A quick coupler (quick hitch) is the locking device between the excavator dipper and the attachment. It lets an operator change buckets, rakes and grabs without leaving the cab or touching pins by hand. The coupler is also the single most common source of mismatched attachments: a bucket built for one hitch standard will not lock into a machine built for another. This guide explains the interface codes used across KaiVoy attachments – S30-180, S40 and S45 – and how adapters bridge different standards.
The three KaiVoy interfaces at a glance
| Interface | Typical machine class | Common attachments on this interface |
|---|---|---|
| S30-180 | 1.0 – 1.8 t mini excavators | Cable laying buckets, 430 mm digging buckets, 800 mm grading buckets, ripper / scarifier |
| S40 | 3.5 – 5 t excavators | 620 – 720 mm digging buckets, 1200 – 1300 mm grading buckets, stone gripper |
| S45 | 8 t excavators | 800 mm digging bucket, 1400 mm grading bucket, 400 mm cable laying bucket |
The codes follow the attachment, not the machine: when you order a KaiVoy bucket you choose the coupler code your machine runs. If you are unsure which code fits, send us the machine model and we confirm the interface before production.
Coupler types you will meet
- Manual wedge couplers – the pin or wedge is seated by hand or with a hammer. Simple and cheap, found on most mini excavators. Slowest to swap, but few parts to fail.
- Hydraulic pin-pull / wedge couplers – a hydraulic cylinder actuates the lock from the cab. Standard on 3.5 t and larger machines and required for fast attachment cycling.
- Tilt couplers – add a hydraulic tilt axis between dipper and attachment so the bucket angles left and right for slope trimming and ditch work. See our TS30 tilt coupler (110 mm).
- Adapter plates – not couplers themselves, but plates that let an attachment built for one standard run on a machine with another. We supply three: AD-602-BIG BM, AD-602-SSH1140 and AD-EURO-S1140.
How to choose
- Match the interface code first – geometry, pin diameter and lock style must all agree.
- Count your hydraulic circuits. A tilt coupler needs one auxiliary circuit for the tilt function.
- Weigh the penalty. Every coupler adds weight and length to the dipper end, which costs breakout force. On 1 t machines this is noticeable; keep the coupler light.
- If you run attachments from mixed suppliers, an adapter plate is usually cheaper than re-pinning every attachment.
Full dimensions for every attachment and interface are listed on our machinery attachments specifications page. For a quote, contact KaiVoy with your machine model and the attachments you need.