Search for actuator guidance on conveyor diverters and you will find distributor category pages, generic "types of linear actuators" articles and — genuinely — patent documents. Almost no manufacturer has published engineering guidance for this application, despite it being one of the most common linear-motion jobs in a warehouse.

This guide fills that gap: how to calculate the force, why cycle rate rules out most actuators before force ever becomes the issue, and the mounting mistake that causes the majority of early failures.

Quick answer Force is usually the easy part of a diverter — cartons slide easily. The two specs that actually decide the design are cycle rate (check duty cycle first, before anything else) and side-load protection (never let the actuator rod act as a guide).

Why Diverters Are the Hardest Actuator Job in a Warehouse

A lift table moves a heavy load a few times an hour. A diverter moves a light load constantly, with an impact event on every stroke, in a position where a stoppage blocks the entire line.

Three characteristics make it unforgiving:

1. Cycle count is enormous. A single sortation station can be asked to divert hundreds of items per hour.
2. The load arrives moving. The carton is travelling on the belt when contact happens, so there is an impact component and a lateral component.
3. A failure stops everything downstream. Diverter reliability is line reliability.

The Four Diverter Mechanisms and What Each Demands

Pusher arm (right-angle transfer)

The actuator pushes a plate that shoves the item sideways onto a takeaway lane. Demands: longest stroke of the four options (must clear the full conveyor width), highest side-load exposure, moderate force. Watch for: the rod is fully extended at the moment of maximum lateral disturbance — the worst possible geometry for bending.

Pop-up / lift-and-transfer diverter

The actuator lifts a set of rollers or belts through the conveyor deck to redirect the item. Demands: short stroke (often tens of millimetres), higher force because it lifts the item plus the transfer mechanism itself, and vertical mounting. Advantage: the short stroke gives a short cycle time, which is the single best way to stay inside duty limits. This is usually the highest-throughput option.

Pivoting arm or paddle diverter

The actuator drives a pivoting arm that sweeps items into a lane. Demands: the pivot converts linear travel into angular sweep, so a short actuator stroke produces a wide sweep — mechanically efficient. Force requirement varies with the lever arm ratio. Watch for: the clevis and pin geometry must accommodate the arc; a rigidly mounted rod end will bind.

Shoe sorter and gate mechanisms

The actuator sets a gate or diverting rail rather than touching the product. Demands: lowest force of all, but potentially the highest cycle count, and precise repeatable positioning. Watch for: position feedback becomes valuable here — the FY020 and FY015 pages state feedback sensors and signal-sending limit switches are available; the FY011E page states optional Hall sensors.

How Do You Calculate the Force to Push a Carton Off a Conveyor?

For a pusher sliding an item across a static deck:

Where:

• $\mu$ = coefficient of friction between the item base and the deck surface
• $m$  = item mass (kg)
• $g$  = 9.81 m/s²
• $a$  = required acceleration =  $2s\mathrm{/}{t}^2$  for travel distance  $s$  in time  $t$

Worked example — 20 kg carton, 600 mm transfer, 1.5 s available:

Friction term, taking a conservative  $\mu$  of 0.4 for corrugated board on a worn steel deck:  $0.4\times 20\times 9.81=78.5\text{<br>}$

Acceleration term — accelerate over the first half of the travel:  $a=\frac{2\times 0.3}{{0.75}^2}\approx 1.07{\text{m/s}}^2\Rightarrow 20\times 1.07=21.4\text{ N}$

Subtotal ≈ 100 N. Even doubling that for misalignment, jammed items and a safety margin lands near 200 N — far below the 2,000 N published on our smallest industrial unit, the FY021C.

The lesson: force is rarely the binding constraint on a diverter. Do not select on force. Select on duty and side load.

⚠️ Use your own measured friction coefficient. Values vary widely with deck material, surface wear, contamination and packaging type — a figure that is right for clean stainless and shrink-wrap can be badly wrong for dusty painted steel and corrugated board.

Cycle Rate: the Constraint That Rules Out Most Actuators

Run the duty arithmetic before anything else. Our industrial series publishes 10% duty as 2 min on / 18 min off, which allows about 6 minutes (360 s) of motion per hour.

Cycle times are illustrative, derived from the stroke divided by a mid-range published speed plus reversal allowance — verify against your actual model, load and voltage. Speed falls under load: the FY015 spec table publishes 5 mm/s at 7,000 N versus 160 mm/s at 750 N.

This table explains why pop-up diverters dominate high-throughput sortation and long-stroke pushers are reserved for low-rate stations. If your required rate exceeds the duty allowance, the fix is mechanism selection, not a bigger actuator. Full method in duty cycle for 24/7 warehouse actuators.

Side Load — the Number One Cause of Diverter Actuator Failure

A rod-style actuator is built to take force along its axis. A diverter naturally applies force across it:

• the carton contacts the pusher face off-centre;
• the item is still moving with the belt, adding a lateral component;
• the pusher plate is wide, so any contact away from the centreline creates a moment;
• the rod is at maximum extension — maximum leverage — when contact occurs.

The failure sequence is consistent: bushing wear → rod play → seal deformation → ingress → contamination of the screw → seizure. Nothing about the force rating prevents it.

Design rules that prevent it:

If a diverter has been failing every few months, side load is the first thing to check — before assuming the actuator was underrated.

Speed, Stroke and Mounting Geometry

Stroke. Take the conveyor width, add the pusher plate offset, add clearance so the retracted plate does not foul passing items. Then stop — every extra millimetre of stroke costs you cycle time and duty allowance. Stroke is built to order across our industrial range, so specify the exact figure rather than rounding up to a catalogue size.

Speed. Must complete the transfer inside the window between items. Compute from the line speed and item pitch: if items pass at 0.5 m/s with 1.2 m pitch, the window is 2.4 s, and the transfer must finish comfortably inside it.

Mounting. Retracted length determines whether the actuator fits under or beside the conveyor frame. This is the dimension most often discovered too late — ask for it at the quotation stage together with the stroke.

Environment. Dry indoor sortation: IP65 (available on the FY015, FY015D, FY028). Dusty goods or near a dock door: IP66 (FY020, FY021D, FY021C). Wash-down: IP67 (FY015C, FY011E). Environment mapping in the warehouse IP rating guide.

Specification Checklist for a Diverter Actuator

Mechanism type:          pusher / pop-up / pivoting / gate
Item mass (max):         ____ kg
Deck friction (measured):____
Transfer distance:       ____ mm
Available time window:   ____ s
Diverts per hour (peak): ____
Line environment:        dry indoor / dusty / near dock / wash-down
Available space (retracted length): ____ mm
Feedback required:       none / limit signal / Hall / potentiometer
Supply voltage:          12 / 24 / 36 / 48 / 72 VDC
 Sending this block with an enquiry removes an entire round trip of questions.

Frequently Asked Questions

How much force does a conveyor pusher actuator need? 

Friction plus acceleration, with a margin. For a 20 kg carton over 600 mm in 1.5 s, roughly 100 N before margin — well within the 2,000 N of our smallest industrial model. Force is rarely the constraint.

What limits how fast a diverter can cycle? 

Duty cycle. At 10% duty (2 min on / 18 min off), you have about 6 minutes of motion per hour — roughly 36 cycles at 10 s each. Short-stroke pop-up mechanisms get far more.

Why do diverter actuators fail early? 

Side load on the extended rod. Guide the pusher externally and connect through a floating joint.

What IP rating should I use? 

IP65 for dry indoor lines, IP66 for dusty or dock-adjacent lines, IP67 for wash-down.

Can I get position feedback for a diverter? 

Yes. Feedback sensors and signal-sending limit switches are stated as available on the FY020 and FY015; optional Hall sensors on the FY011E. Confirm the exact type for your controller.

What stroke should I order? 

The minimum that clears the conveyor plus plate offset and clearance. Stroke is made to order, so specify precisely — excess stroke wastes duty allowance.

Send Us Your Diverter Requirement

Give us item mass, transfer distance, diverts per hour and available mounting space, and we will come back with a mechanism recommendation, a model, and the achievable stroke and retracted length.

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