Historical rock drills used several valve arrangements to alternate working fluid around a reciprocating member. Hiscox includes a tappet valve for a rock drill, while patents document mechanically operated tappets and fluid-distributing valves in differing layouts.
Tappet Valve for a Rock Drill Interactive Calculator
Enter a pressure coordinate and two rate anchors. The calculator performs linear interpolation or extrapolation and reports direct time conversions.
Equation Used
- A straight line is imposed between the two entered anchors.
- Rate is clipped at zero after interpolation or extrapolation.
- Cycle interval is the reciprocal of the interpolated rate.
- No bore, stroke, mass, port area, valve geometry, air consumption, thermodynamics, impact energy, load or efficiency is modeled.
Historical Tappet and Valve Context
Hiscox includes a tappet valve for a rock drill among mining mechanisms. Historical patents show that rock drills used materially different arrangements: some mechanically moved valves through tappets and rods, while others used pressure passages to shift a distributing valve.
The illustration is therefore conceptual. It does not claim that all tappets, valves or rock drills share one porting sequence.
What This Explanatory Model Is Useful For
Use the calculator to perform two-point interpolation between entered rate anchors and convert the resulting rate to events per second and milliseconds per event.
Do not use it to select supply pressure, predict a drill's blow rate, size a compressor, set or repair a valve, estimate penetration, or approve equipment operation.
Entered Two-Point Interpolation
The two B values are independent user-entered anchors. The model imposes a straight line and extrapolates outside 80–100 psi. It contains no pneumatic derivation connecting pressure to frequency.
Worked Entered-Value Scenario
With entered anchors of 2,200 events/min at 80 psi and 2,800 events/min at 100 psi, the linear scenario returns 2,800/min at a pressure coordinate of 100 psi. That equals about 46.7 events/s and an implied 21.4 ms interval.
This restates the entered 100 psi anchor; it is not measured or predicted equipment performance.
Model Boundary
- Historical evidence: tappet-operated and fluid-distributing valve arrangements existed in rock drills.
- Calculated: straight-line interpolation or extrapolation between two entered anchors and reciprocal time conversions.
- Not calculated: actual cycle timing, valve motion, port flow, pressure losses, expansion, piston acceleration, impact energy, rebound, drill-steel behavior, air consumption, compressor demand, penetration rate, vibration, noise, wear or safe operation.
Frequently Asked Questions
Does pressure alone determine blow rate?
No. The model merely uses pressure as the coordinate between two entered rates.
Are the 80 and 100 psi rates manufacturer data?
No. They are user inputs.
What happens outside the two anchor pressures?
The same line is extrapolated, which may be physically unrealistic.
Does the animation run at the calculated rate?
No. It moves at an illustrative playback speed independent of the interpolated rate.
Can this size a compressor?
No. Air volume, pressure loss and duty cycle are absent.
Can it establish safe inlet pressure?
No. Follow the exact equipment documentation and qualified site procedures.
References
- Gardner D. Hiscox, Mechanical Movements, mining section: tappet valve for a rock drill.
- U.S. Patent 351,310, Rock Drill: tappet rod mechanically operating a valve.
- U.S. Patent 381,838, Rock Drill: tappets, rock shaft and valve arrangement.
- U.S. Patent 1,059,539, Rock Drill: pressure-fluid passages and distributing valve arrangement.
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