Excavator quick coupler

01

Match the machine class, attachment pins and hydraulics

engcon's quick coupler data sheet lists sizes S30 to S80 for base machines from 3,300–5,500 lb (S30) to 59,000–88,000 lb (S80), with axle diameters from 1.2 to 3.1 in, widths from 7 to 23.2 in and weights from 44 to 816 lb. Its couplers are automatic (fully hydraulic, tools changed from the cab), hydraulic (hydraulic locking but manual connection of hoses and electrics) or mechanical (no hydraulics); the recommended open/close pressure is 3,200 psi and the maximum auxiliary pressure 5,080 psi. [1]

Steelwrist's S30 data sheet, for 0–2 t compact excavators, gives a 25–35 mm pin diameter range, 85–180 mm pin centres, a maximum dipper arm width of 125 mm, 82 mm build height and a weight from 15 kg, with mechanical snap-in (semi-automatic) or hydraulic (automatic) locking to the symmetrical standard. [2]

Editorial calculation: 3,200 psi is about 221 bar (22 MPa); an S80 at 816 lb (about 370 kg) on a 59,000 lb (about 26.8 t) machine adds roughly 1.4% of machine mass at the arm tip. Ask the supplier to state coupler weight and its effect on rated lift capacity. [1]

Give the supplier the machine make, model and operating weight, dipper arm width and pin, every attachment's pin diameter, pin centres and ear width, locking type wanted (mechanical, hydraulic, automatic), available hydraulic pressure and circuits, auxiliary oil and electric pass-through, lifting eye needs, applicable standards (ISO 13031, EN 474-5) and quantities.

02

Check locking safety, retaining pins and inspection

The UK Health and Safety Executive's safety alert on quick hitches reports four fatalities in the year to December 2007, all with semi-automatic hitches, and states that in all of these fatal incidents a retaining pin or bar was missing; a hitch may operate for some time without it and then swing open or drop the attachment without warning. [3]

HSE asks for operator training on the specific hitch, the manufacturer-specified retaining pin to be on the machine, a check that the pin is in place before work and at every attachment change, and a ban on substitutes such as large bolts or wire. Under the Lifting Operations and Lifting Equipment Regulations, a hitch permanently on the machine is thoroughly examined every 12 months (or as a competent person decides), and one not permanently attached is treated as a lifting accessory with six-monthly checks. [3]

Steelwrist's S30 has a Front Pin Hook that holds the tool's front shaft to reduce the risk of dropping it if it is not connected correctly, and is stated to comply with EN 474-5 and ISO 13031:2023. [2]

Editorial note: ask suppliers how their coupler retains a tool if the hydraulic or mechanical lock is not engaged, and for the declaration of conformity to the standard named.

03

Attachment makers that also list couplers

Listings include quick couplers alongside excavator buckets, breakers, grapples and other attachments.

04

Check hitch markings, pin fit and hose burst valves before use

WorkSafe New Zealand's quick hitch guidance says a hitch holds the attachment with either a manual locking pin or an automatic hydraulic pressure hitch, and that an attachment of the wrong size may not be secured properly, so the hitch fails. It lists four items a quick hitch should clearly display; the table sets them, and the pin and valve rules, against what to ask the supplier for. [4]

Safety pins and other shaped securing devices should meet the hitch manufacturer's specifications and stay with the excavator or hitch when not in use; attachments should have the correct pin centres and diameters, and substitutes such as a structural bolt or reinforcing bar are not to be used. Painting the area around the pin holes a bright contrasting colour makes a removed pin visible. The operator should check that the pin is in place or the automatic system has engaged before starting work and when fitting a different attachment, and an exclusion zone should be set below and around the bucket. [4]

Hose burst protection valves must be fitted to all new and used hydraulic excavators with an operating weight of 7 tonnes or more after 1 January 2016. WorkSafe notes this guidance has not been updated for the Health and Safety at Work Act 2015 and its regulations. [4]

05

Frame, lock, cylinder and retention on a quick coupler

Safety retention is the part the HSE alert turns on; the frame, lock and pass-through rows draw on the engcon and Steelwrist sheets.

06

Pin sizes, pressures and weights from one compact and one full range

Each published value here comes from Steelwrist's 0–2 t S30 or from engcon's S30–S80 range, so ask for the same field on the coupler size that fits your machine. Flow, temperature, hardness and IP rating are not given in the sources on this page.

07

Send the machine, pin and safety data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Machine: [make; model; weight]
Pins: [diameter; centres; ear width per tool]
Locking: [mechanical; hydraulic; automatic]
Hydraulics: [pressure; circuits; pass-through]
Safety: [retention type; ISO 13031; EN 474-5]
Supply: [lifting eye; quantity]

See manufacturer records Send an enquiry through CNFX