Following the M20 bridge debacle, it was suggested in another forum that it was likely that the excavator arm had “elevated itself” as this kind of thing “happens all the time” and that it happens when an arm isn’t properly secured. (This was before the actual facts came out and was just supposition).
Anyhow, I’m well aware of the phenomenon in tipper trucks, we had a fairly spectacular one on the M80 in Scotland a number of years back but I can’t see how this can happen with an unpowered excavator being transported unless there is some sort of hydraulic pressure accumulator (and vibration causing a valve leakage say).
So, can it happen? Has it happened? Are there any web links to an incidence of this happening? Are there specific rules regarding the transport of excavators to stop this kind of thing happening (like chaining down the arm/bucket etc)?
I’ve never known of a boom raising itself, they will drop if left raised, hence you lower all booms when parking up or leaving unattended. The machines will slew in transit if not suitably secured (anyone recall a fatal a few years back where a backactor swung out on a roundabout?).
Tippers shouldn’t raise whilst in motion unless the pto is left on and someone moves the tipping lever. In any case in modern tippers the pto automatically disengages when moving regardless of the switch position.
It’s possibly more an issue of relying on hydraulic pressure to ‘hold’ an arm in place rather than hydraulic pressure causing it to move.On that note yes buckets/arms should be chained down seperately.
Carryfast:
It’s possibly more an issue of relying on hydraulic pressure to ‘hold’ an arm in place rather than hydraulic pressure causing it to move.On that note yes buckets/arms should be chained down seperately.
Thanks. I can see why an arm should be secured against movement, you don’t want one swing around like in the linked incident. I’m just more curious about whether the arm can rise, and if so, are there recorded instances of arms colliding with bridges due to this.
Carryfast:
It’s possibly more an issue of relying on hydraulic pressure to ‘hold’ an arm in place rather than hydraulic pressure causing it to move.On that note yes buckets/arms should be chained down seperately.
Thanks. I can see why an arm should be secured against movement, you don’t want one swing around like in the linked incident. I’m just more curious about whether the arm can rise, and if so, are there recorded instances of arms colliding with bridges due to this.
Logically securing it against movement would secure it laterally and vertically anyway regardless of the question.Although I certainly carried dozers/shovels in which although the bucket/arms couldn’t possibly move laterally,vertical movement would have required hydraulic pressure,as opposed to loss of pressure,to lift it which is why the idea of vertical movement was never given any thought.Although with hindsight now I would have chained down the bucket/arm as a matter of course anyway.
When I was working for Richard Long on the JCB jobs we never put chains on the boom just a strap to either side and I’ve never known anyone else to use chains in this way either. Only ever used chains over the tracks. Google weren’t yer friend this time CF !!
And it would be physically impossible for the boom to raise itself unless the engine was running and someone was working the control to raise it
raymundo:
When I was working for Richard Long on the JCB jobs we never put chains on the boom just a strap to either side and I’ve never known anyone else to use chains in this way either. Only ever used chains over the tracks. Google weren’t yer friend this time CF !!
And it would be physically impossible for the boom to raise itself unless the engine was running and someone was working the control to raise it
As I said the difference is that ‘loss’ of hydraulic pressure could cause lateral movement of an arm being held in place by hydraulic pressure alone.But you’d obviously need hydraulic pressure to lift it.Which would logically mean engine running and actuation of the relevant control.That’s just logic zb all to do with google.
The answer is no. Due to gravity. The engine would have to be powering the hydraulic pump and the manipulator to be operated. Dipper or lift-arms should always be secured down and it can’t go sideways either. Chain down trackframe,dipper,buckets,and hammer.Get out measuring stick,job done
I have always been astonished just how many 13 tonne excavators are transported with just the one and only chain, or frequently the one strap, thrown over the tracks.
jackdaniels:
Following the M20 bridge debacle, it was suggested in another forum that it was likely that the excavator arm had “elevated itself” as this kind of thing “happens all the time” and that it happens when an arm isn’t properly secured. (This was before the actual facts came out and was just supposition).
Anyhow, I’m well aware of the phenomenon in tipper trucks, we had a fairly spectacular one on the M80 in Scotland a number of years
Ah Denny Tippers ,am sure I have a pic of that somewhere lol
jackdaniels:
Following the M20 bridge debacle, it was suggested in another forum that it was likely that the excavator arm had “elevated itself” as this kind of thing “happens all the time” and that it happens when an arm isn’t properly secured. (This was before the actual facts came out and was just supposition).
Anyhow, I’m well aware of the phenomenon in tipper trucks, we had a fairly spectacular one on the M80 in Scotland a number of years
Ah Denny Tippers ,am sure I have a pic of that somewhere lol
cav551:
I have always been astonished just how many 13 tonne excavators are transported with just the one and only chain, or frequently the one strap, thrown over the tracks.
Agreed. Or smaller diggers in a ro-ro skip. I use so many chains it’s unreal,pay attention to how it’s loaded,measure it,then set the height indicator accordingly.Usually around 14’. I’m mainly around the tunnel/M25 where DVSA lurk. Whatever you drive,if you get a pull and your height indicator doesn’t match what you are,you’re in the [zb]
cav551:
I have always been astonished just how many 13 tonne excavators are transported with just the one and only chain, or frequently the one strap, thrown over the tracks.
Or when Farmer Giles decides to go ditching and puts his clapped out FH130 onto a rotten trailer behind his subsidised John Deere with no chains at all. You can’t tell him to do otherwise because you “don’t understand farming…”
jackdaniels:
Following the M20 bridge debacle, it was suggested in another forum that it was likely that the excavator arm had “elevated itself” as this kind of thing “happens all the time” and that it happens when an arm isn’t properly secured. (This was before the actual facts came out and was just supposition).
I’m well aware of the phenomenon in tipper trucks, we had a fairly spectacular one on the M80 in Scotland a number of years back
So, can it happen? Has it happened? Are there any web links to an incidence of this happening? Are there specific rules regarding the transport of excavators to stop this kind of thing happening (like chaining down the arm/bucket etc)?
I drive a grab lorry,i have done for about twenty years-yes there can be some lateral movement,but never ever can the boom lift itself up ffs
and what is this “phenomenon in tipper trucks”? sounds like ■■■■■■■■ to me
[/quote]
jackdaniels:
Following the M20 bridge debacle, it was suggested in another forum that it was likely that the excavator arm had “elevated itself” as this kind of thing “happens all the time” and that it happens when an arm isn’t properly secured. (This was before the actual facts came out and was just supposition).
I’m well aware of the phenomenon in tipper trucks, we had a fairly spectacular one on the M80 in Scotland a number of years back
So, can it happen? Has it happened? Are there any web links to an incidence of this happening? Are there specific rules regarding the transport of excavators to stop this kind of thing happening (like chaining down the arm/bucket etc)?
I drive a grab lorry,i have done for about twenty years-yes there can be some lateral movement,but never ever can the boom lift itself up ffs.
and what is this “phenomenon in tipper trucks”? sounds like ■■■■■■■■ to me.
[/quote]
Not ■■■■■■■■ at all (from what Ive read). Tippers have an engine driven hydraulic pump to power the ram. This pump is normally only engaged when the vehicle is tipping. If the pump is left engaged whilst the vehicle is in motion, a leaking control valve can lead to the ram slowly extending while the vehicle is in motion.
jackdaniels:
Following the M20 bridge debacle, it was suggested in another forum that it was likely that the excavator arm had “elevated itself” as this kind of thing “happens all the time” and that it happens when an arm isn’t properly secured. (This was before the actual facts came out and was just supposition).
I’m well aware of the phenomenon in tipper trucks, we had a fairly spectacular one on the M80 in Scotland a number of years back
So, can it happen? Has it happened? Are there any web links to an incidence of this happening? Are there specific rules regarding the transport of excavators to stop this kind of thing happening (like chaining down the arm/bucket etc)?
I drive a grab lorry,i have done for about twenty years-yes there can be some lateral movement,but never ever can the boom lift itself up ffs.
and what is this “phenomenon in tipper trucks”? sounds like ■■■■■■■■ to me.
Not ■■■■■■■■ at all (from what Ive read). Tippers have an engine driven hydraulic pump to power the ram. This pump is normally only engaged when the vehicle is tipping. If the pump is left engaged whilst the vehicle is in motion, a leaking control valve can lead to the ram slowly extending while the vehicle is in motion.
I’m sure someone will know for sure though.
[/quote]
jackdaniels:
Following the M20 bridge debacle, it was suggested in another forum that it was likely that the excavator arm had “elevated itself” as this kind of thing “happens all the time” and that it happens when an arm isn’t properly secured. (This was before the actual facts came out and was just supposition).
I’m well aware of the phenomenon in tipper trucks, we had a fairly spectacular one on the M80 in Scotland a number of years back
So, can it happen? Has it happened? Are there any web links to an incidence of this happening? Are there specific rules regarding the transport of excavators to stop this kind of thing happening (like chaining down the arm/bucket etc)?
I drive a grab lorry,i have done for about twenty years-yes there can be some lateral movement,but never ever can the boom lift itself up ffs.
and what is this “phenomenon in tipper trucks”? sounds like ■■■■■■■■ to me.
Not ■■■■■■■■ at all (from what Ive read). Tippers have an engine driven hydraulic pump to power the ram. This pump is normally only engaged when the vehicle is tipping. If the pump is left engaged whilst the vehicle is in motion, a leaking control valve can lead to the ram slowly extending while the vehicle is in motion.
I’m sure someone will know for sure though.
[/quote]
if this did happen surely the bloody driver would see it in his mirrors!!!
i’m pretty sure every tipper ive driven knocks the pto off with the handbrake anyway?
if it doesn’t then its driver error for not disengaging the pto before setting off.
