ST Engineering EHS Award 2008 - Safety

1. ST Engineering EHS Award 2008 - Safety Improved Process for Assembly of Rebound Stopper For Bronco Vehicle

2. TEAM (EA MOBILITY) LEADER: Phang Seng Keong (Process Engineer) MEMBERS: Leonard Lee (Process Engineer) Willy Goh Beng Lip (Process Engineer) Francis Sim Mong (Process Engineer) B Thritraj (Senior Foreman) Lim Hock Beng (Senior Technician) Facilitator : Geoy Meng Chye (Process Engineer) Safety Advisor : Michael Leong

3. SAFETY PROJECT Improved Process for Rebound Stopper Assembly For Bronco

4. INTRODUCTION • Kinetics Integrated Manufacturing is a Business Unit within ST Kinetics, primarily responsible for manufacturing weapons and platform solutions. • Mobility Systems (MS) Operations, Manufacturing Engineering (ME) Department is primarily responsible to ensure transfer of engineering designs to workshops, by designing the manufacturing process and required supporting elements.

5. INTRODUCTION • The Bronco vehicle is one of the most successful products from ST Kinetics, producing in large quantities. • During the annual HIRARC review, it was noted that for the Flatbed variant, the process posed a hazard to the 4 crewmen involved. (image of flatbed variant)

6. CURRENT SITUATION Dead weight Rebound Stopper A 3- Ton weight is being use to compress and open up the last wheel to install the rebound stopper. Idler Wheel Accident happen if there is no proper co-ordination. Eg. Crushing of hands and fingers.

7. CURRENT SITUATION 1 Track are slipped onto the track beam 4 The Bumper Stopper is then mounted 2 The flatbed is lifted and the aluminium block is positioned under the idler wheel 3 The external weight is lifted and lowered to stretched the idler wheel

8. Risk Assessment (Old)

9. Risk Assessment (Old)

10. Risk Assessment (Old)

11. Ideas on trial. Brackets • Ideas on trial • We had tried a pushing method, What it meant was pushing the idler wheel backwards • The problem face, there wasn’t a fixed position for us to push against. The road wheels was being push forward. Rotating the lead screw will make the bracket move closer or further apart Road Wheel Idler Wheel • Ideas on trial • The idea came about why not pull. • A 3 ton chain block was used. • The setup is shown. • It works but the track needed to be considered. • NOW WE NEED A STRONG PULL FORCE.

12. Solution Criteria • Design Problem: • How to extend the track sufficiently to allow for space to in stall the rebound stopper • Design Consideration • To move the last idler wheel by 16inch from the collapse position to the extended position. • Upon stressing the torsion rubber, every degree we have an increase of 78kg. We require a force of 40000N (4000kg) to rotate to the correct position of 52 degrees. • Availability of standard equipment to rotate the last road wheel : Chain block 5tons, Wire rope winch 3.5tons and Hydraulic pull cylinder.

13. 3 ton chain block • The chain block is insufficient to overcome the 40000N. • This consideration was dropped • 5 ton chain block • The chain block can provide a 50000N force to overcome the torsion rubber. • Base on HFE, the recommended weight for 1 person to handle should be less then 20 kg. The chain block weighs 30kg. • There was space constraint between the track beam and track • This consideration was dropped The chain block was the most obvious solution to be tested. Unfortunately it came with serious constraints that cannot be overlooked. Hence the team proceeded to find other alternatives.

14. ur • 3.5 ton wire rope winch • The Winch was thin enough to fit into the space constraint between the track beam and the track. • It serves the purpose of pulling action • The Winch is insufficient to overcome the 40000N. There was no 5 ton and above winches • This consideration was dropped

15. Pull Hydraulic cylinder 3.5tons • The Cylinder was compact enough to fit into the space constraint between the track beam and the track. • It serves the purpose of pulling action • The cylinder is insufficient to overcome the 40000N. • This consideration was dropped

16. Considerations • There are no standard tooling or fixtures that is available in the market to have a pulling force of more then 40000N • The standard tooling or fixture should be lighter then 20kg and compact in size • And of course low in cost. • Available standard parts are hydraulic cylinder which has a rating of 10ton but they only come as push cylinder. • The team had to iterate the pushing action of the hydraulic cylinder to pulling action

17. Center Bar when hydraulic jack is extended will move to the left A fixture was needed to reverse pushing to a pulling MS SQ Hollow 63.5X63.5x6.35thk From the last proposed solution, the team refined the concept to come up with an in-house design. 10ton Hydraulic Cylinder Dia 25mm Steel Shaft

18. New Method Illustration Straps attached to the front bracket and rear road wheel B A Upon extending the jack the 2 bars A and B will move closer together and thus pulling the road wheel up

19. New Method Illustration The jig being activated and the last road wheel is pull to the required gap to install the Rebound Stopper.

20. Sequence of installation

21. Enhance Safety For New Method There were other safety consideration, There was a hazard that the cylinder will fail and the idler wheel will swing back, This might happen when we are installing the bumper stop. Insert the 2 X M10 screws to its mounting as shown to mitigate the injuries if sling snaps and road wheel swings down. Primary safety feature: Insertion of 2 x M10 screws will prevent any wrist injury should the last road wheel swing down.

22. Enhance Safety For New Method Place Rect-frame at extension square bracket. Rectangular Frame Secondary safety feature: The rectangular frame to prevent the separation of the 2 pulling belts at the hydraulic fixture.

23. Enhance Safety For New Method Place Pump Cover at Hydraulic Air Pump Added secondary safety feature: The pump cover will prevent the worker hand from accidentally activating the pump. Hydraulic Air Pump

24. Evaluation of solution: • The new solution has been evaluated and the benefits are: • The risks of human injury and property were found to have significantly reduced compared to the earlier method when evaluated by the HIRARC criteria. • The crew size can be reduced from 4 to 2 thereby reducing risk exposure. • The space required has been reduce, hence reducing risk of affecting adjacent workspace. • The solution has been implemented for the remaining vehicles under production. We have updated our work instructions with this process to become SOP

25. Risk Assessment (New)

26. CONCLUSION • Able to eliminate the risk of hand injuries through innovative redesigning of the process • Improve the safety environment for the operation crews. • Team gained greater safety awareness and able to focus more on safety aspects when designing processes in future.