A swivelling dumping car carries a bin that can rotate or tip sideways relative to its rail chassis to discharge material. The calculator isolates the gravitational moment of the entered payload about an illustrated horizontal tipping axis.
Swivelling Dumping Car Interactive Calculator
Vary payload mass and two entered horizontal moment arms. Results show load weight and the low, midpoint and high ideal payload moments after sorting the entered offsets.
Equation Used
- Payload mass is treated as a point resultant under standard gravity.
- Each entered offset is a horizontal perpendicular distance to the vertical payload-weight line of action.
- The two offsets are sorted only to display a low-to-high scenario bracket.
- Bin self-weight, latch force, friction, adhesion, changing CG, impacts, track slope and structural capacity are omitted.
How a Swivelling Dumping Car Discharges
The historical mechanism uses a rail chassis and a body arranged to swing or tip sideways for discharge without removing the car from the track. Stops, pivots and a retaining or release arrangement govern the motion.
Hiscox identifies the swivelling dumping-car arrangement. The entered payload and offsets are calculation scenarios rather than dimensions or load ratings of that historical car.
What This Explanatory Model Is Useful For
The calculator supplies one term for preliminary free-body reasoning: ideal payload weight times its horizontal perpendicular distance from the illustrated tipping axis.
It does not determine whether the bin will release, self-start, complete discharge, stop safely or return. Those behaviors depend on the complete machine and load state.
Ideal Payload Moment
MIT and NASA mechanics references define moment magnitude as force times perpendicular distance to the force line of action. For vertical payload weight and horizontal moment arm e:
The sign and actual arm change with bin position and payload migration; this calculator reports only positive magnitudes at entered arms.
Worked Example: Entered Payload Scenario
For 800 kg payload, load weight is about 7,845 N. Entered horizontal arms of 30 and 40 mm give ideal payload moments of 235.4 and 313.8 N·m, with midpoint 274.6 N·m.
Those values omit bin weight and every resisting or dynamic term, so they are not a self-dump or equipment-capacity result.
Model Boundary
- Calculated: entered payload weight and its ideal static moment magnitude at two entered horizontal arms.
- Historical arrangement: the cited collection identifies a swivelling dumping-car arrangement.
- Not calculated: bin and hardware weight, total CG, latch release, stops, friction, adhesion, load shift, discharge path, acceleration, impact, return effort, rail stability, structure or safe payload.
Frequently Asked Questions
Does positive payload moment guarantee self-dumping?
No. It must overcome all opposing moments and constraints through the actual motion.
Why sort the two offsets?
They are independent entered scenarios; sorting creates a low-to-high display regardless of entry order.
Does the model include the empty bin's center of gravity?
No. Only the entered payload is represented.
Does the moment stay constant while dumping?
No. The moment arm and payload distribution generally change with angle and material flow.
Can the result size the latch or stop?
No. Those require complete static and dynamic load cases.
Does it establish safe payload?
No. Use manufacturer documentation and qualified engineering for the actual car.
References
- Gardner D. Hiscox, Mechanical Movements, Powers, Devices and Appliances: historical swivelling dumping-car entry.
- MIT OpenCourseWare, Static Equilibrium—Force and Moment: moment as force times perpendicular distance.
- NASA Glenn Research Center, Torque (Moment): force, pivot and perpendicular moment arm.
- MIT OpenCourseWare, Rotational Dynamics: moment arm, torque direction and dependence on reference point.
Resources for an actuator-driven tipping design
An actuator-driven tipping design needs a complete load path and mounting geometry. This payload-moment calculator does not determine actuator force or stroke. Those depend on the pin positions, changing moment arm, bin weight and other resisting loads through the motion.
With leverage, force is traded against travel. A bracket change that improves force can also increase required stroke, slow the output motion, or move the actuator into a poor mounting angle.
The review should include the load direction, the bracket spacing, and the point in the travel where the linkage has the least mechanical advantage. If the actuator is selected from only an average force value, the design can pass an early spreadsheet check and still fail in the real assembly.
- Calculate actuator force at the worst bracket angle, not just at mid-stroke.
- Check stroke, retracted length, and extended length against the mechanism envelope.
- Confirm the structure can accept the higher loads created by a stronger actuator.
For a FIRGELLI actuator application, run the FIRGELLI actuator force calculator, then compare available stroke, force, and mounting envelope in the FIRGELLI linear actuator range. If the goal is to replace an existing unit, use the linear actuator replacement finder before assuming the new actuator is a direct fit.
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