[family-assembly] light_duty_swivel_plate_caster: JW Winco EN 22870 Form L

[sunzhenchuan007]

Family

• Family: light_duty_swivel_plate_caster — multi-body assembly
• Standard: JW Winco EN 22870, unbraked Form L light version
• Closes [family-assembly] light_duty_swivel_plate_caster #58

Reference — issue #58

Official engineering drawing	Form L product photo

The official metric dimension table and the complete source/evidence discussion
are preserved in #58.

Generated — easy / medium / hard grid

Generated — four benchmark views

Extremes — 40 mm and 80 mm catalog rows

Components and assembly

Each panel highlights one named physical component while preserving the full
assembled context.

How it is parameterized

catalog_size selects one complete official Form L row. refine() copies all
nine associated catalog dimensions together, so dimensions from different
sizes cannot be mixed.

catalog_size	wheel Ø	wheel width	axle Ø	overall height	plate L × W	swivel offset	mount pitch X × Y
40	40	18	5	59	42 × 42	24	30 × 33
50	50	18	6	66	55 × 55	21	38.5 × 44
60	60	24	6	83	60 × 60	21	38.5 × 48
80	80	24	6	104	60 × 60	30	38.5 × 48

Difficulty separation:

• easy: real 50 and 60 mm rows; unpublished details fixed at baseline proportions
• medium: real 40, 50, and 60 mm rows; small proportion-only variation
• hard: all four real rows, including 40 and 80 mm extremes; wider but valid proportion-only variation

The family has 13 parameters: one sampled row selector, nine row-coupled
official dimensions, and three bounded proportion scales for unpublished
sheet, race, and slot details.

Multi-body assembly

build() returns a deterministic cq.Assembly with four stable children that
match family.json.components and "solids": 4:

1. mounting_plate — plate and simplified upper swivel-race envelope
2. swivel_fork — fork, bridge, and simplified lower race
3. wheel — connected rubber-tread / polypropylene-core wheel envelope
4. axle_fastener — simplified connected axle, head, and nut envelope

The real caster swivels and the wheel rotates, but this benchmark intentionally
represents one static assembled reference pose.

Verification

bench2 validate light_duty_swivel_plate_caster → PASS

• 13 complete parameters
• easy / medium / hard: 4/4 seeds sample, check, build, and execute clean
• all four official catalog rows covered
• difficulties produce distinct programs
• 10/12 unique sampled shapes
• every sampled instance contains exactly four non-degenerate solids
• Ruff passes for part.py and spec.py

Component-level audit for all four catalog rows:

Catalog row	Maximum pairwise intersection	Minimum component clearance
40	0 mm³	0.20 mm
50	0 mm³	0.20 mm
60	0 mm³	0.20 mm
80	0 mm³	0.20 mm

All standard previews and preview_parts.png were regenerated and inspected.
The committed previews use the projected-center camera framing documented in
#68; that renderer-only correction changes neither family geometry nor sampled
programs.

Checklist

• bench2 validate light_duty_swivel_plate_caster passes locally
• preview.png, preview_views.png, preview_extremes.png, and preview_parts.png are committed and inspected
• family.json declares four named components and "solids": 4
• official dimensions are selected as complete catalog rows, never freely combined
• every unsupported construction dimension is documented as proportion or deliberately omitted
• PR touches only designs/light_duty_swivel_plate_caster/
• commit is DCO-signed
• AI-assisted; I reviewed the implementation and engineering constraints

Sources and scope

• JW Winco EN 22870 product page
• JW Winco EN 22870 metric dimension PDF
• official engineering drawing and Form L product photograph in [family-assembly] light_duty_swivel_plate_caster #58
• documented proportion formulas for unpublished plate/fork thicknesses,
  race envelopes, slots, wheel profile, bends, and fastener details

Scope is strictly unbraked Form L order codes
EN 22870-{40|50|60|80}-G-L-L-ST. Rigid, braked, center-hole, and
threaded-stud forms are excluded. Hidden bearings, threads, washers, lettering,
materials, load analysis, and motion simulation are deliberately omitted.

NOTES.md documents catalog-symbol mapping, all proportion formulas,
engineering constraints, component boundaries, clearances, and deliberate
deviations.

[github-actions]

Welcome, and thanks for the family PR! Three things that answer most questions:

• No checks running? A maintainer must click Approve workflows once for your first PR — pending, not ignored.
• Red gate? The message tells you the fix: click Details, or read the bench2 validate report comment posted after each run. Reproduce locally with uv sync && uv run bench2 validate <family> (debug help).
• Scope: designs/<family>/ holds only the package files (reference drawings/photos go in the family issue), and the PR checklist must be fully ticked. Not done yet? Mark the PR as a Draft.

中文:红 ✗ 点 Details 或看 validate 报告评论;本地 uv run bench2 validate <family> 复现;参考图放 issue 不放 PR;没做完用 Draft。入门 → GETTING_STARTED.zh

[github-actions]

bench2 validate

light_duty_swivel_plate_caster

  ✓ family.json: keys + base_plane valid
  ✓ pieces: build(13 params) + PARAM_SPEC + check present
  ✓ PARAM_SPEC: 13 params, all entries complete
  ✓ easy: 4/4 seeds sample+check+build+execute clean
  ✓ medium: 4/4 seeds sample+check+build+execute clean
  ✓ hard: 4/4 seeds sample+check+build+execute clean
  ✓ coverage: catalog_size reaches all 4 declared values (standard table fully covered)
  ✓ difficulty separation: difficulties produce distinct programs
  ✓ geometry novelty: 10/12 unique shapes (17% duplicate)
  ✓ solids: every instance non-degenerate, 4 solid(s) each (declares solids=4)
PASS — designs/light_duty_swivel_plate_caster

Previews: the previews artifact on this run.