joe greiner
9th Apr 2010, 11:35 PM
Our WT club meets at a building adjacent to a railroad siding. The railhead is currently being used to off-load 100-foot-long sections of steel pipe for construction of a trans-continental gas pipeline. The pipe is approximately 3-4 feet in diameter. Three pipes are loaded onto each trailer, for subsequent transfer to a holding area about 20 miles East of Tallahassee. Past and future holding areas are located at 100-mile intervals, each to hold 100 miles of pipe, reminiscent of Amundsen's and Scott's expeditions to the South Pole. Other railroad depots are used for other holding areas.
Using 100-mile intervals, and 100-foot-long pipes, simplifies the arithmetic, i.e. 5280 pieces of pipe. At three pipes per trailer, 1760 round trips are needed. I think there are about 6 truck/trailer combinations employed. Maneuvering such combinations through city streets, and in the holding area, is a formidable challenge, even with police escorts. The trailers, however, have elegantly simple articulated mechanisms, whereby the rotation of the trailer at the fifth wheel urges a similar rotation of the rear wheel set with respect to the trailer. Thus, the turning radius is significantly reduced. The simplicity of the apparatus is remarkable: Drawbars connecting opposing sides of the fifth wheel and the rear wheel dolly cross at mid-length, through a supporting frame. The drawbars are tightened with turnbuckles.
I spoke with one of the drivers. He informed me that using these trailers is quite easy; the trailer simply does double what would otherwise be expected, in forward or reverse.
I found no patent number on one of these trailers, probably because it's so simple. US patent class/subclass of 280/426 is concerned with Land Vehicles (280) and Steering by Articulative Movement (426). I found 161 patents conforming to this; the oldest was issued in 1917; the newest was issued last month. There's an amazing variety, including hydraulic devices, microcomputers, and who knows what else, to accomplish more movements than needed here.
Moving big stuff has many applications. I thought this one was pretty cool.
About 12 years ago, I witnessed a driver of a tractor and flatbed trailer execute a reverse T-turn into a driveway off a narrow road in the Netherlands. It was executed too rapidly for me to note how he did it, but the trailer must have been remotely steered to some extent. And about 25 years ago in Washington State, long prestressed-concrete girders were transported with manually steerable rear bogies, similar to large fire trucks. On at least two occasions, gravity and/or centrifugal forces became mis-aligned with the upward (more or less) direction of the prestressing, subjecting the girder to lateral-torsional buckling, and the girder exploded.
Cheers,
Joe
Using 100-mile intervals, and 100-foot-long pipes, simplifies the arithmetic, i.e. 5280 pieces of pipe. At three pipes per trailer, 1760 round trips are needed. I think there are about 6 truck/trailer combinations employed. Maneuvering such combinations through city streets, and in the holding area, is a formidable challenge, even with police escorts. The trailers, however, have elegantly simple articulated mechanisms, whereby the rotation of the trailer at the fifth wheel urges a similar rotation of the rear wheel set with respect to the trailer. Thus, the turning radius is significantly reduced. The simplicity of the apparatus is remarkable: Drawbars connecting opposing sides of the fifth wheel and the rear wheel dolly cross at mid-length, through a supporting frame. The drawbars are tightened with turnbuckles.
I spoke with one of the drivers. He informed me that using these trailers is quite easy; the trailer simply does double what would otherwise be expected, in forward or reverse.
I found no patent number on one of these trailers, probably because it's so simple. US patent class/subclass of 280/426 is concerned with Land Vehicles (280) and Steering by Articulative Movement (426). I found 161 patents conforming to this; the oldest was issued in 1917; the newest was issued last month. There's an amazing variety, including hydraulic devices, microcomputers, and who knows what else, to accomplish more movements than needed here.
Moving big stuff has many applications. I thought this one was pretty cool.
About 12 years ago, I witnessed a driver of a tractor and flatbed trailer execute a reverse T-turn into a driveway off a narrow road in the Netherlands. It was executed too rapidly for me to note how he did it, but the trailer must have been remotely steered to some extent. And about 25 years ago in Washington State, long prestressed-concrete girders were transported with manually steerable rear bogies, similar to large fire trucks. On at least two occasions, gravity and/or centrifugal forces became mis-aligned with the upward (more or less) direction of the prestressing, subjecting the girder to lateral-torsional buckling, and the girder exploded.
Cheers,
Joe