Indexed conveyor changeover
Parametric CAD reference for three carton widths with overhead sliding carriages, indexed positions and independent captive clamps.
Completed commissioning study
30 N maximum reference static side load per guide, 3 N m M 8 clamp torque, friction>=0.10, specified unworn tolerances. Loaded worst-case side clearance 0.744 mm against a 0.25 mm allocation; all four indicators must match the requested width.
Executed synthetic/theoretical results, rejected cases and acceptance matrix. Source: complete_validation.py.
Reference dimensions
| width_mm | rail_center_mm | nominal_opening_mm | minimum_side_clearance_mm | minimum_overhead_plate_clearance_mm | shaft_travel_margin_mm |
|---|---|---|---|---|---|
| 80 | 48.0 | 84 | 1.03 | 8 | 112.0 |
| 120 | 68.0 | 124 | 1.03 | 8 | 92.0 |
| 180 | 98.0 | 184 | 1.03 | 8 | 62.0 |
Mechanism
- Two overhead 20 mm shafts carry independently sliding guide assemblies. The product envelope stays below the overhead mechanism.
- Four plungers locate the two guides at both support stations; four separate slotted clamps hold the setting.
- A 2 mm floating shoe fills the carriage-to-index-plate gap at the clamp. The clamp washer is wider than its continuous slot.
- UHMW strips are replaceable without changing the indexed support positions.
Verification
- 14 geometry and interval checks passed. STEP and STL assemblies exist for all three widths.
- The carton swept volume was intersected with each non-belt solid. Continuous motion checks use monotone interval boundaries plus a 101-position record.
- Worst-case per-side running clearance is 1.03 mm after the declared tolerance and carton-size allowances.
- Intentional joints and overlaps are not a strength or complete assembly-interference certification.
Changeover procedure
- Stop and isolate conveyor motion under the site procedure; remove cartons from the adjustment zone.
- Loosen four captive clamp knobs; lift four index plungers clear of the plates.
- Move each rail at both supports until the selected 80, 120 or 180 label is visible and each plunger is fully seated.
- Tighten clamps to the validated setting. Confirm both stations and both sides indicate the same width.
- Pass a reference carton through by hand with motion isolated. Check wear strips, fixings and minimum clearance before restart.
Physical trial sheet
- For each carton width, perform 10 returns from wider settings and 10 from narrower settings, using two operators.
- Record left/right rail position at both stations, approach direction, clamp setting, carton clearance and elapsed changeover time separately.
- Measure after a defined wear cycle and after cleaning. Compare the actual distribution with the worst-case budget.
- Check plunger engagement, retained hardware, pinch points and abnormal carton jams before releasing the mechanism.
Bill of materials
| item | quantity | material | size | note |
|---|---|---|---|---|
| Guide rail | 2 | 304 stainless | 500 x 30 x 6 mm | Replaceable UHMW strip on carton face |
| Wear strip | 2 | UHMW-PE | 500 x 30 x 3 mm | Three M4 flush fixings; inspect retention |
| Cross shaft | 2 | Ground stainless | 20 diameter x 400 mm | Sliding fit; no load qualification |
| Carriage | 4 | 6061 aluminum | 90 x 30 x 32 mm | 20.20 bore; dry polymer sleeve or alternative bearing requires fit revision |
| Index plate | 2 | 304 stainless | 80 x 400 x 7 mm | Six 8.15 holes; 350 x 9 clamp slot |
| Index plunger | 4 | Purchased stainless | 8 mm pin envelope | Specify lift travel >=10 mm and positive captive retention |
| Clamp screw/knob | 4 | Purchased stainless | M8 envelope | 18 mm captive washer; thread and retention to supplier detail |
| Clamp shoe | 4 | Stainless | 18 x 24 x 2 mm | Transfers clamp load without moving shaft center |
| Hanging strap | 4 | 304 stainless | 25 x 42 x 6 mm | Welded or bolted joint to be sized for application |
| Frame post | 4 | Reference frame | 90 x 20 x 165 mm | Envelope, requires attachment design |
Limits
- This is a dimensioned reference conveyor interface, not a measured retrofit to an existing line.
- CAD checks cover nominal product clearance, sliding envelopes and validity; clamp force, shaft deflection, joints, fatigue and impact loads are not qualified.
- Plungers, knobs and threaded hardware are envelopes. Select supplier parts and finalize their retention, threads and lift travel before manufacture.
- No physical changeover time, repeatability, sanitation certification or wear life is claimed.
- The mechanism has independent guides and can be set incorrectly. Both stations and both sides must show the same carton label before restart.
- Reference drawings are not a manufacturing release. Frame attachment, guarding and lockout procedures require the intended machine assessment.
CAD library reference
CadQuery import and export documentation. Each assembly is reimported from STEP and its volume compared with the source solid.
Reference design by CJ Ackley. Numerical and geometry checks are not a physical qualification.