Thursday, May 28, 2009

The author starts this discussion looking briefly at safety issues and then moving into issues that retard the advancement to a safer world.

As will be shown, Daubert v. Merrell Dow Pharmaceuticals was a Supreme Court of the United States ruling that has been wrongly applied to engineering in many cases. This ruling allows manufacturers to continue selling dangerous products because judges do not allow plaintiff experts to testify based on Daubert. The trial judge tosses out the expert’s testimony when he or she thinks the expert did not use testing, peer review, error rate, standard procedures, and acceptance by the scientific community. It all sounds good, but some of it is pure unadulterated B.S.

If there were a question in a survey that asked, “Are you for a safer world?” The answers would be 90% in favor and 10% against safety. The 10% represents the terrible ten that causes so much trouble in our world. If the question were asked, “Who is at fault in the ATV accident with Mr. Egg in Figure 1?” The response might be 75% blaming Mr. Egg, 15% blaming the ATV manufacture, and the terrible ten blaming God who obviously punished Mr. Egg for hidden sins.
The problem is cultural as far as our attitude about safety. We all know and believe that stupid people do stupid things. This includes trial judges, lawyers, and experts. Blaming the injured and the dead in accidents is easy. Stupid people do stupid things. Therefore, there is a strong suspicion that the person involved in the accident did something dumb. The problem is we need to accept the fact that we all do stupid things on occasion. Some of the things we do are foreseeable. This human trait will never change. Let us accept that fact and hire engineers manufacturing machines and products that follow the engineering code of ethics that states, “Protect the health, welfare, and safety of the public.”

If safety works there should be evidence proving this point. The National Safety Council Injury Facts proves the point that we can live in a safer world. The death rate per 10,000 motor vehicles ranges from 33.38 in 1913 to 1.92 in 2004 .

Safety works. Some people believe there is someone keeping track of our number and when our number is up it is up. Either the person keeping track of our number changes his or her mind with vehicle accidents, or safety works and we can keep people alive and well with good solid engineering.

The Courts are the last bastion to protect consumers from unreasonably dangerous and defectively design products, machines, and structures. Daubert is not helping the author as an engineer to "Protect the health, welfare, and safety of the public."
(See the National Safety Council Injury Facts, 2005-2006 Edition Pages 110-111)

Saw guards have been problematic for decades, and saw manufacturers continue to use the very old hood guard that is attached to the splitter. The splitter lifts for wood pushed into it, and it lifts for hands. In other words, the hood guard doesn't work very well. Since the guard must be removed for non-through cuts, this guarantees the guard will be removed and left off. In addition, the guard flops all over the place, and it can hit the blade and shatter. It is almost a relief to remove the guard.

Safety Engineering Resources has been working on a new saw guard design. One of the early prototypes is shown in the photograph on the right above. A second generation saw guard is presently under construction and shows promise.

The Brett guard is an improvement over the hood guard. Basically, the flat guard hangs over the saw blade. The guard must be adjusted up and down for each thickness of wood. A picture of the Brett guard is shown above on the left.

There also is the new SawStop guard that stops when a finger or hotdog touches the blade. The invention is truly amazing, but it will take time to lower the cost where it can be universally used. The technology works but the guard is not economical for the average user. A surgeon or a musician would invest in the guard since they depend on their fingers for their livelihood. The price is almost $3000. Go to for more information.

Wednesday, May 27, 2009

Rhino UTV Rolls at Low Speeds

The calculations have shown that the theoretical rollover for a Rhino 450 with occupants is 12.23 miles per hours.

Center of Gravity on the Rhino 450 (with occupants) = [(32.77 inches * 1049 pounds) + (43.55 inches * 180 pounds) + (43.10 inches * 130 pounds)]/(1049 + 180 + 130 pounds) = 35.185 inches

Using this new value of the height of the center of gravity for the UTV and occupants:

Velocity for overturn = [((153.5/12)*32.2*(27.5/12))/(35.185/12)] .5

= 17.94 ft./second = 12.23 miles/hour *

Yamaha Rhino Recall

The CPSC announced on March 31, 2009, that users of Yamaha Rhinos should stop using the vehicles immediately until repairs are made by a local dealer. The CPSC investigation of the Rhino found that many of the rollover related deaths and injuries involve low speed turns on level terrain. Yamaha has volunteered to suspend sales of Rhinos until repairs can be made. The CPSC notice is shown below: