A combined tire-upsetting and punching machine can shorten a local section of a metal wheel tire and can also drive a punch using the same moving jaw. The calculator models the resulting thickness change under a simple constant-volume, constant-width assumption. The animation distinguishes permanent upsetting of the workpiece from the return of the released jaw.
Combined Tire Upsetting and Punching Machine Interactive Calculator
Change the free length between grips, jaw advance and starting thickness to explore ideal local upsetting of a metal wheel tire. The jaw returns after releasing its grip while the modeled thickening remains. A second aligned view shows the punch attached to the same moving carriage.
Equation Used
- A straight local segment represents part of a metal wheel tire.
- The loaded free length shortens by the entered jaw advance; the gripped portions retain their initial thickness.
- Volume and width stay constant; all shortening produces uniform thickness increase.
- The formed material stays shortened when the moving grip releases and the carriage returns.
- Punch is shown attached to the moving carriage, with its die unloaded.
- Animation cycle time is illustrative; no forming force, heating schedule or material failure limit is calculated.
Local metal-tire segment, not a pneumatic tire. Ideal uniform thickening assumes unchanged width and volume. The drive transmission is omitted; jaw and attached punch share the same translation. No force, temperature or forming-limit recommendation.
Gripping, shortening and returning
Hiscox figures 1369 and 1370 describe cam jaws that grip the tire, a sector-cam lever and pinion that advance the movable jaw, and a punch attached to that jaw with its die in the machine’s horn. The upsetting jaw and punch therefore share one carriage motion.
The upper view shows the local strip between fixed and moving grips. Both hold during the advancing stroke. The free segment becomes shorter and, in the calculator’s idealization, uniformly thicker. The moving grip then opens and its carriage returns. The stock remains attached at the fixed grip and does not spring back to its original thickness. Fresh stock is implied at the start of the next demonstration.
The lower aligned view follows the same carriage displacement. Its punch advances toward the fixed horn die and returns with the jaw. The die is shown empty: this is an explanation of the shared motion, not a simultaneous punching-load calculation. The hand-drive transmission is omitted, so its gear and cam geometry should not be inferred from the drawing.
A local metal-tire model
The word tire here refers to the metal band around a wheel, not a modern pneumatic tire. Upsetting can shorten a section without removing its material. This page isolates a straight local segment so the relationship between shortening and thickening can be inspected.
The model is useful for comparing ideal geometry. It does not establish how to heat, grip or form a particular historic tire, nor whether a given amount of shortening can be achieved without damage.
Constant volume and unchanged width
Let the initial free length be L₀, starting thickness be t₀ and width be w. If the jaw advances by s, the final free length is L₁ = L₀−s. Conserving volume gives L₀t₀w = L₁t₁w. With the same width before and after, t₁ = t₀L₀/(L₀−s).
The thickness increase is t₁−t₀, and the percentage gain is 100(t₁/t₀−1). The animation uses the same equation throughout the advancing stroke. During the return it holds the final material geometry while the released jaw moves away.
Uniform deformation and no side spread are strong assumptions. Real material can barrel, spread laterally or deform unevenly. The equation calculates an ideal geometric result; it is not a forming-force or material-failure model.
Worked ideal-upsetting example
For 75 mm of free length, 6 mm starting thickness and 10 mm jaw advance, the final length is 65 mm. The ideal final thickness is 6 × 75 / 65 = 6.923 mm. The increase is 0.923 mm, or 15.38%.
The initial length-thickness product is 450 mm² per unit width. The final product is also 65 × 6.923 = 450 mm² to rounding. Doubling the starting thickness doubles both the final thickness and absolute gain, but leaves the percentage increase unchanged.
Changing the animation cycle from 6 seconds to 12 seconds slows the displayed motion by a factor of two. It does not alter the calculated final length or thickness.
Model limits
A larger selected shortening gives a larger ideal thickness increase. The permitted slider range is for comparison and does not define a safe forming limit. The calculation does not include flow stress, temperature, grip slip, width spread, buckling or cracking.
The punch is a second function of the same moving carriage. Its required force and die dimensions would need their own material and tooling inputs; they are not inferred from the upsetting geometry.
Tire-upsetting questions
Why does the material stay thick when the jaw returns?
The model represents permanent forming. The moving grip releases before the return stroke, so returning the carriage does not reverse the shortening of the workpiece.
Does the width increase?
Not in this calculation. It deliberately holds width constant, which makes the thickness result simple to compare. Actual material may spread sideways or barrel.
Does cycle time change the thickness result?
No. It controls playback speed. Final geometry depends on initial free length, jaw advance and starting thickness.
Why does the punch move with the jaw?
The historical description attaches the punch to the moving jaw and puts the die in the machine’s horn. The second view makes that shared displacement visible.
Can the result be used as a heating or force specification?
No. The calculator has no temperature, material-strength or tooling model. It gives only an ideal geometric thickening under the stated assumptions.
Historical reference
Gardner D. Hiscox, Mechanical Movements, Powers, Devices and Appliances, printed page 332, figures 1369–1370. The top and sectional views show the cam grips, shared moving jaw and punch, and fixed horn die. The animation explains their motion with illustrative proportions rather than construction dimensions.
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