Tractors, Fifth Wheels 4 Contents

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Tractors, fifth wheels 4

Contents

TRACTOR ...... 2

COMPATIBILITY AS PER ISO 1726 ...... 3 Manoeuvrability...... 5

WHEELBASE ...... 7

POSITIONING FIFTH WHEEL ...... 8

ATTACHING THE FIFTH WHEEL...... 10

LOCKING FIFTH WHEEL AND MOUNTING PLATE ...... 11

RETROFITTING ANGLE BRACKETS ...... 11

REINFORCING FOR 6x4 TRACTORS WITH ANGLE BRACKETS...... 12

SELECTING ANGLE BRACKET OR AUXILIARY FRAME ...... 13

ANGLE BRACKETS ...... 13

AUXILIARY FRAME...... 13

TYPES OF FIFTH WHEEL ...... 17 2" kingpin ...... 17 3.5" kingpin ...... 17 Universally jointed ...... 17 Replaceable locking mechanism...... 18 Moveable...... 18 Raisable and lowerable fifth wheel ...... 18

FACTORY FITTED FIFTH WHEELS FROM SCANIA ...... 19 Calculating the D-value for tractors with semi-trailers ...... 20 Factory fitted angle brackets for different types of chassis ...... 21 Factory fitted moveable fifth wheels ...... 23

TRACTOR Using a tractor for a semi-trailer offers many oppor- tunities to solve a variety of transport needs using the same truck. However, using the flexibility of a tractor means that international and national legislation and standards must be complied with, when selecting the wheelbase and positioning the fifth wheel. Before coupling the tractor and semi-trailer, always check that they are built to the same standard. 4133

2 © Scania CV 2002 Tractors, fifth wheels 4

COMPATIBILITY AS PER ISO 1726 ISO 1726 is an international standard covering characteristics and location of the fifth wheel, and the space that must be available for the semi-trailer.

Technically, tractors and semi-trailers that comply with this standard can be combined. In addition to technical compatibility, regard must be taken to regulations concerning external dimensions and axle loads of the vehicle combinations.

According to the international ISO standard, the height of the fifth wheel (A) on a loaded tractor should be: A=min 1150 mm A = max 1300 mm

Fifth wheel height (A) for tractor without semi- trailer. A = max 1400 mm

Bulk goods tractor adapted for 2.9 m high container as per ISO. 1 2 Laden tractor. A = min 1025 mm A A = max 1100 mm

Unladen. A = max 1150 mm ß1 ß2

The limit for fifth wheel movement longitudinally and laterally should be: upwards: min 8° ( b1 ) downwards: min 8° ( b2 ) 26:4120 laterally: max 3° ( a1 = a2 )

In order to ensure adequate clearance between tractor and semi-trailer in all driving conditions, the tractor must permit a slope angle for the semi-trailer of at least: forwards: 6° ( w1 ) rearward: 7° ( w2 )

w1 w2 26:4126

NOTE: ISO 1726 7° ( w2 ) gives clearance above tyres with no consideration taken for any mud guards.

4 © Scania CV 2002 Tractors, fifth wheels 4

Manoeuvrability In order for the tractor to be freely manoeuvred, the diagonal front overhang of the semi-trailer (front swept radius D) must not exceed 2040 mm. (This figure corresponds to a front overhang of 1600 mm from the kingpin to the front edge of the semi-trailer with a trailer width of 2500 mm.)

The rear part of the tractor must also have requisite clearance. Minimum distance between kingpin and semi-trailer landing legs is designated G.

An additional clearance of 100 mm is recommended between radii J and G, to allow for the necessary angular differences between the tractor and semi-trailer. Check this dimension at G D an operating angle of 90°. J

J = max 1940 mm D = max 2040 mm G = max 2300 mm 4111 26:4111

In order to ensure that the semi-trailer has sufficient clearance in relation to the tractor, a hitch profile can be drawn up, giving essential dimensions. This profile is often called a swan-neck profile and permits interchangeability between all S tractors and semi-trailers built according to the ISO Y standard. Values matched to these dimensions are as follows: R

G S = min 750 mm Y = max4° 26:4110 R = max 450 mm G = min 2300 mm

In order to be able to haul a 13.6 m trailer (EU trailer) within a total length of 16.5 m, the distance between the front of the tractor and the centre of the fifth wheel should be no more than 4500 mm. 26:4130

Max 4500 mm

This is a short introduction to ISO 1726. For further details concerning this international standard or local standards please contact the appropriate national standards organisation.

6 © Scania CV 2002 Tractors, fifth wheels 4

WHEELBASE The choice of wheelbase is affected by factors such as the front overhang on the semi-trailer and regulations that govern the total vehicle length and the gross vehicle weight. This limits the choice of where to place the fifth wheel lengthways.

However, technically the following general rules apply: A truck with a long wheelbase is more susceptible to chassis frame vibration. Since the distance between the chassis frame support points (the front axle and the rear axle) is large, the natural frequency of the chassis frame will be low.

First and foremost a chassis designed for tractors, an A chassis, should be specified.

Otherwise: Select the shortest possible wheelbase. The wheelbase measurements to the right are primarily recommended for fifth wheel installation.

Chassis type Wheelbase (mm)

PR 4x2 3300, 3550, 3700 PR 6x2 AB 2900 PR 6x2 Z 3100 PR 6x2/4 3975, 4100 PR 6x4 3100, 3300, 3500 T 4x2 4300, 4700 T 6x2, 6x4 3900, 4300

POSITIONING FIFTH WHEEL In addition to that mentioned in the previous para- graph, there are several factors which affect the position of the fifth wheel. The semi-trailer must not strike the cab or the rear of the chassis frame, but handling must be good.

In order to utilise the maximum load-carrying capacity of the front axle, the fifth wheel is usually located far forward on long trucks, which increases susceptibility to chassis frame vibration.

If the fifth wheel is positioned centrally over the rear axle or over the theoretical bogie centre, this effect is decreased. On the other hand, steering is made less sensitive and the driver has poor control of the semi-trailer.

An intermediate position should be selected, pro- viding both good handling and acceptable axle load distribution.

If the distance between the fifth wheel and the rear axle section is large, the semi-trailer will endeav- our to displace the truck laterally when the semi- When deciding the location of the fifth trailer heels over (when cornering or skidding). wheel, always check the axle loads in This may be dangerous on a slippery road surface. each individual case. This effect varies with load and road conditions and depends on the magnitude of acceleration or retardation. Always check that the space between It is not possible to give precise recommendations the semi-trailer and the rear edge of the for positioning the fifth wheel that take into con- chassis frame is sufficient. sideration all factors, e.g. chassis type, wheelbase, chassis equipment, required axle loads and legal requirements.

8 © Scania CV 2002 Tractors, fifth wheels 4

The following instructions give general guide- lines for fifth wheel location. Experience shows that the vehicle unit will handle well when: - The fifth wheel of a two-axle tractor is located at B a distance of 10% of the wheelbase forward of the rear axle. - The fifth wheel of a three-axle tractor is located 26:4102 at a distance of 10% of the wheelbase forward of the theoretical bogie centre. The theoretical bogie centre is shown on the main dimension drawings. B = max. 600 mm This positioning gives relatively low front axle (from the factory 760 mm) load, which can be increased by positioning the fifth wheel somewhat further forward. In order to comply with EU directives concerning tractor combinations, the distance between the If the fifth wheel is moved too far forward, more front of the tractor and the centre of the fifth wheel than 700 mm ahead of the driving axle on two-axle should not exceed 4500 mm, see also page 6. vehicles, handling will be impaired and the risk of exceeding the permitted front axle weight is in- The fifth wheel on tractors with a plastic bumper creased. should then be mounted as indicated in the table below. Tractors with a steel bumper are 35 mm On 6x2/4 vehicles the fifth wheel is more than 700 longer, so the fifth wheel must also be positioned mm ahead of the driving axle and handling is im- 35 mm further forward. paired when driving with the tag axle raised, which could be considered an unfavourable characteristic. On chassis with a T cab which have a longer B = 260 mm for wheelbase 3300 4x2 wheelbase it may instead be difficult to position 510 mm 3550 4x2 the fifth wheel far enough to the rear without exceeding the maximum permitted rig length. 660 mm 3700 4x2 Fifth wheel mounting places a highly concentrated 935 mm 3975 6x2 /4 load on the chassis frame. 1060 mm 4100 6x2 /4 From the loading aspect the fifth wheel should A = 140 mm 2900 6x2 therefore be positioned no further than 600 mm ahead of the rear axle on a two-axle tractor. An exception to this are chassis that are adapted to On three-axle tractors, the fifth wheel is located as the tractor ex works and on which the fifth wheel set out in A in the diagram can be mounted in a pre-drilled position a maximum of 760 mm A = min 90 mm 6x2, 6x4A/B ahead of the rear axle. 100 mm 6x4Z A 26:4101

ATTACHING THE FIFTH WHEEL The fifth wheel should be attached to a mounting plate.

The mounting plate provides a suitable attachment 26:4127 for the fifth wheel against the angle brackets or 40 8 auxiliary frame. r20 r20 2 2 A suitable design of mounting plate is shown in the adjacent figure.

One of the mounting plates in the adjacent figures can be used on trucks that require particularly low fifth wheel heights, In order to avoid the mounting plate being bent down, the cross members under- max 100 neath should be used.

If low angle brackets are used, the end surfaces on min 40 12 30 the mounting plate must not chafe the chassis 120 frame. This may cause damage to the chassis r 20 min 40 frame. 4106

The end surfaces of the mounting plate should therefore be bent up as shown in figures.

The mounting plate should be designed so that the contact pressure on the auxiliary frame is distributed evenly onto at least four support surfaces. 26:4121

To avoid damage to the chassis frame, Moveable fifth wheel bridge-piece the end surfaces of the mounting plate should be secured in accordance with must be rounded or bent up. the manufacturers instructions.

10 © Scania CV 2002 Tractors, fifth wheels 4

LOCKING FIFTH WHEEL AND MOUNTING PLATE At the factory fifth wheels are mounted on the mounting plate using special bolts dacroment, tightened to a specific torque. If the fifth wheel is loosened from the mounting plate new M16 8.8 bolts and welded stops should be fitted. The mounting plate is mounted on the angle brackets using four M18 and four M20 tight-fit bolts.

NOTE the mounting plate for 3.5" fifth wheels is mounted using eight M20 tight-fit bolts + four welded stops. 26:4122

NOTE the mounting plate for 3.5" fifth wheels is attached as set out above.

RETROFITTING ANGLE BRACKETS Angle brackets should be attached to the webs of If angle brackets higher than 40 mm are the chassis frame using rivets or bolted joints. The fitted, cross members should be used be- number of bolts depends on the length of the angle tween the angle brackets in order to dis- bracket. As a rule, it is necessary to use at least 10 tribute lateral forces from the semi-trailer. bolts. Use M14 bolts. When retrofitting we recommend that the fifth wheel is secured on the mounting plate by welded stops and the mounting plate is secured to the On 4x2, the angle brackets may not be chassis by using either four M18 and four tight-fit above the chassis frame, as the shape of the bolts or eight M18 bolts and welded stops. angle bracket makes it too weak to carry the load from the fifth wheel on its own.

REINFORCING FOR 6x4 TRACTORS WITH ANGLE BRACKETS When driving on winding roads with high bogie loads, it may sometimes be necessary to provide reinforcement with a cross as illustrated, in order to prevent damage to "cross" members or retroac- tively if damage has occurred to cross members.

Steel rod 70 x 10 mm.

M16 tight-fit bolts

Do not weld the cross, only use straps to eliminate noise.

12 © Scania CV 2002 Tractors, fifth wheels 4

SELECTING ANGLE BRACKET OR AUXILIARY FRAME This choice is made based on the semi-trailer load on the chassis, the chassi-class and the driving conditions. ANGLE BRACKETS The angle bracket is standard on chassis designed for tractors and is suitable for long-distance driving and normal gross weights with a D value of up to 152 kN. For heavier loads with 6x4Z and bogie BT300B, a ANGLE BRACKET AUXILIARY fifth wheel with 3.5" kingpin, sturdier angle brack- FRAME ets and mounting plate is available. Having a D value of 260 kN it is recommended for gross train weights of up to 70 tonnes on bad roads and 120 tonnes on good roads. If higher gross train weights are required, an auxiliary frame is recommended. Auxiliary frame example for F958 frame. AUXILIARY FRAME Section Height x width x Min. surface We recommend an auxiliary frame when Scanias type thickness (mm) moment of angle bracket cannot be used. inertia per The auxiliary frame distributes the point load ap- member plied by the fifth wheel and reinforces the chassis l (cm4) X frame. The auxiliary frame raises the fifth wheel, which is often necessary to safeguard adequate U 110x80x8 380 clearance between the semi-trailer and the wheels and/or the rear ends of the chassis. Z 110x80x80x8 380

The dimensions of the auxiliary frame are depend- ent on the load, operating conditions and the space For more general information about auxiliary required. As a general rule, it is advisable to use frame, see Chapter 2. auxiliary frame dimensions with a minimum surface moment of inertia as in the table opposite, when kingpin loads are high or operating conditions difficult.

The auxiliary frame should consist of open Z or U sections.

Lateral forces from the trailer when cornering should be distributed between the chassis frame members. If lateral forces are applied to one frame member only, this may become twisted and bent. For this reason, the auxiliary frame should be fitted with cross members in front of and behind the fifth wheel mounting points.

For heavy transport with high a total vehicle weight, the auxiliary frame should be provided with several thick cross members forward of and behind the fifth wheel mounting points. 4118

Cross members should be used forward of and behind the fifth wheel mounting points.

Example of auxiliary frame for fifth wheel mounting.

14 © Scania CV 2002 Tractors, fifth wheels 4 26:4105

Heavy tractor

The length of the front part of the auxiliary frame can be significant in preventing chassis frame vibration. An auxiliary frame which extends far forwards makes the chassis frame rigid at this point. The natural frequency of the chassis is raised, which generally means that vibration occurs at road speeds higher than those at which the truck is normally driven. Whether or not the auxiliary frame should be extended forwards must be determined from case to case. As the wheelbase increases, it is more necessary to extend the auxiliary frame forwards. 26:4100

If the auxiliary frame is extended forwards as shown by the dashed line in the illustration, the front section of the auxiliary frame should be bent outwards so that it follows the chassis frame.

16 © Scania CV 2002 Tractors, fifth wheels 4

TYPES OF FIFTH WHEEL Different types of fifth wheel with special characteristics are available to suit a variety of haulage tasks.

2" kingpin The standard type of fifth wheel has a 2" diameter kingpin and is usually rubber-mounted to allow a certain amount of angling. The 2" diameter kingpin is used for kingpin loads up to 20 tonnes.

3.5" kingpin A fifth wheel with a 3.5" kingpin is usually em- ployed for kingpin loads in excess of 20 tonnes and is mainly intended for heavy special transport.

Universally jointed A universally jointed fifth wheel is often fitted if the vehicle is used under difficult conditions, with large angular differential movement between tractor and semi-trailer.

This type of fifth wheel allows for large angular movement both laterally and longitudinally. A universally jointed fifth wheel normally has a kingpin diameter of 3.5".

Replaceable locking mechanism A fifth wheel with a replaceable locking mechanism can accommodate both 2" and 3.5" kingpins to meet different transport requirements.

Moveable A moveable fifth wheel can be fitted, for maximum utilisation of the tractor, particularly in international haulage work.

A moveable fifth wheel enables the rig to be ad- justed to suit various national regulations concerning axle loads and vehicle lengths.

It also allows improved weight distribution between the front and rear axles, and enables adapta- tion to different types of semi-trailer. 26:4109

Raisable and lowerable fifth wheel A raisable and lowerable fifth wheel makes it possible to use a low construction tractor, even with conventional trailers. 26:4131

18 © Scania CV 2002 Tractors, fifth wheels 4

FACTORY FITTED FIFTH WHEELS FROM SCANIA Fixed fifth wheels: Manufacturer Model Material D- value U- value kN kg VBG 2" VBG 150SP 148 pressed steel 150 20 000 GF 2" SK-S36.20 150 cast iron 152 20 000 GF 2" SK-S36.20 W 150 cast iron 152 20 000 Jost 2" JSK 37 C W 150 cast iron 152 20 000 Jost 2" JSK 37 C Z 150 cast iron 152 20 000 GF 2" SK-36.20 185 cast iron 152 20 000 GF 2" SK-36.20 W 185 cast iron 152 20 000 Jost 2" JSK 37 C Z 185 cast iron 152 20 000 Jost 2" JSK 37 C W 185 cast iron 152 20 000 Jost 2" JSK 37E 185 cast iron 152 20 000 Jost 2" JSK 36DV17G 205 pressed steel 152 20 000 VBG 2" VBG 150SP 210 pressed steel 150 20 000 BigD 2" YF 224201 244 pressed steel 150 20 000 Jost 2" JSK 37 C Z 250 cast iron 152 20 000 Jost 3.5" JSK 38 C-1 3.5/190 cast iron 260 36 000 Jost 3.5" JSK 38 G-1 3.5/290 cast iron 260 36 000

D-value = theoretical horizontal force U-value = max vertical imposed load Fixed fifth wheels with mounting plates 22 and 40 mm Manufacturer Model D- value U- value With 22 mm With 40 mm mounting plate mounting plate kN kg Height Weight Height Weight VBG 2" VBG 150SP 150 20 000 170 165 - - GF 2" SK-S36.20 152 20 000 172 169 190 171 GF 2" SK-S36.20 W 152 20 000 172 169 190 171 Jost 2" JSK 37 C W 152 20 000 172 195 190 198 Jost 2" JSK 37 C Z 152 20 000 172 187 190 190 GF 2" SK-36.20 152 20 000 207 173 225 175 GF 2" SK-36.20 W 152 20 000 - - 225 175 Jost 2" JSK 37 C Z 152 20 000 207 194 225 197 Jost 2" JSK 37 C W 152 20 000 - - 225 202 Jost 2" JSK 37E 152 20 000 - - 225 183 Jost 2" JSK 36DV17G 152 20 000 227 174 245 177 VBG 2" VBG 150SP 150 20 000 232 173 250 177 BigD 2" YF 224201 150 20 000 246 170 - - Jost 2" JSK 37 C Z 152 20 000 272 207 290 210 Jost 3.5" JSK 38 C-1 260 36 000 - - 230 277 Jost 3.5" JSK 38 G-1 260 36 000 - - 330 352

Sliding fifth wheels: Manufacturer Model Height Material D- value U- value Weight Sliding distance mm kN Kg Kg step total Jost EVDM0000206 171 Pressat stål 152 20 000 222 13x50.8 660 Jost EVDVM 2-10 209 Pressat stål 133 18 000 288 15x39 585 VBG (not 4x2) VBG 135SF 245 Pressat stål 135 18 000 283 14x37.5 525 BigD YF A201 260 Pressat stål 150 20 000 266 6x75 450 Jost EVDVM 1-01 263 Pressat stål 133 18 000 283 12x39 468 VBG (only 4x2) VBG 135SF 265 Pressat stål 135 18 000 246 14x37.5 525

Calculating the D-value for tractors with semi-trailers

D = g x 0,6 x T x R ( kN ) T + R - U

U 26:4148

T R

T = Technically permitted overall weight in tonnes for the tractor. R = Technically permitted overall weight in tonnes for the semi-trailer. U =Vertical load in tonnes on the fifth wheel. g = 9,81 m/ s2

20 © Scania CV 2002 Tractors, fifth wheels 4

Factory fitted angle brackets for different types of chassis 95 26:4134

4x2 A/B

95 26:4138

4x2/4x4 Z

Factory-fitted angle brackets on two-axle tractors are level with the chassis frame. On three-axle tractors they are mounted so that they protrude 40 mm above the chassis frame. 40 26:4136

6x2/6x4 A/B

40 26:4137

6x2/4 A/B

40 F958 32 F950 26:4139

6x2 Z

40 26:4140

6x4 Z

Factory fitted moveable fifth wheels

A = Moveable range.

660 A

209

CL 26:4141

A 4x2 and 4x4 with Jost EVDVM 2-10 A = 585 mm

6x4Z BT201 150 6x4 A/B 140 6x2A/B/Z 90 A

249

CL CL 4142

A 6x2 and 6x4 with Jost EVDVM 2-10 A = 585 mm

A = Moveable range. 728 Ad 3300 666 Ad 3550 660 Ad 3700, 3900 A

A 4x2 and 4x4 263 with Jost EVDVM 1-01 A = 468 mm 4143 CL

1093 A

303 A 6x2/4 with Jost EVDVM 1-01 4144 A = 468 mm CL

6x4A/B 82 6x2A/B 30 A

303 A 6x2 A/B and 6x4 A/B with Jost EVDVM 1-01 CL CL 4145 A = 468 mm

635 Ad 3300 A = Moveable range. 735 Ad 3550, 3700 A

A 4x2 and 4x4 265 CL with VBG 135 SF

4146 A = 525 mm

1160 Ad 3975 1210 Ad 4100 A A 6x2/4 285 with VBG 135 SF

4147 A = 525 mm CL

65 A

285 A 6x2 A/B and 6x4 A/B CL CL with VBG 135 SF 26:4148 A = 525 mm

A = Moveable range. 635 Ad 3300 735 Ad 3550, 3700, 3900 A

A 4x2 and 4x4 260 with BigD YF A201

A = 450 mm 4149 CL

1160 Ad 3975 1210 Ad 4100 A

A 6x2/4 300 with BigD YF A201 4150 A = 450 mm CL

65 A

300 A 6x2 A/B and 6x4 A/B with BigD YF A201 CL CL 4151 A = 450 mm

762 A = Moveable range. A

171 A 4x2 and 4x4

4152 with Jost EVDM 0000206 CL A = 660 mm

1139 A

211 A 6x2/4 with Jost EVDM 0000206 4153 CL A = 660 mm

38 A

211 A 6x2 A/B and 6x4 A/B CL CL with Jost EVDM 0000206 4154 A = 660 mm