Oval Circular Conveyor

An oval circular conveyor is the most widely used closed-loop layout in multi-station assembly: two 180° arcs joined by two straight runs, with carriers circulating continuously past fixed process stations.

It is the default because of what the straight runs do. Stations sit on the straights, where the carrier travels in a single direction at constant attitude, and the arcs exist only to return carriers to the start. For many applications, you will find an oval layout or sometimes the term “circular” conveyor describes this same concept—ultimately, an oval circular conveyor is what most users mean. Nothing about the process has to accommodate the curve.

Where Oval Circular Conveyor fits

Specify an oval loop when the process is a sequence — load, then a run of operations, then unload — and the stations can be arranged along two parallel runs. That covers most assembly, dispensing, pressing, inspection and testing lines. Very often, a solution will call for oval and circular conveyor attributes combined to fit a variety of stations.

Consider a rectangular loop instead when stations must also sit on the short sides, or when the loop has to fit a square machine footprint. Consider a round loop when the process is short enough to fit around a single circle and floor space is the binding constraint. Choosing either a true oval circular conveyor or an alternative depends on your station layout needs.

Configuration of Oval Circular Conveyor 

Performance of precision Oval Circular Conveyor 

Payload is quoted per carrier and depends on guideway width and fixture geometry rather than on mass alone — an overhung or tall fixture consumes capacity through the moment it generates, particularly during deceleration. Our engineering team runs that calculation as part of the quotation. To clarify, payload capacity numbers presented here are based on tests with the oval circular conveyor models configured for assembly stations.

Modular V30 lines carry up to 20 kg per carrier and index down to 0.7 s; modular V50 lines carry up to 50 kg and index down to 0.85 s. Connecting rod drive carries up to 15 kg per carrier. These systems, especially in oval or circular conveyor forms, are engineered for versatility.

Drive options

Timing belt — quiet, smooth, well suited to moderate loads and steady running. Belt drive oval circular conveyor arrangements are frequently used in assembly automation.

Chain — the higher-accuracy option at ±0.03 mm with a positioning mechanism, and the drive used on our modular range at 20 mm pitch. When using a chain drive, oval and circular conveyor designs can achieve excellent repeatability.

Link drive — a linkage giving cam-profiled motion with no impact at index, close carrier spacing, and sectional maintenance access. Older drawings and catalogues call the same drive a connecting rod drive. See Link Drive Circular Conveyor.

Laying out the two runs of Oval Circular Conveyor

The two straight runs are identical as rail and quite different as places to put a process. Three decisions are worth making before the station list is fixed.

Keep load and unload adjacent. One robot, one operator or one transfer unit can then serve both, and the handover to the conveyors either side of the cell happens at one place rather than two.

Separate the two kinds of station. Equipment that brings services and guarding with it — presses, dispensers, robots — sits more comfortably on one run, leaving manual work and inspection on the other. Maintenance access and operator access then stop competing for the same side of the machine.

Hold every station on one pitch grid. Stations land on carrier positions, so a station that wants its own spacing sets the spacing for the whole loop. Where one operation genuinely needs more room than the rest, the usual answer is to leave an empty carrier position beside it rather than to open out the pitch everywhere.

Why we ask for the fixture plate width

Payload is the number customers send first; the fixture plate width along the rail direction is the one that more often decides the layout.

The plate width sets how close adjacent carriers can be, and the arcs are where the limit bites — carriers swing about the centre of the curve, so plates that clear each other on the straight can converge at the arc. A close pitch and a small arc diameter therefore pull against each other, and the resolution is a larger arc, a narrower plate, or link drive, which is built around close carrier spacing.

Our engineering team works that geometry per line; the published dimensional and selection data sits on our technical site. What this page asks for is simply that the plate envelope goes into the enquiry alongside the weight, because it chooses the arc as often as the payload does.

Mounting for Oval Circular Conveyor

Horizontal is the standard arrangement. Vertical mounting is available and changes the load picture materially — gravity moves from the carrier’s strongest direction into its weaker one, roughly halving the available static capacity. A fixture that runs comfortably on a horizontal oval may need a wider guideway or a reduced payload vertically, so the mounting orientation should be settled before the line is sized rather than after. For demanding installations, the mounting method should match the exact configuration of the oval circular conveyor.

Dual rail of Precision Oval Circular Conveyor

An oval can be built as two parallel loops carrying one fixture between them. That is the arrangement for fixtures that are wide across the rail direction, or heavy enough that a single carrier would be working against its moment limit rather than its load limit. A vertically mounted double-track heavy-load line has been delivered.

Joints on the two rails are staggered so that a carrier crosses one interface at a time. We do not publish synchronisation or parallelism figures for twin-rail loops; they are confirmed per line.

Scope of supply of Precision Oval Circular Conveyor

A quoted line covers the guideway, arcs, carriers, drive element and drive unit, positioning mechanisms and the frame — board-type or aluminium profile. Servo motors and drives are supplied to the plant’s preferred brand where there is a standard, and pneumatic cylinders as AirTAC, SMC or a brand you specify.

The plant provides the mounting surface, compressed air where cylinder positioning is used, power, and the line controls unless the line is quoted with them. The mounting surface carries a flatness requirement, because a loop twisted in its frame shows up as inconsistent positioning rather than as anything obviously mechanical — the specification is published with the joint data on our technical site.

Engineering data

Dimensional tables, selection arithmetic and assembly detail are published on our technical site: All specifications are for TallMan’s modern circular conveyor layouts, including load and cycle time.

• Elliptical Track Set Dimensions — assembly dimensions for every published combination
• Conveyor Cycle Time Calculation — station pitch against cycle time
• Conveyor Slide Load Calculation — carrier load factor
• Circular Conveyor Loop Parameters — turning a station count into a line length

Enquiries

Send fixture envelope and weight, required cycle time, station count and mounting orientation. Non-standard arc diameters, straight lengths and track shapes are all available to suit your ideal oval circular conveyor.

Frequently asked questions about Oval Circular Conveyor

Can stations be added to an oval loop after it is running?

Adding a positioning station to an existing straight run is usually possible, and adding carriers is a configuration change rather than a rebuild. What does not move is the carrier pitch — it is set by the drive element, so a new station has to land on an existing pitch position. If it cannot, the drive element and every carrier mounting are re-pitched, which is close to a new loop. Where the process is expected to grow, the cheap insurance is to specify the straight length and the pitch for the final station count and commission the first build with fewer carriers.

Can one carrier be stopped while the others keep moving?

No. Every carrier is attached to the same drive element, so they index together and stop together. What is available is independent timing at the station rather than at the carrier: individual cylinder positioning clamps and releases each station on its own signal, so one station can hold its carrier through a longer operation while the loop waits in position. If the process genuinely needs carriers moving at different times, the architecture to look at is a linear motor transport system, and our comparison page sets out that trade honestly.

Does the arc diameter matter if no stations sit on the arcs?

It does, in three ways that all land on the layout rather than on the process. The arcs set the machine’s width and add to its length, so they decide whether the loop fits the cell. They limit how close the carriers can be, because of how fixture plates behave around a curve. And they cap speed through the turn, since a tighter curve reaches its limit sooner than an open one. A loop that has to be fast and compact at the same time is the case where those three pull hardest against each other.

Which run should load and unload sit on?

Whichever side faces the rest of the plant. The loop’s handover to upstream and downstream equipment happens at those positions, so putting them on the run nearest the aisle — and next to each other — keeps one piece of handling equipment serving both and keeps material flow off the maintenance side of the machine. It is a decision that costs nothing at layout stage and is awkward to reverse once the frame and guarding are built.

What does the plant have to prepare before installation?

A mounting surface flat enough that the loop is not twisted into it, compressed air if the line uses cylinder positioning, power for the drive, and access around the outside of the loop for the process equipment. The frame is part of our supply unless the line is going onto an existing machine base, in which case we need that base drawing early — a loop designed around a base we have not seen is the most common cause of a fit problem on site.

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