A Gordon job-printing press brings paper and an inked form together between a bed and a rocking platen. A cam-operated toggle advances the bed for the impression. Explore the opening and closing sequence here, then enter impressions per hour and ink-disc step to calculate cycle time and average disc rotation. These rate calculations do not determine impression force or a safe operating speed.
Gordon Printing Press Interactive Calculator
Enter press rate and ink-disc step to calculate cycle time and average disc rotation. The mechanism plays at a fixed illustrative speed.
Equation Used
This calculator converts the Gordon press impression rate into cycle timing and ink-disc indexing. IPH is impressions per hour and step_deg is the ratchet rotation of the ink disc each cycle. At 1,500 IPH and 30 deg per cycle, the disc turns 125 rev/hr, or about 2.08 rpm.
- One impression occurs per press cycle.
- The ink disc indexes once per cycle with no missed pawl steps.
- Press speed is steady over the calculation interval.
Bed, toggle and rocking platen
Gordon’s 1856 reissue patent describes a platen that rocks between sheet-receiving and impression positions. Once the platen is in position, a toe-cam acts on a toggle to advance the bed. The bed then withdraws, the platen returns, and the rollers ink the form for another impression.
The animation shows a simplified toggle and guided bed with a rocking platen. Its dimensions and timing are illustrative. It omits the complete cam profile, platen drive and roller mechanism, so it cannot establish contact pressure, dwell or collision clearance.
Read the cycle-rate results separately
Press Speed is the assumed number of impressions each hour. Disc Step is the entered angular advance of an ink disc per cycle. Neither input determines link dimensions or drive torque.
What the rate calculation is useful for
Use the results to convert an assumed production rate into seconds per cycle and average ink-disc speed. This is useful for comparing timing examples or documenting an existing setup.
The sheet rate assumes one successful impression on one sheet every cycle, with no interruptions or rejected sheets. Actual job completion time also includes setup, feeding, inspection, cleaning and stops. Entered values are examples, not rated capacities for a particular press.
Cycle and disc-rotation formulas
Let N be impressions per hour and θ the entered disc step in degrees per cycle.
- Sheets per minute = N / 60, assuming one sheet per impression.
- Cycle time = 3600 / N seconds.
- Average disc rpm = (N / 60) × (θ / 360).
- Disc revolutions per hour = N × θ / 360.
The disc rate is an average over complete cycles. A ratchet may advance during only part of each cycle; these formulas do not calculate its instantaneous speed.
Example: 1,500 impressions per hour
Enter 1,500 impressions per hour and a 30° disc step:
- Sheet rate: 1500 / 60 = 25 sheets/min.
- Cycle time: 3600 / 1500 = 2.40 seconds.
- Disc rotation: 1500 × 30 / 360 = 125 rev/hr.
- Average disc speed: 125 / 60 = 2.08 rpm.
Reducing the press rate to 1,000 impressions per hour gives 16.67 sheets/min, 3.60 seconds/cycle and 1.39 average disc rpm with the same step. Changing only the step to 15° halves the disc rate but leaves the sheet rate and cycle time unchanged.
What this does not tell you about a press
Printing quality depends on the form, paper, ink, packing, machine condition and actual contact force. Neither impression pressure nor required packing can be inferred from cycle rate. Use the instructions for the particular press when setting or maintaining it.
A closing platen is a crushing hazard. The throw-off changes whether an impression is taken; it should not be treated as a hand-protection device or an emergency stop. This animation provides no assessment of guarding or safe feeding time.
Frequently asked questions
Does Sheets / Min predict finished production?
It assumes one good sheet per impression and uninterrupted operation. Setup, rejected sheets and stops reduce actual production.
Why does the animation not speed up with Press Speed?
Playback uses a fixed seven-second illustrative cycle. Press Speed changes the numerical timing and average rotation results.
Why is Ink Disc RPM an average?
The entered angular step is spread over the full cycle for the rate calculation. A real ratchet advances intermittently.
Can this calculate impression force or paper pressure?
No. There are no force, form-area, packing, stiffness or torque inputs.
Does changing Disc Step alter printing rate?
No. It changes disc revolutions per cycle and average disc speed. Press Speed alone sets the assumed sheet rate.
Is the drawing suitable for setting cam timing?
No. The cam and complete linkages are not dimensioned or solved here. Use the correct machine documentation.
Can the throw-off protect a hand in the closing press?
Do not rely on it for that purpose. Impression control and operator protection are different functions; the drawing does not model either safety performance or stopping distance.
References and further reading
George P. Gordon, Improvement in Printing-Presses, reissue patent 366, 1856 — bed, toggle and rocking-platen arrangement.
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