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Arrow-white What is Breakout force?

Posted by Jacob Hart

Aug 25, 2020

| |
7 mins read

Breakout force is an essential ingredient in excavators; it's the measurement of just how much power can be exerted at the tip of the attached bucket or implement from curling towards the cab. A higher breakout force number means more digging and lifting capability.

Many factors influence how much breakout force can be exerted by an excavator, for example:

  • The size of the crowd hydraulic cylinder (ram).
  • How much hydraulic pressure is supplied to the cylinder.
  • The distance between the dipper pin and dog bone pin.
  • + More

The majority of excavator manufacturers publish their excavator's breakout force potential, which is worked out using an accepted common standard in the industry such as the SAE J1179 standard 🡭 or ISO 6015:2016 🡭. However, it's always worked out based on their standard GP bucket, direct pinned to the excavator, when a coupler or different buckets are fitted, the breakout force potential is changed.

Installing a quick coupler (or anything that adds height/distance between the dipper arm and the attachment) to your excavator, reduces the breakout force as the mechanical advantage is reduced. A quick coupler/hitch adds that extra height between the dipper pin (curling pivot point) and the cutting edge of the bucket, increasing the force required to overcome resistance at the end of the attachment.

Different excavator Couplers compared in height configurations

Can an excavators breakout force be improved?

The simplest way to influence the breakout force on an excavator is by installing the shortest coupler and attachments. By making the distance between the dipper pin and the cutting edge of your bucket (coupler height + bucket height) as low as possible, breakout force will be increased over taller setups.

Another way to improve the breakout force is to use a squatter bucket – enabling a shorter height between the bucket pin and the cutting edge. Like the coupler, this will decrease the height and increase breakout force potential. However, this will come with a compromise on the capacity of your bucket; consideration should be given whether maximum performance will benefit productivity, as more height and bucket capacity (reduced breakout force) may not adversely affect practical digging capability.

Several Bucket sizes compared - performance versus capacity

How much impact do quick couplers have on breakout force? 

By choosing a shorter quick coupler, less potential breakout force will be lost, while gaining the extra productivity afforded by quick couplers and tilting couplers. In this comparison, based on the SAE J1179 standard, we compare the Attach2 Heli-Tilt Coupler (SKU: SGHT-65) to 2 other popularly available brands of tilt motor couplers in the same weight range. Both fitted to the same 12-tonne machine.

  • The Heli-Tilt coupler's pin to pin (direct) height is 503 mm and has 153 kN of potential force.
  • Other brand A coupler's pin to pin (direct) height is 596 mm and has 126 kN of potential force.
  • Other brand B coupler's pin to pin (direct) height is 623 mm and has 116 kN of potential force.

Attach2 Heli-Tilt comparison to other tilting quick couplers

The breakout force difference is significant between both couplers, the Heli-Tilt maintains 21% more breakout potential over brand A and 32% over brand B. That extra 21% or 32% of power can make difference to digging through hard material, lifting heavy items and fuel economy.

Next time you're purchasing a quick coupler (especially a tilting coupler) ensure you ask about its pin to pin (from the centre of the pin, and whether that measurement includes offset) height. By utilising a coupler with a low height, you maximise your excavator's performance while enhancing productivity.

Breakout Force article terms explained:

kN - Kilo Newtons. A metric unit of 'work done'. 1 Newton is the force needed to accelerate 1 kilogram to 1 metre a second squared. 1 Kilo Newton is 1,000 Newtons. Further explanation 🡭

Potential Force - The maximum potential force as calculated in kN to the SAE J1179 standard. This differs to the ISO standard. Measurements from the two can yield different results as the SAE standard is a mathematical simulation and the ISO standard is a practical test.

Pin to pin (direct) height  - In this context this measurement is derived from the distance between the centre of the front coupler mounting pin to the centre of the front attachment pin in a straight line. This distance measurement takes into account the 'offset' between these two pin, as they are rarely perpendicular. This measurement can also be different from what's published by manufacturers, as most refer to distance between the two pins at 90°. Offset has an equal affect on the breakout force calculation.

*This information is accurate to the best of our knowledge and at the time of publishing. It is not intended to mislead or deceive.

Product Explainer Couplers

Jacob leads a team of professional marketers who creatively execute Attach2's marketing strategy.

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