tow trucks (design) 8€¦ · an accredited t1 ave in construction, inspection and certification of...

Contents

Section T — Overview 2 1. Description 2 2. Related Australian Design Rules 2 3. Tow truck types 2 5. Record keeping 2 6. Design requirements 2

Modification Code T1 — Tow trucks (construction) 3 1. Scope 3 2. Related standards 3 3. Certification procedure 3 4. Compliance requirements 3 5. Design requirements 3 6. Installation requirements 4 7. Testing requirements 4 T1 Checklist — Construction of tow trucks (example) 5

Modification Code T2 — Tow trucks (design) 8 1. Scope 8 2. Related standards 8 3. Certification procedure 8 4. Compliance requirements 8 5. Design requirements 8 T2 Checklist — Design of tow trucks (example) 10

Vehicle Standards Bulletin 6 — Version 3.1 Section T — Tow trucks 2 of 10

Section T — Overview 1. Description This section of Vehicle Standards Bulletin 6 (VSB6) relates to construction and design of tow trucks which are based on a suitable truck chassis. The section outlines minimum design, installation and performance requirements for fitting the vehicle towing systems of tow trucks, including lift trucks and tilt tray trucks.

This section consists of the following modification codes: T1 Construction of tow trucks

• construction of tow trucks according to a certified design • modification or replacement of tow truck components

other than lifting components • replacement of tow truck lifting components.

T2 Design of tow trucks • certification of a tow truck design • rating of lifting/towing components • testing/certifying of lifting of towing components.

2. Related Australian Design Rules The Australian Design Rules (ADRs) relevant to this section include: ADR no. Title 13/.. Installation of Lighting and Light-signalling

Devices on other than L-Group Vehicles 42/.. General Safety Requirements 43/.. Vehicle Configuration & Dimensions 44/.. Specific Purpose Vehicle Requirements 62/.. Mechanical Connections Between Vehicles

3. Tow truck types Three types of tow trucks in common use are described below. Each type can be combined in various ways but the vehicle must meet applicable standards, mass and dimension requirements. Overlift type: a crane type vehicle towing system that lifts the front or rear axles of the vehicle to be towed and secures it in position with a towing hitch.

Figure 1: Overlift type tow truck

Underlift type: has an arm that extends underneath the towed vehicle that lifts the towed vehicle by wheels, chassis or other suitable part.

Figure 2: Underlift type tow truck

Tilt and slide tray type: has a tray body that can be moved back and tilted so that the rear end of the tray rests on the ground. The towed vehicle is winched up onto the tray and secured. The tray is then raised onto the truck chassis for travel.

Figure 3: Tilt and slide tray type tow truck

Tow truck classes applying to the above types are defined in ADR44/.. and further categorised in regulation by the jurisdictional registering authority.

5. Record keeping The person responsible for certifying the modification should:

• collate complete records, including drawings, calculations, test results and copies of the appropriate issue of Australian Standards and ADRs

• retain the records for a minimum of seven years after commissioning of the modified vehicle

• make the records available upon request for inspection by officers of the relevant federal, state or territory authority or relevant heavy vehicle regulator.

Reports and checklists The person responsible for certifying the modification must complete and record the following reports and checklists as applicable: T1 Checklist Construction of tow trucks T2 Checklist Design of tow trucks

Engineering analysis necessary in the course of designing a safe tow truck may be much more than what is specified in this section. The certifying approved vehicle examiner (AVE) is required to assess the design and the level of analysis required.

6. Design requirements Advanced braking systems Advanced braking systems are an important safety feature fitted to many new vehicles. Advanced braking systems are programmed by the vehicle manufacturer and are specific to the vehicle to which they are fitted. Changes made to the vehicle, such as engine, tyre size, steering control, suspension characteristics, vehicle mass and its distribution, may impact the performance of the advanced braking system. Exercise extra caution when modifying vehicles fitted with advanced braking systems. Electric braking systems may be known as: • electronic stability control (ESC) • electronic stability program (ESP) • vehicle stability control (VSC) • dynamic stability control (DSC) • vehicle stability assist (VSA) • roll stability control (RSC) • roll control system (RCS) • electronic braking system (EBS) • trailer electronic braking system (TEBS).

Advanced braking systems and their components may be easily damaged by common modification, maintenance and servicing techniques, such as the use of rattle guns within one metre of the sensors. When undertaking any work on a vehicle fitted with an advanced braking system, ensure all modifiers are familiar with these systems and the precautions that must be taken.

Ensure that before undertaking any modification on a vehicle that is fitted with an advanced braking system the modifier and AVE consult with the vehicle manufacturer to determine the impact on the system.


Modification Code T1 — Tow trucks (construction)

1. Scope Modifications covered under this code:

Covered • construction of tow trucks according to a design certified in

accordance with VSB6 Modification Code T2 • modification or replacement of tow truck components other

than lifting components • replacement of tow truck lifting components.

Not covered • cutting, extending or reinforcing the chassis (see VSB6 Section H

— Chassis) • construction of tow trucks that are not constructed according to

a design certified in accordance with VSB6 Modification Code T2 • repositioning or adding any vehicle components that are not

compatible with the vehicle or may cause it to be non-compliant with ADRs or in-service vehicle standards, mass, dimension or loading requirements

• modifications or structural repairs to lifting components.

2. Related standards Modified vehicles must comply with all ADRs, Australian Standards, acts and regulations. Below are some but not all of the areas that may be affected by the modifications in this code and require certification testing or evidence to demonstrate compliance.

The certifier must ensure that the modified vehicle continues to comply with all related ADRs.

This… Must comply with… Rear axle/s installation VSB6 Modification Code D1 Chassis alteration VSB6 Modification Code H4 Remounting of body VSB6 Modification Code J1 Tow couplings VSB6 Modification Code P1 Truck loading cranes VSB6 Modification Code R1

The certifier must ensure that the modified vehicle continues to comply with the following Australian Standards:

• AS 1418.1 Cranes – General Requirements • AS 1418.2 Cranes (including hoists and winches) – Serial hoists

and winches • AS 1418.5 Cranes, hoists and winches – Mobile cranes • AS 1418.11 Cranes, hoists and winches – Vehicle-loading cranes • AS 5400 Tow Trucks – Tilt, slide and underlift vehicles.

3. Certification procedure The certification procedure for this modification code is as follows:

1. Modifier Determine if the tow truck design is certified in accordance with VSB6 Modification Code T2. • If yes, perform modification in accordance with T2

certified design instructions and requirements; proceed to step 3.

• If no, proceed to step 2. 2. Modifier Contact accredited T2 AVE to:

• supply a certified design; or • create T2 to certification for the existing tow truck

design. Refer to T2 certification procedure. Return to step 1.

3. Modifier Consult with an accredited T1 AVE for guidance on how to perform the modification.

4. Modifier Perform modification in accordance with AVE advice, the T2 certification and this code.

5. Modifier Organise approval inspection by an accredited T1 AVE.

6. T1 AVE Perform inspection, complete T1 checklist and determine if compliance has been achieved. • If yes, proceed to step 7. • If no, do not proceed, advise modifier rework is

required to ensure compliance. Return to step 3. 7. T1 AVE Issue modification certificate, affix modification

plate, and submit paperwork as required by the relevant AVE registration scheme.

AVEs must be satisfied that the vehicle modification requirements are being met. It is advised that before modifications are carried out they are discussed with the certifying AVE.

4. Compliance requirements As there are no recognised international standards for towing equipment, it cannot be assumed that imported equipment will meet relevant requirements. A reduction in rated capacities is likely.

Required: • Ensure the accredited T1 AVE inspecting and certifying the

construction obtains, uses and retains the T2 certificate and checklist.

• The certification verifies that all components meet the requirements for the class of tow truck and that the finished vehicle meets VSB6 Modification Code T2 requirements.

• Ensure components, and their mounting, meet the requirements for the class of tow truck (as defined in ADR 44/..) and certified in accordance with VSB6 Section R — Vehicle mounted lifting systems and this code. • Ensure the operator of the tow truck retains a copy of the T2

certificate and checklist and the T1 certificate and checklist.

5. Design requirements

Required: • Ensure the design of any new tow truck is certified by an

accredited T2 AVE. • Ensure the design considers and establishes a safe working load

(SWL) that meets or exceeds stability testing requirements. • Ensure that any alterations to an existing vehicle that would

affect the original design certification are re-certified by an AVE. • Ensure that all cranes and other lifting equipment that form part

of the tow truck comply with the relevant sections of AS 1418.5 Cranes, hoists and winches – Mobile cranes.

Modification Code T1


6. Installation requirements Installation requirements are addressed in AS 1418 Part 1-5, 11 and AS5400. Requirements for mobile cranes, including tow trucks, are addressed in AS 1418 Part 5, AS 1418 Part 11 and AS5400.

Required: • Ensure installation is done in accordance with the Certified T2

design. • Ensure the documentation package for the T2 certified design

includes the T2 certificate and checklist for retention and use by an accredited T1 AVE in construction, inspection and certification of a tow truck.

• Ensure lifting equipment that is being installed is rated by the manufacturer for the application and complies with AS1418.

• Ensure the installation method complies with the vehicle manufacturer’s recommendations and has sufficient chassis reinforcement to maintain the lift induced load moment, within the chassis design limits (see VSB6 Modification Code H4).

• Ensure the completed vehicle complies with all regulations concerning mass, dimensions, general safety requirements (specifically ADR 42/.. and in-service heavy vehicle mass and dimension regulations).

• Ensure the crane and related modifications comply with all other relevant sections of VSB6.

7. Testing requirements

Stability test • Test and evaluate fully any new and previously untested lifting

equipment and retain all calculations, test reports and other evidence of testing.

• Conduct stability tests to ensure that the vehicle is capable of being safely controlled while towing, on Class 1 4 lift and tow trucks (Classes as defined in ADR 44/.. ).

Required: • Ensure the SWL calculated is less than the maximum allowed by

the crane/vehicle towing system manufacturer in that position, but not less than the minimum requirements for the relevant tow truck class.

• Where a test weight is not available, the tow truck owner supplies the test load.

• For slewing cranes, conduct tests as for the stability tests for truck mounted cranes (see VSB6 Section R — Vehicle mounted lifting systems).

Recommended: • Ensure the tow truck is capable of being controlled safely at low

speed when the lifting gear is subject to a 25% overload.

Calculations that establish the SWL are a requirement of the T2 certification process. The formula required to perform these calculations can be found in VSB6 Modification Code T2.



T1 Checklist — Construction of tow trucks (example)


Modification Code T2 — Tow trucks (design)

1. Scope Modifications covered under this code:

Covered • certifying of tow truck design • rating of vehicle lifting/towing components • testing and certifying of vehicle lifting/towing components

Not covered • rating of any components beyond the manufacturer’s

specifications • construction and inspection of a tow truck (see VSB6

Modification Code T1).

2. Related standards Modified vehicles must comply with all ADRs, Australian Standards, acts and regulations. Below are some but not all of the areas that may be affected by the modifications in this code and require certification testing or evidence to demonstrate compliance.

The certifier must ensure that the modified vehicle continues to comply with all related ADRs.

This… Must comply with… Rear axle/s installation

VSB6 Modification Code D1

Chassis alteration VSB6 Modification Code H4 Remounting of body VSB6 Modification Code J1 Tow couplings VSB6 Modification Code P1

ADR 62/.. Truck loading cranes VSB6 Modification Code R1

AS 1418 Class of tow truck ADR 44/..

3. Certification procedure The certification procedure for this modification code is as follows:

1. Modifier Contact appropriately qualified and accredited T2 AVE to supply vehicle and lifting equipment specifications or organise vehicle inspection by an accredited T2 AVE.

2. T2 AVE Assess and provide design certification to modifier listing specifications, equipment and installation instructions.

3. Modifier Consult with an accredited T2 AVE for guidance on what modifications are required.

4. Modifier Consult with an AVE who is accredited to certify each modification for guidance on how any modification is required to be performed. Follow the certification procedure in each applicable modification code. For example, where the chassis requires reinforcement, refer to an accredited H4 AVE and VSB6 Modification Code H4.

5. Modifier Organise approval inspection by an accredited T1 AVE.

6. T1 AVE Perform inspection, ensure all modifications and equipment have been certified (if applicable), complete T1 checklist and determine if compliance has been achieved. • If yes, proceed to step 7. • If no, do not proceed, advise modifier rework is

required to ensure compliance. Return to step 4. 7. T1 AVE Issue modification certificate, affix modification

plate and submit paperwork as required by the relevant AVE registration scheme.

AVEs must be satisfied that the vehicle modification requirements are being met. It is advised that before modifications are carried out they are discussed with the certifying AVE.

4. Compliance requirements As there are no recognised international standards for towing equipment, imported equipment will not automatically correspond with relevant Australian regulations. Imported equipment will need to be assessed, and possibly re-rated, in accordance with Australian regulations by a professional engineer registered with a professional registration body.

The design certification requirements for tow trucks are as follows:

Required: • Ensure the T2 certification documentation package provided for

the T1 certifying AVE and vehicle operator includes requirements or instructions for mounting and installing tow truck equipment.

• Ensure the mounting of each of the components meets the requirements for that particular class of tow truck (see ADR44/.. for tow truck classes).

• Ensure the crane fitting complies with all applicable regulations including AS1418 and AS5400.

• Ensure truck towing equipment is compatible in terms of lifting and carrying capacities and is stable for normal road travel.

• If the design of the tow truck involves use of more than one make/model of a major component (i.e. crane), ensure it is approved for all possible combinations or options.

5. Design requirements

Required: • Ensure the design considers and establishes a safe working load

(SWL) that meets or exceeds stability testing requirements. • Ensure the accredited T2 AVE assesses the design and the level of

engineering required. The accredited T2 AVE needs to also obtain and retain copies of any additional engineering assessments or related designs.

• Ensure the completed vehicle complies with all regulations concerning mass, dimensions and general safety requirements (specifically ADR 42/.. ).

• Where components used have been certified as compliant with the relevant Australian Standard by the component manufacturer, ensure that the installation, mounting and capacities of the components are applicable for that class of tow truck and certified in accordance with this code.



Safe working loads

Required: • Ensure the SWL calculated is less than the maximum allowed by

the crane/vehicle towing system manufacturer in each position, but not less than minimum requirements for the relevant tow truck class.

• Ensure the tow truck is capable of being controlled safely at low speed when the lifting gear is subject to a 25% overload.

• Where a test weight is not available, the tow truck owner supplies the test load.

• For slewing cranes, conduct stability tests as for truck mounted cranes (see VSB6 Section R — Vehicle mounted lifting systems).

Calculations for determining safe working loads As the vehicle lift is situated behind the rear axles, the tow truck’s centre of gravity will move back considerably when a load is lifted. As modern tow trucks could have a lifting capacity in excess of what the truck is permitted to tow, perform the following calculations to determine safe working loads (SWL) for towing.

The lifting point is the centre of where the vehicle towing system lifts the towed vehicle. In the case of wheel-lifts for example, it is the centre of the wheels lifted.

Overlifts

Calculate SWL for overlifts using this formula:

𝑆𝑆𝑆𝑆𝑆𝑆 = 0.6 × 𝑇𝑇 ×𝑆𝑆𝑊𝑊

𝑂𝑂𝑂𝑂

Where: 0.6 = a constant meaning 60% of T can be used as a

counterweight T = tare weight of front axle WB = wheelbase of tow truck OH = rear overhang measured from pivot point F = SWL

Figure 4: Overlift tow truck weight distribution calculation

Underlifts Because underlifts can carry their loads at different positions, calculate SWL for underlifts using the same formula for overlifts for the worst case loading:

𝑆𝑆𝑆𝑆𝑆𝑆 = 0.6 × 𝑇𝑇 ×𝑆𝑆𝑊𝑊

𝑂𝑂𝑂𝑂

This is likely to be one or more of the following three positions: 1. With lifting boom

fully retracted.

2. With lifting boom

halfway between fully retracted and fully extended.

3. With lifting boom

fully extended.

Figure 5: Underlift tow truck weight distribution



T2 Checklist — Design of tow trucks (example)

tow trucks (design) 8€¦ · an accredited t1 ave in construction, inspection and certification of...

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