Pain2HuStle · ReCoil · Austin Little's design
The whole invention is one CNC piece — the barrel drive ring. Clamp it on the existing barrel, and a handy garage crew bolts up the rest with standard end bearings, tube, commercial springs, drums, cables, pulleys, hoist and motor. Reference door: 12 ft × 12 ft, 432 lb curtain, 2,592 in-lb peak.
A split, serrated steel ring whose bore is machined to the barrel OD (a size family: 6″/8″/10″/12″…). It wraps the rotating barrel end — past the curtain edge — and bolts together in the field without unsheeting the curtain. Its outer face carries the drum/sprocket. This is what grabs the door; nothing off-the-shelf does it.
Grab the part that SPINS: the center shaft is fixed — the barrel pipe rotates. The ring clamps the barrel (or its rotating end plug), never the dead shaft.
The cable pays ~1.2″ sideways across the drum over the door's travel. If the lead pulley/2nd-drum sits too close, the cable leaves the groove at too steep an angle and climbs out / jams. Simulated max fleet angle vs. pulley standoff (3/16″ cable, N=1.5):
| Pulley standoff | Max fleet angle | Verdict |
|---|---|---|
| 6″ | 5.7° | JAMS — climbs out |
| 8″ | 4.3° | jams |
| 10–17″ | 3.4° → 2.0° | marginal (smooth/lagged only) |
| 20″ | 1.7° | CLEAN (grooved) |
| 25–30″ | 1.4° → 1.1° | clean |
Rule baked into the bracket: mount the pulley/2nd-drum ≥18″ from the drum (aim 20–24″), groove plane aligned to the center of the wrap zone. Never under ~9″. Design lever: a bigger drum reels the cable in fewer turns → less sideways travel → shorter safe standoff. And the end bearing plates are the alignment reference — cock a drum axis even ~0.5° and it eats your fleet budget, so square is a CNC tolerance, not bolt-and-hope.
Favor this load path: split barrel drive ring on the rotating barrel/end plug -> keyed sprocket or keyed drum -> guarded chain/cable path -> upper torsion tube -> ganged stocked springs -> jackshaft/hoist on the same service side. The dead center shaft is not the drive point.
Pulley/block option: the reference-board pulley rig is modeled as a heavy commercial stationary/floating sheave set on punch-angle standoffs. Residential extension-spring pulleys show the shape only; the real design needs commercial WLL above the calculated coupling pull plus safety factor.
Operator/hoist rule: manual hand-chain stays visible and reachable on the jamb. An 8500-style operator is prototype/off-label for rolling steel; route its emergency release to the same side with guides/hooks, and validate cable monitoring on the bench. A commercial jackshaft is the cleaner product path.
| # | Part | Size / spec (ref. door) | Source | Function |
|---|---|---|---|---|
| 01 | Barrel drive ring ◆ | split · bore = barrel OD (6/8/10/12″) · serrated · 4× 3/8 Gr8 + pins · 2,592 in-lb · 1/2–3/4″ steel | CNC | The invention. Clamps the spinning barrel, carries the drum, no curtain removal |
| 02 | Master mounting bracket | 1/2–3/4″ steel, gusseted · holds tube brg + anchor + motor + pulley · pulley standoff ≥18″ | CNC | One plate holds it all → install is a bolt-up. Adjustable standoff = fits a range (your S1 slice) |
| 03 | Cable drum(s) | commercial high-lift grooved (400-series) · groove cap ≥ 3.8 turns × N | stock | Reels the coupling cable; grooved = self-guides (the drum IS the install variable) |
| 04 | Lead pulley / fairlead | ≥18″ from drum, aligned to wrap center | stock | Routes the cable so fleet angle stays ≤2° (no jam) |
| 05 | Aircraft cable | 3/16″+ · tension = torque ÷ drum radius | stock | The coupling (drum-to-drum = ratio-stable, no drift) |
| 06 | Counterbalance tube + cones | 1–1.25″ shaft · std winding + stationary cones | stock | Carries springs, drum, motor, hoist — one shaft |
| 07 | Torsion springs (×2 ganged) | commercial 2.625–3.75″ ID · .375–.4375″ wire · ~20–30″ ea · NOT resi 1.75/2″ | stock | The counterbalance. Broken one = ladder swap |
| 08 | End bearing plates (×2) | std · held SQUARE ±0.5° (alignment reference) | stock | Hold tube + drums true so cables track |
| 09 | Jackshaft operator (motor) | commercial jackshaft (or 8500 + S2 adapter) | stock | Daily power op, side-mounted |
| 10 | Manual chain hoist | ~4:1 reduction · hand-chain down the jamb | stock | Emergency lift (springs do most of it) |
| 11 | Emergency release | floor-reach disconnect (or routed 8500 cord) | stock | Declutch motor from the floor (UL 325) |
| 12 | Drop-safety / governor | centrifugal brake on the barrel | MANDATORY | Catches a runaway if spring/cable/ring fails — PE item |
Cycle life is the ratio's job. At 1:1 the springs wind only ~3.8 turns to make all the torque → high stress → low cycle (~10k). Geared at N≈1.5–2 they wind 5.7–7.6 turns → lower stress → 25k–50k cycles with commercial springs. The spring house tables the exact wire/coils/cycle from torque + turns + target.
Patent (from the read): the retrofit method (leave the dead spring sealed, curtain stays sheeted) is open (S3); the drive ring is your strongest apparatus claim — nothing found touches it. Keep spring tensioning conventional-cone (dodges the one expired blocker), and file before any public pitch.