Umbrella metal part
Reverse-Folding Rib
Overview
- Made by
- Supply chain / partners
- Materials
- Carbon steel strip (U-channel), Fibreglass (FRP) tail, Steel hinge pin with inverted pivot
- Finish options
- Zinc / nickel plating, Black epoxy, Matte powder coat
Selection tips
- The pivot direction is inverted, so the tooling cannot be shared with a standard rib: confirm the fold direction before cutting steel.
- An inverted structure is less forgiving on length: a 1 mm error and the umbrella will not close.
- The wet side ends up inside when closed, so specify stainless rivets and a finish that tolerates water.
- Against a standard rib: the selling point is clear but cost and assembly scrap are higher, so leave margin in the quote.
Manufacturing process & quality control points
- 1
Blanking and forming
Supply chain / partnersRib stock is blanked and the U-channel is formed. On a reverse frame the pivot sits on the opposite side of the rib compared with a conventional frame, so the forming tool is dedicated, not shared.
Quality control points
- Length and channel geometry · Caliper / profile gauge per drawing · First article + 1 pc per 2 h
- 2
Inverted pivot hole punching
Supply chain / partnersHinge holes are punched on the inverted pivot line. Getting this hole on the wrong side is the classic reverse-frame manufacturing error: the umbrella then folds the conventional way and the whole selling point is lost.
Quality control points
- Pivot side and hole pitch · Fixture check with a left/right-proof jig, no mis-punch · 100%
- 3
Surface finishing
Supply chain / partnersPlating or coating is applied by the supply chain and checked for thickness and corrosion.
Quality control points
- Coating thickness · Thickness gauge per buyer spec · Per batch
- 4
Fold direction check
Supply chain / partnersEvery rib is folded through its full travel to confirm it inverts the correct way. This is checked on the rib before it is built into a frame, because the error cannot be corrected later.
Quality control points
- Inversion direction · Manual fold-through on each rib against a master rib · 100%
Used in
Relevant compliance
- EU REACH (SVHC)
EU
All metal & plastic parts, electroplated components and fabric coatings
- California Proposition 65
US
All products sold into California containing listed chemicals
Get a quote for Reverse-Folding Rib
Custom materials, finishes and logos available. Send your drawing or sample.