Tuesday, March 27, 2007
Monday, March 26, 2007
Friday, March 23, 2007
Q: An individual involved in a rollover accident in a "3 class BMW convertible" relayed that after the accident, there were two tubes sticking up from each seat, acting as roll bars, that were not exposed when first arrived at the scene. Has anyone heard of such a hidden roll bar system? Would this be a potential hazard to rescue personnel similar to non-deployed airbags?
A: There are currently two types of automatic roll-bars (RPS/ROPS). A pop-up model that is mounted behind the occupant seat and a second type that flips up to look much like a conventional flat roll-bar. These have been on the production line for some time, but with little publicity until now.
BMW Rollover Protection System (RPS) that you are asking about can be seen on the BMW E36 Convertible. This is a spring loaded unit which is mounted directly behind each rear seat headrest. Unlike Volvo and BMW, which are using a mechanical spring loaded deployment, both Mercedes pop-up and flip-up systems are hydraulically deployed. The Mercedes pop-up system has a single bar with two "U" shaped bends which extend up through two openings. The Volvo and BMW are two separate cassettes.
The RPS/ROPS is activated by an inclinometer to sense vehicle inclination and lateral acceleration. There is a G-sensor to sense vehicle weightlessness also.
The system will deploy when the control module senses any of the following:
- When the vehicle approaches a lateral angle limit of 62 degrees.
- When the vehicle experiences a lateral acceleration of approximately 3 Gs.
- When the vehicle approaches its longitudinal angle limit at approximately 72 degrees.
- When a combination of longitudinal acceleration and longitudinal angle would cause the vehicle to roll over in the forward direction.
- When the vehicle becomes airborne and achieves weightlessness for at least 80ms.
The control module senses the above (except for weightlessness) by means of the inclinometer built into the control unit. If the vehicle is tilted or accelerated enough, the air bubbles in one of the tubes in the inclinometer pass by a LED. A photo transistor mounted across from the LED senses a change in density of the liquid when the bubble crosses the beam. It then sends a signal to the processing chip. The Volvo/BMW control unit will then send a signal to the actuator solenoids on each of the two separate cassettes. This releases the restraining catches and the roll bars will spring upward.
As with the SRS, the backup power supply capacitors allow the system to function even if the vehicle power is interrupted in an accident. The Volvo RPS has a reserve power unit which will store a charge for 5 seconds.
Both types of RPS will deploy between 2 and 3 tenths of a second!! Once the sensor in the vehicle predicts the car to be in a rollover situation, the bars will deploy. They may also be deployed by the driver (Mercedes) using a manual switch on the dash. The RBS may also be interconnected to the airbag system. De-energize the electrical system as soon as possible, including any device such as GPS, cell phones and alarm systems which may back feed the SRS.
A dangerous point to remember is that they look harmless and blend in with the interior of the car's color scheme. Perhaps the best way to avoid injury to a rescue worker is to manually deploy the roll-bar in a controlled situation. Mercedes' have an electric switch which can slowly (approximately 4 seconds) raise or lower the roll-bar. The Volvo mechanics that have been trained in the system can manually deployed the roll-bar using a long handed straight screw driver. The BMW can be activated by a tester or MoDiC; there is an access hole for trained personnel to manually activate the system.
Some systems can be locked out using a computer. When transported the Volvo convertible ROPS is deactivated at the factory, the dealer uses a computer to reactivate the system.
For rescuer holding traction for a C-spine injury, the rescuer would normally assume a position behind the patient. This now put the path of deployment in the neck head area of the rescuer! I measured the distance for a Mercedes and that was approximately 10 inches from the deck to the top of the pop-up roll bar, the Volvo roll-bar extends 20 inches - once deployed they have to be manually reset, this will allow you to safely work behind the patient. When in doubt if the bar has been deployed, keep a proper safe working distance. This goes for any supplemental restraint device.
The pop-up type has a protective plastic cap that snaps on a "U" shaped bar. The flip-up type is padded and folds down to wrap around the rear deck. It blends in perfectly and you might assume it to be just part of the plastic trim to the fabric top.
I have co-authored an emergency guideline for airbags and automatic roll-bars to be used for rescue personnel. IT was published on the Internet by Emergency Grapevine Magazine. You may find it by going to the following link:
There will be a picture of a Mercedes CLK with the pop-up type roll-bars. Your local dear for BMW, Volvo and Mercedes should be more than happy to show you these new devices and perhaps deploy them. Specific information on RPS/ROPS is available in technical references from the manufactures.
As we make safer cars for the occupant, we also increase the risk to emergency service personnel. If you don't have a dealer near by I will be glad to send you a jpg of both types of automatic roll-bars.
Tuesday, March 20, 2007
Easily installed - precalibrated remote sensor box installs with 2 screws!
Operator Friendly - maintenance free & simple to use
Reliability - superior reliability over any other boom angle indicators
Shut-off Ready - optional switch outputs to shut-off solenoids or activate an external alarm or lamp
Built Rugged - reliable operation through weather and usage extremesCost Effective - ensured quality while saving time and money
Monday, March 19, 2007
Excavators where the digging action is a downward arch motion are known as backhoes or hoes and even back shovels. Thus they are used to excavate below the ground surface or below the machine track level.
Picture of a crawler track backhoe
Back hoes beside being mounted on crawler tracks can also be mounted on a wheel base. Wheel mounted excavators are not specifically for bulk excavation but designed for mobility and general purpose works. The John Deere excavators and JCB excavators are the most well known examples of the wheeled based types. A typical modern back hoe and it's key components are depicted in the diagram below.
A Backhoe Diagram
Uses of back hoes
These machines are suitable for excavating trenches, pits for basement and smaller machines can handle general grading work. It is a versatile machine in that it can perform both excavation and lifting works. Example in drainage works or utility works , the back hoe can perform the trench excavation and handle the pipes or culverts. Thus this makes the need for a second lifting machine unnecessary.
During excavation the penetration force in to the material being excavated is achieved by the stick cylinder and the bucket cylinder. The buckets can be selected depending on the type of material excavated. For easily excavated material wide buckets are used. When excavating rocky material or blasted rocks, a narrow bucket is used. In utility works, the width of the required trench is the deciding factor in selecting the bucket.
Tuesday, March 13, 2007
Factory-Installed Grade Electronics
Caterpillar's E-Series backhoe-loaders (introduced early this year) have the industry's first factory-installed electronics to support an automatic grade-reference system. Product Link and an entry-level AccuGrade system are options. The AccuGrade BHL Site Reference System adds position sensors to the backhoe's hydraulic cylinders and an inclinometer, which allow it to determine the position of the bucket relative to a known reference point, such as a grade stake, on the site. Caterpillar plans to introduce the BHL Laser System before year's end.
Number of models: 3
New models: 416E, 420E and 430E
Product-line features: Cat redesigned the frames, booms, sticks and axles for the E Series, and switched to an exterior-sliding extendable dipper stick. A new flow-sharing hydraulic valve meters oil evenly to all functions even when using several at the same time. Most backhoe forces increased 10 percent on the 420E and 430E.
Accelerometer et al: Relationships between "ball bank indicator" reading, lateral acceleration rates, and vehicular body-roll rates.
Monday, March 12, 2007
BPP Technical Services provides a specialist range of engineering expertise, products and services to the offshore oil and gas industry and to the insurance industry.
"A First in Mooring Position and Integrity Monitoring"
An innovative position and integrity monitoring system has been incorporated into the Chevron ALBA turret moored FSU providing enhanced safety.
Developed by BPP Technical Services Ltd for Single Buoy Moorings Inc., who were responsible for the Bottom Mounted Integral Turret (BMIT) and mooring system, it uses chain angle measurements to determine the turret excursion from the calm water reference position and mooring line integrity.
The BMIT is part of the ALBA Floating Storage Unit (FSU) of approximately 120,000 tonnes dwt moored in the central part of the
The FSU is maintained on location by an array of twelve composite anchor lines. The catenary angle of each chain is measured using an underwater inclinometer mounted on the chain hawse articulation shaft, which has only one degree of freedom. These are monitored by a computer, which uses complex algorithms to derive the BMIT location. This is compared with position information from an Artemis microwave range and bearing unit also forming part of BPP's supply.
The FSU surge oscillations have a period of 100 to 150 seconds and wave periods vary from a few seconds to 17 seconds. The nominal chain angle is 47.5¡ã to the horizontal. A single measure of the mooring system integrity is provided by the amplitude of the FSU excursion, i.e. the offset of the BMIT from its neutral position in the absence of external loads (i.e. loads caused by wind, wave and current). By monitoring the chain angles, it is possible to determine at all times both the excursion and the individual line tensions so that any abnormality can be detected.
Similarly the BMIT position can be monitored using a line-of-sight ranging system, D-GPS or other positioning system to warn of any problems causing unacceptable excursions. In this case the Artemis system is used.
The receiving Artemis antenna mobile station is placed on the radar mast above the FSU control room. The positioning system is equipped with all necessary sensors such that the position of any point on the FSU offset from the receiving antenna can be determined. This is includes roll and pitch sensors mounted near the FSU's pitch and roll centres of rotation to adjust for the FSU movements and relative location of the receiving antenna. The location of the FSU is thus determined relative to ANP on which the fixed Artemis station is located approximately 3km away. The data is further processed to present the position of the BMIT relative to the neutral reference position.
Position and integrity are displayed on dual screens in a variety of formats. The system allows for recovery of long term statistical information and time series gathering which is of benefit in analysing the performance of the FSU and its mooring system, potentially offering data which may be used for improved future designs. The installed system also provides for extensive interfacing with other systems, including alarm reporting and logging, as well as exporting pitch and roll data which may be used in assisting other operations such as with helicopters.
In addition to the above capabilities, the mooring line monitoring system proved of great worth in enabling the installation contractors access to the otherwise unavailable chain angle values to assist in the tensioning of the mooring lines at the time of installation.
It is anticipated that many more of this type of system will see duty throughout the world.
For more information on this subject or related subjects please contact us.
Tuesday, March 06, 2007
Crowley Continues Support of U.S. Navy in Ehime Maru Recovery Project
State and federal laws do not allow for the ship to be left in shallow water or returned to its original location when the Navy's recovery operations are complete. Therefore, upon completion of the recovery effort, Crowley will perform environmental cleanup up of the Ehime Maru as needed, and will support the sealing of the vessel's compartments for relocation to its final resting place. Crowley will also lift and move the vessel from its current shallow water recovery location to its final deep-water resting-place 13 miles off the coast of Hawaii in approximately 6,000 ft. of water.
Phase I of the project, which was handled by the Dutch recovery company SMIT TAK, is now complete. It involved raising the vessel from its original resting-place at a 2,000-foot depth, and transporting it to the shallow water dive site off the coast of Honolulu. Crowley provided transportation support of equipment for SMIT TAK during Phase I, and took over for Phase IIof the project at the new shallow water site in approximately 115 ft. of water about a mile south of Honolulu International Airport.
Crowley's Todd Busch, contracts manager, and Mike Rampolla, project manager, have overseen the Crowley team working on both Phase I and Phase II of the project. So far, approximately 36 Crowley Marine Services personnel have been involved with the project, along with more than 15 subcontractors and vendors under contract with Crowley.
Under the Navy contract, Crowley's logistics support vessel CMC 450-10, tug Sea Valor, Barge 250-6 and tug Sea Cloud have served as support vessels and to transport crucial equipment for the project from the mainland to Hawaii. The Sea Cloud is currently transporting gear used during phase I, that is no longer in use, back from Hawaii to the mainland.
During Phase II, which began October 15, Navy divers began using Crowley's logistics support barge CMC 450-10 as a dive platform. The first of two Navy scuba teams from the MDSU entered the shallow-water recovery site in mid-October to thoroughly survey the Ehime Maru's exterior. The CMC 450-10 serves the divers as a base of operations, and is being kept at a six-point moor above the sunken vessel. Because the barge is outfitted with winches and anchors, Crowley is capable of positioning it in fixed mooring of this kind at the offshore location. At this time Navy divers have installed two inclinometer devices used to assure the ship's incline, and ladders at the port side of the Ehime Maru for use by surface-supplied divers. They have also attached marker buoys to the vessel to help identify the position of the ship's bow and stern on the surface, and have cleared the site of hazards and obstructions on the ship's exterior and commenced surface supplied diving from Crowley's barge CMC 450-10. In addition to serving as a diving platform, the vessel is also equipped to serve as a base for environmental clean up, should the need arise. A three-month environmental study showed that no significant environmental impact would result from the planned recovery of the boat from its current location to the recovery site.
Thursday, March 01, 2007
Aircraft Rescue & Fire Fighting Vehicle Rollover Study
On-Line Reporting System
The vehicles involved in these incidents are primarily manufactured here in the US, and designed to meet current FAA specifications. There is an unanswered question as to why they are involved in these types of situations. The vehicles are designed to be capable of meeting the specific ARFF requirements, including, but not limited to, their ability to maneuver at rapid speeds both on and off road.
Our initial attack is aimed at identifying any factors that may have contributed to these incidents by collecting specific data on those events that have happened to date, and to also collect data on any future incidents that may happen. To do this efficiently, the Technical Center has developed this ARFF vehicle rollover/turnover voluntary reporting system. This new system provides a choice of an online questionnaire or off-line questionnaire (the latter suitable for faxing or mailing) in which fire departments, airport management, ARFF vehicle manufacturers, and industry personnel can report both past and present incidents. In addition, it provides a way to add supplemental information to an event that may have already been reported on this system.
The data collected from this voluntary reporting system will then be used to direct our research efforts towards the most prominent causal factors. At no time will the information be used to find fault, or place blame on individuals, fire departments, etc. This information is solely for research use. It is anticipated that duplicate reports may be submitted for the same incident. Duplicate reports will be used to fill in any voids in the data submitted by a previous responder.
The questionnaire also provides the responder the ability to select whether or not a representative from the research program can contact them at a later date to discuss the incident or clarify data input.
We thank you for your assistance, and look forward to any input you might have.