1. Field of the Invention
The invention is related to shock absorbers and in particular to a compact shock absorber having a continuous loop woven web for use in combination with tie-down devices.
2. Prior Art
The transportation of automotive vehicles by rail requires that the vehicle be securely tied down to prevent any displacement which could possibly result in physical damage during transit. Currently the frames of the automotive vehicles are chained down to the railroad car as disclosed by Kilgus in U.S. Pat. No. 4,147,113. This type of tie-down is relatively rigid requiring the vehicle's shock absorbers to take up all of the pounding during transport. As a result, it is estimated that half of the service life of the shock absorbers is consumed during an average 1000 mile journey after leaving the assembly plant. Further the undersides of the vehicle where the tie-down chains are connected have to be strengthened significantly to be able to withstand the high forces generated during railway transportation. This increases the cost of the vehicle and decreases fuel efficiency due to the added weight. Finally the rigid chain tie-down devices currently used experience a great deal of wear requiring periodic replacement to assure their reliability.
Woven webbing similar to that used in automotive safety seat belts has been used as a tie-down for a number of various applications. For example, Van Slambrook in U.S. Pat. No. 3,885,690 discloses the use of such a webbing to support the rear end of a snowmobile on a trailer. In a similar manner Hall in U.S. Pat. No. 4,072,257 discloses the use of a woven strap to secure the load on a platform attached to the rear of a van, and Brammer in U.S. Pat. No. 3,884,450 also discloses the use of such woven straps for tying down mobile homes, trailers and other such vehicles to prevent them from being blown over or capsized by strong winds.
The invention is a shock absorber for the chain type vehicle tie-downs having a continuous loop of woven webbing, encased in rubber. This shock absorber greatly reduces the wear on the vehicle's shock absorbers and the wear on the components of the chain type tie-downs.