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Increasing safety for Surface Drilling on a rockface.

25/12/2014

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One way to drill a rock face is to abseil down and go for it (hand scaling) . However there are safer ways of doing it. Here are two different contrasts.  A good old scale down the wall system (picture on the left) and a unique drilling system which increases user safety, comfort and was able to increase productivity rates (Watch VIDEO here ). 

Engineered slopes require stabilization to ensure their long-term viability and reduce localized slope failure from erosion and rockfall.  The drillers place tensioned steel bar into the rock face increasing the normal force friction and shear resistance along discontinuities and potential failure surfaces. They are applied in a pattern or in a specific block area. 

So it requires good access to the rock slope. Visible bolt ends and hex nuts may need to be covered with shotcrete to improve aesthetics (by the way my first dissertation was designing a robotic shotcreting rig) . The hand scaling is the most common and inexpensive form of scaling. 

Your options are workers will rappel from the top of the slope , work out of a crane or man lift basket scaling a slope at one time. But have a look at the video its a better method as its safer and can become highly productive for the contractor. 

VIDEO LINK 
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Free Online Education- To certify or not to certify that is Alison's big question

20/12/2014

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There are many free online education courses available. I've tried a few and there are sites which simply give you free training. One site I like to visit is Khan Academy on youtube. 

I came across Alison'c certified courses and was very impressed with the content as I sampled a couple courses for a test run. the Diploma of Sustainable Development and Diploma of Systems Engineering. 

The founder says to have his course certified by a third party will cost students money. He was recently in Australia and I quote a part of the article from his speech.

 "Last week, Feerick asked an ADC Forum of education executives and entrepreneurs what they would trust more when picking a hotel: being a member of the local hoteliers federation or having high scores on TripAdvisor? The room went for TripAdvisor and Feerick had his gotcha! moment. If credibility is based on market feedback, then formal accreditation could face a challenge.


I personally think its not an equitable comparison of tripadvisor ( by the way I use trip advisor a lot) and a formally recognized certified education. I think third party certification as well as the location of the institution is important and establishes a level of quality at the same time I think courses like Alison are valuable but they are still a long way off being a viable alternative for employers. 



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Know thy Imposed Loads - Fluid Power Design

7/7/2014

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Reading a few posts on hydraulic forums I still see some commentators will dive straight into circuit design recommendation without asking about the nature of the imposed loads and other factors which have a profound affect on the system design. This only leads to poorly designed systems or far worse, systems which are not fit for their purpose and will need major rectification.

One example is a recycling plant machine design I was involved with. The start up power was not considered as significant and the whole design was based on normal running. The result was an underpowered hydraulic system. Fortunately changing to variable power control devices fixed the issue but the intended overall production rate was less than required and with lots of finger pointing at the time.

Another example, we were breaking axles on a mobile machine driving down hill, scratching our heads saying "don't you break axles going up the hill?" No, since mechanical inefficiencies work backwards in a system on a down hill run and become significant with large gradient differences. A simple fix was set a cross port relief for up the hill and another different setting for down the hill. I bet the guys who designed The Titanic wished it was that simple!

Anyhow I'm guilty and seen others do so many times is not considering the nuances of the imposed loads and straight away begin a schematic design and even component selection of a circuit only to do major changes when the "goal post moves" due to new loads being included, which results in wasting time, money and loss of the client's confidence.

A brief example to help make the idea clearer.

Some questions I asked based on a project of a mobile drilling machine.

Imposed Loads:

1. What happens: When the drill breaks through, the drill binds, hammering whilst drilling, to the torque when drilling through different strata, drill mast movement while drilling.

2. From that: We had to ensure machine stability, protect the hydraulic motor from over speeding, methods to control the feed rate, limit the drill force.

Providing a more comprehensive circuit than just turning a hydraulic motor.

The moral to the story is ti think about the nature of the load, come up with the pertinent questions, have some expectation as how it will behave then begin to design an appropriate system.

As Sun Tzu said in The Art of War "If you know the enemy and know yourself you need not fear the results of a hundred battles" well maybe he really meant not fear a hundred hydraulic circuits.

Next: using relevant Standards in fluid power design ( possibly more exciting reading than Harry Potter)



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"The only thing that interferes with my learning is my education"...Albert Einstein . 

13/5/2014

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EXPENSIVE EDUCATION
Does the "Clever Country" need to be a rich country? The cost of higher education is becoming more synonymous to simply how much future debt will I have.  Higher education is not the be all and end all but simply one of the best ways to understand some of the deeper meanings of life. However higher education is becoming out of the reach of many people due to the costs involved.

Typically an undergraduate degree in Australia is $42k, in the USA $ 39k and in the UK $33k. Australia is one of the most expensive places to obtain a degree. 

I'm currently doing a post graduate Master of Engineering Science which will cost approximately $45k , with some government support that will reduce to $25k (although it's really the tax payers who foot the government support). Will that degree pay for itself in the long run? Probably not! If I want to continue to a Doctorate that's about $80k. 

Many say a better World is an educated world? I believe in that. 

So should we really be making education so expensive at the determinant of our planet? 

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Hydraulic design schematic for operating hydraulic cylinders in series and parallel

13/5/2014

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Mobile hydraulic drive designers make use of changing the state of motor circuits from series to parallel when "on the run" so vehicles can have a wide power range of speed and torque i.e increased gearing options.

Doing the same with hydraulic cylinders operating in series and parallel is just as easy. The issues to look out for are:
1. Intensification
2. How to easily re-position the cylinders from either parallel to series configuration i.e 180 degrees out of phase or in-phase.
3. Cavitation 

Here is a simple solution and modification HADES made to a CLARK 18T Container forklift. The CLARK forklift carrier needed the fork tynes to have a side shift option as well as the normal extend and retract.
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Becoming a better Engineer - for this century today

3/12/2013

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The engineer of old isn't about number crunching and formulas, having a slide rule in the top pocket staring over the top rim of their glasses. It's about becoming creative and innovative to solve problems and to do what society values. 

Ok so that is probably obvious but what isn't so obvious that the ideas come from century old philosophy.

Take a look at this TED video on the simple ideas of what makes a good engineer today.




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No Frills Truck airbag weighing systems - a cost effective way for getting the job done.

8/11/2013

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There are a few commercially available methods to weigh truck pay loads. Some use load cells which is possibly the most accurate but a close second is measuring the airbag pressure to calculate the load. Loads cells are expensive and the use of  airbag pressure still gets the job done. There are limitations with all weighing systems mostly the vehicle needs to be stationary, variations in temperature causes discrepancies for airbags in the read out and if the load is not uniformly distributed over the axles measuring only at one point will allow for further errors. 

We devised a simple cost effective system that allows anywhere from measuring one point (for liquids) to multipoints (for solids and multi axles) with temperature compensation. It has preset density values for selected products or a user defined density parameter. This airbag weighing system costs less than half to a third of the price compared to anything on the market. Admittedly its no frills but gets the job done!

The whole kit consists of a programmed smart controller, a IP65 fully protected Screen, a cable and transducer, simple to install or refit onto an existing truck.

Below is how a basic air bag system works:
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How a concrete pump works

31/10/2013

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A concrete pump is relatively simple reciprocating pump but the synchronization or phasing between the two cylinder pistons need to be precise so that the flow is as constant as possible.  Otherwise you can develop a resonance on the placement boom (i.e the positioning arm will start to oscillate) and be hard to control and position the concrete. 

A line pump mounted on a truck or trailer with the poor (sic. pour ..haha)  concreter holding the end of the hose will certainly feel the effects especially on a slower cycles per minute rate e.g. during a block fill.

Here is a great description on a how a concrete pump works from REED USA or just watch this video.


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    Author

    Raymond Ho -
    Mechanical Engineer
    over 25 years experience in hydraulics and engineering

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