Search “sofa bed hinge types” and you’ll hit a list of names — butterfly, spring, piano, knuckle, continuous — that sound like a hardware catalog but rarely match what a factory actually stocks. Here’s what those names mean, and then the honest part: which ones we make and which we match by sample.
The type names buyers use
- Spring hinge — has a return spring; the classic sofa-bed hinge that helps the bed section swing and settle. This is the one we make most.
- Butterfly hinge — leaf shape like a butterfly; common on lighter folding furniture.
- Piano (continuous) hinge — one long hinge running the full length of the joint.
- Knuckle hinge — the standard pinned butt hinge, named for the knuckles.
- What people call a “ratchet sofa bed hinge” — that’s usually a different family (our ratchet range), not a sofa-bed hinge proper.
The names describe a shape or action. They don’t tell you the dimensions, the spring force, or whether it fits your frame. So treat them as a starting point, not a spec.
What we actually make (catalog-verified)
Our Sofa Hinges range is iron, galvanization or black finish, and it splits into three groups:
Pull-out sofa bed mechanisms
- 301 — Pull out sofa bed mechanism (dual wheel)
- 302 — Pull out sofa bed mechanism (single wheel)
- 303 — Pull out sofa bed mechanism (drawer)
Sofa bed hinge & plate
Sofa bed spring hinges
- 306 — Sofa Bed Spring Hinge (small)
- 307 — Sofa Bed Spring Hinge (medium)
- 309 — Sofa Bed Spring Hinge (split spring)
So when a buyer says “spring hinge,” Models 306, 307 and 309 are the ones. When they say “pull-out mechanism,” that’s 301–303. The “large,” “small,” “medium” words are part of the official names — they’re not full dimensions, so confirm the actual size before you order.
Picking the right type
Start from your frame, not the name:
- Is it a pull-out bed (301–303) or a hinged fold (304–309)?
- Does it need a return spring (306/307/309)?
- Confirm length, thickness, mounting geometry from a drawing or the original part.
A photo alone often isn’t enough — similar-looking hinges can have different mounting. Send a few angles plus the key dimensions.
FAQ
What are the main sofa bed hinge types?
Buyers name them butterfly, spring, piano, knuckle, continuous. We make pull-out mechanisms, a sofa bed hinge, a hinge plate and spring hinges — the spring type (306/307/309) is our most common.
Is a spring hinge the same as a pull-out mechanism?
No. A pull-out mechanism (301–303) is a different hardware system from a spring hinge (306/307/309). Confirm which your sofa uses.
Do you make piano or knuckle hinges?
Those are market type names. If your frame needs that shape, send a sample or drawing and we’ll confirm whether a catalog model matches or we make it to spec.
How do I know which model fits?
Match the function (pull-out vs hinge vs spring), then confirm dimensions and mounting from the product page or a sample. Don’t pick by the name alone.
For the pull-out-vs-hinge decision in detail, the sofa bed mechanism types guide breaks it down. For volume or OEM, the sofa bed hinge manufacturer page covers supply.
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