What is a quick coupler?
A quick hitch — also called a quick coupler, quick release, or hitch coupler — is a mechanical interface that connects to the end of your excavator's dipper arm. Its purpose is straightforward: it lets you swap attachments quickly without stopping work to manually repin.
Without a quick hitch, changing from a digging bucket to a hydraulic breaker typically requires an operator to leave the cab, manually remove the two dipper pins that hold the attachment, fit the new tool, and repin it. On a busy site, this can take 20 minutes or more per change. A quality quick hitch can reduce that to under two minutes.
The productivity argument for quick hitches is clear. But safety is equally important: a poorly designed or maintained coupler can allow an attachment to fall without warning, with potentially fatal consequences. That is why the UK Health and Safety Executive has issued specific guidance on quick hitch safety, and why choosing a reputable, compliant product matters.
Key takeaway
A quick hitch should save you time without compromising safety. Never sacrifice compliance for cost — the consequences of an attachment falling can be severe and irreversible.
Types of quick coupler
Quick hitches fall into three broad categories. Understanding the differences will help you match the right type to your working environment.
Dedicated (system-specific) quick hitches
Dedicated couplers work only with attachments manufactured to the same pin geometry. The machine-side hitch and the attachment-side adapter are engineered to work together — there is no guesswork about compatibility.
- Higher safety: the attachment can only connect if it is genuinely compatible
- No secondary pin or tool needed for locking on most designs
- Consistent, predictable operation across your fleet
- Attachments must be purchased or converted to the same system
Harford's Safelock is the leading dedicated quick hitch in the UK market and is particularly popular with plant hire companies managing mixed fleets.
Mechanical quick hitches
Mechanical couplers (sometimes called pin-grab or manual hitches) use a lever or wrench-operated locking mechanism to grab the attachment's existing dipper pins. No auxiliary hydraulics are required.
- Compatible with most standard-pin attachments without modification
- Lower upfront cost — no need to convert your attachment fleet
- Requires a secondary locking check after connection
- Suitable for machines without auxiliary hydraulic circuits
The Pro-Lok is Harford's mechanical quick coupler, featuring a double-locking mechanism for additional security.
Hydraulic quick hitches
Hydraulic couplers are operated directly from the cab using a dedicated circuit. Locking and unlocking is controlled via a dashboard switch or joystick button — the operator never needs to leave the seat.
- Fastest attachment changes — ideal for high-frequency swaps
- Full cab control with no need to exit the machine
- Requires auxiliary hydraulic ports on the machine
- Higher initial investment; additional plumbing may be needed
- Safety interlocks are essential — ensure any hydraulic hitch has them
The Uni-Lok is Harford's hydraulic quick hitch, available for machines from 0.75 to 14 tonnes.
Safety standards for quick hitches
Safety note
Quick hitch failures have caused deaths and serious injuries on construction sites. Always buy from reputable manufacturers and follow the inspection schedule in your product manual.
Operators are responsible for ensuring that any quick coupler fitted to their machine meets the industry safety standard. Using a non-compliant coupler can result in enforcement action.
All Harford Attachments quick couplers are designed to meet International compliance standards. When evaluating any coupler, ask the vendor to confirm standards compliance.
Sound Advice for Operators
- Inspect the quick coupler visually before each shift — look for cracks, wear, or damage
- Ensure the locking mechanism is fully engaged before lifting any attachment
- Follow the manufacturer's inspection and maintenance recommendations
- Do not use a quick coupler that has been modified without compliance testing.
- Ensure all operators receive adequate training in the quick coupler installation and operation prior to use
Compatibility Check Table
Harford manufactures three core quick hitch product lines, each suited to different operational needs. Here is an honest comparison to help you decide.
| Feature | Safelock | Pro-Lok | Uni-Lok |
|---|---|---|---|
| Type | Dedicated | Mechanical | Hydraulic |
| Operation | Manual - Locking pin & handle | Manual / ratchet | One-switch cab control |
| Auxiliary hydraulics needed | No | No | Yes |
| Attachment compatibility | Safelock only | Standard 2-pins | Standard 2-pins |
| Attachment change speed | Under 1 minute | 2–3 minutes | Under 1 minute |
| Ideal for | Rental, Utility, End-User | Contractors, Utility | Contractor |
| Tonnage range | 1,650-19,800 lbs / 0.75 - 9 tonnes | 1,650-22,000 lbs / 0.75 - 10 tonnes | 1,650-30,800 lbs / 0.75 - 14 tonnes |
| Secondary retention | Built-in locking device | Double Lock | Double Lock |
Choose Safelock if...
You run a mixed hire fleet. Safelock standardizes the attachment pool as buckets are interchangeable. Zero-tool, quick, easy attachment changes.
View SafelockChoose Pro-Lok if...
You have a mixed attachment fleet and need to work with standard 2-pin attachments. Hybrid options are available if excavator brand changes.
View Pro-LokChoose Uni-Lok if...
You swap attachments many times per day or your work is on busy sites where you cannot leave your cab safely. Maximises uptime in high-productivity environments.
View Uni-Lok