Common Terms

Just so we're speaking the same language





Any tool, coupler, hitch, grab, spade, blade, ripper or bucket attached to the end of the dipper arm of an excavator. Attachments are removeable and interchangeable.

coupler or hitch

A device that facilitates the interchange of attachments without the need to manually pull both pins. A coupler or hitch is also classed as an attachment.

mechanical coupler

A coupler that does not require hydraulic lines to install or operate, but which is fixed to the attachment by manual input, either by a ratchet or by pulling a draw pin.

hydraulic coupler

A coupler that uses the machine's primary hydraulic to facilitate the attach and detach operation for attachments. An operator can change attachments from within the cab in 20 seconds.

I-Lock coupler

The I-Lock is a patented hydraulic coupler from Wedgelock that includes three major safety features and the ability to fit a wide range of attachments from multiple manufacturers within a weight class.

bucket pin

Bucket pins are medium tensile steel and are used to fix attachments to the excavator. Pins used for the boom and dipper arm operation are OEM pins and have different strength and wear requirements. Bucket pins are designed to take the wear upon themselves and thus protect the coupler and attachments.

FRONT of coupler/ attachment

The FRONT of the coupler or attachment is the end closest to the excavator cab. This is the side you see when the attachment is down or extended.

REAR or BACK of coupler/ attachment

The REAR or BACK of the coupler or attachment is the end furtherest away from the excavator cab. This is the side you see when the attachment is fully curled.


On the I-Lock coupler the knuckle (or SAFETY KNUCKLE) is the spring-loaded locking feature on the FRONT (closest to the cab) that first engages the attachment pin. The knuckle is painted green for easy identification, or in the case of older I-Lock couplers the knuckle is red. The knuckle engages without any hydraulic or electrical action necessary.

cylinder (coupler)

The valve operated hydraulic mechanism that drives the coupler wedge to lock the rear pin.


The wedge, or Primary Wedge, is the hydraulically powered sliding component that engages the REAR pin and LOCKS the attachment to the coupler. The wedge is controlled by the operator during the attachment operation.

lifting eye

A purpose-designed ring on a coupler or hitch for the attachment of a chain or D-ring, to use the excavator arm as lifting device. All Wedgelock couplers have a weight lifting limit stamped on them.

bolt on edge

An extra blade or edge bolted to the cutting or leading edge of a cleaning or wide bucket.

side cutters

Additional cutting blades bolted to the side edges of digging buckets.

wear strips

Additional strips of steel welded to the outside of buckets to protect the bucket structure from wear. Often utilised when hard materials like rock come into contact with the bucket.