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Old 12th July 2011, 11:43   #721
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Default Re: The Heavy Trucks thread

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Originally Posted by sajo View Post
Yesterday for the first time, I saw the Mahindra Navistar 25 tonne in the chassis+cowl form.
Looks like they are not able to make a dent in the Tata+AL market with their fully built vehicles and have resorted to selling chassis.
There are segments where only cabs are prefered and haulage is not in that league.So as usual MN has taken a wrong call in launching products.
Better go with market rather than pulling to your side.
Remember my views on Daimler coming with cowl only option in haulage models!
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Old 12th July 2011, 17:45   #722
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Default Re: The Heavy Trucks thread

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Some more pictures. I was wondering what the device on the Scania frame is? It looks like it is some fail-safe device to keep the tipping body intact in case the kingpin connecting the body to the truck fails?
These are stabilizers to provide vehicle stability during tipping.
Normally these are provided only in Tip trailers as the tipping height is much higher unlike 31T rigid tippers!
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Old 12th July 2011, 18:14   #723
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Default Re: The Heavy Trucks thread

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These are stabilizers to provide vehicle stability during tipping.
Normally these are provided only in Tip trailers as the tipping height is much higher unlike 31T rigid tippers!
Could you explain a bit further as to how they help stabilize?

Another question, regarding 31T trucks - the separation between the two axles at the front, is greater than the separation between the two axles at the rear. Why?
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Old 12th July 2011, 18:49   #724
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Default Re: The Heavy Trucks thread

I think "stability" may be a wrong word to use here. It probably acts as a sort of extra support for the long tippers, to take certain amount of the load off the hydraulic arm.

As for the axles, the rear axles are always bunched together, as they hang from the same bogie suspension unit. While the front axles are largely independent of each other. They are suspended independently of each other, with the only connection between them being the steering mechanism for the 2nd front axle. If there is no active steering mechanism, like on the Tata 3118s, you can have the extra front axle well behind.
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Old 12th July 2011, 20:20   #725
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Default Re: The Heavy Trucks thread

It doesn't seem to take any load of the hydraulic arm. If you guys look at it closely, it doesn't have any hydraulic arm on it. It doesn't seem to be a load bearing device at all. It just looks like a hinge. Could it be that it helps the body fall back on to the frame properly without any disorientation?

I've always wondered about this, do you guys know where the motor/pump for the hydraulic arm is? How big are they and exactly which part of the engine is to power the pump? Is it the driveshaft? And does the driver control the pump via the accelerator (hence the engine noise proportionally growing with the ascent of the body)?

Last edited by D33-PAC : 12th July 2011 at 20:21.
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Old 12th July 2011, 20:59   #726
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Default Re: The Heavy Trucks thread

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Could you explain a bit further as to how they help stabilize?
Well the subject item is called a "Stabilizers". They are required for higher capacity tippers as the "centre of gravity" of the load is comparitively higher from the ground. This device helps to balance the load between the two sides of the chassis when tipping, as the tipper truck may not be on a flat surface (off-road conditions) every time while tipping. There are chances the tipper may tilt and overturn while tipping.
In other words, its similar to the "Balance rod" fitted in the front axle of trucks & buses.
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Old 12th July 2011, 21:24   #727
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Default Re: The Heavy Trucks thread

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Originally Posted by D33-PAC View Post
I've always wondered about this, do you guys know where the motor/pump for the hydraulic arm is? How big are they and exactly which part of the engine is to power the pump? Is it the driveshaft? And does the driver control the pump via the accelerator (hence the engine noise proportionally growing with the ascent of the body)?
The pumps are run off a separate shaft coming out of the gearbox. Its called a Gearbox with PTO, or power take off facility. A specific gear is engaged in the gearbox, which causes the gearbox input shaft to get coupled to the PTO shaft which can then be connected to anything you want. Thus the engine must rev to a certain point to provide enough torque to raise the load, either controlled electronically or by the driver pressing the accelerator.

Last edited by julupani : 12th July 2011 at 21:26.
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Old 12th July 2011, 23:03   #728
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Default Re: The Heavy Trucks thread

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Originally Posted by julupani View Post
The pumps are run off a separate shaft coming out of the gearbox. Its called a Gearbox with PTO, or power take off facility. A specific gear is engaged in the gearbox, which causes the gearbox input shaft to get coupled to the PTO shaft which can then be connected to anything you want.
Are you sure?
Normally PTO output is taken from the 'lay shaft' of the gearbox & PTO is engaged / disengaged pneumatically by tipper control valve. Gearbox will be slotted into 'Neutral' before engaging the PTO.
Some engines do have PTO output directly from the crank shaft (mostly at the front side of the engine, similar to Air compressor output)

Last edited by Mr.Boss : 12th July 2011 at 23:04.
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Old 12th July 2011, 23:06   #729
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Default Re: The Heavy Trucks thread

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Originally Posted by silversteed View Post
Could you explain a bit further as to how they help stabilize?
These as explained by transenger provides stability when the tipping is height is high. If you ask me how this provides stability then we should get into laws of forces in physics

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Originally Posted by silversteed View Post
Another question, regarding 31T trucks - the separation between the two axles at the front, is greater than the separation between the two axles at the rear. Why?
Quote:
Originally Posted by julupani View Post
As for the axles, the rear axles are always bunched together, as they hang from the same bogie suspension unit. While the front axles are largely independent of each other. They are suspended independently of each other, with the only connection between them being the steering mechanism for the 2nd front axle. If there is no active steering mechanism, like on the Tata 3118s, you can have the extra front axle well behind.
Suspension is not independent in all cases. Actros is always available with front axle load compensation with Non reactive suspension - Non independent in local terms.
The main reason being to ensure proper Turning circle Diameter

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Originally Posted by julupani View Post
I think "stability" may be a wrong word to use here. It probably acts as a sort of extra support for the long tippers, to take certain amount of the load off the hydraulic arm.
Hope the terminology is clear and the manufacturers are right using them


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Originally Posted by Transsenger View Post
.... This device helps to balance the load between the two sides of the chassis when tipping, as the tipper truck may not be on a flat surface (off-road conditions) every time while tipping. There are chances the tipper may tilt and overturn while tipping.
In other words, its similar to the "Balance rod" fitted in the front axle of trucks & buses.
There are still advanced control like Hydro pnematic lateral suspension as a standard feature in Ginaf.
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Old 13th July 2011, 07:27   #730
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Default Re: The Heavy Trucks thread

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Originally Posted by Mr.Boss View Post
Are you sure?
Normally PTO output is taken from the 'lay shaft' of the gearbox & PTO is engaged / disengaged pneumatically by tipper control valve. Gearbox will be slotted into 'Neutral' before engaging the PTO.
Some engines do have PTO output directly from the crank shaft (mostly at the front side of the engine, similar to Air compressor output)
There are quite a few methods actually employed and I just mentioned one which I think is the most common in use with tippers. Depending on the application and the kind of load suitable methods of PTO are used.

By the way I am not saying the you have to put the gearbox in 1st or 2nd or any such gear, but the main gearbox is put in neutral and another lever which controls a particular selector fork independently in the gearbox is used to start the PTO operation. Of course in modern gearboxes this can be done pneumatically instead of having an actual linkage.
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Old 13th July 2011, 10:52   #731
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Default Re: The Heavy Trucks thread

The hydraulic pump in the tipping system is driven by different mechanisms. For example, TML uses a APP (axial piston pump) which is directly mounted on the gearbox. Meanwhile for AL, earlier they had a PTO unit mounted by the side of the gearbox, which is then connected to the hydraulic pump by means of a shaft. But today AL used new model PTO which is mounted directly behind the gearbox and the hyd.pump is coupled on to it as a single unit.
In the old system, the PTO was engaged with the gearbox mechanically by means of a lever in the cab. When the driver moves this lever, the PTO driver gear engages with the counter shaft idler gear. This time the main gearbox is in neutral position and pumping rate is increased by acclerating the engine(increase the rpm). Today, this engaging mechanism is done by a pneumatic shifting cylinder. It is actuated by a switch in the cab.

There is another type of PTO, which is an independent unit mounted inbetween the gearbox and the differential. It similar to the transverse gearbox. In this the propeller shaft from gearbox is connected to the PTO. From this PTO there will be two shafts, one to the differential (drive axle) and other for the special applications mounted on the vehicle. This is used for applications like Fire Tender, Concrete Boom pumps etc, where the main engine act as as power source for auxilary equipment. While in operation, the main gearbox usually will be in 5th or 6th gear and no power will be supplied to the driven axles.

In addition to these, there other type of PTO which is mounted on the engine flywheel ring or timing gears etc depending on the applications.
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Old 13th July 2011, 11:43   #732
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Default Re: The Heavy Trucks thread

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Originally Posted by Transsenger View Post
The hydraulic pump in the tipping system is driven by different mechanisms. For example, TML uses a APP (axial piston pump) which is directly mounted on the gearbox. Meanwhile for AL, earlier they had a PTO unit mounted by the side of the gearbox, which is then connected to the hydraulic pump by means of a shaft. But today AL used new model PTO which is mounted directly behind the gearbox and the hyd.pump is coupled on to it as a single unit.
In the old system, the PTO was engaged with the gearbox mechanically by means of a lever in the cab. When the driver moves this lever, the PTO driver gear engages with the counter shaft idler gear. This time the main gearbox is in neutral position and pumping rate is increased by acclerating the engine(increase the rpm). Today, this engaging mechanism is done by a pneumatic shifting cylinder. It is actuated by a switch in the cab.

There is another type of PTO, which is an independent unit mounted inbetween the gearbox and the differential. It similar to the transverse gearbox. In this the propeller shaft from gearbox is connected to the PTO. From this PTO there will be two shafts, one to the differential (drive axle) and other for the special applications mounted on the vehicle. This is used for applications like Fire Tender, Concrete Boom pumps etc, where the main engine act as as power source for auxilary equipment. While in operation, the main gearbox usually will be in 5th or 6th gear and no power will be supplied to the driven axles.

In addition to these, there other type of PTO which is mounted on the engine flywheel ring or timing gears etc depending on the applications.
The first kind of system, like I mentioned, is most common in the tippers that we see. But the 2nd kind of system that is mentioned is generally used in two cases, one when the vehicle is likely to be moving while the PTO is in operation, and 2nd when a larger amount of power is required for the auxiliary equipment.
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Old 13th July 2011, 14:08   #733
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Default Re: The Heavy Trucks thread

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....This is used for applications like Fire Tender, Concrete Boom pumps etc,...
Spetic tank cleaners is another application!
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Old 13th July 2011, 17:23   #734
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Default Re: The Heavy Trucks thread

Which are the BS-III trucks available in the market now, particularly in the 16t or 12t segment? Does anybody know for sure?
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Old 13th July 2011, 17:34   #735
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Default Re: The Heavy Trucks thread

I am sorry mate, but either you have mistyped or are a bit out of touch. All commercial vehicles are now BSIII or higher, since last October.

And also, I dont think there are any 12ton trucks available any more either. Those probably died out half a decade ago. The only 12ton truck is probably the 12ton 4x4 truck made for the defence/paramilitary forces.
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