Many kinds of goods and the like are transported in open vehicles, e.g. in rail wagons or lorries. Goods that tend to raise dust or pollute, such as waste material, ashes and the like, should, however, be covered when tranported through built-up areas. For security reasons, e.g. organic waste should always be carried in covered transportation vehicles. Other products such as hot asphalt and the like, should be covered for several reasons, i.e. both to avoid polluting the surrounding but also to avoid a too high cooling during transportataion. Moreover, live-stock, such as pigs and cattle, transported to the slaughterhouse are normally transported in covered load-carrying spaces.
Thus, to a very large extent vehicles with an upwardly open load-carrying space are used, which at their top are covered by means of a tarpaulin or a similar detachable cover material, as this gives a high degree of flexibility in use. The tarpaulin is removed when the load-carrying space is loaded in order that loading may take place from above by means of a loading device or crane or the like. The tarpaulin is then placed or secured on the top. This is, however, a slow process and, consequently, various means for the mechanical placing and removing of tight fitting tarpaulins have been developed, preferably for lorries or rail goods wagons.
A cover system for lorries is known, wherein a tarpaulin is wound onto a spool-like means in essentially the same manner as a blind. The winding may be manual and operated by means of a handle as it is known from U.S. Pat. No. 2,976,082, or it may be mechanical, e.g. with a spring-motor, as it is known from U.S. Pat. No. 4,380,350. Such a winding system has the great advantage that the tarpaulin takes up only very little spaces when it is draw aside, i.e. when it is rolled up. On the other hand, this construction has the very big disadvantage of being highly sensitive to dust and impurities that easily stick to the bottom side of the tarpaulin. Where moist grain or sand is carried, or what is even worse, asphalt or tar products, the goods will stick to the bottom side of the tarpaulin and may prevent the winding up simply because the tarpaulin becomes too thick. If the rolling up of a tar stained tarpaulin of this sort is successful, it may often be impossible to unwind it again because it sticks together.
From U.S. Pat. No. 4,215,897, a cover system of the above type is known, in which the tarpaulin is moved along the load-supporting deck and joined in an extension over the driver's cab. This is not expedient as much as such a system cannot be fitted on a lorry, which side walls are lower than the height of the driver's cab just as it may cause problems to make room for the tarpaulin on top of the cab so that it does not become dirty if the lorry has a long load-supporting deck, and it gives a long and thus vulnerable travelling distance for the tarpaulin.
Object of the invention according to this application is to provide a cover for a load-carrying space for the mentioned type, comprising a very simple mechanical construction which is completely insensitive to dirt of any kind, and wherein the load-carrying space is completely open at the top when the cover is drawn aside.