Umbrella metal part
4-Fold Telescopic Shaft
Overview
- Made by
- Supply chain / partners
- Materials
- Carbon steel tube, electro-galvanised or chrome plated, Aluminium tube (lightweight version), Black epoxy or powder coating (design option)
- Finish options
- Chrome / nickel plating, Black epoxy or powder coat, Brushed aluminium, Matte anodised (aluminium version)
Selection tips
- Section count and wall thickness set the folded length together; a 1:3 reduction ratio is typical and has to be designed in, not discovered.
- All sections must be punched on the same generatrix or the push button will not line up after assembly. The drill jig matters more than the die.
- Aluminium reduces weight but cracks when swaged; where steel and aluminium touch, isolate the joint against galvanic corrosion.
- Telescoping feel comes from the sleeve and the clearance, not from opening up the tolerance.
Manufacturing process & quality control points
- 1
Tube cutting
Supply chain / partnersTube stock is cut to the length of each section. Cut squareness decides whether the sections butt cleanly when the umbrella is closed.
Quality control points
- Cut length and squareness · Caliper + squareness gauge per drawing · First article + 1 pc per 2 h
- 2
Swaging and end forming
Supply chain / partnersEach section is swaged so the next smaller section can telescope into it, and the ends are formed to take the tube latches. Swaging too deep locks the sections; too shallow and the frame racks when open.
Quality control points
- Swage depth and section fit · Go / no-go gauge on each joint · First article + 1 pc per 2 h
- Latch seat position · Fixture check per drawing · First article + 1 pc per 2 h
- 3
Hole punching
Supply chain / partnersHoles for the latch, the runner stop and the rivets are punched. Burrs inside the tube from punching are a classic cause of a section that will not slide.
Quality control points
- Hole position and burr · Fixture + visual, no burr inside the tube · First article + 1 pc per 2 h
- 4
Deburring and pre-treatment
Supply chain / partnersSections are deburred and cleaned before finishing. Any swarf left inside the tube ends up jamming the telescoping action.
Quality control points
- Internal cleanliness · Blow-out and visual check · 100%
- 5
Surface finishing
Supply chain / partnersPlating or coating is applied by the supply chain. On a telescopic shaft the coating adds thickness inside the bore as well, so the swage tolerance has to allow for it.
Quality control points
- Coating thickness · Thickness gauge per buyer spec · Per batch
- Corrosion resistance · Neutral salt spray, 5% NaCl, 35 C (ISO 9227 / GB/T 10125) · Per batch
- 6
Straightness and telescoping check
Supply chain / partnersFour sections means three joints; each one adds a racking point, so latch engagement length is checked section by section. The shaft is checked straight and cycled through full extension and retraction. A section that binds when dry will bind worse once the frame is loaded.
Quality control points
- Straightness · Roll on a flat plate, no visible wobble · First article + 1 pc per 2 h
- Telescoping smoothness · Manual extend / retract x10 per shaft · 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 4-Fold Telescopic Shaft
Custom materials, finishes and logos available. Send your drawing or sample.