| 摘要 |
Truck tractors are connected to their trailers by fifth wheels and several companies manufacture fifth wheel assemblies. The tractors consist of a pair of longitudinally extending beams or rails to which the fifth wheel assemblies mount. Each fifth wheel manufacturer provides several types of fifth wheels, depending upon the type of trucking service being provided. Complicating the situation is the fact that the lateral spacing between the beams will differ. As a result of these variations, different types of mounting brackets have been developed to secure the fifth wheels to the trailer frames. The drop-over bracket fifth wheel mounting assembly consists of an L-shaped angle brace which complements and is slipped over the beam of the tractor; a bracket on its top connects to the fifth wheel. The flat plate method utilizes a thick, flat plate to span across and rest upon each of the beams; it also has a top side bracket. The drop-over method resists longitudinal loads very well but has been found to develop fatigue cracks as a result of lateral and lateral overturn loads. The flat plate method has proved to be a more costly, yet more effective method of preventing fatigue cracking. The present invention combines the positive features of each individual system into a single, and unitary lightweight cast mounting assembly, thereby providing structural homogeneousity which is resistant to fatigue cracking. Since the combined bracket mounts directly to the tractor beams, it can be used from tractor to tractor if necessary, with no concern for the lateral spacing between the beams of a particular tractor. |
