What Is A Brush Chipper Feed Control Bar (Safety Trip Rigging)
A brush chipper feed-control bar is the operator’s machine-mounted control for stopping the infeed rollers and, on some models, reversing them. Its bar, pivots, linkage, return parts, and any switches must stay in the configuration set by the manufacturer. It is not a universal emergency-stop device, and it must never be tied back, extended, weighted, or bypassed.
If a manual says “check the trip bar,” you may wonder whether it is a handle, a guard, or a stop switch. The answer matters: the bar is part of a control system designed to change how the chipper feeds material. Its exact action depends on the machine, so guessing at its function or adjusting its linkage can create a serious hazard.
I explain it this way in equipment training: identify what the bar does on that specific model, confirm that it moves and responds as the manual says, and do not alter it. The word “rigging” here refers to the bar and its control linkage, not tree-lifting rigging.
What a Brush Chipper Feed-Control Bar Does
The feed-control bar is an operator control near the infeed area. Moving it tells the chipper to change roller action, usually to stop feeding and, on some machines, to reverse. The bar’s position labels and manual define its function; controls and response vary by model.
The rollers pull branches into the chipper. If the operator needs to stop or back out material, the feed-control system provides a way to change that motion from the designated operating position. On equipped models, a common set of positions is forward, neutral or stop, and reverse. Other control layouts may differ.
The bar’s movement is transferred through parts that may include pivots, rods, cables, springs, switches, or hydraulic and electrical controls. The exact setup depends on the machine. “Trip” describes the control’s movement and response; it does not mean that every bar works the same way or stops every machine function.
The feed-control bar is important, but it does not make it safe to reach into the hopper. Keep your body and clothing clear of the rollers, and use the control only as the manual directs. Key point: treat the manual and the machine’s labels as the authority on what each position does.
What “Safety Trip Rigging” Means
Safety trip rigging is the set of parts that lets the operator’s bar activate its intended feed-control response. It includes the bar, pivots, linkage or cable, return parts, and any connected switches or controls. It is model-specific and must remain configured as the manufacturer specifies.
A bar may look simple, but its action relies on the full assembly. A loose fastener, stuck pivot, disconnected cable, or damaged return part can affect its movement or the response it triggers. An electrical or hydraulic control may also be involved, depending on the design.
Do not add extensions, weights, tie-backs, or homemade linkage. These changes can alter how far or how easily the bar moves, or prevent it from returning as designed. If it trips too easily, feels stuck, or does not trigger the expected response, stop using the chipper and follow the manual’s inspection and service instructions. Do not “fix” nuisance trips by defeating the control.
| Term | Plain-language meaning | What to check |
|---|---|---|
| Feed-control bar | The operator’s control for changing feed action | Labels and intended movement in the manual |
| Linkage | Parts that carry the bar’s movement to a control | Damage, looseness, disconnection, or obstruction |
| Return mechanism | Parts that help the bar return as designed | Free movement and the specified return action |
| Trip response | The machine’s intended reaction to bar movement | The model-specific stop or reverse response |
The table explains common terms, not a universal adjustment guide. Key point: no single bar shape, travel distance, or operating force applies to every chipper.
Equipment Setup and Feed-Control Safety Prep
Before use, set up the chipper according to its operator manual and the worksite rules. Wear the required personal protective equipment, place the machine on stable ground, and keep people clear of the hopper, discharge area, and moving parts. Check guards and controls before feeding material.
Start with the model and serial number. Use them to find the correct manual, since adjustment details and test steps can differ even among machines that look alike. Establish the site’s exclusion zone, manage nearby traffic, and keep bystanders away from the machine’s danger areas.
With the machine secured as the manual directs, inspect the bar and visible parts of its rigging. Look for damage, missing or loose fasteners, a blocked pivot, a disconnected linkage, or parts that do not return as intended. Check that required hopper, feed-table, and discharge-area guards are installed and secured.
Test the control only by the manufacturer’s procedure and from the designated operator position. Confirm that it produces the specified response before feeding material. Do not invent a test, reach into the hopper to check roller movement, or operate with a guard removed or defeated. Key point: if the control fails its prescribed check, do not feed material; consult the manual and qualified service support.
Field Chipping Operation and Safe Material Feeding
During chipping, stay at the designated operator position and use the bar as the machine’s labels and manual instruct. Keep hands, feet, and loose clothing away from the hopper and roller reach. The bar changes feed action; it does not make it safe to hold material near moving rollers.
Feed material in the direction and manner stated in the manual. Some instructions call for feeding branches butt-end first, but follow the specific machine guidance. Let go before the material can pull you toward the hopper. Use the feed control, not your hand, foot, or an improvised tool, to stop or reverse the feed.
Illustrative field scenarios, not reports of specific incidents:
- If a branch begins feeding in a way that feels unsafe, remain in the operator position and use the labeled control as directed. Do not reach toward the rollers to grab or reposition it.
- If the bar feels obstructed or does not produce its expected response, stop feeding. Shut down and isolate the machine as instructed before inspection.
- If material is jammed, do not use the bar as permission to reach into the hopper. Follow the shutdown and energy-isolation steps before clearing it.
A control response is model-specific. Do not assume that “neutral” stops the engine, stops every moving part, or makes a jam safe to remove. Key point: control the feed from the operator position, and keep your body outside the infeed hazard area.
Feed-Bar Inspection, Maintenance, and OEM Adjustment
Inspect and maintain the trip bar only as the manufacturer directs. The operator can check visible condition and movement during the prescribed pre-use check, but adjustment values and service steps are machine-specific. There is no universal travel distance, force, or response time for feed-control bars.
Use this check sequence with the machine secured as required by its manual:
- Inspect the bar, pivots, linkage, cable, fasteners, and return parts for visible damage or interference.
- Check that guards are present and secured, and that control labels are readable.
- Confirm free movement and the specified response using the OEM test procedure.
- Record any fault and take the machine out of service until it is corrected according to the manual.
Do not alter linkage length, add a spring, bend the bar, or substitute parts based on another chipper’s setup. Do not guess at hydraulic pressure or electrical settings. If adjustment or repair is needed, use the model-specific service instructions or a qualified technician.
ANSI Z133 is a relevant safety standard for arboricultural work; follow applicable requirements along with the chipper manual. OSHA logging rules in 29 CFR 1910.266 apply only when the work falls within that standard’s scope. Neither reference supplies one universal trip-bar adjustment for all chippers. Key point: for measurements, test steps, and repairs, use the exact machine documentation.
Shutdown, Cleaning, and Jam Response
Shutdown means more than moving the bar to stop or reverse. Follow the manual’s stopping sequence, isolate the power source, and wait for all moving parts to stop before cleaning or clearing a jam. Use the manufacturer’s energy-isolation procedure, including lockout/tagout where required.
If a bar or linkage is disconnected, stuck, or bypassed, the intended stop or reverse response may not work. If a jam keeps the rollers pulling, reaching into the hopper can expose you to entanglement. Stop the machine, isolate all energy, and verify there is no motion before following the manual’s jam-clearing procedure.
Never reach in while the engine can operate, rollers are moving, or stored hydraulic or pneumatic energy remains unisolated. Do not rely on the feed bar alone to make the machine safe for service. After cleaning, reinstall and secure required guards before returning the chipper to use.
For storage, use the manual’s shutdown and storage directions. Keep controls and labels protected and report damage before the next use. Key point: isolation and zero motion come before clearing, cleaning, or reaching near hazardous parts.
Frequently Asked Questions
Does every brush chipper have a feed-control bar?
No. The bar applies to machines whose manufacturer provides one. Control layouts and functions vary.
Does the bar always stop and reverse the rollers?
No. Some models provide stop and reverse; others may differ. Check the machine’s labels and manual.
Is the feed-control bar the same as an emergency stop?
Not necessarily. Do not assume it stops the engine or every machine function. Use the controls and shutdown procedure specified by the manufacturer.
How far should the bar move?
There is no universal travel distance. Use the specification and test procedure for the exact model.
Can I tie the bar back if it trips too often?
No. Do not tie it back, weight it, extend it, or bypass its linkage. Stop use and find the cause using the manual or qualified service support.
Can I adjust the linkage myself?
Only if the manufacturer’s instructions allow it and you can follow the model-specific procedure. Do not use guessed settings or another model’s dimensions.
What should I do if the bar sticks or fails its test?
Do not feed material. Shut down and isolate the machine as directed, then follow the manual’s service instructions.
Can I clear a jam after moving the bar to stop?
No. Stop and isolate all energy, wait for motion to end, and follow the manual’s jam-clearing procedure before reaching near the hopper.
What does “rigging” mean in this context?
It means the bar and connected pivots, linkage, return parts, and controls. It does not mean lifting rigging.
Which manual details should I look up?
Use the model and serial number to find the correct manual. Check its control labels, inspection steps, test procedure, adjustment guidance, and energy-isolation instructions.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
