Assembling Barrier Arms and Counterweights in the Workshop

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Parking barrier arm assembly in the workshop starts with measuring the opening and the operator's mounting point, then fitting the arm, balancing it with counterweights, and testing the travel before installation. Correct balance and alignment are what keep the motor from overloading and the arm from drifting over time.

Measuring the Opening and Mounting Point

Every barrier job begins on site or from accurate photos. We record the width of the lane, the height the arm must clear, the position of the operator housing and the level of the base plate. These four numbers decide the arm length and the mounting offset, so a small error here carries through the whole build.

Lane width and clearance height
Operator centre line relative to the lane
Base plate level and anchor positions

We write these values in a drawing and a short specification, then the client or engineer approves them before any metal is cut.

Planning the Arm and Counterweight Layout

The arm is planned as a lever. The heavier the arm, the more the operator has to work to lift it, so the counterweight is positioned on the opposite side of the pivot to bring the centre of gravity close to the axis. Our drawings show the pivot point, the counterweight carrier position and the stop positions for both open and closed states.

Arm profile, length and the type of counterweight are chosen together, because a longer arm needs more counterweight to stay balanced.

Cutting, Welding and Pre-Assembly in the Factory

In the Rival Street workshop we cut the arm profile to the drawn length, prepare the mounting plate and drill the pivot holes with a jig so that every hole lands in the same place. Joints are welded and ground flush, then the assembly is dry-fitted on a flat table to check straightness and the position of the counterweight bracket.

Dry fitting is the stage where most small errors are caught, while changes are still cheap.

Balancing the Arm and Setting the Counterweights

Balancing is done with the arm fitted to a test pivot. We lift the arm to the horizontal position and release it. If it drops or rises by itself, the counterweight is adjusted in small steps until the arm stays where it is set. Counterweights are fixed with locking bolts so they cannot shift during operation.

A well balanced arm stops smoothly at both ends and does not slam, which protects the operator and the gearbox.

Finishing and Protection

Once the mechanical layout is confirmed, the arm is finished for the outdoor environment. Steel parts are hot-dip galvanized and then powder coated, and aluminum parts are finished to match the site. Reflective strips and warning colours are applied to the arm according to the client's requirements and the site rules.

Finishing is done after balancing, so any final adjustment does not damage the coating.

Installation and Commissioning on Site

On site we set the base plate level, fix the operator, mount the arm and check the open and closed positions against the drawing. We test the travel several times, check the limit switches and confirm that the counterweight has not moved. The maintenance team receives a short note showing the balance setting and the bolt torque values as checked by the engineer.

Keeping that note on file makes future service much faster.

Frequently asked questions

Why is counterweight balance so important for a barrier arm?

A balanced arm needs less force from the operator, so the motor and gearbox wear more slowly. It also stops safely at each end without bouncing.

Can the arm length be changed after installation?

Changing length alters the balance, so the counterweight must be rechecked. It is best to decide the length during planning and measurement.

How do I know if a barrier arm is out of balance?

Raise the arm by hand to horizontal and let it go. If it falls or rises on its own, the counterweight needs adjustment.

Who checks the final installation against the standards?

We confirm the layout on site, and exact values for the installation are checked with the responsible engineer.

Common mistakes to avoid

Adjusting the counterweight after the finish is applied, and fixing the arm without rechecking the operator centre line, can both cause drift and damage the coating.

Our recommendation

Record the balance setting, the bolt torque and the limit positions in a short note on the first visit, and recheck the balance at every scheduled service.

Summary

Careful measuring, planned counterweight layout, workshop dry fitting and on-site balancing together produce a barrier arm that runs smoothly and lasts.

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