In the exact Scotch-yoke reference used here, one shaft revolution produces one complete out-and-back reciprocation cycle. Peak-to-peak ram travel is 2r, cycle time is 60/N, and the displacement from TDC at angular stop error α is r(1 − cos α).
Actuator motion note for Single Revolution Per Stroke Mechanism
For single revolution per stroke mechanism, a linear actuator can be used when the design needs controlled push-pull motion instead of continuous rotary input. The first check is whether the required stroke, speed, and end positions match the mechanism geometry.
For structural members, the actuator load should be applied through brackets that do not introduce unintended bending. Check both static load and the extra load created when the mechanism starts, stops, or binds.
The clean way to review it is to sketch the linkage at the start, middle, and end of travel. At each position, check the line of action, required force, available clearance, and whether the actuator rod remains close to axial loading.
- Map actuator stroke to the actual output travel before choosing a model.
- Check for binding, changing leverage, and peak load near the ends of travel.
- Decide whether timed motion is acceptable or position feedback is required.
For a FIRGELLI design review, calculate the load case with the FIRGELLI actuator force calculator and plan the switching or controller arrangement with the linear actuator wiring diagram generator. If an actuator or cylinder is already installed, the linear actuator replacement finder helps keep the comparison tied to real dimensions.
One Revolution per Reciprocation Cycle · Scotch-Yoke Reference
Explore exact Scotch-yoke travel, cycle rate and near-TDC geometric offset for one revolution per complete reciprocation.
Equation Used
- The crank pin runs without clearance in an ideal transverse yoke slot.
- The ram translates on a straight guide.
- One shaft revolution produces one complete reciprocation cycle.
- Stopping dynamics, loads, friction, wear and structural limits are excluded.
One reciprocation cycle means the complete out-and-back motion; it contains two directional strokes.
Crank pin, transverse slot and guided ram
A finite crank pin runs in the yoke's vertical slot while the complete yoke and ram translate horizontally. The closed geometry produces exact simple harmonic ram motion without a finite connecting rod.
What the calculator determines
Select crank radius, shaft speed and angular stop error from TDC. The calculator reports peak-to-peak travel, one-revolution cycle time, reciprocation cycles per minute and the exact Scotch-yoke displacement from TDC at that angular error.
Exact Scotch-yoke identities
Travel = 2r; cycle time = 60/N; cycles/min = N; TDC offset = r(1 − cos α).
Selected-input arithmetic
At r = 25 mm and N = 300 rpm, peak-to-peak travel is 50 mm and cycle time is 0.2 s. A 5° stop error gives about 0.095 mm displacement from TDC.
Kinematic reference only
The model excludes clearance, pin and slot dimensions in the arithmetic, contact stress, impact, friction, lubrication, inertia, drive torque, structural strength, controls and stopping dynamics.
Questions
Is a cycle one directional stroke?
No. Here one cycle is the complete out-and-back reciprocation generated by one revolution.
Does angular accuracy guarantee stopping accuracy?
No. The formula maps a selected angular error to ideal geometric displacement only.
References & Further Reading
- Wikipedia contributors. Punch press. Wikipedia
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