm steady in mid air.

Nesting booms driven by a gear motor

The reach comes from a nesting boom structure, a set of steel sections built to slide one inside the next like a telescope laid on its side. A gear motor turns a jackshaft, and that jackshaft drives the booms outward when the operator wants reach and pulls them back when the trailer is full and the machine needs to clear the door. The motion is deliberate rather than quick, because every extended section carries weight that hangs out over open floor.

One belt that unspools instead of stretching

The belt is where the design earns its reputation. Instead of a series of short belts handing cartons from one to the next, the Adjustoveyor runs a single continuous loop of fixed length. As the booms extend, that belt routes through a set of internal rollers and unspools across the new distance, then takes the slack back up as the machine retracts. The surface stays flat and stays tensioned, and the belt never has to stretch to cover the gap. That is what lets a machine reach the nose of a trailer and still hand the operator a smooth, level surface to work from.

Structural steel and an eight point suspension

Holding it together is heavy structural steel channel rather than light gauge tube, and the load rides on an eight point suspension system built to manage the cantilevered weight of the booms when they are fully extended. That last point matters more than it sounds. A telescopic conveyor spends much of its working life with a long, loaded arm projecting into thin air, and the suspension is what keeps that arm rigid instead of letting it sag. It is also a large part of why these machines last as long as they do.

Match the boom count to your floor, not just your trailer

The number of booms on a machine is the first specification most buyers settle, because it governs two things at once: how far the conveyor reaches, and how much room it occupies when parked. The useful insight is that those two are linked. Every additional nested section buys more extension and, less obviously, a shorter retracted footprint for the same reach.

Single and double booms for modest reach

Single and double boom units suit standard loading docks where the reach requirement is modest and floor space is not under pressure. A double boom, with two nested sections, handles docks that do not demand a full run into a long trailer. These are the simplest machines to specify and to live with, and they are the natural entry point to the range.

Triple booms as the distribution baseline

Three boom setups are the workhorses of standard distribution. A triple boom is generally the baseline for loading and unloading a standard 53 foot trailer, because three sections give enough extension to reach deep into the trailer while keeping the retracted machine to a sensible length at the door. For most distribution centres moving cartons in and out of over the road trailers, this is the default choice.

Four and five booms when floor space is tight

Four and five boom machines exist for facilities fighting for floor space, and the logic is counterintuitive at first. A five boom unit has five nested sections rather than two, and more sections let the conveyor throw a long arm into the trailer yet collapse into a much shorter, more compact footprint on the warehouse floor. Where a dock limits how far a parked conveyor can intrude into the building, the extra booms buy that room back without giving up reach. The trade is more moving sections to synchronise and maintain, which is why operations choose them deliberately rather than by default.

The options decide whether a standard machine becomes the right machine

Two docks are rarely identical, and the option list is where a catalogue machine becomes a fit for your building. Most of the choices revolve around one question: getting the belt to the right height for the work and the worker, and then keeping that work safe.

Height set by hydraulics

Height is managed with hydraulics. A base lift tilts the whole unit to set the working angle, while a front end stacker works at the nose of the machine, raising or lowering the discharge end on its own. The front end stacker also swings up toward 90 degrees in the retracted position, which keeps the nose clear and prevents clearance problems at the door. Both run on push button controls, so an operator sets the height without stepping away from the work.

Man on Board platforms for the high tiers

Stacking the top rows of a trailer near the ceiling is where shoulders and backs get hurt. The Man on Board option answers that with a powered operator platform that attaches to the unit and rises alongside the belt, lifting the worker to a comfortable height for the high tiers without step stools or overhead lifting. Stewart Glapat builds it with an automatic levelling device that keeps the platform flat without the operator having to manage it.

Gator style declines for manual palletising

At the discharge end, a Gator style decline adds vertical adjustability for building pallets by hand. As a pallet grows taller, the operator uses push button controls to drop or raise the discharge height to match the layer being worked, so cartons arrive at a comfortable level rather than being lifted or set down. It is a small piece of ergonomics that compounds across a full shift.

Fixed or mobile across multiple bays

Finally there is the question of whether the conveyor stays put. Many units are bolted to the floor at a single dock door. Others ride on powered undercarriages that roll laterally along floor tracks, letting one machine and one operator serve several adjacent loading bays. For operations that cannot justify a dedicated conveyor at every door, that lateral movement is often the feature that makes the numbers work.

Controls and safety built to integrate

A telescopic conveyor rarely works alone, so the control package is built to talk to the rest of the building. Speed is governed by variable frequency drives and microprocessors that let the belt match the pace and indexing of the fixed lines and sorters feeding it, and the machines can be wired with programmable logic controllers to sit inside a wider automated flow. Safety hardware is treated as standard rather than an upgrade: emergency stop buttons run the length of the booms, the control system is built around Category 3 safety circuits, and physical guarding covers the pinch points between the telescoping steel sections.

Specify the machine to your dock, then put it to work

Strip away the options and the proposition is simple. The Adjustoveyor is a heavy duty structural steel conveyor that bridges the dock and the trailer and is built to run for decades. The decisions that matter come down to fit: how far the machine has to reach, how much floor it can occupy retracted, how high the belt needs to travel, and whether it serves one door or several.

Before you specify a unit, measure your dock dimensions and confirm the weight capacities your cartons demand, then match those numbers to a boom count and option set. When you are ready, request a quote from SmartlogitecX, or review the Adjustoveyor product range to see the configurations side by side.