Drive shafts(updated 2026-03-20) — yoke track side/top views, pull bracket + rod stopper, top cap concept (figures).
Introduction
The transmission converts the drivetrain's rotary cam motion into a controlled linear stroke that drives the extraction and core ejection cycle. A scotch-yoke assembly rides on two 35 mm hardened stainless shafts guided by flanged linear bearings (LMK35UU family), carrying force from the drivetrain cam bearings through to the extraction and synchronisation module where fruit is pressed against the collection peelers. The assembly mounts on a dedicated transmission mount plate bolted to the main frame.
Colour key & components
Applies to the figures on this page.
Colour(s)
Component
Yoke — interfaces with drivetrain cam bearings and converts rotation into the extraction stroke.
Two drive shafts (35 mm) — linear guides for the yoke; shaft mounts at both ends set parallelism and stiffness.
Two LMK35UU linear bearings — support low-friction yoke translation on 35 mm shafts; alignment prevents binding.
Transmission mount plate — mounts to frame; carries shaft mounts and maintains shaft spacing/alignment.
Figures
CAD views. Refer to figures in the text as Figure 1, Figure 2, etc.
Figure 1. Transmission assembly: mount plate, yoke, two shafts, two LMK35UU linear bearings.
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Discussion
Rough design & intent
Purpose — Convert drivetrain cam-roller motion into a controlled linear stroke while maintaining alignment between extraction and collection peelers. Transmission stiffness and repeatability are critical to prevent binding and collisions.
Key elements — Yoke, two 35 mm shafts, flanged/sealed 35 mm linear bearings (LMF/LMK family), and transmission mount plate. Shaft length is driven by the distance between collection-side peelers and the required "almost-touch" gap at end of compression stroke (target ~2–3 mm gap between driven and static peeler faces at end-of-stroke).
Maintenance reality — Expect full teardown/reassembly roughly seasonally (≈ yearly). Alignment strategy must support repeatable rebuild without full re-machining.
Known issues & risks
Jam / asymmetric binding case — Worst case is one linear bearing binding or fruit/junk causing asymmetric loading. Shafts can twist and impose large moments into linear bearings and the mount plate; system should survive a high factor-of-safety "rock in juicer" scenario.
Moment amplification — Linear bearings are elevated off the mount plate. Vertical offset creates overturning moments that try to rotate the mount plate; the frame/dowels/bolts must carry these without shifting.
Washdown exposure — Transmission mount plate front face is exposed to cleaning spray/juice; materials, seals, and scraper/guards matter.
DFM & manufacturing (China)
Alignment workflow — Expect an "align → tighten → drill/ream for dowels" workflow similar to frame/drivetrain plates. Contractor should propose the exact datum scheme and repeatable shim strategy.
Two plate architectures — Transmission mount plate has two candidate designs: (a) sand-cast + post-machined, and (b) welded steel plate + stress relief + machining. Contractor to advise best cost/lead/quality path.
Hygiene surfaces — Any surfaces near pulp/juice should have cleanable finishes and avoid crevices; consider scraper/cover designs for shafts and bearing faces.
Optimizations sought
Binding robustness — Maximize tolerance to misalignment and contamination without shaft galling or bearing failure.
Repeatable alignment — Fast seasonal rebuild that returns peeler alignment without extensive re-shimming.
Cleanability — Reduce juice accumulation on shafts/bearings; add scrapers/covers where needed.
Questions for contractor
Define load cases for the transmission, including an asymmetric/jam case (one side binds) and a "hard object" worst case. Provide force/moment estimates into the mount plate and frame.
Recommend an alignment + dowelization procedure for seasonal teardown/rebuild (what is adjustable, what gets reamed for dowels, and what is shimmed).
Recommend acceptable shaft parallelism and bearing alignment tolerances to prevent binding over service life, and propose inspection checks.
Propose a shaft scraper/cover approach for washdown, including materials compatible with cleaning chemicals and expected wear/maintenance intervals.
Recommended figures (contractor clarity)
Add figure: Free-body — yoke + shafts + linear bearings showing jam/asymmetric load case and moment arms into the plate.
Add figure: Datums — sketch of which faces/holes define peeler alignment and which interfaces get doweled after alignment.
Add figure: Scraper concept — sectional sketch of the proposed formed-sheet cover + scraper lip on shaft.
