Safe Attachment Changeovers

December 7, 2021
Over the years the detach–attach operation of quick couplers has become increasingly foolproof. But there are a number of additional factors that will smooth the process and render it completely safe for everyone concerned.
Everyone wants a smooth, safe attachment change

An expanded look at the process of swapping buckets

Over the years the detach–attach operation of quick couplers has become increasingly foolproof, to the point that – for example – the latest tenX system from Wedgelock is a simple two-step process. No more waiting for timers or pressing multiple buttons in the correct sequence or entering passwords on keypads. No more frenzied action to complete the operation before timing out. 

With tenX couplers, it’s ‘click the switch and lift away’ then ‘engage next attachment and click the switch’. Done.

There are, however, a number of other factors to consider in order to smooth the process and render it completely safe for everyone concerned. These apply to all operators in all situations – and to pretty much every brand of quick coupler. What follows are a few of the unspoken ‘rules’ of attachment changeover, and why they’re important.

Flat working surface

Some instruction manuals will specify a flat surface for attachment changeover, others will assume it’s a given. Some operators might even read the manual.

Buckets are mostly curved, and at the right angle can tip or roll. At the least, a tipped bucket will be more difficult to pick up again. At worst, it can injure or kill.

It’s also fair to note that even a largely flat working surface can contain irregularities, such as small dirt piles, debris or trenches. Therefore it’s vital that the operator makes sure that the surface that they’re using to set down the attachment is flat and clear of obstructions.

Setting down on an uneven surface can have catastrophic results

Curling

No, not the sport played in Southland. This is another aspect of attachment changeover that might or might not be explicitly explained in manuals (it definitely is in the tenX Operation Manual), and the importance of which is not always fully appreciated. But look at it logically; when you enact the procedure to release the attachment from the coupler, what happens?

Unless the coupler is curled so that the pins are oriented vertically, the attachment might simply fall off the coupler. Even if it doesn’t, it could still swing violently and become a hazard.

Releasing an attachment while horizontal can drop it!

Curling the coupler rests the front pin in the ‘C’ cavity so that the attachment can’t go anywhere. If the pins are aligned vertically, the rear pin will remain resting against the coupler when released – no swinging. It’s then easy to smoothly lower the attachment to the ground and uncurl the coupler.

When engaging the new attachment, curling also ensures that the rear pin is in place for locking to the coupler. Failure to curl far enough can result in the Primary Wedge (in the case of the tenX Coupler) missing the rear pin. 

Curling allows for a smooth set-down

Both of these factors are well known to experienced operators and are performed automatically. But every year there are buckets dropped or allowed to swing dangerously due to incorrect orientation of the coupler when the locking mechanism(s) are released. Even worse, there are still cases of buckets rolling down slopes or falling into trenches once let go.

And a final factor – pressure (revs)

The movement of the Primary Wedge (in tenX Couplers), whether engaging or disengaging, requires hydraulic pressure. Even at idle, the Primary Wedge will still move, but it won’t set any speed records. Wedgelock instructions contain the term ‘BUILD PRESSURE’ when detaching or attaching, in order to speed up the process. 

Some excavator brands and models automatically raise the revs/pressure when the coupler circuit is engaged, but many don’t. Without that little burst of pressure, it’s possible for an operator in a hurry to begin using the attachment before the locking process is complete.

And that’s it. We currently live in an age when our dual-locking quick couplers are safer than ever, and mishaps at changeover are extremely rare. But even the safest, most ‘idiot-proof’ systems can be compromised by not following basic instructions.


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