What Is a Skid-Steer Vertical Lift Path (Hinge Pin Chart)
A skid-steer vertical lift path, also called a hinge-pin chart, shows where the attachment pivot moves as the loader’s arms rise. Use the chart to check height, forward reach, and clearance for a task. It does not show how much weight the machine can safely lift. Confirm the exact model, attachment, and rated operating capacity before working.
Why skid-steer lift-path charts matter
A hinge-pin chart turns lift-arm movement into a picture you can compare with a real job. It helps answer questions such as “Can this loader clear the truck side?” and “Will the attachment reach far enough to dump?” It does not replace the operator’s manual or tell you whether a load is safe.
For generations, operators have judged reach by watching the bucket rise. A chart makes that motion easier to plan before the machine approaches a truck, bin, or other target. I explain it as a geometry guide: it shows where the attachment pivot travels, not what the loader can carry.
That distinction matters. A machine may reach a target but lack the safe capacity to lift the load, especially with a heavy attachment or a load held far forward. A chart from another model can also lead to a poor fit. Start with the chart for the exact machine and configuration.
What a vertical lift path and hinge pin chart show
A vertical lift path is the route the attachment pivot follows as the lift arms move from low to high. The hinge-pin chart plots that route, usually as height against horizontal reach. It may also list maximum hinge-pin height and reach at full height. Those figures describe position, not lifting capacity.
The hinge pin is the pivot point where the loader’s lift arms connect to the attachment carrier. On a chart, the plotted path shows how that point changes position as the arms rise. The attachment itself may extend beyond the pin, so its edge or cutting lip will not sit at the plotted point.
| Chart term | Plain meaning | What to check |
|---|---|---|
| Hinge-pin height | Vertical distance from the stated ground reference to the pivot | Maximum height and the height at the job’s working position |
| Forward reach | Horizontal distance from the chart’s stated reference plane to the pivot | What point the reach measurement starts from |
| Lift path | The plotted route of the hinge pin through arm travel | How far forward the pin sits at the needed height |
| Dump angle | How far the attachment can tip forward to empty a load | The angle available at the lift position you need |
| Rollback angle | How far the attachment can rotate back toward the machine | Whether the load can be held or carried as intended |
Chart layouts and reference points can differ by manufacturer. Read its labels and notes before comparing measurements. The machine’s maximum hinge-pin height does not necessarily equal the height of the bucket edge, forks, or load.
How to read the vertical lift path for loading and placement
Read the chart at the height where the job happens, not only at the top of the lift. First find the required vertical clearance, then check the horizontal reach at that point. After that, consider attachment angle and load limits. The plotted pivot position is useful only when matched to the real attachment and task.
Identify the chart and its reference points
A usable chart should match the machine’s make and model, lift-arm configuration, and relevant tire or track setup. Check whether it describes the machine with a specific attachment or carrier. If the chart’s configuration is unclear, ask the dealer or manufacturer rather than guessing.
Find the axes and units. Height may be shown in inches or millimetres, while reach may use the same or a different unit. Look for a note explaining the horizontal reference plane. A measurement from the front of the tires is not directly comparable to one measured from another point.
Follow the path at the working height
Locate the height needed to clear the target, then trace across to where that height meets the lift-path curve. Read the corresponding horizontal position using the chart’s scale. This gives the hinge pin’s position at that part of travel, not the attachment’s full reach.
A vertical-lift design generally keeps the hinge pin farther forward through the upper part of its travel than a radial-lift design. That can help when placing material over a truck side or into a high container. It does not mean every vertical-lift model has the same reach or capacity.
Check attachment angle and the actual opening
The hinge-pin path does not show the whole outline of an attachment. A bucket, fork frame, or other tool adds length and can change the space needed to enter or clear an opening. Check the attachment’s dimensions and the machine’s stated dump or rollback angles at the relevant lift position.
Measure the target’s height and opening, the approach space, and the distance the attachment must reach. Allow room for the attachment to tilt and for the machine to stop in a stable position. If the chart or manual does not provide a needed dimension, get model-specific guidance rather than estimating from maximum height alone.
| Job check | Compare with | Why it matters |
|---|---|---|
| Truck-side clearance | Hinge-pin height at the needed lift position, plus attachment dimensions | Maximum pin height alone does not show bucket-edge clearance |
| Reach into a bin | Forward reach at the required height and the chart’s reference plane | Reach changes as the arms travel |
| Dumping into a target | Lift position, dump angle, and opening dimensions | The attachment must clear and rotate over the target |
| Carrying a load | Published ROC, attachment weight, and load centre | Reach and height do not establish safe payload |
Use a job example without treating it as a capacity test
Suppose you need to tip a bucket over a truck side. Measure the side height and the available approach distance. On the correct chart, find the lift-path point at the height needed to clear the side, then check whether the pin is far enough forward. Next, verify that the bucket can rotate to dump at that position.
If the path reaches the target, that answers only the geometry question. It does not show that the bucket’s contents are within the loader’s rated operating capacity. A load held forward, a heavy bucket, uneven ground, or sudden movement can affect stability. Use the manual’s capacity and stability guidance for the exact machine and attachment.
Skid-steer setup, chart identification, and safety checks
Before using the chart to plan a job, confirm the machine and attachment details. Then check that the equipment is ready to operate as the manufacturer directs. A correct chart helps with fit and clearance, but it cannot make an incompatible attachment or unsafe setup suitable.
Use this sequence:
- Identify the machine. Confirm the model and lift-arm type. Match the chart to its tire or track configuration where specified.
- Confirm the attachment. Check its weight, dimensions, compatibility, and any required hydraulic connections. Use the operator’s manual for attachment and capacity limits.
- Inspect the connection. Check quick-attach engagement and locking pins. Inspect hydraulic lines and couplers for damage or leaks, and confirm safety interlocks work as directed by the manual.
- Plan the clearance. Measure the target height, opening, approach distance, and required dump angle. Compare these with the lift path at the needed position, not just at maximum height.
- Check the load limit. Find the machine’s rated operating capacity (ROC) in its manual. Account for attachment weight and the load’s position; do not estimate safe payload from hinge-pin height or reach.
- Operate with care. Where practicable, work on firm, level ground. Keep the load low while travelling, raise it only as needed, and keep people clear of the work zone. Follow the manual for slope limits, seat belt, restraint bar, and other safety requirements.
ROC is the manufacturer’s published operating limit for a machine under a stated basis. The test definition and how it applies can vary, so use the definition and instructions for the exact model. Do not assume the full ROC remains available with every attachment or load position.
The critical mistake is treating a hinge-pin chart as a load chart. A heavy attachment, forward load centre, raised load, slope, or sudden movement may increase the risk of a tip-over or dropped load. Never use reach or height as permission to exceed ROC, lift a suspended load, or work under raised arms without the approved support device.
Attachment, hydraulic-system, and machine maintenance
A chart’s usefulness depends on the machine and attachment being in the stated condition and configuration. Wear, damage, a loose connection, or an incorrect tool can affect operation. Follow the manufacturer’s inspection and service instructions, and do not rely on a chart to diagnose a mechanical fault.
Before work, check the attachment and quick-attach components for visible damage and secure engagement. Inspect hydraulic lines and couplers for leaks or wear. Use only compatible attachments and follow the machine’s instructions for hydraulic connections; do not disconnect pressurized lines.
If the arms do not move as expected, stop and consult the manual or a qualified service provider. A chart describes expected geometry; it does not confirm that the lift arms, hydraulic system, or attachment are functioning correctly. Do not modify an attachment or machine to gain reach unless the manufacturer approves the change.
Shutdown, inspection, and storage
At the end of the task, lower the attachment and park and shut down the machine as its manual directs. Before disconnecting an attachment, follow the specified procedure to relieve hydraulic pressure. Inspect for leaks or damage, and use the approved lift-arm support before working beneath raised arms.
For storage, follow the manufacturer’s instructions for the machine and attachment. Keep the chart with the correct equipment records so it is not confused with information for another model. If tires, tracks, lift arms, or attachments change, confirm whether the published chart and capacity guidance still apply.
Frequently asked questions
These short answers clarify what a hinge-pin chart can tell you and where its limits are. Use them as a quick reference, then check the machine’s own chart and operator’s manual for dimensions, capacity, and operating steps.
Is a hinge-pin chart the same as a lift-capacity chart?
No. A hinge-pin chart shows the pivot’s position through lift-arm travel. A capacity chart or manual information addresses load limits. Use the correct model’s ROC and load guidance to judge whether a load is within limits.
What does maximum hinge-pin height mean?
It is the vertical height of the attachment pivot at full lift, measured from the reference stated by the manufacturer. It is not necessarily the height of the bucket edge or the load.
What is forward reach at maximum height?
It is the horizontal distance from the chart’s stated reference plane to the hinge pin when the arms are fully raised. Check that reference point before comparing charts or job measurements.
Does vertical lift always reach farther than radial lift?
No. A vertical-lift design generally keeps the hinge pin farther forward through the upper part of travel, but reach depends on the specific machine and position. Compare the exact model’s chart for the task height.
Can I use a chart from a similar model?
Do not assume it applies. Lift-arm design, tires or tracks, and other configuration details can affect the chart. Use information for the exact model and setup, or ask the manufacturer or dealer to confirm.
Does reaching a truck bed mean the load is safe?
No. Reaching the bed is a geometry check, not a capacity check. Verify ROC and the machine’s load guidance, including the attachment and load position, before lifting.
Why does the attachment’s weight matter?
The attachment is part of the load the machine must handle. Its weight and the load’s position affect the remaining capacity and stability. Use the manual’s guidance for the exact machine and attachment.
What should I measure before checking the chart?
Measure the target height, opening, approach distance, and required dump angle. Also identify the chart’s reference plane and account for the attachment’s dimensions. Compare these with the lift path at the working position.
Does a hinge-pin chart show dump angle?
Not always. Some charts or specifications include dump and rollback angles, but these depend on the machine, attachment, and lift position. Check the relevant documentation rather than inferring angle from the path.
Can I work beneath raised lift arms?
Not unless they are secured with the manufacturer-approved lift-arm support and the manual’s procedures are followed. A chart shows position; it does not support the arms or make working beneath them safe.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
