JD450A
Feral as Fk 🐾
There you go.... Print it off, and tell em to roll it in a ball and shove it up there Arse.
There you go.... Print it off, and tell em to roll it in a ball and shove it up there Arse.
GazCro
Well-known member
Handy that as it's one of the hitches (on smaller machines) that i don't actually is the strongest built for reverse buckets. Never broke mine yet mind.
Randla
Interloper
Sorry Rory, I'm going to disagree with you here. (I acknowledge that I have trimmed the piece above, but hopefully not in a way that changes the message or context of what you have written)
Where the (reversed) bucket is directly pinned to the dipper then you are quite correct in saying that the risk of detatchment is not increased, but (leaving aside the semi-automatic hitches which you shouldn't see on sites these days),reversing the bucket on a pin-grab type hitch is not good for the following reason: When you are using a bucket in the conventional sense, the pirmary digging forces are on the hitch jaw closest to the digger, which is a fixed (and usually cast) item designed to take the maximum breakout force associated with that digger. If you reverse the bucket, the forces are now on the hitch ram and this is not what it was designed to do. For completeness, a semi hitch safety pin is designed, amongst other things, to hold the hitch closed against accidental operation of the hitch mechanism, not against the increased forces on the hitch ram which is now having to counter the bucket ram forces. Compare the size of the hitch ram to the bucket ram and I know which one my money's on.
Similarly, your point about S-type hitches is not fully developed. FIrstly, the S-standard is most closely associated with tiltrotators and they do not suffer the same problem I outlined in the paragraph above because they rotate the hitch with the bucket so that the open/shark jaw is aways facing the same way as the open face of the bucket. For this reason, when used underneath a tiltrotator, there is no 'bucket reversal'. You also make a point about some S-type hitches being 'not twin lock'. Let me at this stage make the point that, from a worldwide perspective, virtually all S-type hitches are not twin lock. Twin lock hitches are a UK phenomenum and are, IHMO, a fundamentally dangerous development, not from what they are designed to prevent, but what they allow an operator to do:
To divert; a twin lock device is designed to prevent the bucket or other attachment from detaching in the event that the second axle is not properly engaged by the pin grab, or if the hitch ram fails for some reason. The bucket will swing free, but not detach because the twin lock mechanism has grabbed the pin nearest the cab. A good thing, until you observe what a lot of operators do, which is use this feature to move buckets around site (usually at the end of a shift when they are tired) without fully picking them up with both axles. Not only is this bad practice, but it also can accelerate degradation of the twin lock mechanism. S-type hitch manufacturers (with one exception) have adapted their hitches for the UK market by fitting twin locks to sell their hitches, not because it's a good thing. They've done it because some main contractors will not allow non-twin lock hitches on their sites. I've had this discussion with a number of them over the years and they start by saying that they do it because 'it's the regulations'. Not true. There are currently two relevant regulations in play here: one European and one UK (HSE). The first is that the Operator must have read, understand and fully comply with the hitch manufacturer's operating instructions. The second is that the hitch must be so constructed that, in the event of a loss of hydraulic of other excavator power, the hitch must not be capable of allowing the attachment to become detached. That's it - there's nothing about twin lock in there.
It follows that if you reverse a bucket and use it as a face shovel, not only do you run the risk of degrading the hitch ram, but you also run the risk of doing the same to the twin lock mechanism.
You may extrapolate these arguments for the use of forks on an excavator. Clearly, unless you want to risk puncturing yourself whilst sitting in the cab, the best solution is to have the forks facing away from you. However, for the reasons above, doing this is going to put an amount of stress on the hitch ram that it was clearly not designed for. For this reason, the use of load tables with forks on an excavator needs to be very carefully read and, with reversed forks, I would argue cannot be applied. A fork manufacturer will give a calibrated figure (in my direct experience a TP(500) number in tonnes) which corresponds to the load capacity of the forks themselves. This needs then to be interpreted alongside the excavator load charts to give a safe load envelop for what's being picked up. I've yet to see any figures attributed to the (pin grab) hitch ram in this regard and, TBH, I wouldn't stand within a country mile of any digger operating a set of forks like this.
As will come as no surprise to any of you that know me, these are some of the arguments for investing in a tiltrotator, and a powerful secondary argument for the low build height of the S-type hitch.
All, as ever, IMHO
Robert
JD450A
Feral as Fk 🐾
No disrespect intended Robert, but the ram argument doesn't stand up for me. I'm quite certain that the amount of force that could be applied to a reversed bucket is far less than would be required to force the ram shut as the ram forces involved are on the weak side of the ram.Sorry Rory, I'm going to disagree with you here. (I acknowledge that I have trimmed the piece above, but hopefully not in a way that changes the message or context of what you have written)
Where the (reversed) bucket is directly pinned to the dipper then you are quite correct in saying that the risk of detatchment is not increased, but (leaving aside the semi-automatic hitches which you shouldn't see on sites these days),reversing the bucket on a pin-grab type hitch is not good for the following reason: When you are using a bucket in the conventional sense, the pirmary digging forces are on the hitch jaw closest to the digger, which is a fixed (and usually cast) item designed to take the maximum breakout force associated with that digger. If you reverse the bucket, the forces are now on the hitch ram and this is not what it was designed to do. For completeness, a semi hitch safety pin is designed, amongst other things, to hold the hitch closed against accidental operation of the hitch mechanism, not against the increased forces on the hitch ram which is now having to counter the bucket ram forces. Compare the size of the hitch ram to the bucket ram and I know which one my money's on.
Similarly, your point about S-type hitches is not fully developed. FIrstly, the S-standard is most closely associated with tiltrotators and they do not suffer the same problem I outlined in the paragraph above because they rotate the hitch with the bucket so that the open/shark jaw is aways facing the same way as the open face of the bucket. For this reason, when used underneath a tiltrotator, there is no 'bucket reversal'. You also make a point about some S-type hitches being 'not twin lock'. Let me at this stage make the point that, from a worldwide perspective, virtually all S-type hitches are not twin lock. Twin lock hitches are a UK phenomenum and are, IHMO, a fundamentally dangerous development, not from what they are designed to prevent, but what they allow an operator to do:
To divert; a twin lock device is designed to prevent the bucket or other attachment from detaching in the event that the second axle is not properly engaged by the pin grab, or if the hitch ram fails for some reason. The bucket will swing free, but not detach because the twin lock mechanism has grabbed the pin nearest the cab. A good thing, until you observe what a lot of operators do, which is use this feature to move buckets around site (usually at the end of a shift when they are tired) without fully picking them up with both axles. Not only is this bad practice, but it also can accelerate degradation of the twin lock mechanism. S-type hitch manufacturers (with one exception) have adapted their hitches for the UK market by fitting twin locks to sell their hitches, not because it's a good thing. They've done it because some main contractors will not allow non-twin lock hitches on their sites. I've had this discussion with a number of them over the years and they start by saying that they do it because 'it's the regulations'. Not true. There are currently two relevant regulations in play here: one European and one UK (HSE). The first is that the Operator must have read, understand and fully comply with the hitch manufacturer's operating instructions. The second is that the hitch must be so constructed that, in the event of a loss of hydraulic of other excavator power, the hitch must not be capable of allowing the attachment to become detached. That's it - there's nothing about twin lock in there.
It follows that if you reverse a bucket and use it as a face shovel, not only do you run the risk of degrading the hitch ram, but you also run the risk of doing the same to the twin lock mechanism.
You may extrapolate these arguments for the use of forks on an excavator. Clearly, unless you want to risk puncturing yourself whilst sitting in the cab, the best solution is to have the forks facing away from you. However, for the reasons above, doing this is going to put an amount of stress on the hitch ram that it was clearly not designed for. For this reason, the use of load tables with forks on an excavator needs to be very carefully read and, with reversed forks, I would argue cannot be applied. A fork manufacturer will give a calibrated figure (in my direct experience a TP(500) number in tonnes) which corresponds to the load capacity of the forks themselves. This needs then to be interpreted alongside the excavator load charts to give a safe load envelop for what's being picked up. I've yet to see any figures attributed to the (pin grab) hitch ram in this regard and, TBH, I wouldn't stand within a country mile of any digger operating a set of forks like this.
As will come as no surprise to any of you that know me, these are some of the arguments for investing in a tiltrotator, and a powerful secondary argument for the low build height of the S-type hitch.
All, as ever, IMHO
Robert
Likewise the main selling point of pin grabber hitches over other types was always the ability to reverse a bucket.
Regarding the S type I fully appreciate that my arguments aren't developed, I also agree on the principal that twin locks are a ridiculous UK phenomenon.
Regarding semi Q/Hs. Ultimately my view is they are like all things as safe as the operator involved..... There are still many about and a manual spring lock hitch relies on exactly the same safe working principals
The bigger issue that this all throws up is that of a bucket or forks should become detached the works should be planned and designed to prevent anyone being in harms way regardless of the machine configuration. This clearly isn't happening
Randla
Interloper
No disrespect taken at all Rory
but I'm still going to disagree with you.The reason there is a weak and a strong side to the ram (and a fast and a slow side, too) is because the cross sectional area (CSA) of the strong side is greater because it doesn't have the piston rod. For this reason the (excavator) oil pressure is working against a larger area and can produce a greater ram force. My argument is that the effetive CSA of the weak side of the bucket ram is still larger than the strong side of the hitch ram (these things are tiny in comparison) and, as such could be overwhelmed.
I take your point on the other matters
I probably haven't explained it very well, but there a bit here https://learnoilhydraulics.com/page...r-in-one-direction-and-faster-in-the-opposite that goes into more detail.
Robert
GazCro
Well-known member
I guess another thing to note re tiltys and hitch always being the correct way round is that many will be direct mounted but possibly a UK thing is top hitches which would then load the hitch the other way round.
Left hooker
Well-known member
V8Druid
do it as well as you can,but learn to do it better
and have far greater leverage than without the tilty
JD450A
Feral as Fk 🐾
That's it, pour the propellant on the fire
GazCro
Well-known member
Only way to stop it smokingThat's it, pour the propellant on the fire
doobin
Well-known member
No disrespect taken at all Rory
The reason there is a weak and a strong side to the ram (and a fast and a slow side, too) is because the cross sectional area (CSA) of the strong side is greater because it doesn't have the piston rod. For this reason the (excavator) oil pressure is working against a larger area and can produce a greater ram force. My argument is that the effetive CSA of the weak side of the bucket ram is still larger than the strong side of the hitch ram (these things are tiny in comparison) and, as such could be overwhelmed.
I take your point on the other matters
I probably haven't explained it very well, but there a bit here https://learnoilhydraulics.com/page...r-in-one-direction-and-faster-in-the-opposite that goes into more detail.
Robert
Yes but you need to take leverage into account.
JD450A
Feral as Fk 🐾
And the fact that on a JCB 220x LR the bucket ram retract stroke will be around 3/4" and the hill q/h ram is around 3" bore.....
Randla
Interloper
Agreed, Doob. Someone mentioned earlier that Hill, who do not make a bad product, have certified (one of?) their hitches for reverse functionality such as a face shovelling. For the avoidance of doubt, the comments I made earlier were directed at general pin-grab type arrangements which are just designed for normal operation. If you have the relevant Hill hitch (or one from another reputable manufacturer) that is certified for use in this way then clearly my comments do not apply.
I get the sense that the originator of the question is looking for an excuse for something or other and since Rory @JD450A has managed to get my head above the parapet on LinkedIn (cheers - I owe you for that............
) I will add another two penneth worth here.At Plantworx 5 years ago, a certain company - let's call them Brian Blessed - called in and asked why the hitch that we had lauched wasn't a twin lock, and could it be made so. I explained that it wasn't and why (amongst others it actively prevented the swinging bucket phenomenon I mentioned earlier). Cutting a long story short, they accepted it (and were still doing so when I left this January). The moral of this is that it is damn difficult to innovate in the UK construction industry and the default (usually driven by large site operators) is to close down what is not accepted (for whatever reason) by them as the 'norm'. If Hill have a hitch that works in face shovel mode, then great, and I hope that Sarah's research is nuanced enough to prevent another box ticking exercise.
Robert
JD450A
Feral as Fk 🐾
Your welcomehas managed to get my head above the parapet on LinkedIn (cheers - I owe you for that............
for the record it was either tag you or Taylor and I thought you would defend it best. Not out of spite or humor at all.Allow me to explain what happens with safety innovations IMHO
One Of Proturpin's engineers designs a totally unnecessary "safety Innovation... a salesman then sells this in bulk at a discount to a big contractor such as Flannels Plant.
Now the stage has been set, Flannels Rep sells the totally unnecessary device to a Main contractor such as Betty Bullfor on the premise that it will make there sites safer. They then Insist on that item being Mandatory..... which suits Flannels and Proturpin and fucks everyone else in the arse..... (Just my personal opinion).
What is positive for H&S innovation fucks everything else tho.
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V8Druid
do it as well as you can,but learn to do it better
my old Miller grabber is impossible to drop anything out of with the pin in .... it's right tight behind the jaw .....
..........that'll test the QH/forks theories
hiluxman
Well-known member
Welcome to the UK, is all i can say.Your welcome
Allow me to explain what happens with safety innovations IMHO
One Of Proturpin's engineers designs a totally unnecessary "safety Innovation... a salesman then sells this in bulk at a discount to a big contractor such as Flannels Plant.
Now the stage has been set, Flannels Rep sells the totally unnecessary device to a Main contractor such as Betty Bullfor on the premise that it will make there sites safer. They then Insist on that item being Mandatory..... which suits Flannels and Proturpin and fucks everyone else in the arse..... (Just my personal opinion).
What is positive for H&S innovation fucks everything else tho.
Here we only make stuff up to justify a new job to ensue its looked at and so numpty can get a job too driving a machine.
Here in the UK we don't like change and dream up new jobs or innovations rather than having balls to get rid of numptys which shouldn't be let loose with a skipping rope
Left hooker
Well-known member
Selector grab should be added to list with forks and bucket reversed
S
Smiffy
Well-known member
Tree shears should be and what about fly jibs like lpgeddie has on his liebherr
But as I said before if the rear jaw is sliding type then forcing the ram is irrelevant as the quick hitch ram moves in a different direction to the force being applied
It's only if the rear jaw is a hinge that it could theoretically loose grip
Lancs Lad
Well-known member
First time I heard of Eddie on here..what's he up to these days? Sorry I don't do FB.
V8Druid
do it as well as you can,but learn to do it better
neither does he
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